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(4?n RECEIVED JUN 2 8 1982
RESEARCH TECHNIQUES AND METHODS FOR THE DETECTION AND PREVENTION OF CARCINOGENESIS IN THE INDUSTRIAL WORKER
GRANT REFERENCE NO. VC 7.0
UNIVERSITY OF LOUISVILLE HEALTH SCIENCES CENTERSCHOOL OF MEDICINE GRADUATE SCHOOL CANCER CENTER
REPORT FOR THE CHEMICAL MANUFACTURERS ASSOCIATION (FORMERLY MANUFACTURING CHEMISTS ASSOCIATION)
CMA 002992
INVESTIGATORS CARLO H. TAMBURRO, M.D., PRINCIPAL INVESTIGATOR CHARLES E. KUPCHELLA, PH.D., CO-PRINCIPAL INVESTIGATOR JOHN L. WONG, PH.D., CO-PRINCIPAL INVESTIGATOR
PROGRAM INVESTIGATORS G.fC BARROWS, M.D. J. T. DU, PH.D. E. ESPINOSA, M.O.
R.C. FELDHOFF, PH.D. H.P. FORTWENGLER, M.S.
G.R. SCHRODT, M.D. G. SONNENFELD, PH.D. U.N. STREIPS, PH.D.
M.T. TSENG, PH.D. W.J. WADDELL, M.D.
ii CMA 002993
CONTRIBUTING INVESTIGATORS (Continued)
LASLO MAKK, M.O., CLINICAL INSTRUCTOR DEPARTMENTS OF PATHOLOGY AND COMMUNITY HEALTH
DIRECTOR, DEPARTMENT OF PATHOLOGY ST. ANTHONY HOSPITAL
HANS POPPER, M.O., PROFESSOR STRATTON RESEARCH LABORATORY FOR THE STUDY OF LIVER DISEASE
MOUNT SINAI SCHOOL OF MEDICINE NEW YORK, NEW YORK
JOHN P. SAN002, M.S., INSTRUCTOR DEPARTMENT OF COftIUNITY HEALTH
G.R. SCHRODT, M.D., PROFESSOR AND CHAIRMAN DEPARTMENT OF PATHOLOGY
G. SONNENFELD, PH.O., ASSISTANT PROFESSOR DEPARTMENT OF MICROBIOLOGY & IMMUNOLOGY
U.N. STREIPS, PH.D., ASSOCIATE PROFESSOR DEPARTMENT OF MICROBIOLOGY 4 IMMUNOLOGY
C. H. TAMBURRO, M.D., PROFESSOR LIVER RESEARCH CENTER
DEPARTMENTS OF MEDICINE ANO COMMUNITY HEALTH
M.T. TSENG, PH.O., ASSOCIATE PROFESSOR DEPARTMENT OF ANATOMY
W.J. WAOOELL, M.O., PROFESSOR AND CHAIRMAN DEPARTMENT OF PHARMACOLOGY ANO TOXICOLOGY
RAYA WARICK, PH.D., RESEARCH ASSOCIATE CANCER CENTER
JOHN L. WONG, PH.D., PROFESSOR, DEPARTMENT OF CHEMISTRY
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CONTRIBUTING INVESTIGATORS
G.H. BARROWS, M.O., ASSISTANT PROFESSOR DEPARTMENT OF PATHOLOGY
JOHN L. CREECH, JR., M.D., CLINICAL ASSISTANT PROFESSOR DEPARTMENTS OF SURGERY ANO COMMUNITY HEALTH MEDICAL DEPARTMENT, B.F. GOOORICH COMPANY
J. T. DU, PH.O., RESEARCH ASSOCIATE LIVER RESEARCH CENTER DEPARTMENT OF MEDICINE
E. ESPINOSA, M.D., PROFESSOR DEPARTMENT OF PATHOLOGY
R.C. FELDHOFF, PH.D., ASSISTANT PROFESSOR DEPARTMENT OF BIOCHEMISTRY
H.P. FORTWENGLER, JR., M.S., RESEARCH ASSOCIATE LIVER RESEARCH CENTER DEPARTMENT OF MEDICINE
RICHARD A. GREENBERG, PH.O., PROFESSOR AND ACTING CHAIRMAN DEPARTMENT OF COMMUNITY HEALTH
CHARLES E. KUPCHELLA, PH.O., ASSOCIATE PROFESSOR ASSOCIATE;.DIRECTOR of CANCER CENTER; PROFESSOR AND CHAIRMAN DEPARTMENT OF BIOLOGICAL SCIENCES MURRAY STATE UNIVERSITY
GARY LISS, M.D., M.P.H., CLINICAL INSTRUCTOR DEPARTMENT OF COMMUNITY HEALTH
NIOSH/ROBERT A. TAFT LABORATORY; CINCINNATI, OHIO
CAROLYN MARLOWE, B.A., RESEARCH ASSOCIATE DEPARTMENT OF PHARMACOLOGY & TOXICOLOGY
presently
iii CMA 002994
ANIMAL STUDIES:
81. Characterization of Hepatic Enzyme Changes in Rats with Prolonged Vinyl ChioriGe Exposure: Decreased Glucose-6-Phosphata$e Activity ...........................................................
34
32. Morphological Alterations in Livers of Rats Exposed to Vinyl Chloride............................................................................................................... 34
83. Alterations in the Oxidizing and Detoxifying Systems of Rat Liver After Prolonged Exposure to Vinyl Chloride ..................... 33
84. Oxidative and Detoxifying Ability of Liver Mesenchymal versus Parenchymal Cells in the Metabolism of Xenobiotics ................. 41
HUMAN STUDIES:
85. The Effectiveness of Indocyanine Green (ICG) Clearances in the Detection of Liver Injury............................................................ 43
86. The Assessment of Bile Acids versus Indocyanine Green (ICG) Clearances in the Detection of Chemical Liver Injury Chemical in Exposed Humans..........................................................................................46
C. Study of Glycosaminoglycan Changes in the Detection of Hepatic Fibrotlc Injury in Chemical Exposure and Hepatic Cancer Development; Investigator - C. E. Kupchella and R. WarIclc ... 51
ANIMAL STUDIES:
Cl. The Study of Glycosaminoglycan Changes in Livers of Animals Bearing Metastasizing Hepatomas ....................................................... 51
C2. Significance of Tissue Glycosaminoglycan Elevations in Hepatic Necrosis and Regeneration ................................................... 51
HUMAN STUDIES:
C3. Characterization of Glycosaminoglycan Patterns in Humans with Angiosarcoma ..................................................................................... 51
C4. Evaluation of Glycosaminoglycan Analysis of Urines of Chemically-Exposed WorXers .................................................................... 51
C5. Characterization of Glycosaminoglycan Patterns in the Identification of Chemical and Nonchemical Injury of the Liver................................................................................................................... 51
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rjyiA 002997
RESEARCH TECHNIQUES AND METHODS
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FOR THE DETECTION AND PREVENTION OF CARCINOGENESIS IN THE INDUSTRIAL WORKER
Program Final Report
Table of Contents
Investigators......................................................
ii
Contributors....................................................... *.........................................
iii
I. Introduction ................................................................................................................... 1
II. Sunraarles of Research Programs ............................................................................ 3
III. Research Programs and Results ............................................................................ 16
A. Studies of Human Imnunological Systems In the Detection of Vinyl Chloride and Other Chemical Injury; Investigators - H.P. Fortwengler, Jr., and C.H. Tamburro.................................................................... 17
A1. Evaluation of Immunocompetence of Workers Chronically Exposed to Vinyl Chloride....................
17
A2. Assessment of the Leukocyte Adherence Inhibition Test for the Detection of Angiosarcoma of.the Liver .................................. 21
A3. Assessment of Vinyl Chloride-Induced Angiosarcoma Antigen for the Detection of Latent Angiosarcoma in Exposed Workers.....................................
x
A4. Study of Human Leukocyte Antigen (HLA) Frequencies in Chemically-Exposed Workers ...................................................................
22 25
AS. Identification of the Endothelial Cell as the Cell of
Origin for Vinyl Chloride-Induced Angiosarcoma of the Liver . ................................................................................................................ 30
B. Study of Hepatic Biochemical and Enzymatic Systems for the
/
Identification of Vinyl Chloride Chemical Injury and Cancer
Development: Animal and Human Studies; Investigators - J.T. Du,
M.T. Tseng, and C.H. Tamburro................................................................... 34
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G2. Circulating Antigens and Autoantibodies in Vinyl ChlorideAssociated Liver Oisease........................................................................
H. Use of Isolated Mammalian Liver Calls for the Study of Chemical - Monomer Metabolism; Investigator - R.c. Feldhoff .............................. 87
HI. Isolation of Mammalian Liver Cells for the Study of the Metabolism of Chemical Monomers .................................. ..... 87
H2. The In Vitro Study of Albumin Synthesis by Liver from Human Biopsies.................................................................................................. 87
I. The Study of Tissue Disposition of Industrial Chemicals: The Vinyl Chloride Example; Investigator - W.J. Waddell ana C. Marlowe...........................................................................................................92
II. The Use of Whole Body Autoradiography in the Specific Tissues. Localization of Accumulated and Retained Industrial Chemicalsand their Metabolites ....
92
IV. Lists of Publications, Abstracts, Preprints, and Publications
in Preparation .............................................................................................................. 99
A. Publications................................................... ..........................................,. . . 100
B. Abstracts................................................................................................................. 102
C. Preprints.................................................................-..........................................
D. Publications in Preparation Titles ........................................................... 105
V. Appendix (copies of IV., A, B, C)....................................................................106
CMA 002999
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0. Histologic and Morphometric Analysis: A'MeaFTS"or-sie___ -Hepatic Injury in Chemical'Workers; Investigators 6.H. Barrows, G.R. Schrodt, and C.H. Tamburro .................................. 56
Dl. Morphometric Assessment of Histological Lesions Character istic of Vinyl Chloride Injury ......................................................... 56
02. Computer-Assisted Morphometric Analysis as a Rapid Means of Determining Collagen Content ............................................................... 56
03. Development and Assessment of the Morphometric Method of Analysis of Collagen Content from Human Liver Biopsies Relationship to Age..................................................................................... 56
04. Light Microscopic Assessment of Various Histological Lesions Found in Liver 8iopsy Tissue Obtained from Vinyl Chloride Workers ......................................................................................... 56
E. Studies of Vinyl Monomer Chemicals and Their Metabolites Using Chemical Structure and Synthesis in the Determination of Toxicity of These Agents;Investigator - J.L. Wong ............................
67
El. Synthesis, Purification, and Utilization of Vinyl Chloride Metabolites in Mutagenicity and Carcinogenicity Studies . . 68
E2. Detoxification Studies of Vinyl Chloride and Its Metabolites...................................................................................................... 70
E3. Vinyl Chloride Metabolite Detection--ChToroacetic Acid ... 72
F. Assessment of Assays for the Carcinogenic Potential of
Industrial Chemicals Using Prokaryotic and Eukaryotic Systems; Investigators - U.N.Streips and G. Sonnenfeld.......................................... 74
FI. Further Development of Bacterial Systems for Testing,
Carcinogenicity and'Mutagenicity of Chemical Agents Used in the Manufacturing of Vinyl Chloride and Synthetic Rubber............................................................... .... , . . ..........................74
F2. Preliminary Studies on the Use of Interferon Induction as an Indicator of Mutagenicity and Carcinogenicity of Chemicals.......................................................................................................... 76
G. The Study of Liver Tissue Antigens and Antibodies in the Detection of Vinyl Chloride Injury; Investigator E. Espinosa.............................................................................................................. 80
Gl. The Study of Tissue Antigens From Liver Tumors, Angiosar coma, and Hepatomas.....................................................
80
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program ana the human xeaicai surveillance program which were onpmg
concomitantly curing the research periods of this study. This has led to a large body of literature which has changed the medical approach to the screening, identification and verification of occupationally-related chemical injury.
Although the contractual funding of this grant was only three years, each year was funded separately with varying time intervals between the funding from year to year so that almost six years have evolved between the initiation of these studies and this final report. This report, therefore, summarizes the work accomplished during this six-year interval and the related work which is still ongoing.
The investigators' reports vary in the degree of detail depending upon whether their work is in the process of being published or has already been published. Work not yet published is described in greater detail; published
work is accompanied by a copy of the actual article(s) attached in the Appendix.
The investigators wish to express their appreciation to the B.F. Goodrich
Company and especially to the entire management of its Bells Lane, Louisville plant. The continued cooperation and help of the plant managers, Philip Lawrence, Gabriel Le Febvre, Edward L. Beeler and especially Raymond Pruitt, Personnel Manager, along with Dr. John Creech, Jr., and the medical department staff, requires special acknowledgement.
The investigators also wish to thank their laboratory and research for their devoted work, and to thank Or. Harold Boyer, Vice President Health Affairs, and Dr. Joseph X. Musacchia, Dean of the Graduate School, their administrative efforts, and especially, Mrs. Vicky Strong for
patient secretarial support.
for for her
A special thanks is given to Dr. Kathleen O'Connell without whose help and support completion of the periodic and final reports would have been much more difficult.
Finally, and very Importantly, the participation and cooperation of the entire work force of the B.F. Goodrich Bells Lane Plant, and their representative unions--the Distillery Workers Union, the International Brotherhood of Electrical Workers #369, the International Association of Machinist Workers #681, and Pipefitters Union Local #522--is acknowledged with appreciation. This work would have been impossible without the active Involvement and help of the workers. The objectives of this task-' were all directed toward Improving and maintaining the best possible work environment.
Again, a thank you to all who have contributed to this effort.
CMA 003001
INTRODUCTION
In 1974 Or. John L. Creech, Jr., a surgeon and the plant physician for B.F. Goodrich's Chemical Plant on Bells Lane In Louisville, Kentucky, identi fied the Increased occurrence of hepatic angiosarcoma In workers Involved in polyvinyl chloride manufacturing. This discovery led to the implementation of an industrial cancer control, detection and prevention program at the Louis ville B.F. Goodrich Plant involving approximately 1,800 workers: 1,200 were active employees and 600 were previously employed Individuals. The University of Louisville, In cooperation with the B.F. Goodrich Company, developed and implemented the program and has continued to follow this cohort of workers clinically and epidemiologically.
A proposal submitted to the Chemical Manufacturers Association, formerly the Manufacturing Chemists Association, to foster scientific research in better technical methods for the detection and prevention of chemical injury and carcinogenesis in industrial workers was awarded in 1976. These investi gations covered nine general areas of interest and involved both animal and human studies. The studies included: (A) the use of the human immunological system for the detection of injury from vinyl chloride and other chemicals, (B) the assessment of hepatic biochemical enzymatic systems to detect and characterize vinyl chloride and other chemical injury, (C) the use of tissue and urinary glycosaminoglycan changes for early detection and diagnosis of chemical injury including cancer development, (0) the histological evaluation of liver tissue from chemical workers, and the assessment, of its collagen content as an indicator of chronic latent injury, (E) synthesis and analysis of vinyl chloride intermediate and end products to further understand its biological metabolism and removal, (F) the identification and assessment of cell assays to determine the carcinogenic potential of industrial chemicals, (G) the evaluation of tissue antigenic systems for detecting chemicallyinduced carcinogenesis, (H) exploratory studies for the use of isolated human liver cells to determine individual ability to detoxify chemicals, and (I) the further assessment of vinyl chloride metabolism by the use of whole body autoradiographic technique.
Each of these areas of study were directed toward four major objectives: (1) to better characterize and understand the pathogenesis of chemicallyinduced injury, especially vinyl chloride injury, (2) to characterize the mechanisms of chemical injury and the body's biological defense to this injury using animal studies, (3) to evaluate and assess old and new biochemical parameters for the detection and verification of chemical injury in humans, and (4) to develop new techniques that could be applied to the problem of identifying occupationally-related chemical injury for purposes of preven tion.
Many of the original objectives of the individual studies have been changed or modified because of developments and discoveries in both the animal
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CMA 003000
SUMMARIES OF RESEARCH PROGRAMS
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evidencesuggested that the tumor antigens found were distinctive for each histological type of tumor. Studies were undertaken to determine whether angiosarcoma tumor antigens would provide specific immune reactions that could be utilized as a specific test for vinyl chloride-induced tumor development. Lymphocytes from normal and liver diseased individuals were isolated and then grown in the presence of a liver reagent prepared from either normal indi viduals or individuals who had angiosarcoma. Reactivity of lymphocytes was assessed by determining the incorporation of 3H-thymidine into stimulated cultures as compared to unstimulated cultures. A comparison study was per formed between vinyl chloride plant workers and nonchemical plant workers utilizing reactions of lymphocytes to normal and angiosarcoma liver reagents. The lymphocytic response was also studied in vinyl chloride-exposed and non vinyl chloride-exposed workers with and without evidence of liver disease. Initially, specific reactivity was seen only among vinyl chloride workers. Although these inital results were provocative, subsequent studies with large control populations demonstrated similar reactivities. The lack of further occurrences of angiosarcoma in the cohort worker population prevented further characterization of the tumor antigen and restudy of the earlier findings.
A4. Study of Histocompatibility Leukocyte Antigen (HLA) Frequencies in Chemically-Exposed Workers
This study involved the search for HLA tissue types which may identify individuals susceptible to chemically-induced injury. In 1976 MulvIbgU suggested genotyping as a means of screening potential employees for ant^p> subtypes which may predispose them to neoplastic development after occupa tional exposure. It was prompted by the suggested increased occurrence of HLA-B27 antigen in workers with occupational asbestosis. The HLA frequencies in polyvinyl chloride manufacturing workers were compiled to determine if any increased genotype occurrences were associated with angiosarcoma or other chemically-related liver disease. Nine hundred individuals were eligible for this study: 538 individuals were HLA tissue typed and 30 different HLA-A, HLA-8, and HLA-C antigens were assessed. Preliminary comparisons were made with the HLA frequencies in vinyl chloride workers^ with and without liver disease, and later in those with liver disease of chemical vs. nonchemical origin. HLA frequencies were also analyzed in those individuals with and without biochemical evidence of liver injury. HLA-B15 was found to occur with a greater frequency among chemical workers with live* disease than in "control" and "normal" populations. The HLA-815 occurrence was greater among those with chemical liver injury, although it was not statistically significant. Two other HLA markers occurred with unusual lower frequency.
A5. Identification of the Endothelial Cell as the Cell of Origin For Vinyl Chloride Angiosarcoma of the Liver
There has been considerable disagreement as to the cell of origin for liver angiosarcoma, a nonparenchyma1 cell malignancy of the liver. This is of
CMA 003004
PROGRAM A
STUDIES OF HUMAN IMMUNOLOGICAL SYSTEMS IN THE OETECTION OF VINYL CHLORIDE AND OTHERS CHEMICAL INJURY; Investigators - H. P. Fortwengler, Jr., and C. H. Tamburro
Al. Evaluation of Immunocompetence of Humans Chronically Exposed to Vinyl Chloride
The scientific literature is replete with the demonstrations of immunodepression as a manifestation of medical disease, especially cancer. Lymphocytes (T cells) can be cytotoxic to human tumor cells and are often found decreased or poorly functioning in cancer patients resulting in various degrees of immunodepression. The immunocompetence of a cohort of chemical worxers was studied to determine if there was any evidence that (a) varying degrees of prolonged exposure to vinyl monomers was associated with immu nological suppression, (b) the immune response was impaired in workers with exposure-related liver injury including angiosarcoma, and (c) exposure caused changes in immunological function which were Identifiable in the pre-cancerous stages. The imnunocompetence of 75 employees with demonstrated liver disease and 225 individuals without clinical or laboratory evidence of disease was studied. No significant clinical or laboratory evidence of impaired inmunocompetence was found in the immunological parameters studied, nor were differences seen among the various subpopulations of workers.
A2. Assessment of the Leukocyte Adherence Inhibition Test for the Detection of Angiosarcoma of the Liver
Halliday et al. (1974) and Thompson (1976) had reported the development of a leukocyte adherence inhibition test which had Identified the clinical stages in colon cancer. Similar findings were reported In Individuals with hepatic cancer. This study was undertaken to determine the feasibility of applying this newly developed technique to*.* screen, vinyl chloride-exposed workers for angiosarcoma of the liver. It was assessed in a number of chemical and nonchemical workers who had cancer. This test system lacked sufficient reproducibility to be considered for clinical use.
A3. Assessment of Vinyl Chloride-Induced Angiosarcoma Antigen for the Detection of Latent Angiosarcoma in Exposed Workers
New antigens arise from tumors formed as a response to carcinogens. Their presence in methylcholanthrene-induced sarcomas was discovered by Foley in 1953. This discovery in mice was verified and extended by Prehn and Main (1957) to conclude that there were antigens particular to and specific for tumor tissue. Subsequent evidence of tumor antigen was found.in humans by the He!1stroms, Vankey, Halliday, Maluish, Thompson, and others. The majority of
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CMA 003003
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studies were conducted in saauential expertise
exposing Soraaue-Dawle'' "its
to 10,000 ppm vinyl chloride for a period of up to 300 exposure hours. These
studies demonstrate various adaptive changes in liver parenchymal calls that
were not identifiable by conventional clinical laboratory test (COLT). These
data illustrate the limited usefulness of COLT in identifying early liver cell
changes even during high levels of exposure.
82. Morphological Alterations in Livers of Rats Exposed to Vinyl Chloride
Sequential morphological assessments were performed in the rats from both chronic exposure experiments utilizing light and electron microscopy. Light microscopic findings included an increase in liver cell polyploidy, double nucleated cells, and areas of focal hepatocellular hyperplasia without evidence of cellular injury or increased fibrosis. Electron microscopic changes included proliferation of smooth endoplasmic reticulum without evidence of other subcellular organelles, or Increased collagen deposit in the Space of Oisse.
33. Alterations of Oxidizing and Detoxifying Systems of Rat Liver After Prolonged Exposure to Vinyl Chloride
A second long-term study, based partly on the results from the B1 study, was conducted to determine the adaptive capability of the detoxifying sys^w of liver cells. Glutathione reductase activity, glutathione content, gl^p> thione epoxide-S-transferase (GEST; Glutathione transferase E), and glutathione aralkyl-S-transferase (GAST; glutathione transferases A&B) were measured in rats exposed to vinyl chloride and to chloroethanol, a vinyl chloride metabolite. A third set of studies was conducted to compare these detoxifying enzymes In rats exposed to vinyl chloride and excessive alcohol consumption. These studies illustrated the adaptability of liver cells to prolonged exposure to xenobiotlcs. Liver cells showed increases in reduced glutathione and glutathione reductase activity and subsequent Increases in GEST and GAST, reflecting a progressive increase in the liver cells' capacity for detoxification of vinyl chloride's toxic intermediates. Concomitant alcohol consumption appears to Interfere with this detoxifying capability and appears to place the hepatocyte at greater risk of malignant transformation.
84. Oxidative and Detoxifying Ability of the Liver Mesenchymal vs. Parenchymal Cells in the Metabolism of Xenobiotlcs
Another aspect of the prolonged vinyl chloride exposure studies was to determine the oxidative and detoxifying capability of various liver cells. In collaboration with Dr. Feldhoff, the oxidative and detoxifying ability of the liver mesenchymal versus parenchymal cells was studied by determining 450, glutathione reductase, GEST, and GAST in liver hepatocytes and endothelial cells.
6
great importance since the identification of the type of cell responsible for malignant transformation could provide the basis for a better understanding of chemically-induced carcinogenesis. This was particularly relevant to vinyl chloride-Induced liver cancer since vinyl chloride is predominantly metabo lized and detoxified by hepatocytes and produces a malignancy of the liver that is nonparenchymal in origin. Considerable controversy arose as to whether the cell of origin was a macrophage (Kupffer cell), a fibroblast, or an endothelial vascular lining cell. The recent identification of Factor VIII production by endothelial lining cells led us to determine whether liver angiosarcoma tumor contained increased amounts of coagulation Factor VIII. Factor VIII Is a large protein, often called antihemophilic factor, found differentially In endothelial cells, platelets, and megakaryocytes. The studies described herein demonstrated Factor VIII presence in endothelial lining cells of arterial and venous vessels in normal liver, as well as In the cells of angiosarcoma. Histological verfication of the cell type was deter mined by light microscopy of the same tissue sections of the tumor. This verified the endothelial cell as the cell of origin In angiosarcoma.
PROGRAM B
STUDlf OF HEPATIC BIOCHEMICAL AND ENZYMATIC SYSTEMS FOR THE IDENTIFICATION OF VINYL CHLORIDE CHEMICAL INJURY AND CANCER DEVELOPMENT: ANIMAL AND HUMAN STUDIES; Investigators - J. T. Du, M. T. Tseng, and C. H. Tantourro
Bl. Characterization of Hepatic Enzyme Changes In Rats With Prolonged Vinyl Chloride Exposure: Decreased Glucose-6-Phosphatase Activity
Considerable concern was initially raised concerning the best technique for screening individuals with chemical exposure. At present, federal testing requirements recommend enzyme studies related to liver parenchymal cells. However, clinical evidence indicated that not only were the hepatocytes Injured but so were Kupffer and endothelial cells, and that the endothelial cell or Kupffer cell was the malignant cell of origin. Tn addition, studies to determine the sequential enzymatic changes which occurred with prolonged continuous vinyl chloride exposure similar to that seen with the worker population were needed. Most studies at this time had been conducted with short term exposures. The early animal studies Included assessment of the standard clinical, biochemical, and enzymatic studies and later explored the enzymatic changes occurring in various subcellular organelles. These included (a) markers for microsomal enzymes related to the metabolism of vinyl chlo ride, -450, NADPH-cytochrome reductase, and mixed function oxidase, (b) cyto solic "enzymes related to glutathione metabolism and glutathione content, (c) mitochondrial marker cytochrome-C-oxIdase, (d) cytosolic enzymes glucose-6-phosphatase, glucose-6-phosphate dehydrogenase related to pentose phosphate pathway, and (e) nucleic acid synthesis. In addition, protein synthesis was evaluated by In-vitro incorporation of ^H-leucIne. These
003005
hold promise as a potential cetect^1WiiSrTyr:5Iver""i'njury, whether chem^rel or not. 'Bile acics have the acvantage of being natural biological substances whicn may be tanen orally for screening clearance studies.
PROGRAM C
STUDY OF GLYCOSAMlNQGLYCAN CHANGES IN THE EARLY DETECTION OF HEPATIC FIBROTIC INJURY IN CHEMICAL EXPOSURE AND HEPATIC CANCER DEVELOPMENT; Investigators - C. E. Kupchella ana R. Waricx
ANIMAL STUDIES:
Cl. The Study of Glycosaminoglycan Changes in Livers of Animals Bearing Metastasizing Hepatomas
C2. Significance of Tissue Glycosaminoglycan Elevations in Hepatic Necrosis and Regeneration
Animal studies to determine the sequence of GAG changes in- experi mental ly-induced fibrotic liver injury, and the relationship between GAG patterns in tumor tissue and in urine were studied In animals with fast vs. slow growing, metastasizing vs. nonmetastasizing, chemically-induced ^d transplantable liver cells tumors.
The experimental animal studies identified heparan sulfate ( a type of GAG) elevation in hepatic tissue undergoing fibrotic changes and that the increased levels were reflected in the urine. Both heparan sulfate and hyaluronic acid levels were 3-4 times higher in experimentally- transplanted liver tumors than In normal controls. Urinary excretion reflects both tumor GAG composition and size. Livers from animals bearing metastasizing hepatomas had a 10-fold great concentration of nonsulfated neutral uronic acid positive material than animals bearing nonmetastasizing hepatomas. Finally, hepatic necrosis was shown to be accompanied by significant tissue GAG elevation; hepatic regeneration was not.
HUMAN STUOIES:
C3. Characterization of Glycosaminoglycan Patterns In Humans with Angiosarcoma
C4. Evaluation of Glycosaminoglycan Analysis of Urines of Chemically-Exposed Workers
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The mesenchymal cells were shown to be capable of oxidizing xenobiotics which require'-450 and mixed function oxidases, although this capability was less than that"of the parenchymal cells by a 70 to 1 ratio. GEST and GAST activity were also present but In the ratio of 1 to 65, and 1 to 500, respec tively. These results demonstrate that the nonhepatocytic liver cells have the capability to activate vinyl chloride and other similar xenobiotics, al though to a lesser degree than hepatocytes. However, their ability to de toxify vinyl chloride metabolites is significantly less and may contribute to the reason for nonmesenchymal cell malignant transformation.
B5. Effectiveness of Indocyanine Green (ICG) Clearances in the Detection of Liver Injury
A chemically-exposed worker cohort of almost 1,000 individuals were medically screened to determine the effectiveness of ICG clearances versus standard biochemical studies of the liver to identify latent hepatic Injury. Alanine aminotransferase (ALT/SGPT), aspartic aminotransferase (AST/SG0T), gamma glutamyl transpeptidase (GGPT), . alkalIne phosphatase (AP), and total bilirubin (TB) were assessed in contrast to 3 different dose levels of ICG. Positive predictive values as well as the specificity and sensitivity of each of the screening tests were determined in "normal" and "abnormal" worker populations as well as in those with hepatic disease and nonhepatic disease. Chemical and nonchemical liver injury were also determined in analysis of their relationship of work histories to the biochemical abnormalities. These studies demonstrated that ALT/SGPT was the screening test with the highest sensitivity and specificity among federally-required studies. ICG clearance, even at the low dose, clearly remained the best overall screening test for the detection of subclinical hepatic disease.
86. Assessment of Bile Acids vs. Indocyanine Green (ICG) Clearances in The Detection of Liver Injury Due to Chemical Exposure in The Human Population
Fasting serum bile acid levels and ICG clearances were performed for 400 employees with varying degrees of chemical exposure1 as well as biochemical injury related to vinyl chloride exposure. Bile acid levels, ICG clearances and standard enzymatic biochemical tests were assessed regarding their ability to identify normal individuals. Individuals with liver disease of nonchemlcal origin, and-individuals with liver disease with chemical origin, correctly. These more sensitive studies were to identify early chemical Injury; six other enzyme studies were also conducted regarding more specific enzymes for hepa tocellular Injury, such as sorbitol dehydrogenase. One thousand seven hundred and sixty human seras taken from 900 exposed workers were assessed and the results compared to the vinyl chloride exposure.
Fasting serum bile acids demonstrated a high sensitivity separating normal versus abnormal individuals with early or latent liver dysfunction, particularly chemically-induced types of injury. Fasting serum bile acids
CMA 003006
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periportal, and pericentral areas in' 4 different anatomical locations of human liver of 4 different age groups. These studies demonstrated that the collagen content of the liver varies with age, increasing after the fourth decade. The collagen distribution shows an increased desposition in the perisinusoidal and m1d2onal regions with age. The computerized morphometric readout demonstrated that the collagen estimates vary from 2-6* of the total liver globules. (This does not include capsular fibrosis or collagen support tissue about major vessels.)
04. Light Microscopic Assessment of Liver Tissue Obtained from Vinyl Chloride Horners Characterizing Various Histological Lesions
Light microscopic assessment of liver tissue obtained from vinyl chloride and nonvinyl chloride workers illustrated that focal hepatocellular hyper plasia and focal mixed hyperplasia, sinusoidal dilitation and focal areas of increased reticulum characterized chemical injury could be identified in a prospective blind study and that those individuals with these identified lesions had the highest correlation with their vinyl chloride accumulative exposure ranked months; this correlation was not seen with other chemicals within their exposure environment.
PROGRAM E
STUOIES OF VINYL MONOMER CHEMICALS AND THEIR METABOLITES USING CHEMICAL STRUCTURE ANO SYNTHESIS IN THE DETERMINATION OF TOXICITY OF THESE AGENTS; Investigator - J. L. Wong
El. Synthesis, Purification, and Utilization of Vinyl Chloride Metabolites In Mutagenicity and Carcinogenicity Studies
E2. Detoxification Studies of Vinyl Chloride and Its Metabolites
E3. Vinyl Chloride Metabolite Detection--Chioroacetlc Acid
In order to further elucidate the intermediate metabolism of vinyl chloride, especially with regard to the carcinogenic potential of Its inter mediate metabolites--chlorooxirane and chloroacetaldehyde--laboratory syn thesis of these two putative metabolites was performed. The materials were utilized to further study the detoxification of these agents and their effect on bacterial systems. Additional studies were conducted to determine the ability to identify chloroacetic acid by mass spectrometry and gas chromatog raphy.
These studies illustrated that although chlorooxirane and chloroacetalde hyde eventually give the same final product, the rate of reaction and the
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10
C5. Characterization of Glycosaminoglycan Patterns In the Identification of Chemical and Nonchemical Injury of the Liver
The study of glycosaminoglycans, glycoproteins involved in wound healing and scar formation, as potential indicators of chemical injury, fibrosis, and cancer development was conducted in a large cohort of exposed workers. Analy sis of GAG in tissue and urine was performed in individuals with angiosarcoma and heptocellular tumors, in individuals with chemical and nonchemical liver injury, and in individuals with chemical liver abnormalities and in normal controls. The studies indicated that human hepatic angiosarcoma and flbrotic liver disease are accompanied by elevated tissue GAGs, that the tumor tissue is different from the adjacent flbrotic areas of the liver, and that patients with angiosarcoma and primary hepatocellular carcinoma (hepatoma) have charac teristic urinary GAG patterns. These patterns are not found in "normal" indi viduals. Urinary GAG determinations give a better Indication of liver disease than ultrasound or radioisotopic scanning, and although they are not as sensi tive as transaminases or ICG clearances, fractionated GAG analysis appears to differentiate between active and inactive liver disease.
PROGRAM 0
HISTOLOGIC AND MORPHOMETRIC ANALYSIS: A MEANS OF ASSESSING HEPATIC INJURY IN CHEMICAL WORKERS; Investigators - G. H. Barrows, G. R. Schrodt, and C. H. Tamburro
Dl. Systematic Assessment of Histological Lesions Characteristic of Vinyl Chloride or Vinyl Monomer Injury
02. Computer-Assisted Morphometric Analysis as a Means of Determining Collagen Content
D3. Development and Assessment of Morphometric Method of Analysis of Collagen Content from Liver Biopsies - Normal Occurrence with Age
Vinyl monomer injury has been associated with various hepatic histo logical abnormalities. These have Included subcapsular, portal, and perisinusoidal fibrosis, as well as hyperplasia of the hepatocytes and nonparenchymal (sinusoidal) cells. The ability to assess light microscopic determina tions of fibrosis (liver tissue collagen content) using computer-assisted morphometric analysis quantitatively, was delineated. The methodologies determined the normal presence of collagen and the effect of age. Prospective analysis to determine the ability of specific histological findings to cor rectly identify vinyl monomer exposure was also done.
Both manual and computer-assisted morphometric assessment of normal collagen content identified the distribution between perlslnusoldal.
CMA 003008
PROGRAMS'
THE STUOY OF LIVER TISSUE ANTIGENS AND ANTIBODIES IN THE DETECTION OF VINYL CHLORIDE INJURY; Investigator - E. Espinosa
Gl. The Study of Tissue Antigens From Liver Tumors, Angiosarcoma, and Hepatomas
G2. Circulating Antigens and Autoantibodies in Vinyl Chloride-Associated Liver Disease
The approach to the use of tissue antigens produced by neoplasms and identified in serum, either as the antigens or autoantibodies, were studied in angiosarcoma and in chemically-induced liver cancers. Several normal tissue antigens, a tumor-associated protein antigen, and a glycoprotein liver antigen absent in individuals with angiosarcoma were identified and characterized. The finding of a missing antigen in vinyl chloride-related angiosarcoma stimulated studies of antigenic deletion in chemically-induced hepatoma and cultured human liver carcinoma cells. Two liver antigens were found to be absent. One of these antigens was shown to be normally present.in other tissues (kidney and spleen) in addition to the liver. The second antigen was detected only in the liver and was found to be unrelated to the liver-specific F antigen. Liver-specific F antigen was also studied as a possible sensitive indicator of chemically-induced liver tumor. F antigen appeared to be a^^kt in fast growing hepatoma 7777 and undetectable or very low in the slow grw^g hepatomas. The level of the F antigen did not appear to correlate with the rate of growth of these tumors; however, an Increased concentration of F antigen appears related to those tumors with the highest metastatic characteristics. Studies of cultured human cancer carcinoma cells also noted a deficiency in liver-specific F antigen similar to that of the experimental hepatoma 7777. These data support the clinical observation that tissue antigens appear to be more useful in treatment and follow-up care, while antigenic deletions may prove more important for screening and early detection.
PROGRAM H
USE OF ISOLATED MAMMALIAN LIVER CELLS FOR THE STUDY OF CHEMICAL MONOMER METABOLISM; Investigator - R. C. Feldhoff
Hi. Isolation of Mammalian Liver Cells for the Study of the Metabolism of Chemical Monomers
H2. The In Vitro Study of Albumin Synthesis by Liver from Human Biopsies
CMA 003011
12
intermediates -In the two reactions are different. Chlorooxirane conjugates instantaneously with the sulfhydral compounds, while chloroacetaldehyde takes about 2 1/2 hours for a comparative reaction. Although both routes are con verged to yield the cystelne-S-acetaldehyde conjugate, the reaction rates are vastly different, one taking minutes, the other hours to complete. Chloroacetic acid is Identifiable by mass spectrometry in liquid solutions, solu tions as small as 0.02M (2 mg/ml), while gas chromatography sensitivity was limited to concentrations of 0.2 to 2 mg/ml HjO (200 to 2,000 ppm). Use of a porous polymer solid support and formic acid is expected to Improve sensi tivity by 100-fold. Combination of GC-MS techniques appear to be the most promising approaches to the detection of end metabolic products and biological tissue.
PROGRAM F
ASSESSMENT OF ASSAYS FOR THE CARCINOGENIC POTENTIAL OF INDUSTRIAL CHEMICALS USING PROKARYOTIC AND EUKARYOTIC SYSTEMS; Investigators - U.N. Streips and G. Sonnenfeld
F1. Further Development of Bacterial Systems for Testing Carcinogenicity and Mutagenicity of Chemical Agents Used In the Manufacturing of Vinyl Chloride and Synthetic Rubber
Application of mutagenic assays for the determination of mutagenic potential of a list of environmental chemicals was conducted using improved modifications of their bacterial system. In addition, a new screening technique for carcinogenesis was developed Involving the Inhibition of interferon Induction. This was applied to several carcinogens and mutagens and compared to the effectiveness of the standard viral bacteriological assays. These studies have demonstrated improved techniques for rapid screening of large numbers of chemical formulations being utilized within an environmental region.
F2. Preliminary Studies on the Use of Interferon Induction as an Indicator of Mutagenicity and Carcinogenicity of Chemicals
The new method assessing the mutagenic/carcinogenic capabilities of chemicals using an interferon assay Is reported as well as related research regarding the controlled process of cell division In bacteria and how these findings relate to mammalian cells.
Interferon induction inhibition in contrast to the Ames bacterial assay demonstrated the ability to separate more accurately agents with more carcinogenic potential related to human occurrences.
CtAA- 00301
nonvolatile metabolites of vinyl cnloride retained in the thymus after 24 hours suggested that there was covalent binding of these metabolites to the molecules in the thymus. Possible interactions of the thymus may reflect a dual mechanism of carcinogenic action, one related to tissue damage in the liver, the other to a suppressed immune surveillance system.
CMA 003013
14
Presently, the rat has provided the most useful means of studying hepatic metabolism In mammalian cells. The intact liver, however, consists of at least four cell types which differ In their metabolic and functional characteristics. These studies were directed toward the development of clinically utillzable techniques to study human liver biopsy material In relationship to its ability to synthesize, retain, and secrete protein.
Improved techniques were also utilized for Isolation of hepatic paren
chymal and nonparenchymal cells so that nearly homogeneous populations of
cells could be studied for their oxidizing and detoxifying capabilities.
Preliminary results of this late addition to our research techniques have
proven encouraging in the adaptability of highly sophisticated laboratory
techniques to the study of human tissue in an In vitro system. It has demon
strated that animal and human tissue obtained"5y a clinical biopsy technique
are viable in an
vitro system, being able to perform normal functions
relative to albumin synthesis. The technique for the study of this tissue in
an in vitro system may be applicable to human tissue from Individuals with
varying degrees and types of cellular injury. This technique would provide
the ability to determine the oxidizing and detoxifying capability of liver
cells to various xenoblotlcs In a quantitative fashion. Although very
futuristic in its approach, it appears accomplishable since the present devel
oped methodology is clinically applicable.
PROGRAM I
THE STUDY OF TISSUE DISPOSITION OF INDUSTRIAL CHEMICALS: THE VINYL CHLORIDE EXAMPLE; Investigators - W. J. Waddell and C. Marlowe
II. The Use of Whole Body Autoradiography in Specific Tissues. Localization of Accumulated and Retained Industrial Chemicals and Their Metabolites
The need for methods which more accurately identify the sites of locali zation of chemical agents and their metabolites has obvious importance. The use of whole-body autoradiography to identify the location of radioactively tagged chemicals was studied with regard to '4C-vinyl chloride. Whole-body saggltal sections of mice exposed for three hours in '4C-vinyl chloride demonstrated that the highest levels of radioactivity in mice sacrificed at 20 minutes and one hour after removal from the vinyl chloride environment were observed in the liver, pancreas, kidney, intestinal contents, urine and bile. Concentrations of metabolites in the organs of excretion decreased continually over a 24-hour period. After nine hours removal from the vinyl chloride environment, Harder's gland, epithelium of the esophagus and intestine, and sublingual glands retained the highest levels of radioactivity, while moderate concentrations were seen in the liver, kidney, and intestinal contents. At 24 hours, the primary organs of retention were the thymus, Harder's gland, liver, and esophagus and intestinal epithelium. The high concentration of
CMA 003012
RESEARCH PROGRAMS AND RESULTS
16 CMA 003014
18
Research Results
An evaluation of immunocompetence was carried on in individuals with documented chemical hepatic injury and in those without biochemical or clinical evidence of liver injury. A second comparison was conducted between workers with high versus low exposure to vinyl chloride, utilizing our cumula tive exposure rank months (CERM) ranking. Tests for immunocompetence included enumeration of lymphocytes, determination of certain lymphocyte sufcpopulations, and response of lymphocyte to nonspecific antigens as a test of lympho cytic function.
Results of lymphocyte response to stimulation with nonspecific antigens Phytohemagglutinin (PHA), Concanavallin A (Con-A), and Pokeweed mitogen (PWM) are shown in Figure 1.
LYMPHOCYTE RESPONSE OF VINYL CHLORIDE WORKERS
(MON-SPSCIFIC AMTIGSiiS)
300 250 200 250 _ 100 -
50-
I 11 \
1 :
vim CHLCaiCE ElMS'JAE . ABOVE .*DWI (11*54)
:::::: below ,-eduji cb-w II I1
' a**
11! *j
IT a.- jli
MYTOMQWGGLUTlIltN CQNCAMVALUN A POtfWEO ,1'TOGEA
Figurc 1
Response of the other imnune parameters in high and low vinyl chloride exposure are shown in Table 1. No statistically significant difference was found between workers with high and low vinyl chloride exposure, or between unexposed invidivduals and chemical workers (Figure 2).
CMA 003016
PROGRAM A
STUDIES OF HUMAN IMMUMOLOGICAL SYSTEMS IN THE DETECTION OF VINYL CHLORIDE AND OTHER CHEMICAL INJURIES; Investigators - H.P. Fortwengler, Jr., and C. H. Tamburro.
Al. Evaluation of Inmunocompetence of Workers Chronically Exposed to Vinyl Chloride
Background
The study of the human immunological systems as a means of detecting chemical injury was initiated to determine whether or not the body's ability to recognize substances that were foreign would make specific responses that could be identified clinically. The immune response can be divided loosely into two types: antibody formation and cell-mediated responses. Our initial studies were conducted to determine whether the mediators of immunity, i.e., lynphocytes, could be identified as having any inmune defects which could be related to chemical exposure and be an early signal of an impaired immune system which might interfere with the body's normal defenses. These antibody forming cells constitute the humoral part of the human immune response. The lymphocytes are divided into at least two classes or types called B cells and T cells. The B cell lymphocytes are responsible for the synthesis and secre tion of antibody molecules, while the T cells are responsible for helping B cells. In addition, the T cells are also able to carry out a whole series of reactions in their own right. Generally these reactions involve tissue destruction, and since antibodies are usually not involved, they are called cell-mediated reactions. There has been recent thinking that the body's defense against tumors is a result of a tumor's having a unique antigen which is therefore recognized as foreign. The Immune system constantly responds against these new antigens, and in this manner, there is an ongoing Immune surveillance against tumors. Failure to react with the new antigen results in cancers, according to this theory.
Objective
1. To determine the inmune competence of chemical workers with prolonged exposure to vinyl chloride monomers
2. To compare their Immune response to those workers who had developed liver Injury, including angiosarcoma.
17
CMA 003015
20
No statistical differences were seen in these same immune parameters bet' workers with or without liver injury (Tables 2 and 3).
TABU 2
IWJNE PARAMETERS OF VC WORKS WITH AMI WITHOUT LIVER DISEASE
TEST
WVTONCMMUTiNIN STIMULATION
LIVER OISEASE 253'+3S" (n-2S)
NO LIVER disease
17*35 (n-N8)
CMOIIAVIIUM A sTimiurioM
195*36 (h-2S)
162*29 Cn-H8>
MKtvua At roots
stimulation
100*12 (n-25)
aotiJ (n-4S)
STKtFtOCOCCM. ASTI fits STIMUUTION
2081*2 (n*2<0
181^2 (n-*9>
STWmTVf* 0 STIMULATION
1*2 <x-2S)
IfeS <n-*9)
APO STIMULATION
13*6 (n-ZS)
10*9 (N*tS)
VAN1 QAM mmS-ATlON
36*9 (if2S)
31S5 (*90)
CAMION STIMULATION
1%*$ (*25)
7*1 (*09)
'tTlMLATlOi tNOtt
TABU 5
imME FARAIETERS OF VC WORKERS WITH AND WITHOUT LIVER DISEASE
TEST
WKlTt HMD CtU COUNT
LIVER DISEASE
S9001SD0* (n-25)
NO LIVER DISEASE
6650*330 (n-5D)
LTJWNOCTTt COUNT (TtKCINT)
36*2 <m25)
33*2 (n-*8)
AMOLUTf LTNAlOCTTt COIMT
. 2333*2*30 (n-2S)
2300*200 (*8)
T-CfU. MttTTtl AT 4ac (KIKWT)
57*3 <m2S)
52*2 (N-N9)
r-eot menu at *c (AIMurt)
1600tlCO (n-25)
1500*100 (n**9)
T-ctu, mrrrti at 53c (tmcint)
55*2 (<rtS>
52*2 (*7)
win muttii at JJ*e 1X0*100
(A1SOLUTI)
(n-25)
1200*100 (n*n7)
'in
Tables 4 and 5 show the results of these immunological parameters examined in old and young workers. Older individuals demonstrated significant differences in their total white count (Pc.01), percentage of lymphocytes (Pc.001), and lymphocyte reactivity to Streptolysin 0 (Pc.05) and PPO (tuberculin) (Pc.05) stimulation. We believe these findings to be age related with no relationship
to the presence of liver disease or exposure to vinyl chloride. No other statistically significant differences were found between the various groups. There Is no evidence from this data that imnunologlcal abnormalities result from chronic exposure to various levels of vinyl chloride.
CMA 003018
TABLE 1
imUNE PAAAICTERS OF VC WORKER ACCORDING TO EXPOSURE
TEST
STNfPTOCOCCAL ANTIOCN STIMULATION
ABOVE ItDIAN EXPOSURE 191**3"
(w-52)
taow ICDIAN EXPOSURE
186*38 t*-28)
STREPTOLYSIN 0 STIMULATION
8*2 (*53)
28+12 <*28)
PPO STIMULATION
29*8 <-89)
18*6 (*-23)
VAftlOASC STIMULATION
29*5 (*-58)
81*12 (if23)
CANDIDA STIMULATION
11*3 <*-53)
6*2 (*-23)
ASNLUTI LYNPHOCYTt COUNT
2355*132 (m-52)
2316*188 (if28)
T-CfU. AOACTTES AT <tC {amqlutc)
1503*101 <*-50)
1528*132 (if28)
T'CtLL ROSfmS AT J3C (AOSOLUTf)
1227*80 (*50)
1260*123 (*28)
'iTtNWJkTKM IMU
STATISTICAL SIGNIFICANCE
NONC
NQNC
NONC
NONC NONC
NONC
NONC
NONC
Mitogen induced lymphocyte transformation in VC workers and unexposed individuals
VC workers (n78)
HI Unexposed individuals (n - 21)
1 19
FIGURE 2
PHA
Corv-A
CMA 003017
Lymphocytic reaction to normal and angiosarcoma liver reagents were studied in workers with high and low exposure (above or below the median exposures for the plant) to vinyl chloride (Figure 3). No statistical dif ference was noted between the reactivities of these two groups.
LYMPHOCYTE RESPONSE OF VINYL CHLORIDE WORKERS
(TISSUE ANTIGENS)
VlftYL CHLORIDE EXPOSURE
H ABOVE ifEDIAft (N-54) :::::: BELOW noun (N-2R)
AHGIQSARCCTIA
LIVER AilTIGEH
ANTIGEN EXTRACT
EXTRACT
Figure 3
Similar studies in workers with and without liver disease also failed^* show significant differences in their lymphocytic reactivity to tid^P
reagents (Table 8A).
TABLE 8A LYMPHOCYTE REACTIVITY TO NORMAL AND ANGIOSARCOMA
TUMOR TISSUES IN VINYL CHLORIDE WORKERS WITH AND WITHOUT LIVER DISEASE
LIVER
NORMAL TISSUE
TUMOR TISSUE
LIVER DISEASE
NORMAL
2.4 0.3* 2.6 t 0.4
1.5 t 0.2
1.8 0.2
'STIMULATION INDEX SEM
003022 cvuv
TABLE A
IlfUIE PAMCTEB Of wmERS OU) VERSES YOUNG
TEST
PHYTOHCfttOCLUTINtM STIMULATION
concanavallin a
STIMULATION
P0UWEE9 M1T0GIM
stimulation
streptococcal antigen stimulation
STREPTOLYSIN 0 STIMULATION
ppo STIMULATION
VANIDASt STIMULATION
CANOIOA STIMULATION
*ST(HULATIN 1110**
"w
OLD 100**20**
(37)
1*25 (-37)
90*15 (*37)
135*35 (-33)
5*2 (-33)
36tl2 (39)
25*6 (n-38)
9l3 (37)
YOUNG 210+32 (NO)
183*25
(*09)
90*29 (-09)
135+35 (33)
21+7 P.05 (-53)
13*3 r*.os (35)
39*9 (m--39)
9+3 (39)
21
TABLE S
inilNE PAWfFTEAS OF VC NORKERS OLD VERSES TOOK
TEST
NITt tLOCO ecu.
COIDT
OLD
7150*000* (n-38)
LYNRHOCYTt COUNT
(RERCMT)
33*2 (*36)
ASSOLUTE LYNRHOCYTE 2300+200
COWT
(36)
T-CIU ROSETTES AT
9C (RERCENT)
60*2 (36)
T-CELL ROSETTES AT 1000*150
0e (aimlvti)
(30)
T-CIU. ROSETTES AT 33C (RfSCENT)
52*2 <i^36)
T-CIU ROSETTES AT 1100*100
33c (aisolute)
(n-34)
sw
YOUNG 6150*300 * *.01
(*00)
01*2 R *.001 (iHlO)
2000*100 (-00)
60+2 (--v9)
1600*100 (*00)
53*2 (OO)
1300*100 (00)
A2. Assessment of the Leukocyte Adherence Inhibition Test for the Detection of Angiosarcoma of the Liver
Background
Halliday et al. (1974) reported the development of a leukocyte adherence inhibition test which identified the preclinical stages of colon cancer. Similar findings were reported in patients with liver cancer--the primary hepatocellular type. The need for a more specific screening test, especially for those who might be developing angiosarcoma that was not clinically de tectable, led us to assess this test in our cohort population.
Objective
1. To verify the studies of Halliday and Malulsh regarding the use of the leukocyte adherence inhibition test in -the identification of carcinomas of the colon and its possible adaptation to vinyl chloride-induced angiosarcoma.
CMA 003019
target antigens, immune response, turner virus susceptibility, liver cycnc acenosine monopnosphate levels, hybrid resistance, and T-cell: 8-cell inter actions. HLA antigens are found on almost all ceils of the body except red blood cells. The major histocompatibility complexes in man are identified by
letters (A, B, C, D) and numbers (A10, 312, 02). An increased incidence of
certain HLA antigens had been shown" to 5e associated with susceptibility to certain diseases. Mulvihill (1S76) proposed that screening for these genetic markers to identify abnormal genotypes in potential employees should be done so that indiviauals who might be predisposed to neoplasia after occupational exposure would be separated from those from normal genotypes. The first occupational disease correlation reported was HLA-827 antigen which was found with increased frequency in workers suspected of having occupational asbestosis. The possibility that the histocompatible complex could be used to identify individuals at increased risk of developing chemical injury led to its study in vinyl chloride workers.
Objective
1. To determine the HLA frequency in vinyl chloride workers
2. To compare the HLA frequency in vinyl chloride workers with and without liver disease.
In order to deal with the statistical problem of multiple comparisons due to the large number of antigens to be studied, potential markMc for liver disease were identified for study: A-9, 8-15 and B-17.
Research Results
HLA determinations were done using the Terasaki microdroplet lymphocyte cytotoxicity test. HLA typing was performed on 538 of our chemical cohort population. Tissue typing included 11 HLA-A antigens, 15 HLA-B antigens and 4 HLA-C antigens. Frequency distributions were determined in our "standard" (healthy population) and compared with the "normal" groups studied by Scott et al. (1977) and the World Health Organization. The comparison of these fre quencies are found in Tables 9 and 10.
A preliminary analysis of these HLA frequencies included the comparison of a subcohort population consisting of individuals identified through the medical screening program as having liver disease. These individuals had been transferred from the main chemical plant to an ancillary plant making wooden shipping pallets, referred to subsequently as "Pallet Plant Cohort".
As seen in Table- 10 this cohort had increased frequency of HLA-815 (12 percent-normal population versus 28 percent-Pa1 let Plant Cohort).
CMA 003024
25
On the chance that non-specific reactions might be obscuring the specific reactions, workers with vinyl chloride-suspected disease (working in a non-vinyl chloride environment--Pallet Plant) were compared to workers without known liver disease (working at the Main Plant).
TABLE 8B 1H vitro LYMPHOCYTE STIMULATION BY ANGIOSARCOMATOUS liver EXTRACT
SUBJECTS
HUMBER TESTED
NUMBER OF SUBJECTS REACTIVE AGAINST:
NORMAL LIVER ONLY
NORMAL S ANGIO ANGIO ONLY
NON-PALLET
PLANT WORKERS
16
1
11
pallet
PLANT WORKERS
TOTAL
18 34
*ONE INDIVIDUAL HAD AN6I03ARC0MA
1 2
0 2* 13
At first, this appeared to be a specific reaction to the angiosarcoma tumor extract, i.e., negative reactions to normal liver with positive reactions to
tumor antigen. Initially, this type of reactivity occurred only among the vinyl chloride workers. Subsequent studies among additional nonchemical workers demonstrated similar reactivities to these liver reagents. Although these results were provocative, the lack of further occurrences of angio sarcoma in our worker population prevented us from further characterizing this (these) possible angiosarcoma antigen(s) and having the opportunity to verify these observations.
A4. Study of Human Leukocyte Antigen (HLA) Frequencies in Chemically-Exposed Workers
Background
The major histocompatibility complex of the immune system, HLA, is com posed of multiallelic genes located on one region of chromosome 6 in the human and on chromosome 17 in the mouse. The genes in this region control a wide variety of surface antigens and lymphoid functions. This major histocompati bility complex is intimately related to the understanding of transplantations, graft versus host reactions, interactions of B and T Cells, genetic control of immune responses and several other phenomena in the immunological system. Certain genetic traits appear to be controlled in animals by the genes of this complex. These include transplantation antigens, cell-mediated lympholysis,
003023
28
Table 11 illustrates the frequency of HLA-815 among the entire wor cohort at the main chemical plant. This cohort was subdivided into those with liver disease versus normal individuals based on medical screening studies and liver biopsy. HLA-815 occurred in 13 percent of the normal group versus 17 percent of the liver diseased group.
TABLE 11
DISTRIBUTION OF HLA-B15 ANTISEN AMONG CHEMICAL WORKERS WITH AND WITHOUT LIVER DISEASE
(MAIN PLANT COHORT)
Clinical Diagnosis
NORMAL
N-509 LIVER DISEASE
64 3
427 15
Total
(X)
491 (13)
18 (17)
To determine if this increased occurrence of HLA-815 was due to chemi cally-related liver injury and not due to incidental (non-occupational) liver disease, both the pallet plant and the main plant cohorts with liver disease were subclassified' into those with chemical liver injury (CLI), and non chemical liver disease (LD). The frequency of HLA-815 in these cohorts is shown In Tables 12 and 13.
Table 14- illustrates the occurrence of HLA-815 in the entire plant cohort subclassified into those without liver disease (NORMAL), those with liver disease, all types (BOTH). Those with liver disease are further subclassified into those with chemical liver injury (CLI) and those with liver disease, non-chemical in origin (LD).
MA 003026
ELA-A ANTIGENS
A1 A3 A3 A A10 All AU A29 Af30 AV31 AM33 Uni
TAJIK 9 HLA-A FREOuertClES
HEALTHY COtrttOU
34 31 33 1
7 13
7 i MD" HD MO MO
MHO 1974 OftlCSlfOP
33 49 33 17 13
11
7 3 7 MD
pAU.tr MUMT(irO)
40 37 14 11 11
7 IS
Q 4 4 7 14
HOH PALLET PUMT(SrO)
30 S3 31 33
11 U
7 19
M Totsl rwnwocp
**mt done
900 1*0%
303 ITW
3S 2091
319 300%
TAMLX 10
HU*S FREQUENCIES
HU'S ANTI COS
M 97 as 913 913 914 919 avis 917 919 9V81 *22 937 9*33 940 Unk
HEALTHY C0MT9OU
10 31 37 30
3 3 10 NO s MO 3 7 3 11 MD
M
Toctl rr***47
903 133%
190 1973 *090909
11 33 30 34
S 11
7 13
7 4 3 IT 13 HO
303
I7f%
PALLET PLA9T/9P0
11 1* 31 31
0 11 39
7 14
4 4 7 7 11 19 19
29
301%
MON PALLTT PUMT/970
9 39 30 31
3 3 19 4 *12 a 4 3 u 17 IS 13
319
301%
CMA 003025
A5. Iaentification of the Endothelial Ceil as the Cell of Origin for Vinyl Chloriae-Inauced Angiosarcoma of the Liver
Background
A search for evidence of vinyl chloride-induced tumor antigen has led to the finding that these tumors have an increased concentration of antigenic coagulation Factor VIII. Factor VIII is a known marker for the vascular lining cells of the endothelial type. Further experiments in animals indicated that the normal endothelial cell found lining the liver sinusoids has little if any Factor VIII fluorescence. Endothelial cells found lining larger vessels on the other hand demonstrated a striking fluorescence, as did experimentally transplanted mouse angiosarcomas. Conversely, mouse hepatic Kupffer cells, a second type of hepatic lining cell distinguished in histo logical cross section by engorgement with carbon particles, failed to demon strate positive fluorescence. An increase in antigenic Factor VIII in hepatic angiosarcoma endothelial cells as compared to the normal, led us to believe that these cells have increased production or storage capacity for antigenic Factor VIII.
Objective
1. To study the Factor VIII fluorescence in human angiosarcomas, primary hepatocellular carcinomas, and normal livers.
Research Results
Examination of angiosarcoma liver demonstrated a significant fluorescence due to Factor VIII content in the malignant cells of the liver sinusoids. An intermittent pattern of fluorescence or the sinusoidal lining cells was seen. These cells were histologically identified as angiosarcomatous on hematoxylin and eosin ( H & E) staining of adjacent tissue. This type fluorescence was not seen in individuals with primary hepatocellular carinomas and a different pattern was seen in normal livers. These cells and their fluorescent pattern are illustrated In Figures 4 and 5. Figure 4 illustrates the H & E stained cells and Figure 5 their Factor VIII fluorescence.
CMA 003028
TABU 12
DISTRIBUTION OF HLA-B15 ANTIGEN AMONG WORKERS WITH AND WITHOUT CHEMICAL RELATED LIVER DISEASE
(PALLET PLANT COHORT)
Clinical Diagnosis
29
TABU 13
DISTRIBUTION OF HU-B15 ANTIGEN AMONG WORKERS WITH AND WITHOUT CHEMICAL RELATED LIVER DISEASE
(MAIN PUNT COHORT)
Clinical Diagnosis
N--29 N-526
___ normal 1
_ CL I 4
LD 3
_-NORMAL Cl I LD
65 0 3
3 99
430
Total 4
13 12
C) (25) (31) (25) Total 49S
(Z) (15)
2 13
E IT (0) (13)
TABU 14
OCCURRENCE OF HU-315 AMONG CHEMICAL. WORKERS WITH AND WITHOUT CHEMICAL LIVER INJURY
Clinical Diagnosis
HORMAI
65
-- CLI
4
430
Total 495 (Z) (13)
11
15 (27)
N-538 LD BOTH 6 10
22 33
28 43 (21) (23)
CMA 003027
(2) The use of tu."or antigens for the detection of developing angio sarcoma, although a provocative possibility, is far too non-specific in its present stage of development to provide any reasonably useful means cf detecting early cancer development. Until there is better evidence that tumor antigens provide sufficient specificity to prevent cross reactivity with other tissue materials, this approach will not appear to be a clinically useful one.
(3) The present data suggest that the HLA-815 antigen may reflect an increased susceptibility to liver injury,' especially of chemically-induced origin. Confirmation of these findings and the determination of the effec tiveness of this marker in screening those with Increased susceptibility to chemical liver injury must yet be determined by prospective study.
(4) The leukocyte adherence inhibition test, unfortunately, was not adequate in its technical development nor sufficiently reproducible to be useful as a screening test for either colon cancer or liver angiosarcoma.
All of the above immunological studies, with the possible exception of HLA marker, have provided little supportive evidence that chemical injury interferes with human immunocompetence as determined by our present methods of study. Therefore, studies of the immunological system for screening purposes appear to be of little, if any, value in the early identification of chemical injury or disease.
(5) The identification of Factor VIII production by human and anis|^ angiosarcoma tumors provides further evidence for the need to develp screei^B methods to detect endothelial rather -than hepatocytlc cell injury cr dysfunction since these are the cells of origin that malignantly transform when exposed to vinyl chloride and other agents such as arsenic.
References
Foley, E.J. (1953) Antigenic properties of methylcholanthrene-induced tumors in mice of the strain of origin. Cancer Research 13:835-837.
Halllday, W.J., Halliday, J.W., Campbell, C.B. et al. (1974) Specific immunodlagnosis of hepatocellular carcinoma by leukocyte adherence inhibition. British Medical Journal, 18,-.349-352.
Hellstrom, I., Hell Strom, K.E., Sjogren, H.O. and Warner, S.A. (1971) Demonstration of cell-mediated immunity to human neoplasms of various histological types. International Journal of Cancer. 7,:1-16.
Mulvihill, J.J. (1976) Host factors In human lung tumors: An example of co-genetics in oncology. Journal National Cancer Institute, 57:3-6.
MA 003030
33
Prehn, R.T. and Maine, J.M. (1957) Immunity to methylcholthrene-induced
sarcomas. Journal of the National Cancer Institute, 16:No. 6, 769-
* 775>
--
Scott, 8.B., Rajah, S.M. and Losowsky, M.S. (1977) Histocompatibility antigens in chronic liver disease. Gastroenterology, 72:112-125.
Terasaki, P.I., Bernoco, D., Park, M.S., et al. (1978) Microdroplet testing for HLA-A, -B, -C, and -0 antigens. American Journal of Clinical Pathology, 2^:103-119.
Thompson, D.M.P., Gold, P., Freedman, S.O. and Shuster, J. (1976) The isolation and characterization of tumor-specific antigens of rodent and human tumors. Cancer Research, 36:3518-3525.
Vankey, F,, Stjernsward, J. and Nilsonne, U. (1971b) Cellular immunity to
human sarcoma. Journal of the National Cancer Institute, 46:1145-
1151.
--
World Health Organization Report (1977) Histocompatibility testing. Bodmer, W. (ed.), Munksgaard, Copenhagen.
CMA 003031
PROGRAM B
STUDY OF HEPATIC BIOCHEMICAL AND ENZYMATIC SYSTEMS FOR THE IDENTIFICATION OF VINYL CHLORIDE AND OTHER CHEMICAL INJURY IN CANCER DEVELOPMENT: ANIMAL AND HUMAN STUDIES; Investigators - J.T. Du, C.H. Tamburro and M.T. Tseng
ANIMAL STUDIES:
B1. Characterization Of Hepatic Enzyme Changes In Rats With Prolonged Vinyl Chloride Exposure: Decreased Glucose-6-Phosphatase Activity
B2. Morphological Alterations In Livers Of Rats Exposed To Vinyl Chloride
Background
Vinyl chloride has been shown to induce an identical malignancy In both animals and man. Vinyl chloride-induced liver cancer in animals, therefore, provided an excellent model for the study of chemically-Induced carcino genesis. The rat model provides the opportunity to further elucidate the mechanism and the pathogenesis of this particular chemical agent, whose major oxidation occurs in the hepatocytes (primary liver cells) while inducing a malignant transformation in an adjacent, different cell type (endothelial lining cell of the sinusoids). Vinyl chloride had been shown to cause angiosarcoma and primary hepatocellular carcinoma in laboratory animals (Maltoni, 1975, 1976), and angiosarcoma in man (Creech and Johnson, 1974). However, little was known regarding the biochemical changes that vinyl chloride mediated to Induce hepatocellular injury and subsequent malignant transformation of the mesenchymal cells.
Enzymatic alterations in primary liver parenchymal cell cancers (hepato cellular carcinoma, hepatoma) have been studied extensively. Weber and Convery (1966) and Weber and Lea (1967) proposed that there Was a^ biochemical pattern which could be related to the biological behavior of neoplastic cells. Using a spectrum of hepatomas with different growth rates, a basis for underlying neoplastic cell transformation was proposed as being related to the cell's progressive- alterations in the molecular pattern which led to progressive increases in the growth rate of the tumors. Figure 1 outlines the pathways.
34 CMA 003032
FIGURE 1
WEBER'S MOLECULAR CORRELATION CONCEPT OF NEOPLASIA
35
i
-- oiucoMowm
Key enzymes of glycolysis were shown to Increase while key enzymes In gluconeogenesls decreased with tumor growth. In addition, the pentose phosphate biosynthetic pathway, glucose-6-phosphate dehydrogenase (Weber and Morris, 1963) and transaldolase (Heinrich et al., 1974) were shown to be Increased In all hepatoma studies. Furthermore, the activity of phosphorlbosylpyrophosphate (PRPP) synthetase and glutamine PRPP aminotransferase, the first two enzymes channeling rlbose-5-phosphate Into purine, DNA and RNA synthesis were also Increased. The PRPP sythetase was Increased In rapidly growing hepatomas and the transferase In all the hepatomas Irrespective of growth rates (Weber et al., 1975). Oecreased enzyme activity was observed at an early stage of carcinogenesis before the morphological signs of a tumor appeared In the liver, and the activity of enzymes dependent upon the rate of hepatoma proliferation correlated with progressive malignant transformation.
These findings and the lack of any long-term sequential studies of animals exposed to vinyl chloride directed us to our first three objectives.
Objectives
1. To determine the sequential hepatic enzymatic changes In animals chronically exposed to vinyl chloride and their correlation to con ventional clinical tests of liver function.
CMA 003033
36
2. To determine if these sequential enzymatic patterns, especially with regard to carbohydrate metabolism and nucleic acid synthesis, would correlate with vinyl chloride-induced liver injury and ultimate malignant transformation.
3. To correlate the sequential, morphological changes with these en zymatic findings.
Research Results
1. Characterization of Hepatic Enzyme Changes
Sprague-Oawley adult male rats were chronically exposed to vinyl
chloride. The initial studies characterized the metabolic alteration in the
liver by studying various organelle enzyme markers which included glucose-e-
phosphatase (microsomal), cytochrome oxidase (mitochondrial) and glucose-6-
phosphatase dehydrogenase (cytosol). In addition, standard serum biochemical
clinical liver studies of the liver (liver "function" tests) were performed
including aspartate aminotransferase (SGOT), alanine aminotransferase (SGPT),
alkaline phosphatase, lactic acid dehydrogenase, total protein, and bili
rubin. Additional studies of subcellular enzymes related to nucleic acid
synthesis--glutamine PRPP aminotransferase, and glycolysis--phosohofructo-
kinase were done.
vivo protein synthesis was assessed by ^H-leucine
incorporation.
The results of these studies illustrated that rats exposed to high chronic doses of vinyl chloride had a 25% lower activity of glucose-6-phosphatase, a key enzyme for gluconeogenesis after about 71 hours of exposure and a 50-100% increase in glucose-6-phosphate dehydrogenase, a rate limiting enzyme in the pentose pathway, after 84 hours of exposure.
These studies demonstrated that (a) metabolic alterations in the liver cell are induced by vinyl chloride exposure, (b) gluconeogenesis is altered as reflected by a lower glucose-6-phosphatase and a higher glucose-6-phosphatase dehydrogenase activity, and (c) that these changes occur in,a fashion similar to the lower gluconeogenic and higher pentose shunt activity of hepatomas. Although this could result in an enhanced production of PRPP and ultimately more nucleic acid synthesis, our studies of PRPP did not document this as a subsequent finding. These enzymatic changes, although similar to the biochemical changes seen in rapidly growing primary hepatocellular carcinomas, most likely reflect liver cell adaptation to vinyl chloride exposure but do not appear to significantly increase DMA synthesis. In addition, these changes were sufficiently limited so as not to be reflected by circulating enzyme levels traditionally used for the detection of clinical hepatocellular injury (Figure 2).
CMA 003034
CONVENTIONAL CLINICAL BIOCHEMICAL STUDIES IN RATS EXPOSED TO VINU CHLORIDE ____ CONTROL
VC TREATED
SOFT IU/1
SOOT
1U/I
37
l OH 1U/I
TOTAL
PROTON OMMI
FIGURE 2
HOURS OP VINU CHLORIDE EXPOSURE
2. Morphological Alterations: Light and Electron Microscopic Assessment
Sequential morphological assessment was performed In both of the chronic experiments utilizing light and electron microscopy.
The enzymatic findings discussed In B1 and subsequently In B3 were associated with light microscopic findings which showed a marked Increase In liver cell polyploidy, double nucleated cells and areas of focal hepato cellular hyperplasia. There was no evidence of hepatocellular Injury, necrosis, or Increased fibrosis. The morphological changes seen, however, reflect an Increased liver cell regeneration which was not measurable by the techniques used to measure DNA synthesis In our experiments.
The electron microscopic changes demonstrated a proliferation of the smooth endoplasmic reticulum without evidences of changes In the hepatocytlc cell, cell membrane, nucleic acid or rough endoplasmic reticulum structures.
CMA 003035
38
There was no evidence of increased collagen deposition in the space of Disse which has been reported by others during terminal or final stages of angio sarcoma development in animals.
83. Alterations in the Oxidizing and Detoxifying System of the Rat Liver After Prolonged Exposure to Vinyl Chloride.
Background
Vinyl chloride metabolism had been shown to be blocked at low dosage levels (50 ppm) by inhibiting the alcohol dehydrogenase system and at higher levels (200 ppm) by metabolism via the microsomal mixed function oxidase (MFO) system (Hefner et al., 1975, Bolt et al., 1975). Vinyl chloride's major metabolites, chlorooxirane and chloroacetaldehyde, have been identified as probable ultimate carcinogens (Barbin et al, 1975; Van Duuren, 1975; and Jaeger et al., 1974). Further studies (Elmore et al., 1976; Malaveille et al., 1975; McCann et al., 1975) demonstrated the mutagenic activity of chloro oxirane and chloroacetaldehyde on microorganisms and the nonmutagenicity of chloroethanol and chloroacetic acid, other metabolites of vinyl chloride.
Detoxification of these metabolites was reflected by a reduction In non protein sulfhydryl content of the liver (Hefner, 1975) and tracer studies showing major urinary metabolites of vinyl chloride to be N-acetyl-S-hydroxyethylcysteine and thiodiglycolic acid (Vlatanabe et al., 1976). The proposed metabolic fate of vinyl chloride is illustrated:
Cl CH - CJ^ Cv c)
DETOXIFICATION WITH GLUTATHIONE
Cl CHjCHjOH
6$ CH^CHjOH
N"A-S-(2-HYDROXY
(CHLOROOXIRANE)
Cl CHjCHO Cl CHjCOOH
GSjCHjCHO
GS CH^COOH THIODIGLYCOLIC ACID
(CHLOROACETIC ACID)
In these experiments, the enzymes studied related to vinyl chloride oxidation, included P.-450, NADPH-cytochrome-C-reductase and mixed function oxidase. Those enzymes related to detoxification Include non-protein sulfhydryl content (NPSC), glutathione content _(GSH), glutathione reductase (GR), glutathlone-epoxide-S-transferase (GEST, glutathione-E-transferase), and glutathione-aralkyl-S-transferase (GAST, glutathione A&B transferases).
CMA 003036
39
Objective
1. To determine the sequential changes of key hepatic oxidizing and detoxifying enzymes with prolonged vinyl chloride exposure.
Research Results
The oxidizing and detoxifying capability of rat liver cells during prolonged exposure to chronic high doses of vinyl chloride demonstrated a 25-50% higher activity of glutathione reductase, the enzyme which regenerates reduced glutathione to detoxify the metabolites of vinyl chloride. Although our acute and single vinyl chloride exposure studies demonstrated a decrease in the nonprotein sulfhydryl content (48%) similar to that reported by Hefner (1975), repeated or chronic exposure to higher levels showed a progressive increase which was statistically significant after 70 hours of exposure (Figure 3).
Glutathione-epoxIde-S-transferase (GEST) and glutathione-aralkyl-S-transferase (GAST), the enzymes capable of conjugating the toxic vinyl chloride metabolites, were significantly elevated following vinyl chloride exposure; glutathione recuctase (GR), the enzyme to regenerate glutathione, was also elevated significantly following vinyl chloride exposure (Figure 4).
a nOrmu. * vC ait air exit COntr&lS
Mm..
o morhal t ndi. . ur ixr coJriwLi
MMt..
FIGURE 3 CMA 003037
FIGURE 4
40
The oxidizing capability as reflected by cytochrome P-450, the major protein involved in vinyl chloride metabolism, however, was"reduced signifi cantly only after prolonged vinyl chloride exposure (Figure 3), supporting reports in vivo (Reynolds et al., 1975) and in vitro (Guengerich and StricklancIT T977; Ivanetich et al., 1977) that vThyT chloride metabolites destroyed P-450. No differences were found in the conventional clinical serum biochemical tests or in other cellular enzyme studies (cytochrome-C oxidase, NADPH-cytochrome-C-reductase and mixed function oxidase).
These changes seem to reflect early hepatic cell adaptation to chronic vinyl chloride exposure by increasing their capacity for detoxification and decreasing their capability to further metabolize vinyl chloride into its toxic intermediates--both provide a means of natural defense to a toxic substance. This entire detoxifying sequence is shown in Figure 5 as a composite of the detoxifying enzyme changes over a prolonged period of exposure.
FIGURE 5 It is interesting to note that there is an earlier increase in the GEST trans ferase than the GAST transferases with prolonged exposure. This may reflect an earlier (in time) need for adaptation to excessive production of the epoxide and subsequently the accumulation of the aldehyde metabolite. Whether this reflects the maximum adaptability as indicated by a leveling off of enzyme after 200 hours, or whether these changes reflect an adaptation to
CMA 003038
41
prevent cellular injury as well as prevent orimary hepatocellular malignant transformation would require even longer sequential studies for confirmation; these were beyond our time constraints.
B4. Oxidizing and Detoxifying Ability of liver Mesenchymal or Parenchymal Cells In the Metabolism of Xenobiotics.
Background
Even though the malignant transformation induced by vinyl chloride occurred in the mesenchymal cells of the liver (endothelial cells), all meta bolic studies up to this time had been directed at the liver as a whole or to the parenchymal cell--the hepatocyte. There had been no differentiation between the oxidizing capability of the hepatocytes that demonstrated injury and the endothelial cells which were malignantly transformed. Little was also known regarding the variable ability of these two cell types in the removal of the ultimate carcinogens or active metabolites. Therefore, our next set of studies was directed toward the ability of two different cell types' to metabolize vinyl chloride.
Objective
1. To study the comparative ability of the hepatocytes versus the mesen chymal cells to metabolize vinyl chloride and determine the detoxi fying capability of the various liver cell types.
Research Results
Enzymatic studies of the detoxifying activities of the subcellular fraction of liver cells, both hepatocytic and mesenchymal included the study of GEST, GAST, GR, as well as -450 and mixed function oxidase capability of the various cell fractions. ~The effectiveness of the isolation of the hepatocytes and mesenchymal cells was confirmed by studying pyruvate kinase activity.
Mesenchymal cells were shown to have about half the GEST activity, 72 of the GAST activity, less than half of the microsomal function oxidase activity, and 732 of the GR capability compared to the hepatocytes. The activity per million cells indicated that the nonhepatocytes had about 1/70 MFO activity, 1/65 GEST activity, 1/500 GAST activity, and 1/45 GR activity. These results demonstrate that the nonhepatocyte has significantly less capability in both the activation and detoxification of vinyl chloride and other xenobiotics. The data supports the hypothesis that the endothelial cells have a more limited capability to detoxify vinyl chloride metabolites and that this limited capability provides a greater possibility for DNA injury and subsequent malignant transformation. Again, unfortunately much longer
CMA 003039
42
experimental studies would be needed to eventually validate this hypothesis (Du et al., preprint attached in Appendix).
Relevance to Industry
(1) These chronic sequential studies are highly relevant to the chemical industry's environmental health problems. The sequential, biochemical changes that occur in the carbohydrate metabolism of the liver hepatocytes reflect adaptation of the liver cell to chemical exposure. This is further reflected by the histological changes which show polyploidy, double nucleated cells and areas of focal hyperplasia. As the clinical studies in this report will subsequently show, these changes are characteristic of chemical injury but do not necessarily reflect premalignancy. This would be consistent with the enzymatic studies failing to demonstrate any evidence of increased nucleic acid synthesis which is seen in the premalignant hepatoma studies of Weber and others. The important fact is that these changes cannot be detected by the standard federally-required biochemical studies, because these are directed solely at the hepatocyte. The hepatocyte may become injured but it does not usually malignantly transform.
(2) The oxidative and detoxifying results of this study demonstrate that the hepatocyte progressively adapts its ability to remove and detoxify .the active metabolites. This occurs without evidences of hepatocellular injury, at least up to what would be equivalent to 6-20* of the working years of a chemical worker. The studies also emphasize the fact that at very high exposures, the detoxifying system is adaptive and the oxidizing system's capacity is reduced, thereby providing a relative defense against continued formation of toxic metabolites.
(3) The massive ability of the hepatocyte to oxidize as well as detoxify the active metabolites of vinyl chloride can well explain why there is no hepatocellular carcinoma development In humans with vinyl chloride exposure. A markedly reduced ability of the nonhepatocyte to detoxify the metabolites while still having the capacity to oxidize vinyl chloride into its active metabolites would support the higher probability of this cell becoming malignantly transformed. Since all clinical screening studies are directed toward the hepatocyte, these animal studies emphasize the Insensitiveness of clinical biochemical studies to correctly identify early fn3ury In the more susceptible cell, i.e., endothelial cell. More sensitive indicators of nonhepatocytlc cell injury or dysfunction are needed for the detection of early chemical injury. These indicators must take into account the function of both types of liver cells.
/
(4) The morphological findings described in the animal experiments con firm earlier observations regarding the earliest histological manifestations of vinyl chloride injury. They support our clinical observations that these lesions can be used to identify chemical injury. Program D, on the morphormetric and histological analysis details the clinical results found in humans.
CMA 003040
HUMAN STUDIES;
43
B5. Effectiveness of Indocyanine Green Clearance in the Detection of Liver Injury.
Background
The increasing concern over the potential health hazard of synthetic chemicals in the occupational environment has led the government to require, and many industries to establish, medical laboratory screening programs for their employees. The primary objectives of these screening programs is to identify potential work-related disease, so that intervention may reduce disability, morbidity, and mortality. Most screening studies are directed toward the detection of abnormalities in certain body systems. The specific tests used are most often selected on the basis of medical experience in symp tomatic or hospitalized populations. Prior experiences utilizing non specific, multi-phasic health screening have not proven to be effective in this area. The effectiveness of standard medical testing used predominately in asymptomatic individuals with subclinical low-grade disease--both work and non-work related--had not been determined. This study assessed the effec tiveness of using clearance studies of anionic dyes in the detection of liver injury in such Individuals.
Objective
1. To determine the effectiveness of ICG clearances in detecting hepatic injury.
2. To compare ICG sensitivity and specificity to standard clinical biochemical screening in the detection of liver injury.
Research Results
The study group (cohort) consisted of 969 male employees who were tested between June 1, 1976 and May 31, 1977 with standard biochemical studies of the liver which included alanine aminotransferase (ALT/SGPT), aspartic aminotrans ferase (AST/SGOT), gamma glutamyl transpeptidase (GGTP), alkaline phosphatase (AP), and total bilirubin (TB). In addition, these employees were also screened by ICG clearances at the 0.5, 2.5, and 5.0 mg/kg doses, and by two more specific liver enzyme tests (isocitrlc dehydrogenase [ICO] and sorbitol dehydrogenase [SDH]). This main cohort was divided Into a "standard" and a "non-standard" population for purposes of analysis. The division was based upon the best medical opinion. The "standard" group demonstrated no clinical evidence of significant medical disease--occupational or non-occupational in origin, and "non-standard" included all the others.
A subcohort of 120 individuals who had undergone liver biopsies for medical reasons, whether related to work or not, were also studied. This subcohort population was divided into those individuals with and without
CMA 003041
44
histological evidence of liver injury, and the former further subdivided into those with and without histological characteristics of chemical injury (see Program 02).
All employees had individual work histories and rank-ordered exposure Indices for 22 different chemicals used within the work place.
The GGTP provided the highest positive predictive value as a screening test for non-standard individuals (population with medical disorder). It also provided the highest sensitivity and specificity sum among the 5 most frequently abnormal tests (AST/SGOT, ALT/SGPT, AP, ICG); 2 other tests also had high predictive values--the indirect bilirubin, due to the high number of congenital indirect hyperbilirublnemic individuals, and the triglyceride levels, most likely reflecting differences in age, weight, and diabetic status in the non-standard population.
The ICG clearance (0.5 mg/kg) espressed as mean t 1/2 in minutes (min.) demonstrated differences not only between standard and non-standard population but also differences between those with high and low mean exposure to vinyl chloride (Table 1).
TABLE 1
INDOCYANINE CLEARANCE IN A COHORT INDUSTRIAL POPULATION
SUBGROUP
STANDARD LOW VC EXPOSURE
`MEAN
NO. MIN. 90S 100Z 662 2.9 2.0-3.8 1.8-4.8 453 2.9 1.8-4.0 1.7-4.3
NON-STANDARD
HIGH VC EXPOSURE
257 466
3.4 2.1-5.6 2.0-6.6 3.1 2.1-4.4 1.9-4.8
The biochemical tests which best correlated with the presence of hepatic disease In the chemical workers with clinical evidence of liver disease were ALT (SGPT), GGTP, alkaline phosphatase, and ICG clearance (i.e. these were'the tests with the highest sensitivity in detecting latent liver disease). Sensi tivity alone, however, is not an adequate indicator of a test's screening value, especially when used in asymptomatic individuals. More appropriate evaluation of the screening abilfty of the tests requires that both sensi tivity and specificity be determined, i.e., identify the diseased individuals and correctly exclude the non-diseased individuals. The sensitivity and
CMA 003042
45
spacificity of the 4 most sensitive biochemical screening tests and the ICG clearances (all.doses) demonstrated that GGTP although the most sensitive is the least specific; AP has the highest specificity but the lowest sensitivi ty. ICG clearances, even at the low dose, clearly remain the best test, i.e., in combined sensitivity and specificity for screening and detecting individu als with subclinical liver disease (Table 2 a,b,c).
TABLE 2
A BC
SENSITIVITY MO SPECIFICITY OF INDOCYANINE GREEN CLEARANCE
SENSITIVITY AND SFECIFICITY OF inOOCTJUlINE GREEN OEAMNS
io. t:sto 1500
ICG 1.3 k/ko
3iJT
KtBIOAL AtUISWT
ICG 3.S **/
(*> (*)
(*) MS
190
(-) 3
1923
TOTAL
SIS mu
2939
(*) '
UtT (*) 93 .lOICAL Amimur (-) 19
(-> 26 396
ttMtnvrrr; 35,2 iMCirtetTT: 35,61
MWITIVITT! 93/73 $1.61 mcmcm: J9S/910 96.31
Total
73 91Q 963
SENSITIVITY MO SPECIFICITY OF tNOQCYA.lt.IE GrESI CLEARANCE
Jl" NOICAL
ICS 3.3 ro/ui
iil lil
(> 71
6
Ajmsnnnt (.)
StMtTtvrnr; 73/3* 92.2 SncrPtetTr: 11/92 90.3
Tnm
M
g
126
In addition ICG clearance demonstrates excellent correlation with the histo logical presence of liver disease and liver cancer (Figure 6).
UYCT HISTOLOGY AMO DYE CLEARANCE AMONG VINYL CHLCrtOC(VC) WORKERS
FIGURE 6
The subcohort blopsled population was additionally studied with regard to the sensitivity and specificity of the screening tests, the specific histo logical interpretation of the liver biopsy, and the relationship to vinyl chloride exposure. All blopsied individuals were subclassified into three groups: those with histological evidence consistent with chemical liver
CMA 003043
46
injury, those with histological evidence of liver disease without evidence of chemical injury, and those with normal liver biopsies. Each group was then evaluated regarding the sensitivity and specificity of the biochemical tests and their total exposure to vinyl chloride based on a rank ordered scale.
Analysis of the subcohort biopsied group's work histories demonstrated that those individuals with chemical liver injury had the highest average rating for vinyl chloride exposure and were best identified by screening with ICG clearance tests.
B6. The Assessment of Bile Acids Vs. Indocyanine Green (ICG) Clearances in the Detection of Liver Injury in a Chemically-Exposed Worker Population
Background
Since highly sensitive and specific screening tests for the detection of latent hepatic injury were needed, studies were conducted to determine whether bile acid clearances could be utilized to detect occupationally-related hepatic injury. Bile acids are naturally occurring steroids which are synthesized and removed solely by the liver. These substances, in contrast to synthetic anionic dyes such as indocyanine green, have been reported to provide equal if not better, sensitivity in the detection of liver disease. The development of radioimmunoassays for bile acids provided an economical means of determining whether these natural substances could be used as effective screening measures in subclinical liver disease. Studies were conducted to determine the relative effectiveness of bile acid levels vs. ICG clearances in the detection of subclinical liver disease.
Objective
1. To determine the effectiveness of bile acid clearance in the detection of subclinical liver injury2
2. To compare bile acids to ICG clearance in identifying chemical and non-chemical liver injury.
Research Results
A subcohort (64) of the worker population who had liver biopsies done for medical reasons ano had both ICG clearances and serum bile acids--chalylglycine (CG) and conjugates of cholic acid (CCA)--performed, were studied. These individuals were subdivided on the basis of the histological features of their biopsies into individuals with chemical liver injury (CLI), individuals with non-chemical liver disease (NCLD), and individuals with no histological abnormalities (NBX). The mean plus or minus S.E.M. for ICG, CG and CCA in the CLI, NCLD, NBX, and a non-biopsied normal group are shown in Table 2.
CMA 003044
TABLE 2
CORRELATION OF LIVER EICPSY WITH BILE ACID LEVELS AND ICG CLEARANCE
ICG(W CO.) as/kf)
CG Cu*/dl>
CCA (uf/dl)
CLI 4.2 i 0.6
95.2 * 28.3
39.7 t 29.3
NCLD 3.2 1 0.1
27.3 i 4.4
25.3 i 4.5
N8X 3.3 i 0.2
34.60+ 7.1
52.5 i 26.6
NON BIOPSIES N0RJ1AL
3.1 i 0.01
14.9 1 0.9
18.7 1 1.2
47
Analysis of variance (on log transform data) showed significant differences for ICG clearance for the three blopsied groups and for all four groups. Values for the CLO were significantly different from the ICGs for the normal, but showed no significant difference between the NCLD and the N8X group. Analysis of variance for ICG clearance was not as discriminating for the 3 blopsied groups. ICG clearance gave a better separation (sensitivity) of the normal vs. abnormal at the 95 percentile level for the normal population in the serum bile acids.
This preliminary analysis, therefore, shows that fasting serum bile acids hold promise as a potential detector of early liver dysfunction, particularly chemically*Induced, In those Individuals who are asymptomatic. This test should be further Investigated to determine how this natural substance might be more effectively utilized as a screening technique. Bile acids can be taken orally for clearance study and are not limited to Intravenous route as is the case for synthetic anionic dyes such as ICG. Studies In this area continued to be pursued In similar populations.
Relevance to Industry
These clinical study results provide the best scientific basis upon which to recommend effective medical screening tests for the detection of occupationally-related injury to the liver. The results also provide sound scientific reasons for recommending modification of presently required federal testing In environments utilizing potentially hepatotoxic agents.
Although synthetic anionic dye presently provides the best means for detecting early latent liver injury, it is limited by the need to be injected (an invasive procedure). Although reactions to the injection of this dye have been minimal. It does present barriers to voluntary worker compliance. Therefore, development of a screening test which can effectively determine
CMA 003045
48
overall hepatic function, can be given orally, and is a nonsynthetic, normal biological constituent approaches the most ideal test for screening. Bile acid clearance could be the least invasive and therefore the most acceptable method to test asymptomatic individuals undergoing screening. The bile acid studies described above are the basis for recommending its use in future screening. The standardization of these bile acid test techniques, however, requires further careful validation so that specific recommendations regarding their use will provide the most accurate delineation between those with disease and without disease and those with occupationally-related disorders versus naturally-occurring ones.
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Bolt, H.M., Kappus, H., Butcher, A., and Bolt, W. (1975). Metabolism of vinyl chloride. Lancet 1, 1425.
Creech, J.L., and Johnson, M.N. (1974). Angiosarcoma of liver in the. manufacture of polyvinyl chloride. _0. Occup. Med. 16, 150-151.
Creech, J.L., Makk, L., Whelan, J.G., Jr., and Tamburro, C.H. Hepatotoxicity among polyvinyl chloride production workers during first year of surveillance program. Gastroenterology 67, 786 (1974).
Du, J.T., and Tamburro, C.H. (1976). Decreased glucose-6-phosphatase activity in liver in vinyl chloride exposed rats. Fed. Proc. 35, 329.
Du, J.T., and Tamburro,C.H. (1978). Elevated glutathione content, glutathione-S-transferase and glutathione reductase in liver of rats exposed to vinyl chloride. Fed. Proc. 37, 1545.
Du, J.T., Sandoz, J.P., Tseng, M.T., and Tamburro* C.H* (1979). Biochemical alterations in livers of rats exposed to vinyl chloride. _J. Toxicol. Environ. Health 5, 1119-1132.
Elmore, J.D., Wong, J.L., Laumbach, A.D., and Streips, U.N. (1976). Vinyl chloride mutagenicity via the metabolites chlorooxirane and chloroacetaldehyde monomer qydrate. Biochem. Biophys. Acta 442, 405-419.
Fortwengler, H.P., and Tamburro, C.H. (1975) Use of- dye clearance in the detection of hepatocellular injury among vinyl chloride workers. Clin. Res. 23, 264A.
Green, T., and Hathway, D.E. (1977). The chemistry and biogenesis of S-containing metabolites of vinyl chloride in rats. Chem. Biol. Interact. 17, 137-150.
CMA 003046
49
Greenberg, R.A., and Tamburro, C.H. (1981). Exposure indices for epi
demiological surveillance of carcinogenic agents in an industrial chemical environment. _J. Occup. Med., 23. 353-358.
Greim, H., Bonse, G., Radwan, Z., Reichert, 0., and Henschler, 0. (1975). Mutagenicity in vitro and potential carcinogenicity of chlorinated ethylenes as a function of metabolic oxirane formation. Blochem. Pharmacol. 24, 2013-2017.
Guengerich, F.P. and Strickland, T.W. (1977). Metabolism of vinyl chloride: Destruction of the heme of highly purified liver
microsomal cytochrome P-450 by a metabolite. Mol. Pharmacol. 13, 993-1004.
Hefner, R.E., Watanabe, P.G., and Gehring, P.0. (1975). Preliminary
studies of the fate of inhaled vinyl chloride monomer in rats. Ann. N.Y. Acad. Sci 246, 135-148.
Heinrich, P.C., Morris, H.P., and Weber, G. (1974). Increased phosphoribosylpyrophosphate synthetase activity in rapidly growing hepatomas. FEBS Lett. 42, 145-148.
Ivanetich, K.M., Aronson, I., and Katz, I.D. (1977). The interaction of vinyl chloride with rat hepatic microsomal cytochrome P-450 in vitro. Blochem. Biophys. Res. Conroun. 74, 1411-1418.
Jaeger, R.J., Connolly, R.8., and Murphy, S.O. (1974a). Effect of 18 hr. fast and glutathione depletion on 1, 1-dichloroethylene-induced hepatotoxlcity and lethality in rats. Exp. Mol. Pathol. 20, 187-198.
Jaeger, R.J., Reynolds, E.S., Connolly, R.B., Moslen, M.T., Szabo, S., and Murphy, S.D. (1974b). Acute hepatic injury by vinyl chloride in rats pretreated with phenobarbital. Nature (London) 252, 724-726.
Kappus, H., Bolt, H.M., Buchter, A., and Bolt, W. (1976). Liver microsomal
uptake of 14C-vinyl chloride and transformation to protein
alkylatinq metabolites in vitro. ToxIcoL. Appl. Pharmacol. 37,
461-471.
"~
Malavellle, C., Bartsch, H., Barbin, A. Camus, A.M., and Montesano, R. (1975). Mutagenicity of vinyl chloride, chloroethylene oxide, chloroacetaldehyde and chloroethanol. Biochem. Biophys. Res. Commun. 63, 363-370.
Maltoni, C., Lefemine, G., Chieco, P. and Carretti, D. (1974). Vinyl
chloride carcinogenesis: current results and prospective. Medicine Oel. Lavoro. 65, 421-444.
Maltoni, C., and Lefemine, C. (1975). Carcinogenicity bioassays of vinyl chloride: Current results. Ann. N.Y. Acad. Sci. 246, 195-218.
CMA 003047
50
McCann, 0., Simmon, V., Streitwieser, D., and Ames, 8.N. (1975). Muta genicity of chloroacetaldehyde, a possible metabolic product of 1,2dlchloroethane, chloroethanol, vinyl chloride and cyclophosphamide. Proc. Nat. Acad. Sci. USA 72, 3190-3193.
Reynolds, E.S., Moslen, M.T., Szabo, S., and Jaeger, R.J. (1975). Vinyl chloride-induced deactivation of cytochrome P-450 and other components of the liver mixed function oxidase system: An in vivo study. Res. Coranun. Chan. Pathol. Pharmacol. 12, 685-694.
Tamburro, C.H., Makk, L., and Popper, H. (1979). Early hepatic histological alterations among chemical (vinyl monomer) workers. Gastroenterology 77, A33.
VanOuuren, B.L. (1975). Possible mechanism of carcinogenic action of vinyl chloride. Ann. N.Y. Acad. Sci. 246, 258-267.
Watanabe, P.G., Hefner, R.E., Jr., and Gehring, P.J. (1976a). Vinyl chloride-induced depression of hepatic non-protein sulfhydryl content and effects of bromosulphalein (BSP) clearance in rats. Toxicol. 6,
1-8.
Watanabe, P.G., McGowan, G.R., and Gehring, P.J. (1976b). Fate of 14C-vinyl chloride after single oral administration in rats. Toxicol. Appl. Pharmacol. 36, 339-352.
Watanabe, P.G., Zempel, J.A., Pegg, D.G., and Gehring, P.J. (1978). Hepatic macromolecular binding following exposure to vinyl chloride. Toxicol. Appl. Pharmacol. 44, 571-579.
Weber, G. (1974). The molecular correlation concept, ^n The Molecular 81o1ogy of Cancer, ed. H. Busch, pp. 487-521. New York:Academic.
Weber, G. and Convery, H.J.H. (1966). Insulin: Inducer of glucose-ephosphate dehydrogenase. Life Sci. Jj, 1139-1146.
Weber, G. and Lea, M.A. (1967). The molecular correlation concept. In Methods in Cancer Research, ed. H. Busch, vol. 2, pp. 523-578. Hew York:Academic.
CMA 003048
PROGRAM C
STUOY OF GLYCQSAMINQGLYCAN CHANGES IN THE DETECTION OF HEPATIC FIBROTIC INJURY IN CHEMICAL EXPOSURE AND HEPATIC CANCER DEVELOPMENT; Investigators - C.E. Kupchella and R. Warick
ANIMAL STUDIES:
Cl. The Study of Glycosaminoglycan Changes in Livers of Animals Bearing Metastasizing Hepatomas
C2. Significance of Tissue Glycosaminoglycan Elevations In Hepatic Fibrosis, Necrosis, and Regeneration
HUMAN STUDIES:
C3. Characterization of Glycosaminoglycan Patterns in Humans with Angiosarcoma
C5. Characterization of Glycosaminoglycan Patterns in the Identification of Chemical and Nonchemical Injury of the Liver'
C4. Evaluation of Glycosaminoglycan Analysis of Urines of Chemically- Exposed Workers
Background It is well established that glycosaminoglycans (GAGs) are Involved in wound healing and scar formation. Although it is less certain what role they play, it is known that certain GAGs are elevated In malignant tumors including hepatic tumors, and it has been postulated that GAGs may be impor- tant determinants of tumor-cell properties. A number of laboratories. Including ours, have established that urinary GAG excretions may serve as markers in the pathogenesis of chemical Injury, fibrosis, and cancer. Despite the fact 'that urinary GAG analyses have long been used clinically to detect and diagnose genetically-determined metabolic disorders of GAG metabolism, a
51
CMA 003049
52
systematic evaluation of the usefulness of urinary GAG patterns in the detec tion and diagnosis of acute and/or chronic, necrotic and/or fibrotic liver injury--or cancer--has never been made. Studies were begun to determine the practical utility of tissue and urinary GAG analysis in the detection and diagnosis of chemically*induced liver injury and. cancers.
Objective
In Animals:
1. To determine the relationship between GAG patterns in tumor tissue (and urine) in animals with fast versus slow growing and in metasta sizing versus non-metastasizing, chemically-induced, transplantable, hepatocellular tumors. (As an initial means of exploring the func tional role of GAGs known to be elevated in hepatic cancer).
2. To determine the sequence of GAG changes (In tissue, urine and blood) associated with the onset of experimentally-induced fibrotic injury with special attention to any change coinciding with the transition from reversible to irreversible fibrosis.
3. To determine the degree to which chemically-induced necrosis of tire liver results in altered urinary GAG excretion and confirm changes seen in tissue in earlier studies.
In Humans:
4. To compare the relative accuracy of the common methods of evaluating urinary GAGs and find the least expensive and least time-consuming method of urinary GAG analysis able to give good specificity and sen sitivity.
5. To repeat in a double-blind clinical trial the evaluation of the ability of urinary GAG analysis to correctly identify active liver disease.
6. To evaluate urinary GAG patterns in groups of alcoholics with active liver Injury over a time period.
7. To compare liver tissue and urinary GAG patterns In patients (a) with alcohol-injured livers, (b) hepatic angiosarcoma, (c) primary hepatocellular tumors, (d) livers with metastatic cancer, and (e) chemically-induced hepatitis and cirrhosis.
Research Results
In Animals:
Livers of animals bearing metastasizing hepatoma (5123tc) have 10-fold greater concentrations of a non-sulfated, neutral, uronic acid-positive
CMA 003050
53
material than is found in the livers of animals bearing two others, non-metastasizing hepatomas (4).
Heparan sulfate and hyaluronic acid levels--but not heparin--are 3-4
times higher in experimentally transplanted hepatomas than in normal liver and
urinary excretion reflects both the tumor GAG composition and the size of tumors (4, 8).
Hepatic necrosis is accompanied by significant tissue GAG elevations but hepatic regeneration is not (5).
Heparan sulfate (a type of GAG) is elevated in hepatic tissue undergoing experimentally induced fibrosis and heparan sulfate is elevated in the urine of experimental animals (3).
In Humans:
Human hepatic angiosarcoma and flbrotic liver disease are accompanied by elevated tissue GAGs (1).
The GAGs in the angiosarcomatous tumor tissue are different from those in fibrotic tissue adjacent to the tumor (2).
Angiosarcoma and hepatoma patients have characteristic urinary GAG pat terns--patterns not found in normal controls (2).
Gross (non-fractionated) urinary GAG determinations give a better indica tion of liver disease than ultrasound analysis. Exacting urinary GAG analysis (fractionated) is able to differentiated active from inactive liver disease
(7). Table 1 illustrates this for chrondrotin sulfate fraction.*
TABLE 1
prelimnary evaluation of me use * an exclusively ownniTi* SULFATE EXCRETION PATTERN AS A SCREENING TEST PON VINYL CHLORIDE - EXPOSURE - ASSOCIATED LIVER INJURY *
THT* ACSULT
VINYL CHLONIDf IXNIIM PLUS NON-ANRIOSARCOIUI L1VU INJURY
7J
- 2 29
StM 9 32
suhitivity 77.71 (95X LWtTi W.OI - 97.213 sncciaicity 90.SI (951 unit* 751 981)
*UN INK ANACTIONATIQN IN HHICH THC CNONONOItIN SULAATI ANACT ION IS AOSITIVC WT TMR HYALURONIC ACID ADO NtNARIN ANACT IONS ARC SOTH MtATIVt.
CMA 003051
54
Relevance to- Industry
These studies address the need for useful screening tests for liver injury--urine tests of the type evaluated obviously fit the ideal of being on-invasive, have no associated morbidity/mortality, and do not require "time off" from work to perform.
They could provide useful screening tests for early injury and for dif ferentiating active versus inactive disease.
GAG analysis may help assess methods of therapeutic intervention, i.e., the elucidation of the role of the GAGs in the pathogenesis of fibrotic liver disease and the identification of strategies by which fibrogenesis can be blocked and/or reversed.
Finally, they could provide useful means of identifying individuals at risk of chemical injury--by further characterization of GAG changes, one may be able to identify specifc injury due to chronic alcohol, chemical or other exposure agents in individuals with liver impairment.
References
1. Kupchella, C. 0., and Tamburro, C. H., (1978). Urinary and Tissue Glycosaminoglycans patterns in angiosarcoma and other vinyl chloride exposure associated liver Injury In: Detection and Prevention of Cancer. H.. Nelburgs, Ed., Part 1, Vol. 1, Marcel dekker, Inc., Hew fork.
2. Curran, K. L., Kupchella, C. E., and Tamburro, C.H., (1977). Urinary Glycosaminoglycan Patterns in Anqiosarcoma of the Liver. Cancer 40:3050-3053.
3. Kupchella, C. E., Jarvis, 0. 0., Curran, K. L. and Tamburro, C. H., (1977). Tissue and urinary glycosaminoglycans (GAG) changes in hepatic fibrosis. Presented at the meeting of the American Association of Study of Liver Disease. Chicago, Illinois, November 1, 1977. Gastroenterology 73(5):1229.
4. Kupchella, C. E., Drake, E., Curran, K. L-, Kennedy, J. and Tamburro, C. H., (1979). Tissue and Urinary Glycosaminoglycans in Transplantable Hepatomas. Gastroenterology 75(5):972.
5. Kupchella, C. E., Seeskas, E., Kennedy, J. S. and Espinosa, E., (1979). Glycosaminoglycan. Changes Associated with Hepatic Tumors: The Contributions of Regeneration and Necrosis. Clinical Research 27(2):389.
003052
55
6. Greenberg, R. A., and Tamburro, C. H. (with C. E. Kupchella et al.), (1978). Early Detection of Disease in Individuals Exposed to Vinyl Chloride. Presented at the 1978 Annual Meeting of the American Public Health Association, San Oiego, CA.
7. Curran, K. L., Kupchella, C. E., Sandoz, J. and Tamburro, C. H., (1979). Urinary Glycosaminoglycan Patterns in Human Hepatic Angiosarcoma, Hepatoma and in Workers at Risk with Angiosarcoma. Gastroenterology 75(5):959.
8. Kupchella, C. E., Drake, E., Curran, K. L., Kennedy, J., and Warick, R., (1981). Tissue and Urinary Glycosaminoglycan Patterns in Three Types of Morris Hepatomas. Cancer Research 4(2):419-424.
9. Tamburro, E. H., Kupchella, C. E., Taylor, K., Landau, E., Green berg, R., Maricq, H., Whelan, J., and Selfter, J., (1981). Screening for the Early Detection of Disease in Individuals Exposed to Vinyl Chloride. Environmental Protection Agency Technical Report 560/6-81-002, U.S. ERA, Washington, D.C.
10. Espinosa, E., Caple, S., Kupchella, C. E., Chla, $., (1979). Two liver antigens undetectable in a fast frowing line of trans planted hepatomas (Morris Hepatoma 7777). Federation of American Societies for Experimental Biology (Houston, Texas). Presented at Dallas, Texas, April 7, 1979; Fed. Proc. 38:1069.
CMA 003053
PROGRAM O'
HISTOLOGIC AND MORPHOMETRIC ANALYSIS: A MEANS OF ACCESSING HISTOLOGICAL HEPATIC INJURY IN CHEMICAL WORKERS; Investigators - G.H. Barrows, R. Schrodt, and C.H. Tamburro
01. Morphometric Assessment of Histological Lesions Characteristic of Vinyl Chloride Injury
D2. Computer-Assisted Morphometric Analysis as a Rapid Means of Determining Collagen Content
D3. Development and Assessment of Morphometric Method of Analysis of Collagen Content from Human Liver Biopsies - Relationship to Age
D4. Light Microscopic Assessment of Various Histological Lesions Found- in Liver Biopsy Tissue Obtained from Vinyl Chloride Workers
Background
Observations made on liver biopsy specimens obtained from vinyl monomer polymerization workers have identified the association of periportal, subcapsular, and mid-zonal fibrosis, and activated sinusoidal lining cells with vinyl chloride exposure. Many have believed these findings to be early indicators of potentially dangerous chemical exposure since these histological findings are characteristic patterns in the terminal or late stages of disease.
The early stages of increased collagen deposition are often difficult to identify due to a lack of data concerning the normal ibllagen content and normal variation of collagen in the sinusoidal spaces. Other types of chemical workers* injuries, such as copper smelters' arsenic-induced Injury, are also associated with increased collagen formation especially in the perisinusoldal areas (1-3, 6-7). In addition, there had been no systematic analysis of the collagen content of the liver's parenchyma based on age. Only subjective data was available regarding "normal1* increases in the quantity of fibrous tissue within the aging liver. Therefore, objective criteria were needed to determine (a) whether the increased collagen deposition in indus trial workers could be used asan indicator of developing cancer, and (b) whether this increased collagen could be identified solely on tissue obtained by liver biopsy.
56
CMA 003054
57
Industrial .vinyl monomer exposure, especially vinyl chloriae, has been associated wiin various hepatic histological annormalities. These nave incluaed nyperplasia of both the hepatocytes and sinusoidal cells. Early histological studies, mainly on autopsy material, have shown focal mixed hyperplasia (hyperplasia of the hepatocytes or sinusoidal cells) to be an early histological alteration associated with vinyl chloride exposure (4,7,8). A double-blind histological assessment was conducted on the liver biopsies of some 120 exposed chemical workers to substantiate this observation and determine its potential use in medical surveillance. Assessment of the degree and duration of the vinyl chloride exposure was determined utilizing rank ordered exposure indices as reported by Greenburg and Tamburro (9).
Objectives
1. Develop a clinically usable method for morphometric analysis of collagen content of liver biopsies.
2. Determine whether computer-assisted morphometric analysis could be used as the standard means of determining collagen content from human 1iver biopsies.
3. Morphometic assessment of normal collagen content and changes associ ated with increasing age.
4. Review and analyze light microscopic findings of liver tissue obtained from vinyl chloride workers to determine whether specific histological lesions were sufficiently characteristic to be identi fied and associated with vinyl chloride exposure.
Research Results
(1) Initially, a manual calculator-assisted approach was used for quanitation of trichrome stainable collagen in liver biopsies. Randomly selected areas of the liver biopsy were photographed. These were projected in an 16 x 16 cm area on a Hewlett-Packard 9864A digitizing plate and area cal culated using a Hewlett-Packard 9815 calculator. Measurements of collagen content and distribution of the perisinusoidal spaces were made from a ran domly selected number of complete grid sections in the various sublobular zones; they were prenumbered from left to right as shown in Figure 1A. The areas were measured in micrographs by superimposing an array of sampling points (Figure IB) and measuring the number of those points which overlaid specific areas. Two randomly selected grid areas from 3 histological, (peri portal, mid-zonal, central) and 4 anatomical locations by 2 methods were studied from 2 to 3 individuals in each bracket.
Portal to central distance was quantitated and divided into 3 sections: pericentral, midzonal, and periportal. A trained observer then manually
CMA 003055
58
outlined all areas staining " as"'<!!frl
the total sinusoidal area
(Figure 2). This was repeated for a total of 3 areas in each biopsy sample. These randomly selected areas provided sufficient sampling to obtain a reproducible estimate of collagen content of various areas of liver lobule and were highly reproducible (Table 1).
HmmI collogon ounntltotlon outHim
Area Percent
2.03 4.30 6.10 14.70
TABLE 1
REPRODUCIBILITY
Digitizer
Inter assay Intra Assay
0. 40
0.19 0.55 1.27
0. 018
0. 052 0.054 0. 6075
Square Counting
0. 27 0. 35 1.10 2. 95
CM* 03056
59
{2} Later aevelcpments for computer quantitation promise to facilitate the execution of morphometric collagen determination. In this approach a video microscopic image is digitized to 4 bit precision, and held in digital video storage (Morphometrix-156 Image Analyzer). This digital image (Figure 3A, 38) contains all density information on a 256 x 512 matrix. The amount of staining of a particular density can be rapidly quantitated by counting the percentage of a particular density which occupies an image. This approach allows rapid quantitation of the total biopsy and enables study of a large number of samples. A second advantage is the adaptability of this technique for 3-dimensional reconstruction and quantitation of liver fibrosis volume. Figure 3 illustrates a computer printout of a histological area and a drawing of the area morphometrically analyzed.
FIGURE 3A: Doiwlty printout of Flguro 1, wit* 10:1 rotation
Urw# in Muor* corrtspoMi to diglut printout XI).
CMA 00305?
E 60
FIGURE 3B 019IUI dmltlM of rotlculln tulnod llvar biopsy.
(3) Histological tissue was obtained for the study of liver collagen
content at various ages from individuals dying of sudden death without historical, clinical or autopsy evidence of hepatobiliary disease, chronic congestive heart failure, excessive alcohol consumption, exposure to hepatoxins or infectious agents known to produce long term hepatic injury,
drug abuse, or prolonged medical use of drugs known to be hepatoxlc or
potentially hepatoxic. The groups were divided into four age brackets: 16-30, 31-45, 46-60, 60 and older. Autopsy tissue was obtained from areas of the liver most frequently obtained in living patients by (A) percutaneous needle, (R, L) open wedge, and (0) transjugular biopsy. Needle and wedge
samples were obtained from 4 areas of the liver as illustrated in Figure 4.
A wedge
needle
SITES Anterior axillary Right lob* left lob Deep pari'vpnoui
/
FIGURE 4
CMA 003058
61
Two hundred and fifty three light micrographs derived from 30 tissue blocks
from 3 normal individuals were studied. A Hewlett Packard S364-A digitizer microcomputer was used to quantitate areas of trichrcme stainable collagen. Collagen estimates varied from .2 to 6.IS (mean 1.25) with considerable variation even in different biopsies from the same patient. Subcapsular biopsies have more collagen than deep biopsies; however, deep biopsies have more variation In collagen content. Collagen content appears to Increase with age and more in midzonal regions than in portal areas (Table 2).
TABLE 2
PERCENT COLLAGEN RATIO IN
THE VARIOUS LOBULE
ZONES
ASS PERICENTRAL PERIPORTAL pericentral
MIDZONAL
MIDZONAL
PERIPORTAL
IS 11.3: 1
3.6: 1
1.4: 1
23 2.8: 1 1: 1 2.4: 1
40 2.3: 1 1: 1 2.3: 1
50 1.3: 1 1: 1 l.S: 1
SI 1: 1
1: 1
1: 1
This increase appears to become detectable in the 4th and 5th decades (Figure 5).
HEPATIC COLLAGEN CONTENT WITH AGE
U<J 3 -
<
.J <
2-
o
figure 5
20
a
* UQ
AGE GROUPS
50
CMA. 30SS
1
62
Differences In central, mid-zonaf anVapJdl*lflPH1fiAW*genl\ vary from 0.49-0.63 percent in the youngest age group and from 4 - 5.35 percent In the older age group. This histological data Is consistent with the ICG clearances In normal adults which show a progressive decrease with age. The decreased functional capacity of normal aging liver may be due to an increased collagen deposition.
(4) Light microscopic assessment of liver tissue obtained from vinyl chloride workers with varying histological lesions was done. In order to substantiate the ability to identify early histological alterations indicative of chemical exposure, 93 liver biopsies from 78 individuals were investigated dupllcatively In a double blind manner. These histological lesions included focal hepatocellular hyperplasia (Figure 6), focal mixed hyperplasia, sinusoidal dilitatlon (Figure 7), focal areas of Increased reticulum (Figure 8), and focal subcapsular fibrosis (Figure 9). The progressive development of vinyl chloride liver lesions are illustrated in Table 3.
Thirty-five of these individuals were exposed chemical workers with hepatic screening test abnormalities, and 13 were exposed workers without hepatic screening test abnormalities who had had liver biopsies for non-liver related medical reasons. A group of 30 individuals who were not chemical workers, who had liver biopsies for nonhepatic-related illness during the sane period of time at the same hospital, were compared. Twenty-three (4836) of the exposed workers had hepatic lesions consistent with exposure, 17 (35%) had only focal hepatocellular hyperplasia, and 6 (13%) had focal mixed hyperplasia or more advanced lesions.
clinical
FINDINGS
TABLE 3
PROBABLE PHASE DEVELOPMENT OF VINYL CHLORIDE PRE-CANCEROUS LESIONS
NONE BWfflENlCAL PORTAL SPLENO- HEPATIC
ABNORMAL HTPER- MEGALY SCAN
TENSION
ABNORMAL
HEPATIJ PEUOSIS
GANGER
HISTOLOGICAL NORMAL FOCAL
PERI- FOCAL
PORTAL AND-
FINDING
HEPATOCTTIC 5MJSOOALMIXED
CAPSULAR
-----------------
HYPERPLASIA FIBROSIS HYPERPLASIA FIBROSIS
SINUSOIDAL CELL DYSPLASIA
ANGIO SARCOMA
CMA 003060
I 4 WM v
LFOCAL HYPERPLASIA OF HEPATOCYTES WITH GREAT VARIATIONS IN THEIR SIZE AS WELL AS THEIR NUCLEI .'WlTHE LATTER ARE FRE QUENTLY DOUBLE, POLYJHROMATOPHILIC OR
VACUOLATED. H&E, ISOx.
FIGURE 8 ^ssnys?sff^: seek!
TION,
HYPERPLASIA OP SINUSOIDAL CELL^7
(CURVED ARROWS) AND HEPATOCYTES
(STRAIGHT AAROHS^Htt, IflOx) nm hyPERPUSIA
FIGURE
j-cru-ti CAPSULAR AND SUBCAPSULAR FIBROSIS."
ANILINE BLUE, 60x.
CMA 003061
64
In contrast only 5 of the comparison group had similar findings. Four (13%) had focal hepatocellular hyperplasia, and 1 (3%) had focal mixed hyperplasia and sinusoidal dilitation. On subsequent biopsy this individual was found to have angiosarcoma and a history of using hair spray containing vinyl chloride as a propellent.
Ten individuals had 28 biopsies reviewed double blindly, and 10 individuals had 23 readings of the same biopsy; 21 of 23 (91%) duplicate readings and 27 of 28 (96%) multiple biopsy readings in the same individuals were identical. Only 18% of the individuals (3 of 17) had either duplicate and/or multiple biopsy readings which disagreed with their prior biopsy assessment. Focal hepatocytic hyperplasia, in addition to the previously described mixed hyperplasia, appeared to be the earliest identifiable change consistent with chemical exposure. These lesions can be consistently identified and are useful in screening chemical workers for evidence of chemical exposure.
Chemical exposure histories to 20 different occupational chemicals were analyzed with regard to the histological findings in the liver biopsy. Portal tract fibrosis, disruption of the limiting plate, and changes in the limiting plate of the portal area had a significant correlation in individuals identi fied as having histological features of chemical liver injury in contrast to those who had nonchemical liver disease. A larger percentage of individuals with histological evidence of chemical injury had higher levels of exposure to vinyl chloride (Figure 10). Changes in the sinusoidal areas also demonstrated the highest correlation with vinyl chloride's cumulative exposure rank months, but not with the cumulative exposure rank months of acrylonitrile, a com parison chemical.
INJURY-EXPOSURE CORRELATION
CLI-CHEMICAL LIVER RUURV ID- LIVCR (M3CA41 SO-STANDARO-NORM
J 60
<
Ot-
AVERAGE VC EXPOSURE
I l34 RATINOS ("II)
/
CLI
FIGURE 10
LD GROUP RATINGS
SO
CMA 003062
03
P.slevance to Industry
These studies demonstrate some highly important and critical information regarding documentation of chemical exposure-induced liver injury:
(1) Rapid methods of quantitatively assessing total collagen content in human liver tissue have been applied. These can provide both retrospective as well as prospective analysis.
(2) Morphometric analysis of collagen can be performed for clinical pur poses from human liver biopsies. This can be automated by using a computer for large volume work.
(3) The identification of increased liver collagen content with age demon strates the need for better standards of "normality" before one can properly determine whether increased liver collagen is a reflection of chronic injury that may be work-related.
(4) There are histologically Identifiable lesions that are consistent with chemical injury; these lesions can be separated from those histological findings of nonchemical liver injury. These characteristic chemical liver injury lesions are correlated with vinyl monomers, most significantly vinyl chloride. Therefore, at the present state of knowledge, one can reasonably determine the presence or absence of significant chemical exposure from the examination of human liver tissue. The present studies have not demonstrated any spontaneous progression in the earliest lesions, i.e., focal hepato cellular hyperplasia when found alone. . The present opinion is that lesion may simply reflect cellular adaptation to chronic exposure while mixed hyperplasia may indicate a higher risk of future cancer development.
References
1. Creech, J.L., Jr. and Johnson, M.N. (1974) Angiosarcoma*of Liver In the Manufacture of Polyvinyl Chloride. J. Occup. Med. 16:150.
2. Falk, J., Creech, J.L., Jr., Heath, C.W., Jr., Johnson, M.N. and Key, M.M. (1974) Hepatic Disease Among Workers at a Vinyl Chloride Polymerization Plant. JAMA 230:59.
3. Makk, L., Creech, J.L., Jr., Whelan, J.G. and Johnson, M.N. (1974) Liver Oamage and Angiosarcoma in Vinyl Chloride Workers. JAMA 230:64.
4. Popper, H. and. Thomas, L.B. (1975) Alterations of Liver and Spleen Amonq Workers Exposed to Vinyl Chloride. Ann. N.Y. Acad. Sci. 246:172-193.
5. Makk, L., Delmore, F., Creech, J.L., Jr., et al_. (1975) Clinical and Morphological Features of Hepatic Angiosarcoma In Vinyl Chloride Workers. Cancer 37:149-163.
CMA 003063
66
6. Creech, J.L., Jr., Makk, L., Whelan, J.6. and Tamburro, C.H. (1974) Hepatotoxicity Among Vinyl Chloride (PVC) Production Workers During First Year of Surveillance Program. Gastro. 64:786.
7. Thomas, L.B. and Popper, H. (1975) Pathology of Angiosarcoma of the Liver among Vinyl Chloride-Polyvinyl Chloride Workers. Ann. N.Y. Acad. Sci. 246:268-277.
8. Gedigk, P., Muller, R., and Bechtelshelmer, H. (1975) Morphology of Liver Damage among Polyvinyl Chloride Worders. A Report of 51 Cases. Ann. N.Y. Acad. Sci. 246:278-285, 1975.
9. Greenberg, R. and Tamburro, C.H. (1981) Exposure Indices for Epidemiological Surveillance of Carcinogenic Agents in an Industrial Chemical Environment. J. Qccup. Med. 23:353-358.
/
CMA 003064
program e
STUDIES OF VINYL MONOMER CHEMICALS AND THEIR METABOLITES USING CHEMICAL STRUCTURE AND SYNTHESIS IN THE DETERMINATION OF TOXICITY OF THESE AGENTS; Investigator - J. L. Wong
El. Synthesis, Purification, and Utilization of Vinyl Chloride Metabolites in Mutagenicity and Carcinogenicity Studies
E2. Detoxification Studies of Vinyl Chloride and Its Metabolites
E3. Vinyl Chloride Metabolite Detection--Chloroacetic Acid
Background
The mutagenicity of vinyl chloride and its potential metabolites was studied in detail by a combination of chemical synthetic and microbiological assay techniques. We prepared and characterized the potential putative metabolites (chlorooxirane and four forms of chloroacetaldehyde), and Dr. Uldis Streips of Microbiology conducted the testing of these compounds in the Bacillus and Salmonella systems.
Since all literature methods for the preparation of chlorooxirane result in mixtures with contaminants such as chlorine, hydrogen chloride, ethylene oxide, polymers, etc., it was necessary to develop a method to prepare pure chlorooxirane.
In order to elucidate the intermediary metabolism of vinyl chloride, i.e., the metabolic activation and inactivation steps, to determine the significant end products of vinyl chloride in body tissues and fluids, the fate of chlorooxirane, the inmediate P450 product of vinyl chloride, was studied using synthetic chlorooxirane to react with non-protein sulfhydryls.
Another prominent reactive property of chlorooxirane is its facile rearrangement to chloroacetaldehyde (CAA). In dimethylformamide at 25*C, it has a half-life of "O.S min in rearranging to CAA. Therefore, the mechanism of deactivation of CAA by cysteine was studied. The plausible cyclic pro duct--3L-carboxy-2,3-dihydro-l,4-thiazine--may be the precursor of the urinary metabolites S-hydroxyethylcysteine and S-carboxymethylcysteine.
67
CMA 003065
68
As a putative metabolite, CAA is well-known to react with adenine and cytosine nucleotides. We will demonstrate that CAA can also react with guanine derivatives at body temperature and physiological pH to yield covalent products. These products will alter the N-H hydrogen-bonding sites in the nucleic acid bonds, hence their formation in a biological host may be consequential in inducing the onset of neoplasia.
Since previous animal studies have not demonstrated chloroacetic acid in the urines of animals at low exposure levels but have been reported in humans at higher exposure levels, we intend to develop analytical methodologies which will help to verify this observation. Such studies may lead to a method of warning of environmental exposure to humans. The first target metabolite for analysis was chloroacetic acid.
Objective
1. To study the chemistry of vinyl chloride toxicity by identifying the intermediates of vinyl chloride metabolism and their reactions with cytoplasmic chemicals.
2. To determine the putative actions of the primary metabolites with regard to:
a) the chemical reactions of metabolites, chlorooxirane (COR) and chloroacetaldehyde (CAA) with sulfhydryls (detoxification).
b) reactions on nucleic acid constituents (mutagenesis and carcinogenesis).
3. To develop analytical methods to detect a target metabolite--chloro acetic acid.
El. Synthesis, Purification, and Utilization of Vinyl Chloride Metabolites in Mutagenicity and Carcinogenicity Studies
The detection study of the putative action of vinyl chloride is based on the hypothesis that such action comes from the modification of the nucleic acid materials by the primary metabolites COR and CAA, Although CAA is long known to react with nucleic acid bases such as cytosine and adenine to form the etheno derivatives, little is known about the reaction of CAA on the most reactive base, guanine. Our study of CAA with guanine base using analytical tools such as HPLC, GC-MS and FT-NMR have shown that the guanosine reaction is enormously complicated.
The hetero-bifunctional alkylating structures of 2-chloroacetaldehyde are shown below.
CMA 003066
o Hi
59
HH
Q -CKf*9-0-C-CH,-Q OH OH
acHf^o-^cHja
HH
a CDrC-o-c-CDi a OD 60'
H
a-CHj^-OCHiCHj och,ch;'
Studies of their reactivities have necessitated:
a. Synthesis of etheno-modified components of RNA and ONA-- angularetheno-guanina, 1 inear-etheno-guanir.a, 1 inear-etheno-guanosine, linear-ethenodeoxy-guanosine, etheno-adenine, atheno-adenosine, etheno-deoxy-adenosine, etheno-cytosine, etheno-cytidlne, and etheno-deoxy-cytidine.
b. Synthesis of acidic hydrolytic products of etheno-modified bases-- 2-aminobiimidazole, 2-formamidobiimdazole, El-O-angular-etheno-guanine, and El-0-1inear-etheno-guanine.
c. Synthesis of alkaline decomposition products of etheno-modified nucleosides--2-amino-biimidazole nucleoside and 2-formamido-biimidazole nucle oside.
d. Synthesis of the deuterated analogues for detailed structural study--8-0-etheno-adenlne, El-O-etheno-cytosine, El-O-angular-etheno-guanine, El-0- etheno-adenine, and El-0-1inear-etheno-guanine.
The kinetics of guanosine with CAA at wide range pH value have been studied with careful pH control. The pK vs. pH plot showed that there are two plateaus, pHl and pH8, and there is minimum at pH 4.5. From the product profiles, two different mechanisms can be suggested (Figure 1).
The putative action of vinyl chloride in respect to the physicochemical properties of the etheno derivatives of cytldine, adenosine, and guanosine Is further studied. The 13C-FTNMR spectroscopic properties are particularly revealing. By means of deuteration and proton undercoupling technique in acquiring the carbon-13 spectra, the various carbon chemical shifts are assigned and the l3C-*H coupling constants determined. From the latter data, the conformational preferences of the sugar moiety in the modified nucleosides are deduced as follows: (1) anti conformation for ethenocytidine
CMA 003067
AiM<ri
CAA
OeQ*y-'f-H*y l
SS''-.*S'*-AmiynmelsU9n4wt6MrplMtiotMy*lftM M*e*yl
70
and (2) syn for etheno-adenosine. Since anti conformation of nucleosides is necessary for the formation and stability of the helix, the influence of the etheno bridge on the adenine nucleus in altering the ribosyl group to syn will impose considerable stress on the ONA chain which might result in biological damages.
E2. Detoxification Studies of Vinyl Chloride and Its Metabolites
A previous attempt by Gothe et al. to trap the putative metabolites COR and CAA in vitro from vinyl chloride with 3,4-dichlorobenzenethiol has led to the idenTTffeation of the product as 3,4-dichlorophenylthioacetaldehyde. It was interpreted to be indicative of the formation of either COR or CAA. We have defined this experiment further. Thus, chlorooxirane in organic medium reacts slowly with 3,4-dichlorobenzenethiol to form 2-(3,4-dichlorophenylth1o) acetaldehyde as 80 percent^of the products. This reaction at room temperature takes about 7 days. At 60*C the reaction is completed in 21 hours giving .the same products. (In both cases some disulfide Cl2Ph-$-S-Ph-Cl2 and other unidentified polymeric materials are observed.) The identity of the product was established by comparison of gas chromatography retention time with an authentic example, by PMR and by mass spectrum. In aqueous acetone (2:1) or aqueous acetonitrile (3:1), the reaction is much faster. As pH > 4, 55 percent conversion is observed in 15 min. which is the lifetime of COR under
CMA 03068
71
zi'ssa ccr.a:::cns, anc ou percent ctr^e-sv:r a; cH = , . .re ipie orccjct
`cariZ'Tiac rrc.t-tries e reactions oy jii5*"' pressure iiquio c> cmatograo-r/ is one alcahyae indicated. On tine other hand, chlcroacetaloe1';'''?!3 if) "1 1 fl '.'35
anotner addition product, which was iaentifiaa oy iviR ana IR ana its facile reversion to the starting materials as 3,4-Cl2?h-S-CH(0H)CH2Cl. In aqueous acetone or aqueous acetonitrile, CAA did not react with the thiol within 1/2 hour, indicating its lower reactivity to the aromatic SH group
compared to COR. These results, combined with the in vitro experiment by Gothe, have confirmed that chlorooxirane is an obligatory intermediate in the metabolism of vinyl chloride.
The detoxification of chlorooxirane was also studied in aoueous media at
different pH's. N-Acetylcysteine was used as a typical cellular sulfydryl
compound involved in detoxification. In aqueous solutions at pH4 and 7, their
reaction was extremely fast at room te^peratur yielding :i-acetyIcystaina-S-
acetaldehyde. It was identified by *H and
NMR and characterized as
the 2,4-dinitrophenylhydrazone derivative. This aidehyae is probably the
precursor of the urinary metabolites, S-2-hydroxyethylcysteine and thiodi-
glycolic acid.
The reaction of chloroacetaldehyde with N-acatylcystaine under controlled pH conditions in aqueous medium at 0*C produced an intermediate compound. Upon warming up the reaction mixture to room temperature, our previously identified thiazene was isolated as the final product. In order to elucidate the stepwise formation of the thiazene, N-acetylcysteine methyl ester was allowed to react with chloroacetaldehyde in chloroform at 0*C. The initial product, plausibly the hemithioacetal HjCO-CO-OMNHCQCHjJCHgS-CHOH-O^Cl,
eliminated HC1 upon neutralization with aqueous sodium hydroxide to produce the corresponding epoxide H3COCOCH(NHCQCH3)CH2S-CHO-CH2. This structural
assignment is supported by Its PMR spectrum. Furthermore, when this epoxide was extracted into chloroform, it rearranged to the S-acetaldehyde H3COCOCH-
(NHCQCH3)CH2-S-CH2CH0, identified by its pmr spectrum and by comparison with
that formed from the reaction of N-acetylcysteine with chlorooxirane.
Even though chlorooxirane and chloroacetaldehyde eventually give the same final product with Jt-acetylcystelne, the rate of reaction and the inter mediates in the two reactions are different. The chlorooxirane conjugates instantaneously with the sulfhydryl compound, while chloroacetaldehyde takes
about 2 1/2 hours for a conparable reaction.
The comparative study of the reaction of chlorooxirane and chloroacetal dehyde with sulfhydryl canpounds can now be summarized In the following reaction pathways with cysteines (unmodified, N-acetyl,^ and N-acetyl-methyl
ester):
CMA 003069
72
X-NH-CH-COOR -------------- ?>
dH2SH
C1-CH2CH0
X-NH-CH-COOR ch2-s-ch2cho
XI
COOR
x-nh-ch-coor ------------- > CH--S-CH-CH,C1 2 6h 2
X=H, Ac R=H, Me
X-NH-CH-COOR CH2S-CH-pH2
Although both routes are converged to yield the cysteine S-acetaldehyde con jugate, their reaction rates are vastly different. In general, chlorooxirane completes its reaction within an hour while chloroacetaldehyde requires over night. These chemical observations can be applied in (1) specific assays for the two putative metabolites in cellular studies of vinyl chloride, and (2) detoxification mechanism of cells exposed to the vinyl carcinogen.
3. Vinyl Chloride Metabolite Detection - Chloroacetic Acid
The methodology includes gas chromatography and mass spectrometry. Gas chromatography results are as follows. Solid supports containing Carbowax and FFAP liquid phases have been used for direct analysis of carboxylic acids. Accordingly, 20 percent FFAP on chromosorb W passes chloroacetic acid at 200* with modest tailing of the peak. However, with this simple column, sensi tivity is limited to concentration ranges of 0.2 - 2 mg/ml H2O (200 - 2,000 ppm). Application of the Improvements reported by Ackman (use of porous poly mer solid support and use of formic acid in helium carrier gas) is expected to improve sensitivity by 100 fold.
Identification of chloroacetic acid by mass spectrometry was carried out. Chloroacetic acid can be identified by mass spectroscopy of water solutions as
dilute as 0.02M (2mg/ml). The 2 doublets of peaks at m/e 49, 51 (^CICH f and 37ciCH2+) and 50,52 (^ClCH3t and ^^ClCH^f) are distinctive because rela tive intensities within each doublet reflect the 76:24 isotopic ratio of 35ci;37ci. Thus, the GC-MS combination technique should be most useful in the detection of the above.
CMA 03070
73
Relevance of Industry Broadly speaking, this is a study for early detection and prevention of industrial cancers. Our chemical methodologies {synthesis, structure, and analysis), aplied as an integral part of the multidisciplinary approach, contribute to elucidate specific molecular events in the effects of vinyl monomers on industrial workers. This information will form a rational basis for safer use of chemicals and design of preventive measures. Our molecular studies also provide the opportunity to develop useful marker(s) in the form of metabolites in the pathogenesis of chemical injury. References Elmore, J. 0., Wong, J, L., Laumbach, A. 0. and Streips, U. N. (1976)
Vinyl chloride mutagenicity via the metabolites chlorooxirane and chloroacetaldehyde monomer hydrate. Biochem. Biophys. Acta, 442, 405. Laumbach, A. 0., Lee, S., Wong, J. L. and Streips, U. N. (1977) Studies on the mutagenicity of vinyl chloride metabolites and related chemicals. Prev. Detect. Cancer (Proc. Int. Symp), 3rd 1, 155. Laumbach, A. D., Streips, U. N. and Wong, J. L. (1978) Chloroacetaldehyde-induced damaqe to Bacillus subtil is. Abs. Ann. Mtg. ASM. p. 125.---------------------------- --------------------------- a--------Laumbach, A. D., Streips, U. N. and Wong, J. L. (1979) Chloroacetal dehyde- induced damage to Bacillus subtil is, Abs. Twelfth Internat. Congress Microbiol. Joseph, J. T. and Wong, J. L. (1982) Model study of vinyl chloride metabolism sulfate reactions with chlorooxirane, Carcinoqenesis (in preparation).
CMA 003071
PROGRAM F
ASSESSMENT OF ASSAYS FOR THE CARCINOGENIC POTENTIAL OF INDUSTRIAL CHEMICALS USING PROKARYTOIC AND EUKARYOTIC SYSTEMS. Investigators; U.N. Streips and G. Sonnenfeld
FI. Bacterial Assays for Testing Carcinogenicity and Mutagenicity of Indus trial Chemicals.
Background
Our laboratory had instituted Salmonella reversion. Bacillus subtil is repair, and Bacillus subtil is forwa"rd mutations assays for screening the mutagenic potential of chemicals (1-3). For that reason we became an integral part, first, for B. F. Goodrich, then for the Manufacturing Chemists Association sponsored projects on industrial chemical risk assessment.
Objective
1. To screen a series of industrial and environmental - health-related chemicals for mutagenic potential.
2. To initiate with Dr. G. Sonnenfeld a rapid mammalian assay to better predict human-related bacterial chemical activity and carcinogenic potential.
Research Results
In our previous progress reports we have documented the work which delineated the involvement of chloroacetaldehyde and chlorooxirane as the probable active components of vinyl chloride-mediated carcinogenesis. In addition, we screened a multitude of other chemicals generated by Dr. John Wong (our collaborator in this study) or by other investigators in the university or industry (1-3). This is documented in Table 1. Recently, in collaboration with Dr. Gerald Sonnenfeld, a new, exciting, potential screen for carcinogens was developed (4,5). This involved the inhibition of inter feron induction and was specific for several carcinogens (including chloro acetaldehyde) but not for non-carcinogenic analogues (including some muta gens). It should be illustrative of some of the molecular mechanisms of carcinogenesis attack on susceptible cells. We continue to develop this system even though our support from CMA has ended (6-8).
74
0030
A screening laocratory (using microoiai assays.' -':r '"stirutic-'il e -- 3 purooses is being maintained. We nave oropcsad to the state of Kentucky that a regional chemical testing laboratory be funded to se-vs the industry end university needs in this part of the Commonwealth. That proposal is still pending.
TABLE 1
w<ut of rom*rrr svutmkis torso re* "OTKEticirr
1. Keti`efclarttfcisrL*cycl*fciic4tceraiiyi p*fxl4e
S.13W.IU *
2. lenaoyl permxUe
si
3. S'*ea?e*^-,i-e''*ny;aeacamtie t. J cyel--mci--irbagylomy-M-ehanyUceCMnde 5. bifl^yclebucaM cArbeeyl paraxiXe 4. Ailateila 7, ChlonMcXeaxl 1. )u#ft)py**A
>* MX MX *4* *x **
4. --
10* <3il9*MXCftl4mliyXm
a**
u. 4tOlUt*f4cla
11* ounotii*
a**
13* nun U. ityrwm at* 13* ),* .Hit* Mw
aa a
u. fcU<*ta-eMaracft?L)***yl pAethce
Xt
17, lets cbUraechTl pneemec# (Ms cyelaheeyUsiae talc) u. Uf uflnca (tee mken uk emtar 19. ! MOsiM fne MaMvt vttlMt cancer
MX a * *
* * rated**
* - --nmeete
w * mneilt umiU
- * haMMtUB HIPUW
-- - Hnailr wwli
lulcUls XX MX VR MX MX a* Xt a aa aa a aa a a MX MX XX xt XX
To further elucidate molecular mechanisms of carcinogenesis, in collaboration with John Hong, we inltltated a study of DNA-interaction with carcinogens, and with Ron Doyle, control of cell division processes in bacteria. Progress In this area has allowed us to secure a grant from the National Science Foundation to carry on with the work. Soon, we will be able to describe the cellular controls which maintain proper cell division In
bacteria, then relate these findings to mamnalian cells. At that time, we will be able to examine carcinogen attack on these processes and determine which events lead to loss of cell division control and neoplastic growth.
CMA 003073
76
Support from the CMA has been instrumental in generating and maintaining research activity in our laboratory relating to carcinogenesis and cell cycle events. We deeply appreciate this support.
Relevance to Industry
With the tremendous number of chemical formulations generated yearly, a battery of rapid screens are crucial for examining the environmental and health-related impact of these chemicals. A regional laboratory can do such screening effectively and economically as shown by the results previously described. In addition we have demonstrated that such research also leads to innovation in terms of new assays (the interferon assay), and related research (the studies on cell division). Industrial support also has led to other granting. Valuable mutagenesis information has been provided to industry regarding crucial chemicals. In turn, industry has provided us with the opportunity to expand and solidify our research efforts. The interaction has been optimal.
F2. Preliminary Studies on the Use of Inhibition of Interferon Induction as an Indicator of Mutagenicity and Carcinogenicity of Chemicals
Background
Interferon, which was originally described as an antiviral agent, has since been shown to have several other activities, including an antitumor activity (9). Clinical trials are now in progress to determine the efficacy of interferon as an anti-cancer agent (10).
We became interested in the interactions of carcinogens, or cancercausing substances, and interferon. Early studies by DeMaeyer and others suggested that there was indeed an interaction between carcinogens and interferon induction (11-13). Pretreatment of rat embryo fibroblasts with the carcinogens triethylenearoine, 4-nitroquinoline-N-oxlde, benzo-(a)-pyrene, and 3-methylcholanthrene all inhibited the induction of alpha-beta Interferon by viruses, without affecting the gross viability of the cultures or the replication of the viruses (11-13). Several poorly or noncarcinogenic analogs, such as benzo-(e)-pyrene, had no effect on the production of interferon (11-13). The effect was observed after only one day of incubation of very small amounts of carcinogen with the tissue cultures. In addition, Hahon and co- workers have shown that incubation of cell cultures with various forms of aflatoxin also inhibited the induction of interferon in the cultures (14). in this case, the degree of inhibition correlated with the in vivo carcinogenic potential of the aflatoxin form (14). Asbestos fibers a"H3 coal dust have also been reported to inhibit interferon induction In tissue culture (15,16). In vivo, injection of methylcholanthrene into mice inhibited the induction of alpha-beta interferon (17). These results created an interest in our laboratory to further study this phenomenon.
CMA 003074
77
i
1 . ~0 ***0??t
Sir*" ?
C ~.0
inhibized incarferon induction.
: " a - - rs-^o^isn "',`,?trS2tniC,'t
2. To begin studies to determine if effects on interferon induction could be used as a reliable indicator of carcinogenic potential of chemicals.
3. To study the mechanisms of the observed effects.
Research Results
Our first step was to establish the system in a mouse culture model,
since this was mors appropriate to current interferon tecnnology. Mouse embryo tissue cultures were prepared, treated with carcinogen or analogue for 24 hr., washed with fetal bovine serum-containing medium and with serum-free
medium to help remove carcinogen, challenged with an interferon inducer (either Newcastle disease virus or poly I:C), and then assayed for antiviral activity. Earlier data was able to be duplicated and those findings extended. Several known carcinogens including 7,12-dimethy1benz-(a)-anthra cene, benzo-(a)-pyrene, 2-aminofluroene, aflatoxin-3] and the #4 fraction of tobacco smoke condensate all inhibited interferon induction (5). Styrene
oxide, an important industrial chemical which was positive in the Ames Salmo nella assay but negative in all Bacillus assays done to date (11), also inhibited interferon induction. Ethyl methanesulfonate (EMS) and methyl
methanesulfonate, differ with respect to their carcinogenic potential as determined by tumor induction (18,19). MMS is a mutagen and highly carcino genic, while EMS is a potent mutagen but rarely carcinogenic. In our assay, MMS strongly inhibited alpha/beta interferon induction, while EMS had no effect. Additional studies In our laboratory extended these findings to the potent carcinogen chloroacetaldehyde and Its noncarcinogenic analogues chloroethanol and chloroacetic acid (4). Only chloroacetaldehyde Inhibited inter
feron induction.
An additional finding of interest was the apparent requirement for
activation of carcinogens before they could inhibit Interferon induction. In
a preliminary study, we were able to show that addition of reduced glutathione
to our cultures blocked the inhibition of interferon Induction by benzo-(a)-
pyrene (4). Reduced glutathione can block the active metabolites of
carcinogens (20), which suggested that these active metabolites were required
for the effects of benzo-(a)-pyrene on interferon induction.
/
Relevance to Industry
We believe these studies to be highly relevant to the chemical Industry because: 1) the studies yielded Information on the effects of toxic chemicals on the interferon system, an important body defense against cancer, and 2) the studies may eventually lead to a new assay system for discriminating between carcinogenic and noncarcinogenic chemicals.
307s
78
References
1. Horowitz, S., Doyle, R.J., and U.N. Streips. (1978) Restricted
chromosome-membrane association in a stable L-form of Bacillus subti1 is. In Transformation-1978. Proceedings of the fourth European Meeting on Bacterial Transformation and Transfection, pp. 245-251.
2. Horowitz, S., Doyle, R.J., Young, F.E., and U.N. Streips. (1979)
Selective association of the chromosome with membrane in a stable L-form of Bacillus subti1 is. J. 8acteriol. 138:915-922.
3. Streips, U.N., Horowitz, S., and R.J. Doyle. (1980) Genetic
analysis of DNA-surface interactions in Bacillus subti1is. Microbiology 1980, ASM Press, pp. 284-287.
In
4. Sonnenfeld, G., Barnes, M.C., Schooler, J., and U.N. Streips. (1980) Inhibition of interferon induction as a secreen for the carcino genic potential of chemicals. In Interferon: Properties and Clinical Uses. Leland-Fikes Foundation Press, Dallas, pp. 589.
5. Barnes, M.D., Streips, U.N., and G. Sonnenfeld. (1981) Effect of
carcinogens and analogs on interferon induction. Oncology,
38:98-101.
----------
6. Streips, U.N., Laumbach, A.D., and R.E. Yasbin. (1981) Bacterial
mutation monitors for active metabolites of clinical carcinogens: Bacillus subti1 is assays for mutation and repair In Microbial Testers forthemical Carcinogenesis, I.C. Felkner, "id., Marcel Dekker, New York, pp. 131-145.
7. Tamburro, C.H., Wong, J.L., and U.N. Streips. (1982) Approaches to
occupational cancers. In Clinical Medicine for the Occupational Physician, Alderman, antFHanley (eds.), Marcel Dekker, New York, pp. 255-295.
8. Clarke, J.S., Streips, U.N., Hoffman, J.L., Fok, F.F., and J.A.
Yankeelove. (1980) J. Toxicology and Environmental Health (submitted).
9. Gresser, I. Cell. Iwnunol., (1977) Commentary on the varied biologic effects of interferon 34:406-416.
10. Merigan, T.C. (1982) Interferon Therapy in Human Viral Infections and Malignant Disease, pp. 88-90, In, Stiehm, E.R. Moderator, Ann. Intern. Med. 96:80-93.
CMA 003076
79
11 DaMaeyer, ., ar.d Dsr'aa: er-Gu-
J-iT.ciny iCuG 1 af!wTirST.^ v* `i<' r"croii ro'T;dciCTi in rdc
rvo cstis
infected with Sindbis virus J. Natl. Cancer Inst. 32:1317.
.12 DeMaeyer-Guignard, J., and DeMaeyer, E. (1965) Effects of carcinogenic and noncarcinogenic hydrocarbons on interferon synthesis and virus plaque development. J. Natl. Cancer Inst.
34:264.
13. DeMaeyer-Guignard, J., and DeMaeyer, E. (1967) Inhibition of
interferon synthesis by triethylenemelamine and 4-nitroquinoline-N-oxide. Arch. Gesamte Virusforch. 22:61-68.
14. Hahon, N., et al. (1979) Aflatoxin inhibition of viral interferon induction. Antlmicrcb. Agents Chamother. 16:277-282.
15. Hahon, N. (1974) Depression of viral interferon induction in cell monolayers by coal dust. Br. J. Indus. Med. 31:201-208.
16. Hahon, N., and Eckert, H.L. (1976) Depression of viral interferon induction in cell monolayers by asbestos. Environ. Res. 52-65.
17. Waker, A., Feller, H., and Gericke, Da Hemmung. (1971) Der inter feron-induction durch 20-methylcholanthrene jn^ vivo. Naturwissenschaften 58:274-275.
18. Roe, F.L.C., et al. (1963) Tests for carcinogenesis using newborn mice: 1,2-benzanthracene, 2-napthylamine, 2-naphthyl hydroxyl amine and ethyl methanesulfonate. Br. J. Cancer 17:255-260.
19. Casto, B.C., et. al. (1977) Development of a focus assay for trans formation of hamster cells _i vitro by chemical carcinogens. Cancer Res. 37^:3508-3515.
20. Chasseaud, L.F. (1979) Glutathione (reduced) and glutathione-Stransferase block the carcinogenic event by trapping the ultimate metabolites. Adv. Cancer Res. 29:176-255.
CM& 003077
PROGRAM G
THE STUDY OF TISSUE ANTIGENS AND ANTIBODIES IN THE DETECTION OF VINYL CHLORIDE INJURY; Enrique Espinosa, M.D.
Gl. The Study of Tissue Antigens from Liver Tumors, Angiosarcoma, and Hepatomas.
G2. Circulating Antigens and Autoantibodies in Vinyl Chloride-Associated Liver Disease
Background
In hepatic fibrosis and angiosarcoma associated with vinyl chloride exposure of industrial workers, manifestations of the disease could not be detected in most cases until the process was far advanced (1). Normal values of liver function tests were reported in a case with significant vfnyl chloride hepatic fibrosis (2), and only a small percentage of workers of a plant unit where 7 cases of liver angiosarcoma were diagnosed had abnormal blood screening tests (3). Thus, conventional liver function tests do not appear to be sensitive indicators of vinyl chloride liver disease. Develop ment of more sensitive and specific methods for detecting the disease in early stages would be of great importance. An approach to this may be provided by antigenic studies in view of the tissue antigenic modifications which are known to occur in neoplasia. For example, in human carcinoma, loss of antigens have been reported in squamous cell carcinoma (4,5) and in ovarian carcinoma (6,7), loss of the ABH blood group isoantigens in some solid tumors (8,9), and of HL-A isoantigen in lymphoma (10). Also, tumor-specific trans plantation antigens have been demonstrated in a number of experimentally induced tumors (11-14) as well as tumor-associated antigen in spontaneous tumors in man (e.g. 15-18). In such an antigenic study of liver angiosarcoma the question arises whether the fibrotic and angiosarcomatous livers contain antigens that are quantitatively or qualitatively different from those present in normal tissue and whether such changes could stimulate an immunologic response. If such hypothetical changes are demonstrable and proved to be specific, they may be of use in diagnosis of vinyl chloride related liver disease.
Objective
1. To test for liver antigenic changes in a) angiosarcomatous liver tissue, b) chemically-induced hepatomas, and c) cultured human liver carcinoma cells.
80 CMA 003078
81
2. To test for abnormal serum antigens and autoantibodies in patients with histories of vinyl chloride exposure including individuals with liver angiosarcoma, liver dysfunction with fibrosis, and with normal liver function tests. Antigens studied included liver specific antigen (LSA) (19), and F-antigen (20,21), tissue antigens of wide organ distribution (22,23), and bile antigens (24). Autoantibodies were to nuclei, mitochondria and smooth muscle. Patients' sera were also tested by immunofluorescence for possible reactivity with rats exposed to vinyl chloride (25).
Research Results
1. Liver antigenic changes
a) angiosarcomatous liver tissue
Liver angiosarcomatous tissue was analyzed in this work for presence of neoantigens, normal tissue antigens and tumor bound immunoglobulins. Several normal tissue antigens were found by immunodiffusion to be present In the tumor. These included the previously described liver-specific antigen, (LSA) (19) and antigens which are shared with several tissues (22,23). In addition, a tumor associated protein antigen and a glycoprotein liver antigen found, to be absent in angiosarcoma were identified and characterized (25).
Tissue distribution of liver angiosarcoma related antigen is shown in Table 1. Preparations containing tumor associated antigen were found to inhibit lymphocyte transformation tests In vinyl chloride workers suggesting that these workers have a decreased lymphocyte response to these preparations (26). Further, antigen coagulation Factor VIII was detected in the angio sarcoma cells, pointing to an endothelial cell origin of the tumor (25). Finally, immunoglobulin G bound to the angiosarcomatous tissue was demon strated by Inanunofluorescence and elution experiments suggesting antibody stimulation by the tumor (25).
TABLE 1
TIJSUI DISTfttVUTtOM or LI* in
AHGlOSAftCOMA-miATID ANTfOf N
TtSSUt VXTRACT
A MOIOtAftCOMA- ft VLATfD AHTtOIN*
Liver Kldatf Sptau Luftf
V
Aa(la|l*arini Mfarn me* afc**rfc4 with tyepfclH*4
tract*, (04 aif/iml, aaA tvetatf agctact
rccima aatract.
*Praaaaca vl
IMIttltd *y .
CMA 003079
=n t t ~sn missm:
e1 ace: liver arci" ar-cc'-a
3":"uiazaa rurcr.sr sc-cias of antigenic calaticn in chemically-inaucea
nepatomas and in cultured human liver carcinoma cells.
In studies performed with the fast growing and undifferentiated chemically-induced ,Mcrris haoatcma 7777, 2 liver antigens were found to be
absent. These antigens were characterized and partially Isolated. In studies of their occurrence in other tissues, one of these antigens (Antigen I) was shown to be present in kidney and spleen in addition to liver. The second antigen (Antigen II) was detected only in liver. Antigen II was found unrelated to liver-specific F-antigen, differing in a number of properties and in immunologic reactivity.
In studies of their suoceiiular distribution in normal liver, Antigen I appeared localicad in c>tosoi {5**) and mitochondrial (38%) fractions. Antigen II was about eaually distributed in cytosol, mitochondria and nuclei fractions with little amounts in microsomes. Antigen I has a electrophoretic mobility in immunoelectroohoresis close to that of serum gamna-globulins and Antigen II to that of serum alpha-globulins. The two antigens were completely inactivated with Pronase indicating that both antigens are proteins or protein associated. Both antigens were relatively thermolabile; they were partially inactivated following incubation at 56*0 and completely inactivated at higher temperatures. Both antigens were completely inactivated when incubated in pH buffer lower than 3.5. In Sephadex-G200 gel filtration. Antigen I behave<^^k
like a protein of approximately 51,000 Daltons, using as standards serum^^
albumin, ovalbumin, chymotrypsinogen and ribonuclease. The molecular size of Antigen II (determined on a Bio-gel A5m column) was approximately 240,000 Oaltons, using aldolase, catalase and ferritin as markers.
The two antigens were found In the more differentiated and slower growing hepatomas 5123tc and 9618A at about the same concentration as normal liver. The fact that hepatoma 7777 is the fastest growing and least differentiated of the tumors studied suggests a possible functional relationship between the absent antigens and these properties (28). These antigenic deletions may be used as indicators in the early detection of liver tumors and in the evaluation of the rate of growth, histologic differentiation and metastatic
properties of such hepatomas.
Another liver constituent which may serve as a sensitive Indicator of chemically-induced liver tumors, liver-specific F-antigen, was studied. In studies on the behavior of this antigen in Morris hepatomas, it was found that different types of these chemically-induced tumors have quite different levels of F-antigen.
F-antigen appeared to be absent in the fast growing hepatoma 7777. In the slow growing hepatoma 9618A, the concentration was very low ranging from less than 2% to 10X of the normal liver concentration. The medium growing
hepatoma, 5123tc, highly metastatic, had about twice the concentration as
CMA 003080
83
normal liver. F-antigen of hepatoma 5123tc "anXi6f"1rt>i,iiWrfTialiver were found localized in- the cytosol subcellular fraction and were determined to be
immunologically identical and to have equivalent electrophoretic mobility and molecular weight (29).
Since the antigen was undetectable in the fast growing hepatoma and undetectable or very low in the slow hepatoma, the level of F-antigen does not appear to correlate with the rate of growth of these tumors. A possible relationship between metastatic properties and F-antigen is now being considered because the hepatoma with the increased concentration of F-antigen was by far the most highly metastatic. This may prove useful in treatment of tumors.
c) cultured human hepatoma cells
In studies on cultured human liver carcinoma cells (after establishing
optimal conditions required for the maintenance in serum free media of
PLC/PRF/5 human liver carcinoma cells) it was determined that these hepatoma
cells, similar to the experimental Morris hepatoma 7777, are deficient in
liver-specific F-antigen. Nevertheless, these cells, like normal liver cells,
produce serum albumin, fibrinogen, transferrin, alpha-1 antitrypsin and
alpha-2 macroglobulin as shown by
immunodiffusion (30,31) ,and
immunofluorescence (32). These data add further support to the clinical
observation that tissue antigens are more useful for treatment and follow-up
care than screening and early detection, and that antigenic deletions may
prove useful in early screening.
2. Abnormal Serum Antigens and Autoantibodies
Serum autoantibodies to nuclei,mitochondria and smooth muscle were negative in all patients examined. In addition, serum from these patients did not show reactivity with liver fromrats exposed to vinyl chloride.
Liver-specific antigen ISA (19), bile antigens (24) and other tissue antigens (22, 23) associated with liver damage were not detected in these patients (25).
Relevance to Industry
These studies are relevant to chemical industry in view of the evidence provided showing Important changes in the levels of angiosarcomatous liverantigenic components in association with vinyl chloride exposure. Deletion of liver antigens were also demonstrated in chemically-Induced hepatoma. In addition, these observations may eventually prove useful in the development of new approaches for screening of chemical-associated tumors.
References
1. Heath, C.W., Or., Falk, H., and Creech, U.L. (1975) Characteristics of cases of angiosarcoma of the liver among vinyl chloride workers in the United States. Ann. N.Y. Sci., 246:231.
CtAA 003081
w3,*1t
'I '
jHi ) J * i t f # - ! - - *
v. * ij i .* * * v i' i j -- i *- i l* c 3 j i' v't r
exposure. Ar.n. d.Y. Acad. Sci., 2
J * *J*
} - =**?;
?f
er cassation of
3. Wyatt, R.H., Kotchen, J.M., Hochstrasser, D.L., Buchanan, J.W., Jr., Campbell, D.R., Slaughter, J.C., and Doll, A.H. (1975) An epidemiologic study of blood screening tests and illness histories among chemical workers involved in the manufacture of polyvinyl chloride. Ann. N.Y, Acad. Sci., 246:80.
4. Nairn, R.C., Richmond, H.G., McEntegart, M.G., and Fothergill, J.E. (1960) Immunological difference between normal and malignant cells. Br. Med. J., 2.: 1355.
ruthars, C., and Baumler, A. (1955) Immunochemical staining with fluorescein-labeled antibodies as an aid in the study of skin cancer formation. J. Natl. Cancer Inst., 34:191.
6. Burton, R.M., Hope, N.J., Beyerle, M.P. and Espinosa, E. (1977) Tissue antigens in ovarian carcinoma. Oncology 34:146.
7. 3urton, R.M., Hope, N.J., Beyerle, M.P. and Espinosa, E. (1978) Gewegsanti gene bein ovarialkarzlnom. Onkologle 1:75.
8. Kay, H.E.M. (1957) A and B antigens in normal and malignant cells, Br. J. Cancer, 21:409.
9. Davidson, I., and Ni, L.Y. (1969) Loss of isoantigens A, B and H in carcinoma of the lung. Am. J. Pathol., 57:307.
10. Seigler, H.F., Kremer, W.B., Metzgar, R.S., Ward, F.E., Haung, A.T., and Amos, 0.8. (1971) HL-A antigenic loss in malignant trans formation. J. Natl. Cancer Inst., 46:577.
11. Cryan, W.S., Hide, R.M., and Garb, S. (1966) Demonstration by gel diffusion of antigen in spontaneous mouse tumors. Cancer Res., 26:145, .
12. Heppner, G.H., and Pierce, G. (1969) In vitro demonstration of tumor-specific antigens in spontaneous mammary tumors in mice. Internat. J. Cancer, .4:212.
13. Isojima, S., Yagl, Y., and Pressman, D. (1969) Antigens common to rat hepatoma induced with 2-acetyl aminofluorene. Cancer Res., 29:140.
14. Kahan, B.D., Holmes, E.C., Reisfeld, R.A., and Morton, D.L. (1969) Water soluble guinea pig transplantation antigen from carcinogeninduced sarcomas. J. Immunol., 102:28.
CMA 003082
85
15. Hughes, L.E., and Litton, B. (1964) Antigenic properties of human
tumors: Delayed cutaneous hypersensitivity reactions. 8r. Med.
J. 2:209.
------------
16. Itakura, K. (1963) Studies on human cancer antigens by gel diffusion methods. Gann, 54:93.
17. McKenna, J.M., Sanderson, R.P., and Blakemore, W.S. (1962) Extrac
tion of distinct antigens from neoplastic tissue. Science,
235:370.
-----------
18. Burton, R.M., McGrew, T.L., Barrow, G.H., Beyerle, M.P., Fort-
wengler, P.H., Day, T.G., Kuhns, S.H., and Espinosa, E. (1979) Occurence of a thermostable antigen of ovarian carcinoma in normal tissues and secretions. Cancer, 43:2385.
19. Espinosa, E. (1973) Circulating tissue antigens. II. Studies on an organ-sepcific antigen of human liver. Lab. Invest., 29:556.
20. Espinsoa, E. (1977) F-antigen in liver injury. Gastroenterology,
72:985.
----------------------
21. Espinosa, E. and Caple S. (1981) Extrahepatic immunofluorescent
reactivity of antisera detecting liver F antigen. Fed. Proc.,
40:764.
----- ------
22. Espinsoa, E. (1974) Circulating tissue antigens. I. Tissue antigens in serum of patients with diseases involving injury of the liver and of other organs. Clin. Exp. Imnunol., 16:153.
23. Espinosa, E. (1976) On two tissue antigens detected in pathologic sera. Lab. Invest., 34:8.
24. Espinosa, E. (1976) Circulating tissue antigens. III. Identifica
tion and characterization of antigens of limited and of wide body distribution in human gallbladder bile. Presence of serum of
patients with acute hepatitis. Clin. Exp. Immunol., 25:410.
25. Espinosa, E. (1976) Imnunopathologic observations in liver angio
sarcoma. Jji Nieburgs, H.E. (ed.). Third international symposium on detection and prevention of cancer proceedings, New York, Marcel Dekker, Inc.
26. Fortwengler, H.P., Dever, M.E., Tamburro, C.H. and Espinosa, .
(1978) Lymphocyte transformation tests in vinyl chloride (VC) workers. Fed. Proc., 17:362.
27. Fortwengler, H.P., Jr., Jones, D., Espinosa, E. and Tamburro, C.H.
(1981) Evidence for endothelial cell origin of vinyl chloride induced hepatic angiosarcoma. Gastroenterology, 80:1415.
CMA 003083
86 28. Espinosa, E., Caple, S., Kuchella, C. and Chia, S. (1979) Two liver
antigens undetectable in a fast growing line of transplanted hepatoma (Morris Hepatoma 7777). Fed. Proc., 38:1069. 29. Espinosa, E., Chia, $., Caple, S. and Kupchella, C. (1979) Liverspecific antigen in transplantable hepatomas having different growth rates. Fed. Proc., 38, 1069. 30. Johnston, P.8., Espinosa, E., Chia, S. and Caple S. (1979) Proper ties of 14 week matintenance cultures of PLC/PRF/5 cells. In vitro, J5_:227. 31. Espinosa, E., Johnston, P.B., El-Naggar, M.M. and Caple, S. (1980) Serum and liver antigens in cell sheets and culture fluid of PLC/PRF/5 human hepatoma cells. Lab. Invest., 42:18. 32. Espinosa, E., Johnston, P.B., and Caple, S. (1980) Immunofluorescent localization of plasma proteins in cultured human hepatoma cells. Fed. Proc., 39:777.
CMA 003084
PROGRAM H
THE USE OF ISOLATED MAMMALIAN LIVER CELLS FOR THE STUDY OF CHEMICAL MONOMER METABOLISM; Investigator, R. C. Feldhoff
HI. Isolation of Manmallan Liver Cells for the Study of the Metabolism of Chemical Monomers
H2. The In Vitro Study of Albumin Synthesis by Liver from Human Biopsies
Background
Presently there is no simple or even complex method to assess the functional capability of the human liver to handle exposure to various chemicals and/or their metabolites. In general, the rat has proven to be the most useful experimental animal for studying hepatic metabolism. Perfused liver slices and isolated hepatocyte systems have been developed to better study the interrelationship and to control the myriad processes of liver metabolism. In the perfused liver the architecture of the organ is preserved but separated from-other body influences. Newer in situ techniques allow the liver tissue to never be without a supply of oxygenated- red cells. The same technique can also be used to prepare isolated liver cells enzymatically.
The intact liver consists of at least four cell types, whereas isolated liver cells are nearly homogeneous in population. These cell suspensions provide technical advantages in that a number of conditions can be tested at one time and many uniform serial samples can be collected. Preliminary investigations were therefore done to determine whether the human liver biopsy material can function In a manner equivalent to liver slices and whether these tissues would demonstrate similar findings to those^of isolated cell suspensions. If this technique were made functionally feasible it could then be used to study the metabolism of xenobiotlcs using viable human liver tissue in an vitro manner.
Objective
1. To determine if an in vitro adaptation could be developed which would utilize animal/human biopsy material for assessing the functional capability of human liver cells. Protein metabolism has been used as the standard indicator and criteria for comparison
87
CMA 003085
.2 To determine the usefulness of this technique in human bioosy
-atsria] cbtained fjr rcucine p=c:cai purposes via perpucs; ecus sno
h 4 ^4lGU J
Research Results
Our first step was to verify the clinical and biochemical conditions needed for handling human liver biopsy material obtained during routine medi cal procedures. Appropriate assay conditions are being determined to assess the functional capability of the liver at the time of the biopsy to synthesize retained and secreted protein. At the same time, the biopsy's histopathology will be assessed and correlated with the biochemical data. The technique used to study both protein synthesis and secretion is shown in Figure 1. The his topathology is illustrated in Figure 2.
IN VTTRQ TTCHN!1L'E
FOR STUDY OF HUMAN LIVER TISSUE
a - retained protein 3 - SECRETORY PROTEIN C LIGHT MICROSCOPY
LIVER BIOPSY
FIGURE 1
Mrr af
DIVIDED LIVER BIOPSY
ofi
--~* f*mmw
r pihm
Ifiumacmnrw*. *##*
ri- *
CMA 003086
1
39 The initial experimental studies utilizing liver perfusion and the isola tion of hepatocytes techniques provided the hepatocytic and nonparenchymal cells for Du and Tamburro's study of the oxidizing and detoxifying capabili ties of these cells. Subsequent experiments have been used to quantitate the intracellular albumin synthesis, the rate of albumin secretion by the use of specific antibody fractions available for human and rat albumin. Initial results are illustrated in the rocket immunoelectrophoresls patterns from rat liver biopsy study (Figure 3) and the amino acid analysis is seen in Figure 4. The technique for liver cell identification after cell separation by the perfusion technique is illustrated in Figure 5.
CMA 003087
!I A*
I I!
''V
7
r,9 4**0+***I .I
> 4* "
: .v*- hl ;:; ; . -. . , '
!., TV'*:-- y
':
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; INi vIutU i .i-i ;:.!i i
90
FIGURE 4
ML*
'll i I
VllllUcffinilMi. -'i'is'v '1 ' ' ^
TECHNIQUE FOR HEPATIC CEIL TYPE IDENTIFICATION
MARKER
CELL TYRE
dna/rma ALL CELLS
XC
EC
FB
Although this study was a last year addition to our Initial proposal, it has provided the preliminary exploration into the adaptation of highly sophisticated laboratory techniques to human tissue in an in vitro system. While the work of these studies is still developmental, it provides promise for future clinical use. Such use could include determination of an indi vidual liver's ability to oxidize and detoxify xenobiotics. The degree and nature of liver cellular injury or impairment could be determined in a quantitative biochemical fashion, and could be directly correlated with
CMA 003088
91
morphological findings. These techniques could be also used to determine the
degree of biochemical adaptations of the human tissue in individuals who have
been exposed to xenobiotics. Finally, these methods could, on sequential biopsy, provide clinical information regarding whether these alterations persist or revert bade to a normal state.
Although this is a very futuristic attempt to adapt presently developed methodology, it does accurately reflect the direction in which clinical research should be directed in order to better assess the human capability of sustaining environmental changes.
References
1. Ou, J. and Tamburro, C.H. (1980) Oxidative and detoxifying ability of
liver mesenchymal vs. parenchymal cells in the metabolism of xenobiotics. Gastroenterology 79, 1013.
2. Exton, J.H. (1975) The perfusion rat liver. Methods in Enzvmoloqv
37, 25-37.
---------------------- --------
3. Feldhoff, R.C., Taylor, J.M., and Jefferson, L.S. (1977) Synthesis and secretion of albumin in vivo, in perfused liver and isolated hepatocytes: Effects of- hypophysectomy and growth hormone treatment. J. Biol. Chem. 252, 3611-16.
4. Feldhoff, R.C., Taylor, J.M., and Jefferson, L.S. (1977) Albumin
synthesis by isolated rat hepatocytes. Effects of amino acids, bovine albumin, rat serum and hormones. Fed. Eur. Bloch. Soc. (Abstract).
5. Ledden, D.J., Feldhoff, R.C. and Gray, R.O. (1980) Purification and
characterization of human albumin fragments. Fed. Proc. 39, 1676 (Abstract).
6. Leevy, C.M. (1963) In vitro studies of hepatic DNA synthesis in percutaneous liver biopsy specimens from man. J. Lab. Clin. Med. 61, 761-766.
7. Peters, T., Jr. (1975) Serum albumin. In The Plasma Proteins, 2nd ed., Putnam, F.W. ed., Vol. I, pp.^33-181, Academic Press, NY.
8. Peters, T., Jr. (1980) Albumin: An overview and bibliography. Miles Laboratories, Inc., Elkhart, IN.
9. Whelan, J.F., Jr., Creech, J., Jr. and Tamburro, C.H. (1981) The adequacy$tfid safety of transvenous hepatic biopsy in complicated hepatic disease. Clinical Research 29 313A.
cm 003089
PROGRAM I
THE STUOY OF TISSUE DISPOSITION OF INDUSTRIAL CHEMICALS: THE VINYL CHLORIDE EXAMPLE; Investigators - W.J. Waddell and C. Marlowe
II. The Use of Whole Body Autoradiography in Specific Tissues. Localization of Accumulated and Retained Industrial Chemicals and Their Metabolites
Background
Vinyl chloride has been classified by regulatory agencies as a carcinogen. Chronic exposure of workers to this carcinogen has resulted in angiosarcoma of the liver, as well as other tumors (Creech and Johnson, 1974). Several types of tumor also are observed after vinyl chloride exposure to animals (Maltoni and Lefemine, 1974). How or why these various body sites developed tumors was unclear. The need for methods which more accurately identify the sites of localization of chemical agents and their metabolites has obvious importance. The use of whole body autoradiography to identify the ultimate location of radioactively tagged chemicals was studied utilizing 14C-vinyl.chloride.
Objective
1. To determine the sites of localization and retention of the metabolites of vinyl chloride in mice.
2. Identification of the tissues of localization should help elucidate the mechanism of carcinogenic action of vinyl chloride.
Research Results
The sites of localization of radioactivity in tissues of the mouse following exposure to ^C-vinyl chloride were studied by the technique of whole-body autoradiography (Waddell and Marlowe, 1977). Male CD-I mice purchased from Charles River, weighing 25-31g., were exposed to '^C-vinyl chloride in room air in a sealed chamber for 3 hours. The radioactive vinyl chloride was synthesized from <4C-ethylene dichloride (New England Nuclear, Lot ol194-143, specific activity 3.2 mCi/mmole) imnediately prior to exposure by the method of Wagner et al. (1975). The initial concentration of the vinyl chloride was 50 ppm with a specific activity of 1.84 mCi/mmole. At the end of the 3 hour exposure of the mice to '^C-vinyl chloride the mice were removed to room air. Twenty minutes, 1, 3, 9 or 24 hours after removal of the mice to
92
CMA 003090
93
v*. b*-!afly anestnesized with ether and i-i/.'.s.tine bath at -75*C.
T .e .jr-^irazicn of cha radioac:ive vinyl chloride, exposure of the mice to this isotooic gas, and the sacrifice of the mice were done in collaboration with Or. william T. Stott at Oow Chenical in Midland, Michigan. All remaining procedures were performed at the University of Louisville.
wnole-oody sagittal sections of the mice, 20u- and 40y- thick were taken onto Scotch tape at -20*C. After freeze-drying, these sections were placed against Kodak AA X-ray film and allowed to expose in light-tight containers at -14*C for 6 to 39 weeks. The sites of localization of all nonvolatile metabo lites of vinyl chloride were visualized in the developed X-ray film (auto radiograph) and reveals the _i vivo disposition of these metabolites at the time of sacrifice of the mouse.'".These procedures for whole-body autoradi ography, first described by U11 berg in 1954 do not allow thawing or contact with any solvents. Thus, there is no translocation nor loss of radio activity. A complete description of these procedures have been published previously (Waddell and Marlowe, 1977).
Representative autoradiographs from each mouse were used as negatives to produce the prints included with this report. Therefore, white areas in the prints represent the sites of radioactive accumulation of the nonvolatile metabolites of '4C-vinyl chloride.
The highest levels of radioactivity in the mice sacrificed 20 minutes an<^^ 1 hour after removal from the T4C-v1nyl chloride environment were observed^P in liver, pancreas, kidney, intestinal contents, urine and bile (Figures 1 and 2). Additional sites of localization of radioactivity in the 1-hour animal were thymus, thyroid and seromucous glands (Figure 2).
The concentration of metabolites In the organs of excretion decreased continually over the 24 hour period (Figures 3-5). By 9 hours after removal from the vinyl chloride, thymus, Harder's gland, epithelium of the esophagus and Intestine, urine and sublingual gland retain the highest levels of radioactivity; moderate concentrations of radioactivity^ were observed in liver, kidney and intestinal contents (Figure 4). After 24'hours the primary organs of retentions of radioactivity were thymus and Harder's gland; some radioactivity could be visualized In liver and In esophageal and intestinal epithelium (Figure 5). Figure 6 shows the relative concentration of nonvolatile metabolites In the cortex and medulla of the thymus at the earliest and latest time Intervals studied. Twenty minutes after removal from the vinyl chloride, the concentration of radioactivity in the thymus was only slightly increased above that of blood (Figure 1 and 6); however, by 1 hour the thymus showed the highest uptake of radioactivity In the body (Figure 2) and remained the highest throughout the 24 hour period (Figures 2-6).
CMA 003091
l4C-VINYL CHLORIDE; 20 MIN AFTER REMOVAL
94
BRAIN
THYMUS LUNG
LIVER ADRENAL KIDNEY PANCREAS
NASAL EPITHELIUM
BLOOD
CONTENTS OF STOMACH AND INTESTINE
Figure 1:
A print of a whole-body autoradiograph from a Ml* CD-I mouse which was exposed for 1 hours to l^c-vinyl chloride and then froten 20 minutes after removal from the vinyl chloride environment. White areas correspond to radioactivity.
,4C-VINYL CHLORIDE; I HR AFTER REMOVAL
SEROMUCOUS GLAND THYROID BLOOD LUNg LIVER PANCREAS URINE
MINOR AND MAJOR SALIVARY GLANDS THYMUS BILE
CONTENTS OF INTESTINE
Figure 2:
A print of a whole-body autoradiograph from a male CD-I mouse whiph was exposed for 3 hours to 14C-vinyl chloride and then frozen' 1 hour after removal from the vinyl chloride environment.
White areas correspond to radioactivity.
CMA 003092
SEROMUCOUS GLAND" THYMUS LIVER CONTENTS OF STOMACH ANO INTESTINE
Fi|ura ]: A print of a vholt-body autoradiograph from a mult CD-I mouaa which vaa axposad (or 3 Hour* to ^C-vinyl chlorida and chan froran 3 hour* if car raaoval r<m th vinyl chlorida mvirocwanc. uiiita araas corrtapond co radioactivity.
14C-VINYL CHLORIDE; 9 HR AFTER REMOVAL
HARDER'S GLAND SUBUNGUAL GLAND LIVER SPLEEN KIONEY PANCREAS
Fi(ura 4:
A print of a whole-body autoradiograph frum a mala CD-I mouse which wa* uapoaad for 3 houra to Uc-vinyi chlorida and then croton 9 hours aftar ronoval from the vinyl'chlorida environment. Uhita araaa correspond to radioactivity.
CMA. 003093
l4C-VINYL CHLORIDE; 24 HR AFTER REMOVAL
HARDER'S GLAND
BLOOD
KIDNEY
PANCREAS
96
VIBRISSAL FOLLICLES
THYMUS
tlVER
Figura 5:
A print of a whole-body autoradiograph from a male CD-I mouse which waa exposed for 1 hour* to *4C-vinyl chloride and then frozen 24 hours after removal from the vinyl chloride environment.
White areas correspond to radioactivity.
,4c-vinyl chloride
20 MIN AFTER REMOVAL
24 HR AFTER REMOVAL
CORTEX AND MEDULLA OF THYMUS
CORTEX AND MEDULLA OF THYMUS
Figure 6:
Prints of the thymus areas of whole-body autoradiographs from male CD-I mice which were exposed to ^"C-vlnyl chloride for 1 nours and then frozen 20 minuces or 24 hour* after removal from the vinyl chloride environment. White areas correspond to radioactivity. Note the high retention of the nonvolatile metabolites in the cortex of the thymus after 24 hours.
CMA 003094
97
in z'r.s ~ny~us aftar 24 hours suggests that there is covalent binding of these
metabolites to molecules in the thymus. It is possible that these molecular interactions in the thymus could have an effect on the immune system. The high concentration in the thymus may be involved in the stimulation of the immune system in mice seen by Sharma and Gehring (1979) and in the reduction
in peripheral T-lymphocytes seen in man by Ward et al. (1976).
Vinyl chloride may exert its carcinogenic action by a dual mechanism. It
may suppress the iimune surveillance system mediated by the thymus and concurrently damage several tissues including the liver.
Fals'/ancs to Industry
Whole-body autoradiographic studies on the biological disposition of industrial chemicals offers the most thorough approach to the study of the interaction of these chemicals with tissues in the body. Knowledge of these tissue interactions allows predictions of potential toxicity or, conversely, to a lack of toxic effect if the chemical is rapidly and completely eliminated (Waddell et al., 1977). When chemicals are retained in specific tissues as.in the case with vinyl chloride, the tissue of retention gives an indication of possible mechanisms of toxic action. Vinyl chloride appears to be having a toxic effect on the immune system; the direct evidence for an interaction of the chemical with this system was not available until these studies were done.
References
Creech,J.l. and Johnson, M.N. (1974) Angiosarcoma of liver in the
manufacture of polyvinyl chloride. Journal of Occupational Medicine
J6: 150.
---------------------------------------------------
Duprat, P., Fabry, J.P., Gradlskl, 0. and Magadur, J.L. (1977) Metabolic
approach to Industrial poisoning: blood kinetics and-'distribution of ]Z*C~vinyl chloride monomer (V.C.M.) Acta Pharmdcolody and Toxicology 1:142.
Maltonl, S. and Lefemine, G. (1974) Carcinogenicity bioassays of vinyl
chloride. Research plan and early results. Environmental Research
h 387.
-----------------------------------
Sharma, R.P. and Gehring, P.J. (1979) Immunologic effects of vinyl chlo ride in mice. Annals New York Academy of Science. 320:551.
Ullberg, S. (1954) Studies on the distribution and fate of S^S-iabelled ben2ylpenicillin in the body. Acta Radiology. Supplment 118:1.
00395
X
i 98 i^-wyjPHnd Marlowe, C. (1977) Autoradiography. IN: Garrett, E.R. and Hirtz, J.L. (eds.), Drug Fate and Metabolism: Methods and Techniques. Vol. 1, pp. 1-2^. New Yorlc: Marcel Dekker. Waddell, W.J., Marlowe, C., Miripol, J.E., and Gravin, P.J. (1977) The distribution in mice of intravenously administered plasma solutions of [l*C]Di-2-Ethyl hexyl Phthalate Determined by Whole-Body Autoradiography. Toxicology and Applied Pharmacology 39:339-353. Wagner, E.R., Muelder, W.M., Watanabek, P.G., Hefner, R.E., Jr., Braun, W.H. and Gehring. P.J. (1975) A gas chromatographic method for the preparation of '^c-labelled vinyl chloride. Journal of Labelled Compounds XI (4):535. Ward, A.M., Udnoon.S., Watkins, J., Walker, A.E. and Darke, C.S. (1976) Immunological mechanisms in the pathogenesis of vinyl chloride disease. British Medical Journal, 1:936.
CAt* 309s
LISTS OF PUBLICATIONS, ABSTRACTS, PREPRINTS AND PUBLICATIONS IN PREPARATION
99
CMA 003097
100
PUBLICATIONS
1. Fortwengler, Jr., H.P., Jones, 0., Espinsoa, E. and Tamburro, C.H. (1981)
Evidence of Endothelial Cell Origin of Vinyl Chloride-Induced Hepatic Angiosarcoma. Gastroenterology, 80:1415-1419.
2. Du, J.T., Sandoz, J.P., Tseng, M.T. and Tamburro, C.H. (1979) Biochemical
Alterations in Livers of Rats Exposed to Vinyl Chloride. Journal of Toxicology and Environmental Health, j>:1119-1132.
3. Tamburro, C.J. (1978) The Hepatic Role in Carcinogenesis and Its Early Detection--The Vinyl Chloride Model. The Yale Journal of Biology and Medicine, Inc., 51:67-80.
4. Du, J.T., Tseng, M.T, and Tamburro, C.H. (1982) The Effect of Repeated Vinyl Chloride Exposure on Rat Hepatic Metabolizing Enzymes. Toxi
cology and Applied Pharmacology, 62:1-10.
5. Tamburro, C.H. and Greenberg, R.A. (1981) Effectiveness of Federally
Required Medical Laboratory Screening in the Detection of Chemical Liver Injury. Environmental Health Perspectives, 41:117-122.
6. Curran, K.L., Kupchella, C.E. and Tamburro, C.H. (1977) Urinary Glyco-
saminoglycan Patterns in Anqiosarcoma of the Liver. Cancer, 40:
3050-3053.
"
7. Kupchella, C.E. and Tamburro, C.H. (1978) Urinary and Tissue Glycosamino-
glycan Patterns in Hepatic Angiosarcoma. Detection and Prevention of Cancer, H.E. Neiburgs, Ed., Part 1, Vol I, Marcel uekker, Tnc77 New York.
8. Kupchella, C.E., Drake, E.E., Kennedy, J., Curran, K.L., Warick, R. and
Morris, H.P. (1981) Tissue and Urinary Glycosaminoglycan Patterns Associated with a Fast, an Intermediate, and a Slow-growing Morris Hepatoma. Cancer Research, 41:419-424.
9. Tamburro, C.H., Kupcnella, C.E. and Greenberg, R.A., et al. (1981) Screening for the Early Detection of Disease in Individuals Exposed
.to Vinyl Chloride. U.S. Environmental Protection Agency, 560/6-81-
002
10. Laumbach, A.D., Lee, S., Wong, J. and Streips, U.N. (1976) Studies on the
Mutagenicity of Vinyl Chloride Metabolites and Related Chemicals. Prev., Detect. Cancer (Proc. Int. Symp.) 3rd, Vol. 1:155-170.
11. Elmore, J., Wong, H., Laumbach, A.D. and Streips, U.N. (1976) Vinyl
Chloride Mutagenicity and Carcinogenicity via the Metabolites Chlorooxirane and Chloroacetaldehyde Monomer Hydrate. Biochem.
Biophys. Acta 442:405.
CMA 003098
12. Streios,.U.N., Laumbach, A.O. a"d
,; T 0 3 1 \ 0 ^ ^ y* - ^ ^
. Mutation Monitor for Active Metaoolit ss of Chemical Car; 8. Subtilis Assays for Mutation and t4 v n )--*<1*1,C | *ii*i '. i c .'C a i a i
Testers. T. Cecil Felkner, Ed., Vol. 5, Marcel DekkeTT I nc.. New
York.
13. Horowitz, S., Doyle, R.J., Young, F.E. and Streips, U.N. (1981) Selective Association of the Chromosome with Membrane in a Stable L-Form of Bacillus Subtilis. Journal of Bacteriology, 138:915-922.
14. Streips, U.N., Horowitz, S. and Doyle, R.J. (1980) Genetic Analysis of DNA-Surface Interactions in Bacillus Subtilis. Microbiology:284-287.
15. Horowitz, S., Doyle, R.J. and Streips, U.N. (1978) Restricted Chrrwjscmo-
Membrane Association in a Stable L-form of Bacillus Subtilis. In Transformation. 1978. Proceedings of the Fourth InternaticnTT Meeting on Bacterial Transformation.
16. Sonnenfeld, G., Barnes, M.C., Schooler, J. and Streips, U.N. (1980)
Inhibition of Interferon Induction as a Screen for the Carcinogenic Potential of Chemicals, _l Interferon: Properties and Clinical Uses. A. Khan, N.O. Hill and G.L. Dorn, Eds. pp. 589-598, Wadley Institutes of Molecular Medicine, Dallas, Texas.
17. Barnes, M.C., Streips, U.N. and Sonnenfeld, G. (1981) Effect of Car cinogens and Analogs on Interferon Induction. Oncology 38:98-101.
18. Espinosa, E. (1976) Iraiuinopathologic observations in liver angiosarcoma.
In Prevention and Detection of Cancer, Vol. 1, Neiburgs, H.E., Ed. pp. 927-36, Marcel Dekker, Inc., New York.
19. Espinosa, E. Circulating Tissue Antigens. (1976) Identification and
Characterization of Antigens of Limited and of Wide Body Distribution in Human Gall Bladder Bile. Clin. Exp. Innunol.,
25:410-417.
-------------- -----------------
102
ABSTRACTS
1. Fortwengler, H.P., Dever, M.E., Tamburro, C.H., and Espinosa, E. (1978). Lymphocyte transformation tests in vinyl chloride workers. Fed. Proc., 37: 362.
2. Fortwengler, H.P., Jones, D., Tamburro, C.H. and Espinosa, E. (1979). Factor VIII content as evidence for endothelial origin of vinyl chloride associated liver angiosarcoma. Fed. Proc., 38:999.
3. Fortwengler, H.P. and Tamburro, C.H. (1976). Use of dye clearance in the detection of hepatocellular injury among vinyl chloride workers. Clin. Res., 23:264A.
4. Du, J.T. and Tamburro, C.H. (1976). Decreased glucose-6-phosphatase activity in liver in vinyl chloride exposed rats. Fed. Proc., 35:1422.
5. Du, J.T. and Tamburro, C.H. (1978). Elevated glutathione content, glutathione-S-transferase and glutathione reductase in liver of rats exposed to vinyl chloride. Fed. Proc., 37:1545.
6. Liss, G. and Tamburro, C.H. (1982). Serum bile acids in screening for chemical hepatoxlcity. The Toxicologist, July 1982. -
7. Kupchella, C.E., Jarvis,J.O., Curran, K.L.,
Greenberg, R.A. and
Tamburro, C.H. (1977). Tissue and urinary glycosamtndgTycan changes in
hepatic fibrosis. Gastroenterology, 73:1299.
8. Kupchella, C.E. and Tamburro, C.H. (1977). Urinary chrondroitin sulfate fraction patterns in hepatic angiosarcoma. Clin. Res., 25:35A.
9. Kupchella, C.E, and Tamburro, C.H. (1977). Urinary glycosaminoglycan
exenetten patterns In chenrtcally induced liver Injury and cancer. Clin.
Res., 25, 329.
i
10. Kupchella, C.E. and Curran, K.L., Drake, E., Kennedy, J. and Tamburro, C.H. (1978). Tissue and grinary glycosaminoglycans in transplantable
hepatomas. Gastroenterology^ 75:972.
11. Curran, K.L^, Kupchella, C.t., Sandoz, J. and Tamburro, C.H. (1978). urinary glycosaminoglycan patterns in human hepatic angiosarcoma, hepatoma, and In workers at risx for angiosarcoma. Gastroenterology, 75:959.
12. Kupchella, C.E., Secskas, E.M., Kenndy, J.S., and Espinosa, E. (1979). Glycosaminoglycan changes associated with hepatic tumors: The contributions of regeneration and necrosis. Clin. Res., 27:389.
0*4 003loo
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14. Sorrows, S.H., Joyce, M.J., Schrodt, G.R., Greenberg, R.A. and Tamburro, * C.H. (1S79). Computer-assisted morphologic quantitation of collagen in human liver biopsies. Laboratory Investigations, 40:3.
15. Tamburro,C.H., Male*. L.
and Popper, H. ( 1979). Early hepatic
histological alterations among chemical (vinyl monomer) workers.
Gastroenterology, 77:A33.
16. Laumbach, A.O., Streips, U.N. and Wong, J.L. (1978). Chloroacetaldehyde-induced damage to Bacillus subtilis. Ann. Mtq. Amer. Son. Microbiol., o. 125.
17. Streips, U.N. and wong, J.L. (1978). Chloroacetaldehyde-induced damage to Bacillus subtilis. XII Intern. Congress Microbiol., p. 105.
18. Sonnenfeld, G., Samss, M.C. and Streips, U.N. ( 1979). Inhibition of interferon induction as a screen for the carcinogenic potential of chemicals. J, Clin. Hematol. and Oncol., .9:291.
19. Johnston, P.8., Espinosa, E., Chia, S. and Caple, S. Properties of 14 week maintenance cultures of PLC/PRF/5 cells. In Vitro, 15:227.
20. Espinosa, E., Chia, S., Caple, S. and Kupchella, C.E. (1979).
Liver-specific F antigen in transplantable hepatomas having different growth rates. Fed. Proc., 38:1069.
21. Espinosa, E., Caple, S.t Kupchella, C.E. and Chia, S. (1979). Two liver antigens undetectable in a fast growing line of transplanted hepatoma (Morris Hepatoma 7777). Fed. Proc., 1069.
22. Du, J.T. and Tamburro, C.H. (1980). Oxidative and detoxifying ability of
liver mesenchymal vs. parenchymal cells in the metabolism of xenobiotics. Gastroenterology, 79:1013.
23. Liss, G. and Tamburro, C.H. (1982). Toxic carcinogenic and safe exposure
levels in vinyl chloride-induced hepatic angiosarcoma. Toxicologist,
July 1982.
-------------
CMA 003101
104 PREPRINTS 1. Tamburro, C.H., Makk, L. and Popper, H. Early Hepatic Histological Alterations among Chemical (Vinyl Honomer) Workers. 2. Du, J.T., Eades, O.S., and Tamburro, C.H. Oxidative and GlutathioneRelated Detoxifying Enzyme Capabilities in Hepatocytes and Nonhepatocytes of Rat Liver. 3. Kupchella, C.E., Greenberg, R.A. , Warick, R.A. and Tamburro, C.H. Preliminary Assessment of the Usefulness of Urinary Total Glycosaminoglycan.
CMA 003102
to
1; ^
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1. Tamburro, C.-., Wilis', 3. and Grear.targ, S Specificity of ICG Clearance TEst of Hepatotoxicity.
C.i l w i * w*
nd
2. Tamburro, C.H., Miller, 8. and Chan, C. Indocyanine Green (ICG) Clearance Test Safety and Toxicity.
3. Fortwengler, P. and Tamburro, C.H. Use of HIA Tissue Typing in the Identification of Chemical Injury in Vinyl Monomer-Exposed Workers.
4. Fortwengler, P. and Tamburro, C.H. Immunocompetence of Humans Chemically Exposed to Finyl Monomer Chemical.
5. Barrow, G., Scr.rcct, G.R. and Tamourro, C.H. Collagen Changes in normal Aging Liver.
CMA 003103
APPENDIX
106
003^4
PUBLICATIONS
CMA 003105
GASTROENTEROLOGY 19*1*03413-19
1
Evidence for Endothelial Cell Origin of Vinyl Chloride-Induced Hepatic Angiosarcoma
H. PHILIP FORTWENGLER, JR., DOUGLAS JONES, ENRIQUE ESPINOSA, and CARLO H. TAMBURRO
Department of Medicine. Division of Digestive Diastase and Nutrition, Department of Pathology and Cancer Canter, University of Louisville School of Medicine, Louisville, Kentucky
Previous reports of hepatic angiosarcoma have not clearly defined the cellular type from which this tu mor arises, as evidenced by the terminology of endo thelioma, Kupffer cell sarcoma, endothelial cell sar coma, and hemangioendothelial sarcoma, etc., tvhieh have been used interchangeably. In addition, there has been no consensus on the separate entity of Kupffer and sinusoidal endothelial cells. In the work presented here, evidence for the endothelial cell origin of this tumor is provided by the demon stration of factor VIII, a known endothelial cell marker, in the tumor cells. Fluorescence due to the presence of factor VUl appeared intense in the tu mor sinusoidal cells of all four vinyl chloride-associ ated angiosarcomas studied, whereas normal liver sinusoidal lining cells showed negligible fluores cence.
Hepatic angiosarcoma has been associated with ex posure to thorotrast (1). arsenic (2), androgenic-ana bolic steroids (3), and vinyl chloride (4). However, most cases are of undetermined origin. Regardless of etiology, earlier studies (5-8) made no clear dis tinction between endothelial and Kupffer ceils, and gave various histologic designations to this type of tumor, e.g,, hemangioblastoma, Kupffer cell sar-
Received April 22. lflSO. Accepted January 12.1961. Address requests for reprints tor Carlo H. Temburro, M.D.. Di vision of Digestive Diseases and Nutrition, Department of Medi cine. Health Sciences and Cancer Center, University of Louisville, Louisville. Kentucky 40292. This investigation was supported by a Research Grant from the Manufacturing Chemists Association. This work was presented in part at the Federation of American Societies for Experimental Biology masting in Dallas. Texas in April 1979. The technical assistance of Mr. Larry Wilder is greatly cknowledged. We would like to thank Dr. Hans Popper for his re view of the histology and his suggestions.
19S1 by the American Gastroenterological Association 0016-S083/8VOS14154SS02JO
coma, angiosarcoma, and endothelioma (9), thus raising the question of its true cellular origin. This question is of particular current interest in view of recent findings by electron microscopy which clearly support a distinct origin for Kupffer and endothelial cells (10), as well as indicating the ab sence of endothelial cell to Kupffer cell transition
(ID*
Factor VIU, a coagulation factor, was shown by Hoyer et aL (12), to be present in endothelial cells, megakaryocytes, and platelets. In the work pre sented here, using immunochemical evidence, the presence of abundant factor VIII in proliferating si nusoidal lining cells of angiosarcomatous liver tissue is demonstrated; it supports the endothelial cell ori gin of vinyl chloride-associated angiosarcoma.
Materials and Methods
Hepatic tissue studies wen conducted in eight in dividuals--^hree with hepatic angiosarcoma related to heavy vinyl chloride exposure is production workers, one hepatic angiosarcoma associated with vinyl chloride used as hair spray propellant, and four normal subjects (trau matic death with no liver injury) who wen used as con trols.
Reagents. Purified human factor VIII was pro vided by the Louisville Red Cross Blood Center. Corre sponding antiserum prepared in rabbits was from Behring Diagnostics (American Hoechst Corp., Somerville. N.J.). A single precipitin line in Immunoelectrophoresis was seen with this material when tested against human plasms and purified factor VIII. Fluorescein-conjugated goat anti serum to rabbit IgG (GARI) was obtained from Meloy Lab oratories, Inc. (Springfield. Va.).
Tissue specimens. Both normal and hepatic angio sarcoma tissue were obtained at postmortem examination within 30 min to 8 h of death. Portions of normal and tu mor tissues were processed for standard histologic and immunofluorescent staining.
Immunofluorescence technique. Frozen sections (B
CMA 003106
1
1416 FORTWBNGISR ET A?
/im) were cut on a cryostat. air dried, fixed for 5 min in cold acetone and rehydrated in photphate-buffered saline (PBS). The sections wan then treated for 30 min with anti serum to factor Vin. washed with PBS, and stained with fluorescein-conjugated GARI for 45 min. After three 5-min washes in PBS, the sections were examined by immunofluorescent microscopy utilizing a Vanox microscope (Olympus Corporation of America), and an HB0200 UV il luminator with a 3-mm BP 12 excitor filter and a G530 bar rier filter. Control sections were incubated with nonimmunized rabbit serum. Specificity of factor VIII staining was demonstrated by inhibition of the staining reaction after absorption of the anti-factor VIII rabbit serum with the purified factor VIII and by the negative staining reaction found using nonimmune rabbit serum.
Resuits
Factor VIII immunofluorescence of endo thelial cells in human umbilical cord shows a ho mogeneous continuous staining pattern (Figure 1). This preparation served as a positive control. Sec tions from normal liver did not display any specific factor VIII immunofluorescence in the sinusoidal
GASTROENTEROLOGY Voi- 80. No. 8
Tl
Figure t. Umbilical cord, endothelial lining cells (arrows) show ing factor VIU related immunofluorescence in white (x 100).
Figure 2. Fluorescent stabling of normal liver showing minimal granular punctate factor VIII fluoracaoce in hepatic ilnuaoids (white arrows) (x 100).
areas except for occasional spotty granular areas of minimal intensity along the sinusoidal borders (Fig ure 2). Only the linings of the hepatic arteries and veins consistently gave intense staining reactions. In contrast, vinyl chloride hepatic angiosarcoma tumor tissue demonstrated' intense fluorescence occurring in the proliferating cells lining the enlarged sinu soids (Figure 3). These areas of specific immuno fluorescence were limited to the sinusoidal spaces, were multifocal and occasionally occupied up to 20% of the tissue specimen. There was no demonstrable difference among the four angiosarcoma specimens as to the frequency of stained cells or the pattern of specific fluorescence. Adjacent tissue stained with H & B documents angiosarcomatous cells within the enlarged sinusoids lining the hepatocytic cords (Fig ure 4).
Fluorescence was present in the cytoplasm and cell surface but not in the nuclei of the sinusoidal cells as illustrated in Figure 5. This distinguishable pattern of factor VIII immunofiuorescent staining was seen in all the angiosarcomas examined and in none of the normal hepatic tissue.
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described it as composed of ceiis ciostiy rcssmbiing Kupffcr colls and indicated that some tumor cells
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sinusoidal lining cells, i.e. "Kupffer cells" and "nor
mal resting sinusoidal endothelia." He noted that the
tumor cells were phagocytic and therefore, de
scribed the tumor as originating from Kupffer ceils,
as did Burster. (17). Edmonson's classical ucacripuon
of this tumor (9) makes no distinction between endo
thelial and Kupffer cells, but describes it as com
posed of malignant endothelial cells.
In the initial report of arsenic-associated "heman-
gioendothelial sarcoma" of the liver due to ingestion
of Fowler's solution, Regelson et al. (18), indicated
the presence a: neoplastic endothelial ceils bui did
not differentiate Kupffer from endothelial ceils. On
the other hand. Blackwell et al. (19), made no dis-
Figure 3. A section of llv angiosarcoma tiaaue exhibiting one of the muitifocei Meat diapiaying markad fiuoreacence in the proliferating sinusoidal ceils (white arrows), with some nonspecific background staining of hepatocytes
(x 700).
Discussion
Descriptions and definitions of hepatic angio sarcoma have varied in the past and have relied pre dominantly on morphologic criteria for identifying the various sinusoidal cells.
Some investigators have proposed that both Kupf fer and sinusoidal endothelial cells are transitory in respect to each other and that Kupffer cells merely represent activated endothelial ceils (5.13). In con trast, others support the view that the Kupffer cell is independent in nature and represents a hepatic macrophage (14.15).
As early as 1939, Miller considered the Kupffer cell as a class of endothelial ceils and distinguished them as "endothelial cells of Kupffer (13)." He sug gested the term endothelioma or endothelioblastoma for the tumors arising from Kupffer cells and heman gioendotheliomas or hemangioendothelioblastoma for those derived from vascular endothelium. In the first communication of a thorotrast-associated ma lignant hepatic vascular tumor. McMahon et aL (1).
\.
Figure 4. A (mm action of hepatic angiosarcoma tiaauo dataonatniiitf individual and (mail group* of proiifarating endothelial cslla in dilated tinuaotd* (Mock arrow*) (H a E x 400).
CMA 003108
1418 FORTWENCLER ET AL
GASTROENTEROLOGY Vol. 8a No. 8
Kupffcruccfty1 which arc peroxidase positive and phagocytic.
In the present work we have shown by an immunofluorescent procedure that Factor VIII is present in the proliferating cells of vinyl chloride-associated angiosarcoma, thus confirming their endothelial cell origin. Our observation that normal hepatic tissue displays intense factor VIII fluorescence in cross sections of vessels, but limited fluorescence of the si nusoidal endothelial cells in comparison to angiosarcomatous tissue, suggests that the aberrant cells may have an increased production or storage capac ity for factor VIII qr a decreased transport from the cell. In addition, staining for factor VIII may provide a means for identification of vascular cell in volvement in hepatic tumors and could be used to identify specific endothelial cell changes and their relationship to chemical biotransformation in both animals and humans.
In view of these findings, we suggest that the term "endothelial cell angiosarcoma" be used as an ap propriate term for this tumor.
References
Figure 3. High-powered frozen section of angiosercomatou* tis sue showing factor VIII immunofluorescence of indi vidual proliferating calif lining hepatic corda (white ar row*). Fluorescent staining of cytoplasm but not cell nucleus is seen in one of the cells (x 1000).
tinction between these cells but called the tumor Kupffer cell sarcoma.
In more recent reports involving vinyl chloride-as sociated angiosarcoma, the question of cellular ori gin of the tumor persists. This malignancy has been variously described as pleomorphic malignant endo thelial cells (9), malignant spherical and spindle cells (20), "tumor cells" (21), sinusoidal cells (22), and as a tumor believed to be malignant Kupffer cells (23). Makk et aL (24) and Popper et aL (25) depicted this tumor as arising from sinusoidal endothelial cells.
In comparing the pathology of liver angiosarcoma due to vinyl chloride, thorotrast, and arsenic. Popper et al. (25) concluded from light and electron micros copy that the tumors were probably endothelial and suggested confirmation by use of histologic markers. An appropriate marker which concentrates in the endothelial cells is provided by coagulation factor VIII which differentially appears in the endothelial cells, megakaryocytes and platelets (12) and not in
1. MscMahon HE, Murphy AS, Bates ML Endothelial-cell sar
coma of liver following thorotrast injections. Am I Pathol 1947:23:388.
2. Roth F. The sequelae of chronic arsenic poisoning in moselle vintner*. Ger Med Mon 1957:2:172.
3. Fsik H. Popper H. Thornes LB. ft al. Hepstic sngiossrooms sssocisted with androgenic-anabolic steroids. Lsncet 1979dfcim
4. Creech JL fohnson MN. Angiosarcoma of the liver in the manufacture of polyvinyl chloride. | Occup Med 1974:10:150
5. Cibbe WN, Connor CR. Hutchison HE Meiignant hemangio endothelioma associated with thrombocytopenia. | Pathol Bsct 1988:92:207.
8. MacSwoen RNM. Vetter* |M, Roee SIC et aL Haemangiocndothelial sarcoma of the liver, f Pathol 1973:109:39.
7. Stout AP. Hemangio-endotheiloma: a tumor of blood vessels featuring vascular endothelial cells. Ann Surf 1943:118:445.
8. Greenberg M. Kupffer ceil sarcoma of the liver. Report of 2 cases id South African blacks. SA Med | 1977:82:244.
9. Edmonson HA. Tumors of the liver end intrahepatic bile ducts. Atlas of Tumor Pathology, Section 7, Fsscile 25, Washington. D.C, Armed Forces institute of Pathology, 1958:13945.
10. Van Furtb R. et al. The bona marrow origin of Kupffer cells. In: Wiese E, Knook DL eds. Kupffer cells and other liver si nusoidal cells. Amsterdam: Elsevier/North Holland, 1977:471.
11. Wieae E, Knook DL The investigation of sinusoidal calls: s new approach to the study of liver function. Prog Uver Die 19708:183.
12. Hoyer LW. de los Santoe RP. Hoyer JR. Antihemophilic factor antigen. Localization in endothelial cells by immunofluoraacent microscopy.) Clin Invast 1973:53:2737.
13. Millar |K. Primary sarcoma of the liver endotheiioblastoma.
Am | Surg 1939:45:459. 14. Wiese E. Ullrastructure and function of Kupffer cells and
other sinuaoidai cells in the liver. In: Wisse E. Knook DL eds.
CMA 003109
,'uflS .3
CELLULAR ORIGIN OF HEPATIC .ANGIOSARCOMA 1417
described it as composed of ceils closely resembling Kupffer cells and indicated that snme tumor cells wore phagocytic. Ntver*h,'i!:e. the tumor was desig nated "endothelial ceil sarcoma of the liver." Later, in reporting a tumor. Baker et aj. (16), made a dis tinction between the apparent maturation stages of sinusoidal lining cells, i.e. "Kupffer cells" and "nor mal resting sinusoidal endothelia," He noted that the tumor cells were phagocytic and therefore, de scribed the tumor as originating from Kupffer cells, as did Burston (17). Edmonson's classical description of this tumor (9) makes no distinction between endo thelial and Kupffer cells, but describes it as com posed of malignant endothelial cells.
In the initial report of arsenic-associated "hemangioendothelial sarcoma" of the liver due to ingestion of Fowler's solution. Regelson et al. (18). indicated the presence of neoplastic endothelial cells but did not differentiate Kupffer from endothelial cells. On the other hand. Blackwell et al. (19), made no dis-
figure 3. A section of liver angiosarcoma tissue exhibiting one of the multifocal areas displaying marked fluorescence in the proliferating sinusoidal cells (white arrows), with some nonspecific background staining of hepatocytea (X 300).
Discussion
Descriptions and definitions of hepatic angio sarcoma have varied in the past and have relied pre dominantly on morphologic criteria for identifying the various sinusoidal cells.
Some investigators have proposed that both Kupffer and sinusoidal endothelial cells are transitory in respect to each other and that Kupffer cells merely represent activated endothelial cells (5,13). In con trast, others support the view that the Kupffer cell is independent in nature and represents a hepatic macrophage (14,15).
As early as 1939, Miller considered the Kupffer ceil as a class of endothelial cells and distinguished them as "endothelial cells of Kupffer (13)." He sug gested the term endothelioma or endotheliobiastoma for the tumors arising from Kupffer cells and heman gioendotheliomas or hemangioendothelioblastoma for those derived from vascular endothelium. In the first communication of a thorotrast-associated ma lignant hepatic vascular tumor, McMahon et al. (1),
Pfgura i A frozen section of hepatic angiosarcoma tissue dem onstrating individual end small group* of proliferating endothelial call* in dilated sinusoids (block arrows) (H k E x 400).
CMA 003110
June ifllll
CELLULAR ORIGIN OF HEPATIC ANGIOSARCOMA 1419
Kupffer coll* and other liver sinusoidal colls. Amsterdam: Elscvicr/North Holland. 1977:33.
15. Naito M. Wises E. Observations on the line structure and cytochemistry of sinusoidal cells in fetal and neonatal rat
liver. In: Wisae E. Knook DL, ads. Kupffer cells and other liver sinusoidal cells. Amsterdam: Elsevier/North Holland. 1977:497. 16. Baker H de C. Paget GE, Davson I. Hemangioendotheliomas (Kupffer-ceil sarcoma) of the liver. | Pathol Bact 1956:72:173. 17. Burston Kupffer cell sarcoma. Cancer 1950:11:796. 18. Regelson W, Kim 17, Ospino J, st al. Hemangioendothelial sar coma of liver from chronic arsenic intoxiftestion by Fowler's solution. Cancer 196821:514. 19. Blackwell fB, Joske RA. Kupffer cell sarcoma. Dig Dis 1970:15:133.
20. Lee FI, Harry DS. Angiosarcoma of the liver in a vinyi chlo ride worker. Lancet 1974;i:1316.
21. Pollard SM. Millward-Sadler GH. Malignant haemangioendothelioma involving the liver. J Clin Pathol 197427:214.
22. Thomas LB, Popper H. Berk PD. et al. Vinyl chloride-induced liver disease. N Engl I Med 1973:292:17.
23. Smith PM. Williams M|, Evans DMD. Hepatic angiosarcoma in vinyl chloride workers. Bull NY Acad Med 1976:52:447.
24. Makk L Delmore F, Creech JL Jr. et aL Clinical and morpho logic features of hepatic angiosarcoma in vinyl chloride workers. Cancer 1976:37:149.
25. Popper H, Thomas LB. Telles N. et al. Development of hepatic angiosarcoma in man induced by vinyl chloride, thorotrast, and arsenic. Am J Pathol 197822:349.
CMA 003111
2
BIOCHEMICAL ALTERATIONS IN LIVERS OF RATS EXPOSED TO VINYL CHLORIDE
Julie T. Du, John P. Sandoz, Michael T. Tseng, Carlo H. Tamburro
Division of Digestive Diseases and Nutrition, Department of Medicine, Department of Anatomy, and Cancer Center, University of Louisville School of Medicine, Louisville, Kentucky
' Sprague-Dawtey rats were txposrd to vinyl chloride to determine tilt tatilest sequentid biochemical changes occurring with liver injury before engiomrcom* development. Activity of glucose-6-phosphatase, t kty gluconeogenic tnzyme in the liver microtome! (ruction, decreused 2SfS with respect to controls efter 70 h of exposure. Glucoie-6phosphote dehydrogenase activity Increased twofold efter more then 100 h of exposure. Nonprotein sulfhydryl levels (glutathione end/or cysteine) showed a slight but progressive devotion, whereas glututhlont reductase activity increased SO-fOK during exposure to vinyl chloride. NAOMcytoehrome c reductase and mixed function oxidase were unchanged in the same microsomal fraction. There were no changes In seven conventional clinical biochemical Over tests or hi four other mothers of liver mitochondrial, cytosol, and microsomal (Unction. No significant histological changes were found on light microscopic examination during this exposure period. However, with electron microscopy, dilation of rough endoplasmic reticulum was seen in the animals exposed for more than 137 h. These eneymaUc changes are considered to reflect early hepatocellular adaptation to vinyl chloride exposure with my mUd or limited hepatocellular Injury In Its earliest stage.
INTRODUCTION
Vinyl chloride has been shown to induce tumors, including angio- sarcoma, in laboratory animals (Maitoni and Lefemine, 1975; Viola et al., 1971) and angiosarcoma in humans (Creech and Johnson; 1974). At high concentrations, vinyl chloride is believed to be metabolized by the microsomal mixed function oxidase (MFO) system of the liver to toxic metabolites (Bolt et al., 1975; Hefner et al., 1975; johnson, 1967; Watanabe et al., 1976b, 1976c). Animals pretreated with phenobarbetal, an inducer of
We wish to express our sincere thanks to the paopla in the B. F. Goodrich plant In LouUvilli^^ for thoir cooperation in tho exposure studies. Or. R. A_Greenberg for help with statistics. andFMs. Ruth Shelton for technical assistance.
This work was supported by a grant front the Manufacturing Chemists Association, Washing ton, D.C.
Requests lot reprints should be sent to Carlo H. Tamburro. Division of Digestive Diseases and Nutrition, Health Sciences Center, MOR 535, University of Louisville, Louisville, Kentucky 40332.
1119
Jotonal of Toxicology and Environmental Health, 511119*1133,1979 Copyright e 1979 by Hemisphere Publishing Corporation 0093-4101/79/051119-14*2.25
CMA 00313-2
1120
y J.T. OUST AL.
MFO, and exposed to 5% vinyl chloride (50,000 ppm) had increased serum
alanine aminotransferase, a conventional biochemical indicator of liver injury, and increased serum sorbitol dehydrogenase, a liver specific enzyme (Jaeger et al., 1974). However, there have been no sequential enzymatic studies to determine what progressive metabolic alterations of the hepatocytc occur during vinyl chloride exposure preceding the development of angiosarcoma. Although the hepatocyte is the major cell for oxidation and. probably detoxification of vinyl chloride and its metabolites, angiosaccoma develops not in the hepatocyte but in adjacent mesenchymal cells. During this time, the hepatocytes undergo changes (focal nodular hyperplasia) suggesting focal regeneration, probably from limited hepatocellular injury (Tamburro et al., 1979).
The purpose of our study was to characterize the earliest sequential enzymatic changes that occurred in vinyl chloride exposure to elucidate the hepatocytes* role in vinyl chloride-induced injury and angiosarcoma develop ment. Portions of this study have been presented elsewhere (Du and Tamburro, 1976).
METHODS
Animals and Experimental Design
Sprague-Dawtey male rats (300-500 g) were randomly assigned before each experiment to either a group to be exposed to vinyl chloride gas (15,000 ppm) or a nonexposed control group kept outside the chamber in the animal room. Animals were feef standard laboratory chow pellets ad. libitum.
Four sequential experiments were done. In experiments A and B, rats, were exposed 2-4 h/d, 4 d/wk, for 1-2 wk with total accumulated
exposure times of 14, 28, and 42 h. In experiment C, rats were exposed 4-8 h/d, 5 d/wk, for 2-3 wk with totai accumulated exposure periods of 71 and 103 h. In experiment D, rats were exposed 6-8 h/d, 5 d/wk, for 3-4 wk with" total accumulated exposure periods of 84 and 137
The animals were exposed in a modified chamber consisting of an airtight vat that had been used for manufacturing polyvinyl chloride. An aliquot-of vinyl chloride (185 g) was added to the vat per 4-d period to make an average concentration of 15,000 4000 ppm. The air was constantly circulated by a stirrer. The chamber volume was 4400 I (1100 gal), so the' respiration of the rats had a negligible effect on the composition of the chamber's atmosphere. Experiments with an added control group exposed only to air in an identical modified vac showed no differences from the controls kept in the animal*room (Table V).
All animals were anesthetized with ether, had blood drawn by cardiac puncture, and were sacrificed at the same time of day (within 3 h after final exposure) to avoid diurnal effects.
CMA 003113
VIVY'.'CHlStlPS Sfr~Z73 Q'l Z;
mi
7a3Ls 1. Compirtiofl at Ntpilie Entym* Acti\i(Ui in Animal Cuntrol Croup* 3is*d in Animal Quartan and in lh Exoovirt Chimb*.-0
Entym*
Air expotad
Animil room
Qmr.Si;*
QnciM-^gtplUM peitydraiwus* Gfuuc/iion* rtducti**
1Z32 t 1,32*
4.77 * 0.2r
11.OS * 1.78* 5.28 i 0.40*
0Valun an m*inj t 5EM {n m 6).
"Kpt in chambvr 7 H/d, 3 d/wit, lor $ wk; total, 710 h. eNot jipiifieant. rfNgt jJ(nifleant.
Sample Preparation
Liver was excised rapidly and was immediately rinsed in ice-cold 0.15 M KCI with 0.02 M Tris buffer, pH 7.4. A portion of the tissue was homogenized with 9 volumes of the cold KCl-Tris buffer in a PotterElvehjem homogenizer. Each sample was prepared from a single organ and kept at 4*C during preparation. Remaining liver was frozen rapidly and stored at --2Q*C. For assays with frozen tissue, livers from control and experimental rats were frozen in an identical manner for the same length of time.
SubceJIular Fractionation and Biochemical Determination
Homogenate was centrifuged at 600 and S000 X g for 10 min and at 100,000 X for 60 min to obtain the nuclear, mitochondrial, microsomal, and cytosol fractions, respectively, by the differential technique of Schneider and Hogcboom (1950). Centrifugation was at 4C in a Sorvall refrigerated. RC5 supercentrifuge with a fixed angle rotor and a Beckman model L-5 ultracentrifuge with a swinging bucket rotor. Enzyme activities and cytochrome P-450 were determined in the isolated subcelltilar frac tions: cytochrome oxidase in the mitochondrial fraction; NADPHcytochome c reductase, mixed function oxidase, cytochrome P450, and glucose-6-phosphatase in the microsomal fraction; and glutathione reductase and glucose-6-phosphate dehydrogenase in the 100,000 X g supernatant fraction.
Cytochrome P-450, NADPH-cytochrome c reductase, and cytochrome oxidase were determined in fresh samples; all other determinations were in m freshly isolated fractions from frozen tissue.7*Glucose-6-phosphatase was estimated by measuring release of inorganic phosphate (Harper, 1965). Cytochrome P-450 was estimated by the maximum absorption difference between the dithionite-reduced cytochrome and its CO complex (Omura and Sato, 1964). The P-450 concentration was calculated by using 91,000
003114 CMA
1122
J.T. DU ET AL.
M~x cm'* as the extinction coefficient for the increase in peak height between 490 and 450 nm. Cytochrome oxidase was measured as described by Wharton and Tzagoloff {1967), and NADPH-cytochrome c reductase according to Oegroot and Ounn (1964). Mixed function oxidase was determined according to Holtzman et al. (1968) by measuring the hydroxylation of anaiine. Nonprotein sulfhydryi was estimated by the method of Sediak and Lindsay (1968). Rate of oxidation of NADPH by oxidized glutathione was used as a measure of enzymatic activity of glutathione reductase (Carlberg and Mannervik, 1975). Glucose-6phosphate dehydrogenase was measured spectrophotometricaliy, as the rate of NADPH formation (Lohr and Waller, 1965). Assays were conducted under conditions of linearity with respect to both time and protein. Protein content was determined by the method of Lowry et al. (1951). Conventional clinical analyses of serum included aspartate aminotransferase (AST, SGOT), alanine aminotransferase (ALT, SGPT), jilkalinc phosphatase, bilirubin,albumin, cholesterol, and triglyceride, determined by the technicon sequential multiple analyzer computer (SMAC) system.
I
Materials
The NADPH, cytochrome c, and oxidized glutathione were obtained from Sigma Chemical Co., St. Louis, Mo. Anaiine and other chemicals were reagent grade. Double-distilled water was used throughout.
Light and Electron Microscopy
Small strips of liver were removed under ether anesthesia and., immersed immediately in icc-cold 396 glutaraldehyde (pH 7.4). Tissues were sliced into small cubes and fixed for 2 h at 4"C. Subsequently, samples were washed overnight in phosphate buffer and postfixed in 196 osmium tetroxide for 1 h before being dehydrated in ascending alcohol and embedded in Epon. Tissue blocks were polymerized at 60#C for 2 d. Thin sections were cut with a diamond knife and stained with uranyl acetate and lead citrate before examination on a Philips 300 electron microscope. For ultrastructural analysis, control rats and rats exposed for 42 and 137 h to vinyl chloride were reviewed.
For light microscopy, a block of tissue was fixed in buffered formalin and processed routinely for paraffin embedding. Sections 6 pm thick, were stained with hematoxylin and eosin before examination.
RESULTS
The protein contents (milligrams per gram of liver) of the subceiluiar fractions in control and vinyl chloride-exposed groups were the same throughout the exposure; therefore, the enzymatic results were expressed as micromoles converted per minute per milligram of subceiluiar protein.
The statistical analysis (sec below) showed certain significant
%
CMA 003115
IJILCXICc &F'qCT3 CN ?,,vr LIVER
enzymatic differences between the exposed and control groups in glucose6-phosphaiasc, glutathione reductase, and glucose-6-phosphatc dehydro genase.
Glucose-6-phosphatase. No significant differences in glucose-6-phosphatase activity v.-ers detected between the two groups up to 42 h; however, after 71 h, the glucose-6-phosphatase activity was significantly less in the exposed than in the control animals. Figure Iff shows the 25% decrease in mean activity of glucose-6-phosphatasc after 71 h; this activity remained significantly lower up to 137 h. Figure 1 b shows the 95% confidence intervals for D, the mean difference between the exposed group and the control groups, in each experiment.
()
FIGURE 1. (a) Composite cum of (roup means of specific activity of tlucow-S-phpsphjtasc with respect to exposure time; (0) 95% confidence intervals for 0, the mean difference between the exposed and contra! troupe. There Is no sifeiflcent difference between the exposed and control troupe until after 43 h of exposure. After 71 h the mean level of the exposed (roup le sicnifleondy less than that of the control roup.
CMA 003116
t
1124
7 J. T. OU ET AL.
Glutathione Reductase. Figure 2, a and b, illustrates the significant differences ip < 0.05) between the exposed and control groups in all 4 experiments except at 71 h of exposure ip < 0.06). The glutathione reductase level was 2596 greater in exposed than in nonexposed animais up to 71 h and approximately 5096 greater after 84 and 137 h.
Glucose-6-phosphate Dehydrogenase. There was no significant differ ence between exposed and control groups from 14 to 42 h and at 71 and 84 h. However, after 103 and 137 h of exposure there was a statistically
significant difference as shown in Fig. 3, a and b. After about 100 h f exposure, the mean glucose-6-phosphate dehydrogenase level in exposed animais was about twice that in nonexposed animals.
While these differences were occurring, none of the conventional biochemical liver function tests (e.g., serum aminotransferases, alkaline phosphatase) showed any significant change, nor were there any changes in cytochrome oxidase, mixed function oxidase, P-450, or NADPH* cytochrome c reductase.
ixpoeueo *MM* "rX
'MM
(k,.) to)
MV
FIGURE 2. (e) Composes curve of (roup meant of tpecific activity of gfotalhitmo dtue wit*1 mpKt to expowre time; (p) 9S% confidence Interval* for 0, tfle moan difference between tho expoecd and control poop, Tho mean value for the expoeed poop b eignifUantfy greater thao that for the control* throughout the entire experiment |p < 0.0J| except at 71 h of expoeure.
CMA 003117
VI.T.'L CHLCRI-* EFFECTS ZS j.aT t. V_:<
nzs
IipwiiMirt
Eiputw*
(hr*]
W
<
FIGURE 3. {a) Composite curve of group mum of tpaclflc activity of glucoso-d-phosphite drhyOrogtnasa with raspwt lo otposur* time; '(h) 95% confidence Intervals for 0, tho moan difference batwaan tha upoud and control troops. The maan vaiua Tor tho exposed froup is not significantly diffarant front that for tha control group until aftar *4 h of exposure.
The concentration of reduced glutathione in the livers of ' rats
decreased to 5296 of the control value after a single 2-h exposure to
15,000 ppm vinyl chloride (Table 2). However, the reduced glutathione
concentration appeared to be the same or slightly elevated when the rats
underwent multiple exposures. This elevation was not significant at the 5%
level. The vinyl chloride-exposed rats suffered a weight loss of 4-1396 and
the control group gained 2-1096 (Table 3). All rats survived to the
termination of the experiment without noticeable ill effects.
-a*-*""*
**
Statistical Analysis of Results
The 9596 confidence interval for group mean differences in each enzyme study was based on the error mean square from a two-factor analysis of variance with interaction,, the two main effects being exposure time in hours and exposure-nonexposure. This analysis was performed for
CMA 003118
t
t
t
113*
J.T. DU CT AL.
TABLE 2. Effect of Vinyl Chloride Exposure on Concentration of liver Nonprotein Sulfhydryl Compound in Ran
Exporara time <h)
2* 14* 28 42 71 84 103 137
Concentration ratio
(exposed/controt)
0.52 (3|* 1.02 (S) 0.96 (6) 0.82 (6) 1.2! (3) 1.07 (3) 1.49 (6) 1.29 (3)
*Stngla exposure. *Number of animals in control or experimental
(roup is shown in parentheses. cMultiple expowres (4-8 h/d. 4-S d/wit) tar
14-137 h.
TABLE 3. Body Weights of Rats before and after Wy( Chloride Exposure*
Accumulated exposure M 14
28
42
71
84
103
137
Time
Betara After
Betara After ^-n- -
BtfOfV
After
Betara After
Betara After
Before Affter
Before After
Control
442 e 6.2* (3j* 454 e 9J (3)
436 * 9.2 (3) 445112.1 (3)
433 * 5.2 (3) 455 1 6.4 (3)
437.6112^(5) 447119.4 (5)
412.71 7.9 (3) 455.01 6.8 (3)
453 1 12.9 (6) 465 e 16.9 (6)
404.7 a 1.2 (3) 425.0 a 5.2 (3)
Change w 3
41 " 5 2
10 . 3 +4
Vinyl chloride*
exposed
Change *m
4531 1J (3) 421 e4it(3) .
-7
- --* .
450 * 4.3(3)
4ioi ia oy
422.7*9.2 (5) 385.0 * 4.2 (5)
425117.4 (3) 399 1 72 (3)
441.5*6.4(4) 397.0 * 5.7 (6)
415.0* 15.7(3) 394 * 28(3)
-9
-U --4
-to
*4
*Moitiple. exposures to UK vinyl chloride for 14-137 h, 4-S h/d, 4-S d/nk. * Results are expressed as mean * SEM.
* Humber of animrfs Is given in parentheses.
CMA 003119
VINYL CHLORIOS EFFECTS ON RAT UVR
1127
each of the four experiments. Overall significant (p < 0.05) differences between the exposed and control groups are found when the 95% confidence intervals (D values) do not contain aero.
in Fig. Vo-, there is no significant difference (p>0.05) between the 2 groups in experiments A and B because a D value of zero is within these two confidence intervals. However, for experiments C and D, the con fidence intervals do not contain a D value of zero, indicating a significant difference (p<0.05) between the exposed and control groups. When the D value is less than zero (as in Fig. lb), the experimental group is significantly lower than the control throughout the experiment; when the D value is greater than zero (as in Figs. 2 and 3), the experimental group is significantly higher than the control. Further, in experiments C and D of Fig. lb, a single confidence interval is shown even though there are two time periods of exposure each. This results from the nonsignificance of the interaction term in the analysis of variance, meaning that the observed difference at 71 h of exposure is not statistically different from the difference at 103 h. Similar conclusions hold for experiment 0 in Fig. lb. Figure 2b shows 2 confidence intervals for the set of experiments C at 71 and 103 h because the interaction of the time and exposure factors was significant; that is, the difference between the exposed and control groups after 103 h of exposure was significantly greater than the difference after 71 h. This is also reflected by the differences of the mean values at 71 and 103 h as shown in Fig, 2a. For the same reasons, there are also two confidence intervals for the C (71 and 103 h) and D (S4 and 137 h) sets of experiments in Fig. 3b.
Morphological Studies
Morphological light microscopic studies were performed in a blind (coded) and randomized fashion and did not show any evidence of hepatocellular injury or changes usually seen in the latter stages of vinyl chloride exposure.
Besides some variations in glycogen content, no difference in the fine structure of the hepatocytes was observed between controls (Fig. 4) and those exposed to vinyl chloride for 42 h. Dilation of rough endoplasmic reticulum was observed in a small number of hepatocytes after 137 h of vinyl chloride exposure (Fig. 5). Although no noticeable change in the amount of smooth endoplasmic reticulum was associated with this change, a concomitant increase in cytoplasmic density was evident in these ceils. Another type of lesion found in other hepatocytes was characterized by. the presence of small patches of dear spaces, which tended' to -aggregate near the ceil periphery (Fig. 6). Such lesions usually affect the adjacent ceil equally. No other cell type appeared to be affected by vinyl chloride exposure in this study.
CMA 003120
m*
I. T, 00 ET AL.
FIGURE 4. Portion of * hupatocyt* from a control rat. A good complamant of mitochondria and rou|h tndoplwmk raticulum b thown (X 12,000). FIGURE 5. Dilation of RER (arrow*) shown in hcpamcytu 137 h aftar exposure to 13,000 PP vinyl chloride during M ok (X23,000). FIGURE 6. Subptamalcmnuf talons (*) in hepatocyiw 137 It after exposure to 13,000 ppm vinyl chloride during 2-3 wh. Thu' talons an ptnmnt in two sdtwnnt mlis and Ik* dor ipscns mm ip eoatac*(XI%000K '
DISCUSSION Decreased giucose-6-phosphatase activity and increased glucose6-phosphate dehydrogenase and glutathione reductase activity irv rat liver after exposure to vinyl chloride (as in our studies) may be the biochemical alterations indicative of early liver injury, adaptation to increased, detoxi fication activity, or preparation for increased nucleic acid synthesis. These differences were observed before any abnormalities were detectable from conventional liver function tests, such as serum aminotransferases, or from changes in other subccilular organelle markers, such as'mitochondrial cytochrome oxidase activity. In primary hepatocellular cancer (hepatomas), the activity of key enzymes for gluconcogenesis (glucose*6-phosphatase, etc.) decreased with increased rate of tumor growth (Weber, 1974; Weber and Convery, 1966; Weber and Lea, 1967). In contrast, two enzymes for the pentose phosphate pathway, glucosc*6*phosphate dehydrogenase (Sclmcci and
CMA 003121
VINYL CHLORIQc ff CTS ON RaT liV c*
Weber, 1976; '.Veber and Morris, 1953) and transaldolasc (Heinrich ct 3l., 1974) , increased in ail hepatomas. Further, the activity of gluclosc-6phosphatase decreased before and during the development of hepatomas when carcinogens such as nitrosamine and dimcthylaminonzobenzene were fed to rats (Jsok and Teras, 1973; Weber and Gintcro, 1955). Whether our similar findings in this study are indicators of eventual cancer development (angiosarcoma) is not yet known. We used a snorter exposure period in order to identify the biochemical changes that would best reflect the morphological and cellular changes anticipated on the basis of previous human and animal studies. No attempt was made to determine what effects these shorter exposure periods would induce with long-term observation. This is now in progress. However, Maltoni and Lsfs.m.ir.s (1975) showed that of 69 Sprague-Dawiey rats exposed to 10,000 ppm vinyl chloride, 16 (26%) developed Zymbal gland carcinomas after 50 vvk, 5 (8%) developed nephroblastomas after 59 wk, and 9 (15%) developed angiosarcomas after 64 wk.
The vinyl chloride-exposed groups lost weight (4-13%) whereas the control group gained weight (2-10%) during the entire experimental period. However, the differences in the three enzymes cannot be accounted for by lack of dietary food intake in the experimental group, because fasting increases glucose-6-phosphatase (Ashmore et aJ., 1954) and decreases glucose-6-phosphate dehydrogenase (Winberry and Holtcn, 1977), and we found decreased glutathione reductase and reduced glutathione content in fasted animals (unpublished data).
Rats exposed to a high dose (5%) of vinyl chloride (Reynolds et ai., 1975) had decreased mixed function oxidase activity. An in vitro study (Ivanetich et al., 1977) showed that the metabolites of vinyl chloride from the microsomal enzyme system decreased the levels of cytochrome P-450. In our studies; the cytochrome P-450 content and the activity of mixed function oxidase and NADPH-cytochrome c reductase in rats repeatedly exposed to 1-2% vinyl chloride did not show any such changes* Sub sequent experiments in which rats were exposed to 28,000 ppm vinyl chloride for 70-210 h in 2-6 wk showed a significant decrease of cytochrome P-450 concentration (in preparation). Differences in dose level or experimental design may account. for these variations. Drew et al. (1975) found that the activity of mixed function oxidase depended on the time interval between cessation of exposure to vinyl chloride and sacrifice of animals.
The main detoxification route for vinyl chloride metabolism is thought to be conjugation with glutathione (Johnson, 1967); sulfur-containing urinary metabolites of radioactively labeled vinyl chloride have-been found in rats' urine (Green and Hathway, 1975, 1977; Watanabe et al., 1976b, 1976c).
We found that under the present experimental conditions- the nonprotoin suifhydryi content of liver (glutathione and/or cysteine) tended to
CMA 003122
t
1130
). t. ou rr au.
increase in rats repeatedly exposed to vinyl chloride (Tabled). Although
the difference was not significant in this experiment, subsequent exposure
of rats to 28,000 ppm for 70, 14r and 210 h in 2, 4, an^^fM<Sf to a
significant elevation of the nonprqMfliwipffhydryl conteh#b*4*lfr?|u and
Tamburro, 1978). Watanabe et ai. (1976a) and Johnson (1967) found a
depletion of nonprotein sulfhydryl content in rats after only a single
exposure to vinyl chloride or chloroethanoi. Hefner et al. (1975) found
that a single vinyl chloride exposure reduced the glutathione content by
one-half, but the decrease became smaller and even unnoticeable after
repeated exposure to vinyl chloride. Fiala et al. (1976) showed that the
reduced glutathione content increased after prolonged exposure of rats to
various chemical carcinogens. These results are thought to reflect the
exposed animals' attempt to make more glutathione to meet the unusually
strong demand for detoxification.
Glutathione reductase was elevated in our system after rats were
exposed to vinyl chloride for 42 h. This enzyme generates reduced
glutathione from its oxidized form as a compensatory mechanism to
maintain the level of glutathione^ and the simultaneous elevation of
gJucose-6-phosphate dehydrogenase regenerates NADPH, which can be used
as a cofactor for various synthetic pathways including nucleic acid
synthesis. Elevated glutathione reductase aciMtf * Was fbuncTfa r^ts- with
primary hepatocellular cancer induced by
4hd :
Bartley, 1973). This consistent increase io gri^iy^
activity
after exposure to vinyl chloride suggests tbatitmay. b*.-one-of
biochemical manifestations of exposuWi iftj&ry. ^ *
These metabolic changes could also play a role in the early changes
observed by light and electron microscopy. HepAttg
jgftiifjpn
of smooth endoplasmic reticulum and loss of
in
mice as early as 1 mo after vinyl chloride exd<Kb9% ^^f)^pf efjrt.,
1976).. In contrast, we observed dHatiors-9^|4ii^ir^iBiilit*piijip|Hil9<,^M^tod6Mrn -
and patchy, lesions near the plasmaiemma. Th*
reticulum could be related to the increased enzyme syn
6-phosphate dehydrogenase and glutathione reductase) induced-Sy ~viii|rt '
chloride. The absence of smooth endoplasmic reticulum proliferation in :
our animals suggests a comparatively milder effect in our short-term study.
In a subsequent study where long-term effects of vinyl chloride exposure
was assessed, dilation of smooth endoplasmic reticulum in hepatocytcs was
observed (in preparation). The nature of the patchy lesions found near the
plasmaiemma remains to be established. The location of the lesion,
however, suggests that some toxic agents may be entering or exiting the
hepatocytcs in these sites.
We believe these early enzymatic changes reflect adaptation of the liver
cell to early mild injury. The alterations in gfuconeogencsis and in the
pentose phosphate shunt appear to indicate the liver's adaptation while
undergoing repetitive and prolonged exposure to the mildly toxic chemical
CMA 003123
VINYL CHLORIDE EFFECTS ON RAT LIVE-'.
. ns;
vinyl chloride, which, when inadequately metabolized, produces inter* mediates that lead to the formation of cancer.
REFERENCES
Ashmore, Hastings, A. 8., and Neibett, F. B. 1934. The effect of diabetes and fasting on <1vr giucose-6-phosphatase. Free. Natl, Acad. Sei. U.S.A. 40:673*678.
Bolt, H. M., Kaopui, H., Such ter, A., and Solt, V/. 1373. Metabolism of vinyl chloride. Lancet
1:1425. Carlber-, I. and Mm-rrvii;, 3. 1375. ?u.*ifi:s::on and ch:r;c:s.*:ia;isn of th: "ivctmyme
glutathione reductase from rat liver. /. 5/eA Cn.fr. 250:5473-3410. Creech, J, U and Johnson, M. N. 1974. Angiosarcoma of liver in the manufacture of polyvinyl
chloride./. Occap. Mtd. 16:150-151. Oe|root, L. |. and Ounn, A. 0. 1964. Electron-tranioort enzymes of calf thyroid. Biachlm.
Btophys. Acta 92:205-222. Drew, R. T., Harper, C., Gupta, B. N., and Talley, F. A. 1975. Effects of vinyl chloride exposures
to rats pretreated with phenobarbital. Environ. Health ferspect. 11:235-242. Du, J. T. and Tamburro, C H. 1976, Decreased ilucose-6-phosphatase activity in liver In vinyl
chloride exposed rats. Fed. Proc. 35:329. Du, J. T. and Tamburro, C H. 1978. Elevated glutathione content, glutathione-5-transferase and
glutathione reductase in liver of rats exposed to vinyl chloride. Fad. Pnc. 37:1545. Flala, Mohlndru, A., Kettering, W. G, Flala, A. E., and Morris, H. F. 1976. Glutathione and
lamma glutamyl transpeptidase in rat liver during chemical carcinogenesis. /. Had. Cancer Inst. 57:591-598. Green, T. and Hathway, 0, E. 1975. The biological fate in rats of vinyl chloride In relation to Its oncofeniclty. Orem. Slot. Interact. 11:545-562. Green, T. and Hathway, D. E. 1977. The chemistry and biogenesis of S-containing metabolites of vinyl chloride in rats. Christ. Biol. Interact. 17:137-150. Harper, A. . 1965. Glucose-6-phosphause. In Mathodt of Emymatlc Analysis, td. H. U. Berfmeyer, pp, 788-792. New York: Academic. Hefner, IL Watanabe, P. G., and Gehring, P. J. 1975. Preliminary studies of the fate of Inhaled vinyl chloride monomer In rats. Ann. At.Y. Acad. Sd. 246:135-148. Heinrich, P. C, Morris, H. P., and Weber, G. 1974. increased phosphdribosylpysophosphate synthetase activity in rapidly growing hepatomas. FEBS Lett 42:145-146. Hoitzman, J. L, Gram, T. E., Grpon, P. L., and Gillette, J. R. 1966. The distribution of the components of mixed-function oxidase between- the rough and the smooth endoplasmic reticulum of liver cells. Bfochem. J. 110:407-412. Isok, M. . and Teres, 1_ E. 1973. Glucose-6-phosphatase activity rn liver carcinogenesis and In transplantable hepatoma in mice, Vopr. Med. Khim, 19:566-570. 1varieddt, K. M., Aronson, I, and Katz, I. D. 1977. The Interaction of vinyl chloride with ret hepatic microsomal cytochrome P-450 In dm. Bfocltam. Bfophys. flat. Comemae. 74:1411-t41g. Jaeger, R. J, Reynolds, . i, Connolly, R. B., Moslen, M. T., Sxabo, A., and Murphy, S. M. 1974. Acute hepatic injury by vinyl chloride In rats pratraated with phenobarbital. Nature (Land.) 252:724-726. Johnson, M. K. 1967. Metabolism of chloroethanel in the ret. Btaeham. Pharmacol. 16:165-199. Lehr, G. W. and Waller, H. D. 1965, Glucose-6-phosphate dehydrogenase. In Mathodt of Enzymatic Analysis, ad, H. U. Bergmcyar, pp. 744-751. New York: Academic. Lowry, O. H., Rosenbraugh, N. J., Farr, A. L., and Randall, R. ). 1951. Protein measurement with the Foiln phenol reagent. /. Bid. Cram. 193:265-275. Melton!, C and Lefemine, G. 1975. Carcinogenicity bioessays of vinyl chloride: Current results. Ann. At Y. Acad. Sci 246:195-216.
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Omura, T. and Sato, R. 1964. The carbon monoxide-binding pigment of liver microtomes. I. Evidence for Its hemoprotein nature. /. Biol. Cfirm. 239:2370-2378.
flnto, R. E. and Bartley, W. 1973. Glutathione reductase and glutathione peroxidase activities in hepatomou* liven of rats treated with diethyl nitroumine. FEES Lett. 33:307-309.
Reynolds, E. S, Moslen, M. T., Szabo, S., and iaeter, R. J. 1975. Vinyl chloride-induced deactivation of cytochrome P-450 and other components of the liver mixed function oxidase system: An in Wvo study, to Common. Chem. Pathol. Pharmacol. 12:685-694.
Schaffner, F., Popper, H., and Selikoff, I. J. 1976. Initial features of vinyl chloride hepatic Injury. Gattroantarology 71 :A35 (abstr.).
Schneider, W. C. and Hopeboom, G. H. 1950. Intracellular distribution of enzymes. V. Further studies on the distribution of cytochrome t in rat liver homo^nates. J. Biol. Cham. 183:123-123.
Sedlak, J. and Lindsay, R. H. 1968. Estimation of total protein bound and non-protein sulfhydryl (roups in tissue with EllmanS reagent. Anal, Bioehtm. 25:192-305.
Seimed, L. E. and Weber, G. 1976. increased (lucose-6-phosphate dehydrogenase concentration in hepatoma 3924A: Enzymic and immunolo(lcal evidence. FEBS Lttt. 61:63-67.
Tamburro, C. H, Makk, L, and Popper, H. 1979. Early hepatic histological alterations among chemical (vinyl monomer) workers. Gastrotnurology, in prase.
Viola, P. I_ Bijotd, A, and Caputo, A. 1971. Oncogenic response of ret skin, lungs; and bones to vinyl chloride. Cancar Has. 31:516-522.
Watenabe, P. Q., Hefner, R. E., Jr, and Gehring, P. ). 1976a. Vinyl chloride induced depression of hepatic non-protein sulfhydryl content and effects on bromosulphaloin (BSP) clearance la rata.. Toxicology 6:1-8.
Waunabe, P. G, McGowan, G. R, and Gehring. P. M. 1976b. Fata of '*C-vtoyl chloride after single oral administration in rats. Toxicol,- Appl, Pharmacol. 36:339-352.
Watanabe, P. G, McGowan, G. R., Madrid, E. O, and Gehring; P. J. 1976c. Few of l4C-ytnyl chloride foilowing inhalation exposure in rets. Toxicol. Appl. Pharmacol. 37:49-50.
Weber, G. 1974. the molecular correlation concept, to The Motaariar Btoioay of Cancar, ad. H. Busch, pp. 4(7-571. New York: Academic.
Weber, G. and Cantero, A. 1955. Giucose-6-phosphause activity in normal, ptocanceraus, and' neoplastic tissues. Cancar Res. 15:105-108.
Weber, G. end Convery, H. J. H. 1966. Insulin: inducer of ghKose-6-pfmphaCe dehydragpoaee. Ufa Sci, 5:1139-1146.
Weber, G. end Lee, M, A. 1967. The moleculir correlation concept. In Mathodb ht Cancar Research, rd. H. 8usch, vol. 2, pp. 523-578. New .York: Academic.
Weber, G, and Monte, H. P. 1963. Comparative biochemistry of hepatomas. Ilf. Carbohydrate enzymes In liver tumors of different growth rates. Cancar Bat. 23:987-994.
Wharton, o. C and Tzagoloff, A. 1967. Cytochrome oxidase from beef hoert mitochondria. In
Methods ht Entymatogy, eda. R. W. Estabrook and M. E. Pullmen, tel 10, pp. 245-250. Now York: Academic. - Wleheny, L. end Hoican. O. 1977. Rat liver giucose-6-phoapham tdlydispnue. Oietary ngulatian of dm ram of synthesis. /. BM. Cham. 252:7796-7801.
Bacafrad March 30, 1979 Artaptad July 23, 1979
CMA 003i25
3
THE YALB JOUBNAL Of BIOLOGY AND MEDICINE 51 (1978), 67-80
The Hepatic Role in Carcinogenesis and
Its Early Detection--The Vinyl Chloride Model1-2
CARLO H. TAMBURRO University of Louisville School of Medicine, Louisville, Kentucky
Rc*i*vd Oclnhsr 17, 1977
Th liver's rah ia vinyl chloride tonicity sad carvuNxeaicity h pravidht a betterimdemnedinB atthe chemical esicioopwiMti mechatism. A vwtey at both mslipasra end beeto hepatic Brawn has beep demonstrated with pmioeped enpoeuiv to vinyl chloride. The muitj^ysteei wvoivmni atthis csirinopui sad tonin has pravidad a owdel (brthe study ofchemical caraaoprawsis eeraaran to both nan end aniraal.
dewcDon of tonic end ceicioopeoic lesions. Aaiaral undies have dsawpawl the biochsinicsl raetsb olisra by the liver ofvinyichloride-pradMced irasrnndlsm which see snpsBseh in bncwrieliiiitimi Md may be the uttimau onanopsns. Hepatic mbrsiiuier wrayrae imdira pnive pnriimiwry nidwirs of
may be the key to the eisli^snl tnmhnaation at cans. A woriuae hypothesis is prassraed which may
espiera the rasnheliira of vinyi chloride into pppsbiipc jnsswnsdistes by the liver ce sad the develop-
mens of hjaseattrensfonpatwa by astro hipetlr tinuenidai liniep reds, hrapredi. end brain thsue.
INTRODUCTION
Currently there is a growing concern that chemical compounds may be respon sible for most human cancer through environmental contact. Although 100,000 to 200,000newchemicals are introduced into industryeach year, little is knownabout their effects. These compounds are primarily synthetics and thus not natural to the environment The view that industrial chemicals may be latent carcinogenic hazards has again been brought into sharp focus by the discovery ofvinyl chlorideinduced angiosarcoma. Vinyl chloride (CHi - CH-Cl monochloroethyene, a gas} is the basic molecule or monomer ofpolyvinylchloride and its co-polymers and one of the most important organic intermediates in the plastics industry. The resulting plastic resin, polyvinyl chloride, is used.in innumerable consumerand industrial products, such as containers, wrapping Bn*, electrical insulation, pipelines, credit cards, etc. Until recently (early 1970's) vin'ylchloride was regarded as being rela tively noo-toxk[ 1,2]. Initially this opinioa seemed to be supported by the facts that it was used transiently as an anaesthetic and had been used commercially in indus try for many yean [3].
The direct information on the toxicity ofvinyl chloride to man was obtained from experiments by research workers on themselves, from the evaluation of its suit-
67
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CMA 003126
68 carlo h. TAMBURRO
ability as an anaesthetic [4,5], and from study of the cases of vinyl chloride poison ing contracted during industrial use (6, 7, 8, 9].
Sporadic studies with vinyl chloride polymerization workers demonstrated vary ing degrees of hepatic biochemical derangements, hematological abnormalities, and skin changes (9). Acute short term exposures led to disturbances ofthe central nervous system, cardiac anythmias, severe irritation of the mucosal membrane of the eyes and the respiratory tract, and in some cases--severe pulmonary edema with obstruction of the liver and kidneys. Chronic inhalation trials in animals clearly showed that vinyl chloride was toxic to the liverand kidneys as well as irrita ting to the mucosal membranes and the lungs. Microscopic examination of liver sections showed degeneration of the central lobules while the damage to the kidneys chiefly involved the tubule and the interstitial lining somewhat like that of carbon tetrachloride damage [10, 11,12].
BACKGROUND
The literature, however, contained virtually no information on damage to man after chronic exposure until Filatova et al. reported disturbances of the blood vessels and nerves in individuate exposed with 20-300 ppm of vinyl chloride on a continuous basis [13]. Cordier ct al. [ 14] and Wilson etaL [15] were the first to re port the hitherto unrecognized disorder termed occupational acroosteolyste (AOL) which included the symptoms oftenderness ofthe fingertips, gradual destruction of bony integrity of the fingers and a Raynaud's-like phenomena.
Studies were initialed inanimate to reproduce the acroosteolysis. In 1971, Violi et al. [ 16] while exposing animals to 30,000 ppm to induce acroosteotysis, accidentally discovered cancer. Maltoni et aL [17] while studying various levels of exposure demonstrated that angiosarcoma occured at 250 ppm; the Manufacturing Chemists Association's studies [18] demonstrated these liver cancers even at 50 ppm. At the same time, Dr. John Creech, at the B.F. Goodrich Chemical Company Plant in Louisville, Kentucky, discovered an hepatic angiosarcoma in one employee. Creech, recalling anearlierhepatic angiosarcomaat the plant, reviewed the medical histories of previous employees. Four additional angiosarcomas were found, further supporting the connection between vinyl chloride exposure and tumor development. Measures to control the levels ofvinyl chloride exposure were then instituted following federal regulation.
THE CHEMICAL
Vinyl chloride's chemical structure is a double-bonded, 2-carbon halogenated hydrocarbon which has structural similarities to tri-chloroethylene, an inhalation anaesthetic. As previously noted, vinyl chloride was once considered as an anaesthetic but was discarded because it caused myocardial irritability. Someofits important physical properties include a low boiling point, a high specific gravity, a km solubility in water, and a half-life in air which ranges from 3-20 hours. Knowledge ofthese physical properties may be important in determining how this agent produces a cumulative effect in the environment which ultimately leads to cancer formation.
Vinyl chloride is both toxic and carcinogenic, as recognized by the wide variety of associated disorders which have been found among vinyl chloride polymeri zation workers and vinyl chloride-exposed animals. A yet incomplete list of these
CMA 003127
VINYL CHLORIDE--RELATED CARCINOGENESIS
Table i Occupational Vinyl Chloride Exposure Associated Disorders
2. Rmrulocytom J. Sptenonwtaly 4. Hepatic fibroxu J Scleredvine-Jike skin chwigti 4. Acro-oMeotyj 7. Raynaud't phenomenon
10. Pulmonary (uoctnsMl impaumetu 11. Aaaxnarcoma 12. Caidiac anhythmia 13. NephroMaitomu* U. Zymcai jiand cucuionus* 13. Lartc cell lung caocxr 14. Brain cancer
In rata only
69
associated disorders is shown in Table 1. Animal and epidemiological studies indicate the probability that cancerinduction at other sites is also directly attributed to prolonged and excessive vinyl chloride exposure [19].
In order to develop effective methods of prevention, accurate knowledge of the pathogenesis of this environmental chemical in ultimately producing its most destructive effect--cancer--is needed.
EXPERIMENTAL ANIMAL STUDIES--TUMOR FORMATION
The carcinogenicity of vinyl chloride has been demonstrated in a variety of animals as well as in humans at exposure levels that vary from 50-30,000 ppm. As illustrated in Table 2, a variety of tumor types have been found in rats, mice, and hamsters. An extensive list ofbenign tumors have also been reported in mice, rats, and hamsters exposed to vinyl chloride. Maltoni's group has now demonstrated primary liver ceil cancers in exposed newborn rats.
Direct hepatocellular injury as well as pulmonary, mucosal and skin injuries have been shown in directly exposed animals. Pretreatment with many agents increases the toxicity ofvinyl chloride; they include phenobarbital, ethanol, polychlorinated biphenyls and pesticides such as hexachlorobeazene [20]. This relationship to vinyl chloride's ability to induce cancer is under study, particularly in view of the industrial environment which allows exposure to many chemicals to occur con currently.
HUMAN STUDIES
Epidemiological studies in the human strongly suggest that exposure beyond 10 yean is associated with increased cancer mortality, mainly digestive system cancers, primarily hepatic [21,22]. There also appears to be a higher incidence of large cell carcinomas of the lung, brain glioblastoma multiforms, and lymphomas [23,24], although there is some disagreement as to the interpretation of this aspect of the epidemiological data.
CMA 0312Q
70 CARLO H. TAMBURRO
TABLE 2 Carcinottoicity of Vinyl Chloride
(Exposure: JO-10,000 ppm)
Tumor Type
Species
1. Liver--Mpoeareoam 2. Liver- lapalncillular carcinome 3. Luoj adenocarcinoma 4. Lima--larprceflcvctnoao* 3. Mammary adenocarcinoma 6. Zymbalgiandtumors 7. Nephroblastoma *. Omochoodromns 9. Skk epitheliomas 10. MeUaomas II. GUoMaattma multifonne 12. Lymphoma
Adult humaai, rata, aanir"------i Newborn m* Pan end mice Humana'
Mice Rail PU Ran Hamaten Hamsun Humana* Humana*
Sw#y ituprterl rpirtemiolopinPy
The multisystem involvement of this carcinogenic and toxic chemical is ftirther illustrated in man. Early physical findings of vinyl chloride-injury include hepato megaly, portal hypertension, possible mild systemic pulmonary hypertension, bilateral midzonal pleural thickening of the lung, and splenomegaly with and without increased portal pressure [25]. These anatomical and physiological findings most frequently occur in the absence of the traditional clinical biochemical derangement of the liver. Screening studies of vinyl chloride workers during the past two and a half years have clearly illustrated the irregular and often delayed appearance ofabnormalities in aspartate and alanine aminotransferases (SGOTand
SGPT), alkaline phosphatase as well as other hepatocellular enzymes. Gamma glutamic transpeptidase (GGTP), believed to be a more sensitive indicator of hepatocellular injury, has proven to have too high afalse-positive rate to warrant its
use in the screens for hepatocellular injury. Sorbitol dehydrogenase (SDH) studies "utif"** that this enzyme, which is liver tissue specific, is too insensitive for primary screening but is useful for confirmatory testing.
Anionic dye clearance studies (Indocyanine Green, ICG) have demonstrated the highest specificity and sensitivity of all the primary screening procedures tested when performed at the 5 mg/kg dose level. At the traditional 0.5 mg/kg level, it has the same effectiveness as the aminotransferases and alkaline phosphatase com bined. The frequency of abnormal ICG dye clearances increases with prolonged exposure to vinyl chloride as illustrated in Fig. 1 and correlates well with the cumulative exposure to vinyl chloride as well as the histological evidence of hepatocellular injury. These functional studies for detecting hepatocellular injury do not, however, identify the cause.
nimpal studies have illustrated the usefulness ofradioisotopic liver-spleen scans as a primary screening procedure for anatomical lesions of the liver and spleen. This procedure has proven to be the single most reliable method oftumor detection. Sixteen ofthe 19 individuals with anatomical lesions were detected by liver-spleen scan. In contrast, only 32 of 930 normal individuals had scan abnormalities which further diagnostic studies proved incorrect. This method provides an 84% sensitiv ity and 97% specificity, with only a 3% false-positive rate.
CMA 003X29
V,m,E>'ESl$
Diagnostic angiographic studies of these rauioisotopic abnormal!cies in 30 individuals have demonstrated 5 major lesions. The first is peliosis hepaiis, illustrated in Fig. 2. These lesions are usually numerous involving the entire liver, and have a diffuse stain throughout the nodules which persists into the late venous phase without central hypovasculahty [26].
A second, similar lesion has been discovered in individuals with splenomegaly, and named lienai peliosis (Fig. 3). These splenic lesions demonstrate a shortened celiac artery to portal vein circulation time, normal portal vein diameters, and increased spleen size. This has been found only in individuals with long-term vinyl chloride exposure.
The final lesion is that of angiosarcoma (Fig. 4). This tumor has characteristic angiographic features of central hypovasculahty, midanerial puddling, and a prolonged peripheral tumor stain which continues up to 30-36 seconds after injection. These characteristic findings have allowed differentiation from otner primary hepatocellular cancers, benign tumors and benign vascular lesions [26], These angiographic lesions have been pathologically confirmed with the additional histological finding including peliosis hepaiis, sinusoidal dilatation, and activated sinusoidal cells with increased deposits ofcollagen in the sinusoidal space ofDisse. Exploratory wedge biopsies have in addition demonstrated increased subcapsular fibrosis with subcapsular bile duct proliferation plus the often described portal
fibrosis [27]. VINYL CHLORIDE METABOLISM AND CARCINOGENESIS
Present biochemical knowledge indicates that vinyl chloride is most likely metabolized by the liver in a three step process [28]. At concentrations less than 30 ppm, vinyl chloride is metabolized by the alcoholic dehydrogenase system into chloroacetaldehyde and monochJoroacetic acid.
CI-CH-CHi--O-CHj-CHj-OH ----- TM --.CI-CHi-CHO--^hCHi-COOH dehydrogenase
An alternative pathway which appears to become operative at 220 ppm is oxidation by the peroxidase-catalase system.
Qtljyci
n M*l/W n % % V.
no. 1. FnquMCy Of
aoei vteyl ddorid* wwfes wtiii-
tiaeOJ MdkeaadS.Ompkedmst.
CMA 003130
72 CARLO H. TAMBURRO
4
F1Q. 1. Spttakartariocram: Vnow ptaw (15 immM. Hi** am 1-4 rirrnlnr and oval itaiia <*
lateral portions of rharpWvn. Nor mal pancraatk main w ifaim inlanic vain.
/
CMA 003131
V
VINYL CKLGKL
RL.-^TiD CaCIN00EN S5 IS
In this ** chloroacetaidehyde is again formed. At higher levels oxidation appears to be by the mixed function oxidase system, forming chloroethylene oxide which spontaneously rearranges to form chloroacetaidehyde which then can be Anther oxidized to form monochtoroacetk acid.
Q-CH-CHi oxidase CL-CH
hO-CHj-CHO--*CICH-COOH
As illastnied in Table 3, vinyl chloride oxidation intermediates chloroethanol and chioroacetaidefayde, at low doses, are most likely detoxified via the glutathi one-cysteine conjugation system. This system, however, is saturable and at higher levels vinyl chloride is excreted via the lungs [28]. It appears that at higher vinyl chloride levels increased amounts of chloroethanol and chloroacetaidehyde are Anther oxidized to chloroacetic acid which is excreted in the urine. This is Anther supported by the absence ofchloroacetic acid in urines ofrats exposed to low, short term levels of vinyl chloride but found in urine of rats exposed to 5,000 ppm for an
rime and reported in workers exposed to levels greater than 250 ppm for a
prolonged time [29, 30], Elmore et al., utilising a modified Ames system and pure synthesized vinyl
chloride intermediates, has demonstrated that vinyl chloride, chloroethanol, and
CMA 003132
7
74
Cl CH - CHi (VC) Liver MFO
rQCH; O
(QUorooxinm)
CARLO H. TAMBURNd
TABLE} Prepaid Metabolic Fata at Vinyl CMorfdt
nHwjflfarioa with gfatathiona
a CHi CH) OH
(CMwoMhanoO
OCHtCHO---------(ChionMeataidabyda)
acHiCooH
(Cbioroacatic acid)
I
Iwn p*y-*OHN-
chtoroacetic acid are not mutagenic in bacteriological systems [31]. This may indicate that the vinyl chloride monomer is neither hepatotoxic nor carcinogenic until it has been metabolized to its intermediate forms by the liver and/or other tissues.
Alternatively, chloroethanol--the most transportable of the vinyl chloride metabolites--may be transferred or diffused to adjacent ceils, such as the sinusoi dal lining cells, where it could be converted to chkxoacetaldehyde but less likely to be detoxified or further oxidized. Since vinyl chloride appears to bind the serum albumin, it may, itselfbe transported to and oxidized by extra-hepatic cells which are unable to fUUy oxidize or completely detoxify its metabolites, and thereby lead to molecular DNA injury and cancer formation at distant tissue sites.
These quandaries led to further study of the hepatochemical changes in rats undergoing progressively increased exposure to vinyl chloride. Subcellular en
zymes and metabolites were studied in animals exposed to from 10-20,000 ppm vinyl chloride, ranging from 14-137 hours. Microsomal enzymes, including P-450,
NADPH cytochrome c reductase, and mixed function pxidaser'were studied. Determinations of cytochrome c oxidase as the mitochondrial, tritiated4eutine
incorporation as the protein synthesis and glucose-6-phosphataae as die carbo hydrate metabolism markers were also done. Glutathione and glutathione reduc tase as oxidative and detoxification markers were determined in addition to the conventional clinical biochemical studies which included the aspartate (SGOT) and aianlno aminotransferase (SGPT), alkaline phosphatase, bilirubin, lactic acid
dehydrogenase (LDH), total protein, albumin, cholesterol, and triglycerides. During the entire 137 hours ofexposure there were no significant changes in the
mitochondrial and the microsomal enzymes, the tritiated4eudae incorporation, or
in the glutathione content. There was however, after 71 hours, a rise in the gluta thione reductase and a concomitant fall in glucosc-6-phosphate. This occurred without any histologically discernible changes in the hepatoeytes by light micro scopy nor any significant changes in the conventional clinical biochemical studies.
/
CMA 003133
;r.i ciicover/ Oi auecrcuis:.
'.JSji'...:_ji _;;r
c..rcr-ic
expoaiire ;sc ;o :r.; s:-uy v: er.z;.'m;s m ;r.s pez,.,i_* z.-.^zr--.s jr.zr.; p^;z.',ay.
Weber and Lea [32] had found similar changes for primary hepatocellular neo
plasms, demonstrating that in a rapidly developing primary hepatocellular tumor,
there is decreased giuconeogenesis with a reduction in the glucose-6-phosphatase,
followed by an increase in slucose-6-phcsphate dehydrogenase and transaldolase.
These biocnemicai changes were also followed oy an increase in purine biosynthe
sis (increased phosphoribosylpyrophosphate aminotransferase fFRPP) and in
creases in the production cf ATP and GTP leading to increased nucleic acid
synthesis.
Vinyl chloride-exposed animals showed no significant changes in the glucose-6-
phosphatase dehydrogenase activity during the initial 84 hours of exposure.
However, after 103 hours, there was significant increase in gluccse-6-phosphatase
dehydrogenase. Studies of ?RPP, at least up to 127 hours, have as ye: shown no
significant changes. Studies are now underway using animals exposed to 130 to 220
hours to determine if the biochemistry in vinyl chloride injury is similar to that in
primary hepatocellular tumors.
This, however, does not explain why the hepatocyte, which is the primary cell for
oxidizing and detoxifying vinyl chloride, is not the primary target for cancer trans
formation. How do the hepatocytic biochemical changes, seen in the early phase of
high vinyl chloride exposure, relate to the later morphological changes that occur in
the adjacent sinusoidal cells?
MORPHOLOGICAL FINDINGS
Electron microscopic examination of liver sections of mice exposed from 1 to 6 months to 2.200-6,000 ppm vinyl chloride, for 5 hours/day, 5 days/week--a level known to induce angiosarcoma (33]--have demonstrated hepatocellular changes as early as one month. These changes included hypertrophy of the smooth endo plasmic reticulum (believed to reflect vinyl chloride metabolism) and, plasma membrane loss of microvilli with invaginations--possibly reflecting the movement of injurious metabolites across the membrane and out of the cell, allowing the metabolites to be picked up by the sinusoidal cells [34],
The cell reactions were multicellular. Increasing numbers and sizes of lipocytes were seen with little fibrosis. Macrophages were seen filled with phago somes, sometimes containing long needle-like crystals. Although there were many mononuclear e*n present, the main abnormalities were seen in the endothelial lining ceils. In the early stages they are larger and thicker--possibly swollen. Later,
they became bulky and in places, multi-layered containing increased organelles, especially mitochondria and endoplasmic reticulum. Later disruptions in the sinu soidal walls seen were consistent with beginning peliosis hepatis. The lining cells, probably the precursors of angiosarcoma, often resembled fibroblasts. However, their endoplasmic reticulum did not contain any collagen components. These observations by Schaffiier et al. [34] give support to the suggestion that metabolites of vinyl chloride produced in the hepatocytes may be transported .through the plasma membrane and enter sinusoidal lining cells, eventually leading to angio sarcoma. Attempts at screening for vinyl chloride hepatic injury might be better aimed at the endothelial cells and the hepatic sinusoidal circulation rather than the
hepatocytes. Our work in humans has identified similar findings. One major difference at
CMA 003134
76 CARLO H. TAMBURRO present is an increased collagen deposition, characteristic ofhuman vinyl chloride injury and likely species specific. Light microscopic studies utilizing special stains on hepatic tissue from individuals with extensive exposure to vinyl chloride but without clinical biochemical hepatic abnormalities have shown distinctive midzonal increased deposition of collagen in the space of Disse [35]. Routine light microscopic studies using hematoxylin and eosin foiled to easily demonstrate this midzonal increased collagen. The increased deposition along the hepatic ceil surface is associated with larger sinusoidal space and activation of the sinusoidal lining cells illustrated by increased nuclear size and cytoplasmic content The in creased collagen deposition, when studied electron microscopically, demonstrates compression ofthe hepatocytes by the collagen bundles which initially give the ap pearance of fomt-hepatocellular collagen bundles as illustrated in Fig. 5. The strands of collagen appear to compress the hepatocytes causing cords of hepato cytes to be broken and to coalesce with adjoining sinusoids eventually leading to peliosis hepads-like lesions.
These observations led us to the study ofthe pioteroglycan role in collagen form ation in vinyl chloride-exposed workers. It had been suggested in the literature that glycosaminoglycans in blood and/or urine might be useful as means ofearly cancer detection since a number of studies had demonstrated the production of sul&ted glycosaminoglycans with malignant states. Pathologists have often used this feature as a diagnostic aid in characterizing malignant vascular turnon of the skin
CMA 003135
'l
vinyl c:n.c2izz--carcinogenesis
[36], Cihirs have noted a strong positive Alcinn blue glycosaminogiycan staining
reaction in human angiosarcoma tissue [371. This suggested that quantitative and
qualitative determinations of glycosaminogiycan production in individuals with
neoplasm, either by serum or urine, might be used to identify those at high risk or as
an early indicator of neoplastic formation. The feasibility of glycosaminogiycan
"spot test" for vinyl chloride production workers made this an attractive possibil
ity for mass screening.
Urinary glycosaminogiycans, measured as uronic acid, were studied in individu
als with alcoholic cirrhosis, viral hepatitis, secondary liver metastasis, hepatic
angiosarcoma and normal controls.
The percentage oftotal glycosaminogiycans that was diaiyzable and the percent
age ofunfracdonaled total that appeared in the hyaluronic acid, chondroitin sulfate,
or in the heparin fractions was similar for all groups. However the distribution of
positive fractions varied with the different groups studied.
Seven of the nine vinyl chloride-exposed individuals, other than those with
angiosarcoma, had glycosaminogiycan positive chondroitin sulfate fractions with
negative hyaluronic add and heparin fractions whereas this occurred in only 3 of
the 32 urines from other hepatic diseases [38].
In addition, study of the total tissue glycosaminogiycan levels in angiosarcoma
tumors and Sbrotic tissue adjacent to the tumor demonstrated that tumor tissue
itself had higher levels ofhyaluronic acid and heparin fractions as compared to the
non-tumor adjacent tissue which had higher levels of chondroitin sulfate fractions.
A n>ilar relationship was found in cirrhotic liver tissue and normal controls. This
data conforms to reports by others that both hepatic connective tissue disorder
[39,40,41,42,43] and hepatic cancer [44] result in increased hepatic glycosamino
giycan levels. It may be significant that the angiosarcoma patient has half the
urinary glycosaminogiycan excretion of patients with liver metastasis and that
analysis ofangiosarcoma tumor tissue exhibits halfthe glycosaminogiycan content
reported by Kojima et al. [44] for hepatocellular carcinoma. The increases in liver
and urinary glycosaminogiycans may well reflect the importance of these substan
ces in the process of fibrogcneaia and tumor growth. Although no significant
differences were found in total glycosaminogiycans of vinyl chloride-exposed indi-
viduals with associated liver injury, there was a significant difference in the excre
tion patterns of these individuals. Seventy-eight percent of them had positive
chondroitin
fractions in contrast to only nine percent of the non-exposed
liver injury cases. Thus the change in the glycosaminogiycan excretion pattern in
individuals with pie-cancerous injuries may be of significant prognostic and
diagnostic importance [43].
The urinary glycosaminogiycan excretion patterns in an angiosarcoma patient 3
months to 2 weeks priorto death demonstrated an increase in the urinary chondroi-
rii| fraction with a change in its composition as the disease progressed.
During this Hma, the chondroitin sulfate composition showed acontinuous increase
in the ratio of the 1.25 M NaCl to the 1J M NaCl fractions. This was due to an
increase in the 1.25 Meluaie and a decrease in the 1.3 M eluate fraction and was 23
times greaterthan the controls. In the most advanced stage ofthe angiosarcoma the
ratio increased to 13.7 times greater [46].
These very preliminary studies would suggest that alterations in the ratios of
these fractions' compositions may be useftii in evaluating the severity and
subsequent progression of disease. Early lesions may produce small changes in the
ratio which would become more pronounced as the disease worsened. The
CMA 003136
78 CARLO H. TAMBURRO
determination ofthis ratio might also be useful in identifying those individuals with significant injury or continuing progression of disease despite changes in the environment. Finally therapeutic measures for intervention might be better evalu ated for their effectiveness in arresting cancer development as reflected by the glycosaminoglycan changes which in turn reflect changes in collagen formation.
SUMMARY AND HYPOTHESIS
Vinyl chloride appears to enter the body through the respiratory tract, the skin, or by swallowing; it is absorbed and transported to the liver by the systemic and portal circulatory systems. In the liver, the primary site of metabolism, it is oxidized by various enzyme systems: alcohol dehydrogenase at lower exposure levels; the peroxidase-catalase system at intermediate levels; and mixed function oxidases at higher levels. At the higher levels, the mixed function oxidase system transforms vinyl chloride to chlorooxiranes which are then spontaneously trans formed into cboroethanol and chloroacetaldehyde.
These two intermediate metabolites, chloroethand and chloroacetaldehyde, are detoxified by conjugation with glutathione and cystdne-SH groups and are excreted m the urine. At even higher doses increasing amounts ofthe chioroacetaldehyde are further oxidized to chloroacetic add and excreted as an end product in the urine. However, when chloroacetaldehyde and/or the chlorooxiranes exceed the detoxification threshold ofthe hepatocyte, this leads to hepatocellular toxicity and/or stimulation ofthe sinusoidal cells. This acute event in turn acts as a stimulating mechanism for increased collagen deposition in the space of Disse and sinusoidal areas as shown by electron and light microscopy studies. The increase in the collagen depostion in sinusoidal spaces then leads to disruption of hepatic cell surface function, disruption of the hepatic cords, coalition ofthe sinusoidal spaces and eventual peUosis hepatis. These lesions alternately lead to sufficient vascular dysfUnctkm to add further to the biochemical manifestation of hepatic cellular injury.
Since it is highly unlikely that the unstable chlorooxiranes are able to be trans ported to adjacent ceils and that the chloroacetaldehyde would most likely be conjugated or detoxified within the hepatocyte, ad intermediate form, such as chloroethanol, which is transportable from the hepatocyte, may then mov*on to the adjacent sinusoidal lining cells, or possibly even further to other extribepatic tissue. At these extrahepafic sites, an intermediate, such as chloroethanol, may then be converted to chloroacetaldehyde. The extrahepafic tissue sites are most likely unable to fiuther convert the chloroacetaldehyde to chloroacetic add nor to detoxify it sufficiently, if at all, by their own detoxificffion systems. This would allow a longer contact period with the cell's DNA. In addjtkm many ofthe extra hepafic cells normally are regenerating at faster tales than hepatocytes, thus increasing the possibility of DNA derangement and ultimata carcinogenesis.
Alternatively, vinyl chloride itself may be taken up by extrahepafic tissue, oxidized but incompletely detoxified, allowing the cell itselfto become susceptible to direct DNA injury. In this or similar manner, chemical-metabolites may induce injury to the DNA in rapidly replicating cells at sites beyond the liver, thus accounting for other cancers developing with vinyl chloride.
The recent work by MaHoni's group, showing that exposure of newborn rats to the same dose of vinyl chloride as adult rats, results in primary hepatocellular carcinoma (40-45%) rather than in angiosarcoma (8-12%), lends further support to
CMA 003137
VINYL CHLORIDE--RELATED CARCINOGENESIS
*9
the concept Lint uie ncputocyie 5
lo resisc v^ncor cnniionn--,ion is
dependent upon its ability to detoxify the mutagenic/carcinogenic metabolite of
vinyl chloride.
This review of our present knowledge of vinyl chloride injury and cancer
formation in man is, at best, a very rough hypothetical outline. With continued
investigation and study it will allow us to more accurately and completely fill in the
missing pieces of this fascinating puzzle, thus leading us to a better understanding of
the pathogenesis of chemically induced cancer in the biologically complex human
system.
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1. Elkin HB: The Chemistry of loduatriel Toaicntoty. Second Edition. Now York. New Yorfc.Joha Wifcy 4 Son
lac. 1910 2. Octtd H; la UUmana's Eazyldopadie dor Tteimtchen Ckotnio. Third Edition. 3:409. Munchea-Bartia. Urban and
Schwarienoots. i)S4.
3. Kunatuntlkocumoo dot Bundouovintihortiauto* : Flames Commute* of the Fodorai Gannon Miiaury of Health), BuAdcignuradhcrlihlaa, J:J*9, 177!
4. vMOtlia|0BWF:ThtHaiaaaaMdAtiphKic,Olcnaic.Cyciic.Araaialk.MdAliNia<ic.Atn<nMicHydrecaiboM htniudiof the Hoinoonotod InMclictiiw Them Tii.ieiiy end Potential fSeiifM iPUC .Mi--yi- iU) m-,*-
ififBn, D.C.. Govonunoat Pnonnj Office, 1935 3. Otter RH, CairCT, KnanJC, eiafc Anesthesia XXVII. Narcosu with vbiyi chloride. 1:339-41, 1947 6. Schawok W: The toaicoy Of vuiyl chloride. Cheat Techn 21:701-711. 1949 7, Gaiivaia S; Vinyl chloride. Free Roy Soc Med, W-275-JI0, 1973
E Brain P, Drachmas. Eds: PuMc-health rounds at the Harvard School of Public Health, viayicdonda: Can the water bo protected? Now Eo( J Med 294:453-457, 197*
9. SeiioffU.Hennood EC, Ede: Toxicity ofvinyl chloride- polyvinyl chloride. Aaa NY Acad Sci 24*: 1-137,1973 10. Irah DO: la Ahpdnsc haioonasad hydrocarbons. Induawal Hypeoe end Toareotoey. Second Ediaoo- Edited by
PA ftty. New York. Inararieaca Pubttahon. 19*3. 2:1241-1332
11. Miniieneiien T Hiker M Hiiinie II ti il Irioe inheletinn -r-rrirr rtf--'nil rhlnrtde in lahnfiiirrr mmli Anar tad Hy* Aiaoc i 21:394-390, 19*0
12. Lener D, Gweubeffi LA. Adatm W1L Elfccte of trifle and repeated exposure* of rianaai and nee ta viayl chloride. Adler lad Hyt Aaeoc J 24:2&S-273. 19*3
13. Pflatova VS. Balakhonov* I, Otaaibeit ES: Hygiene ckaracterisiacs of vinyl chlonde proOutline Gif Tr trot
Zeboi 2:6,1931 14. Conder JM. Flevex C. L4 Fiver.ik Acrwueolys* >t Iobw cmaneei anookes cbez deox oovrietv. affectae
an aetloyeps d'eidnrlewe. Mad Trav 4:ie-i9. 19*6 13. WBioe RH, McConack WF. Tioun CT, ct al: Occupational tcroosteotyvs: Report rill cases. JAMA 201:377-
3*1. 19*7 14. Vioil PL. Dl--w* A. Capeto A: Oaco--ric tesponss of ret aka, map. led bo-- to vinyl chlonde. Cancer Eae
31JIA-J2Z. 1971 17. Marion C. LifieneeGL: Carnreneninty bioeeeeyiorvinyichioride I. Research plan end early lanrie. Envirwo
Ret 70*7-403, 1974
11. Kepda^ ML. Ooode JW. Ootdoo DE. at at Interna malts at sipcwue of no. maters, tad owe to vinyl
cttorMe. Am NY Asm Sd 244:219-224. 1973
19. rniiniraiii --rr iit--nn-irr vj--11
"'-r-r-------------*--- r~`i~-'~T
chtorMri workers. Ann NY And Sd 246:223-230, 1973
20. Star Serin: Soaniflc end wdnriri anaainnn report oo vinyl chloride end polyvnyt chririda EPA*C01A73-
004:44.1973
21. Tr'--lie"**
--**t~^'t~*--"------- **~------- *-------- ---ri--*-------------
chkmde. 1 Oecap Mad Ifc509-51*. 1974
22. Tefrihen fmnrir Aeaodatae lac Stnprimntary epidannriped undy of vinyl chloride workers 1. MsaoT
Own Asaoc 3:1-30, 1973
23. Duck BW. Taylor KJW. WOUena DM: Morality study of workers a polyvinyl cWoride production riant
1 -- ii:1197-99, 1975 24. WxxwriltarlU.Santn'W, Wanner JK. at ah Neoprietri nek anuniwwtanexpoeadnvriyi chloride. Ana NY
Acad Sd 271:40-*, 197*
CWA OO3X^0
80 CARLO H. TAMBURRO
25. Tamburro, CM: Unpublished results 26. Whelan JG, Creech JL. Tamburro CH: Angiographic and radtonuclid* chanctehstscs ofhepabe snpoisrccnw
found in vinyl chloride workers. Radiology 111:549-557, 1976 27. Popper H. Thomas LB: Attentions of liver and spleen among workers exposed to vinyl chloride. Aaa MY Acad
Sei 246:172-193, 1975 25. Hefner RE Jr., Watanatoe PG, Gehring PJ: Preliminary studies of the fsu of inhaled vinyl chloride amaomcr in
rata. Ann NY Acad Sei 246:135-146, 1975 29. Waiaaabe PG, McGowan GR. Gehring PJ: Fate of ,4C- vinyl chloride after single oral adatostrathm in rata.
Toxicol Appl Pharmacol 36:339-352, 1976 30. McGowan GR. Walanabe PG. Gehring PJ: Vinyl chloride urinary metabolites: Isolation and jrlewrifirsbon.
Personal Communication, 1977 31. Elmore ID, Wong JL. Laumbach AD. ct at: Vinyl chloride mutagenicity vie the metabolites cMoraoaimne and
chioncctaldchyde monomer hydrate. Biochim Biophys Acta 442:465-419, 1976 32. Weber G. Lea MA: The molecular correlation concept. In Methods in Cancer Rcacaitft. Edited by NH Baton
NY. Academic Press Inc. 2:523-571. 1967 33. Mahon C. LefemiaeG:Caiinogenicity Mousey* of vinyl chloride: carnet results. Ann NY Acad Sd 246:195--
219, 1975 34. SchaffncrF, Popper H.Selifcofm.et ah Initial features ofvinyl chloride bepetic injury. Oeermemerolntty d:(No.
5) A35/926. 1976 35. Schrodt R. Tamtam CH: Unpublished data 36. Giianl D, Johnston WC. Gtahm JH: Cutaneous angiosarcoma. Caacer 25:166-13. 1970 37. Barr R, Bower M: ' Letters" JAMA 231 (9):9|4, 1975 36. Curran KL. Kupchella CE. Tamburro CH: Urinary glycosaminoglycin patterns in sagunsrrnma ef the liver.
Cancer 40:3050-53. 1977 39. f*he*" JT, Shapira R: Natural history of hepatitis: IV glyconmiiwglyammaat and TUlagin in the htpetir
connective tissue. J Gin loves 52 fill:2952-42, 1973 40. Korxumi T. Nakamura N. Abe H: Changes in acid mucopolysaccharide m the liver in hipster fthmsss Binehhn
Biophys Acta 148:749-56, 1967 41. Kojina J: Studies on the metabolism of hepatic connective tissue in Bbroeis of the Hv. Mad J Osaka Uaiv
16:419-29, 1964 42. Rubin E: Aulotadiotraphic charsctcnzsbon of sulfaced add mueopotyiacdMrida hr experimental drrhaaa. j
Historham Cytochcm 14:666-69. 1966 43. PhtridtRB. Kennedy JS: The syntheds of the tulfated mucopolysaccharides at sites ofhapericftbmms is iadmed
by carbon tetrachloride, amyloidosis, sad the implantation at caipn J Pathol Bacterid 66:549-55, I9M 44. KnJmJ. Kaaatani M. Ohmori K: Tbs glycosanuaogiycaas in human hepatic cancer. Caned Rat 35 (33J42-57,
1975 45. Kupchdta CE, Tamburro CH: Unnery glycosaminoglycan excretion patterns in chemtcahy induced liver tepuy
and caacer. CUn Rat 25:329, 1977 46. KupdsdIaCE,TambMmCH: Urinary and tissue glycosaminogiycan patterns in hepatic sngiosareumi lnPro-
--4t-g- oftha 111 lntiinalinnal Symposium on Detection and PreventionofCaacer. Editedby HE Ntebetgs. NY. Marcel Dekker Inc. 1977
Carlo H. Tamburro, M.D. Cancer Center and Digestive Diseases and Nutrition Division
Department of Medicine University of Louisville School ofMedicine
Louisville, Kentucky 40201
CMh 03139
toxicology and applied pharmacology 62* I-10 (1982)
The Effect of Repeated Vinyl Chloride Exposure on Rat Hepatic Metabolizing Enzymes'
Julie T. Du,: Michael T. Tseng, and Carlo H. Tam burro3
Liver Research Center. Division of Digestive Diseases and Nutrition, Departments of Medicine and Anatomy, and Regionai Cancer Center. University of Louisville School of Medicine. Louisville. Kentucky 40292
Received July 17. 1980; accepted September 12. 1981
The Effect of Repeeted Vinyl Chloride Exposure on Rat Hepatic Metabolizing Enzymes. Du, J. T.. Tseng. M. T.. and Tamburro. C. H. (1982). Toxicol. Appl. Pharmacol. 62, I10. Sprague-Dawiey rats were exposed to 2.8% vinyl chloride lot 2 (70 hr), 4 (140 hr), and 6 (210 hr) weelci to determine the lequential biochemical changet related to the oxidation and detoxification ability of hepatic tissue. Gluuthione-5-tnnsferue(i) activity using 1,2epoxy-fp-nitrophenoxylpropsnc and p-nitrobenzyl chloride as substrates was elevated 17 to 24, 28, and 35 to 42% after 2. 4, and 6 weeks of exposure, respectively, suggesting enzyme!s) induction. Reduced glutathione, the major substrate required to conjugate the toxic metabolites of vinyl chloride, was also consistently elevated. Similarly, the activity of glutathione reductase, the enzyme necessary for the regeneration of reduced glutathione from its oxidized form, was also increased following vinyl chloride exposure. Cytochromes P-450, the major protein in volved with vinyl chloride metabolism, was reduced after vinyl chloride exposure, confirming reports of others that vinyl chloride metabolites destroy P-450. No abnormalities of standard clinical biochemical blood tests of liver function were found during 6 weeks of vinyl chloride exposure. The only consistent ultrastructural modification was the dilation of endoplasmic reticulum. The biochemical and ultrastructural alterations could reflect early hepatocellular adaptation to vtnyl cMonde exposure.
Vinyl chloride, at high concentrations, has been shown to be carcinogenic in both lab oratory animals (Maltoni and Lefemine, 1975; Viola et al., 1971) and man (Creech and Johnson, 1974). Present data support the metabolism of vinyl chloride by hepatic microsomal mixed-function oxidase system into toxic intermediates, chloroethylene ox ide (Bolt et al., 1975; Hefner et al., 1975; Kappuse/ al., 1976) and chloroacetaldehyde
' This work was supported by a grant from the Man ufacturing Chemists Association. Washington. D.C. Portions of this study have been presented (Fed. Proc. 37, 1545, 1978).
1 Present address: Clement Associates, Inc.. 1010 Wisconsin Avenue, N.W., Suite 660. Washington. D.C. 20007.
' Address requests for reprints to: Carlo H. Tam burro. University of Louisville.
(Gross and Freiberg, 1969). These two in termediates are considered to be the ultimate carcinogens (Barbin et al., 1975; Jaeger et al., 1974b; Van Duuren, 1975), to be mu tagenic in bacterial systems (Elmore et al., 1976; Greim et al., 1975; Malaveille et al., 1975; McCann et al., 1975), to act as an alkylating agent by reacting with adenosine (Barbin et al., 1975) and cytidine (Laib and Bolt. 1978), and to bind with protein (Bolt et al., 1976; Kappus et al., 1976; Watanabe et al., 1978). Detoxification of these metab olites occurs mainly by conjugation with glu tathione and is catalyzed by hepatic gluta thione transferases; the conjugates are excreted in the urine as substituted cysteine derivatives (Watanabe et al., 1976b,c; Green and Hathway, 1975, 1977). Chloroacetal dehyde can be further oxidized to chloro-
| 0041-008X/82/010001 -1 OS02.00/0
Copynilii P I SSI by Anew PnB, lac. All nsStl at nwsWKW w Mjl form nunW
CMA 003140
2 DU, TSENG, AND TAMBURRO
acetic acid (Hefner et ai, 1975). These data are compiled id a metabolic scheme in Fig. 1 as an updated hypothesized metabolic fate of vinyl chloride in the adult rat. The me* tabolism of chloroethylene oxide via epoxide hydratase is not listed in the scheme because its product has not been identified.
There have been a few in vivo studies con cerning the effects of vinyl chloride exposure on hepatic concentrations of glutathione (Hefner et aL, 1975; Watanabe et ai, 1976c; Du and Tamburro, 1978), cytochromes P450 (Reynolds et ai., 1975) and on mixedfunction oxidase activity (Drew et ai, 1975; Reynolds et ai., 1975). However, informa tion about the sequential alterations in he patic oxidation and detoxification of vinyl chloride, during prolonged exposure, simu lating the occurrence in workers, is still lack ing. It was reported previously that the en zymatic changes in rat liver following prolonged exposure to vinyl chloride were similar to those found in rat hepatoma (Du and Tamburro, 1976; Du et ai, 1979). The
sequential biochemical changes related to the hepatic oxidation and detoxification of vinyl chloride following prolonged exposure are reported here.
METHODS
Animate and experimental design. Eight- to tenweek-old Sprigue-Dswley male ran (--300 g), sup plied by Laboratory Supply of Indianapoll*. Indiana, were randomized prior to the experiment into three group* a vinyl chlotide-cxpoaad group and the air-cxpoeed group houaad in identical chamber* and a locond control group homed in the University'* Central Animal Care Center. The expaaure level wax 28,000 ppm vinyl chloride, 7 hr/day, 5 day*/week for 2, 4. and 6 wank*. The expoture chamber* were 4400-liter airtight vat*. Vinyl chloride (--300 to 340 g) waa added to the vet to give e time-we^hted avenge concentration at 2S.000 1000 ppm. The chamber air wea changed daily and the vinyl chloride concentration waa determined by gaa chromatography. The air waa constantly circulated by a stirrer. The nti' respirations had negligible effect on the composition of the chamber's aunoapbeie of the chamber'! large volume. Animals were fed on standard laboratory chow pellet* ad libitum.
All animals were tneaihrtiiad with ether, blond was drawn from the inferior yens cava, and the animal* were
(v C) Cl CM 0i2
Cl CHjCHjOH
/
(CHLOaOCTMMMN.)
dctoiimcation with GLUTATHIQHC
(cHLoaaoxiiMM)
Cl 01-0*2
Y S;&mSSlSJy
GS ClIpCM? m*.
tA
N-Ac-S-(2-htdiwxv CTMYL) CYSTIINC
Cl cm2cho
(%) .
GAST
(CHtOnOACCTALDCHYDC)
1
Cl C1I2COOH
GS CH2CH0
GS CHjCOGH
4
THIOOtfiLYCOVIC ACID
(CHLOMACCTIC ACID)
Fig. 1. The proposed metabolic fata of vinyl chloride. (GSH, glutathione; MFO, mixed-function oxidase; VC, vinyl chloride; GEST, glutathione 5-epoxide transferase; and GAST, glutathione 5-al dehyde transferase).
CMA 003141
\ INYL CHLORIDE EFFECT ON ENZY Mts
J
,ii.ia .i^-niimaibiy 20 hr liter e-rvtsure si l *X) pm
sssn 2sv
N \DPH, glutathione. and glutathione disulfiiie were . ctn.ied from Sigma Chemical Company. Si. Louis. Missouri: 1.2-poxy~3-</>-nitrophenoxy)prop>nc *u
purchased from Eastman Kodak Company, Rochester.
New York: p-nurobemyl chlonde was obtained Tram
Matheson, Coleman and Bell. East Rutherford, New Jersey: benzphetamtne was donated by the Upjohn Company, Kalamazoo. Michigan. Double-distilled water
was used throughout.
Sample preparation and biochemical determination.
Homogenates and subcellular fractions were prepared as described previously i Du ti aL, 1979). Each sample
was prepared from a single organ aod kept at 4*C during preparation. The remaining liver was frozen rapidly in liquid nitrogen ind stored at -70*C. Cytochromes P-
0 concentrations were ucterminca in the irozen mi-
orosomai fractions the day following sacrifice. The glu tathione (CSH) concentration, as well as glutathione-
5-transferase, glutathione reductase, and muted-func tion oxidase activities were determined in the freshly fractionated frozen liver. For the assays using frozen tissue, the liven from control and experimental rata were
frozen in an identical manner for the same length of time. Cytochromes P-450 concentration (Omura and
Sato. 1964). nonprotein suifhydryl coolent (Sedlak and Lindsay. 1966). and glutathione reductase activity (Cariberg and Mannervik. 1975) were determined in
the ituczoaomal or cytosol fractions by methods de
scribed previously iDu r aL. 1979).
Glutsthione-5-transferase activity was determined
using the 100,000 X j supernatant fraction. 1.2-Epoxy-
Mp-nitrophenoxy)propnne and p-nitrobenzyl chlonde were the substrates for glutathione-5-epoxide transfer ase and glutathiooe-5-aralkyl innrfertM (GAST), re
spectively. Enzyme activity was determined aa desenbed by others (Habig tt aL, 1974; Kaplowitz tt aL. 1975). All anayi were linear functions of protein eonconiration and timed for at least 2 nun. Solutions of 1.2-epoxy-J(p-nttrophcnoxy)propans aod ^nitrebanzyl cbionda were prepend in absolute ethanol: the final ethanol concsmrauoo in the incubation mixture was 0.5%. Mixed-
function oxidase activity was sstimstad in the micro somal fraction by measuring NADPH disappearance
in the NADPH-dopcndcnt demethyinuon reaction of henTphenminn (La et ai,, 1972). Tim protein content was detenmnad by the method of Lowry tt aL (1951).
The serum dintcai liver tern including aapnrutn ami*
nnmniferma
aminotnnsfaraac, alkaline pboa-
pbntasa, bilirubin. cbolestaroi, and triglyeahde wen detanmnnd by Tachnsoon sequantiai multiple analyzer
cctnpuinr (SMAC) system.
Light and electron microscopy. Smell stripe of liver wen removed under ether snamhama. slioad into small cubes, placed immediately in ice-cold |% osmium tt-
traxide (pH 7.4), and fixed for 2 hr at 4*C. Subse-
uuetttlv samples -*cr* wasitad overnight :n phesphate buffer, dehydrated in ascending alcohol, and embedded in Epon. Tissue blocks were polymerized at 60*C for 2 days. Thin sections were cut with a diamond knife and stained with uranyt acetate and lead citrate before ex amination on a Philips 300 electron microscope. For ultrastructural analysis, three rats randomly selected from controls and groups exposed for 2, 4, and 6 weeks to vinyl chlonde wen studied.
For light micnMcopy, i block of tissue was tixed in buffered formalin and processed routinely for paraffin embedding. Sections 6 aa thick wen stained with he matoxylin and eoatn.
Statistical analysis. Analysis of vanaace was per formed for the various groups at the different time pe riods and multiple comparisons wen performed based on the results of the analysis of variance.
RESULTS
The protein content (mg protein/g liver) in the subcellular fractions in both control and vinyl chloride-exposed groups was the same throughout the exposure (data not shown); the enzymatic results, therefore, are expressed as micromoles of substrate con verted per minute per milligram of protein.
There were no statistical differences be tween the normal and air-exposed groups in the glutathione and cytochromes />-450 con tents or in any of the enzyme activities. The nonprotein suifhydryl content (Table I) was significantly elevated from 26 to 54% at 2, 4, and 6 weeks in the vinyl chloride-exposed group compared to both control groups. Al though the nonprotein suifhydryl content in creased with exposure, the increases were not statistically significant. Glutathione re ductase activity (Table l) in the exposed group was increased by 53 to 77% at all three time periods. The increase in glutathione reductase was the same at 2 and 4 weeks of exposure but showed a further significant increase after 6 weeks of exposure. Glutathione-S-epoxide transferase (GEST, Table l) and glutathione-S-arabcyl transferase (GAST. Table 1) activities were signifi cantly higher than controls after 6 weeks of exposure, 37 and 45%. respectively. The cy tochromes f-450 content, on the other hand.
CMA 003142
TABLE I
Sequential Changes in Hepatic Nonprotein Sulfhydryl, Cytochromes P-450 Content and Activities of Glutathione Reductase and Glutathk>ne-S-Transferases (Epoxide and Aralkyl) in Rats Exposeo to Vinyl Chloride*
Time (weeks)
Treatment 0 2 4 6
DU, TSENG. AND TAMBURRO
Nonprotein sulfhydryi (pmoi/s liver)
Glutathione reductase (100 X pmol/min/mf protein)
GESTO00 x pmol/ min/mg protein)
GAST (10 X pmotf min/mg protein)
Cytochrome P-450 (nmol/g liver)
Normal control Vinyl chloride-exposed Air conlrol
Normal control Vinyl chloride-exposed Air control
Normal conlrol Vinyl chloride-exposed Air control
Normal control Viayl chloride-exposed Air control
Normal control Vinyl chloride-exposed Ait control
7.9 0.3 -- --
5.0 0.2 -- --
9.1 1.6 -- --
2.4 0.4 -- --
17.0 3.7 -- --
7.8 0.4* 9.4 0.2*,t 7.1 0.3'
4.) 0.4* 6.7 0.6*" 4.5 0.2*
7.8 0.4 9.1 1.7 8.1 1.2
2.1 1 0.3 2.6 0 4 2.2 1 0.2
17.1 1.7 13.2 l.l 15.5 1.)
7.1 0.4* 10.2 i 0.6*" 6.9 0.4'
4.2 0.4* 6.3 0.5*" 3.7 0.3'
7.5 1.0 9.7 0.7' 6.3 0.7"
1.9 0.2 2.4 0.3 1.9 0.2
19.7 1.3* 15.3 1.3* 19.6 2.7
6.9 0.4* 11.4 0.6`"
7.9 0.3'
4.8 0.3* 8.9 0.7*"" 5.3 0.4'
7.7 1.0* 11.0 1.3*" 84 0.9"
2.4 0.3* 3.2 0.1*" 2.1 0.2"
IS.S 1.4* 10.6 1.0*" 14.3 1.8'
* Rail were exposed to 28,000 ppm of vinyl chloride; normal coniroll and the air controli were eapoecd to air only. Each number represent! the mean and the SEM from a |>oup of lix rats.
* Normal va vinyl chloride-exposed, p < 0.05. ' Air conlrol vs vinyl chloride-exposed, p < 0.05. ' Vinyl chloride (6 weeks) exposed vs vinyl chloride (2 and 4 weeks) exposed, p < 0.05.
* t 00
w us ic - * -- ..i ^^n...^ts dl
6 'ctx.i ot expcaure .o '-:r.;i ch.crtde iTaoie 1). No differences were found in the hepatic mixed-function oxidase activity or in the serum clinical liver tests. After 2 weeks of exposure, the two control groups had gained wetgnt but the vinyi chtonde-cxpuicd group did not (Table 2). After 4 weeks of exposure, the normal control group housed at the an imal care center had gained significantly more weight than either the air-control or vinyl chloride-exposed group. After 6 weeks of exposure, however, the vinyl chloride-exposea group uued to gain weight; the nor mal control group guinea more than the aircontroi group vlaoie 2).
Morphological examination revealed poly hedral hepatocytes arranged in irregular plates interposed by vascular sinusoids in the livers of the control rats. This gencraJ cytoarchitecture was maintained after vinyl chloride exposure. Hepatocytes in control rats contained a prominent spherical nu cleus, numerous ovoid mitochondria, stacks of rough endoplasmic reticulum (RER), some aggregates of smooth endoplasmic re ticulum (SER), and varying amounts of ly*
icsomes and glycogen particles (Fig. 2a).Few ir.iersuual ceils were scattered among the hepatocytes. These cells contained few cy toplasmic organelles and could be readily discerned at the light microscopic level by their hyperchromatic nuclei. The sinusoids were linked by fenestrated endothelium and some of the lining cells displayed phagocytic activity. After 2 to 6 weeks of vinyl chloride exposure, the principal organelle affected appeared to be the endoplasmic reticulum. Cisternae of the RER became dilated in a relatively small population of the hepato cytes in the 2-week treatment group. Four weeks after exposure to vinyi chloride, patches of dilated endoplasmic reticulum were prominently displayed in some hepa tocytes (Fig. 2b). At this stage the SER was relatively unaffected. In the 6-week treat ment group, vesicuiation of SER and dis tention of RER were easily discernible in a large number of hepatocytes (Fig. 2c). How ever, other cell organelles showed no de monstrable change. These changes, though, are still beyond the resolving limit of the light microscope. The nonhepatocyte com ponents showed minimum changes which
TABLE 2 Body Weights op Rats aipoas and apti* Vinyl Chumudc Exposunr*
Duration (weak)
2
4
6
Treatment
Normal control VC-oxpoaad Air control
Normal control VC-aapoaaO Air control
Normal control VC-aapoaad Air oontxoi
Initial weight <>
400 15 405 12 396 * 17
398 8 410 16 395 10
402 14 396 9 398 14
Final weight (I)
433 16' 396 14 414 IS
450 IS 421 15 4i9 5
486 14 398 10 449 4
Percctitigv gain
-2**
3'
13" 3* 6"
21" <l" 13"
* Aaalym of body wash* waa by rafruauon aoaiyaia followed by an anaiywa of vanaaea on tba rmiduais from tba rrurwiino aquation. (Raaadoal - obaarvnd final waitbt - predicted final weight from ii|raaaion aquation.)
* Normal control n vinyi chloride aapoaad. p < 0.05. ' Air control *i vinyi ebiorida axpnaod. p < 0.05. 4 Air control o normal control, p < 0.05.
CMA 003144
6 DU. TSENG, AND TAMBURRO
CMA 003145
VINYL CHLORIDE EFFECT ON ENCYVES
wers characterized by an increased accu mulation of lytosorr.al-like substances in some of the sinusoidal lining ceils as well as a greater tendency to accumulate lipids in the interstitial cells (Fig. 2d).
DISCUSSION
Glutathione conjugation is an important pathway for the metabolism of potentially harmful electrophilic metabolites of xenobiotics. Studies by Watanabe et al. (I976b,c) indicate this to be the maior route fer in activation of the vinyl chloride metabolites.
Glutathione-5-transferases are a group of cytosol enzymes catalyzing the reaction of glutathione and electrophilic compounds to form less toxic and more water-soluble con jugates. Their activity during chronic ex posure to xenobiotics, like vinyl chloride, could be a key determinate in the ultimate outcome of such exposures as illustrated by the longer arrow in Fig. 1. The increase in hepatic GEST activity at 4 weeks and the later increase in GAST activity at 6 weeks suggested that in the earlier stages of ex posures most of the chlorooxirane interme diate is being adequately detoxified. During the later stages of chronic exposure, more chlorooxirane may become rearranged to yield more chloroacetaldefayde and, in turn, react with other available glutathione trans ferases or become further metabolized to chloroacetic add. Alternatively, the exces sive chlorooxirane could rearrange sponta neously to form chiorocthanol and be further oxidized to chloroacetaldehyde, which in turn may react with glutathione, or be oxi
dized to monochloroacetic ac:d ,,':hm-cr.. 1967). This would be ;cr.3:z::r.t v;:h :he later increases in the aralkyl-transferases and the finding by Hefner et al. (1975) that monochloroacetic acid is found only in the urine of rats exposed for an extended time to higher levels (5000 ppm) of vinyl chloride. The increased use of alternate pathways, for chlorooxirane and chloroacetaldehyde de toxification. may reflect increased concen tration of these active metabolites allowing greater opportunity for DNA injury.
A single exposure to vinyl chloride de creased hepatic ncr.protein ;u!fhydryl com pounds in rats (Watanabe. 1976a); similar decreases of glutathione concentrations were produced in rats by other xenobiotics such as 1,1-dichioroethylene (Jaeger et aL, 1974a; Reichert et al., 1978) and acetaminophen (Mitchell et al., 1973). In the present study, repeated exposure to vinyl chloride caused a significant increase of nonprotein sulfhydryl concentrations (Table I) analogous to the elevation of glutathione concentrations seen after the administration of carcinogens to rats (Fiaia et al., 1976). In addition, the results showed that repeated exposure to vi nyl chloride also caused an increase in he patic glutathione-^-transferase activity (Ta ble 1) similar to that seen after the administration of phenobarbitai and 3-methylcholanthrene to rats (Mukhtar and Bresnick, 1976). These data suggest a mecha nism for compensatory synthesis of hepatic glutathione and glutathione-S'-transferases after repeated exposure to vinyl chloride.
The decreased concentration of cyto chromes P-450 found in rats after repeated exposure to vinyl chloride (Table 1) is con-
Fio. L (a) Poruoa of a hepotecyta from control. Stack* of roefh endoplasmic reticulum (RER) am
--f----< by many ovoid mitochondria (ML Chromatin it Sooty dwpanad in tho nacton* (NV9300X,
(b) Hepaioeyts aflw 2 nook* of vinyl chtorida expomru. Dilation of RER appeared widmpmd in thorn
two edh BUa (B) canaliculus appeared unaltered in iImh rata. 3300X. (e) Four weefea after vinyl
chloride exposure. Goipi complex (G) appeared unaffected while cuttmai dilation continued. Distinction
between SER and RER is compilestad by the detachment of riboaomaa. Lipid droplets (L) and glycogen
(GL) often
9500X. (d) A fat-<ionnf imontitial call is surrounded by seven! hopatocytaa
in a rinyl chloride treated animal. Unlike lipid itoted in hepetocytea, the shape of lipids (L) appeared
irregular in thnaa call*. SOOOx.
CMA 003146
8 DU. TSENG. AND TAM BURRO
sistent with work by Reynolds et al. (1975). This decrease in cytochromes F-450 content was also shown in vitro (Guengerich and Strickland, 1977; Ivanetich et al., 1977) sug gesting that a metabolite of vinyl chloride destroys the cytochrome. Mixed-function oxidase activity, with benzphetamine as sub
strate was unaltered. With regard to the structural alterations
produced by vinyl chloride, the present find ings confirmed previous observations on the selective effect of this carcinogen in the en doplasmic reticulum (Ou et al., 1979). A gradual increase in the number of hepatocytes affected and the involvement of both smooth and rough ER were shown in this study. The endoplasmic reticulum is the pri mary site of protein synthesis and its dilation suggested the presence of a vinyl chloriderelated effect. The lack of a concomitant Golgi hypertropy is noteworthy since this organelle serves as the site of glycosylation and packaging of many exportable proteins. It may be inferred that the vinyl chloride effect is mainly an intracellular phenome non. The relatively late involvement of SER could reflect a further attempt at detoxifi cation by the hepatocyte. The tendency for the interstitial cells to accumulate lipid and the heightened phagocytic activity correlate with increases in collagen formation and may be evidence of low-grade cellular injury. This may prove to be the initial histological response to vinyl chloride exposure.
Ultrastructural responses to chronic in halation of vinyl chloride were reported by Feron et al. (1979). Unlike our findings, the principal effects observed were swollen mi tochondria and some proliferation of SER. The mitochondrial swelling presumably re flects the extensive vacuolization observed by light microscopy. The discrepancy prob ably resulted from differences in the dose and duration in vinyl chloride exposure since Feron et al. (1979) exposed rats to 5000 ppm vinyl chloride for 52 weeks. Such an exten sive mitochondrial lesion could result in bio chemical modifications such as a change in
ATPase or cytochrome oxidase levels. The only enzyme activity measured, giucose-6phosphatase, was reduced.
The authors believed that the altered glu tathione metabolism, as reflected by the in creased nonprotein sulfhydryl content, and the increased activities of glutathione-5transferases and glutathione reductase, in rat liver after repeated exposure to high doses of vinyl chloride represent an early hepatocellular adaptation to vinyl chloride exposure.
ACKNOWLEDGMENTS
The authors wish to express their gratitude to the staff of the B. F. Goodrich Plant in Louisville, Kentucky, for their cooperation in the exposure studies, to Dr. Richard A. Greenberg for his review, to Mr. John P. Sandoz for his help with the statistical analysis, and Mr. John Kreisle and Ms. Debra S. Eadcs for technical as sistance.
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Bolt, H. M., Kappus. H,, Buchter. A, and Bolt, W. (1973). Metabolism of vinyl chloride; fencer I, 1423.
Bolt, H. M.. Kappus, H., Kaufmann. R., Appel, K. E., Buchter, A, and Bolt, W. (1976). Metabolism of l4C-vinyl chloride in vitro and in viwx truerm Sym posia Ser 52,151-164, (ARC Scientific Publications No. 13.
Carlsexo, L, and Mannervik, B. (1975). Purifica tion and characterization of the flavoonzyme gluta thione reductase from rat liver. J. Biot. Chem. 254, 5475-54*0.
Creech, J. L. and Johnson. M. N. (1974). Angios arcoma of liver in the manufacture of polyvinyl chlo ride. J. Oceup. Med. 16, 150-151.
Drew, R. T., Harper, C., Gupta B. N,, and Talley, F. A (1975). E/fecu of vinyl chloride exposures to rats pretreated with phenobarbitaL awea Health Perspec. 11, 235-242.
Du, J. T., and Tamburro, C. H. (1976). Decreased glucoee-6-phosphatase activity in liver in vinyl chlo ride exposed rats. Fed. Proe. 35, 329.
CMA 003147
INYL CHLORIDE EFFECT O'- ISZVMES
0
DC, J. T.. and Tam it* 3.0. C ,-i . iv'xi. iic'.i.sii glutathione content. giutuimone-j'-trafli.''-."ss und
glutatntone reductase ,n liver 01 rm exposed ;o vinyl
chloride. Fed Frtx. 37, 1543.
Du. J. T,, Sandoz, J. P.. Tseng. M, T.. and Tam-
burrO, C. H. (1979). Biochemical alterations in liv
ers of rats exposed to vinyl chloride. J. Toxicol. En
viron Health 5. 1119-1132.
Elmore, J. D.. Wono, j. L,, Laumbach, a. D,, and STREIRS. Li. N. (1976). Vinyl chloride mutagenicity
vu the metabolites chiorooxiranc and chloroucetal-
dehyde monomer hydrate. Biochtm. Biophyi. Acia
442. 405-419.
Feron, V, J,, Sm, B. J., Immel, H. R.. and Kroes. R. 11979). One*ye*r time sequence inhalation toxicity
study of vmyl chloride in rats. III. Morphological
changes in the iiier Tj.njjio^y la. 143-154.
FlALA. S.. MOHiNDRL, A.. KETTERING, Vv. G., FlALA. A. E.. and Morris. H. P. i1476). Glutathione and
gamma glutamyl transpepudasc in rat liver during
chemical carcinogenesis. J. Hat. Cancer Inst. 57.591 -
598.
Green, T.. and Hath*at. D. E- ( 1975). The biolog
ical fate in rats of vinyl chlonde in relation to its
oncogenicity. Chem.-Biol. Interact. 11. 545-562.
Green, T.. and HaThway. D. . (1977). The chem
istry and biogenesis of S<ontainmg metabolites of
vinyl chloride in rats. Chem.~Bioi, Interact. 17, 137-
150.
Greim, H_ Bonse, G., RAdwan. 2~, Reichert, D.,
and Hbnschler. D. (1975). Mutagenicity in vitro and potential carcinogenicity of chlorinated ethylenes
as a function of metabolic oxtrane formation. Biochem.
Pharmacol 24, 2013-2017.
Gross. H,, and Freiberg, i. (1969). Alpha-halo
ethers. 41. Existence of chlorocthylene oxide. J.
PraJel Chem 311, 506-510.
GuencErich, F. P., and Strickland. T. W. (1977). Metabolism of vinyl cfahxide: Destruction of the heme
of highly purifled liver micraeomsi cytochrome P-450
by s metabolite Mol. Pharmacol 13, 993-1004.
HaBIO, w. H.. PaBST, M. J.. and JaKOEY. w B. (1974). GluuthKMM-5-transferases. The first enzy-
matsc step in meicapturic acid formation. J. Biol.
Cham. 249, 7130-7139.
Hefner, R. E.. Watanaec P. G,, and Gcmring.
P. J. (1975). Preliminary studies of the fate of inhaled
vinyl ehiorida maaoner in rata. Ann M.Y. Acad. Sci
246, 135-148.
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IVANETtcx. K. M- Aronson, 1,, and Katz. t. D.
(1977), The interactioa of vinyl chloride with rat he
patic msenaowtai cytochrome P-450 In vitro. Blochem.
Biophyi. Rat. Common, 74, 1411-1418.
Jaeger. R. J.. Connolly, R. B^ and Murrhy. S. D.
(1974a). EfTcct of 18 hr. fast sad glutathione depic
tion on 1.1-dichloroethyiene-induced bepatotoxidty
and lcthaiity in rats. Exp. Mol. Pathol 29,187-198.
?.. J . Is1 '.oi-i. E. 5. f.`A LV. R 3.,
'IGSLIV M T..
i. V>D V,NV S. D.
I 1974b). Acute neoatic injury by vinyi chior.ue in rats pretreated with phenobarbetal. Mature 1Londoni 252,
724-726.
Johnson. M. K. (1967). Metabolism of chloroethanol
in the rat. Biochem. Pharmacol. 16, 135-199,
Kaplowitz. N. Kuhlenkamp, J.. ano Cl:f"on. 0. (1975). Drug induction of hepatic glutathionc-5transferases in male and female rata. Biochem. J. 146,
351-356.
Karevs. H.. Bolt. H. M.. Bvchter, a., and Bolt, W, (1976). Liver microsomal uptake of 'C-vinyl
chloride and transformation to protein alkylating metabolites in vitro. Toxicol Appi. Pharmacol. 37. 461-471.
i_.ua, R. J., and oOLT. H. VI. ( 19731. Formation ct 3.
V-einenocytidine moieties in RNA by vinyi cnionde metabolites m vitro end in vivo. Arch. To.ni.ji. 39,
235-240.
Lowry. O. H,, Rosebrouoh, N. J.. Farr, A. L. and Ranoall. R. J. (1951). Protein measurement with
the Folin phenol reagent J. Biol. Chem. 193. 265-
275.
Lu. A. Y H.. Kunztzman. R.. West, S., Jacobson, M.. and Connet. A. H. (1972). Reconstituted liver micrneomal enzyme system that hydroxyiates drugs,
other foreign compounds and esogenoua subetnte*.
/. Biol. Cham. 247. 1727-1734.
Malaveille, C. Bartsch. H_ Barbin. a- Camus. A. M.. and Montbsano, R. (1975). Mutagenicity of vinyl chloride, chlorocthylene oxide, chloromcetai-
dehyde and chloroethanol. Blochem. Blophvs. Res.
Common 63, 363-370.
Maltoni. C,, ano Lefemine. C (1975). Carcmogematy bioassays of vinyl chloride: Current results.
Ann. M.Y. Acad. Set. 246, 195-218. McCann. J., Simmon, V.. Stkeitwieser, D.. and
Ames. B. N. (1975). muugeaicity of chloroacetsldehyde. a possible metabolic product of U-dichlo-
methane, chloroethanol, vinyl chlonde and cyclo phosphamide. Proc. Mat. Acad. Set. USA 72, 3190-
3193.
Mitchell. J. R.. Jollow, D. J,, Potter, w, a., Gillete. J. R.. and Brooie. B. B. (1973). Acettminophen-indiiced hepttic necrosis. IV. Protective rote of glutathione. J. Pharmacol. Exp. Thar. 187, 211-
217.
Mukhtae. H., and Beisnick, E. (1976). Effects of phenobarbitel and 3-mathytchoUnthruM adminmn-
tion on glutathione-5- tpoxids transferase activity in rat liver. Blochem. Pharmacol 25, 1081-1084.
Omura. T.. and Sato, R. (1964). The carton mon oxide-binding pigment of liver wiernenmsa. I. Evi dence for its hemoptotoin oetare. J. Biol Chem. 239,
2370-2378.
Reichert, D,, Werner, H. w,, and Hsnschler. D.
CMA 003148
10 DU. TSENG, AND TAMBURRO
(1978). Role of liver gluuthione in l.l-dichloroethyleoe metabolism and hepetotoxidiy in intact rata and isolated perfused rat liver. Arch, Toxicol. 41, 169-- 178.
Reynolds. E. S,, Moslen, M. T,, Szabo. S., and JaeoeJL R. J. (1975). Vinyl chloride-induced deac tivation of cytochrome P-450 and other components of the liver mined function oxidase system: An in vivo study. Res. Common. Chem. Pathol. Pharmacol. 12, 685-694.
Sedlae, J., and Lindsay. R. H. (1968). Estimation of total protein bound and non-protein sulfhydryl groups in tissue with Ellman's reagent. Anal. Biochem. 25, 192-205.
VanDuuren. B. L~ (1975). Possible mechanism of car cinogenic action of vinyl chloride. Ann. S.Y. Acad. Set 244, 258-267.
Viola, P. L_. Bloom. A., and CatuTO, A. (1971).
Oncogenic response of rat skin, lungs and bones to vinyl chloride. Cancer Res. 31, 516-522. Watanase. P. 0., Heener. R. E.. Jit., and Gehiuno, P. J. (1976a). Vinyl chloride-induced depression of hepatic non-protein sulfhydryl content and effects of bromosuiphaletn (BSP) clearance in rats. Toxicology
6, 1-8.
Watanase. P. G., McGowan. G. R., and Gehring, P. J. (1976b). Fate of '*C-vinyl chloride after single oral administration in rats. Toxicol. Appl. Pharma col. 34, 339-352.
Watanase. P. G., McGowan, G. R,, Madrid, E. 0,, and Gehring. P. J, (1976c). Fate of uC-vinyl chlo ride following inhalation exposure in rats. Toxicol. Appl. Pharmacol. 37, 49-50-
Watanase, P. G., Zemeel. J. A., Peoo, D. G.. and Gehring, P. J. (1978). Hepatic macromoiecular binding following exposure to vinyl chloride. Toxicol. Appl. Pharmacol. 44, 571-579.
CMA 003149
5
Inmronmental Health Perxpectk'e* /ol. U. pp. U7-VJ2, lam
Effectiveness of Federally Required Medical Laboratory Screening in the Detection of Chemical Liver Injury
by Carlo H. Tamburro* and Richard Greenberg*
The increasing concern of industrialized societies over the potential health hazard of synthetic chemicals in the occupational environment ha* led to merment requirements for medical laboratory screening of workers. The specific tests for such screening programs are most often selected on the basis of medical experience which utilized them in symptomatic or hospitalized populations. Required screening tests for hepatic injury including cancer in vinyl chloride workers has been systematically and prospectively studied in an industrial population working with synthetic rubber and plastics. Approximately 1300 employees were studied over a five-year period. A cohort of 909 male employees, for the purpose* of analysis, were divided into a "standard" and "nonstandard" population bused upon the abuence or presence of significant medical disease (including liver disease). A suheohort of 121) individuals was further identified based on availabiliity of liver biopsy. Evaluation of federally required studies included alkaline phosphatase <AI'>. yxlutamyl transpeptidasc (GGTI*), alanine aminotranaerase (ALT, SGPT), aspartic itminolntnsfrrase (AST. SGOT) nnd bilirubin (UK). Also studied were indocyanine green clearance (It'd > nnd radioisotopic liver spleen scans I I..S scans). The (itiTl* provided the highest positive predicted value as a screening lest for identifying "nonstandard" individuals I individuals with all types of medical disease) followed hy ICG. AST. ALT, L-S scan, Al\ and BR.
In the identification of asymptomatic liver disease the GGTI' had the least specificity due to a high false positive rate, while the Al* provided the highest specificity. The ICG clearance however, provided the best combination of positive predictive value and sum of specificity and sensitivity. The AP provided additional increase in specificity as a follow-up study. There was no evidence that any of the other federally required tests added any additional benefit and did add significant increase in the false positive rate. These studies support the need for evaluating screening tests as to their sensitivity, specificity and positive predictive value, in asymptomatic individuals, before they are made established requirements.
Introduction
Industrialized societies throughout the world have become increasingly concerned over the poten tial health hazard of synthetic chemicals in the occupational environment. Governmental regula tions have increased the number and tyt>es of medical laboratory screening required for a large variety of halogenated hydrocarbons as well as other potential environmental hazards. The pri mary objective of these screening programs is to
Liver Research Center, Division of Digestive Diseases. Department of Medicine, and Department of Community Health and Cancer Center. University of Louisville School of Medicine, Louisville, Kentucky 40201.
October 1981
reduce disability, morbidity and mortality in work ers, especially as related to serious low-grade health hazards. In general, screening programs are instituted because of the presence in the work environment of a suspected or proven environmen tal toxin or carcinogen, which has the potential of producing low-grade injury over long periods of exposure.
Most screening studies are directed toward the detection of abnormalities in certain body systems. The specific tests are frequently selected on the basis of medical experience which utilized them in symptomatic or hospitalized populations. Prior expe riences utilizing nonspecific muitiphasic health sur veillance screening and maintenance have not proven to be cost effective except under certain limited
117
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conditions (i). The cost effectiveness of such tests, however, in the determination of medical screening requirements, has played a limited role due to the potential seriousness of these occupational agents. Little attention has been paid as to whether the effectiveness of federally required screening pro vides the best or, more importantly, a necessary benefit when applied to asymptomatic and other wise healthy worker populations.
The discovery in 1974 of hepatic toxicity and cancer formation in vinyl chloride workers provided the opportunity to systematically and prospectively study the effectiveness of federally required and federally recommended medical screening proce dures for the detection of chemical liver injury, including cancer development (2). Table 1 lists the federally required medical screening procedures since 1974 for environments utilizing vinyl chloride or polyvinyl chloride. Table 2 lists the federally recommended studies for these same environments. This paper will present a preliminary assessment of the effectiveness of these federally required studies in the accurate detection and identification of chem ically induced liver injury due to halogenated hydro carbons, especially vinyl chloride.
Materials and Methods
The industrial population studied consisted of approximately 1200-1400 employees of a chemical plant whose two major products were synthetic rubber and plastics. The industrial plant had been in operation for over 35 years and had a predomi nance of male employees (96%), approximately 80-87% of the work force being white, 11-12% black, less than 1% of other racial origins. Turnover of the plant was approximately 10 to 15% per year with 65-70% of the work force having worked five years or more at the plant. Employee ages ranged from 18-65, with a mean of 52 years.
A cohort consisting of 969 male employees who worked continually from June 1, 1976 to May 31, 1977 waa, for purposes of this analysis, divided into a "standard" and a "nonstandard" population. These designations were given on the basis of a review of
Tabic 1. Federalrequired itudiee for vinyl chloride workers.
History and physical < 10 years aa vinyl chloride worker--(annual) > 10 years as vinyl chloride worker--(semiannual)
Biochemical studies SGOT (AST) SGPT (ALT) GGTP AP TB
118
Table 2. Federally rccomim nded (not required) studies.
Hepatic studies LDH isoenzyme Total protein Protein electrophoresis Hb,Ay Radioisotonic scan
Kidney dysfunction (urine examination) Albumin RBC Exfoliative abnormal cells
Pulmonary system FVC FEV, Chest x-ray (PA and lateral)
all present standard medical data on each employ ee, including the federally required studies. Other screening studies of the medical surveillance pro grams were not utilized in the classification of overall medical status because, at that time, their clinical usefulness was unknown or controversial. All studies were performed on an annual basis; those individuals with ten years or more of employ ment were examined and screened semiannually. Compliance with medical screening studies during the five-year study period showed a continuous participation in the history and physical examina tions by over 75% of the work force, laboratory tests and chest x-rays by 86%, and liver-spleen scans by 85%. Seventeen percent failed to undergo at least one history and physical examination, 9% did not have any of the radiological studies, and only 4% failed to have laboratory studies during this period. Approximately 40-50% of these individuals who did not undergo an examination claimed to have been examined by their private physician.
A subcohort of 120 individuals was further identified based on the availability of a liver biopsy performed for medical reasons, both related and not related to their work.
The term "standard" is used for those individuals who, based upon the best medical opinion, demon strated no evidence of any significant medical disease, occupational or nonoccupational in origin. The "nonstandard" population included ail others not included in the standard population.
The subcohort population was divided into those individuals with and without histological evidence of liver injury and further subdivided into those with and without histological features characteris tic of chemical injury.
All employees had individual work histories. These consisted of a standardized job classification for all jobs within the plant since its opening and a
Environmental Health Perspectives
003151
CMA
peered or potentially hazardous heptaioxic chemi
cals used within the work place
The agents
were rank ordered on the basis of the intensity of
exposure for each of the job classifications for each
of the yean that the plant was in operation. From
this detailed work history, a cumulative exposure
ran month ration (CERM) was determined for each
employee for each of the 22 chemicals. All histologi
cal material was classified as to the presence or
absence of liver disease, and to whether the abnor
malities were consistent with chemical or non
chemical injury. This classification was conducted
double blindly by three experienced physicians,
two pathologists, and a hepatologist (6'), without
knowledge of any medical data, exposure or work
history.
Results
Although 50 or more biochemical screening tests were performed during this study period, this paper will limit itself to the evaluation of the federally required studies, the indocyanine green clearance (ICG) study at the 0.5 mg/kg dose (7, 8) and radioisotopic liver and spleen scan (9). The
SSS SUH- (n'i
ini)
(Jljl (103) (102)
>554 5555 '///
LIVER SPlEEJi SIZE
Ficus* 1. Poaitfr* predietit* vahMt of Jcroonm* twts in irtontiOwtion of tntdieal duwto in an asymptomatic working population (N - 989). AH those screening tot* with positive predicant values of greater than TO an shown except for indirect bilirubin (due to high number of congenital indirect hyperbdtrobineima) and tngtyceride determination. Above each bar in the graph an shown the sum values for sensitivity and spactfldty of each tast. They generally follow the same linking.
October 1981
Figure 2. Frequency with which clinical biochemical tests cor rectly reflex the presence of hepatic damage in chemical
workers suspected of having liver disease: (SGPT) alanine a.'RLiotrpnsferase 'ALT' 'GGT y-giutareyi transpepticiase, (SGOT) aaparttc aminotransfenae (AST). (Aik. Phoe.) alka line phosphatase, (ICD) isodtric dehydrogenase (ICG) Indo
cyanine Green clearances at 0.5 and 5.0 rog/kg doae.
federally required biochemical studies include alka line phosphatase fAP), v-glutamyl transpeptidase (GGPT), alanine aminotransferase (ALT/SGPT). bilirubin (ALT/SGPT). and the aspartic amino transferase (AST/SGOT).
The positive predictive values of these screening tests in identifying medical disease (including liver disease) in this asymptomatic working population are shown in Figure 1. The GGTP provided the highest positive predictive value as a screening test for "nonstandard" individuals. It also provided the highest sensitivity and specificity sum shown in brackets. The predictive value of the other tests, in decreasing positivity were ICG, AST, ALT, liver and spleen scan, AP, and bilirubin.
Further evaluations were conducted on the subcohort population in whom we had both histolog ical and biochemical data concerning hepatocellular damage. If one looks at only those individuals who received liver biopsies for suspected liver disease then one would find the percent of poeitive tests as illustrated in Figure 2. The ALT (SGPT), GGTP, AP and AST (SGOT) demonstrate a very high degree of sensitivity in identifying individuals with hepatic disease. As shown on the right, ICG clearances at the 0.5 mg/kg level provide a similar degree of sensitivity to SGOT and AP. The higher dose ICG clearance (5 mg/kg) appears to provide the most sensitivity for latent hepatic disease. These findings are consistent with the general medical experience with hospitalized patients.
Sensitivity alone however is not an adequat indicator of a test's screening value, especially when used in asymptomatic individuals. More appro priate evaluation of these tests' value as screening instruments are shown by their sensitivity, specificity
003152
. 0SSunt
Figure 3. Sensitivity and specificity of various biochemical screening tests and their sensitivity and specificity sum values (S & S) baaed on 78 with biopsy documentation of their hepatic status and all of the biochemical screening studies listed. All screening tests with S & S sums lesa than 110 (e.g. bilirubin and isodtric dehydrogenase, are not illustrated.
GROUP RATINGS
Figure 4. Correlation between the histologic findings on liver biopsy and each individual's average total vinyl chloride exposure based on their avenge CERM (Cumulative Expo sure Rank Months) ratings. Rankings: 1 - lowest possible exposure; 2 - minimal exposure, low levels; 3 - moderate exposure; 4 worked in areas subject to occasional high excursions, or frequently high and/or had intimate contact.
and sum values shown in Figure 3 in the biopsied subpopulation. Here again, y-glutamyl transpeptidase and ICG clearance (0.5 mg dose) show the greatest sensitivity for identifying individuals with liver disease. However, GGPT had the least specificity, reflecting its high incidence of false positives. Specificity increased with the use of AST, ALT, and ICG clearance. The alkaline phosphatase pro vided the highest specificity, suggesting that mild or low grade chronic hepatic injury due to environ mental agents may be activating hepatic AP syn thesis in the absence of biliary tract obstruction or cholestasis. The ICG clearances, even at the low dose (0.5 mg/kg), clearly remains the test with the best combined sensitive and specific screening study for detection of individuals with subclinicai hepatic
disease. This subcohort biopsied group was further exam
ined on the basis of the histological interpretation of their liver biopsies and their work exposure to vinyl chloride. All biopsied individuals were subdivided into three groups: 19 with histological evidence consistent with chemical liver injury; 30 with histo logical evidence of liver disease, nonchemical liver injury; and 29 with normal liver biopsies. Each of the histological subgroups were further subdivided based on their vinyl chloride exposure, on a scale of 1 to 4 (Fig. 4).
The chemical liver injury group contained the highest percentage of individuals with the highest average rating (CERM) for vinyl chloride expo sure. In contrast, with those with liver disease, nonchemical, and those with normal livers have a
120
more even distribution of individuals relative to their degrees of vinyl chloride exposure. '
In our previous studies we noted that almost all individuals with histologically specific lesion of vinyl chloride injury or angiosarcoma had a total average CERM rating of 3.5 or greater. The
asterisk in Figure 3 indicates the percentage of individuals in each of the three histological groups with exposure ratings of 3.5 or greater. Again, the chemical liver injury group have the highest per centage of individuals with the high exposure ratings. This further supports previous work U, 10) identifying focal hepatocellular hyperplasia as the earliest histological characteristics of chemical injury in liver disease.
A study of the frequency with which these tests are positive among those individuals with liver disease, based on their histological findings (chem ical versus nonchemical), provides additional data supporting the clinical observation that an increased AP has a greater specificity for chronic liver injury.
Figure 5 shows the ratio of the proportion of positive screening tests in those with histological chemical liver disease divided by the proportion of positive tests in those whose disease is not of chemical origin. All tests, independent' of their sensitivity and specificity for liver injury, were more frequently abnormal in the presence of nonchemical, subclinicai liver injury, except for AP. In contrast, AP was far more frequently abnormal in those individuals with chemical liver injury, which tended to be more chronic than acute and generally less severe.
Environmental Health Perspectives
CMA 003153
I ri IOO h
CLi-CHEVlCAL LfV= NJU^Y
' -L.'V^V
NON CHEMICAL
<H/-) Q
LPU i t2: 3v
AST ALT GOT? (SCOT) <SGPT)
TESTS
AP
ICG 0.3
FI'WitE 5. Frfqu*ncy with which binehemicaJ test* were abnor mal in '.ho** with different type of hepatic injury expremni aa a ratio: (CLI) chemical liver injury, (Ll liver iliwam.-. nondwmkaL
Discussion
This preliminary systematic review of the posi tive predictive values and the sensitivity and specificity of federally and some non*federally required tests for chemical workers provides the first scientific and biological basis for the selection of medical screening tests for liver injury in occupa tional environments. Although these commonly used medical tests have been found by clinical experience to be effective as diagnostic tools in the symptomatically ill or hospitalized population, little clinical work has been done to determine their ability to accurately separate biological variations from early latent or underlying disease in asymp tomatic individuals. Teats which provide very high false-positive-'rates (decreased specificity) such as GGTP, interfere with the screening process identi fication of the high risk worker by the extra time and cost required for repeat testing, the decreased productivity for the employer, the- employees' increased anxiety, and by the loss of confidence in the effectiveness of the testing program by both employees and employer. Determination of the sensitivity and specificity of screening studies for asymptomatic individuals is essential if effective recommendations are to be made a federal require ment. This evaluation process also provided the
October 1981
beet rr*6t.r*o '.icVc*wpinjj ciiiukiv^
/vwhj
for cfcs scresr.ir.if pro^Tum. Fir
pilTtit'-iidi' pOpCiiiiioil OI
in '.h;^
'V$
have shown that the assessment of hepatic function
is best accomplished by low dose ICG clearance (0.5
mg/kg). The ICG clearance is somewhat a more
complicated technique (i.e., injection of substance
and repeated biood sampling) hut requires nniy 10
min to perform, and neetls only one needle stick. In
exchange it provides the best singular screening
test for latent hepatic injury. If adequate medical
facilities are not easily accessible, then ALT should
be substituted. If either ICG clearance and/or ALT
studies are found to be abnormal, an AP should be
done and a diagnostic work-up instituted to deter
mine the etiolor,' \ll).
The rationale for these recommendations is based
on the actual study of chronic subacute chemical
injury in an asymptomatic population, not preselected
because of signs or symptoms. Therefore the test's
ability to correctly differentiate disease from
nondisease or one type of injury' from another is
more accurately determined. Chemical and envi
ronmental agents of low toxicity tend to produce
repeated or persistent injury which accumulates
over time. Tests which measure overall functional
capacity quantitatively or semiquantitatively, rather
than measuring acute low-grade injury over time
are more likely to detect changes. For this reason,
clearance or tolerance studies provide the best
means for identifying latent hepatic disease, while
enzyme studies like ALT. GGPT, and SGOT usu
ally reflect acute cellular injury of higher grade or
degree and cannot accurately reflex accumulative
damage until very late in the disease process. Tests
which provide information concerning the progres
sion or nonprogression of injury will be far more
helpful to the practicing occupational physician.
They provide him/her with a better capability to
discern between nonoccupational and occupational
disease, and the best available reassurance for the
worker of his or her safety while allowing the
greatest possibility for continued productivity and
employment.
Finally, these data provide a sound scientific
basis upon which to modify federal requirements.
The removal of specific testing requirements which,
with field experience, prove not to have any significant
positive predictive value, or effective sensitivity
and specificity will aid in reducing overall cost and
help maintain continued compliance by industry
and workers. There may be theoretical reasons to
maintain orcontinue some of the present federally
required screeningstudies, but these reasons should
be separately identified and not be confused with
the purposes of the more effective test in the
121
CMA 003154
detection of occupationally related liver injury. The capabilities and limitations of any new tests
or old tests for new screening purposes in detection of other potential occupational hazards, should be validated before making them a required screening procedure. This would lay the foundation for sys tematic determination of effectiveness of screening procedure against a proven standard. Unvalidated federal requirements provide the worker and employer with a false sense of security and safety by what is believed to be effective monitoring. More importantly, such a situation can lead to delay in effective correction of cause and disease preven tion.
Conclusions
Biochemical screening for hepatic injury in asymp tomatic chemical workers can be done most effec tively by the use of liver specific clearance studies. ICG clearance provides the best combination of positive predictive value and sensitivity and specificity for functional hepatic testing at the present time.
None of the present federally required studies provide any significant degree of sensitivity with out marked reduction in specificity in asymptomatic individuals.
The ALT (SGOT) is the most useful among those Federal tests presently required and the alkaline phosphatase may provide additional specificity as a follow-up study in those individuals with positive ICG or ALT screening studies.
There is no evidence that any of the other federal studies add any benefit and strong evidence that they significantly increase the false-positive results in well individuals.
All screening studies should undergo evaluation as to their positive predictive value and sensitivity and specificity in asymptomatic individuals before becoming permanent or established requirements.
Portions of this work were supported by National Cancer Institute Contract No-l-CN-55212 and Manufacturing Chem ists Association Grant.
The authors wish to acknowledge the help and cooperation of Hynson. Westcott & Dunning and B, F. Goodrich Chemical Company.
REFERENCES
1. Collen, M. F. Cost effectiveness of multiphasic health testing services. In: Multiphasic Health Testing Services, M. F. Collen, Ed., Wiley, New York, 1978, Chapter 17, Section F, pp. 487-530.
2. Creech, J. L., Makk, L., Whelan, J. G., Jr., and Tamburro. C. H. Hepatotoxicity among polyvinyl chloride production workers during first year of surveillance program. Gastro enterology 67: 786 (1974).
3. Greenberg, R. A., Tamburro, C. H., and Kupchella, E. C. Prospective medical surveillance program for detection and prevention of industrial related cancer. In: Prevention and Detection of Cancer; Part 1, Vol. 2: H. Nieburgs, Ed., Marcel Dekker, New York, 1978. pp. 1921-28.
4. Tamburro, C. H., Greenberg, R. A., Newby, L. G., and Turns, D. M. Implementation and assessment of a demonstntion cancer control detection and prevention program in a cohort of industrial workers. Program Contract #N01CN-55212 Final Report, Division of Cancer Control and Rehabilitation, National Cancer Institute. Betheeda, Mary land, 1978.
5. Greenberg, R. A., and Tamburro, C. H. Exposure indices for epidemiological surveillance of carcinogenic agents in an industrial chemical environment. J. Occup. Med., in press.
6. Tamburro. C. H., Makk, L-, and Popper, H. Early hepatic histological alterations among chemical (vinyl monomer) workers. Gastroenterology 77: A33 (November 1979).
7. Fortwengier, P., and Tamburro. C. H. Use of dye clearance m the detection of hepatocellular injury among vinyl chlo ride workers. Clin. Res. 23: 264A (1975).
8. Tamburro, C. H., Creech, J. L, Davis, A., and Greenberg, R. A. Indocyanine green clearance aa a prospective indica tor of hepatocellular chemical toxicity. Gastroenterology 75: 969 (1978).
9. Whelan, J. G., Jr., Greenberg, R., and Tamburro, C. H. Radioisotopic scans and gray scale ultrasonography in detection of liver damage. Gastroenterology 79:1129 (1960).
10. Popper, H. and Thomas, L. B. Alterations of liver and spleen among workers exposed to vinyl chloride. Ann. N.Y. Acad. Sci. 246: 172 (1976).
11. Tamburro, C. H. Chemical hepatitis, pathogenesis, detec tion and management. Med. CUn. N. Amer- 63: 545 (1979).
122 Environmental Health Perspectives CMA 003155
Reprinted from CANCER. Vol, 40, No. 6, Decem ber 1977. Copyright. 1977. by the American Can cer Society. Inc. J. B. Lippincott Company.
Printed in U.S.A.
URINARY GLYCOSAMINOGLYCAN PATTERNS TN ANGIOSARCOMA OF THE LIVER
Kevin L. Curran, BA, MS, Charles E. Kupchella, PhD,
H. MDand Carlo
Tamburro,
Glycosaminoglycans extracted from 24-hour urine specimen* from patient* with hepatic angiosarcoma and from normal/control* were separated as cetylpyridinium complexes into "hyaluronic acid," "chondroitin sulfate," and "heparin" fractions, then further separated and characterised by anion-exchange chromatography and hyaluronidase susceptibility. The chromato graphic pattern of the urinary chondroitin sulfate fraction in patients with angiosarcoma of the liver differed from those of controls in that there was a relative increase in the total amount of uronic acid in a hyaluronidase-resistant fraction and a decrease in a fraction susceptible to hyaluronidase digestion. These changes appeared to become more pronounced with advancing disease. Chromatographic pattern* and determinations of hyaluronidase susceptibility indicated that the resistant fraction was heparan sulfate and that the susceptible fraction was chondroitin-4-sulfate and/or chondroitin-6-sulfate.
Qatar 40:3030-3053, 1977.
he emergence of angiosarcoma of the urinary GAG or collagen degradative or syn
Tliver and its relationship to vinyl chloride thetic products. Preliminary studies in our labo exposure4,7 has prompted a search for methodrsatory, however, demonstrated an increase in
to detect this lesion. Although systematic both liver and urinary GAG in patients with
screening programs are currently in opera angiosarcoma, chronic active hepatitis, and cir
tion.
there is still no single chemical in rhosis. '* Most of the increase in urinary GAG
dicator which is specific for angiosarcoma or for occurred in the chondroitin sulfate fraction and,
changes which may precede this disease.
in contrast to what was found for normal and
The association of elevated tissue glycosami- other diseases, the urinary chondroitin sulfate
noglycans (GAG) with tumors, including angio fraction was the only uronic acid positive fraction
sarcoma, has been established.
n Glyco* found in the urine of seven of nine cases of vinyl-
saminoglycans are also known to be involved in chloride-exposure-associated liver injury other
normal connective tissue synthesis and collagen than angiosarcoma. This study was undertaken
deposition and are elevated in connective tissue to characterize more completely the urinary
disorders.11 Since angiosarcoma of the liver has "chondroitin sulfate" fraction in hepatic angio
both neoplasia and fibrogenesis in its etiology11 sarcoma.
GACi changes could be expected to serve to sig
nal the appearance of early lesions and may be useful in evaluating advanced lesions.
Galambos* suggested that since the liver con
Clinical Summaries Case l--(Hepatic Angiosarcoma--advanced)
tributes very little to the overall connective tissue of the body, hepatic fibrogenesis should not be expected to result in significant increases in*
A 46-year-oid white male worked as a chemical helper in a vinyl chloride polymerization plant for thirteen yrars prior to the diagnosis of angiosarcoma.
Twelve years after initial employment, the patient
From the University of Louisville. Cancer ('.enter, and the Price Institute for Surgical Research Health Sciences Cen ter, Louisville. Kentucky 40201.
This work was supported in pan by .in Amrrn11 ('.tnerr Six inv institutional Crnnt. IM-111. a grant from the H F CiM>dri< h Company, anti commit N()l-CN-ss212 wnh the N.iuun.i) ('.inicr Institute.
Addrrss fur rrprints1 C K. Kupi tiella, Canter (Voter. I niversitv ul Ciuisville. Louisville, KY 402111
\i i rptnl for pulilieal ion April Is |')?7
exhibited a persistent elevation of lactic dehy drogenase and underwent angiographic studies which demonstrated multiple areas of scattered tumor stain throughout both lobes of the liver with areas of central translucency consistent with the diagnosis of angio sarcoma of the liver.
f .xploralorv laparotomy and liver biopsy confirmed this diagnosis, and the patient was treated with adriamycin, cyclophosphamide, and methotrexate; an
3050
6
CMA 003156
No. 6
Glycosaminoglycans in Angiosarcoma
Lurran et al.
3051
initial response was associated with a decrease in the alkaline phosphatase activity, improvement in in docyanine green clearance and an increase in radio isotopic uptake in areas of previously defective up take. After completion of the chemotherapy course, hepatic function deteriorated and the patient under went partial hepatic lobe radiation (total dose of 5,000 rads) over a two-month period. Despite radia tion therapy, the clinical course continued to deterio rate with the development of ascites, peripheral edema, increasing jaundice, hypoaibuminetnia, and marked elevations of transaminases and alkaline phosphatase activities. This was followed by progres sive hepatic failure, hepatorenal syndrome and he patic coma. Autopsy findings showed extensive in volvement of the liver with angiosarcomatous tissue extending into the diaphragm and metastasis to retro peritoneal and mediastinal lymph nodes, lungs, right adrenal gland and cerebellum. The right lobe of the liver demonstrated near elimination of the angiosar coma, presumably due to the radiation treatment. Urinary GAG assays reported here were made on 24hour urine specimens collected over the two-week period before death (Fig. I).
Case 2 (Hepatic Angiosarcoma--moderately advanced)
A 54-year-old vinyl chloride polymerization worker was first employed as a polymerization vat cleaner 28 years prior to the diagnosis of angiosarcoma. Two years prior to diagnosis, the patient had persistent biochemical liver, abnormalities although he was oth erwise asymptomatic with a normal liver-spleen scan. Angiographic studies showed pciiosis hepatis. A liver biopsy revealed focal sinusoidal dilatation, mild chronic inflammatory reaction with portal fibrosis, Kupffer cell hyperplasia and dysplasia. Subsequent biopsies demonstrated continued sinusoidal diiitalion, atypical and dysplastic Kupllcr cells with premalignant changes. The peliosis hepatis pattern be came more pronounced and multiple radioisotopic defects were evident on liver scan. A repeat biopsy one year after initial biochemical abnormality demon strated malignant sinusoidal cells. The patient was treated with a combination of adriamycin, cytoxan, and methotrexate with limited clinical and biochemi cal response. Death was preceded by peripheral edema, ascites, progressive hepatic failure, and coma. The GAG analyses reported here were made 10 and 6 months before death (Fig. I, |middle|).
Materials and Methods
Twenty-four hour urine specimens were col lected from two patients with angiosarcoma of the liver, and from two normal controls.
Critic specimens were stored at -70"C until analysis. Cetylpyridinium chloride (Sigma Chemical Company, St. l.ouis) was added to the entire 24-hour volume to precipitate the CAGs
IS - HEMT1C AMGIOSAACOMA-Mvoncad --------- 1
Fits. I. Elution Patterns of the Urinary Chondroitin Sul fate Fraction. The glycosantinoglycsni (GAG) in a 24-hour urine specimen were precipitated with cetylpyridinium chlo ride (CPC.) and separated as 0.4 M NiCl soluble ("hyalu ronic acid"), 1.2 M NaCI soluble ("chondroitin sulfate"), and 2.1 M NaCI soluble ("heparin") fractions. Each fraction was then subjected to anion-exchange chromatography. Shown here are typical 1.2 M (chondroitin sulfate) fraction rlutinn patterns (Advanced - case I).
according to the method of DiFerrante.* The hyaluronic acid, chondroitin sulfate, and hepa rin fractions were eluted individually according to the method of Schiller et al. '* Cetylpyridinium chloride was removed14 and the GAGs were sub jected to anion-exchange chromatography as de scribed by Schiller et al.1* Glycosaminogiycan Tractions were applied to 1.0 X 44 cm AG1-X2 (200-400 mesh, chloride form) columns Bio Rad Laboratories, Richmond, California) and eluted stepwise with 0.0, 0.5, l.Q,-1.25, 1.50, 2.0, and 3.0 M NaCI. At a flow rate of 1.0 ml/min, approximately sixteen 10.3 ml fractions of each molar strength of NaCI were collected and a sample of each fraction was analyzed for uronic acid by the method of Bitter and Muir.' Stan dards of heparin (Nutritional Biochemical Com pany). chondroitin sulfate (Sigma Chemical Company), and hyaluronic acid (Nutritional liitxhcmical Company) were also evaluated by ion exchange chromatography.
The uronic-acid-positive fractions within each individual salt fraction were pooled, dialyzed to remove salt, and concentrated. The fractions eluted by 1.25 or 1.50 M NaCI were tested for
CMA 003157
3052
C.w kk D'uvnotr I9T
W 4P
I .hi - .
Source
Ratio f)( I otat Lromc Acid ' fcijted m i *5 M/1 3 M NaCI
Sorm.il Vorroal Nn^iosarroma. case 2,
pre<hemmherapyl
\nutmfirroni. <2.
nemoirt<r:rpy *
Nntfiosiifcomn. cn*e I.
.idv.inced
0 364 0 3lft
0.843
o 9?J
3 0<M)
\*t> l*br i<lvc(rtamimylvcaaH
in a 24-hour
urme ^pectmen were precipitated with refytpynciimum t hlurtde iCl'C) and icparaicd as t>4 \1 N*tO soluble
'"hvalurunic acid"'. I 2 M NaCl soluble ('`chnnrimuin
5uifate `\ and 2. i M NaCl soluble '"heparin1') fractions
The CPC wn removed from 'r.e : 2 M NaCl-f-PC*
soluOiiized fraction and the GAG* ojrther purified bv
amon-exchanye chromatography The total amount o(
GAG In the resulting 125 M and 1.50 M NaCl column-
eluted fractions was determined and the ratio of the
two fractions was calculated. (`One dav prior to begin
ning of chemotherapy: *Two davi following chemotherapy
initiation.)
uciu and ..c;;ar:n fractions revealed no auaiitae di.ferertccs urtween controls and angiosar
coma patients. The anion exchange column pat terns of the 1.2 M NaCl solubilized GAGs are shown in Fig. 1. Chromatography of the urinary "chondroitin sulfate" fractions of patients with angiosarcoma yielded a comparatively large, uronic-acid positive peak in 1.25 M NaCl The ratios of the total amount of uronic acid-positive material eluted with 1.25 M NaCl to the total amount eluted with 1.50 M NaCl are given in Table l.
The susceptibility of the GAGs eluted with I 25 or I 50 M NaCl to hvalurontdase degrada tion is given in Table 2. The GAG eluted with 1 25 M NaCl was 'psigtiint to hyaluronidase, 'he enzyme producing only a 43% reduction in tur bidity. The 1.50 M NaCl-eluted GAC fraction was 100% susceptible to hyaluronidase degrada tion.
Discussion and Conclusion
susceptibility to testicular hyaluronidase (Nutri tional Biochemical Company) using a modifica tion of the cetyltrimethylammonium-bromide, turbidimetric assay described by DiFerrante.*
Rksijlts
The major GAG fraction observed in all urines--both from normal controls or from pa rents with angiosarcoma--was the fraction so lubilized by 1.2 M NaCl/1% ceiylpyridinium chloride (the "chondroitin sulfate" fraction). Anion exchange chromatography of hyaluronic
Tails 2. Hyaluronidaac Susceptibility
Source
Depoiytnertzation %1
Hepartn, standard Hvaiuronic acid, standard Chondroitin sulfate, standard 1,25 M NaCl coiumn-eiuate. pooled
fractions from anfinnarrnmmmn palients 1 . .ill M NaCl voiumn-eiuatp. |united fractions from angwusmimaniui patient! 1.50 V| NCI coiumn-duate.
normal
5.0 93.1 97 6
4.3 S
100 0 100.0
1 t'.lycoMminoflveans isolated from unit* were tested for hyaluronidase susceptibility by measuring changes in turbiditv developed with the addition of retvlirimethvlammonium bromide following meubatam with hy;iiu/i>nidu.wNormal controls exhibited only minor amount* of 1.25 M NaCl column-eluted I <At and rnnsrqurrir lv do noi .i|i-
pear in this table.
The chromatographic pattern found here for controls conforms to urinary glycosaminoglycan distributions reported by others. "* These pat terns suggest that there was a relative increase in urinary heparan sulfate and a decrease in chondroiiin-4- and/or -6-sulfate in patients with hepatic angiosarcoma. This interpretation agrees with the Dowex 1-X2 chromatographic patterns reported by Kao and Leslie11 and by others.tl*
Heparan sulfate is reported to be partially susceptible to hyaluronidase digestion,1* and this correlates well with the observed 43% diges tion of the GAG in our 1.25 M NaCl fraction. Since heparan sulfate has been shown to be associated with blood vessels,* an increase in the urinary excretion of this GAG is not surpris ing in this vascular lesion. Also, chondroitin-4* and -6 sulfates are reportedly eluted from Do wex I-X2 columns with 1.50 M NaCl *'* and are stiveptible to hyaluronidase* suggesting that our 1.5 \( fraction is chordroitin-4- ,tnd/or chondroiun-fi-sulfate.
Assuming that urinary GAG patterns de scribed here are reflections of hepatic changes, it will be important to determine what processes these changes reflect, i.t,, those of neoplastic growth, fibrogenesis, or cell death. In this re gard, it should be noted that I) the ratio of heparan sulfate to chondroitin sulfate reported here for angiosarcomatous urine is similar to that reported for cirrhotic human liver tissue bv Becker,1 and 2) the shift from a hvaiuronidase-
| CMA 003158
No. 6
Glycosaminoglycans in angiosarcoma Curran it sr--------
3053
susceptible to a hyaluronidase-resistant GAG is consistent with the suggestion by Hutterer and Rubin11 that the stabilization of collagen de pends on a shift to a hyaluronidase-resistant GAG envelope surrounding the collagen bundle. Although Hutterer and Kuhin attribute this to an augmentation of dermatan sulfate. Decker1 reported that the GAG pattern in human cir-
rhosis was characterized by the augmentation of dermatan sulfate and heparan sulfate. If the ob served changes in urinary GAG are reflective of
vinyl chloride-exposure-associated flbrosis, the fact that fibrosis is a precursor of angiosarcoma11 indicates that the observations reported here constitute a promising lead in early detection of vinyl-chloride-induced liver disease.
RKFF.RF.NCKS
I Anghileri, I.. J.: Metabolism of arid mucopolysaccha rides m hepatoma and normal liver Ontology V) 304-11"\ 1974
2, Becker. K. Acid mucopolysaccharides in experimental and human cirrhosis. In Collagen Metabolism in the laver, H. Fopper and K. Becker. F.ds. New York, Stratton Interinntincntal Medical Book Corporation, 1973, pp, 43-32.
3 Bitter. T. and Muir. H.: A modified urnnic acid carha/olc rraction. Anal. Ihocturn. 4:330-334, 1962.
4 Creech, J, I... and Johnson, M. N.. Angiosarcoma of ihc liver in the manufacture of pnlvvinvl chloride. J OcntpaImmil Mo! 16 ISO |S|, 1974
3 Itil'Vrraiilr, N.: `Hie iiirtisitretiiciit ul urinary uiutopolysaccliariiies. Anal. Huichm. 21 9H lllti. 1967
6 I til'crratur. N.: Turbidimetnc measurement of arid mucniHiIvsuerhnridrs and hyalurnnidosr amvity. J. Bui. Chon. 221) 303-306, |936.
7 Falk. II.. Creech. J. I... Heath, I). W . Johnson. M. N,, and Key, M .VI.; Ilqiatic disease among workers at a vinvl chloride polymerization plant. JAMA 230-59-63. 1974,
8 fialambos. J. T . Connective tissue metabolism and cirrhosis. In Collagen Metabolism in the laver, II. Popper and K. Becker, Kds. New York. Stratton Intercontinental Medical Book Corporation, 1973; pp. 37-61.
9 Casir. C . and Casic. T Removal of sialic acid from the cell coat in tumor cells and vascular endothelium and its effects in metastasis. /W Atoll. Acad. Set. I'.S.A. 48:1177. 1177. 1962.
10 flreenherg, R, A., Tamburra, C. II.. and Kuprhrlla, C. K. A prosfieetivr medical surveillance program for the drtcction and prrvrmion of occupationally-related tancer to 1`revcntion and Detection of Cancer. II. K. Nidlings,
Kditor. Part I, Volume 2, Marcel Dekkcr, Inc., NY (In
press).
II Hutterer. F , and Ruhin. K,. Mucopolysaccharides in
reversible and irreversible experimental hepatic fibrosis. In
Collagen Metabolism in the laver. It. Popper and K.
Kecker. Kds, New York, Stratton Intercontinental Medical Book Corporation. 1973; pp, 33-56.
12 Kao. K, Y T,, and Leslie, J. Cl Micro fractionation and determination of unnarv glycosaminoglycans. Biochm. MrH. 9-317-326. 1974
13 Koi/umi, T,, Nakamura. N., and Abe, H., Changes in
arid mucopolysaccharide in the liver in hepatic fibrosis. Him him. Ilmphys. Acta. 148 749-756. 1967
14 Korn. K. I). Isolation of heparin from mouse mast (ell tumor, J, Ihoi. (Jim. 2.34:1325-1,329. 1959,
15 Kupchella. C, K., and Tamburro, C, H. Urinary and i issue glyroxanunoglyran patterns in hqiatic angiosarcoma. In Prevention and Detntion of Cancer. II. K. Nicburgi, Kditor, Part I. Volume I, Mated Ddcker, Inc., NY (In press).
16 Makk, I... Creech, |. I... Whelan. |. (i., and (ohnson. M N Liver damage and angiosarcoma in vinyl chloride workers: A svsirmatg- detection program. JAMA 230:64-68, 1974
17 Popper. II., and Thomas. I., B. Alterations of liver and spleen among workers exposed to vinyl chloride Ana. M Acail. Sa. 246:172-194. 1975.
18, Rich, C., and Myers. W P. L.. Excretion of acid mucopolysaccharides in the urine of patients with malignant
neoplastic diseases. 7. l-ah- and C/hi. .Wad. 54:22.3-228. 1959 19 Schiller, S., Slover. C A., and Hodman. A., A
method for the separation of acid mucopolysaccharides: Its application to the isolation of hqiann from the skin of rats. J. Hut. (hum. 236:983-987, 1961
211 Sharon, N.: Complex Carbohydrates: Their Chem istry. Biosvnihrxis, and Functions. Reading. Massachusetts. Addixon-Wcslcv Publishing Company, 1975,
21. Varadi, I). P , Cifunelli. J A,, and Dorfman. A.: The acid mucigHilysaccharides in normal urine. Buchan. Buphyi. Ana. 141:103-117. 1967
22. Yamamoto, K., and Terayama. H.: Comparison of cell mat acid mucopolysaccharides of normal liver and vari ous ascites hqiatoma cells, Cancrr Ha. 33:2257-2264. 1973
CMA 3159
Prevention and Detection of Cancer
PARTI. PREVENTION Volume 1. Etiology
Edited by Herbert E. Nieburgs
Mount Sinai School of Medicine of The City University of New York New York, New York
COPYRIGHT O 1977 by MARCEL DEKKER, INC*
MARCEL DEKKER. INC. New York and Basel
CMA 003160
URINARY AND 1 ISSUE GLYCOSAMINOGLYCAN PATTERNS IN HEPATIC ANGIOSARCOMA
Charles E. Kupchella and Carlo H. Tamburro
Cancer Center and Department of Medicine University of Louisville School of Medicine
Louisville, Kentucky 40201
I. INTRODUCTION
The recent discovery of a relationship between vinyl chloride'and angiosarcoma of the liver has received much attention {1-3). Although there are now systematic detection programs for vinyl chloride workers (3,4), there is as yet no specific chemical abnormality that serves as a good indicator of early, vinyl-chloride-induced liver injury and angio sarcoma. Alpha feto-protein has been a relatively valuable serological marker for hepatocellular carcinooia (S). but is has not as yet proven use ful in the detection of angiosarcoma (6). New leads are needed if more specific tests are to be developed for angiosarcoma.
The literature suggests that the glycosaminoglycans in the urine and/or blood should be evaluated as a possible aid in early detection. The production of sulfated glycosaminoglycans is characteristic of malig nant vascular tiaaors of the skin and some pathologists use this feature as a diagnostic aid (7). Barr and Bonin (8) observed a strong positive alcian-blue, glycosaminog1yean staining reaction In human angiosarcoma tissue and suggested than an attempt be made to qualitate and quantitate the production of glycosaminoglycans in the neoplasms, senm, and urine of those at risk. They pointed out that the urinary glycosaminoglycans may have diagnostic significance in angiosarcoma and, if so, a glycosamlnoglycan spot test might easily be employed as a gross screening test of vinyl chloride production workers.
A number of other observations place the glycosaminoglycans in a relevant position with regard to angiosarcoma. Angiosarcoma is accom panied by connective tissue abnormalities (2,9) and changes in tissue, urinary, and blood glycosaminoglycans have been found to occur In many connective-tissue disorders -- including connective tissue disorders of the liver (10-14) -- as well as in hepatic cancer (15-17).
Supported in part by grants from the B. F. Goodrich Company and the American Cancer Society (IN-111) and a contract with the National Cancer Institute (NOl-CN-55212).
915
CMA O033-61
The purpose of this study was to make a prel iruinary determination of the glycosaminoglycan patterns in tissue and urine associated with angiosarcoma of tne liver and with vinyl-chloride-induced liver injury other than angiosarcoma and to compare these patterns with those in rcrta! control: arc those associated with other liver disease. Cur goal was to evaluate tne use of glycosaminoglycan patterns in the early detec tion of vinyl-chloride-induced liver injury and angiosarcoma and to explore the role of the glycosaminoglycans in the etiology of vinyl chloride injury.
It. PROCEDURES AND MATERIALS USED
Urine specimens were collected as occasional samoles from: 9 normal controls; 9 individuals with histories of occupational exposure to vinyl chloride and having aonormal, liver, biocnemical studies; 6 with '`other11 cancers prior to surgery; 3 with angiosarcoma; 3 with active viral hepatitis; 6 with cirrhosis; 2 with lung-liver metastases; and 4 with metabolic disorders of the liver (congenital and indirect hyperbiliru binemia) .
In one case of angiosarcoma. 24-hr urines were collected on alter nate days beginning 2 weeks prior to death.
Urine samples were collected without preservative and frozen at -76 until analysis. Specimens were divided into two 25 ml samples and one 5 ml sample. Urinary creatinine was measured on the 5 ml sample using a Technicon Autoanalyzer. The degree of urinary glycosaminoglycan polymerization was estimated by dialyzing one 25 ml sample for 24 hours in tap water; the sample was then treated Identically to an undialyzed sample by the method of DiFerrante (18) using cetylpyridinium chloride as a precipitant. After resolubilization of the glycosaminoglycans in water, duplicate samples were assayed for total uronic acid by the modi fied carbozole reaction of 8itter and Muir (19). The remaining glyco saminoglycans were reprecipitated with cetylpyridinium chloride and separated Into the wash, hyaluronic acid, chondroltin sulfate, and heparin fractions as described by Schiller et. al.(20). Each of the fractions was assayed for uronic acid ( ug per mg of creatinine).
Autopsy tissue was obtained In 2 cases of hepatic angiosarcoma (tumor tissue and non-tumor tissue adjacent to tumor), 2 cases of cirrhosis, and in 3 control cases (gun-shot wound victims without liver pathology) and analyzed for glycosaminoglycans by a previously reported modification (21) of the method of Schiller et. al. (20). Uronic acid was determined in each of the hyaluronic acid, chondroltin sulfate, and heparin fractions.
Pieces of tissue were subjected to alcian-blue-perlodlc-acldSchiff staining with and without hyalurpnidase and diastase pretreatment. These procedures were carried out according to the methods described by Mowry (22).
Ascitic fluid was also obtained at autopsy in one case of angio sarcoma and analyzed for glycosaminoglycans. The fluid was centrifuged
916
003162
CMA
and the sediment analyzed as tissue above. The supernatant was treated by the method for urine described above.
III. RESULTS
A summary of the urinary glycosaminoglycan measurement is given in Table I. Normal controls had the least urinary glycosamlnog1yeans (measured as uronic acid) of all groups. All other groups showed some elevation. The levels in angiosarcoma, hepatitis, cirrhosis, and liver metastases were significantly elevated (P < .05) over normal controls. The cirrhotic group exhibited the greatest variance in urinary glycosaml* noglycans. No significant differences were found In urinary creatinine levels between groups.
There were no significant differences between groups in either the percentage of the total glycosaminoglycans that was dialyzable (Table I) or in the percentage of the unfractionated total that appeared in the hyaluronic acid, chondroitln sulfate, and heparin fractions.
Seven of 9 vinyl-chloride-exposed individuals other than those with angiosarcoma had positive chondroitln sulfate fractions with nega tive hyaluronic acid and heparin fractions. This was true In only 3 of 32 other urines evaluated in this same manner.
The pattern of daily glycosaminoglycan excretion prior to death
due to angiosarcoma in one individual is given in figure 1.
Total tissue glycosaminoglycan levels for angiosarcoma timnrs. fibrotic tissue adjacent to twors, cirrhotic liver tissue and normal liver tissue are shown in Figure 2. Fractional hyaluronic acid, chon droitln sulfate, and heparin levels are given in Figure 3.
Hlstochemlcally, angiosarcomatous tissue exhibited a strong alclanblue positive staining reaction. Alclan-blue staining was only slightly less in "non-tumor" tissue adjacent to tirnior masses. The staining reaction In tissue from normal liver was very weak and only slightly stronger in cirrhotic liver tissue. The strong alclan-blue reaction In angiosarcomatous tissue did not occur if sections were pretreated with hyaluronldase.
Ascitic fluid sediment was uronic-acid-positive In only tijehyaluronic acid fraction -- H2 yg uronic acid per gram of dry, defatted sediment; ascitic fluid supernatant contained 1.7, 1.2, and 0.2 AJ9 uronic acid per ml in the hyaluronic acid, chondroitln sulfate, and heparin fractions, respectively.
IV. DISCUSSION
The literature indicates that normal male creatinine excretion Is 1.5 g per 24 hrs (23). Thus, our normal mean (Table I) of 3.2 .4 ug cetylpyrldlnium chloride-precipitable uronic acid per mg creatinine falls in the middle of the normal ranges reported by Varma et. al. (24),
917
CMft 03163
1
2.6 - -.7 .j/'-o; 2iFrnr.: pro V:' (25
LesHe '26', l'3 - i.?
3
a.*a `Co ino
Although our study was not controlled for age. Goldterg and Cotlier
(27) have shown that urinary glycosaminoglycan excretion is constant from ages 20-70. Hanley et. al. (28) nave shown that the proportion of urinary glycosaminoglycans in tne chondroitin sulfate fraction is constant from ages 20-70, Man'ey et. al. also reoorted that the tno^droi ti-i sulfate fraction is highest at birth and that it gradually drops until age 20, suggesting that urinary chondroitin sulfate reflects tissue growth.
The fact that we found no differences between grouos in the
creatinine concentration is significant in that it indicates that occa
sional samples do reflect 24-hour excretion when normalized to creatinine.
Precedent for expressing glycosaminoglycan measurements as a function of
creatinine content in occasional urine samoles nas oeen establisned by
Oirer-*nte and rich (25) arc
(23;. ''=*. 1 a> at. al. ,'221 rz.s
sncwn that tne creatinine/verne acid ratio is staacy from ages 20-7C.
Our results indicate tnat the liver diseases evaluated are accom panied by elevated urinary glycosaminoglycan excretion. Our tissue data suggests that this reflects liver-tissue glycosaminoglycan elevation and conforms to the reports by others that both hepatic connective tissue disorders (10-14) and heoatic cancer {15} result in ire-eased hepatic glycosaminoglycan levels. It may be significant that the angiosarcoma patients had half the urinary glycosaminoglycan excret'on of patients with liver metastases and tnat our analysis of angiosarcomatous tumor tissue exhibited half the glycosaminoglycan content reported by Kojlma et. al. (15) for hepatocellular carcinoma.
While our data suggest that liver disease results in a decrease in the proportion of highly polymerized glycosaminoglycans, variance was large within each group and none of the differences Oetween groups were
statistically significant.
Although we have not completed the characterization of isolated glycosaminoglycan fractions, our data indicate: 1) that the chondroitin sulfates are the primary urinary glycosaminoglycans in both normal controls and in disease states; 2) that the chondroitin sulfates and heparin are the dominant glycosaminoglycans in normal and cirrhotic livers (Figure 3). Chondroitin sulfate is elevated in the fibrotic, nontunor, portions of angiosarcomatous livers while heparin is the predomi nant glycosaminoglycan in tumor tissue. Hyaluronic acid is also apparent ly elevated relative to chondroitin sulfate In angiosarcomatous tumors
(Figure 3); and 3) that hyaluronic acid is the sole glycosaminoglycan
in ascites fluid sediment.
These qualitative data are in general agreement with those reported by others. Goldberg and Cotlier (27), Douglas et. al. (30), and farm* et. al. (24) have reported that the chondroitin sulfates are the predominant urinary glycosaminoglycans. ' Varma et. al. reported that 2/3 of urinary glycosaminoglycans are chondroitin-4-and chondroitin-6-sulfate and this agrees with our data on normal controls and on those with liver disease.
Kojlma et. al. (15) reported that in hepatocellular carcinoma
') 18
003164
tissue, chondroitin sulfates and hyaluronic acid were increased 33 and iu times, respectively, over amounts found in healthy livers; the heparin and heparan sulfate proportions dropped. This contrasts with our data on angiosarcoma tissue, i.e. heparin and hyaluronic acid increased S and 10 times, respectively, over normal tissue; chondroitin sulfate levels rose but fell in proportion to other glycosaminoglycans. Galambos and Shapira (10) reported that the chondroitin sulfates are dominant in normal livers and in hepatic fibrosis, but Kojima et. al. (15) report that chondroitinase-resistant and hyaluronidase-resistant glycosaminogly cans are dominant. Kuroda et. al. (31) also reported that heparan sulfate is the dominant glycosaminoglycan in the normal liver. Our histochemical observation that nearly all of the increased alcian-blue positive material in angiosarcomatous livers was susceptible to hyaluronidase digestion suggests that the observed chondroitin sulfate elevation is due to chondroitin-4- and/or chondroitin-6-sulfate.
The increases in liver and urinary glycosaminoglycans may well reflect an important role of these substances in the process of fibrogenesis and in tumor growth. Galambos and Shapira (10) reported that hyaluronic acid was elevated during hepatic fibrogenesls. If a similar fibrotic process is operative in angiosarcoma. It may be that the ob served tunor-tissue heparin increase is reflective of tumor growth. We did observe a four- to six-fold greater heparin level in tumor tissue than in adjacent, non-tumor tissue.
The observation that the chondroitin sulfates tend to be the exclusive uronic-acid-positive constituents in the urine of individuals is paradoxical in that those glycosaminoglycan fractions that are most elevated in angiosarcomatous tissue are those that are absent from the urine of individuals who may well have early, vinyl-chloride-induced liver injury. This pattern may be due to the selective action of lyso somal, glycolytic enzymes in the liver and/or may reflect the role of the chondroitin sulfates in early fibrotic changes In the liver. Certainly the potential usefulness of this pattern in early detection warrants the more complete evaluation now ongoing in our laboratory.
V. SUMMARY
Glycosaminoglycans were measured in urine and tissue of patients with hepatic fibrosis and hepatic cancer including vinyl-chlorideexposure-associated liver Injury and angiosarcoma. Angiosarcoma, hepa titis, cirrhosis, and liver metastatic patients exhibited significantly elevated glycosaminoglycan excretion. Angiosarcoma tissue exhibited, elevated glycosaminoglycan levels with the greatest increases in the heparin fraction. Histochemically, angiosarcomatous tissue gave a strong alcian-blue staining reaction which could be prevented by pretreatment with hyaluronidase. Although vinyl-chloride-exposure-associated liver injury other than angiosarcoma was not accompanied by a significantly elevated glycosaminoglycan excretion, this condition tended to be associated with a urinary glycosaminoglycan excretion pattern In which the chondroitin sulfate fraction was the only uronic-acid-positive fraction.
919
CMA 003165
TABL !. Urinary Glyccsariircglyoan Levels in _g Uronic AciJ per mg Creatinine oy Liver Diseases Category
Patient grouo
normal control
vinyl chloride exposed
Cases 9 9
ug uronic acid per mg creatinine
(* 1 S.E.)
3.2 * .4
4.1 i .4
i uronic acid not dialyzable
(* 1 S.E.)
65 * 5
39 i 6
other cancer
6
4.5 t 1.5
39 t 6
other liver disease
4
5.1 i 0.8
37 t 13
angiosarcoma hepatitis
3
3
7.6 * 1.6 8.5 1.8
41 t 22 52 i 14
Cirrhosis
6
12.7 i 3
53 * 9
1 iver metastasis
2
13.8 .9
42
003166
CMA
920
DAYS MlOft TO Liven DEATH FIG. 1. Urinary glycoaaainglycan output in ana angiosarcoma patient during the 16-day period prior to death.
921
CMA 003167
89TE00
4200 r*
o zoft
l^AJ--O' OO
<KN0)
II!
--------------------- ANGIOSARCOMA------------------------ -------------- ClHKllOSlS --
TumiH
Non* lufflor A4|0Cnl
T umw
Non luntof AO|Kinl
Cotol
Com l
Com 2
Com 2
Com 3
Cum A
--
- NORMAL
Cos# *3 Cant 6
FIG. 2. Glycosaninoglycan concentration in ungiosarconatous, cirrhotic and noragl huaan liver tissue.
jfl
Com 7
i
-- ---------------------------- ANGIOSARCOMA---------------------------------- ----------- CIRRHOSIS-------- --.------------ NORMAL--------
Tumor
Non-lumot Adiacanl
Tumor
Nan-tumor Adiocml
Cat* I
Com I
Cot* 2
Cm* 2
Cat* 3
Cat* 4
Cat* 3
Cat* 6
FIG. 3. Fractional concentrations of glycosaainog1yeans In anglosarcoaatous, cirrhotic and normal hiaaan liver tissue.
O Uol
cri
vo
i'I. REFEP.E.'ICES
1. Creech, J. l. and Johnson, M. N. Angiosarcoma of the Liver in the
Manufacture of Polyvinyl Chloride. J. Occuo. Med. 16: 150-151,
1974.
--
2. Falk, H., Creech, J. L., neatn, 0. W., Jonnson, M. N., and Key, M. M.
Hepatic Disease Among Workers at a Vinyl Chloride Polymerization Plant. JAMA 230: 59-63, 1974.
3. Makk, L., Creech, J. L., Whelan, J. G., and Jonnson, M. N. Liver Oamage and Angiosarcoma in Vinyl Chloride Workers: A Systematic Detection Program. JAMA 230: 64-68, 1974.
4. Creech, J. L,, Makk, L., Whe'an. rd "arl:u'`"0, C.
-eratcto*'.-
city Among Polyvinyl Chlor^oe Proouction Worvers During First
Year of Surveillance Program. Gast-oenterology 57; 736, 1974.
5. Kohn, J. and Weaver, P, C. Serum Alpha Fetoprotein in Hepatocellular Carcinoma. Lancet 2: 334-336, 1974.
6. Tamburro, C. H., Makk, L. and Creech, j. L. Unpublished observation.
7. , Girard, D., Johnston, W. C., and Grahm, J. H. Cutaneous Angiosar coma. Cancer 25: 363-333, 1970.
8. Barr, R. and Bonin, M. "Letters." JAMA 231(91: 914, 1975.
9. Popper, H., and Thomas, L. 8. Alterations of Liver and Spleen
Among Workers Exposed to Vinyl Chloride. Ann. NY Acad. Scl. 246: 172-194, 1975.
10. Galambos, J. 7., and Shaoira, S. Natural History of Hepatitis:
IV Glycosamlnoglycuronans and Collagen in the Hepatic Connective Tissue. J. Clin. Invest. 52(111: 2952-2962, 1973.
11. Koizumi, T., Nakamura, N., and Abe, H. Changes in Acid Mucopoly saccharide in the Liver In Hepatic Fibrosis. 8iochim. Siophys.
Acta. 148: 749-756, 1967.
12. Kojima, J. Studies on the Metabolism of Hepatic Connective Tissue in Fibrosis of the Liver. Med. J. Osaka Univ. 16; 419-429, 1964.
13. Rubin, E. Autoradiographic Characterization of Sul fated Acid Mucopolysaccharides In Experimental Cirrhosis. J. Histocham. Cytocham. 14: 688-689, 1966.
14. Patrick. R. S. and Kennedy, J. S. The Synthesis of Sulfated
Mucopolysaccharide at Sites of Hepatic Fibrosis Induced by Carbon Tetrachloride, Amyloidosis, and the Implantation of Catgut. J. Pathol. Sacterlol. 38: 549-555, 1964.
15. Kojima, J., Nakamura, N., Kanatani, M, and Ohmori, K. The Glycosaminoglyeans in Human Hepatic Cancer. Cancer Res, 35(31: 542-547, 1975.
924
CMA 003170
16. Anghileri, L, J. Metabolism of Acid Mucopolysaccharides in Hepatoma and in Normal Liver. Oncology 30: 304-317, 1974.
17. Yamamoto, K., and Teryama, H. Comparison of Cell Coat Acid Muco polysaccharides of Normal Liver and Various Ascites Hepatoma Cells. Cancer Res. 33; 2257-2264, 1973.
18. DIFerrante, N. M. The Measurement of Urinary Mucopolysaccharides. Anal. Blochem. 21.: 98-106, 1967.
19. Bitter, T., and Muir, H. A Modified Uronic Acid Carbazole Reaction. Anal. Blochem. 4: 330-334, 1962.
20. Schiller, S., Slover, G. A., and Dorfman, A. A Method for the Separation of Acid Mucopolysaccharides: Its Application to the Isolation of Heparin from the Skin of Rats. J. 8iol. Cham. 236(4): 983-987, 1961.
21. Kupchella, C., and Steggerda, F. The Distribution of Acid Muco polysaccharides in the Canine Gastrointestinal Mucosa. Trans. NY Acad. Sci. 34: 351-360, 1971.
22. Mowry, R. U. Alcian Blue Techniques for the Hlstochemical Study of Acidic Carbohydrates. J. Histochem. and Cytochem. 4: 407, 1956.
23. Sunderman, F. w. and Boerner, F! Iftfrmal Values in Clinical Medicine. W. B. Saunders. Philadelphia, p. 353, 1949.
24. Varma, R. S., Varma, R., Allen, M. "$., and Wardl, A. H. Urinary Excretion of Acid Mucopolysaccharides in Schtzophrenia. Biochem. Med. 11(4): 358-369, 1974.
25. DIFerrante, N. and Rich, C. The Determination of Acid Ami nopoly saccharide in Urine. J. Lab. Clin. Med. 48: 491-494, 1956.
26. Kao, K. and Leslie J. Micro Fractionation and Determination of Urinary Glycosamlnoglycans. Biochem. Med. 9(4): 317-326, 1974.
27. Goldberg, J. and Cotlier, E. Specific Isolation and Analysis of Mucopolysaccharides (Glycosamlnoglycans) from Human Urine. Clin. Chim. Acta. 4jL 19-27, 1972.
28. Manley, G., Severn, M. and Hawksworth, J. Excretion Patterns of Glycosamlnoglycans and Glycoproteins in Normal Human Urine. J. Clin. Pathol. 21.: 339-345, 1968.
29. Pennoek, C. A. A Modified Screening Test for Glycosaminoglycan Excretion. J. Clin. Path. 22: 310, 1969.
92S
CMA 003X71
20. Oouglas, C.. Nowak, J. and Cares, B. Mucopolysaccharides in -''ns Curing Normal Hunan Bevelopment. Rediatr. Res. Tj. 724-727, `.0.73.
31. Kuroda, J., Saito, S., Seno, N.. Nagase, S., and Anno, K. Isolation and Chemical Characterization of Mucopolysaccharides from Rat 7,,mors, Cancer Res 34(2): juo-312, 1974.
003n2
926
[CANCER RESEARCH 41. 419-424, Fubruary 19*1) OOOS-S472/91 /0041-0000*02.00
Tissu and Urinary Glycosaminoglycan Pattems^A3SOttiaxeawi^a&i!ftt an Intermediate, and a Slow-growing Morris Hepatoma*1
8
Chariot E- Kupcholla,2 E. Elaine Drake, Jeffrey Kennedy, Kevin L. Curran, Raya Warick, and H. P. Morris
C*ne*r Cinnr. Unwwwly el LaumMe. Lowmee, Kentucky 40201 [C. E. K. E. E. 0., J. K.. K. L C.. ft. W./, end me Oeeertment ol BtCClmeetPy. Cencmr Peieetck Unt. CeUege o/ <<bcinu. Howard Unteemty. Wstktngton, 0. C. (H, P. M.)
abstract
MATERIALS ANO METHODS
The purpoee of this investigation was to evaluate the gfycosaminoglycans (GAG's) in different behavioral-histeiogieal types of i.m.-transplanted hepatomas and in the liver and urine of animals bearing these tumors. Groups of 10 Buffalo rats carrying fast-growing (7777), intermediate (5123tc), and slowgrowing (9618A) Morris hepatomas were studied as the tumors reached 3 cm. Urinary and tissue GAG'S were isolated by proteolysis, separated as cetylpyridinium complexes, and measured as uronic acid. The GAG'S were further purified using anion-exchange chromatography and characterized with mucopolysaccharidoses. Tissue GAG's were also evaluated histochemically using Aldan blue staining and mucopolysac charidoses. Tissue from fast-growing, intermediate, and slowgrowing tumors exhibited greater GAG levels than did normal liver in the hyaluronic add (0.4 m NaCl-eoiuble) fraction and in the chondroitin sulfate-heparan sulfate 0.2 m NaCi-soluble) fraction. The livers of tumor-bearing animals exhibited GAG levels similar to those of normal liver, increased urinary GAG excretion was appreciated in animals bearing Tumors 5l23tc and 9618A but not in those bearing Tumor 7777.
INTRODUCTION
An increasing number of reports cite the presence of com paratively high levels of GAG's* in both animal tumors (4, 7. 18, 22) and human tumors (5, 12, 16). There also have been reports citing qualitatively and quantitatively abnormal urinary GAG excretion in association with malignant tumors (6,10,11. 23-25). Although there have been attempts to establish any functional relationship between tumor GAG's and tumor ceil properties (23, 25-27, 30, 31), the significance of elevated GAG's in malignant tumors remains obscure.
In view of the possibility that GAG's play an important role in the expression of one or more malignant ceil properties, our purpose here was to evaluate the GAG patterns associated with transplantable hepatomas exhibiting different growth rates and metastatic properties. Because it has been suggested that tumor GAG may be contributed by normal host tissue in re sponse to the presence of hepatic tumor (7), a secondary purpose was to evaluate the influence, if any, of "remote" hepatomas on the GAG's of the host Hvec a third purpose was to evaluate the urinary GAG patterns in hepatoma-bearing animals.
' Sucoortud by American Cancar Sodary Qrant IN-n 18. by a gram bom mo Manufacturing CMmliia Aaaocraticn. and m part by USPH3 Oranta CA 10729 and CA 24*201.
1 Praaani addraaa. SMroqlcal Sdancaa. Murray State UntveraMy. Murray, Ky. 42071. To whom raouaati tor raertnta mould be addroaaed.
* The abMMabon uaed to GAO. otyccaanunoglycan. Received Acr* it. 1990: accepted October 24. tseo.
Materiel*. Hyaluronic add (umbilical cord) was purchased from Nutritional Biochemical Corp. (Cleveland. Ohio); chondrdtin sulfate (whale and shark cartilage) and sodium heparin were purchased from Sigma Chemical Co. (St. Louis. Mo.). Authentic samples of heparin, chondroitin 4-sulfate, heparan sulfate, and hyaluronate ware also kindly supplied by Dr. M. B.
Matthews. University of Chicago. Bovine testicular hyaiuroddase was purchased from ICN Pharmaceuticals (Cleveland, Ohio), Streptomycea hyaluronidasa was obtained from Calbtochem (La Jolla, Calif.), and Proteus vulgaris chondroitinsae ABC was purchased from Sigma.
Experimental Design. Forty male Buffalo rata wars shipped from Lab Supply Company (Indianapolis. Ind.) to Washington, 0. C.. where 10 ware inoculated bilaterally (thigh) with Tumor 7777, 10 ware inoculated with Tumor 5l23tc, and to were inoculated with Tumor 961SA. These ware shipped to Louisville with 10 controls. Throughout the study, animals wart provided free access to food and water even when placed in metabolic cages for urine collections.
Urine collections were made twice each week from animals bearing Tumor 7777 and ones each week from animats bearing
Tumors 5123tc and 9818A. Collections were made alterna tively on one-hart of the animals in each group, with 5 control animal collections made each time a collection was made from tumor-bearing animals.
Tumors. Line 5123tc is a tissue culture variant of a moder ately differentiated trabecular hepatocellular carcinoma in duced with dietary administration of Af-2-fluorenyfphthalamic acid. Tumors wars received and studied here in the 165th generation.
Tumor line 7777 is a poorty differentiated hepatocellular carcinoma induced by dietary administration of N-2ftuorsnyiphthalamic add. This lint waa studied in the 159th transplant generation.
Tumor line 9618A is a well-differentiated hepatocellular car cinoma induced by 2-(4'-methyl)benzoyiaminofluorene. This tumor was studied in the 13th generation.
Characteristics of those 3 tumors observed in our laboratory and selected characteristics reported by Hruban et at. (13.14) are summarized in Table 1 (aee also Fig. t).
Extraction and Purification of GAG's from Liver and Tumor
Tissue. Dry defatted tissue was subiected to proteolysis, tri chloroacetic acid precipitation, and dialysis, and the GAG's were separated at cetyipyridinium chloride complexes into 0.03 m NaCt-aoiuble, 0.4 m NaCt-soiuble. 1.2 m NaCt-sokibte. and 2.1 m NaCI-soJubie fractions as described by Schiller at ml. (28) and measured as uronic acid (aae Schiller et el.) by the carbazole method of Bitter and Muir (1).
FEBRUARY 1981
CMA 003173
419
C. . KupchUm er si.
Ttanor Hn*
7777
Qrowtii raw doatgnaBon
Fast
Table 1 Cfieracrarfitics of (tie tranaptanraBto AaeaMmaa atummi
Tima (day*) until tumor raacIwdS. cm-tonq aw*
Mataatatic Oanaral mataotatie ebarHtwotogypotential* actortottc oBaorwd bar* CoSason*
16
Poorly diftaran-
+ + +
Scattered lung mcro.
ttatad
mataataaea but no
+
5123tc tntarmaolat* 9618A Slow
38 Modarataty dtttarantiatad
Aceordkig to ttw data of HruBan ar af. 04).
+ + MultlcW large mataataaaa to kings greaaty evident in lung* oI ati
0 ^tdamt^Mmoing
o
0
Anion-Exchange Chromatography. Following uranic add measurement, the uranic add-positive material was pooled by tumor line with tumor and liver tissue material pooled sepa rately. The cetytpyridinium chloride was removed as described by Korn (17), and then each fraction was dialyzed and sub jected to Dowex 1-X2 (200 to 400 mesh) anton-exchange chromatography as described by Schiller ef a/. (28). The 0.0,
0.5,1.0,1.25.1.5, and 2.0 m NaCI eluate fractions were eluted stepwise in 15 to 30 fractions (10 ml) each. One-mi samples were assayed for uranic add to produce an elution profile. Chromatographic fractions were pooled across all tissue groups, dialyzed, and concentrated, yielding 6 pooled fractions which were then subjected to enzymatic characterization.
Enzymatic Characterization. Each of the fractions were subjected to digestion by Straptomyees hyaluronidasa (digests only hyaluronic add), bovine testicular hyaluronidaae (digests hyaluronic add, chondroitin, and chondroitin sulfate but not heparin, dermatan sulfate, or heparan sulfate), and chondroitfnase ABC (digests hyaluronic add, chondroitin, chondroitin
sulfate, and derma sulfate but not heparin or heparan sulfate) as described by Kojima ef a/. (18).
Histochemistry. Small pieces of liver and tumor as wen as lung and intestine in selected animals were fixed in Zenker's fluid, embedded in paraffin, cut at 6 pm. and subjected to hematoxylin and eoain, Aldan blue-periodic add-Schlff (21), and Masson's trichrame (21) staining. Aldan blue-periodic add-Schiff staining was also carried out with and without prior digestion in chondroitinase ABC and bovine testicular hyaluranidase (9). For the condroitinaae ABC study, hydrated tissue sections were incubated with enzyme (18) tor 2 hr at 37*; control sections were incubated in buffer only.
Statistical Analysis. Statistical analysis of tissue GAG data was carried out in a sequential format starting with an analysis of variance. Significant differences among the means were further evaluated using the Newman-Keuls procedure de scribed by Snedecor and Cochran (29).
Uranic add levels in the 0.04 m NaCI fraction isolated from the 3 tumors were similar and significantly higher (p < 0.05) than the levels found in normal liver. In the 1.2 m NaCI fraction, tumors exhibited 5- to 8-foid greater (p < 0.05) uranic add levels than normal liver. In the 2.1 m NaCI fraction, uranic add levels were similar tor all tissues except that Tumor 9618A had significantly higher (p < 0.05) levels than did Tumor 5123tc.
There was a statistically significantly greater (p < 0.05) level of uranic add in the 0.03 m NaCI fraction tar the fivers of animals bearing Tumor 8123te compared to normal liver and the livers of animals bearing the other 2 tinea. Except for this, differences among livers were unremarkable.
toon
RESULTS
The amounts of GAG in Tumors 7777, 5l23tc, and 9618A and in normal liver are presented by fractions in Chart 1. "Uranic acid" levels in the 0.03 m NaCI fraction were similar in Tumors 7777 and 5l23tc but were significantly (p < 0.05) lower than the levels found in tumor 9618A and in normal liver.
420
rsanss------ sanao------ rsras-------rnaras
Fraction la vtialt M*rftiatiti*a ortiMa Katie ie MtiM* Clwtl. OSQ UmKunaaiimtaeunimc add In Hal grain in* (FI Timor 7777. liiWnwaitiaaa i*M (0 Tumor 3123m. and stow wwmg (3) Tumor M18A and M ttia arum o< non Banqr Beams <70 awimali ter eecS ct 4 aaquontiatiy Gotiactad aati traction*. Sam, saomoarlo mean*. OMaraneoa Bowman HI and 3/M In ttw 0.03 m Nad fraction. Bawnon aanor tiaaue and normal Mf m Bom aw O.a M and 1.2 m Nad fraction. md Bom aan I and 3 In m* 2.1 w Nad fraction am aiadaticatiy atswncam (p < O.Oti).
CANCER RESEARCH VOL. 41
oo3n4
Chromatograohie d2ta tor the 0.4 m NaG and l -2 m NaCI GAG fractions, thcss !rac;ions which ware appreciably larger in tumor tissue versus normal liver, are presented in Chart 2
together w;:n the ;a;:arns obtained for these same fractions .so'ared from normal liver and :i-,a uver of iumor-oeanr.g anirra-s These data .ndioate that, oven thougn the uronc levels
`we o-t a: "'oot.or.o were similar from lumor line to tumor line, there viera some qualitative GAG differences in the fractions isolated from different tumor lines. This is even more apparent in eompoatte Chart 3. which was derived by multiplying the mean of the individual uronic acid levels shown in Chart i by the percentage of distribution shown in Chart 2 and then summing within each chromatographic fraction.
I 1M'J1
:_____II
i
ICO-
l
3
3AG'S ifi Morns Hopo'zr'oo A
c
Enzymatic Characterization of Tumor GAG'S
The results of the enzymatic characterization of GAG's iso lated from tumor tissue are summarized in Table 2. On the basis of the elution patterns reported by Kao and Leslie (i S) and corroborated in our own study of authentic GAG's and on the enzyme susceptibilities for each fraction given in Table 2, w# arrived at the identities of the predominant GAG in each chromatographic fraction given in Table 2, Column 7.
Hiatochemicai Observations
A 100 0
100-
0
Tumors. Each of the 3 tumor types exhibited significantly more intense Alcian blue staining than did normal liver or host liver; GAG's were generally distributed throughout the tumor tissue. Tumor sections subjected to hyakironidase or to chon-
0.4M NCt,
idMNaCi,
HjO OSM 10M 1.23M ISM 2 0M Anion tacnang* column NaCI fraction*
Chart 3. Anion aacnmgo cftramongrapMe oattoma atxiad tor nta OAO'i
cMortta comptaaaa A, Tumor 7777: M. Tianor S1231c C, Timor 90ISA; D.
Dvora of flaaor-ooomg ananala POOMd acrooa kjaior tygac , Himto aw. Ttuo
chart m a camuoaMa of Owns l and 2 md m OaaaO on rta oawaniayaa (gtwi m Chart 2J oftM anmmaao aw of ttw erthiMurt worts aeM wfun <gfwi m
Chart i] tor aoch Oaaua ryea Oy McCrt-
SO
SO.
io
droitinase ABC exhibited reduced levels of Alcian blue staining consistent with biochemical measurements and the enzymatic
characterization of chemically isolated fractions. Hoet Livers. The livers of animals bearing Tumors 7777 end
9618A were histotogicaity indistinguishable from normal liver. Liver tissue from animals bearing Tumor 5123tc consistently exhibited a slightly greater vacuolar appearance than did nor mal liver (Fig. 18).
5*0 bJLl
0
Mm
II
111
HjO Q.5M 1 OM HjO OlSM 1 OM 1 j9M I SM 2PM Amen aachango cohawn NaCI fraction*
2. anton aaaww
Mogr^htc rtortaa tot tha OAQ-ctywynoa*
Mrta*r at 0.4 w and i .2 u NaCI. A. Tumor
7777: 9. Tumor 5123*c; C. Tianor geiSA: 0. MOMS aw ttaauo Mm nmr>
: E. normal aw. nawartaa rangao Mm BS to 107%.
Urinary GAG Excretion
Over the entire study, mean total uronic add excreted per pair of animals per 24 hr for control animals and animals bearing Tumors 7777. 5l23tc, and 96ISA ware 118 * 7 (S.E.), 118 3.203 12. and 201 7/g. reapectivety. GAG excretion by animals bearing Tumors 5123tc and 9618A were statistically significantly (p < 0.08) aievatad over controls and animals bearing Tumor 7777. There were 22, 8, 8, and 27 twenty-four-hr collections assayed, reapectivety. The smalt number of 7777 and 5123tc samples was due to me rapid growth of these tumors and time in transit after inoculation.
Urinary excretion profiles for animals bearing Tumor 5123tc over time and in relation to tumor size are illustrated in Chart 4. A similar pattern over a longer time span was observed in animals bearing Tumor 9618A. In both 5123tc and 9618Abearing animats, uronic add excretion appeared to be greater after the tumors reached larger sizes, but no regression with tumor size was apparent in either case.
FEBRUARY 1981
CMA 003175
421
4
C. E. Kupchmtta atat.
TabW2 WWWceaon or me prwuammam QAQ m each or our nwiHnwg.---------- g The tderWSeatton (CMww 7) or the predomftant OAQ of QAQ'i oresent m each of our amon-exchange 1) waa deduced bam (a) aotabteea of catytayndlntam chloride comptese*. (6) amon-exchange chromatographic dial wa obtained tar aulhenPc OAQ * and tnoee raponad by Kao and Lesha (i 5) (Columns 2 and 3), and (c> nw
(Column "
tonWiiisiana
of each traction
Downs 1-X2 traction (u
NaCl)
QAQ'a rsporiad by Kao and Lata# 05) to m primarily atalad m ova traction
0.0
o.s
1.0 1.2S 1.5
2.0
Hyaluronic add (84)*
IHown
(78)
Chonwolsn 4-auttata
(SS)
CtandroMn e-auttaw
(S3)
Hap*rin<72>
* ILi^luaa * iiaaaaiMkaaaB
Other GAG s reported to M partially eluted m
this traction
Non*
Hyatararac add (12) Heparan iiiMaM (14) Heparin (18) Oarmatan sultala
(IS) ChondroMn S-miMala
(IS) Oarmatan luttais
(67) Ctwndrattan 4-au-
lata (13)
aj digested by Streptomycet hyaturondaaa
70-100 35-61
0 0
30
0
% digested by bovine testic ular hyataroro-
daaa 80-100
61 0 <2
25
?
% digested by cbondront-
nase ABC
to7o
0 0
22
0
Predominant QAQ ei out traction
Hyaluronic add Hyatararac acid H*pwt Heparan auttata
Heparan suited and/or heparin
Haparin
Chart 4. Urinary QAQ aawaftan In rotation to tumor growth tar anfaiata ban mg Tumor SI 23tt and in eemroi antawta. #, tumor-bearing anbnata; O. control ananafa.
Wa had sufficient urinary QAQ's for anion-exchange chro matography only in tha eaaa of control ammala and animals bearing Tumor 9618A. A chromatographic comparison of these 2 profiles indicated that tha elevation in urinary GAGs occurred across alt column fractions to about tha same degree.
DISCUSSION
Tha results depicted in Charts 1 to 3 conform to tha gener alization (7, 16, 18) that tumors, including hepatic tumors, exhibit high levels of QAQ's relative to the tissue of origin. Charts 2 and 3 suggest that differences between tumors may be related to the behavioral properties of the tumors. Chart 3 reveals a gradation from normal liver, through the liver of tumor bearing animals, well-differentiated. slowly growing tumor tis-
sue to faster-growing, metastatic tumor lines. The gradation shown in Chart 3 is even more striking if the patterns for tumor
lines 7777 and 5123tc are inverted. Since tumor line 51231c waa more highly metaatic than waa Una 7777 (Table 1), such an inversion would arrange the tissues according to metastatic potential and raises the possibility that the patterns, particularly Fraction 1.0 m, are related in some way to metastatic potential.
It is postulated that the 1.0 m NaCl chromatographic fraction contains an undersuMated form of heparan sulfate such as that described by Kuroda ot at. (18) in AH109 hepatomas. Both Kuroda ef a/. (18) and Salto (25) reported that heparan sulfate is the major GAG constitutent in AH109A hepatic tumors. Kuroda at at. also reported that most of this heparan sulfate is eluted in 1.0 m NaCl in anion-exchange chromatography and that heparan sulfate is also the predominant GAG in normal liver and suggested that this may mean that the tumor heparan sulfate cornea from tumor cells and not from connective tissue elements within the tumors.
The predominance of heparan sulfate in Morris hepatomas and in AHIOWA hepatomas do not conform with the fact that hyaluronic acid and chondrortin sulfate have generally been identified as the predominant QAQ's in animal tumors (4, 7). These findings likewise do not conform with the report by Kojima at at. (16) that chondroWn sulfate and hyaluronic acid are the predominant QAQ's in human hepatocellular cancer.
The poesibility that tumor heparan sulfate is related in some direct way to tumor behavior has been raised by others. A role for sulfated QAQ's in cell recognition and adhesion has been proposed by Dietrich at at. (8). and Chiarugi and Vannucchi (3) have proposed that call surface heparan sulfate regulates both ceil division and transport.
The histological appearance of the tumors studied here end
the histological normalcy of the livers of tumor-bearing animals agree with the findings reported by Hruban ef at. (i 4). Although the vacuolar appearance of the livers of animals bearing Tumor 5123tc is not abnormal in rodents, this characteristic was uniformly present in all Tumor 5123tc-bearing animals and was found in no Others. The possibility exists that this structural feature is related to the high concentrations of the uncharac-
422 CANCER RESEARCH VOL. 41
CMA 003176
V2rr73
ter-Q&d. 0.C3 .'.: NaCI-soluDte. urortic acid-posinye-matenal `' --i ,,-j '-ieA i;v-^S
~*i9 tact that urina"/ GAG excretion was elevated in animals
Wmm -- T .-*,-*.** 5 ^ ^ * C
'rj* *> *
-3 r ^
C.aincn 3 9 -2C2;i`',i^r a: j
L. 0*. fsiace. O. M S , ana Cassaro. 3, M 7 C,..i
- si via a ccs-;c:t?
trr.. tu-t or :nn
:
1977 1..'Ai J.-s 3*ccn:.-7i 3.:,,.../-,. .3-s. Co--.--.'.,. /j Ct
Cfu"/. 9 i 3 tnd'.Valiinqrsn E Cj.-s.~n y
u : jh 'i '! sx ii.j7
7 .xrni.-yj,- 20
z'-V'r` -:s ?* a?'*" n mj-ic'S *,'d 'S not simply an 'nd-rs-ct rejyi!
: i - - - 1--'~>
'ev? s c* e.'o*ret, 3'" >: f 3AG
m our cantroi ana experimental animals agree witn ieveis
reported tor rats by Lehtoneit af at. (1 Si
lt remains to be determined wtiat the source(s) of the elevated
urinary GAG is (are). There have been reports Of striking
increases m GAG synthesis in tumor cells (see Ref. 20). but
Kojima et at. (i 6) have suggested that decreased degradation
may account for increased GAG in some tumors. Our investi
gations provide no evidence that the source of the abnormal
GAG increases in tumor tissue and urine is anything other than
the tumor cells themselves: however, a possibility that these
results stem from an impaired ability of the liver to degrade
circulating GAG'S cannot be ruled out.
V* IWW^WtWIl
Our data clearly show that hepatomas 7777. 5i23tc. and 9618A have GAG compositions that are appreciably different than tnat of normal liver. These data show that there are also Qualitative differences in GAG between tumor lines and that heparan sulfate patterns parallel growth rate and possible degree of malignancy. Heparan suifate is the predominant GAG in the hepatomas studied. The increased unnary excretion of GAG's for 2 of the 3 tumor lines examined suggests that unnary GAG analysis may prova useful in the detection and diagnosis of some hepatic tumors.
REFERENCES
i Bitlw. T. and Muir. H. A modified urnnte acid carbueta reaction. anal.
axxMn . * 330-334. I9S2. 2. Camaron. .. and Pauling. L. AaeorMc acid and m# ^ycoeamnogiycans.
Oncology(BaMO27. 181-192. 1973s
3. Cnwrugt. v. p.. and vannucct*. S. Surraca Hacaran auMate aa a central
ament in auftanottc ea*r a working mod*. 4. Thodr. Voi.. St: 4S9-47S.
1975
4. Owl. h. V.. Moyer. X., and Swann, R. MucnpoiysracHonira and DTOtam-
poiyseccnande ot a nanacMnueW rat rhondreaarrnma. Proe. No*. Acad. Sci. U. S. A.. Si.' 577-579. 1971. 5. Cudkomez. a The pctyeocenandee at a Human caramoma. Br. J. Cancer. 10. 759-753. 1955. 5. Curran. K. I_, KupcfteNa, C. t. and Tamourra. C. M. unnary grrcoaammo gtycan oattama in angmaatcdme at the War. Cancar (Pttua.), 40: 30603053. 1977 7. Oatmnetsky. i.. OpoanhaMwr. K. T.. I tanner Wmama. O.. and wwate, m.
l m ram* npnora. Cancar Ran.. 2S. 229-232. 1955.
'. : -?; -smi'.-mr- ^ ;"s if ;n- i..tnr-i:30'r:,iC irC 'ymonafji; ry.vi-i; Ar:.s M./t
a v 7,1m--1 , j?e ..s" jn 7 Aui :i...ui'iiio:"2
nymagiomucsij wiin cutaneous, neeanc and axaWiat manitestations ana rerrisaa urr-aty exerenonof g'yeosaminogiyeans. Acta Vd Seand., !3S 525-530. 1975 12. Mina, v . Yoda. Y,, and Makna. A Glycosammogiyeint in smaa can carcinoma et Human lung: Histologically diaracwnsnc pattern. Gann. 70: 359-390. 1979 '3 Mnj^an Z xioeniiuki V. Slasari A. ana uo-n MPA COI--ci-xr-y
study at ceikilar organatta* at Morns haeatomaa. Cancar Rea.. 32: 843867. 1972. 1 a Mrudan, Z.. Moms, H. P., Mocmaukt. Y.. Maranaa. 0. R.. and Slasars. A. Light microscopic eosarvationa at Morn* heMiemaa. Cancer Rea.. 3 / 752752. 1971
15. Kao. K. Y. T.. and Laala. J. G. Microtractiooatlon and Hatermination of urinary gtycoaammagtycan*. Bdcnam. Mad.. 9. 317-325. 197*.
IS. Koiima, J.. Nakamura, N,, Kanatam. M., and Otunon. K. Tha glycoaamtnojlyean* in Human nedalie cancar. Cancar Ra*., 35. 542-547. 1975.
17. Korn. . 0. TH# isolation et heoann from mouse m*s can tumor J. eiot,
Cnnm.. 2jd 1325-1329. '959.
15. K-rsca, 5.. Saito. S.. Sane, N.. Nagaae. S.. and Anno. K. isolation and cnamical cHaractanzaaon ot mucoootyiaccnandaa tram rat tumors. Cancar Pas.. 34 308-312, 1974.
19. LaMonen, A.. Nanto, V., and Kasanan. A. THa attacts at some sntunHam-
mslory agents on tna urinary axcrapcn ot mucopotyaacctianda* in tna rat Ann. Mao. exp.; Fan., 45. 32-34. 1957. 20. Manley. Q.. Sowar.!_ and Anson. A. Unnary axcraoon at gtycoaamnogtycans m sissammatad naoclasm J. C-ln. Pithd.. 31 447-453. 1973.
21. McManua. J. F. A., and Mowry. R. W. Stammg Maitioda- Histotogiee and HtatoenemtcaL Naw Yqrx: Paul S. Hoaear. :nc. (Marpar and Brothers). 1950.
22 Nakamura, n.. Muri. Y.. Tamgatu. Y,, and Koyma. J. Changes m tna caktav
giycosamategiycana ot euHurad mastocytoma ceM mduead by sodium bu tyrate. Biocnim Biopnya. Ado 627: 50-70. I960.
23. OnMo, L.. and Seaar. F. 0. The mucopolyiaccnandM si me normal and aiiaiaad oraast: ttiwr aatnoutton and wgmiicanca. Am. 4. Padtok, 34- 993-
1009. 1945. 24. Rich. C.. and Moyers. W. P L. Bacradon at add mucaootyiacehandn ai
me unna at panama wan inaPgnam naepmade dlaaaaaa. J. Lab. On. Mad. 54 223-225. 1949. 25. Sarto. S. MucopotyaacawndM ot rat aaotas Haoaaoma ** Gantt. 44 247-254, 1973. 26. SattaM, T., Tsurum. N.. Maado, J.. and Marsuda. h. Studiea on tna mauancaa ot text murixtotysacrnarioas on me gtowm at Tawo sarcoma. 4. Osaka Dental Urn*.. 4: 113-122. 1970.
27. Sanders. F. K.. and Smtw. 4. Illact ot rroiagan and aod tkitysaccnartdaa on the stowdt ct BHK/21 caisanami acid madia. Naaee (Lana.). 337 513-
515. 1970. 25. Sctxaor. S.. Stoner. 0. A., and Oottman. A A method tar the aoparabon at
text muceoolysaccftartde*: 1001*001100 to mo iseioitan at Hopann (ram mo asm ot rat*. 4. BUI. Cham.. 235 943-957. 1951. 29. Snodaccr. G. W,, mid Cochran. W. G. StaMaflcM Mameda. Ed. 6. o. 273. Amaa. Iowa; lowa Sura Umramty Praas. 1957. 30. Takauctii. 4. Growth utomowng ettact ot amd mueooolyaacchandaa on EhrSch aacilaa tumor. Cancar Rea.. 26: 797-402. 1955. 31. Wkitarooume. 0. 4., and Mora. P. T. Ostrounan ot gtycocomugaMa m moura IHwcCrasra wdh yarpng day111 ot ttanonpaferty. 4, SuoramoL smict- 7. 91-100. 1977.
QO^rP
cv^
FEBRUARY 1981
423
C. . KupcftcM f a/.
wiM Maine* tat am a# Ita
haMw Tumt
CMA 003178
CANCER RESEARCH VOL. 41
EPA 560/6-81-002
9
fcrIUtMIQLGGY STUDIES SCREENING FOR THE EARLY DETECTION OF DISEASE
IN INDIVIDUALS EXPOSED TO VINYL CHLORIDE
JANUARY 1981 FINAL REPORT
U.S. ENVIRONMENTAL PROTECTION AGENCY OFFICE OF PESTICIDES AND TOXIC SUBSTANCES WASHINGTON, O.C.
CMA 003119
EPA S60/6-81-002 January 1981
SCREENING FOR THE EARLY DETECTION OF DISEASE IN INDIVIDUALS EXPOSED TO VINYL CHLORIDE
Carlos H. Tamburro1 Charles Kupchella1 Kenneth Taylor^ Emanuel Landau^
Richard Greenberg1 2
Hildegarde Marlcq Joseph Whelan, Jr.1
Joseph Seifter
1. University of Louisville Louisville, Kentucky
2. University of South Carolina Charleston, South Carolina
3. Yale University New Haven, Connecticut
4. American Public Health Association Washington, D. C.
5. U.S. Environmental Protection Agency Washington, D. C.
Project Officer Jane Keller
Office of Pesticides and Toxic Substances Washington, D.C.
U.S ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460
CMA 003180
DISCLAIMER This project has been funded with Federal Funds from the Environmental Protection Agency under contract number 68-01-3859. The content of this publication does not necessarilyreflect the views or policies of the U.S. Environmental Protection Agency, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.
cv& 00311
ABSTRACT
A prospective collaborative study was conducted to compare the effectiveness of four clinical techniques in the detection of liver damage due to vinyl chloride monomer exposure. A chemically exposed and medically monitored worker population was identified by histopathological and biochemical docunentatlon. Three techniques were non-invasive: a) grey scale ultrasonography of the liver, b) microvascular skin capillary assessment, and c) urinary analysis of glyco-
QQ saminoglycan excretion. The fourth technique was the standard raTc sulfur colloid radionucleotide liver spleen scan. The screening studies were performed on a randomly selected single cohort of chemical workers; some of whom were known to have disease. All four techniques were analyzed for their sensitivity and specificity as compared to results of the liver biopsy and biochemical blood test classification. Although all four screening techniques had a sensitivity and specificity sun greater than one, none were significantly better than could be explained by chance or the use of a biased coin. Reclassification of the population Into those with more severe biochemical abnormalities Improved the sensitivity of all screening tests, but only the sensitivity and specificity sum. for the GAG test were statistically significant at the 0.05 level. There was no significant correlation between any pair of screening tests. None of the four screening tests agreed with the biopsy results better than might be obtained by biased coin or chance. These screening studies as presently constituted, do not provide sufficient sensitivity and specificity to warrant their use In comnunity screening for subclinical asymptomatic hepatic Injury due to chemical exposure.
CMA 003182
IMRCCUCTION
The Initial reports of primary liver cancers (angiosarcoma) in rats exposed to vinyl chloride by Maltoni, et al (1) and the discovery of similar liver tumors
/
in vinyl chloride polymerization workers by Johnson and Creech (2) has lead to considerable environmental concern regarding comnunities surrounding chemical industries which utilize potentially carcinogenic agents such as vinyl chloride. Several investigators have reported on various screening techniques as effective indicators of vinyl chloride chemical injury. Four such techniques - ultrasono graphy (3), radionucleotide scanning (4), nailbed capillary visualization (5), and glycosaminoglycan (GAG) (6) excretion - were reported to have seme possible usefulness in detecting early chemical injury to the liver. In order to determine the useability of these techniques for community screening, the American Public Health Association (APHA) and Environmental Protection Agency (EPA) funded a multi-center collaborative study designed to determine the comparative sensitivity and specificity of these various techniques in detecting and identifying chemical related hepatic injury in asymptomatic Individuals. Materials and Methods
Population Selection The chemical worker population consisted of 1,178 active (Group B, Figure 1) employees as of September 1, 1977, and 70 employees who had had liver biopsies regardless of current employment status (Group A, Figure 1); they were undergoing annual medical screening for the idertification of work-related disorders. Th medical screening consisted of an annual or semi-annual (for those employees with 10 or more years of employment) comprehensive history and physical examinati." is, laboratory screening studies consisting of 35 biochemical tests, chest and abdomi nal X-rays, and radionucleotide liver-spleen scan.
CMA 003183
2
This population was selected for the collaborative study to determine the comparative effectiveness of four screening techniques in detecting liver damage as indicated by 1) past histopathological documentation of liver Injury of 2) current hepatic dysfunction identified biochemically.
Three of the four techniques were included as potential non-invasive pro cedures suitable for determining the effects of vinyl chloride in a comnunity population. These included 1) grey scale ultrasonography of the liver as devel oped by Taylor and colleagues (7, 13, 14), 2) a nailbed skin capillary evaluation of the middle and dfstal phalanges of the fingers as developed by Maricq and associates (8), and 3) urinary analysis of glycosaminoglycan excretions (GAG) as published by Kupchella and associates (9).
The fourth method included for comparison purposes was the standard radio* qo
nucleotide liver-spleen scan utilizying mTc colloid and interpreted by Whelan and associates (10).
The non-invasive screening studies were performed during a single week on a group randomly selected from all chemical company employees. The workers were selected on the basis of complete medical and work data for 1976-1977, and all those employees who had investigative liver biopsies performed during the screening program (1974-1977). The selection process for these workers is illustrated in Figure 1. The biochemical data and radioisotopic scans were part of the routine medical surveillance system for the employees. The pathological data was based on the last or most recent liver biopsy (s) which were performed
/
for medical reasons, both related and not related to their work. Positive and negative results were determined as defined in Table 1 which list the technique, the evaluation or evaluators, and the criteria used. The employees targeted for examination were selected by simple random sampling from all available employees.
CMA 003184
One hundred and twenty cne of the targeted 170 emoloyees (71 percent) participated. Twenty six ceciir.so to particitete or could ~ct oe scheduled; 13 did not keep their scheduled appointment. After participation, nine employees were discovered to have been misclassified as biochemically abnormal. They had some biochemical abnormalities but not all (classified intermediate) and have been eliminated from the final analysis. Four biochemically abnormal individuals had abnormally low test values and they were included in the analysis. Liver Biopsies
Liver biopsies were performed by the transjugular technique (11) and pro vided two to five biopsies from various areas of the liver. In addition, some individuals had second biopsies performed by the percutaneous of wedge biopsy via mini-laparotomy procedures. Pathological data was recorded in a computerized format identifying all histological abnormalities in a semi-quantitative fashion. 81opsies were read without knowledge of the individual's medical history or chemical exposure by two pathologists and a hepatologist with extensive experience in hepatic chemical injury. All biopsies were classified as 1) normal, 2) abnormal, a) chemical injury, and b) non-chemical injury.
The non-biopsy groups were drawn from those currently employed, and based on biochemical liver "function tests" Individuals were sorted into positive, negative and indeterminate for hepatic disease. Only the positive and negative are included In this study.
The ultrasonic evaluation and its relative ability to identify hepatic damage due to vinyl chloride has been published elsewhere (3).
Microvascular techniques and the method of evaluation by Dr. Maricq and co-workers are also published in part (8).
The experimental work on GAG excretion in vinyl chloride workers and the techniques for differentiating the electrophoretic patterns in patients with
CM& 003185
4
angiosarcoma and connective tissue damage of the liver has been published else where (9). The effectiveness of radioisotopic (radionucleotide) scanning as a technique for identifying anatomical lesions in vinyl chloride workers is in preparation (12). Method of Analysis
The blopsled group and the non-biopsled (biochemical) group were analyzed Independently. For the biopsied group sensitivity and specificity were estimated for each screening test by assuming that the biopsy was correct. For the bio chemical group the biochemical classification was assumed to be correct. For each analysis the data consisted of a simple cross classification. In a perfect screening test, the sum of sensitivity and specificity would be two. In a screening test which provided results no better than could be obtained by using a biased coin, the sum of sensitivity and specificity would be equal to one. We, therefore, estimated 95S confidence limits for the sum of sensitivity and spec ificity and observed whether or not one is included within these limits. As a
y test of statistical significance this Is equivalent to the usual X test for Independent proportions.
Finally, In Table 4 we looked at the association (as measured by the phi coefficient) between each pair of screening tests. For these comparisons we used all employees who received both screening tests regardless of their biopsy status. In this case, we assumed both tests were subject to error and estimated the phi coefficient (r4) between them. Finally, for completeness, we give the biochemical classification for the 51 employees included In the biopsy group.
Results Table 2 compares the histological and biochemical results for the 51 biopsied employees Included In the study. Twenty-two of these employees had biochemical abnormalities as defined In Table 1. There was no significant
CMA 003186
ccr"s7>t'>n
the biochemical and biocsy c^assificaticn for t-? Zj
5"tiT'?s with positive cr relative biochemical classifications { i = 0,21; Xf =
0.20). The biochemical studies used in this analysis were those determined at
the time of this and not at the time the biopsy was.performed. In all instances
of disagreement, the biopsy was positive and the biochemical results negative
(P< 0.00T).
Figure 2 provides the sensitivity and specificity for each of the screening
tests when compared to biopsy results. In no case is the sum significantly
greater than one, indicating that the results are not statistically significantly
better than could be obtained using the biased coin. With the exception of the
GAG studies, similar results are obtained when comparing the sum of sensitivity
and specificity in the biochemical group (Figure 3). The sum of sensitivity and
specificity for the GAG studies are just statistically significant with 95 percent
confidence limits of 1.06 to 1.52. Table 3 gives the frequency distribution of
the results of the GAG test for employees with normal and abnormal biochemical
results. The distributions differ In their spread (variance) and not in their
location (means).
Finally, the correlation matrix for the four tests are given in Table 4.
There is no significant correlation, as measured by r$, between any pair of the
screening tests. This Is also true when they are sorted by biopsy status.
After reviewing the results, a reclassification of the 51 employees who had
biopsies was assessed in regard to whether there was chemically induced liver
damage. Ultrasonographic evaluation was reclassified by Dr, Taylor and the liver
biopsies by Ors. Tamburro and Popper. Table 5 gives the results of this additional
analysis which demonstrates that there was no agreement that could not be explained
by chance (P 0.60).
CMA 003187
6
Discussion
The Increasing Industrialization In highly developed Western countries, such
as the United States, continues to provide concern, not only for the health and
safety of the Industrial workers, but also for the surrounding comaunltles In the
areas of these Industries. It is highly desirable to Identify and validate the
reliability of screening and diagnostic techniques which will Identify the early
development of Injury due to the exposure of a variety of chemicals such as
vinyl chloride. The assessment of newly developing techniques on a high-risk,
exposed worker population, who have been carefully screened and prospectively
followed, provide the most reliable method for determlng both the sensitivity and
specificity of these technical procedures In the asymptomatic subcllnlcal high-
risk exposed community population. The failure of such techniques to provide
sufficient sensitivity in the presence of a required specificity Is of critical
clinical Importance. This Is especially so where the Incidence of disease Is
relatively low and the population exposed large. Tests which provide a high
sensitivity but of low specificity can and do medically stigmatize the population
under surveillance leading to unnecessary anxiety and socioeconomic disturbances
which can far outweigh the benefit of early detection of even serious disease In
a smaller population.
Far too often screening techniques which have been developed In a highly
diseased, clinically overt, hospitalized population are applied to an asymptomatic,
clinically well-working populations without adequate determination of the sensi
tivity and specificity at this earlier stage of disease development.
In this study, all four techniques had. In the highly diseased hospitalized
population, demonstrated either a sensitivity or specificity suggestive for the
Identification of underlying chemically related liver disease. Some techniques
(Marlcq and Kupchella) appeared Ideal for community studies since they were non-
Invaslve, relatively Inexpensive, and provided a means of screening which would b
highly accepted by a conmunlty.
CMA 003188
7
i prospectively das ion ad study has allowed us to estimate the ability of srssoncgraphy, nailbed capillary assessments, radioisotopic scanning, and glycosaminoglycan excretions to correctly predict the presence and absence of hepatic disease as documented by an exposed population. These studies clearly show that none of the four screening techniques sufficiently agree with either the biopsy, the biochemical results, or each other in a well defined population; they do not provide sufficient sensitivity or specificity to be useful as early indicators of chemical exposure Injury.
The inclusion of nine individuals with Intermediate biochemical results, who were originally misclassified as abnormal, would decrease the sum of sensi tivity and specificity in all three screening tests. With their exclusion only the GAG tests provided results better than might be expected by chance (P< 0.05); Even the GAGs, from a pragmatic point of view, provide too high a false positive rate to be useful in its present stage. Possibly, with increased refinement and further study, this might provide a simple non-invasive technique for the Identification of increased collagen changes related to chemical injury. More Imnedlately, it should be duplicated to rule out chance.
Had we eliminated the four employees with an abnormally low biochemical test values, the sum of sensitivity and specificity for the GAGs and nailbed skin capillary screening tests would have been slightly reduced and that for the scan slightly Increased. The GAG would still be of bordering significant (xf * 3.73), and the scan not significant (x| 1.46).
Finally, the tests not only disagree with each other, but within the biopsy group there was no agreement between the biopsies and biochemical results. It should be noted, however, that the biochemical studies used in analysis were those chronologically closest to September, 1977, and not to the date of biopsy.
CMA 003189
8
The test determinations and the biopsies may have been as long as three years apart. An analysis of the biochemical tests value done at the time of the biopsy would have more accurrately reflected the liver status, as shown by histology (15). It has been shown. In previously published studies, that biochemical and histological findings each correlate with chemical Injury and chemical exposure (16, 17).
CMA 003190
s
1. Maltoni, C. and Lefemine, G. Carcinogenicity to bioassays of vinyl chloride
I. Research plan and early results. Environmental Perpectives, 7:387-405, 1974.
2. Creech, J. L. and Johnson, M. N. Angiosarcoma of the liver in the manufac
ture of polyvinyl chloride. Journal of Occupational Medicine, 16:150-151,
1974.
"
3. Taylor, K. J. W., Williams, D. M. J., Smith, P. M. and Dach, B. W. Grey scale ultrasonography for monitoring industrial exposure to hepatotoxic
agents. Lancet, 1:1222-1224, 1975.
4. Whelan, J. G. Jr., Creech, J. L. and Tamburro, C. H. Angiographic and iso topic characteristics of hepatic angiosarcoma found in vinyl chloride workers. Radiology, 118:549-557, March 1976.
5. Maricq, H. R., Johnson, M. N., Whitstone, C. L. and LeRoy, E. C. Capillary
abnormalities in polyvinyl chloride production workers. JAMA, 236, 1368-
1371, 1976.
-----
6. Kupchella, C. E. and Tamburro, C. H. Urinary and tissue glycosanrinoglycan patterns in angiosarcoma and other vinyl chloride exposure - associated liver injury. In Prevention and Detection of Cancer, Part I, 1:915-926, ed. Niebergs, H., Marcel Dekker, Inc., 1977.
7. Taylor, K. J. W., Carpenter, D. A., Hill, C. R. and McCready, V. R. Grey scale ultrasound imaging the anatomy and pathology of the liver. Radiology, 119:
415-423, 1976.
8. Maricq, H. R. and LeRoy, E. C. Patterns of finger capillary abnormalities
in connective tissue disease by wide field microscopy arthritis pheum, 16:
619-629, 1973.
"
9. Curran, K. L., Kupchella, C. E. and Tamburro, C. H. Urinary glycosaminoglycan patterns in angiosarcoma of the liver. Cancer, 40:3050-3053, 1977.
10. Whelan, J. G. Jr., Greenberg, R. and Tanburro, C. H. The effectiveness, of radioisotopic scans and grey scale ultrasonography in. the detection of liver damage. Gastroenterology, 79:1129, 1980.
11. Rosch, J., Antonovic, R. and Dotter, C.T. Transjugular approach to the liver, biliary system and portal circulation. American Journal of Roentgenology, 125:602-608, 1975.
12. Whelan, J. G. Jr., Creech, J. L. and Tanburro, C. H. Primary liver cancer detection in vinyl chloride workers by radioisotopic scanning (In Preparation).
13. Taylor, K. J. W, Glees,J. P., Smith, T. A. and Carpenter, D. A. Ultrasonic examination of the liver. In Ultrasound in Medicine, Vol. pp. 173-174 (Eds.) White, 0. N. and Barnes, R., Plenum Press, New York, 1976.
CMA 003191
10
14. Taylor, K. J. W. and Carpenter, D. A. Comparison of radioisotopic and ultra
sound examination In the Investigation of hepatobiliary disease. In Ultra-
sound in Medicine. Vol. 1, pp. 159-167 (Ed.) White, D. N., Plenum Press,
hew Vorlt, 1576.
~~
15. Clarmont, R.J. and Chalmers, T.C. The transanilnase tests in liver disease. Medicine, 46:197-207, 1967.
16. Tamburro, C.H. and Greenberg, R. Effectiveness of federally-required medical laboratory screening in the detection of chemical liver injury. Environmental Perspectives, 1980. In Press.
17. Tamburro, C.H. and Greenberg, R.A. Identification of human toxicity and carcinogenicity by ethylene derivatives in mechanisms of toxicology and hazard evaluation (eds. Holmstedt, 8., et al) Elsevler/North-Holland Biomedical Press, New York, New York, pp. 319-334, 1980.
18. Tamburro, C.H., Makk, L. and Popper, H. Early hepatic histological alterations among chemical (vinyl monomer) workers. Gastroenterology, 77:A43, 1979.
CMA 003192
TalP^
CLASSIFICATION Biopsy
Biochemical
Ultrasound Microvar.cular
DETERMINED BY
CRITERIA
1) Dr. Popper, Pathologist
a) Positive by consensus agreement if medically significant pathology
2) Dr. Makk, Pathologist
is present. Negative otherwise.
3) Dr. Tamburro, Hepatologist
b) Pathology is of chemical or non
chemical origin. (18)
Liver "Function" Tests
Group 1
Group i
SGPT
GGTP
ICG
BILIRUBIN
SGOT
ALK. PHOSPHATASE
Positive if two or more Group tests were abnormal or if one Group 1 and both Group 2 tests were abnormal. Negative if all six tests were normal.
Intermediate otherwise.
Dr. Taylor
Defined as negative if the over all impression was normal. Posi tive otherwise.
Dr. Maricq
Defined as negative if there were no microvascular abnormalities. Positive otherwise.
Glycosaminoglycans
Uronic _ UG Uronlc Acid
nc*d
MG Creatinine
Defined as positive for values less than 2.0 or greater than 4.8. Negative otherwise.
Liver Scan
Dr. Whelan
Defined as positive if any patho logical defect was detected. Negative Otherwise.
CMA 003193
TABLE 2
COMPARISON OF BIOPSY AND BIOCHEMICAL DETERMINATIONS OF THE PRESENCE OF LIVER DISEASE
12
BIOPSY
BIOCHEMICAL POSITIVE 'NEGATIVE
SOM
BIOCHEMICAILY. TOTAL INDETERMINATE
POSITIVE NEGATIVE SUM
3 0 3
18 21 15 36
88
7 15
26 29 22 51
r - 0.20966
X? - 0.200 N.S.
*- 2
Matched xj - (18 ' l) /l8 - 16.1
P < 0.001
CMA 003194
FREQUENCY (F) AND RELATIVE FREQUENCY (R.F.) OF GAGS FOR NORMAL AND ABNORMAL EICCHEMICAL RESULTS
GAG
<2 2<3 3<4 4<5
5+
Sum Mean Variance
Normal
_________ Abnormal
a
R.F.
J.
R*F*
4 0.111 16 0.444 13 0.361
1 0.028 2 0.056
6 0.250 7 0.292 6 0.250 1 0.042 4 0.167
36 1.000 2.886 0.746
24 1.000 3.160 1.776
t " 0.968 N.S. T Test Independent Means s
F = 2.381 P < 0.05 F Test Independent
23,35
Variances ( Two Tailed)
CMA 003195
'1
14
TABLE 4
CORRELATION MATRIX (Bo) BETWEEN FOUR SCPEENIN3 'TVgffR USED TO PREDICT THE PRESENCE OR ABSENCE OF LIVER nTSRASR
GAG CAPILLARY ULTRASOUND RADIOISOTOPIC
ANALYSIS ASSESSMENT 'STUDY
SCAN
GAG ANALYSIS
* 0.08
-0.03
0.005
CAPILLARY ASSESSMENT (113)
0.03
0.07
ULTRASOUND STUDY
(87) (84)
* 0.06
RADIOISOTOPIC SCAN
(120)
(114)
(88)
None of the correlations are statistically significant (a = 0.05). The correlaticns are given above the diagonal. The sanple size is given in parenthesis belew the diagonal.
CMA 003196
I
15
TABLE 5
KECLftSSHTCATICN CF BIUPSltD U&WmS for cHEjccamr induced abndralitiis
Biopsy
Ultra Sound
Chemical Abnormality
Other
Chemical Abnormality
Other
7 26
5 13
SUM
33
18
SUM 12 39
51
Specificity * 13/39 0.333
Sensitivity * 7/12 0.583
Sun
TM 0.916
GROUP A
FIGURE 1
GRCUP B
16
*Not seen by Doctor Taylor
FIGU!
+OHj
0o) a
to
CdaJ
t'J *->
fO -r4
MH CH
to
\ 1
0
Nwbrrr fl;ployees IY>sit ive Biopsies Nej^il.lve Biopsies
SENSITIVITY AMD SPECIFICITY FOR FOUR SCREENING , TESTS FOR THE PREDICTION OF LIVER ABNORMALITIES
(AS DETERMINED BY BIOPSY)
GAG
(51) 36 15
Microvsscular Ultrasound
(49) 34 15
(51) 36 15
Scan
(51) 36 15
CMA 0 0 3 2 0 0
Figure 3
SENSITIVITY AND SPECIFICITY FOR FOUR SCREENING 00
TESTS FOR THE PREDICTION OF LIVER ABNORMALITIES
(AS DETERMINED BY REVIEWED BIOCHEMICAL TESTS)
1.29
Sum: Specificity plus sensitivity
16
95% Limits 1.15
Sensitivity
0
Nuriber Employees Positive Biochemical Negative Biochemical
Specificity
GAG
Microvascular Ultrasound Scan
(60) 24 36
(57) 22 35
(37)
(61) 24
37
STUDIES ON THE MUTAGENICITY OF VINYL CHLORIDE METABOLITES AND RELATED CHEMICALS
A. D. Laumbach, S. Lee, J. Wong, and U. N. Streips
Department of Microbiology and Immunology University of Louisville School of Medicine
Department of Chemistry Louisville, Kentucky 40201
I. INTRODUCTION
The studies by Viola et al (26) and Maltani et al (15) established the carcinogenic potential of vinyl chloride monomer. The detection of angiosarcoma in industrial workers exposed to polyvinyl chloride suggested a causal relationship between this chemical and the development of hepatic abnormalities (4,12). Hefner et al (7) have delineated the metabolic fate of inhaled vinyl chloride in rats and proposed that the epoxide, chlorooxirane, and chloroacetaldehyde were the carcinogenic intermediates. Their hypothesis has been supported by the work of several laboratories (3,14,16,19, Elmore, Wong, Laumbach and Streips, submitted for publication) using bacterial strains as mutagenic indicators.
In this communication we present additional data concerning the mutagenicity and the potential mechanisms of action of several vinyl chloride metabolites, including the previously unreported chloroacetadehyde monomer hydrate, chloroacetaldehyde dimer hydrate, and chloroacetaldehyde trimer. Eplchlorohydrin, a mutagenic/carcinogenic (21,25) methylene homolog of chlorooxirane was also examined.
II. PROCEDURES AND MATERIALS USED
A. Bacterial Strains
The bacterial strains utilised in these studies are presented in Table I. The Bacillus subtilis strains were all maintained on AK agar (BBL). Salmonella typhimurium cultures were obtained from B. N. Ames (l) and were stored on Nutrient Agar (Difco) plus 5g NaCl per liter.
003201
Laumbach, A.D., Lee, S., Wong, J., and Streipa, U.N.
B. Mutagenicity Assays
The indirect assay utilized repair deficient strains of B. subtilis. The procedure was a modification of the "rec-assay" describe? by Kada et al (9). Cells were grown overnight in Nutrient Broth (Difco) at 37C in a rotary incubator shaker, then diluted tenfold In phosphate buffer (pH 7.0). The suspended cultures were streaked onto Nutrient Agar plates (Difco). Filter paper discs (6 mm) were saturated with the chemical solutions to be examined, then were placed onto the agar plates next to the streaked bacterial cultures. Following incubation at 37C overnight the plates were examined and the lethality and mutagenic potential of the test chemicals were assessed by comparing inhibition zones between the B. subtilis 168 wild type, a repair-capable strain and the various DNA repair-deficient strains. In all these studies 4-nitroquinoline-l-oxide (4NQQ) was used as the positive mutagenic control.
Direct mutagenicity assays utilized the S. typhimurlum tester strains described by Ames (1). The chemicals were examined by the methods of McCann et al (16). The cultures were grown In Nutrient Broth plus 0.52 NaCl overnight in a rotary incubator shaker at 37C. A mixture of the test chemical (0.1 ml) in dimethyl sulfoxide (DM50) and 2 ml of soft agar (0.62 agar, 0.62 NaCl, 0.5 mM biotin, and 0.5 mM histidine) was added to 0.1 ml of the bacterial culture. The solutions were mixed thoroughly and overlaid onto minimil plates [Vogel-Bonner medium (27), 1.52 agar, and 22 glucose]. Control samples were prepared by omitting the test chemicala For the positive mutagenesis control, 4NQ0 was added to the mixtures in place of the test chemicals. All plates were incubated for 48 hr at J7C prior to the enumeration of revertant colonies.
C. Chemical Compounds
The chemical compounds utilized in these studies were prepared, purified, and analyzed by previously reported techniques (Elmore, Wong, Laumbach, and Strelps, submitted for publication).
D. Preparation of DNA
Transforming DNA was isolated from B. subtilis cultures by the method described by Young and Wilson (297* In some of the experiments the cultures were pretreated for 15 min either with chloroacetaldehyde (16 nM) or epichlorohydrin (16 mM) prior to the extraction procedure. In alternate experiments S-9 liver homogenate mix was added to the compounds prior to addition to bacteria. The S-9 liver homogenate contains per ml, 0.3 ml of the S-9 fraction, 8 mM MgCl2> 33 mM KC1, 5 mM glucose-6-P, 4 mM NADP, and 100 mM sodium phosphate (pH 7.4). The DNA concentration in all lysates were assayed by the method of Richards (20).
E. Treatment of DNA In vitro with Chemicals
A sample of B. subtilis transforming DNA (0.9 ml) in standard
saline citrate (sSc) (0.15 M NaCl-0.015 M trisodium citrate, pH 7.0) was
combined with 0.1 ml chloroacetaldehyde (1.0 M in DMS0) or 0.1 ml
CMA 003202
- ririr. '1.0 IS in T'.HO). The
was allowed zo reazt fcr I
hr l".d ccaasisr.il shading. Fcllovrir.g this trsatnsnt the treated DMA was
iialyrad at DC against three 5CC mi changes ox'' S3C for 24 hrs. In
alternate experiments the DNA-chemical mixtures were placed in a dialysis
bag and immersed in the S-9 liver homogenate mix. These samples were
dialyzed in SSC as above.
F. Competent Cultures for Transformation Assays
The procedures for the development of competence were similar to those described (23). B. subtills cells were grown in a modified Spizizen'3 minimnl medium (GLHJ (ft) for 90 min at 37C after cessation of logarithmic growth in a rotary incubator shaker. The cells were then diluted tenfold into CS.HI medium (29) and incubated for an additional 60 min at J7C in the shaker. At this time the culture has attained maximum competence.
G. Transformation Procedures
A sample (0.1 ml) of extracted, treated or untreated DNA was added to 0.3 ml of the competent cultures and incubated at 37C for 30 min in the shaker. The reaction was terminated by the addition of 0.1 ml of deoxyribonuclease (300 ug/ml, Worthington Biochem. Corp.) for 15 min at 37C. The cells were plated an appropriate selective minimal media and incubated at 37C for 48 hrs.
III. RESULTS
A summary of preliminary mutagenesis screening experiments with potential vinyl chloride monomer metabolites and related compounds is presented in Table II. It is evident that chlorooxirane and chloroacetaldehyde are the ultimate mutagens in this system. These results agree with the published data (3,16). Ta addition, this table describes the mutagenicity of the other chemical forms of chloroacetaldehyde, not ably a monomer hydrate, a dimer hydrate, and a trlmer. The hydrate and dimer hydrate forms have been shown to form an equilibrium mixture by the spontaneous rearrangement of chloroacetaldehyde under physiological conditions (Elmore, Wong, Laumbach, and Streips, submitted for publication),and these hydrate forms must be regarded as potential metabolites of consequence. Purified dimer hydrate and trlmer were synthesized under laboratory conditions. Neither acetaldehyde, chloroacetic acid, nor chloroethanol showed a significant level of mutagenicity in these assays. Other investigators have reported the mutagenicity of chloroethanol, however, either high concentrations or activation with microsomal enzymes was required for activity (3,16). Our results agree with those of McCann et al (16). These experiments suggest a molecular relationship involving the proximity of the chloride group to the aldehyde moiety for mutagenic activity. In this regard we are currently examining structurally analogous ketones, substituted with various halogens. Epichlorohydrin (l-chloro-2,3 epoxypropane) was also mutagenic in screens using the Salmonella tester strain TA100.
CMA 003203
Laumbach, A. D.,Lee, S., Wong, J., and Streips, U. N.
Further experiments examined the effect of proposed metabolites on several different DNA repair deficient strains of B. subtills. Chlorooxirane and the different forms of chloroacetaldehyde were all found to specifically inhibit the growth of strain MC-1, which lacks recombination repair (17) (Table III). Epichlorohydrin was capable of moderate reactivity only in the presence of the S-9 fraction.
Quantitative mutagenesis assays with Salmonella strain TA100, an indicator for base-pair substitution mutations, revealed that chloroacetaldehyde monomer had the highest mutagenic capacity of all the reactive metabolites (Table IV). The monomer-dimer hydrates, dimer hydrate, and trimer show progressively decreasing mutagenic efficiency as evidenced by the higher chemical concentration required for eliciting maximum reversion. All forms of chloroacetaldehyde were very toxic, thus the mutagenic response of each compound was limited to a narrow range of concentrations. However, epichlorohydrin, a weak mutagen by comparison, has a broad mutagenic spectrum and a corresponding low toxicity.
Since the mutagenic activity of the compounds constituted strong evidence that DNA was a primary target of attack, we examined the inter action of chloroacetaldehyde and epichlorohydrin with transforming DNA. It is known that the biological activity of transforming DNA can be altered by exposure to physical and chemical agents (8,22). Previous studies have shown that chloroacetaldehyde can bind to DNA in vitro (11). Accordingly, transforming DNA isolated from B. subtllis 168VT was treated with either chloroacetaldehyde or epichlor'ohydrin as described in Materials and Methods. The treated DNA was examined in transformation assays utilizing several different auxotrophic strains of B. subtills as the recipients. Data presented in Table V reveals that in-vitro treatment of DNA with either compound has little or no apparent effect on the biological activity of this DNA in transformation.
Since both chloroacetaldehyde and epichlorohydrin demonstrated mutagenic activity in the Salmonella TA100 strain, we examined the effect of these two compounds on B. subtilis DNA in vivo. Transforming DNA was isolated from B, subtilis following a 15 min exposure to the mutagenic chemicals. The DNA concentration was calculated from these samples, and levels equivalent to those used in the in vitro assays were added to competent cultures. The results of these transformation assays are shown in Table VT, Two major effects are evident with chloroacetaldehyde in vivo treated DNA. First, there was a major depression of the biological activity in the transforming DNA. Secondly, the depression showed genetic marker specificity. Moreover, the DNA segments containing genetic markers which have previously been shown to be associated to macromolecular structures such as the cell membrane (6,24,28) or the cell wall (Streips, Doyle, Sueoka, Brown, and Fan, submitted for publication) were selectively protected from attack by chloroacetaldehyde and epichlorohydrin. The activity of epichlorohydrin was less in these experiments, however, the patterns of specific marker inactivation are quite similar. The addition of the S-9 mix to the chemicals prior to addition to the cells, did not cause significant alteration in trans formation efficiency (results not shown). In some samples there was an effect on the transforming DNA by DMSO, therefore all transformation values were corrected to account for this parameter.
CMA 003204
The major findings reported in this manuscript can be summarized: 1) We have confirmed the mutagenicity of chloroacetaldehyde and chlorooxirane, and extended it to include the additional potential metabolites, chloroacetaldehyde monomer hydrate, dimer hydrate and trimer, as well as
have shown that recombination repair appears to be the mechanism for the correction of vinyl chloride metabolite elicited damage. 3) Chloro acetaldehyde causes a decrease in the biological activity of transforming DNA only if the cells are treated with the mutagen prior to the extraction of the DMA. In vitro studies shewed no effect. 4) Epichlorohydrin apparently differs markedly from the vinyl chloride metabolites in mutagenic activity.
To understand the mutagenic potential of an environmental carcinogen, such as vinyl chloride and related chemicals,it is necessary to determine both its metabolic fate and probable mechanism of action for alteration of cellular processes. This report, as well as others, (3,14,16) has identified the potential active metabolites in vinyl chloride monomer mediated carcinogenesis. Furthermore, on the basis of a series of studies in microbial systems, we can postulate probable mechanisms of action of the vinyl chloride monomer metabolites and related chemicals. Under standing of these mechanisms is necessary for the development of possible blocking agents to the carcinogenic activity.
Recombination repair appears to be induced to correct DMA lesions caused by vinyl chloride monomer metabolites and epichlorohydrin. Salmonella strain TA100 which lacks excision repair (uvr-), yet retains the capacity for recombination repair is capable of recovery and can express mutation following exposure. Furthermore, experiments with several repair-deficient B. subtills mutants demonstrate that only the recombination repair mutant is specifically sensitive to the active metabolites, whereas the excision repair mutants and the wild type strain are relatively unaffected. The nature of the lesions may specifically evoke the recombination repair mechanism (10), or, alternatively, the chemical reactivity of the metabolites may directly suppress other repair. It is known that recombination repair is inducible, while other types of repair are mostly constitutive (5). Since chloroacetaldehyde has been shown to specifically interact with proteins containing -SH groups (J. Hoffman, personal communication), it is possible that the chemical could inactivate the constitutive repair enzymes leaving the repair to an inducible system.
The requirement for recombination repair of damage induced by these chemicals suggests the potential route of mutagenesis in bacteria. Recombination repair has been shown to be error prone (16). In this sense it resembles postreplicatian repair in mammalian cells (13)* Thus, we can postulate that the analogous error prone repair pathway, post replication repair, may function in mammalian cells in response to vinyl chloride metabolite elicited damage. A relationship between post replication repair caused errors and somatic mutation and carcinogenesis has b en suggested in patients with the skin disease, xeroderma pig mentosum (13)*
CMA 003205
Laumbach, A. D., Lee, S., Wong, J., and Streips, U. N.
The increased inhibitory activity of the chloroacetaldehyde dimer and trimer forms for the other repair-deficient B_. subtilis strains (Table III) may have been nonspecific killing of""the cells, since all the strains other than MC-1 showed identical levels of inhibition. The necessity for metabolic activation of epichlorohydrin could reflect either a lack of permeability of the nonactivated compound or the requirement of a metabolite of this compound as the true mutagenic species.
Neither chloroacetaldehyde nor epichlorohydrin seemed to affect transforming DNA in vitro (Table V). Although several investigators have reported that CAA specifically modifies bases and causes mismatched base pairs (2,11), this reaction in vitro does not seem to affect the biological activity of the dHa. In"contrast, DNA which was isolated from cells treated with either chloroacetaldehyde or epichlorohydrin (in vivo, Table VI) was severely affected. The overall biological activity of tEe transforming DNA is depressed, and it appears that the regions of the genome which are not protected by either the cell membrane or cell wall are most susceptible to attack and inactivation. It has also been postulated both in Escherichia coli and B_. subtilis that the replication origin, terminus, and replication fork are all outer surface bound (18,24). Thus, these would be protected regions from chloroacetaldehyde attack and the nonreplicating DNA in the cytoplasm would be most susceptible. In this connection, recent experiments in our laboratory (Laumbach, Lee, Wong, and Streips, manuscript in preparation) have shown that chloroacetaldehyde causes enhanced mutation levels in cultures with nonreplicating genomes. This may imply that chloroacetaldehyde could be active in mammalian cells during growth stages where little DNA synthesis occurs.
The mode of action of epichlorohydrin, a known carcinogen (25), differs from that of the vinyl chloride monomer metabolites. Although epichlorohydrin causes similar base substitution mutations in Salmonella tester strain TA 100, it is a comparatively weaker alkylating agent based on quantitative assay. Epichlorohydrin also exhibits a lower toxicity level than vinyl chloride monomer metabolites, thus epichloro hydrin can demonstrate mutagenic activity through a wider range of concentrations. In addition, our laboratory has preliminary evidence that epichlorohydrin produces higher levels of mutation in Salmonella cultures which are actively replicating DNA than in cultures which have been arrested in DNA replication (Laumbach, Lee, Wong, and Streips, manuscript in preparation). The different activity spectra between chlorooxirane and its homolog epichlorohydrin points out the necessity for a multifaceted study of carcinogens.V.
V. SUMMARY
Our laboratories have utilized strains of B. subtilis and Salmonella typhimurium to investigate the mutagenicity of vinyl chloride : tabolites and related compounds. The major findings reported in this
mscript are: 1) Confirmation of mutagenicity of chloroacetaldehyde i chlorooxirane. 2) Description of mutagenicity of additional potential metabolites of vinyl chloride, chloroacetaldehyde monomer hydrate, dimer hydrate, and trimer, as well as the mutagenic
CMA 003206
STUD113 ON THE iIJTA'"-"-'IICI7Y CF VINYL CHLORIDE MZTASCLIT.o
q^
^
"a^ ^ fs a W1
^
qV
1 - ^ a^i n^1 C^*0
** t
*7 * "3 a ^ a a a 4 r* a * * ***
repair is postulated to be the .T.scr.sr.isr. for correcting vinyl chloride
metabolite elicited damage. 4) Chlaroacetaldehyde affects the transformation activity of DNA only if cells are treated with the mutagen prior to the extraction of the DNA. In vitro the chemical had no effect. 5) Epichlorohydrin differs from vinyl-chloride metabolites in mode of action.
VI. ACKNOWLEDGEMENTS
We wish to thank Mary A. Kinnaman for her extremely able technical assistance. We are grateful to Dr. Jerald Hoffman for making available preliminary results and to Dr. 3. N. Ames for providing the Salmonella taster strains. This v;orl v:as supported by a grant from the B. F. Goodrich Company to the Cancer Center at the University of Louisville, School of Medicine.
VII. LITERATURE CITED
1. Ames, B.N., Lee, F.D., and Durston, W.E. An Improved Bacterial Test System' For Detection And Classification Of Mutagens And Carcinogens. Proc. Nat. Acad. Sci. U.S.A., 70: 7S2-736, 1973.
2. Barrio, J.R., Secrist, J.A., and Leonard, N.J. Fluorescent Adenosine And Cytidine Derivatives. Biochem. Biophys. Res. Conan., 46: 597-604, 1972.
3. Bartsch, H., Malaveille, C., and Montesano, R.M. Human, Rat, And Mouse Liver-Mediated Mutagenicity Of Vinyl Chloride In S. fcypMwiiyjum Strains. Int. J. Cancer, 15: 429-437, 1975.
4. Creech, J.L., and Johnson, M.N. Angiosarcoma Of The Liver In The Manufacture Of Polyvinyl Chloride. J. Occup. Med., 16: 150-151, 1974.
5. Ganesan, A.K., and Smith, K.C. Recovery Of Recombination Deficient Mutants Of Escherichia coll K-12 From Ultraviolet Irradiation. Cold SpringHarbor Sy^>. Quant. Biol., 33,: 235-242, 1968.
6. Ganesan, A.T., and Lederberg, J. A Cell-Membrane Bound Fraction Of Bacterial DNA. Biochem. Biophys. Res. Comm., 18: 824-835, 1965.
7. Hefner, R.E., Watanabe, P.G., and Gehring, P.G. Preliminary Studies Of The Fate Of Inhaled Vinyl Chloride Monomer (VCM) In Rats. Ann. N. Y. Acad. Sci., 246: 135-148, 1975.
8. Jensen, R.A., and Haass, F.L. Analysis of Ultraviolet Light-Induced Mutagenesis By DNA Transformation In Bacillus subtilis. Proc. Nat. Acad. Sci. U.S.A., 50: 11C9-1116, 1963.
9. Kada, T., Tutikawa, K., and Sadaie, Y. In Vitro And Host-Mediated "Rec-Assay" Procedures For Screening Chemical Mutagens; And Phloxine, A Mutagenic Red Dye Detected. Mutation Res., 16^: 165-174, 1972.
CMA 003207
Laumbach, A. D., Lee, S., Wong, J., and Streips, U. N.
10. Laumbach, A. D., and Felkner, I. C. Formation Of A 4-Nitroquinoline-l-Oxide Complex With DNA In Normal And Repair-Deficient Strains Of Bacillus subtilis. Mutation Res., 15_: 233-245, 1972.
11. Lee, C. H., and Wetraur, J. G. Physical Studies Of Chloroacetaldehyde Labeled Fluorescent DNA. Biochem. Biophys. Res. Commun., 50: 879-885, 1973.
12. Lee, F. I., and Harry, D. S. Angiosarcoma Of The Liver In A Vinyl Chloride Worker. Lancet, 1: 1316-1318, 1974.
13. Lehmann, A. R. Postreplicatian Repair Of DNA In Mammalian Cells. Life Sci., 15: 2005-2016, 1974.
14. Malaveille, C. H., Bartsch, H., Montesano, R., Barbin, A., Camus, A. M., Croizy, A., and Jacquignon, P. Mutagenicity Of Vinyl Chloride, Chloroethylene Oxide, Chloroacetaldehyde And Chloroethanol. Biochem. Biophys. Res. Commun., 63: 363-370, 1975.
15. Maltoni, C., and Lefemine, G. Carcinogenicity Bioassays Of Vinyl Chloride. Environm. Res., 7: 387-405, 1974.
16. McCann, J., Simmon, V., Streitwieser, D., and Ames, B. N. Mutagenicity Of Chloroacetaldehyde, A Possible Metabolic Product Of 1,2-Dichloroethane (Ethylene Dichloride), Chloroethanol (Ethylene Chlorohydrin), Vinyl Chloride, And Cyclophosphamide. Proc. Nat. Acad. Sci., U.S.A., 72: 3190-3193, 1975.
17. Okubo, S., and Romig, W. R. Impaired Transformability Of Bacillus subtilis Mutant Sensitive To Mitomycin C And Ultraviolet Radiation. J." Uol. 'Biol., 15: 440-454, 1966.
18. Olsen, W. L., Heidrich, H. G., Hannig, K., and Hofshneider, P. H. Deoxyribonucleic Acid-Envelope Complexes Isolated From Escherichia coli By Free-Flow Electrophoresis: Biochemical And Electron Microscope Characterization. J. Bacteriol., 118: 646-653, 1974.
19. Rannug, U., Johansson, A., Ramel, C., and Wachtmeister, C. A. The Mutagenicity Of Vinyl Chloride After Metabolic Activation. '*8310, 3: 194-197, 1974.
20. Richards, G. Modifications Of The Diphenylamine Reaction Giving Increased Sensitivity And Simplicity In The Estimation Of DNA. Anal. Biochem., 57: 369-376, 1974.
21. Strauss, B., and Okubo, S. Protein Synthesis And'The Induction Of Mutations In Escherichia coli By Alkylating Agents. J. Bacteriol., 79: 464-473,
22. Strauss, B., Reiter, H., and Searashi, T. Recovery From Ultra violet And Alkylating Agent-Induced Damage In Bacillus subtilis. Rad. Res. Supp., 6_: 201-211, 1966,
23. Streips, U. N., and Young, F. E. Transformation In Bacillus subtilis Using Excreted DNA. Molec. Gen. Genetics, 133: 47~55, 1974.
CMA 003208
* U'--.<*L-**w*i *-l ***y a
'* .**--.--------------- ------------ -
---w
.ca.ti.cn Origin In A,. ,. Bid., 33*. 695
--* a-*-* --
c ,*
25. Van Duuren, B. L. On The Passible Mechanism Of Carcinogenic Action Of Vinyl Chloride. Aim. N. Y. Acad. Sci., 246: 253-267, 1975.
26. Viola, P. L., Bigotti, A., and Caputo, A. Oncogenic P.sspi Rat Shin, Lungs And Bones To Vinyl Chloride. Cancer Res. 31: 516-
522, 1971.
27. Vogel, H. J., and Bonner, D. M. Acetyloroithinase Of Escherichia eoli: Partial Purification And Some Properties. J. Biol. Chen.,
OTT 97-106, 1956.
23. Yamagudin, K., and Yoshikawa, H. Association Of The Replication Terminus Of The Bacillus subtills Chrcsoscne To The Cell
Membrane. J. BacterlolT, 3.24: 1030-1033, 1975-.
29. Young, F. E Of Genetics 114, 1974.
and Wilson, G. A. Bacillus subtilis. In: Handbook Ed.; Robert C. King, Plenum Press, New York, 1: 69-
003209
Laumbach, A. D., Lee, S., Wong, J., and Streips, U. N. Table I
Bacterial Strains
Bacillus subtilis
Genotype
Origin and Comments
RUB 783 BR 151 BUL 709 BUL 714 Hcr-9 (JB01-200) MO-1
FB-13 168WT
purB6, leu-8, hisAl, metBlQ trpC2, lys-3 metBlO ura-1, hisAl, leu-3, metBlO cysA, hisAl, leu-3, metBlO trpC2
trpC2, recB2 trpC2 prototroph
U, Streips B. Reilly This laboratory This laboratory S. Okubo and W. Romig, her-
S. Okubo and W. Romig, rec" C. Hadden, uvr" A. Laumbach and I. Felkner
Salmonella typhimurium
Mutations in Strains His" LPS DNA Repair ]3 Factor
Mutation Detected
TA1535 TA100 TA1537 TA1538 TA98
hisB46 rfa hisB46 rfa hisC3076 rfa hisD3052 rfa hisD3052 rfa
uvrB uvrB uvrB uvrB uvrB
base-pair substitution pKMIOl base-pair substitution
frameshift frameshift pKMIOl frameshift
CMA 003210
STUDIES ON THE MUTAGENICITY OF VINYL CHLORIDE METABOLITES"Tails II
llutagenic Activity Assayed by 3acxerial Test Systems
Compounds
Indirect Screen B. subtilis
"Repair-Assay"
Direct Test3, S. typhimurium
Strain IA1QQ
Acetaldehyde
Chloroacetia .Acid
Chloroethanol
Vinylidene Chloride
Vinyl Chloride
Chlorooxirane
Chloroacetaldehyde (monomer)
Chloroacetaldehyde (monomer-dimer hydrates)
Chloroacetaldehyde (dimer hydrate)
Chloroacetaldehyde (trlmer)
Eplchlorohydrln
NRb NR MR NR NR
+C
+*+s
++
4*
+
NR
NR .NR NR NR
++
aEiperlmenta performed in absence of liver homogenatemediated activation. *NR no reaction detected
c + Reactive <!*.- Moderately reactive
>++ Very reactive
Cflia 32ll
Table III "Repair-Assay" with Bacillus subtllis Strains
Molar
Growth Inhibition in Millimeters6
Compounds
Concentration
168WT
MC-1
Hcr-9
FB-13
(hcr+, rec+) (hcr+, rec-) (her-, rec+) (uvr+, rec+)
2!
t> Chloroacetaldehyde
0.10
2.0 28.0 4.0 3.0
(monomer)
Pi
*rt
Chloroacetaldehyde
0.115
NIb 23.0
NI
NI
CO (monomer-dimer hydrate)
.1 Chloroacetaldehyde 0.097 2.0 10.0 2.0 2.0
(dimer hydrate)
"3
130 B
Chloroacetaldehyde (trimer)
0.096
7.0 15.0
6.0
7.0
Chlorooxirane
0.26
HI 10.0 NI
to
V Epichlorohydrin 1f-t1) Epichlorohydrin
0.997
NI
NI
NI
o
(plus liver homogenate)0
0.997
NI
3.0 NI
NI NI
NI
-4 aAverage inhibition calculated from multiple experiments.
Xt
8
^No inhibition detected.
c9,000 x g supernatant (S-9) + NADPH generating system.
ia-)l
Table IV Quantitative Mutagenicity Asaay by Salmonella TA100 Reversion
Compound
Concentration in Soft Agar Layer irM/Platea
Chloroacetaldehyde (monomer)
Chloroac e taldehyde (monomer-dimer hydrate)
Chloroacetaldehyde (dimer hydrate)
Chloroacetaldehyde (trimer)
Epichlorohydrin
0.0004 0.054 0.490 0.240 4.746
"Highest effective non-toxic concentration for reversion. ^Spontaneous background revertante subtracted.
Average Humber Revertants/Plate^
265 977
311 159 2856
Table V Effect of Chloroacetaldehyde and Epichlorohydrin of Trans foralng DNA In vitro
Recipient Strains c
Relative Transformation Efficiency metBlO leu-8 cysA hlsAl ura-1 trpC2 lys-8 purB6
t(moHN o U
z Epichlorohydrin treated DNA
mp. BUL 714
H
4)
+CO>
RUB 783
.92 .97 .97 1.16
.91 .60
.98
.77
BUL 709
1
.99 .95
1.02
.85
BR 151
1.48
1.07
.62
Chloroacetaldehyde treated DNA
BUL 714
1.43 .92 .55 .91
10
RUB 783
.93 1.45
.75
.89
BUL 709
.86 1.33
.90 .75
Q BR 151 <t*!
NDb .77
jocdd
Relative transformation efficiency calculated: number of transformants with treated DMA
^Not determined
number of transformants with untreated DNA
i-al) Conditions for competence and transformation as described in Materials and Methods.
Table VI EFFECT OF CHLOROACETALDEHYDE AND EPICHLOROHYDRIN ON TRANSFORMING DNA IN VIVO
STUDIES ON THE MUTAGENICITY OF VINYL CHICHIDE METABOLITES
CMA 0 0 3 2 1 5
Recipient Strains^
Relative Transformation Efficiency metBlO leu-8 cysA hisAl ura-1 trpC2 lye-3 purBl6
Chloroacetaldehyde in vivo treated DNA
BUL 714 RUB 783 BUL 709 BR 151
.54 .09 .08 .36
.33 .10
.35
.53 .07
.32 .34
.37 .13 .11
.10
Eplchlorohydrin in vivo treated DNA
BUL 714 RUB 783 BUL 709 BR 151
.55 .17 .25 .46
.52 .15
.38
.59 .15
.50 .36
.37 .11 .19
NDC
Relative transformation efficiency calculated: number transformants with treated DNA number transformants with untreated
^Conditions for competence and transformation as described in Materials and Methods.
cNot determined.
VINYL CHLORIDE MUTAGENICITY AND CARCINOGENICITY VIA THE METABOLITES
CHLQROOXIRANE AND CHLOROACETALDEHYDE MONOMER HYDRATE.
Jim D. Elmore and John L. Wong* Department of Chemistry, University of Louisville Andrew D. Laumbach and Uldis N. Streips* Department of Microbiology, University of Louisville Louisville, Kentucty, USA 40208
11
'. SUMMARY Mutagenicity tester strains of Bacillus and Salmonella were used to
assay vinyl chloride in nutrient broth at a practical concentration level. Also screened without exogenous activation were seven potential metabolites of vinyl chloride in their pure forms as well as the related epichlorohydrin. Chlorooxirane, chloroacetaldehyde, chloroacetaldehyde monomer hydrate, chloro acetaldehyde dimer hydrate, chloroacetaldehyde trimer, and epichlorohydrin produced significant mutagenic activity in Salmonella typhimurium strains sensitive to base-pair mutation. A recombination repair deficient strain of Bacillus subtil is was inhibited in growth by these compounds, whereas excision repair deficient and wild type strains of Bacillus subtil is v/ere relatively unaffected. On the basis of these assays a working hypothesis for the vinyl chloride carcinogenesis mechanism is proposed which involves chlorooxirane and chloroacetaldehyde monomer hydrate as the ultimate carcino genic metabolites of vinyl chloride.
CMA 003216
c
INTRODUCTION
The carcinogenic potential of vinyl chloride monomer 1 was initially
"V
established by Viola et al_. [1] and Mai torn' et al. [2] with inhalation experiments using laboratory animals. Detection of angiosarcoma in polyvinyl chloride workers suggested a causal relationship between industrial exposure to vinyl chloride and the development of pathological conditions in humans. This contention was supported by epidemiological data which revealed an association between exposure to 1 and the onset of hepatic abnormalities including angiosarcoma [3,4], A report by Hefner et al. [ 5] on the metabolic fate of 1 in rats indicated that 67% of the vinyl chloride Inhaled by the rats was metabolized and excreted in the urine. The metabolic products identified were N-acetyl-S(2-hydroxyethyl)cysteine and thiodiglycolic acid 5,6] which are sulfhydryl conjugates of chloroethanol 2 and chloroacetic acid 3 respectively. Chlorooxirane 4 and chloroacetaldehyde 5 were speculated to be the carcinogenic . forms. We report herein the mutagenicity and carcinogenic potential of these compounds in their pure forms.
Several reports [7,8,9] have appeared recently using the Salmonella tester strains to test vinyl chloride and several of its supposed metabolic derivatives. Vinyl chloride and chloroethanol were found to be mutagenic after activation by liver homogenates [9]. Direct mutagenicity of vinyl chloride was also reported by McCann e al_. [7] and Bartsch et_al_. [10]at 20% v/v in air (200,000 ppm). Since the solubility of vinyl chloride in water at 25C and 1 atm has been determined to be 7.79 x 10"^ mole fraction [11] or 2,900 ppm, we have conducted further testing at this concentration level to secure a practical
CMA 003217
jCai-< 2$penje ce.Tiper'isen *<n - -s proximate ~c: a jg : i g w s. P^coro ~tr,^ z~
lattar, tr.3 exact cha~ica'. forms of the orexinate neoaoolices crev'OMs; y tasted ara oftsn cuast-iar.ab! e. Chloroacebaidehyde, like fcmaldehyce ["*2;, dichloroacetaldahyde [13], and chloral [14], can exist in combinations of four forms depending on the history of sample preparations: the monomer 5, the
v monomer hydrate 6, the dimer hydrate 7, and the trimer 8. McCann et al. [7] used vacuum distilled chloroacetaldehyde without a follow-up analysis of its content. This distillate may have consisted of chloroacetaldehyde monomer A5. and its cyclic trimer 3*\i if water was tGtally absent, or it may have bean a mixture of chloroacetaldehyde hydrates 6 and 7 in an aqueous medium, Bartscn et al_. [IQ] tested a conmercial aqueous chloroacetaldehyde solution which, according to our analysis reported herein, had an acidic pH and approximately equal concentrations of the two hydrates 6 and 7. This solution was also contaminated by ethanol to the extent of 10%. We have therefore conducted individual assays of pure compounds, or assays of a known mixture of the specific forms of chloroacetaldehyde. Furthermore, the mutagenicity observed for chlorooxirane 4 [9] may be attributed to a chloroacetaldehyde hydrate rather than the chlorooxirane integrity. Under the 37*C aqueous testing conditions reported, chlorooxirane decomposed with a half life of 1.6 min [10] to chloroacetaldehyde. For this reason we have also screened epichlorohydrin 9 which is a stable chloro-epoxide homolog of 4 as a comparative assay to interpret the observations of the activity of chlorooxirane.
This investigation used the above-mentioned compounds 1^ - 9 in mutagen assays without exogenous enzyme activation. A preliminary screen was performed using DNA repair-deficient mutants of Bacillus subtil is. This was followed by quantitative testing of the compounds for mutagenicity
003218
4
with Salmonella typhimurium LT-2 strains [15]. Thus, a combination of these two screening procedures have led to information on the mutagenicity and carcinogenic potential of these compounds as well as their chemical mode of action.
MATERIALS AND METHODS The bacterial strains used in the bioassays are shown in Table I. The
Salmonella tester strains were designed to detect chemical carcinogens as mutagens [15]. The recombination and DNA repair-deficient Bacillus subtil is strains were used in the repair assays as an indirect test for mutagenicity [16,17]. Nutrient broth (Difco) and nutrient broth plus 0.5% NaCl was used for growth of stock cultures of Bacillus and Salmonella strains respectively. Nutrient agar (Difco) served as a solid medium for the growth of Bacillus strains in "repair-assays". The pour plates used with Salmonella strains consisted of molten (45C) soft agar which contained 0.6S agar, 0.6% NaCl, 0.5mM biotin, and 0.5 mM histidine. The minimal agar plate was composed of Vogel-Bonner E medium [18], 1.5% agar, and 2% glucose.
Vinyl chloride gas was obtained from Matheson Scientific; aqueous chloroacetaldehyde (45% by wt.) from ICN Pharmaceuticals; epichlorohydrin from Matheson Coleman and Bell; and other chemicals from Aldrich Chemical Co.
Mutagenicity Assays Salmonella - Vinyl chloride 1 was tested by the method of Ames [7], A mixture 'V
of 0.1 ml of 1 in broth and 2 ml of top agar was added to 0.1 ml of cell culture. The solutions were then mixed and poured immediately onto the surface of a minimal medium plate. After incubation for 48 hrs at 25*0, colonies were counted and recorded. For compounds 2 - 9,sample solutions of known concentrations
CMA 003219
J
wera prspsrsd in diTatiiyl sulfcxids (2.'*0). A 0.1 ml aliqust of tha sample
solution was admixed with 0.9 ml of the tester strain culture. Then, a
'`J'-*1
^ '".l Cf
^ay*:y* * -- .J
applied to tha surface of a minimal agar plata. Control plates for detection of the spontaneous reversion rates were prepared for each tester strain by omitting only the compounds tested. Pour plates were incubated for 48 hr at 37*C before revertant colonies to prototrophy were counted. For positive mutagenesis control, plates containing the mutagen 4-nitroqulno!ine-N-oxide ./.->re used.
Bacillus - The "repair-assay" procedure was a modification of the "recassay" procedure of Kada et al_. [19]* They were grown overnight in nutrient broth then diluted 10 fold in phosphate buffer (pH 7.0). Strains were streaked with pipettes onto nutrient agar plates. Filter paper discs (6 mm) saturated with test solution were placed upon the bacteria streaks. Following incubation for 24 hr at 37*C, growing bacteria were visible except in the inhibition zone. The lethality and mutagenic potential of compounds were assessed by comparison of inhibition zones between the 168 wild type strain and the DNA repair-deficient strain and the DNA repair-deficient strains. The control used was 4-nltroquinoline N-oxide. Survival assays for 6 and 7 (cf.. Fig. 3.) were made in MY-1 broth [17) solutions. Cultures were grown in tryptose blood agar base for 16 hrs, inoculated into MY-1 broth, and viable cell counts were done on TBAB agar plates.
Compound Synthesis and Purification Chlorooxirane 4 prepared by the method of Walling and Frederick [20] was in
higher purity (951 pure) than that by molecular chlorination [21] (50% pure).
Thus, t-butyl hypochlorite and ethylene oxide at -10*C with 200 watt tungsten
lamp irradiation yielded chlorooxirane 4; glpc (gas liquid phase chromatography)
*
003220
u
tR B 1.2 min at 5Q*C, infrared absorption ( vcm-^) 900, 1250, 1320, and
1710 as described previously [211, and PMR as shown in Table II. Derivatization of 4 with an excess of acidic 2,4-dinitrophenylhydrazine solution gave glyoxal-bis-dinitrophenylhydrazone, mp 317-318"C (317X reported[21 ]).
Chloroacetaldehyde monomer 5 was obtained in the purest form by cracking the chloroactaldehyde trimer 8 at 95C and distilling it into dry DMS0; glpc t^ 2.25 min at 100 WC and PMR as shown in Table II.
Chloroacetaldehyde dimer hydrate 7 - A solution containing 49.5 ml of 38% hydrochloric acid, 30 ml of the 45% aqueous chloroacetaldehyde solution, and 55.5 ml of water was distilled over a 9 inch Vigreaux fractionating column. The fraction (1/5 of the initial volume) collected from 87-100*C was redistilled. This second distillate at 83-92*0 crystallized after 3 days, at -15C. Upon sublimation of 60*0 and 1 atm, white crystals of 7 were obtained; mp 55C and PMR as shown in Table II.
Chloroacetaldehyde trimer 8 - Concentrated sulphuric acid (7.5 ml) was added to the 45% aqueous chloroacetaldehyde solution (5 ml) with vigorous stirring and external cooling (-5C). The crystalline precipitate was filtered after standing overnight at -15C, washed with 5 ml of cold 20% aqueous methanol, and recrystallized 5 times from cold methanol; mp 87-88*0, corresponding to that reported by Natterer [13], and pMR as shown in Table II.
Quantitation of vinyl chloride in nutrient broth - The concentration
of vinvyl
chloride 1 a..
in
the
broth
solution was
determined
by an
extraction
method in conjunction with glpc. This method involved (1) establishing the
003223. CMA
7
linearity of the response of 1 on glpc, (2) constructing a standard curve of vinyl chloride weight vs.. peak area, and (3) extracting the broth witn methylene chloride followed by glpc determination. (1) Linearity of response - A standard solution of 1 was prepared by condensing it (bp -13.4"C) at -78*C onto a known weight of methylene chloride in a 1 ml volumetric flask fitted with a serum cap. The condensed vinyl chloride was determined by weighing. A typical solution thus prepared was 0.2377 M and was subjected to glpc analysis by varying injection sizes from 1-9 ul. The correlation of vinyl chloride weight and peak area was made by a least square computer routine: slope * 0.877, with an index of correlation of 0.972 (ideal 1.00) up to 6 U1 (0.1078 mg) of injection. (2) A standard linear curve using the above technique was established for 0.01-0.10 mg of vinyl chloride. (3) Extraction of broth Vinyl chloride was allowed to bubble through the nutrient broth for 30 min at 25*C. A 1.0 ml broth sample was then extracted with 4 x 2 ml of methylene chloride, the extracts were combined and then made up to 10 ml in a volumetric flask with methylene chloride. Glpc analysis of this solution and application of the standard curve showed that there was 7.0 mg of 1 in the 10 ml solution, or the concentration of 1V in the broth was 0.0107 M. Repeated determination showed it to be 0.0105 M.
High Pressure Liquid Chromatographic (HPLC) Analysis of the Commercial 45% Aqueous Chloroacetaldehyde - Reverse phase HPLC on the commercial 45% chloroacetaldehyde solution (7 M, pH 2.6) resolved it into two components: tRl - 6.3 min and tR2 8.8 min in a ratio of 40:60. The ratios of the two peaks on the chromatogram changed as the solution pH was varied by addition of 1 N NaOH at room temperature: 43:57 (pH 3.7), 44:56 (pH 5,0), 48:53 (pH 7.6),
003222
and 56:44 (pH 8,2). The first eluted component at t^l = 6.3 min increased while the second at t^2 8.8 min decreased at raised pH's. This indicated a retrograde aldol condensation type hydrolysis. The first peak was assigned to the monomer hydrate 6 and the second to the dimer hydrate 7. When the 45% solution was diluted to 0.44 M at pH 3.6, refluxed for 1 hr, cooled, and chromatographed, the ratio of t^l:t^2 became 33:67. This suggests an acidcatalyzed condensation of 6 to form the dimer hydrate 7. When these two components were analyzed by glpc, both emerged at the same retention time (t-ft * 2.8 min at 60C) as that of the monomer %5. Dehydration of 6** and 7* must have occurred under the glpc conditions thereby reverting them to the monomer form. As shown in Table II, the PMR spectra of 6 and 7 are resolved from one another. Thus, the PMR spectrum of the 45% commercial solution also revealed the presence of both hydrates 6 and 7 with approximately the same integrals.
Instrumentation
t
High Pressure Liquid Chromatography (HPLC) - A Waters Associates model
600 pump combination (dual) with a model 440 differential 254 nm ultraviolet
detector were used for the analysis of aqueous chloroacetaldehyde solutions.
A Porasil Bondapak ^C^g 4 mm x 30 cm column was used with a 80:20 v/v 0.1
N NH^HgPO^-MeOH isocratic eluant (pH 4.9) at 1 ml/min. These two components
were also resolved on a Reeve Angel Partisil 10 0DS 4.6 mm x 25 cm column using
the same eluant.
CMA 003223
u
Gas Licuid Phase Chromatography <21?
Analysis of vinyl chloride
1, chlorooxirane 4, and cnloroacetalrienyde 5 ..are performed on a Carlo
model 9500 flame ionization gas chromatograph. A 1C.11 SE-30 on Anakrcn 60/70
packed column was used at 30*C for vinyl chloride determination. A 20%
Carbowax on chromosorb W column at 50"C and 4Q ml/min of Helium was used
for analysis of 4 and 5 unless specified otherwise. Both were 0,125 inch
x 5 feet stainless steel columns.
Protcr. Magnetic Resonance (PMR) - Spectra were obtained using a Varian A-60 A and a Perkin Elmar R-12 spectrometer. Solutions of D20 and DM$0-dg were used with 3-(trimethylsilyl)propanesulfonic acid sodium salt as internal reference. Tetramethylsilane was used as a reference in CDClj and CCl^. Probe temperature was 38 X.
RESULTS AND DISCUSSION
Mutagenicity assays with Bacillus and Salmonella for compounds 1-9 are summarized in Table III. They are grouped into three categories in subsequent discussion. Further testing data are included in Tables IV-VI and Figures 2-4.
Nonmutaqenicity of vinyl chloride, chloroethanol, and chloroacetic acid Only high concentrations of vinyl chloride (20% v/v in air) have produced mutagenic action in previous assays with the Salmonella tester strains 19,10]. We have found that tests with both the Salmonella and the 8acillus cultures were negative within the practical solubility range of vinyl chloride in the nutrient broth under ambient conditions. Figure i shows the stability of a
CMA 003224
presaturated vinyl chloride broth solution at 25*C and 1 atm. The initial concentration of 0.022 M of vinyl chloride 1 rapidly decayed by 50% in 15 hr. Thereafter the escape of ^ from the broth slowed considerably. In the next 45 hr there was a further decline of only 18%. Thus the bacteria strains (B_. subtil is MC-1 and Salmonella -TA 100) were exposed to the stabilized solution of 0.0106 M (723 ppm) of vinyl chloride in the nutrient broth. The negative activity observed was not unexpected since vinyl chloride lacks the electrophilic character common to many mutagens [23]. Although the direct mutagenicity of vinyl chloride at 200,000 ppm (20% v/v in air) observed previously [10] may be real, the chronic human exposure problem most likely requires metabolic activation of vinyl chloride to an electrophilic reactive form [8]. Also tested were chloroethanol '2v. and chloroacetic acid 3 which probably are metabolic intermediates as shown in Scheme I. Both S-(2-hydroxyethyl)cysteine and
SCHEME I: Vinyl Chloride Metabolites
CH,, CHC1 1
C1CH--CH-0H 2 --- ------- 2 2 ^ SH
-02C-CH(NH3+)-CH2 I
ho-ch2-ch2-s
cellular
C1-CH2-C02H 3
------- * S(CH2-C02H)2
thiodiglycolic acid in Scheme I have been identified [6] as the urinary metabolites of vinyl chloride. Neither chloroethanol 2 nor chloroacetic acid 3 exhibited any mutagenic effects at 1 mM concentration in our mutagenicity assays (cf. Fig. 2 ). Although Bartsch et al^DO] found-considerable mutagenic
CMA 003225
activity with chloroethanol 2 for TA 1530 strain in the absence of microsomal A.
activation, cur observations csrrccorate wi :;h those of "cCar.n r- al_. [7] . showed that %2 was weakly mutagenic directly even at high concentrations r'or the sensitive TA ICO and that it showed only trace activity for TA 1535. The enhanced activity of 2 after microsomal activation observed by these groups suggests that chloroacetaldehyde derivatives were being formed from chloroethanol. We have found potent mutagenicity and lethality with the various forms of chloroacetaldehyde as shown in Figures 2-4 and Tables IV-V.
Mutaqenasis of chloroacetaldehyde, the monomer hydrate, dimer hydrate, and the trimer - When chloroacetaldehyde 5 was distilled into distilled water, a mixture of the monomer hydrate 6 and the dimer hydrate 7 was formed instantly as determined by HPLC and PMR spectroscopy. Analysis of the commercial 452 aqueous chloroacetaldehyde solution with the same techniques showed a 50:50 mixture of the two hydrates. Upon standing under dry conditions, the monomer 5 cyclized to form trimer 8, The trimer was sparingly soluble in water, but \ 'V was disproportionated upon heating in water to form the hydrates 6 and 7.
Purified samples of chloroacetaldehyde \5, the commercial 452 chloroacetaldehyde solution containing a 50:50 mixture of the hydrates 6 and 7, the dimer hydrate 7, and the trimer 8, in DMS0 solutions were tested for mutagenic potential. The data in Table IV summarizes the results of the repair assays with B. subtilis. Chloroacetaldehyde 5 and the monomer hydrate 6 specifically inhibited the growth of B. subtilis MC-1, a mutant lacking recombination repair of DNA. These unrepaired DNA lesions then led to cell death. However, compounds 5 and 6 did not inhibit the wild type B^. subtilis or those mutant
CMA 003226
strains (Hcr-9, FB-13) having the capacity for recombination repair. In contrast, purified samples of the dimer hydrate 7 and trimer 8 inhibited all of the mutants as well as the wild type, although MC-1 again demonstrated the most sensitivity. It is unlikely that 7 and 8 caused DNA lesions that
'X. \ are different from those by 5 and 6 because the excision repair mutants and
*\# 'V the wild type were inhibited to an equivalent extent. Inhibition of these strains by 7 and 8 may result from a metabolic poisoning or cellular damage similar to that observed in Escherichia coli after exposure to vinyl chloride waste [24 ].
Viability assays on B. subtil is strains during short term exposure to the chloroacetaldehyde 5 revealed that recombination repair was essential for
X. recovery (Figure 2). The B. subtil is strains with recombination repair cap abilities displayed repair kinetics as evidenced by the shoulders in curves in Figure 3. The sensitive MC-1 strain lacking recombination repair yet having excision repair was rapidly killed following the exposure. We surmise that these DNA lesions caused by the chloroacetaldehydes were repaired solely by the recombination repair mechanism.
The direct mutagenic potential of the samples 4-9 was determined by the 'V A*
mutations expressed in Salmonella strain TA 100. The dose response relation ships of these compounds (cf. Table V), and the dose-response curves (cf. Figure 4 ) were determined v/ith strain TA 100. At high concentrations the dose response curves for all compounds became nonlinear because the toxicity of the chemicals reduced the number of potential revertants on the plates. The reduction of the cell population by high concentrations was confirmed by viable counts and observations of decreased background lawn on the test plates.
CMA 003227
Oita from the dose resoo-.se curves (Figure 4) showed that chloroacataldehyda 5 and the rrorc-er hydrate 6 ware more active than 7 and 8,
^ ^ \\ The monomer 5 was the most mutagenic as predicted because its electrophilic
'V
carbonyl group remains intact. The restoration of the carbonyl character to the monomer hydrate 5 can be projected in hydrophobic environment of the cell membrane by loss of water, hence its mutagenicity is also explicable. The substantial activity of the dimer hydrate 7 can be attributed to its ready equilibrium with the monomer hydrate 6 in aqueous medium. The relation
al ship of the activity of the cyclic trimer 8 to the chloroacetaldehyde action cannot be deduced on the basis of the curves in Figure 4. Nevertheless, these mutations were the base-substitution type and were expressed in Salmonella strains TA 100 and TA 1535, The mutagenic response in TA 1535 was very weak as compared to TA 100. It should be noted that the latter contains an "R" factor that enhances mutation by an error-prone recombination repair mechanism following DNA damage [7],
Comparison of mutagenic response of chlorooxirane with its methylene homoloq epichlorohydrin - The prevailing opinion [SI is that chlorooxirane %4 is the primary metabolite of vinyl chloride and is derived from the action of the microsomal mixed function oxidase. This compound, prepared independently from chlorination of ethylene oxide, was found to rearrange readily to chloroacetaldehyde in aqueous or 0MS0 solution at,, ambient temperatures. A kinetic
study of a 0.15 M solution of 4 in a D20-DMS0-d- (80:20) mixture at pO 7.1 and 4*C by PMR technique showed that the rearrangement followed first order kinetics, k (sec"1) - 2.5 x 10-4. This translatesto a half life of 46.2 min
003228
k' at 4*C as compared to 1.6 min at 37Ct9l. Such instability allows only limited
testing in the cold as well as interpretation of the results. On the other
hand, epichlorohydrin 'X9# , which can be considered the epoxidation metabolite of ally! chloride, is a methylene homolog of 4. Both 4 and 9 are structurally
bis-alkylating agents, hence comparing their mutagenic activities will lend
insight into the mode of action of chlorooxirane 25,26]. Table IV tabulates
the mutagenic response of these two compounds in the Bacillus repair assay
and Table VI the Salmonella TA 100 reversion. Due to the instability of
chlorooxirane at 37C, the assays shown in Table VI were preincubated at 3*C
in solution with the Salmonella TA 100 strain before plating to insure that
chlorooxirane could reach the cells intact. Mutant strains of B. subtil is
were not inhibited when exDOsed to high concentrations of epichlorohydrin 9.
In contrast, chlorooxirane 4 selectively inhibited the rec" strain MC-1 in
a manner similar to chloroacetaldehyde hydrate %6. Tests with Salmon' ella showed that strain TA 100 was very susceptible to the mutagenic action of both
epoxides 4 and 9. However 9 was less toxic to the tester strains than 4. The
% <\i
'V
low toxic effects of 9 indicate a different type of DNA lesion compared to that
caused by chlorooxirane 4. It is possible that 9 may react with DNA by a
mechanism which does not cause potential lethal strand-scissions. On the
other hand, chlorooxirane 4 may act on the bacteria via a NIH shift27,28] to A/
form chloroacetaldehyde 5 or 6. Conceivably, chlorooxirane can also behave
as a diradical intermediate rather than a conventional S^l or S^2 type alkyl
ating agent in its reaction with DNA.
Vinyl chloride carcinogenesis mechanism hypothesis - Among the comoounds tested in the metabolic Scheme II. chloroacetaldehyde 5 and chlorooxirane 4
CMA 003229
in
SCHEME II: The metabolic pathways of vinyl chloride [5],
I. CI-CH=CH- 1
Cl -C;-!2-CH2-CH 2-
SCHEME I
r-. r.e
Ro1 >Cl-CH2-CHO 5
dehydrogenase
^
ci-ch2-cho 5-
C1-CH2-C02H 3
SCHEME I
urine
II. C1-CH2-CH2-0H l
h2 catalase
C1-CH2-CH2-CCH
C1-CH--CK0 5 A.
III. Cl-CH-CHc* ^1
oxidase
Cl-CH-CH-0 4 I____ ] *
ci-ch2-cho
were the most mutagenic with the lowest toxic side effects. Hence, they may qualify to be the active carcinogenic derivatives of vinyl chloride. Consider ing the aqueous milieu of the metabolic environment, however, the chloroacetaldehyde monomer hydrate 6 is a more realistic choice as an ultimate carcinogen than the monomer 5 which reacts immediately with water. Viability assays
% followina exoosure of the B. subtil is mutants to 6 indicated that the compound induced recombination repair. The strain with the rec* phenotype (MC-1) was immediately inactivated. All the rec+ strains showed survival ability
and repair kinetics of similar nature. It has been shown [27] that mammalian cells have postreplication repair of DNA which has many similar features to the recombination repair in bacteria. In addition, a relationship between this mammalian postreplication repair process and mutation as well as carcinogenesis
CMa 323o
has been suggested 1241. Cells from patients with the skin disease xeroderma pigmentosum lack the ability to excise pyrimidine dimers and must rely on postreplication repair to remove these lesions[24]. It is believed that this error prone process of postreplication repair is responsible for the production of somatic mutations and cancer in patients with this disease. Since chloro-
*
acetaldehyde monomer hydrate 6 induces recombination repair in bacteria responding to lesions, it may also be capable of activating the error prone postreplication repair in exposed mammalian cells. At the molecular level, chloroacetaldehyde is known to react with N and N nitrogens of adenosine and N3 and N4 nitrogensof cytidine in single-stranded DNA [28,29]. It therefore appears that chloroacetaldehyde monomer hydrate 6 should merit our consideration as an ultimate carcinogenic metabolite of vinyl chloride.
The lower mutagenic activity of chloroxirane 4 compared to 6 may reflect the unstable nature of chlorooxirane as an a-chloroether. While the carcino genic chloromethyl methyl ether is a bifunctional alkylating agent [3C8, the mutagenic activity of chlorooxirane cannot be so categorized, especially when it is compared with epichlorohydrin 9. One mode of action of chlorooxirane is a rearrangement to chloroacetaldehyde via the NIH shift [27,28]. Another is a homolytic ring cleavage to yield a stabilized diradical inter mediate CICH-CI^O. Both are capable of reacting with DNA, thereby accounting for the mutagenicity of 4. In mammalian cells, chlorooxirane,being a reactive epoxide, could be trapped by a glutathione epoxide transferase [31] at a faster rate than the detoxification of chloroacetaldehyde via the less active aldehyde dehydrogenase [32] . Such detoxification of chlorooxirane could
CMA 03231
explain tr.s reported decrease in sulfhydryl level in liver cells during metabolism of short chain halo hydrocarbons including vinyl chloride [31]. Perhaps the lower mutagenicity of chlorooxirane 4 in these bacterial assays, compared to the chloroacetaldehydes, is also attributable to its being detoxified faster. We therefore consider both chlorooxirane 4 and the chloroacetaldehyde monomer hydrate 6 to be the ultimate carcinogenic metabolites of vinyl chloride. Their reactions with DNA causing mutations in Bacillus and Salmonella suggest a causal relationship with vinyl chloride carcinogenesis in human and laboratory animals.
Acknowledgements This work was supported by grants from the B. F. Goodrich Co. This grant
program was initiated and administered by the Cancer Center of the University of Louisville. The Salmonella tester strains were kindly provided by Or. B. N. Ames of the University of California, Berkeley. We also thank George 0. Stratton, Or. and S. E. Yen for their able assistance.
CMA 003232
REFERENCES AND FOOTNOTES
*To whom correspondence should be addressed. 1 Viola, P. L., Blgotti, A. and Caputo A. (1971) Cancer Research 31,
516-522 2 Maltoni, C. and Lefemine, G. (1974) Environmental Research 7, 387-405 3 Creech, J. L. and Johnson, M. N (1974) Journal of Occupational Medicine
16, 150-151 4 Lee, F. I. and Harry, D. S. (1974) Lancet 1, 1316-1318 5 Hefner Jr., R. E., Watanabe, P. G. and Gehring, P. J. (1975) Annals of
New York Academy of Science 246, 135-148 6 Watanabe, P. G., McGowan, G. R. and Gehring, P. J., Annals of New York
Academy of Science, in the press 7 McCann, J., Sinnion, V., Streitwieser, D. and Ames, B. N. (1975) Proceedings
of National Academy of Science U.S.A. 72, 3190-3193 8 Rannug, U.,Johnsson, A., Ramel, C. and Wachtmeister, C. A. (1974) Ambio
3, 194-197 9 Malaveille, C., Bartsch, H., Barbin, A., Camus, A. M. and Montesano, R.
(1975) Biochemistry Biophysics Research Communication 63, 363-370 10 Bartsch, H., Malaveille, C. and Montesano, R. (1975) Internationl Journal
of Cancer 15, 429-437 11 Hayduk, W. and Landle, H. (1974) Journal of Chemical Engineering Data 19,
253-257 12 Walker, G. (1953) Formaldehyde, p. 86, Reinhold, New York 13 Natterer, K. (1882) Monatsheffe fur Chcmie 3, 443-464
CMA 003233
y
14 Harris, G., ad (1955) Dictionary of Organic Chemistry, Vol. 2, pp. 589 and zzs
15 McCann, J., Spingarn, N, ., Kobari, 0. and Ames, 8. il. (1575) Proceedings of National Academy of Science U.S.A. 72, 979-983
16 Okudo, S. and Romig, W. R. (1965) Journal of Molecular Biology 14, 130-142 17 Laumbach, A. D. and Felkner, I. C. (1972) Mutation Research 15, 233-245 18 Vogel, H. 0. and Bonner, 0. M. (1956) Journal of Biological Chemistry 218,
97-106 19 Kada, T. Tutikawa, K. and Sadaie, Y. (1972) Mutation Research 16, 165-174 20 Walling, C. and Fredericks, P. S. (1962) Journal of American Chemical
Society 84, 3326-3331 21 Gross, V. H. and Freiberg, J. (1969) Journal fur Praktische Chemie 311,
506-510 22 Zief, M. and Schramn, C. H. (1964) Chemistry and Industry April 18, pp.
660-661 23 Kappus, H. Bolt, H. M., Buchter, A. and Bolt, W. (1975) Nature 257, 134-
135 24 Hagstrom, A. (1974) Ambio 3, 77-79 25 Voogd, C. E. (1973) Mutation Research 21, 52-53 26 Fjellstedt, T. A. Allen, R. H., Duncan, B. K. and Jakoby, W. B. (1973)
Journal of Biological Chemistry 248, 3702-3707 27 Lehmann, A. (1974) Life Science 15, 2005-2016 28 Barbin, A., Bresil, H., Croisy, A., Jacquignon, P. Malaveille, C., Montesano,
R. and Bartsch, H. (1975) Biochemical and Biophysical- Research Communications 67, 596-603
003234 CMA
20 29 Kochetkov, N. K. Shibaev, V. N., and Kost, A. A. (1971) Tetrahedron Letters
22, 1993-1996 30 Leong, B. K., Macfarland, H. N. and Reese, W. H. (1971) Archives of
Environmental Health 22, 663-666 31 Johnson, M. K. (1965) Biochemical Pharmacology 14, 1383-1385 32 Weiner, H., King, P., Hu, J. H. J. and Bensch, W. R. (1974) Alcohol and
Aldehyde Metabolizing Systems (Thurman, R. 6., ed.), pp. 101-113, Academic Press, New York
CMA 003235
lseries to figures
rig. i. itaoi i Uy or v(ny: W4 1 I wi '
Fig. 2. Survival of Bacillus subtil is MC-1 after incubation with: 7.0 n:M chloroethanol 2 ( + -*) l.CTmM chloroacetic acid ^ (o--o); 5.76 mM (concentra tion based on clIbCCHO) chloroacotaldehyde (453 aqueous solution) 6 and 7 ( c>--1>); 0.7 mM 4-nitroquinoline-N-oxide (0-0); and untreated control cells (o--o). Mid-logarithmic cultures grown in MY-1 broth were incubated with compounds at 37*C. Samples were plated at the times indicated from which viable cell counts were recorded. The mutagen 4-nitroquinoline-N-oxide served as a positive mutagenicity control.
Fig. 3. Survival of Bacillus subtil is strains in the presence of 5.0 r'i (concentration based on CIlK^CCHO) chtoroacetaldehyde (453 aqueous solution) and 7. Cultures were growwnn"to mid-logarithmic phase in MY-1 broth and than incuBated with the chloroacetaldehyde solution at 37C. Samples were plated at the times indicated from which the percent survival was determined. FB-13 uvr*, rec+ (+--+);Hcr-9 her*, rec+ (0--0); 163M wild type (o --o); and MC-1 uvr*, rec" (o-- &).
Fig. 4. Dose response curves with Salmonella typhimurium TfllOO. Sample solutions of known concentrations prepared in UMSO were mixed with 'tester strain culture and soft agar. Plates were poured, incubated at 37QC for 48 hrs, and then score^A for revertant colonies to prototrophy. Chloroacetaldehyde monomer (o --o); chloroacetaldehyde (45% aqueous solution-concentration based on CIH2CCHO) and 7 chloroacetaldehyde dimer hydrate .( >--fi>); chloroacetaldehyde trimer a (--x)i and epichlorohydrin jg(u--o).
003236
JL 0 12 24 3 C M CO
TIME HOURS
CMA 003237
Figu. 2
,x
O
,0
#
*
___I____ CO
Ml MUTES
J.
/ c *l.s
/
TABLE I: Bacteria Tester Strains
A. Salmonella typhimurium LT-2 Tester Strains3
aAll tester strains contain uvrB repair mutations which eliminate the excision repair system; mutations in the histidine operon; and rfa mutations which alter the cell wall by increasing permeability and eliminating pathogenicity.
^The resistance transfer factor,"R" factor,enhances the error-prone recombination repair system thus making the strains more susceptible to mutation [15].
cThe strains susceptible to base-pair substitution contain mutations in the histidine G46 operon and those susceptible to frameshift mutation contain mutations in the histidine operon C 3076 (TA 1537)
or 03052 (TA 1538, TA 98).
Strains
"R" factor1*
Mutation detected0
TA 1535 TA 100 TA 1537 TA 1538 TA 98
base-pair substitution + base-pair substitution frameshift
frameshift + frameshift
B. Bacillus subtil is Tester Strains
aTrp" denotes a requirement for tryptophan; Mit-S denotes sensitivity to mitomycin C.
^hcr+ denotes a host-cell reactivation DNA repair capacity; her" lacks
a host-cell reactivation DNA repair capacity; rec+ denotes a recombin ation DNA repair capacity; rec" lacks a recombination DNA repair capacity; uvr* is sensitive to ultraviolet-induced DNA damage.
Strains
________ Phenotype3
DNA Repair**
168 M IIcr-9 FB-13 MC-1
Prototroph (wild type)
Trp' Trp* Trp",Mit-S
hcr+, rec*
her", rec* uvr*!, rec* her , rec"
CMA 003241
TABLE II, PMR Spectra of Vinyl Chloride Derivatives
Compounds. C1HC-CH20 4
C1H2C-CH0 5
CIH4^C-CH(OH)4* 6
C1H-C-CH-0H Li 0 *
C1H2C-CH-0H
7 '
Solvent CC14
CC14 DMSO-dg
CD-OD-DpO 1:8 3(pD 0.1)
Soeccra, a7MS*0 (0=r!` ' 2.75 (q, CH, 0-1.5) 2.85 (q, CH, 0-2.4) 4.90 (q, CH, >2.4,1.5)
4.00 (d, CH, >2.2) 9.57 (t, CH,, >2.2) 3.50 (d, CH) 9.60 (t, CH2)
3.60 (d, CH,, >5) 4.60 (t, CH, >5)
DMSO-Dg CD,0D-0,,0 1:8
3(pD 20.1)
3.55 (d, CH,, >4.9) 5.05 (t, CHT >4.9)
3.60 (d, CH,, 0-4.5) 4.83 (t, CHT J-4.5)
ch2ci
A
1 C^n'0'x^H-C1 2c
S
cci4
DMSO-dg
3.52 (d, CH2, J-4.7) 5,08 (t, CHT J-4.7)
3.75 (d, CH,, >4.1) 5.45 (t, CHT 0-4.1)
CMA 003242
28
TABLE III: Summary of Mutagen Activity in Microbial Systems
HI = No inhibition of growth detected in Bacillus subtil is MC-1; NR = No increase of revertants in Salmonella typhimurium TA 100 compared to control;+ =active; ++ = very active. Acetaldehyde, a potential metabolite of and allyl chloride, the parent olefin of
were negative in these two systems.
Compounds Tested
Control: 4-nitroquinoline-N-oxide
1 H2-C=CHC1 2 C1H2C-CH20H ^3 C1Hc-C-C00H 4 C1HC-CH--0 ~ L 2J 5 C1HL-C-CH0 6 C1H2C-CH(0H)2 7 ClH,C-CH0H-0-CH0H-CH9Cl 8 (ClH2C-CH0-)3 9 C1H2C-^H-CH20
Bacillus subtllis Repair Assay
++ NI NI NI + ++ ++ ++ ++ NI
Salmonella typhimurium Reversion Assay
++
NR NR NR ++ ++ ++ ++ + t
CMA 003243
. JLC i i
'V CTt
a Si;
Inhibition was measured in min after 24 hr at 37C as described in text; NI denotes no inhibition
Mutaqen
Molarity
cih2c-cho
5
'V
0.100
Chloroacetaldshyda
(45i aqueous solution}
G. 115
ClH-C-CH-CH
i 0i
7
i
C1H2C-CH-QH
0.097
CII12C^0>S -CUjCI Ci!2Cl
8 0.096
cihc-ch2o
4
A#
0.260
C1H92C-Ci H-CH-,2Qj
-9v
0.113
4-Nitroquinoline-N-oxide 0.001 (control)
168M 2.0
NI 1.5
MC-1 27.7 22.5
9.5
Hcr-9 3.7
F3-13 2.7
NI A'IT U
1.5 1.5
-
7.0 NI NI 10.0
14.5
10.0
NI 18.0
6.0 NI NI 15.0
7.0 NI NI 15.0
CMA 003^44
30
TABLE V. Relative Mutagenicity of the Four Forms of Chloroacetaldehyde with typhimurium TA 100
45% Aqueous Soln 6 : 7 50:50
Monomer 5
Dimer Hydrate 7
Trimer 8\#
Molarity
5.3xl0'5 2.7x10`5 1.4xl0`5 6.9x1 O'6 3.4xl0'6 1.7x1 O'6 8.6x1 O'7 4.3x10"7
Revertants Molarity
977 1.3xl0"5 723 6.7xl0'6 512 3.3x1 O'6 194 1.7x1 O'6 120 8.4xl0-7
61 4.2xl0`7 36 2.1x1 O'7 10 l.lxlO-7
Revertants
18 68 88 361 404 238 185 131
Molarity
4.8x1 O'4 2.4xl0-4 1.2xl0-4 6.0xl0'5 3.OxlO'5 1.5x1 O'5 7.5x10~ 3.8xl0*6
Revertants
311 259 193 107
88 30 23 11
Molarity
4.8xl0`4 2.4x1 O'4 1.2xl0"4 6.0xl0`5 3.0x10"5 1.5xl0-5 7.4xl0`6 3.7x10"6
Revertants
144 159 101 39 27
18 12 -0
33<S
VI: Savers ion of S.tyor and bOicniorcnjor *n ^
CG Oy Chi crooxi rone T 'Vi
Broth solutions of $ or ,9 with TA100 were preincubated at 3*C before plating. Duplicate plates were evaluated after 48 hrs at
37"C.* The average number of revertant colonies per plate minus the number of spontaneous reversions were recorded.
Preincubation Tire
0 hr 1 hr 2 hr 4 hr 6 hr
Epichlorohydrin 9
(1.0 rV)
^
185 204 297 202 154
Chlorooxirane 4 (0.26 irM) ^
31 4 6
114 44
CMA 003246
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*"<!
-'.A ' '-
--* " *1 '*,
,4,i" ,
'mS 1'*5.. ' *-
tf.*T7^S* u;V'il . ,.'J*.*** `
- -"' W^K-v'
v KJlV'i' rr.-irr.
iLGedl Felkner
t' iiiWn't' . . * -!'
.
*' .*
"* *- *-
~ " '* '. ""t-4 L--`f4
''
-" * 4
; ............... > -*- *.
, V,_v *>. ^ < ... -.V . -.:
* i. '4, *
CMA 003247
BACTERIAL MUTATION MONITORS FOR ACTIVE METABOLITES OF CHEMICAL CARCINOGENS: B. SUBTILIS ASSAYS FOR MUTATION AND DNA REPAIR
ULDIS N. STREIPS University of Louisville, Louisville, Kentucky ANDREW D. LAUMBACH Food and Drug Administration, Washington, D.C. RONALD E. YASBIN The Pennsylvania State University, University Park,
Pennsylvania
I, Introduction
II. Microbial Assays
A. Salmonella Reversion Test B. Bacillus Repair Assay C. Bacillus Forward Mutation Analysis D. Bacillus Comptest
III. Discussion
References
131
134
134 135 137 137
141
143I.
I. INTRODUCTION
Chem'ical monomers, such as vinyl chloride, styrene, and acrylylnltriie, are of great Importance in many industrial synthesis reactions. They are the fundamental components of polymers used extensively in the economy of the industrial nations. The detection of tumors (e.g., angio sarcoma) in workers exposed to vinyl chloride in the industries of several nations suggested that there was a relationship between this industrial monomer and the development of hepatic disorders (13,40). As a result, both Industry and government have become Increasingly active in research
131 CMA 003248
1 o*>
U. N. Streips, A. D. I.aumbiich,
l L^ODl
iCTiI CLu^s^Li .icily ci extcnsiveij" us*/! ciieuiical com-- ' L`lifTrti'.natcly, the assay." for t'.in.'or production arc time consuming (70) and the number of existing and newly produced chemical formulations huge. Therefore, it is imperative that rapid assays for mutagenicity and potential carcinogenicity be performed to narrow the spectrum of chemicals which should be tested for tumor production in animal systems. Epoxides are generally thought to be intermediates in microsomal, enzyme-mediated oxidation of olefinic compounds (29). As such, chlorooxirane and its rearrangement product chloroacetaldehyde (CAA) (20) were suspected to be the carcinogenic metabolites of vinyl chloride. Several laboratories have confirmed the mutagenicity of these compounds (4,20,39, 42,45,59). Our laboratory also tested the various multimer forms of chloroacetaldehyde, as well as chlorooxirane, and found them to be muta genic (20). It is reasonable to assume that other industrial monomers may also form reactive metabolites upon oxidation. In this chapter we describe several rapid assays, primarily utilizing DNA repair functions as the screening methodology, for the detection of biological activity in known mutagens [ethyimethanesuifonate (EMS) and methylmethanesulfonate (MMS) ] as well as in the oxidation products of the chemical monomers vinyl chloride and styrene. Repair of mutagen-elicited lesions in DNA is important for the survival of affected cells. However, DNA repair has also become increasingly implicated in pathways leading to additional mutagenesis and possibly carcinogenesis (49,30,73). The discovery that certain UV-sensitlve mutants of Escherichia coli are not mutated following UV radiation'led to the hypothesis of error-prone and error-free types of DNA repair (73,75). There are three distinct pathways for the repair of damaged DNA following radiation or exposure to chemical agents (photoreactivation, excision repair, postrepltcatlon repair). The process of pbotoreactivatiou involves the binding of the pyrimidine dimer by the photoreactivating enzyme and the "splitting" of the dimer following the exposure of the enzyme-dimer complex to photoreactlvating light (37,61,60). Significantly, this mechanism of DNA repair does not result in the production of mutations and is therefore error-free (5,74,75). Damaged DNA can also be repaired in the dark via the excision mecha nism (10,69). Excision repair (uvr genes) Involves the enzymatic recogni tion and removal of the damaged DNA followed by repair replication (56). In this process, the single-strand gap produced following the removal of the damaged base or bases is filled in by a DNA polymerase which uses the undamaged strand as a template. In E, coli. the most efficient and accu rate excision repair system requires, among other gene products, a func tional DNA polymerase I (12,24,36). However, alternate pathways of ex cision repair have been demonstrated in cells lacking DNA polymerase I (44, 82 , 84,85). Excision repair is also virtually error-free, although there is a low frequency of mutation which has been ascribed to errors in the alternate pathways of this type of DNA repair (8, 53,74). One of our rapid tests, the DNA repair assay, examines the ability of cells lacking this typo of repair t survive chemical damage (Table 3).
CMA 003249
6 / Bacterial Mutation Monitors for Active Metabolites
133
Phot reactivation and excision repair are processes which rest re the integrity of the damaged chromosome prior to the replication of the DNA. Following the replication of the DNA, integrity can still be restored by the proccss(cs) of postreplication repair. Postrcplication repair is believed to involve the filling of gaps left in daughter strand DMA following the repli cation of damaged DNA (32, G2). The closing of these single-strand gaps Is accomplished by at least two types of mechanisms in JS. coli (83). First, a constitutive type of postrcplication repair has been shown to involve recom bination (22,23,03). Second, one or more types of postreplication repair are inducible and their mechanisms of action are unknown (04,05). Post replication repair has an error-prone element (0,35,05,73,74), which is ail inducible, independent minor pathway. Specifically, mutants of E. coli lacking the products of the recA+ and/or lexA+ genes are unable to induce this error-prone repair system (48,75). All postreplication repair in E. coli is dependent on a functional recA+ gene product (08) while Inducible postreplication repair is also dependent on a functional lexA* (exTA*) gene product (64). In addition to error-prone, inducible postreplication repair, recA and/or lexA mutations prevent the Induction of prophage (9,18), Weigle (72) or UV reactivation, and W mutagenesis (15,48,54), the induction of recA+ gene product (21,26,27,47,64), the Inhibition of exonucleaae V (43), as well as other physiological changes following the Inhibition of DNA repli cation (09,74). The pleiotropic effects of these mutations led Radman (58) to propose the SOS hypothesis. This theory contends that damage to DNA and/or the inhibition of DNA replication results in the release of a signal which simultaneously activates various functions which aid the cells and/or prophage In survival (74). Therefore, error-prone repair Is the result of an efficient but Inaccurate repair mechanism which is induced in an effort t prevent cell death.
Based on the observations of certain inducible phenomena, the presence of an SOS system can be assumed in nonenteric bacteria (28,30,87,76,86), in lower eucaryotes (51,57), as well as in mammalian cells in culture (7, 14,34,41). It is important to note that the components of SOS systems appear to differ from species to species. Specifically, an Induced DNA modification system has been found in Bacillus subtilts (76). whereas in Haemophilus influenzae. W reactivation has been demonstrated although error-prone repair is not present (28,33,67). Thus, there appears to be significant divergence In the composition of SOS systems.
In mammalian systems the relationship between the mechanisms of DNA repair and mutagenesis is not as readily obtainable as in the prokaryotes. However, there do appear to be analogous mechanisms of repair in the two systems. Specifically, chemical damage (00) as well as .photochemical damage (11) of DNA can be repaired by mammalian cells.
Recently, Interest has begun to focus on the possible effect of inducible SOS-likc systems on carcinogenesis (49,74). In the tester systems devel oped by Ames and his colleagues (1,2,40), most of the carcinogenic agents tested have been shown to require a functional error-prone repair system
CMA 003250
i;m TJ. N. Su-ci: ", A. 0. I.nuir.b.ich, U. , YnMAr.
in order to generate mutations in the bacteria (-10). A phage induction func
tion has been proposed for their system (?i). In addition, aflatosin lb a;-J
--nitrctjLiiito 1 iuc^a --oxiclc \i-tiO'**.*u carcinogenic agci.L.s)
l.i'iucc pre[.i.']^e
X and therefore activate the bacterial SOS system (25, hi). Moreau ct a!.
(49,50) developed a tester system for carcinogenic agents which utilizes the
induction of prophage X. Based on their results, they have suggested that
an SOS-like system, including induction of proteases, exists in eucaryotes,
and that the activation of this system can lead to cancer. If this theory is
correct, a model system in which precocious activation of SOS functions
occurs should be a sensitive tester for potential carcinogens. The bacterium
B. snbtilis possesses many of the desired prerequisites for this type of sen
sitive tester system.
It has been demonstrated that when B. subtllis differentiates into its com
petent state, SOS functions are precociously activated (70,77). In addition,
competent B. subtilis ceils have enhanced sensitivity to UV irradiation (55,
77, 80). This enhanced sensitivity is the result of the Induction of defective
prophages in the competent bacteria (Refs. 77 and 77a). Removal of the
defective prophages and/or the inhibition of SOS induction eliminated the
enhanced sensitivity of the competent cells to UV energy.
We have included this review to substantiate our rationale In utilizing
several types of repair assays, each measuring a different step In the re
pair process, as a part of our battery of rapid assay systems. It is evident
that bacteria have several methods for repairing both UV-induced and chem
ical damage to DNA. Therefore, assays which measure for the Induction of
error-prone repair (SOS) or for the necessity of repair (our series of re
pair assays) represent valuable information when considering the biological
activity of potential mutagens and/or carcinogens.II.
II. MICROBIAL ASSAYS
A. Salmonella Reversion Test
The mutagenic capability of the postulated active derivatives of the chemi cal monomers vinyl chloride and styrene, as well as ethyhnethanesulfonate (EMS) and methylmethanesulfonate (MMS), was examined using the Salmo nella tvphimurlum tester strains described by Ames (1)' using methodology already published by McCann et al. (45) and by our laboratory (20,39) (Table 1).
Chloroacetaldehyde (CAA) was prepared, purified, and analyzed bv prevl ously reported techniques (20). Styrene oxide was prepared by treating styrene in methylene chloride with 1.2 equivalents of M-chloroperbeuzolc acid at room temperature for several days. The solution was washed successively with aqueous NaSOjH and aqueous NallCOj, then dried and evaporated. Both EMS and MMS were obtained from the Aldrich Chemical Company (Milwaukee, Wis.).
CMA 003251
Table 1. Bacterial Strains Used tn These Studies
Relevant
Strain
repair genotype
Source
S. typhimurium TA100 uvrB (R factor) B. Ames
B. subtilis GSV1025
B. subtilis MC-X
B. subtilis GSY1627
recAl recB2 recD27
C. Hadden
C. Hadden C. Hadden
B. subtilis VUB214
recD27
c. Hadden
B. subtilis BD224 B. subtilis HA10G B. subtilis VUB133
recE4 recF7 recH342
c. Hadden c. Hadden c. Hadden
B. subtilis RUB827
polAS
R. Yasbin
B. subtilis FBI 3 B. subtUis HC-9 B. subtilis GSY1641
uvr her mtc-41
C. Hadden
c. Hadden c. Hadden
B. subtills 168W
wild type
A. Laumbach
B. subtilis RUB818
wild type
R. Yasbin
The assays with the S. typhimurium strain TA100, an indicator for base pair substitution mutations (45), revealed that all four chemicals had con siderable mutagenic activity (Table 2). Our laboratory has shown previously that the chloroacetaldehyde consists of several different forms, all muta genic in this assay (20). None of these chemicals caused significant rever sion with strain TA98, a framesht(t indicator.
B. Bacillus Repair Assay
The repair assay, using various repair-deficient strains (Table 1) of B. subtil is. has been described by our laboratory (20,39). This is an indirect mutation assay, modified from the procedures described by Kada et al. (33). As discussed in the introduction to this chapter, when a mutagenic agent
Table 2. Mutagenicity of Chemical Monomers Assayed by Salmonella
TA100 Reversion__________ l Concentration in soft agar
Average number
Compound
laver. mM/plate
revertants/plate*
Chloroacetaldehyde
0.10
456
Styrene oxide
0.10
620
Methylmethanesulfonate
0.05
956
Ethylmethanesulfonate
0.10
295
Spontaneous revertants have been subtracted.
cm. 03252
I L-L-t O-V
126 U. N, Strcips, A. 0. I.uumbnch, H. E, Yasbin
repair the;
IT tcell is unable
to yMpi'cs:s tue repair ciip.n.jtlit;., - ;:..i,iiy oi cu, .j -.via not survive.
Thus, a measure of the* biolugirn! reacivuy of a chemical is to test it
against several strains, one being wild type for repair, the others being
deficient in one of the repair systems. If the wild type strain survives hut
any of the repair mutants do not, the chemical is assumed to be reactive
(see also Chapter 4).
In Table 3 we show the reactivity of CAA, AIMS, EMS, and styrene oxide
against a scries of repair mutants of B. subtilis. First of all, styrene
oxide does not appear to be reactive in any of these assays. This suggests
that over a wide spectrum of concentrations tested, styrene oxide does not
cause damage to DNA, which must be repaired by the available repair sys
tems. Even when these tests were performed with cold incubation (see
Chap. 4; nsfs. 22 and 62), a procedure which increased sensitivity to
CAA threefold, there was no discernible reaction with styrene oxide. On
the other hand, all forms of CAA (20), MMS, and EMS were quite reactive
in this system. However, these compounds affected only' strains which
Table 3. Effect of Chemical Monomers on Hepair-Assay with B. subtilis
Strain GSY1025
Relevant repair
genotype
recAl
Growth inhibition, mma
Chloroacetald ehyd e, Styrene oxide,
0.1 M
0.1 M
13.5
NI
MMS, EMS, 0.1 M 0.1 M 14.5 8.1
MC-1
recB2
11.3
NI 13.0 6.4
GSTTG27 recD27
11.5
NI 11.2 4.S
VUB133 recD27
NI
NI NI NI
BD224 HA106 VUB133
recE4 recF7 recH342
8.8 6.1 NI
NI 16.4 6.1 NI 11.5 7.2 NI 3.0 1.5
Hcr-9 FB-I3
her uvr
NI NI
NI NI NI NI NI NI
GSY1641 mtc-41
NI
NI NI NI
168W
wt
NI NI NI NI
growth inhibition was measured in millimeters from the edge of the disc to the first evidence of growth (radius). Values are an average of seven experiments. Inhibition clue to toxicity, as measured on wt cells (168W), has been subtracted from these values.
Note; NI = no growth inhibition.
CMA 003253
were deficient In the type of postrcplication repair known as recombination repair. Moreover, only specific recombination genotypes recA. recB. recE, recF. and one strain of recD were affected by CAA, MMS, and EMS. One strain of rccD. recH, as well as the excision repair-deficient mutants (her,, uvr, polA) were Inhibited slightly (EMS and MMS) or not at all (CAA). All strains were confirmed to possess the recombination deficiencies by transformation and transduction assays (19). These results suggest that CAA, MMS, and EMS may cause similar lesions, all of which require for repair certain components of the recombination repair pathway. In this regard, 4-nltroquinollne-l-oxide (4NQO) reacts identically In this system (Laumbach and Streips, unpublished data).
C. Bacillus Forward Mutation Analysis
-An additional procedure for determining the mutagenic capability of a chem ical compound is to examine its ability to cause forward mutations. This test serves the same purpose as the reversion assay described in Section II. A. Both are direct tests for mutation capability. However, the response Is less limited for the forward mutation systems.
Cultures of B. subtllls 168 wild type (Table 1) were subjected to a 15-min exposure to CAA, styrene oxide, MMS, and EMS at various concentrations. The cultures were washed and allowed to incubate for 16 hr to express mu tation to streptomycin resistance. The cells (0.1 ml) were plated on tryptose blood agar base (TBAB) plates for total viable count. Similar plates were overlaid with soft agar (0.8% agar) containing 1 mg/ml dLhydrostreptomycin sulfate to determine the number of mutants. The results from thin i experiment are shown in Table 4. It is evident that CAA, MMS, and EMS
` Table 4. Induction of Mutants Following Exposure to Chemical Monomers
i Chemical
Treatment
Total
number bacteria*
Total Mutations Relative mutant per 108 mutation
colonies cells frequency*1.
Chloro' acetaldehyde
0 5 mM
6.0 x10 5.5 X108
2.4 70.8
0.4 12.9
32.3
1 Styrene oxide
0 5 mM
7.0 X10 6.6 x 10
3.1 10.2
0.4^ 1.5
3.8
` MethyIraethanesulfonate
0 S mM
6.0 x10 5.4 X10
2.4 85.8
0.4 15.9
39.8
Ethylmethanesulfonate
0 5 mM
7.0 X10 5.2 X10
3.1 68.3
0.4 13.1
32.8
aB. subtills 168 wild type cells were used in all these experiments. ^Relative mutation frequency = # mutations per 10** cells no treatment
# mutations per 10s cells with treatment
CMA 003254
IMS o Sereins, A. i). I.aumb&eh, <*>V i'-. Y:>s!j*p.
are strong mutagens in this assay. Bpichlorohydrin, a methylene homologuc
S:yr;i:o oxi-t shewed very v.-or.
'1 f*** 1 * 4 ' k * ' ? |* * m4! " * 4r-Cfcv ***** "*c
iL C L v . w * l. .iltvhttt kbOvi c%w i .3 >;v>u^
:::r.ir.;ucr! further in this svsterr..
D. Bacillus Coinptest
'3. subtilis strain RUB827 (Table 1) was grown to competence using the pro
cedure previously described (79), then exposed to DNA which had been
previously Isolated from strain RUBS1S as described by Yasbin (78). After
25 min of incubation, followed by 5 min additional incubation with 100 ug/ml I
of deoxyribonuclease I, the competent culture was centrifuged (15, OOOg for
1 min) and resuspended in minimal salts for UV Irradiation (75,77) or in
G1I2 (79) for treatment with chemical agents. The cells were exposed for
30 min to the chemical agents before they were plated on appropriate media. |
When needed, microsomal activation mixture was added to the competent
j
cells and chemical agents according to the procedures of Ames. McCann,
and Yamasaki (2). The total number of viable cells was determined by colony J
growth on minimal media with glucose, supplemented with all the amino acids
(20 Mg/ml) for which the bacteria are auxotrophic (79). The number of
transformants were determined by colony growth on the same minimal
media which was lacking either tryptophan or methionine.
Significantly, only 20% of a B. subtilis culture achieves the competent
state (81). Therefore, In a "competent" culture of B. subtilis. 80% of the
bacteria are noncompetent. The competent and noncompetent members of
the culture can be separated by their growth on selective media following
transformation. Thus, the number of noncompetent bacteria of strain RUB-
827 can be determined on minimal media supplemented with both tryptophan
and methionine. The competent cells can be calculated from the number of
transformants (the number of colonies formed on minimal medium lacking
either tryptophan or methionine) (52).
The precocious activation of the SOS system in competent B. subtilis
makes thes'e bacteria more sensitive to SOS-inducing factors than non-
coropetent bacteria (Refs. 77 and 77a). This enhanced sensitivity is due
to the fact that the resident prophages are induced at lower doses in the
competent cells. In Figure 1 the data are presented for an experiment
Involving the UV Irradiation of a competent culture of RUBS27. The en
hanced sensitivity of the competent cells was readily visible. This enhanced
sensitivity can be expressed as the percent of transformation obtained after
each fluence of radiation. If the sensitivity of the competent cells and the
noncompetent cells to UV were identical, then the percentage of cells trans
formed should remain constant, independent of UV irradiation. However, if
the competent cells are more UV-sensltive, then as the fluence Increases,
CMA 33SS
G / Bacterial Mutation Monitors for Active Metabolites
133
Figure 1. Survival of the total population of strain RUB827 () and of the competent portion of the culture (o) following UV irradiation.
the competent cells (as represented by the transformants) should be killed at a greater rate than the noncompetent cells. In Figure 2 the relative transformation efficiency is shown at the various UV fluences. As the fluence increased, the relative transformation efficiency decreased. The same types of results were obtained when the carcinogenic compound MMS was added to the competent cells (Figure 2). However, the mutagenic, but not carcinogenic, compound, MS, did not produce a decreasing transfor mation efficiency with increasing dose (Figure 2). Thus, this assay appears to be highly specific for only those components which activate the SOS sys tem. * Chioroacetaldehyde, styrene oxide, and several other potential car cinogenic chemicals are being examined In this system at the present time.
Bacterial strain RUB827 was chosen for this assay because previous results (77) had shown that the poIAG mutation enhanced the sensitivity of this bacterial strain to SOS-inducing substances. Compounds are considered potentially carcinogenic when the relative transformation efficiency (the
CMA 003256
Figure 2. Relative transformation efficiency (RT) of strain RUB827 follow ing exposure to various concentrations of MMS () and OfS (*} as well as following exposure to various fluences of UV irradiation (o). The RT is calculated by dividing the percent transformation at a given flucnce or con centration by the percent transformation at 0 fluence or concentration.
percent transformation of the treated sample divided by the percent trans formation of the untreated sample) is 0.05 or less.
This novel B. subttlls tester system measures the toxicity of agents as well as the ability of these same agents to induce the SOS system. Also, the Cbmptest identifies the concentrations at which the compounds have toxic and SOS-induclng capabilities. The main advantage of this assay is that it apparently distinguishes between substances which are mutagenic and those which activate SOS functions (potential carcinogenic compounds). This property of the Comptest can be noted readily when the relative activities of EMS and MMS are compared.
CMA 003257
t
C / Bacterial Mutation Monitors for Active Metabolites
141
III. DISCUSSION
In this chapter we have described a battery of microbial (particularly B. subtil is) rapid tests for the assay of mutagenicity. The known mutagens EMS and MMS were used as standards In all these tests. In addition, we have also Initiated a progressive study of industrial chemicals and their oxidation products using the described test systems. The initial results for chloroacetaldehyde and styrene oxide, the oxidative products of vinyl chloride and styrene, respectively, have been presented.
In all of the assays, except the Comptest, both EMS and-MMS were highly reactive. It Is interesting to note that EMS was not active in the Comptest, although MMS showed a high level of activity. This finding becomes highly significant when the carcinogenic properties of EMS and MMS.are examined. EMS is not carcinogenic, whereas MMS is a potent carcinogen (17,52). Thus, on the basis of these preliminary results, it seems promising that the Comptest may distinguish between carcinogens and noncarcinogenlc mutagens. We are presently expanding this test to examine a whole battery of chemicals, including chloroacetaldehyde and styrene oxide, to verify this prediction. Since the Comptest specifically examines events associated with SOS induction, It may discriminate for chemicals which induce the error-prone repair systems. Such chemicals could Include all the carcinogens. In this connection, our laboratories have also initiated the interferon induction inhibition (III) test (Ref. 3a). Interferon is an antiviral agent produced by mammalian cells and whole animals in response to viral infections. Preliminary studies in other laboratories have suggested that Newcastle disease virus (NDV) induced interferon production could be inhibited by pretreatment of cell cultures with known carcinogens such as benzoljoOpyrene (16). We have confirmed and extended these observations to include EMS, AIMS, styrene oxide, and other known carcinogens. Our study (double-blind) has demonstrated that styrene oxide and MMS are active in this assay, but EMS shows no activity. This mammalian (including human cell) rapid assay may mea sure for SOS-like events in eucaryotlc cells. Among these events could be the induction of protease, which we postulate could inhibit .interferon induction In virus and polynucleotide-stimulated cells. Furthermore, several known carcinogens are active in this system, whereas noncarctnogenic analogs are Inactive (Refs. 3, 3a, and 16).
An overall comparison of the various microbial tests performed In ur laboratories Is presented in Table 5. It is evident that a composite evalua tion of many assays must be made when considering the biological activity of a chemical. This is shown by the variability in reactions of styrene oxide. It is Interesting to note that this chemical is essentially nonreactive in the Bacillus tests performed so far, yet It is mutagenic In the Salmonella
test and very active in the in assay. If this chemical is also inactive In the
CMA 003258
112 U. N. Struips, A. D. Laumbach, R. E. Yasbin
Tabic Composite .Yub
Chemicals
Salmonella
s: v.Y.err.'.ca4 lonomers
Forward Hcprir assay mutation
Chloroacetaldehyde Styrene oxide
+ ND + ND
T
+
+
Methylmethanesulfonate
+
+
++
Ethylmethanesulfonate
+
-
++
^Results are expressed as (+) positive in the assay performed, (-) nega tive in the assay performed, and (ND) not determined. Styrene oxide was weakly reactive (Table 4) and must be considered to have borderline activity in the. forward mutation assay (t).
Comptest assays, then it must be considered that styrene oxide may not enter Bacillus cells. Alternatively, styrene oxide may not elicit the types of repair we are examining in the B. subtilis system. An additional point , must be made in regard to the repair assay. Two mutants with recD27 j genotype gave dissimilar results when tested with reactive chemicals. Slnct they both were found to be Rec", we must assume that one or the other of these mutants does not have the recD27 genotype.
Chloroacetaldehyde has been highly reactive in all assays done to date and must be considered as the probable metabolite of vinyl chloride, re sponsible for the biological effects'elicited by this industrial chemical. This conclusion has also been made by other laboratories testing vinyl chloride metabolites (4,20).
In conclusion, we have described one rapid assay (Comptest) which may have the capability of detecting carcinogens. In addition, we are refining a rapid mammalian test (III), which also may identify carcinogenic chemicals These two assays, along with the other tests described in this chapter, pro vide a battery of rapid procedures for screening a large number of chemi cals for biological activity. As such, they are potentially valuable In our overall research programs dealing with environmental pollutants and indus trial monomers.
ACKNOWLEDGEMENTS
We are grateful to Dr. John L. Wong for valuable discussions and for pro viding the chemicals used In this study. We appreciate the critical appraisal of this contribution by Dr. R. J. Doyle. We wish to thank Camille Jones, Mary L. Kinnaman, Carole Kolb, Rosemarie Michl, and Donna M. Crabb for excellent technical assistance and Drs. C. Hadden and B. N. Ames for bacterial strains. This work was supported in part by grants from the
CMA 003259
G / Bacterial Mutation Monitors for Active Metabolites
143
Kentucky Tobacco Health Research Institute, the Manufacturing Chemists Association, and B. F. Goodrich Company to U. N. Streips and the Uni versity of Louisville Cancer Center, and a grant from the Department of Energy (EP-78-S-02-4964) to Ii. E. Yasbin.
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CMA 0326l
( / 1 Pictorial Mutation Monitors for Active MotaiKtliU'S
143
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CMA 003262
JounuL or BtntmtMT, Jum 1919, p- 915-OtZ 0031-9199/79/DMBIA/OMB.OO/O
VoL US.No.3
Selective Association of the Chromosome with Membrane in a Stable L-Form of Bacillus subtilis
SARAH HOROWITZ.' RONALD J. DOYLE.1 FRANK E. YOUNG,' and ULDIS N. STREIPS" Deportment ofMicrobiology and Immunology, Schools ofMedicine and Dentistry, University of Louisville, Louisville, Kentucky <0232/ and Department ofMicrobiology, Schools ofMedicine and Dentistry, University
of Rochester, Rochester. Nttr York 14842'
Received for publication 11 January 1979
A stable L-form (Sal-1) of Bacillus subtilis was found to have retained a markedly modified chromosome-membrane association when compared to intact cells. The membrane-deoxyribonucleic acid complex of the L-form was similar to that of its parental strain in quantity and stability. Genetic analysis of the L-form membrane-deoxyribonucleic acid complex revealed enrichment for markers close to the replication origin, but not for internal markers, indicating preferential attachment of the origin of chromosomal replication to the membrane. These results are in close agreement with those found for the parental bacterial form. In contrast, the replication terminus region was not preferentially attached to the membrane, of the L-form. even though it is enriched in the bacterial form. The association of the chromosome with the membrane at the replication terminus doea not appear to be necessary for cell growth and separation, but because the L-form divides aberrantly, it may be one of the factors required for normal deoxyribonucleic acid segregation and aeptation.
Interaction between the chromosome and the ceil surface has been well documented in pro caryotes. A stable attachment of the chromo some to the cytoplasmic membrane has been demonstrated in gram-negative as well as gram positive bacteria (15,22). The DNA in the memhrane-DNA complex was found to be specifically enriched for the replication point and for genetic markers close to the origin and terminus of chromosomal replication (10. 12, 19. 24. 27, 28, 34. 35). This attachmant was proposed to aid in the segregation of the newly repeated chro mosomes and in cell division (14). Further work with Escherichia coli (9), and in our laboratories with Bacillus subtilis (3,26), has demonstrated a stable attachment of the chromosome to the (rigid) cell wall as well as to tht cytoplasmic membrane. The DNA attached to the cell wall in B. subtilis was found to be enriched for ge netic loci near the origin and terminus of chro mosomal replication (26). The chromosomemembrane-cell wall complex has been proposed to be held together by qacific binding proteins (5, 9, 11, 29, 30). This complex may creata ani apparatus functional in cell division processes.
Kesenrch with procaryotes lacking cell wall has demonstrated that the genome of Myco plasma gallisepticum is also associated with the membmne. showing specific enrichment fur the replication (>oim and possibly the origin of chro mosomal replication (20, 21). Electron micro
graphs have revealed the presence of chromo some-membrane association in protoplasts and unstable L-forms of B. subtilis (23). However, to date, genetic characterization of the chromo some-membrane complex in procaryotes with out call walla has been lacking.
In this report, we describe studies on the DNA-membrane association in a stable L-form of B. subtilis, Sal-1 (.'Hi). This organism requires 1.2 M NaCl for stabilization, doea not have cell wall polymers, and does not revert to the bac terial form (6). Moreover, this L-form appears to have lost cell division control and undergoes aberrant cell division (R. W. Gilpin, personal communication), as do other stable L-forms (7, 33). Therefore, the L-fonn becomes a good model to test our hypothesis that loss of control in cell division may be due to the loes of one or more of the components in the cell division complex, such as the cell wail and proteins as sociated with the peptidogiycan. 'Hie present study offers the first evidence that a stable In form retains attachment of the chromosome to the membrane. Furthermore, this attachment is specific only for the origin of chromosomal rep lication. The region for termination of genome replication appears to have no specific affinity for the surface of this L-form
(This work i* n part of the dissertation to he submitted by S. Horowitz to the Graduate Fac ulty of the University of Louisville in partial
91S
MA 003263
916 H0R0WIT7. KT AL.
J. Bactemol-
fuHlHmont of the requirements for the Ph.D.
degree.)
MATKKIAI.S AM' MKTHODS
Bacterial strains. The It. xubttlix strain* used in thin study an Iwlr-d in Tsbli- I. Wc thank H. Yi.-biknwn for (train TL8132. N. Sucolut for strain Mti8u5ul6, J. Copeland for strain BCl'JJ. N. Harford for (trains BD170, BD202, VUB45, and YUfUl. S. Phillips for (train QB922, and -J. Kane for strain B1W2. All strains were maintained on trvptose blood agar l>os (TBAB) (Oifi'o Laboratories, Detroit, Mich.). The stable L-form, Bel-1, kindly provided by R. W. liilpin, is a derivative of B. tubtiUr BRIS1 (Jti) and retains thametBiO marker (1>. The L-form was main tained by passage in stabilising liquid medium (below*. The parental (train. B. nubtilm BR151 lyx-3 trpCS mrtfilO, waa transformed to promtmphy for lyn-1 and trpC2 with B. rubiilin wild-type 168 DNA to maintain the same tusotrophic background as the L-form, and was designated aa (train BUIJOi.
Media and growth conditions. The L-form, Sal1, was grown in 19 ml of Sal-1 medium, s modified glucoee minimal medium described by Spizizrn (25! with 0.016% (wt/voll MgC!j-6H.O (instead of 0.02T MgSOi-7HjO-1.2 M NaCI) for stabilisation. 0,05% ca sein hydrolysate, and 50 pg of L-methionine per ml. The culture waa shaken in a rotary weter bath (New Brunswick Sciamiflc Co.. New Brunswick. NJ.) at 37*C and 190 rpm. B. xubtdix BUL404 waa propagated in Sal-l medium without NaCL under the asms growth conditions. Both cultures ware grown for two or more generations in the exponential phase in the presence of deoxyadenoetne (200 pg/ml; Sigma Chemical Co., St Louis, Mo.) and [2-,',CJthymidine (0.1 pCi/ml, 5-1 mCi/mmoi; Schwarx/Mann, Orangeburg, N.Y.). Cell growth waa monitored on a Klatt-Summerson colorimeter with filter no. 54.
Lysis. The L-forms were harvested by centrifuga tion at 5,000 rpm for 5 min and then washed twice in
cold NCP buffer 10.01 M sodium citrate. 0.09 M
K-HPO.-3H-0. and 0.04 M KH.-l'Oi. adjusted to pH 7 4 112|i. which contained 1.2 M NaCI The evils wen* then suspended ui a small volume t NCP plus l.J M NaCI butler anil iy.-u.-d by utanotu.- shock .lur tc ;luaddition of NCP butter without NaCL The resuituig lysate was a four- tu eightfold concentration the original culture, and contained a final concentration of 0.1 M Nad The B. whtUis BUL404 ceils were har vested and washed as Sal-1. but in NCP buffer without
NaCL then concentrated four- to eightfold in NCP, and lyasd by tha addition of lyaoxyme (0.5 mg/ml; Worthington Biochemical Corp., Freehold, NJ.) for S mm at 37*C. The lysate was then adjusted to 0.1 M NaCL Both lysate* were either left untreated, or wetc sheared for 30 s on a Vortex mixer (Fbh*r Scientific Co.. Springfield. Mass.) set at position no. 6.
Renografin gradients. Linear (0 to 38%) Renogrefin density gradients (Ranografuv-76, from Squibb
and Sons, Ine., Princeton, NJ., in NCP plus 0.1 M NaCI buffer) were prepared by the method of lvarie and Pine (12). Bampiaa (1.0 to 1J ml each) of the Lform or the parental strain lyaataa were layered onto 30-ml cold Renografin gradients. and tha gradiante were centrifuged in a Beckman L285B uftracentnfuge at 29,000 rpm, 2*C brUh, name an SW28.1 rotor. After centrifugation, 1.2-ml fractront were collected into sterile tubes. Sampfae of thaaa fractiooa (0M la 0.50 ml each) ware counted in Multisoi acinrillation fluid (laolab Inc., Aluon. Ohio) in s liquid adnriUatoon
counter. Tha remaining volume of each ot the peak fractions waa meinterned at 4*C far transformation experiments.
Transformation experiments. The procedures
for tha development of competence and transforma tion were thine of Boyian et aL (2). Auxotrophic strains of B. subtiU* (Table 1) ware grown in GMI (2) at 37*C in a New Brunswick gyratory incuuator shaker at 250 rpm. Cell growth waa monitored on a Klett. Summerson colorimeter (filter no. 54) until tha cenwtion of logarithmic gramtth. After 90 min of further
Depletion
Tahlx 1. lidsfarsiMued Osnerype
DtrivttNB VMMI
Sahl (stable L-fana> BR7 BR151 RUB783 BLTL201 BUL320 BUL401
BUL404 BUL406 BULBS
BUL706 BUL7M BUL714 BUL717 BCL720 BUL728 BUL728
mttBlO ItuAS trpCS trpCS b*-3 mttBlO ItuAS mtfBlO hitAI purBS ItuAS purAlS hitAI ItuAt mttBlO thr-S HUAI ItuAS gUA29S
MttBlO mttBlO ItuAS IhyA thyB
ItuAS mttBlO fyt-3 ItuAS mttBlO hitAI pyrAl ItuAS mttBlO cytAU hitAI ItuAS purAIS mttC3 ItuAS MttBlO trpCS purBS ItuAS eitICS ItuAS trpCS lyn-3
RW. Gilpin B.E. Reilly B. E. Reilly This laboratory
This laboratory BUL714 x BD170 thr-S ftpCT QB922-*UA2S2 trpCS X TLSlStt-ituAS thjA thyft
tsm'
BR151 X Wlfii*
BR151 X Sal-1*
IVTT-trpCS thjA thyB x MsfafaBparAlf ItuAS mttBS"
BR151 x RUB7S3* RUB783 x VUB45-AmA/ oryCApyrAf
RUB783 x BDn-cyaA/4* BUL20: x VUB41-trpCS mttC3* RUB783 x BXYXn-trpCT _ BC123-.'mC2 ei'KS x Mu8u9ul*
RR151 x TIAI-i'
* Obtained by congression (17); general notation; recipient celt * donor DNA.
CMA 003264
Voi_ 138.1979
incubation, the cell* were atinted tsi-.fnid i'iro GMli CJ) and incubated an additional SO min. at which time the cultures were mnmmalK cumpetent. Peak trac tions from the Kciuigriilin itrailu tu.-. scrvi-il ic (lmuir DNA. These fractions were diluted in Spiziivns min imal salts solution to avoid saturation and to reduce the concentration of the Kenofraftn (8). The compe tent cell* were incubated with the ONA for 30 min at 37*C in the incubator shaker. Sample* (0.1 ml each) were plated in triplicate on selective media and incu bated at 37*C. Transformants were enumerated after 48 h of incubation. Each genetic marker was analyzed for enrichment from 3 to 16 times to attain statistical validity. In general, selection for transformants waa done on giueoae-minimal agar (251 supplemented with the appropriate amino acid* and base*. Selection for the citKS transformant* was on minimal agar plate* which contained 0.13- sodium lactate (J. T. Beker Chemical Co.. Phillipaburg. N J ) instead of glucose Selection for thyA transformant* was by incubation at 46*C on plats* without thymine (18). The thyB trans formant* were sensitive to growth at 46' C without thymine and were evaluated by subtracting the num ber of transformant* {thy*) at 46*C from those at 37*C
(18). Selection for fUA2S2 trsiuformantr waa on glu-
cone-minimal agar in the absence of 400 mg of glutamic acid per ml 14).
RESULTS
Distribution of labelod DNA on Renogrofln gradients. To determine the presence
L-FORM MEMBRANE-UNA COMPLEX 917
of a rr.embrane-DNA 'm-DNA) complex in the t.-furm, a culture of Sal-1 was grown in Snl-I medium, and its I)NA wn unilArmlv l.-ih-led with i-"Cjthyntuiine. The doubling tunc of the L-forms, as determined by Klett absorhuncu units, was approxtniately 2 h under these growth conditions. The L-forms were washed and then lysed by osmotic shock. For comparison, the parental strain BUL404 was also grown and labeled under similar conditions, having a dou bling time of 40 min. The parental strain was also washed and then lysed by exposure to ly sozyme (0.5 mg/ ml) in hypotonic solution. A sample (1 ml) of each lysate was immediately layered onto a 0 to 38% linear Renografin density gradient. The remainder of each lysate was sheared by blending in a Vortex mixer for 30 s, and then 1.0- to 1.5-ml samples were applied onto Renografin gradients. The gradients were centrifuged and collected, and samples were as sayed for radioactivity (Fig. 1). In the absence of shearing, the L-form DNA formed a distinct peak at the lower part of the gradient (Fig. IA). The penk corresponds to the membrane-at tached DNA (m-DNA) peak that was found in the unsheared lysate of the parental strain BUL404 (Fig. la). When sheared, part of the In form DNA formed a slower-sedimenting peak (Fig. IB) which corresponds to the free DNA (f-
Fra. L Distribution of the tnbetsd DNA /tarn the L-form. Sat-l. on Renografin gradients. The L-forms were gratae, labeled. waehed. and lyeed cu described. Vnsheared (A) or sneered (B) lysates were sedimented on 0 to 38% Renografin gradienta. fraction* were reflected and counted for recovered radioactivity. In ait tampion, 90 to IOC/% of the input radioactivity was recovered. For comparvion the parental strain. B. subhli* BVL404. woe grown, labeled, and waahed under similar conditions, lysed by exposure to lyeatyme (0.S mg/ mil is hypotonic solution, and the unsheared (al or sheared fbl lysates were sedimented on Renografin gradients as above. Sheared Iseatet demonstrate membrane-attached (m-DNA) and free (f DNA) nucleic acid
CMA 0326s
918 HOROWITZ ET AL
4. BaCTZSUH..
DNA) peak of the parental strain (Fig. lb).
However, a significant proportion of the labeled DNA of the L-form was retained in the m-DNA
I*eak as firmly attached DNA (Fig. I Ft), ns in the t\rental tvirren'v slr,;in 'Fiji th) The p-'C'-rn
of DNA distribution foi the L-form, as weli as the parental bacterial form, in unsheared and sheared lysates is in close agreement with that described by Ivsrie and Pen* for B. subtilis 168T~, using Renografin gradients (12). To com pare the distribution of the L-form labeled DNA in the Renografin gradients to that of its parental strain, the results of several experiments were pooled, and the average percentage of DNA in each peak ( the standard error of the mean) was calculated. Approximately 80% of the la beled DNA in the unsheared L-form lysate is attached to the membrane (m-DNA) (Table 2). Upon shearing for 30 a, approximately 30% of the DNA remained firmly attached to the mem brane (m-DNA), whereas about 35% of the DNA appears ss free DNA (f-DNA). These results are statistically not different from thoae found in the unaheared and sheared lysates of the parental
strain BUL404 as determined by an independent t test (Table 2). This observation suggests that the L-form has retained an m-DNA complex physically similar to that of the bacterial form.
To compare the stability of the m-DNA com plex of the L-form to that of its parental strain, both lysates were subjected to different shearing times, tnd the resulting DNA distribution on Rsnografin gradients was observed. There was no significant decrease in the percentage of mDNA for both the L-fonn and the parental strain when sheared for tunas ranging from IS s up to 60 s (S. Horowitz, PhJ3. thesis. University of
Louimrills, Louisville, Ky,, 1979). We, therefore, routinely used a shearing time of 30 s for the experiments described below.
Genetic analysis of membrane-attached DNA isolated from the L-form and its pa rental strain. The DNA bound to the mem brane wee used in transformation tsay* to de termine the genetic composition of the m-DNA
Taeu 2. Effect of shearing dm m-DNA complexes
from Urn L-form, Sol-1, and its parental strum, B. subtilis BUL40*'
*mm
Treatment of lyeate
m-DNA <%
f-DNA <*>
Sal-1 8UUM
No hearing MWir No shearing
Shewed'
SUa s 2.78 31JS lot 8100 1JS
348SUS
IUSSL7T U.0S 1-0S
13.41 083 34.31 xsas
* The pmedurae lor th* xaparaem at m-DNA rad f-DNA end lie --ys far mdioecUvtty w m isnftel in tlw legend is Fig. 1.
* The lyewi new xhearxd tor 30 tone Votes surer xei at position &
complex from the L-form and compare it to the
profile found in membrane-associated DNA from the parental strain BU1.404. Different
chromosomal markers, chosen to provide an
analysis of the entire chromosome, were exam
ined, and the membrane enrichment indexes (MEI) were calculated by the method of Sueoka and Quinn (27). The marker leuAS was used as a standard in these calculations. The average MEI values for each marker tested ( the stan dard error of the mean) are presented in Table
3. For statistical analysis, s two-factor analysis
of variance with repeated measures on one factor was run. The between factor was the 13 genes
we had examined. The within factor was the
parental (BUL404) versus L-form (Sal-1) con
dition. The Duncan range test was used for post
hoc comparisons to find markers among which a significant difference occurred (31). The ge
netic and statistical analyses revealed that the
DNA attached to the membrane in the L-form was enriched for the markers purAlB and
cysA14, which ere doss to the origin of chro mosomal replication (16, 37), but not for the internal genes huAI, purBB, thr-S. leuAS (stan dard), metC3, pyrAl, fys-3, and tkyA (Table 3). These results showed preferential attachment of
the origin of chromosomal replication to the membrane in the L-form. In this regard, the Lforra m-DNA complex was not statistically dif-
Tsaut 3. Genetic analysis ofm-DNA isolated from the L-form. Sal 1, aad ita parental straw. B. subttli*
817.404
Genetic nsiiker examined*
purAlS
rysAH hixAl purBG
thr-S leuAS m*tC3 pyrAl ly3 thyA trpCl gUA292 thyB eiiKlS
Sai-I MET
1.74 0.11 1.78 0.17 088ai3 1.10 0.12 1.17 0.11 1.00 081 0.10, 185 044 i.i7 a 19 1.07 0.02 ass o<w l.l 0.0W 082 009* 0.96 aor
HI L4M MET
1.35 0.19 187 0.23 080 a 12 186 0.14 1.11 0.13 1.00 a920.U 1.06 0.14 1.10 021 1.40 *0.17 187 Oil 1.80 0.18 1.90 0.48 2.20 084
* Recipient strsinn used in these experiment* ware BUL201.330.401.302,706, TOO. 714.717,720,726,728. RUB783. and BR7.
`Calculated by the method of Sueoka and Quinn /
(27). ME! - (UfleuASi in m-DNAl/f(j//ew't*1 in fDNA], where xisthe number oftremformants for any marker tested, and leuAS is the number of transform ants for the standaid marker leuAS.
' P < O.nl when compared to RULI04, by analysis of variance.
CMA 003266
voi.. vx. io:a
L-FC1HM MK.VnltANK.ONA t'OMl'l.KX 913
:t"ru "Torn tha m-DNA ccr.plsx :r.a OATe-;.L
iirnin 3UL404 (Tibls ;). la contrast. tne repli cation 'errrmus ra*j'"a cf 'hi L-fcrm wr,.:
found to be preferentially attached to the mem brane. The terminus markers trpC2, gUA292. IkyB, and citKS were enriched in the m-DNA complex of the bacterial form. BUL404, but were not enriched in the L-form (Table 3). The MEI cf the genetic markers tested in the m-DNA complex of the L-form and its parental strain are presented in relation to their relative posi tions in the bidirectional replication map of B. subtilis in Fig. 2. As a control, incubation of the parental lysate in the presence of 1.2 M NaCl did not bhnf about loss of the specific membrane attachment of genetic markers close to either the replication origin or the terminus.
Genetic analysis of m-DNA isolated from
ti'-s hybrid 3CL4u5. Sine.* the L-form c;>pe?.rrt! to h,r- e lost the spin, iAc aira; hr.itof
:ht Tcrminu.! i.i the membrurie. .1
t;n,.... i.inr
in fVaniine whether a ehi,onui'*Mt,...l Iran nt-ni
from the terminus region of the L-form would
he able to regain the specific attachment when
placed in the parental, bacterial form. Therefore, we constructed a hybrid. Bl L405, which is a derivative of the parental strain BH1SI. The hybrid contains the internal marker lys-3 and the terminus marker trpC2 from the L-form (Table 1). Strain BUL405 was grown, labeled, washed, lysed, and sheared as described above for the parental strain BUL404. Both m-DNA and f-DNA were isolated on Renografm gra dients. and genetic analysis was performed. The internal marker. lys-3, of the hybrid. 3L"t,40S,
was not enriched in the membrane and had an MEI value not statistically different from that
of the parental strain, BUL404, and the L-form. Sal-1 (Table 4). The terminus marker. trpC2, was enriched in the membrane of the hybrid, BUL405, as it was in the parental strain. This
enrichment, indicated by the MEI values, was significantly different from that found for the In form trpC2 gene which was not enriched in the membrane.
DISCUSSION
This study demonstrates that Sal-1, a stable L-form of Bacillus subtilis BR151, has retained an attachment of the chromosome to the mem brane. In Renografin gradients, thin attachment was similar in sedimentation, quantity, and sta bility to that of the parental bacterial form in both sheared and unsbeared lysate*. Further more, these results were in dose agreement with the attachment found in another strain of It. subtilis (12). Our findings represent the fimt description of an m-DNA complex in a stable I,form. and it appears that the permanent loas of cell wall polymers did not prevent chromoMimemembrane association. Such ao attachment may be a universal feature of all procaryotes. Several laboratories have described both specific and
PlC. 2. MSI far the genetic markers examined from m-DNA of dm L-form, Sal-1, and its p-irentat Mtom. B. eubttlis BUL404, correlated to the map poeUion of thorn morhora to B. unbuilt 168. The mop pooitaam far Urn different genes were calculated from tho bidirectional replication mop of B. wtbtilia 168 of Lepeaant-Kc/tlorooq it oL (Iff and Young and Wlfmi (37). Tho MEI Haloes (* standard error of tho
moot) on taboo from Tabl* 1 (A) m-DNA from Urn L-form. Sal-1; (8) m-DNA from dm parental strain. BUL404. Tho dotted line represents the areas of expected membrane enrichment of generic markers, bared on our results and those in the literature (10, 38).
Taiu 4. Generic analysis of m-DNA isolated from B. subtilis BUL406
Gsnene marker BULMSMEI BULtOeMET Sal-1 MET
lys-3 l.U 0.08 M0 * 021 1.17 t 0.19 trpCS 1.44 o.ir U70.tl' 0.98 0.08
" Recipient strains used in (been experiment* were BULK*. BUL72S. and BR7.
`The MEI values were taken bom Table 3 for enmparwon.
' P < 0.01 when compared to the MKI of the trpC2 marker in Sol-1, uaina an independent t test.
CMA 003267
920 HOROWITZ ET AL.
J. Bactmiol.
nonspecific attachment of the chromosome to the membrane (10. 12. 13, 24, 27, 28, 34, 35). To determine whether the m-DNA complex from the L-form contained specific regions of the chromosome, we used samples of peak fractions from the Renografin gradients in transformation assays and calculated membrane enrichment in* dexee (MEI) (Table 3). Such genetic analysis revealed that the origin of chromosomal replication was preferentially attached to the mem* brane in the L-form, as in the parental bacterial form. In contrast, the specificity for the attach ment of the terminus region had been loot in the L-form. This finding indicates that the two sites of attachment may be chemically and physically independent and may involve different binding proteins, as haa been suggested previously (29, 34). The persistent binding of the origin region also suggests that this specific attachment to the membrane is of critical importance. The propor tion of m*DNA (32%) found in the L-form, de spite the loss of terminus attachment, could be explained by more extensive association of the origin, when compared to the parental form. Alternatively, radioactive counts due to nonspe cific attachments (13) may mask the loss of radioactivity from terminus detachment
Since the L-form, Sal-1, is known to divide aberrantly (R. W. Gilpin, personal communica tion), the loes of specific attachment of the ter minus region to the membrane may be a con tributing factor to the loss of division control in this organism. The integrity of the DNA-mem* brane-protein-cell wall complex was proposed to
be crucial in maintaining normal cell division (26). Moreover, dynamic terminus attachment to the membrane in correlation with the call cycle has been proposed to play an important role in cell division control in B. subtilu (32). All these factors lead to the speculation that loss of terminus attachment may be critical in the loss of normal DNA segregation and cell division processes.
Several possible factors could have been re sponsible for the lorn of specific terminus attach ment to the membrane in the L-form. The most probable are: a change in the affinity of the DNA in the replication terminus region of the chromosome for the membrane or for specific binding proteins; the permanent loss of cefi-Wall along with a disappearance of an outer surface site for terminus attachment (26); a loss or al teration of binding proteins which may aid in the specific attachment of the terminus to the membrane or cell wall (5. 9, 11, 29, 30); and, finally, the presence of a high concentration of salt (1.2 M NaCI) over many generations in the growth medium of the L-form, which might af
fect the terminus-membrane attachment, but not the origin-membrane association.
Results from genetic analysis of the hybrid BU 1.405 (Table 4) appeared to negate the first possibility and indicated that no change in the affinity of the L-form terminus region DNA had occurred, because the trpCZ locus from the Lform was membrane-enriched when integrated into the parental strain. Nevertheless, this ar gument cannot be folly ruled out, since it is possible that only a very small fragment of the L-form trpC2 region entered the BR151 strain-
enough to make it tryptophan-independent, but not enough to make a significant change in the affinity of the terminus for the surface. It is also possible that the specificity of terminus attach ment is determined by discrete sequences within the terminus region of the chromosome rather than by the whole region itself (35). The trpC2 fragment, which originated from the L-form, although found in membrane preparations, may not be one of such specific binding sequences.
Partial loss of the specificity of DNA-membrane attachment in the L-form could also be due to the inactivation of binding proteins from the membrane and/or the cell wall in the chro mosome-surface complex. Such proteins could have been lost or altered as a consequence ofthe removal of the cell wall, or during continued growth in the presence of high salt. Alterna tively, it is possible that a mutation occurred in one or more of these proteins, because the Lform has undergone silent end apparent muta tions sines it was isolated (1). Furthermore, the profile of the membrane-protein composition (6) and the membrane-lipid composition in the Lform (S. Horowitz, Ph.D. thesis) was signifi cantly different from that of the parental bac terial form whan both were cultured under the same growth conditions.
In addition to the foregoing studies on the DNA-membrmne complex from the L-form, we alao have generated information which better defines the extent of the specific membrane at tachment of the chromosome in B. aubtilis. The specific attachment of the origin, as examined in transformation experiments by use of the markers purAie and eyaAN, statistically con firmed that the cyaA14 gene was part of the origin-membrane complex (28), as is the purAlS marker. In the terminus region, the thyA locus had an MEI value of 1.40 which appeared to indicate that it was membrane enriched.-'as noted by Yamaguchi and Yoahikawa <35. How ever, it did not paaa statistical analysis, and therefore must be considered as an internal marker. Thus, it appears that the thyA locus may be the most proximal marker to the termi-
CMA 003268
Vol. U8.1379
i. ri.KM MKM BltAN'K-UNA COMl't.KX 921
tin;* rtfii:in un the ""..n" -.,le o; ;na rhrotii|,`ji*i!*
. , tri. 'i .l/Vi ,i~ i". 1
i !!i'irnu.n,iv,r i,
- ..if J .11 .,1 >' i .if
t,'pC2 gnu. 'in'.:
''.i.'i;. cOiiMC-ereil \i ',t
utciiiji m.irk r iU,
2bi, was significantly *nnchert in the membrane,
and may oe rhe beginning of tne terminus region on the other side of rhe bidirectionally replicated
chromosome. The /y*..7 marker, which is near to
trpC2, wan not membrane-enriched in any ex
pel iments. The observation of N'euhard et <d.
ild), describing the temperature sensitivity of thymidylate synthetase B in B. xubtilix, enabled
us to screen Separafeis for IhyA and thyB
markers, thus adding the thyB gene to the list of
terminus loci enriched in the membrane. The MEI of the different terminus markers were
increased as the distance towards the terminus
of replication was decrea*>*d, suggesting stronger chromosomal attachment near the terminus
point. The hisAl and purBS loci which have
appeared to he somewhat enriched in some of
the previous reports (10. 24. 27, 23) were not
found to be membrane enriched in our study,
and belong to the internal region of chromo
somal replication. Tlte attachment of the chromosome to the
membrane, as demonstrated in the present work
with strain BUL404, seems to be less extensive
and leas specific (lower enrichment values) thsn
the attachment of the genome to the bacterial
cell wail as reported by Streips et aL (26). These findings could indicate basic differences between
the in vivo chromosome-surface complex < in
cluding ceil wail) in bactene and the compiex
isolated after cell wall removal.
ACKNOWLEDGMENTS
W. thank R. W. Gilpin far prwidini the L-fo-m. SM.|. und for hatpAil Senvw. W* ! wpw our srautuitr m r. Hon fur lwtpu with thv rtittMinJ noiyvot.
This writ wm auppunet ft* Naonnol Utnmn Founrtniim piM PCM7S-0M03 to R.j.0 anl tl HA, by a flam frwv tftMknulonunne Chtmaua Animuon to U.N.S., and by liwuluuonal Anancaa Cancer Suet*** snot 1N-IIIR fnm the (Jimmy of LoufcwiUeiiSH. and U.NA
UTERATt'RK CITED
1. HatUngar V* anil 1 I' 1 ount 1*171 Traiufnnhi in i
of Bartthi* .nr/... imU.-mm, alslitv nf d'-.- t U
laeirir and m l.-i**t*. .* L-furma or prat* i i . .
Darnmil.
X Bwyiaa, K. 4. N. It Mawdrlaaa. I). Brook*, and E
Yeung. 1*72. Raaulauon of tha bonanot t nl mil:
Mafyaat af a nuiam uf Bmctlbm rntmlm
m
biimiwhi i of 100,-ho*- and. J Bactariul. HSU . ..1111
X Brown. W. C. B. J. Doyto. aad U. N. Stroifw. lets
Cv-'Thi "* of vanuro proesdumo D* muaiii pruloeia and midoit arlda from call walla of fleet I*'*. auS-
Hiis. Pmp. BioctWfTL SMtT-tSS.
A Prdond.-T. R. A, J.-A, Lrpnant, J. Lopaaonr-Kridn-
rovo. A. BlUonlL M. Sum--. aad f. Kumi. 1."
Comuiwtion of a kit of teftmnm mm tor mpid
rn 8-JCiitus aubtmi luH
E.i.-,*cn
I.f N SireipE, V. a^. C
(,. . n,
11. iiiid ,M. Mnn^fU-lU,
'*inrin *> . f'/% su/ifi/1. .J IV -nol
. -t
' (dlpin. K. W , K. K, Youna. and A. N. rhatifrjn-. I'lTTI.
i hornt tmiau.in u( a -tattle l. turm of Hu, ill,,. .hOu/l.
IM 1 tlaiirnol U3:idii-t9W.
t.tlpin, K. W.. und S. S. Nagy. lyTO Titm-*lin*se* iihuft*^-
f^jihv of llavr/ln* Hidtth*
rvplKBMOjt m iutuh|
fnrtlium -I Hartcnvi,
H HnodrO, C., And E, W* Nesler.
[jrirLa:,on ol
cvlU in th* BacUfu* suhtth* trAnj>tof7naoon
A\w*n. J Hav'vno^.
^ Hridnth, H, Gw und W, L Ots#n* MJ"1* DtytxiTiUHHia
i iru ji id
complrif* frtfm A.\/7irrt'7fa nr/f A
coatt>le*-4mn ific pfiK^n -inal iu
rtmuiou tor
ttar NUbtluy of ih complt*. J. C4| Hioi 67:444->-4M0.
. i Hy. K. Jm M. A. 0*SuiiivnBa K. Hvwafd. And N.
diMokA.
M*mhrn tnwnctatnin "if ^Ttgtn irrmi*
uuA. and nrpUiauon !Ofk in tiactlluM -uitHiii*, p.
In D aSchl4HMn<*f f*d Mirmhol.)<v -- |?7#i Am-ri* En
S'Kiety tof MicfomoloAy, Wathin^ton. D.C,
; i. ImadJL Sw L E. Carroil. and .V 5*i*f>fc*a 1976, DNA-
mtmnrant
in BnctUu* nthnlt* p ! IS-1*22. In
D. Schlrttfungtr (ed.>. Muifobmino -- I97k, Amvriian
Socifty For MkrehivliHiy. Whinftoiio D.C.
12* Ivan*, R. Dm tnd J. J. RtfM. 1970. Auociauoa of rh#
BactituM -4tknfi-i (hftwtmmmi with thv c#il mmnhrnnr
rMilutun of trve and Ixiuod dcosynbunwclfic acvl on
Renoffrafin ^adicnu i. Bocitnot. t04;9J9-HV)
11 Ivarit. R. Dm tnd J. J. Pm*. M71, .\weciativn nf mnny
-**cion of th# Ritctllum MiiXiU* chfomomni* with tho
c*U mombronr J SiH ttnoi. U4^?1^7.
H. Jacob, F-. 3. Bmaor, aid F. Cusia. 1931 On tbi
r*4ilaboa of DNA rtptkotion in boctorio. Cold vSpnnf
Harbor Syrop. QwoaL BloL U m-Zdi
t l LothowHx. R J*. and M. ScbMcbur, 1973. Th* jul-icHmipfM uf ' hi* .Miritwinl t hfownim tu thr coll nwtn<
umnv. Lm ifov Cyiol.
i Up*aaat>Kv;dNfnva, J,, 4.-A. L*iwmm, J. Walk*. Ay
Btlloulta and R. Ilfdoadaf. 197.% Rovomm ,*f iho.
unktift map uf lUmtlu* mtohlt* liiA indicAttudn for^
nfiifUmv .*f iho i ttfnfnflMiflr, J
,
` Nnivr. IL W, M. Sdbaftr, and J, Lodri borf. IWt.
m fJNA tfonofor rlutr of miw am*
rt*rm*d with ommour hmnjrmlMMi m Aonf/mi umbttiim,
i>- 43:521-^51.
* Nrunnfd. Jm A. fL Mow, 1* Schiack, and R "naowien
wit I97M Two rhymidvloio aynthotm** m Bnciitum
Pnn- Natl, And So. U.S A. 79; 1194-119M.
^ Punter. D. \-- aad D. A, Ulaoer. 1971. rhvwnwwwmol
Rii-t of DNA*movih*Ofie uurhMWt ua Enckvruhtm
n,it_ J. Mol- HmM. a7:!S3-tL
<4ujtioi, U. Cm and 4. MuDofT (973. Mombrjiw iw>
rmiiain oi the domynhomnieic odd ynowon-pnint
*M>n in .Wvc//<ijmwo
J. BwctefwM. 1U:
, .7.v*:n!i
iMiinlaA D. CM and 4. ManiMT. 1973. DooivnhmHH lm'
u id ymhew m wnrbrnonwh twain
J Aoairnnl. MS:tl7-IJU.
Ryaer, A. 19NM, Ajwot:ia(iua of the madeiie and the mm>
hmne uf harifnr. a inurpbuliwai udy. SoctormL (lau Mt ibJLS
11 Hyter, aT and O. B. Laodhai 19M. Mun*ho4^w*J
wiiidv of the otiorhmefli of nud^od u> momhmne in imkiUa, petHOfilinii* and rovwrtino pnnufMaM* <M lUtviihw wuh/i/uk p Ilu-I2;L M-L H. lUde iU. Munibiid pnHi>fMu4s -phenifdaiUB and I. Inw I'he 'Villtane*
- .uwl Wilkuw V *f. HuHinmn* .. Snyder, R* V, end F. B. Yowa. \im Am mum
CMA 003269
922 Hoitowrrz kt al.\
J. Bactfriou
between the chromosome and the cytoplasmic metn-
bnui* in Barilla* subtilt*. Btochtm. Bwphy*. Rat. CummuA. J8::i44-.T6i
J* "tpixixrn. J. 1948. Tranafurmation f bHshetnicolly defi
cient strain* of Baetllu* mbtih* by deosyrriionocleat*. Proc. Natl. Acad. Set U.S.A. 4:1072-107*. jt. Strcips. (J. N., R. J. Doylt, W. D. Crabh, M. A. Court ney. and V. S. C. Fan. 1976. Sifiuficsnct of DNA attachment to <b* c*U surfme of Baeilhi* tabula, p. SW8, tit A Porwle*. R. Lopes. and M. Espinosa led.). Modern trends in bacterial trmiWormstton and tranefectioo. Elnrar Pram. Amsterdam. 27. Sueoka. N, and W. C. Quinn. 1968. Membrane attach ment of the chromnaMn* replication origin in Baattu* Jibuti*- Cold Spring Harbor Symp. Quant. Biol. 33:
696-704. 28. Sueolta. N, R. J. Bishop, N. Harford. K. H. Keaneu.
A. O'Sullivan, and W. G. Quinn. 1973. Chromosome
replication and ceil meubnlism m Baetllu* itublili*. p. 73-87. In Z. Vanefc. Z. HoMalek. and J Cudlin led.). Genetic* of industrial nucrwtfeaiaina, Academia, Pra-
|U*. 29. Sueoka, N- and J. M. Hammer*. 1974. laulation of
DNA-membran* complex in Barilla* Jibitiln. Proc. Nail Acad. Set USA. 71:4767-4791. 30. Toyoda. H- K. Yamaguchi, and H. Yoahikawa. 1978. Chromosome membrane association in Barilla* nubttlu. IV. Kurtbar purification of ONA-membrane com plex by uain* a combination of centrifugation and eter-
trophoraoia J. Bacterial. 138:799-802.
31. Winer, B. J. 1971. Sm*l* factor experiments bavin* re
peated measure* on the same element*, p. 26i-;. In
Statistical principirs in experimental design, 2nd rtl.
McGraw-Hill. Book Co., New York. 32. Wineton. &, and T. Matsushita. 1976. Protein synthaaw
and th* release of the replication terminus from the cell membrane in Baetllu* tuOrt/u, p, 123-127. la O. Schlossrnier ted.), MicrebiolOfy--1976. Amenran Society (hr Microbiology, Washington, O.C
33. Wyriek. P. B-, and H. J. Rogers. 1973. Isolalion and
characterisation of call wall-defective variants of Bacrf. ha nubtili* and Barilla* luhmformt*. 3. Baettnol 118:446-465.
34. Yamaguchi 1C. and K. Yoahikawa. 1973. Topography of chromosome membrane junction in Barilla* *uhttit*.
Nature (London) New Biol 244:204-206. 34. Yamaguehi, K- and H. Yoahikawa. 1975. Association
of the replication terminus of the Baetllu* nubtili*
chromoaoow to the cell membrane. J. BecterinL 124: 1030-1033. 36. Young, F. E- P. Haywood, and M. Pollock. 1970 laolation of L-fbrms of Baetllu* mbiiti* which grow io liquid medium. J. Bacterial. 102:867-870 37. Yotwg, F. t, and G. A. Wilson. 1976. Rivwisei of the linkagi map of Raalba tubtili*. p. 686-703. fn G. 0. Pieman led.). Handbook of htoebanustry and molooilar biology. 3rd ad., section B. *oL U.CBCPiani.Clevelind. Ohict
CMA 003270
14
lUpraiMd (twa Mkmbiolafy UMO C ISM Anwncaii Society far MicTotaoiofv
Genetic Analysis of DNA-Surface Interactions in Bacillus subtilis
ULDIS N. STREIPS. SARAH HOROWITZ, and RONALD l. DOYLE
Department of Microbiology and Immunology. School of Medicine. University of Louisville. Louisville. Kentucky 40232
In a paper which has provided the foundation for many productive experiments in molecular biology aad bacterial cell division, Jacob, Bren ner, and Cuzin (11) proposed the "replicon" model to explain some of the mechanisms of DNA initiation and replication. One major con cept of their proposal was that portions of the cellular genome were attached to the cytoplasmic membrane. That assumption made it possible to account for proper segregation of the genome into daughter cells concomitant with cell growth.
Subsequently, research in several laboratories demonstrated that the chromosome of various bacteria was indeed attached to the surface. Moreover, the attachment was at the origin and terminus of replication and at the replication point, as well as at several nonspecific points along the chromosome (4. 5, 9, 13, 17, 18). The specific association of the chromosome at sites involved in DNA replication reinforces the con cept of a causal relationship among DNA-surfacc attachment, cell division, and chromosome segregation. To study this relationship further, we have investigated DNA-sutface attachments in Bacillus subtilis under conditions in which normal cell division and DNA segregation are disturbed.
MEMBRANE-DNA COMPLEX IN A STABLE L-FORM
A stable L-form from B. subtilis, sabl, has been propagated in liquid media since 1989 (19). The L-forra grows in the absence of any ceil wall and is stabilized by 1.2 M NaCl. sai-i and its salt-independent derivative, sig-l, have been shown to divide aberrantly, producing progeny with altered cytoplasm and DNA contents (6.7). In this respect, these two L-forms are similar to other L-forms isolated from B. subtilis (14). We have used sab! as a model for an organism which has lost proper cell division and DNA segregation control.
To determine whether the DNA-membrane at tachment remained intact in these aberrantly dividing cells, we isolated DNA-membrane com plexes by use of Renografin gradients (9). The complexes were then assayed for DNA content
by transformation, and membrane enrichment indices were calculated (9). As shown in Fig. I, when compared to spheroplasts (panel A), the L-form (panel B) retained enrichment for genetic markers close to the origin ofreplication, purA16 and cysAld. Several internal markers were not enriched in either sample. However, selective enrichment for genes close to the terminus of replication, such as trpC2, gltA292, citK5, and ihyB, was found to be lost in the L-form but not in spheroplasts. It is attractive to speculate that this loss of replication terminus attachment con tributes to the loss of division control in the L-form.
There are several factors which could have contributed to the loss of replication terminus binding (9). Among the most probable alterna tives are the absence of a cell wall or the pres ence of high salt (1.2 M NaCI) in the growth medium. If the loss of cell wall contributed to the dissociation of the terminus of replication from the surface, then it follows that the cell wall contributes to the makeup of the normal DNA-surface complex.
CELL WALL-DNA COMPLEXES
To examine the possibility that the cell wall is involved in attaching the chromosome to the surface of B. subtilis, we isolated cell walls at various stages of growth and examined the preparations for transforming activity (I, 13; R. J. Doyle et a!., submitted for publication). Not only did isolated cell walls possess trans forming activity, but the transformation was specifically enhanced for genetic markers around the replication origin and terminus (Fig. 1C). The extent of enrichment in the cell wall differs from that observed with membrane-DNA com plexes. Thus, hisAI, pyrAI. and sacA were en riched in the cell wall samples, whereas the same markers were not enriched in membrane-DNA complexes (9. 13. 18). In contrast, cysAid. a marker which was shown to be membraneenriched. was not found to be specifically at tached to the cell wall (9. 13. 161. The signif icance of these differences is not obvious at the present time. There is an overall symmetry ap-
284
CMA 003271
v strips. HOROwrrz. and doyle 285
t
Fig. 1. Genetic analysis ufsurface-DNA complexes in Bacillus Jubtilis. Genetic markers on the chromosome
of B. tubtilis and its L-form. sal-1, were examined for enrichment in membrane and watt preparations (9, IS).
Represented are the enrichment maps for spheropiast membratte-DNA (A). L-form (sal-1) membrane-DNA
(B). cell wattmsxociated DNA (C). and membrane-DNA from 1.2 M NaCI-trrated cells ID). The genetic map of
B. subtilis is that presented by Young and Wilson (20). Each marker is designated as enriched I>. nonenriched
(0), or not examined <'). Replication origin (0). replication terminus IT).
parent in the cell wall-DNA profile (Fig. 1C), which is not present in the membrane-DNA preparations (Fig. 1A and B). This loss of sym metry could be due to changes in the topography
of the in vivo DNA-surface complex after re moval of the cell wall. Along with these altera tions it is possible that prolonged growth in the absence of a cell wall could also result in
CMA 003272
286 DNA-SURFaCE interactions
the diviociiition of the isrmtnus from the mem
br^ne
EFFECT OF SALT ON MEMBRANEONA COMPLEXES
An alternate possibility for the loss of attach ment of the replication terminus by the L-form is the presence of 1.2 M NaCl in the growth medium of this organism. A high concentration of salt may destroy the integrity of the surface-DNA complex. The effect of salt on morphology has been documented (2. 12).
We grew B. subtilis BUL 404 {meiBlO) in 1.2 M NaCl and isolated membrane-DNA com plexes at various intervals. In Fig, ID. we show the memfcrane-DNA profile from ceils grown in 1.2 M NaCl for 120 min. It is obvious that growth in salt dissociated the replication termi nus from the membrane in the bacterial strain. Recent experiments suggest that replication terminus dissociation occurs within the first 30 min after addition of 1.2 M NaCl to the culture growth medium. Moreover, after 120 min of growth in 1.2 M NaCl. the entire population of ceils has assumed abnormal morphological char acteristics. suggestive of changes in cell division control. Thus, we have been able to emulate the L-form state of replication terminus detach ment and induce abnormal cell division by grow ing B. subtilis cells in high salt. Presumably, plasmoiysis has occurred in these ceils. There fore, it is attractive to postulate that the replica tion terminus site may be labile to plasmolytic detachment of the membrane from the wall. Such removal could destroy the integrity of this surface-DNA site. In contrast, the replication ongin-surface complex appears to be inviolate to the effects of high salt concentrations. Origin of replication binding has also been maintained in the L-form. This suggests that the replication origin-surface complex may be of primary and vital importance for ceil survival.
DISCUSSION
On the basis of the foregoing scries of ex periments, several conclusions can be drawn concerning the surface-DNA complex in B. subtilis. First, the in vivo complex contains not only the chromosome and membrane, but also pepiidoglycan. Second, of all the binding sites, the attachment of the origin of replication is of primary importance. This attachment is main tained in all samples assayed to date. Third, the replication terminus attachment appears to be labile to high salt and perhaps prolonged growth in the absence of the cell wail. Thus, the L-form and ceils grown in 1.2 M NaCl have
lo-t pri-lvrcnii.il attachment at the terminus .a icplicituin Icrminus Jii.ithTcnt and 'vim.ii morphology cun be restored utter removal ot the 1.2 M NuCI (S. Horowitz et ul.. submitted for publication!. Finally, once the attachment in the terminus region is lost, cells are observed to have altered morphology and division patterns.
These data suggest that the DNA-surface com plex is a vital structure for the procaryotic cell and has a dynamic role in the maintenance of the cell cycle. The complex may regulate not only DNA replication but also DNA segre gation and cell division events. If the complex is disturbed, then aberrancies in cell division processes occur. It is possible that information for the proper maintenance of the complex and its functions resides m the proteins found in both the cell wail and cell membrane (2. 8. 10). Such interactions, however, remain uncharacterized at the present time. The ability to manipulate the constitution of the DNA-surface complex and the morphology of cells leads to the pos sibility that the individual functional com ponents may be isolated and studied.
ACKNOWLEDGMENTS
We thank Joey Dobbin for uchmcai iwviki m a pan ot (Nil reiearch. Tarry Whita prowdod vskuiMe tb-cu-tem liunnf ih* preparation at the mnuicnpt.
Thu manreh was uippuned hy National Scianc* Founda tion (rant PCM 7B-4M0) to R.J.D. and U.N.S.. by a (ram from tha ManuNctunnc Chomnts Allocution to U.N.S.. and by Institutional American Cancer Society (rant 1N-IIIR from the University ot Lotnivtlle to S.H, and U.N.5.
LfTEXATURE cited
I. arm. W. C~ R. J. Deyta, and li. N. Stretpa. IWT*. Companion of vanoui procedure* for removing pro tein and nucleic ictdl from cell with of SmilUn ruMRf. Prep. Biochem. *r*T9~0.
L Deyta. R. J,, U. N. StrUpa. V.SC Faa, W. D. Bnuo. fi. MaOtey. nd J, M. MandWd. I9T7. Cell wall protein in Jenifer ,shrift*. J. BactenoL IPiMt-ltl.
I. EMaa. T.. a. Wmd, nd H. Rapm. IVTS. Formation of cad wail poiyman by reruno proioptnMt of Juriifs* lithraifurmu. J. BacuriW. IM4Z3-41Z.
4. ritlWIa. W. I9T2- The ON A/membrane fraction of Pnewmnmrre* contain a DNA rapiicanoo cumplia. J. Moi. Bioi. EfcJBl-JSr.
J. Ganna. A. T.. and J. Liiirhrr(. IMS. A cad awmbranebound fraction of bacterial DNA. Bipchtm. Smphyv Rss. Common. iaU24-*35.
4. GBpto, R. W.. Md S. S. Nnz- IV7* Time-lapac phutuprapny of fanffat raAnfrv L-form fipdtptiop at liomd medium J. Baclcnoi. iZTtlOlR-IUZI.
7. GBpia. . W,, aod S. K. Htwriio. IV7A. Adaptation of a liable L-form uf Hutilltii tsAniit to (lummai -ell* medium wunout omiumk UiiMimrv J. Uuctcnui. IJJt nat-aee
x. Harmon, j. M.. aap H. W. TaOer. IV77. Alicrad accamahuina of a mimhrana protein unupia to a new bfano^tuxynbunucIcK seal cumptea ia adau iietuium mutant of dui/hn >*An*i J. Sacieriui IJOII22-I-12"
CMA 003273
STRE1PS. HOROWfTZ. AND DOYLE 287
9 Ham*!. S-. I. J. Hash. E.1. 3 nun*. and l . V Streips. I9"9 Scievlivc association ol the ehriunosomc Kith the
membrane in a siahlc I 'hem of Hunllu* -iihnli* J Baeteno) t5-w;;. ID Imada, S.. L. Cerruti. and N. Sucnka. 1976. Membrane DNA complex in Bmitlm lubhlu. p 116-122. /n 0 SvMewnfer led.). Mieruhwlo*> --197*. American Society foe MkrobioJoty. Wachinyion, D.C. 11. Jamb. F., S. Immr, and F. Curia. 1963. On the reyulaturn of DNA replication in bacteria. CoM Sprint Harbor Syrnp. Quant. But. 2*329-34*.
12. Kaiaka. t. 1931. Electron itucrtneopic obsemuons on trowui* and dividint proloplaais of Bacillus megntrnum. J, Gen. Mtcrgbhd. 63:199- 202.
13. Leibawltx, P.. and M, Scbnaetar. 1975. The attachment of
the bactarial chriMWKime to the cell membrane. Im.
Rev. Cytol. 41:1-2*. 14. Rytar. A- and O. E. Landman. 1964. Electron micro-
scope itudy of the reiattonahip between meatMomc loir and the stable L-statc (of protoplast state) in BacUlus subulls. J. BactcrioL 6*456-467.
I). Stnipa. U. N, R. J. Dayle. W. D. Crab*. M. A. Caattney, aud V. J. C. Fro. 1976. Sifmhcancr of DNA attachment to the ced luta of BaciUms subnlis. p. 63-6*. In A. Ponotes. R. Lopez, and M. Eapinoaa led.). Modem
trends in bacterial transformation and transfcctiiat.
Elsester-North Holland PuNishin* Co.. Amsterdam. 16 tsueoha* N., H. J. Hu hap. .V Hsrfart, K. H. Kennett, A*
O'Solliiaa. aad 1%. (i. Qaina. 1973. Chromosome rcpii cation and cell metabolism in Butillus lubulii, p. 73*7. In Z. Vaneh. Z. Hoilllek. and J. Cudlm ltd.i. Genetics of mdustnal aMcreorianiims. Acadcnua.
Prifuc. 17. c--rtj-- N,, tad IV. Qslsa 1961. Membrane attachment
of the chromosome replication onyin in Bacillus sabriffs. CM Spnn* Harbor Symp. Quant. Bui. 33*93-
705. IS. Yammrhi Y.. aad H. YaeMtawn. 1977. Chromosome-
membtane association in Bacillus subtilis- III. Isolation aad characterization of a DNA-protein complex carry-
in| replication onfia markers. J. Mol. Bui. II*
219-253. 19. Yarof, F. E-. P. Haywood, aad M. PMIeck. 1970. IsoUnon
of L-fortns of Bacillus subtilis which *row in lipoid medium, i. Bacterial. 1*1*67-170. 2a Yoon* F. .. and C. A. WPron. 197* Resiston of the linkape map of Bacillus subiibs. p. 616-703. In G. D. Faimaalad.). Handbook ofhsochemistry aad moiecuiar
btoiocy. 3rd ed.. sect. B. rol. 2. CRC Prom. Clevtiaad.
OMo.
CMA- 003274
15
TRANSFORMATION - 1978 Proc. 4th Internat. Mtg- Bacterial Transformation
245
RESTRICTED CHROMOSOME-MEMBRANE ASSOCIATION IN A STABLE L-FORM OF BACILLUS SUBTILIS. S. Horowitz. R.J. Doyle. and U.N. Streips, Department of Microbiology and Immunology, University of Louisville, Schools of Medicine and Dentistry, Health Sciences Center, Louisville, Kentucky, 40232 (USA)
ABSTRACT
A stable L-form (sal-1? of Bacillus subtills BR151 was found to retain a chromosome-membrane association. The attachment of the chromosome to the membrane in the L-form is specific for the replication origin but not for the replication terminus. These results are in contrast to those obtained with the parental, cell-walled strain in which both the origin and terminus of chromosomal replication are preferentially attached to the membrane.
INTRODUCTION
Attachment of the chromosome to the cytoplasmic membrane and to the cell wall has been well demonstrated in cell-walled prokaryotes and is postulated to be instrumental in DNA segregation and division control [1,2,3,4]. This attachment is specific for the origin and terminus of chromosomal replication and for the replication point (1,4,51. In Mycoplasma the chromosome was also found to be attached to the membrane [1,6]. Studies of unstable L-forms, utilizing electron microscopy, have also revealed chromosome-membrane association [7]. Yet, the genetic specificity of the chromo somal attachment in cell wall-deficient prokaryotes has not been studied. In this report, we demonstrate that a stable Lform (sal-1) of B. subtilis BR151, which has no cell wall polymers and divides aberrantly [3,9, R.H. Gilpin personalcommunication], retains a chromosome-membrane association. The attachment is preferential for the region at the origin of chromosomal replication, but the specific attachment of the region close to the replication terminus has been lost.
MATERIALS AND METHODS
Bacterial strains. The stable L-form (sal-1) of ,B. subtilis 8R151 [8,9] was kindly provided by R. W. Gilpin and retains the metBIO marker. The parental strain, J5- subtilis BR151 lys-3, trpC2, metBlO, was transformed to prototrophy for
CMA 003275
246
lya-3 and trpC2 with JJ. subtilia U168 DMA to maintain the save auxotrophic background am the L-form. All strains used as recipients in the transformation experiments are listed elsewhere [10].
Media and growth conditions. The L-form (sal-1) was grown in sal-1 medium [10] which contains 1.2M NaCl for stabilization, according to a modification of the technique described by Gilpin at al [9], la the presence of deoxyadenosine (200 pg/ml) and ^C-thymidine (0.1 pCi/ml, 53 mCl/mmole) for about two generations. The culture was washed in HCP buffer [11] plus 1.2M NaCl and lysed in NCP buffer by osmotic shock. The parental strain, B. subtills BRJL51 metBlO. was grown and labeled under the same conditions as the L-form but without the NaCl, washed in NCP buffer, end lysed by addition of lysozyme (0.5 ng/ml).
Renosrafin sradlents. Lysates of the L-fora and its parental strain were applied onto 0-38X linear Renografln density gradients [11] and were centrifuged, fractionated and counted according to a modification of the technique described by Ivaria and Pane [11].
Transformation procedures. The procedures for the development of competence and transformation were according to those described by Boylan et al[12]. Dilutions of the peak fractions from the Renografln gradients served as donor DNA.
RESULTS /
Attachment of the chromosome to the membrane. Uniformly labeled DNA from an unsheared lysate of the L-form sal-1 (Materials and Methods) forms one distinct band at the lower part of the Renografln gradient. This band corresponds to the membrane-DNA (mDNA) peak which is found in the uncreated lysate of the parental strain B. subtilia BR151 metBlO (results not shown). The DNA attached to the nembrane of both the Lform lysate and the lysate from the parental strain contains about 80Z of the label incorporated. Shearing the L-fora lysate by vortexing for 30 seconds at setting no. 6 causes a decrease In the amount of labeled DNA which appears in the m-DNA peak and generates a slower sedimenting peak which bands at the upper part of the Renografln gradient. This new peak corres ponds to the free DNA (f-DNA) peak of the parental strain (results not shown). The distribution of the uniformly labeled DNA from the L-form sheared lysate consists of about 552 label which appears as free DNA and about 30% which appears as firmly attached membrane associated DNA. This distribution is similar to that of the uniformly labeled DNA from the sheared
CMA 003276
247
lysate of the parental strain [10].
Genetic analysis of the specificity of chromosome attachment. Since the DNA isolated in the Renografin gradients can be used in transformation assays, genetic analysis for the specificity of DMA attached to the membrane was performed, using peak fractions from the sheared lysate of the L-fora and the parental strain as donor DNA. Genetic markers were tested throughout the chromosome and included markers at the origin and terminus regions of chromosomal replication as well as internal loci. The specificity of the attachment was determined by the membrane enrichment index (MEI), calculated according to Sueoka and Quinn [2] using leuA8 as a standard. Savaral transformation experiments were performed for each marker with both the L-form and the parental strain DNA peak samples,and the average MEI was calculated. An MEI value which equals or exceeds 1.40 was taken to indicate chat the marker is enriched in the DNA attached to Che membrane, hence preferentially bound. An MEI value close to 1.00 was accepted to show no specificity for the attachment to the membrane. The results from the transformation experiments are shown in Figure 1. None of the internal markers that we have examined has any specificity for association with the membrane in both the L-form and Che parental strain. The origin region of chromosomal replication (purAlb and cyA14) in the L-form Is preferentially attached to the membrane as is the case in the parental strain. However, the region close to the replication terminus (trpC2. thyB. citK5. gltA292. and thvA) does not appear to be attached to the membrane of the L-form although it is preferentially attached to the membrane in the parental strain.
DISCUSSION
This study demonstrates that the L-form, sal-1, retains a membrane-chromosome association in both sheared and unsheared lysates. This attachment is quantitatively similar to that of the parental strain and may indicate the importance of maintaining such an association for normal cell growth.
Cenetlc analysis for the specificity of the membranechromosome association in the L-form shows that the preferential attachment of the origin of chromosomal replication is retained. However, specificity for the attachment of the terminus region has been lost, when compared to the parental strain. This finding suggests that the two sites of attachment are different, and that the attachment of the origin is of primary Importance. The loss of association, of the terminus to the membrane In the I.-form could be the
CMA 003277
248 A.
. * 5 ** 50 J
50 J*
Figure 1. Cenacle analysis of at-DWA from the L-fom end its perentel strain. Genetic markers along the entire chromosome of both the L-form and its parental strain were examined for specific enrichment In membrane samples (ME1) by transformation (Materials and Methods). Represented Is the genetic map of the L-form sal-1 (A) and of the parental strain BR151 metBIO (B). The genetic map of Bacillus subtilla was constructed from those of Lepesant-Kejzlarova et al [13] and Young and Wilson [14], Each marker Is designated as enriched () or non-enrlched (o) in m-DNA samples. Replication origin (0); Replication terminus (T).
CMA 003278
249
result of one or more of che following physiological and/or genetic alterations. First of all, the loss of the cell wall nay have removed an outer surface site for terminus attachment [15,16]. Secondly, a loss or alteration of a binding protein(s) which aids in Che specific attachment of the chromosome to the membrane (or cell vail) could be reflected In the loss of association of the terminus region. Also,a temperate bacteriophage which inserts in this area of che chromosome [17] could participate in the binding of the genome. The L-form could have lost such a bacteriophage. Finally, the presence of a high concentration of salt (1.2M NaCL) throughout the growth cycle of the L-form could be responsible for the dissociation of specific, bound regions of the chromosome [3,9]. We are presently investigating all of these possibilities.
The chromosome of . subtills has been found to hind to the cell wall polymer [7,15]. It is attractive to speculate that any alteration of the integrity of the cell wmll-proeeinmambrane-DNA complex would result in aberrant division and DMA segregation patterns. Our observation that the L-form, sal-1, of 8. subtills is altered in a part of the replication complex, the~attachment of the terminus of chromosome replication, provides initial support for such a speculation. It also provides opportunity for further studies on the role of the bacterial outer surface in DNA replication and segregation, and cell division.
ACraoWLEDCMETCS
We wish to thank F. E. Toung end R. W. Gilpin for many fruitful discussions. This work was supported by an NSF grant (?CM 78-08903) to R.J.O. end U.N.S., a grant from the Manufacturing Chemists Association to U.N.S., and an Institutional American Cancer Society grant from the University of Louisville to S.H. and U.N.S. (
7
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5 R.J. Hye, M.A. O'Sullivan, K. Howard and N. Sueoka in "Microbiology-1976", edited by D. Schlessinger, p. 83-90, American Society for Microbiology, Washington, D.C., 1976.
6 D.C. Quinlan and J. Manlloff, J. Bacterlol. 1972.112.13751379.
7 A. Ryter and O.E. Landman in "Microbial Protoplasts, Spheroplasts and L-forms", edited by L.B. Guze, p. 110-123, The Williams and Wilkins Company, Baltimore, 1968.
8 F.E. Young, P. Haywood and M. Pollock, J. Bacterlol. 1970, 102.867-870.
9 R.W. Gilpin, F.E. Young and A.N. Chatterjee, J. Bacterlol. 1973.113.486-499.
10 S. Horowitz, R.J. Doyle, F.E. Young and D.N. Streips, submitted for publication.
11 R.D. Ivarle and J.J. Pane, J. Bacterlol. 1970.104.839-850.
12 R.J. Boylan, N.H. Mendelson, D. Brooks and F.E. Young, J. Bacterlol. 1972.110.281-290.
13 J. Lepesant-Kejzlarova, J.A. Lepesant, J. Welle, A. Blllault and R. Dedonder, J. Bacterlol. 1975,121.823-834.
14 F.E. Young and G.A. Wilson in "Nucleic Acids II", edited by C.D. Faaman, p. 686-703, CRC Press, Cleveland, Ohio, 1976.
003280 CMA
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15 W.C. Brown, R.J. Doyle and U.M. Streips, Prep. Biochem. 1976,6,479-482.
16
R.J. Doyle, tf.N. Streips, V.S.C. Fan, W.C. Brown, H. Mobley and J.M. Mansfield, J- Bacteriol. 1977.129,547-549.
17 S.A. Zahler, R.Z. Korman, R. Rosenthal and H.E. Hemphill, J. Bacterlol. 1977,129,556-558.
CMA 003281
INTERFERON: PROPERTIES AND CLINICAL USES A. Khan, N.O. Hill, and G.L. D to, eds. PP- 589--598, Wadley Institutes of Molecular Medicine, Dallas, IX, 1980.
^
INHIBITION OF INTERFERON INDUCTION AS A SCREEN FOR THE CARCINOGENIC POTENTIAL OF CHEM1G\LS*
Gerald Sonnenfeld, Mary Carol Barnes, Julia Schooler and Uldls N. Streips
Department of Microbiology and Immunology University of Louisville School of Medicine
Louisville, Kentucky, USA
ABSTRACT
The induction of murine Interferon by Newcastle disease virus has been shewn to be inhibited by pre-treatment of fibroblasts with Various carcinogens. The present study has extended the range of carcinogens to include chloroacfctaldehyde. Chloroethanbl and chloroacetic acid, rarely carcinogen ic analogs of chloroacetaldehyiffe-, bad no significant effect on interferon induction by Newcastle disease virus. When polyriboinosinic-polyribocytidylie acid was used as an interferon inducer, induction of interferon was also Inhibited by protreatment of the cells with chloroacetaldebyde. Addition of reduced glutathione, which can trap active metabolites of carcinogens, abrogated the effect of a carcinogen on inter feron induction, suggesting that fibroblasts can activate carcinogens in the Inhibition of Interferon induction system. Following further verification of the ability of the inhibit ion of interferon induction system to discriminate among chemicals on the basis of carcinogenic potential, this test could become part of a comprehensive battery of tssts for chemical-carcinogenicity.
*This work was supported by grants from the American Cancer Society No. INI 11C and the Manufacturing Chemists' Associat ion, and the National Aeronautics and Space Administration under Interchange NCA2-OR400-901. M.C.B. was the recipient of s Graduate Student Research Grant from the University of Louisville Graduate School, and J.S. was a Summer Research Scholar of the University of Louisville School of Dentistry.
003282
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INTERFERON: PROPERTIES AND CLINICAL USES
INTRODUCTION
Many different tests have been developed over the past several years to determine the carcinogenic potential of chemicals. Several of the early tests, such as the Ames Salmonella test (1), were able to determine the mutagenic potential of chemicals, but could not consistently discrim inate between mutagens and carcinogens. Several recently de veloped assays, which involve determination of the activat ion of "SOS'* repair in bacteria, have apparently been able to differentiate between carcinogens and mutagens (2,3). How ever, these tests suffer from the drawback that they are carried out in prokaryotic cell, systems which may not he analagous to the systems operative following exposure of a mammalian cell to a chemical.
Maaaalian tests to determine the carcinogenic potential of chemicals have been developed, hut also suffer from sev eral drawbacks. Transformation of cell cultures or induct ion of tumors in animal models require extended periods of time for the carcinogenic potential of e chemical to he ex pressed. In addition, if a chemical is carcinogenic only at a very low rate, massive quantities of animals would he re^ qulred to observe die carcinogenic event (A).
DeMaeyer end DeMaayer-Culgnard have shown in early studies that pre-treatment of rat flbroblaats with several carcinogens Including ben2o-( a) -pyrene end 3-methylcholanthrene resulted in reduced interferon production when the cultures were challenged with vaccinia vlrua (5,6) . Benzo(c)-pyrene, a rarely carcinogenic mutagen and an analog of banco-(u)-pyrone, had no effect,on Interferon induction. Ve have recently extended these studies to a murine system and have shown that ^several other suspected carcinogens, includ ing Aflatoxin-B., 2-aminofluorene, styrene oxide, and methyl methenesulfonatc, all inhibited interferon induction by New castle disease virus (NDV) in mouse embryo fibroblasts (7). Ethyl methancsulfonate, a rarely carcinogenic analog of methyl metlianesulfonate, also had no effect on interferon induction.
The present study represents an extension of the exam ination of the effects of carcinogens on the induction of interferon. Pre-treatment of mouse embryo fibroblasts with the postulated carcinogen chloroacetaldchyde resulted in
CMA 003283
Inhibition of interferon induction when the cultures were challanged with NOV. Treatment of the cultures with cliloro-- acetic acid and chloroetband1, rarely carcinogenic analogs of chloracetaldehyde, did not significantly affect interferon induction. These data suggest that the inhibition of inter feron induction system may be useful as an assay for the car cinogenic potential of chemicals, following more extensive studies and confirmation of results. In addition, cfiloroacetaldehyde treatment inhibited interferon induction by polyriboinosinic-polyribocytidylie add (poly I:C), suggesting' that carcinogen treatment does not disrupt the interaction of virus with the cell membrane resulting in inhibited inter feron production. Finally, application of reduced gluta thione to the cell cultures In conjunction with the carcino gen benzo-(a)-pyrene resulted in abrogation of the effects of the eardaogen on Interferon induction. These data suggest that a system exists in fibroblasts which can activate carcinogens in the interferon inhibition 'system.
MATERIALS AND METHODS
Mouse Embryo Fibroblast Cultures: C57B1/6 derived mice were bred and maintained in our laboratory. Fifteen to eighteen day old embryos were surgically removed from pregnant mice, minced, txypslnlzed In 0.252 trypsin 1-300 (ICN Fharaeentl-- cals, Cleveland, OH) and then suspended in minimum essential medium (Grand Island Biological, Grand Island, NY) supple mented with 102 fetal calf scrum, penicillin and streptomycin and glutamine. Second or third passage2culutres were need in
experiments and were plated in 25cm tissue culture flasks (Falcon Plastics, Oxnard CA).
Chemicals; Chloroacetaldehyde, chloroethanol and chloroacetic acid were generous gifts of Dr. John Wong, Department of Chemistry, University of Louisville. Polyrlboinoslnic and polyrlbocytidylie acids were obtained from P--L Biochemical s, Milwaukee, WI. Benzo-(a)-pyrene was obtained from Aldrich Chemical Company, Milwaukee, HI. Reduced Glutathione was obtained from Calbiochem, La Jolla, CA.
Interferon Induction: Mouse Type I interferon was produced in fibroblasts with the Herts strain of Newcastle disease virus, as described elsewhere (8). After Inactivation of residual inducing virus by pH 2 treatment at A C for four days, the tissue culture supernatants were assayed for anti viral (interferon) activity. Polyrihojnosinic and po.lyribo-
CNIA 003284
592
INTERFERON: PROPERTIES AND CLINICAL USES
cytidylic acid were eomplexnd to poly I:C by heating at A5C
fez one hour. Type I interferon was induced with poly I:C
by adding 50 yg of poly 1:C to tissue cultures for 90 min.,
and* adding additional fresh medium to the mouse embryo
fibroblast cultures.
DEAE-Dextran was included with-'
the poly 1:C to insure maximum of induction of interferon (9).
After twenty-four hours of incubation, the culture supernat
ants were harvested and assayed for antiviral activity.
Interferon Assay: Interferon titers-were determined by plaque reduction on mouse L-929 cells using the Indiana strain of bovine vesicular stomatitis virus (10). The Inter feron titer corresponded to the reciprocal of the highest dilution of test sample that reduced virus plaques by 50Z. One interferon unit in this assay equals 0.88 N1H-C-0Q2-904511 reference units.
RESULTS
Chloroacetaldehyde, chloroethanol, and chloroacetic add were solublized in dimethyl sulfoxide (DMSO) and diluted to appropriate concentrations in tissue culture medium. . The chemicals were then added to different confluent monolayers of mouse embryo fibroblasts. Following twenty-four hours of incubation at 37C, the culture supernatants were removed and
interferon was induced with NDV. The results shown in Table 1 indicate that only treatment with chloroacetaldehyde resulted in decreased Interferon production of 50Z or greater.
TABLE 1
*
EFFECT OF PRETREATMENT OF CELL CULTURES WITH CXILOROACETALDERYDE AND ITS ANALOGS ON INTERFERON INDUCTION BY NDV
Treatment*Interferon TiterX Decrease
NDV Only SMS0 + NDV Chloroacetaldehyde + NDV Chloroacetic acid + NDV Chloroethanol + NDV
300 500
69 225 209
__
-- 77Z 25Z 3QZ
*A11 chemicals were applied at a concentration of 0.005 yM
CMA 003285
SECTION IV: IN VITRO TESTING
593
Since Che interferon assay has an innate two-fold vari ability due to the biological nature of the assay (11), only differences of 5QZ or greater were considered to demonstrate an effect of a carcinogen on interferon induction.
When chloroaeetaldehyde, chloracetic acid and chloroethanol were applied to confluent monolayers and interferon was induced with poly I:C, inhibition of interferon induction of 50Z or greater was again only observed in - chloroaeet aldehyde treated cultures (Table 2). Chloroacetic add and chloroethanol had much less of an effect on the induction of interferon.
TABLE 2
EFFECT OF PRETREAUIENT OF CELL CULTURES WITH CHLOROACETALDEHYDE AND ITS ANALOGS ON INDUCTION OF INTERFERON BY
POLY IsC
Treatment*
Foly I:C only DMSO + poly X:C Chloroaeetaldehyde + poly I:C Chloroacetic acid + poly I:C Chloroethanol + poly X:C
Interferon Titer 430 385 187 268 304
Z Decrease
-- 10Z 57Z 37Z 29Z
*A11 chemicals were applied at a concentration of 0.005 pm.
Benzo-(a) --pyrene was solublized in DMSO and applied to confluent monolayers of mouse embryo fibroblasts at a con centration of 0.5 pm. As has been previously reported for induction of Interferon by NDV (7), this treatment resulted In a significant drop In the titer of interferon induced by poly X:C (Table 3). Addition of reduced glutathione with the benzo-( oO--pyrene resulted in abrogation, at least in part, of the inhibitory effects of benzo-(ej-pyrene on interferon induction by poly I:C (Table 3). Glutathione itself had minimal if any effect on the induction of inter
feron (Table 3).
CMA 003286
694
INTERFERON: PROPERTIES AND CUNIOIL USES
TABLE 3
EFFECT OF CONCOMITANT ADDITION OF GLUTATHIONE AND BENZO-(o) -PYRENE OB INTERFERON INDUCTION BY POLY IiC
Treatment
Poly I:C only Benzo-(a)-pyrene + poly I:C Benxo*-(a) -pyrene + 0.1 pm
glutathione + poly I:C Behso-( cj)-pyrene 4- 0.01 pm
glutathione + poly X:C 0.1 pm glutathione + poly I:C 0.01 pa glutathione + poly I:C
Interferon. Titer 266 76
181
150
347 136 *
X 1increase
* * --
71Z
43Z * *--
26Z
Addition of glutathione to cultures ot nouse embryo fibro blasts did not result in the induction of detectable levels of interferon.
DISCUSSION
The induction of Type 1 interferon has been shown to be inhibited by several carcinogenic chemicals (5-7) . Of par ticular Interest is the observation that when several pairs of highly carcinogenic chemicals and their rarely or non-- carcinogenic analogs, e.g. benxo-(a)-pyrene and benzo-(e)pyrene, ethyl methanesulfonate and methyl' methanesulfonat were tested, only application of the proven carcinogen resulted in the inhibition of interferon induction (5-7). Ve have now extended this observation to include the presumed carcinogen chloroacetaldehyde, and its-rarely carcinogenic analogs chloro acetic acid and chloroethanol. After many additional pairs of carcinogens and analogs are tested in the future, the inhibition of interferon induction by chemicals may prove useful in the screening of chemicals for carcino genic potential.
l
CMA 003287
section iv: in vrrno TcSting
235
Dimethyl sulfoxide has previously been shown to have a r.cn-stetisuicelly significant minimal effect on the in:'.act.ion of interferon by NDV (7). In the present study, no effect of OMSO on interferon induction was observed.
The mechanism of the inhibition of interferon induction was also examined in the present study. Previous work has shown that pre-treatment of rat fibroblasts with carcinogens did not inhibit the plaquing efficiency of vaccinia virus (5). Since poly I:C induction of interferon is also 'inhibited by pre-treatment of fibroblasts with carcinogens, it is not likely that the carcinogen treatment is affecting the binding of viruses to the cell membrane or the budding, of viruses.
Many carcinogens must be activated by microsomal oxidases In order to form final active products before an effect in bacterial or mammalian systems can be observed (12). Benzo-- (a)-pyrene is included among these chemicals. Reduced glutathione can trap these active products and prevent tha occurence of a carcinogenic event (12). Application of reduced glutathione to the inhibition of interferon induction system resulted in at least partial abrogation of the effects of benzo-(a)-pyrene on interferon induction. These data suggest that fibroblasts must contain the type of activation system for carcinogens that renders them potent for the inhibition of Interferon induction.
REFERENCES
1. Ames, B.H., Durstan, W.E., and Yamasaki, E. Carcinogensare mutagens: A simple test system combining liver homogenates for activation and bacteria for assay. Proc. Natl. Acad. Scl.. 70:2281-2285, 1573.
2. Moreau, D., Bslione, A., and Davoret R. Prophage lambda Induction in Escherichia coli K12 envA envB: A highly sensitive test for potential carcinogens. Proc, Natl. Acad. Sci.. 73:3700-3704, 1976.
3. Streips, O.N., Laumbach, A.D., and Yashin, R.E. Bacillus subtilus assays for mutation and DNA repair. In, Bacterial Mutation Monitors for Active Metabolites of Chemical Carcinogens; ed. Felkner, IVC. Marcel Dekkcr, New York, New York. In Press, 1979.
CMA 003288
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INTERFERON: PROPERTIES AND CLINICAL
/*
4. Ames, B.N. Identifying environmental chemicals causing mutations and cancer. Science. 204:587-593. 1979.
5. PeMaeyer-Guignard, J., and PeMaeyer, E. Effect of car
cinogenic and noncarcinogenic hydrocarbons on Interferon
synthesis and virus plaque development. J. Natl. Cancer
Inst.. 34:265-276, 1965.
--
6. DeMaeyer, E., and De-Maeyer-Cuignard, J. * Inhibition by 3-methylchoIanthrene of interferon formation in rat embryo cells infected with Sindbls virus. . J. Natl, Cancer Inst.. 32:1313-1321, 1964.
7. Barnes, M.C., Stxeips, U.N.,' and Sonnenfeld, C. Inhibit ion of interferon induction: Differentiates among chemi cals on the basis of carcinogenic potential. Submitted for publication, 1979.
8. Sonnenfeld, G., Mandel, A.D., and Merlgan, T.C. The immunosuppressive effect of Type H mouse Interferon on antibody production. Cell. Immunol.. 34:193-206. 1977.`
9. Dlanrlni, F., Cahtagalll,
Gagnoni, S., and Rita, G.
Effect of DEAE-dextran on production of interferon by .
synthetic double-stranded ENA In L cell cultures. Pxoc.
Soc. Exp. Biol. Med.. 128:708-711. 1968.
10. Brodeur, B.E., Weinstein, 7., Helmon, K.L., and Merlgan, T.C. Reciprocal changes in interferon production end Immune responses of mouse spleen cells fractionated over columns of lnsolubllzed conjugates of histamine. Cell. Immunol.. 29:363-372.. 1977.11
11. Lockhart, R.Z. Criteria for acceptance of a viral inhibitor as an interferon and a general description of the biological properties of known interferons. In, Interferon and Interferon Inducers; ed., Pinter, N.B. American Elsevier, New fork. Mew York, pp 11-28, 1973.
12. Chasseaud, L.F. Glutathione (reduced) and glutathione
S-tranaferase blocks the carcinogenic event-by trapping
the ultimate metabolites. Adv. Cancer Res.. 29:176-255.
1979.
*
CMA 003289
SECTION IV: IN VITRO TESTING
597
. D^SC'Jij lUil
UNKNOWN: Do you think that this effect is restricted only to these groups of carcinogens and works also with aflatoxins?
SONNENFELD: It does work with aflatoxin. We have shown it with aflatoxin previously as well and there has just been a report published using aflatoxins and the El aflatoidn.
UNKNOWN: And what about tumor promotors?
SONNENFELD: There have been reports using coal dust and also asbestos fibers as well, that `there was reduced induc tion of interferon. The alfatoxln story is very interesting because these investigators at Western Virginia University used four different types of aflatoxin. One type being more potent carcinogen than the other and they found that the de gree of inhibition of induction was related to the potency of the type of aflatoxin that they used.
DEGEE: Do you have any idea whether other cell types could be used for the same tests?
SONNENFELD:- We have used fibroblast. DeMcyer has used fibroblasts. There bas been one study in vitro. I cannot remember the chemical right off hand, but if mice were treated with this chemical they could not produce in vivo serum inter feron. 1 do not know about other things. Of course, we would like to get into studies with Type II interferon as well in lymphoid cells but to this point this type of work has only been done using fibroblast.
GROB: You might have mentioned it but could you please repeat what the pretreatment schedule was before interferon induction.
SONNENFELD: Whet we would do was treat those cells with the carcinogens for twenty-four hours and then wash and maka sure that there was no toxicity of the carcinogen.
UNKNOWN: Jay,, just to support you, the emulsifiers that we used severely reduced the ability of cells to' pro duce interferon. If you use them in very small concentra tions in leukocyte culture, they cause chromosome breaks to a substantial degree higher than the normal controls.
CMA 003290
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INTERFERON: PROPERTIES AND CLINICAL USES
t
SONNENFELD: Which night suggest sons carcinogenic potential of the material.
UNKNOWN: Yes, I couldn't agree more on the need of shifting from a prokaryotic system to an eukaryotic system and X think that your approach is particularly'exciting and promising, especially considering that you can use a human
cell.
SONNENFELD: Yes, we have begun studies along those lines-
CMA 003291
Oncology W: 98-101 (1981)
Effect of Carcinogens and Analogs on Interferon Induction
Mary Carol Barnes, Uldis N. Streips and Gerald Sonnenfeld
Department of Microbiology and Immunology, University of Louisville, School of Medicine, LouisviUe. Ky.
Key Words. Interferon - Carcinogen inhibition
I Abstract. Pretreatment of mouse embryo fibroblasts with several chemicals, including 7,12-dimethylbenz-(a)anthracene, 2-aminoQuorene, aflatoxin Blt benzo-{a )-pyrcne, styrene oxide, and the No. 4 fraction of tobacco smoke condensate, resulted in severely reduced production of interferon when the cells were challenged with Newcastle disease virus. All of the above chemicals are proven or strongly suggested carcinogens. When the analogs methyl methanesulfonate, a potent carcinogen, and ethyl methanesulfonate, a weak carcinogen, were applied to cells, interferon induction was only inhibited by the methyl methanesulfonate. Therefore, carcinogens may directly inhibit the induction of interferon by Newcastle disease virus.
Introduction
Interferon is now being used in several clinical trials for the treatment of various types of tumors, including non-Hodgkin's-type lymphomas [1]. Therefore, it is of interest to determine the type of interactions that exist between interferon and tumor-inducing substances, such as carcinogens.
Early experiments by DeMaeyer and DeMaeyerGuignard [2, 3] suggested that application of known chemical carcinogens, such as benzo-(a)-pyrene, to rat embryo fibroblast cultures prior to challenge with vac cinia virus resulted in inhibition of the induction of interferon by the virus. An additional finding of sig nificance was that benzo-(f)-pyrenc, a weak carcino gen, had no effect on the induction of interferon. These data suggested that carcinogens might have a specific inhibitory effect on the induction of interferon.
The results of the present study confirm and extend these observations. Several known and suspected po tent carcinogens, including methyl methanesulfonate (MMS), markedly inhibited the induction of interferon by Newcastle disease virus (NOV) in mouse embryo fibroblasts. The rarely or weakly carcinogenic analog of MMS, ethyl methanesulfonate (EMS) [4, 5] had little
or no effect on the induction of interferon by .NOV. Therefore, the new data suggest that interferon induc tion is inhibited by pietreatment of cell cultures with an extended group of potent carcinogens.
Materials and Methods
Mouse Embryo Fibrobtast Cultures. 36 H-2k Iyt2.1 mice, a gift of Thomas Huff and Samuel Weilhausen, Department of Microbiology and Immunology, University of Louisville. Ky., were bred and main* tained in our laboratory. IS- to 18-day-old embryos were surgically removed from mothers, minced; iryptiniaed in 0,25% trypsin 1*300 (Pharmaceuticals, Cleveland. Ohio) and then suspended in Gibco minimal essential medium (MEM) with 10% fetal calf serum. Second or third passage cultures were used in all experiments and were plated in Falcon 25 cm1 tissue culture flasks, and were used immediately upon reaching conflucncy.
Chemicals. Aflatoxin B,. 2-aminofluoretie, benxo-(a )-pyrene, EMS and MMS were obtained from Aldrich Chemical Co., Milwaukee. Wise 7,12-Dimethylbeni-(u (-anthracene and No. 4 fraction of to bacco smoke condensate were received from the Kentucky Tobacco Health and Research Institute. Lexington, Ky. Dimethylsulfoxide (DMSO) was obtained from J.T. Baker Chemical Co., I'htllipsburg. NJ. Styrene oxide was kindly pruuded by Dr. John Wong. Depart, ment of Chemistry. University of Louisville, Ky.
Interferon Production. Mouse type 1 interferon was produced in fibroblasts with the Herts strain of NDV, as described elsewhere (61.
CMA. 003292
Carcinogens and Interferon
99
After iMotivation of residual inducing virus by pH 2 treatment at 4 *C for 4 days, tbe tissue culture supernatant Quid was assayed for interferon activity.
butrferon Assay. Interferon titers were determined by plaque reduction on mouse L-929 cells using Indiana strain bovine vesicular stomatitis virus. The interferon titer corresponded to the reciprocal of the highest dilution of test sample that reduced vims plaques by 50%. One interferon unit equals 0.88 NIH HG-002-904-311 reference units (<S|.
Results
Table L Effect of carcinogens on interferon production
Treatment of fibroblasts
Antiviral titer
% decrease from control
Newcastle disease virus 7.12-Dimethyibenz-(a )anthracene + NDV
39.OpM 3.9 nM
2-Aminofluorene + NDV 0.050/iM 0.005 mAT
1,000
100 86
21 247
90 91
98 81
Viability of Mouse Embryo Fibroblast Cultures Mouse embryo fibroblasts were allowed to grow into a confluent monolayer. After reaching confluency, dif ferent cultures were treated for 24 h with several con centrations of the chemicals used in this study. These chemicals included 7,12-dimethylbenz-(a)-anthracene, 2-aminofluorene, aflatoxin Bt, No. 4 fraction of tobac co smoke condensate, benzo-(a)-pyrene, MMS, EMS, OMSO and ethanol. Immediately after removal of the chemicals, the fibroblast cultures were stained with 2 x neutral red, a vital stain. All of the cultures that were treated with the dosages of chemicals that were used in the study were >95% viable by staining criteria. Addi tional cultures that had chemical-containing medium replaced with fresh MEM remained viable for at least another 24 h.
Effect of Known Carcinogens on Interferon Induction The known carcinogens 2-aminofluorenc and 7,12dimethylbenz-(a)-anthracene were diluted in MEM and added to confluent fibroblast cultures. After 24 h of incubation, the culture supernatants were removed. The cultures were then challenged with NDV for 24 h and the supernatants were harvested, pH 2 treated, and then assayed for interferon activity. Reductions in inter feron titers 90% were obtained when compared to non carcinogen treated controls (table I). Several different dosages of chemicals were initially used to determine the dosage for optimum effect without affecting via bility of the cultures, and the data in table I represent the optimal dosages.
Effects of Several Chemicals on Interferon Induction Mouse embryo fibroblasts were treated with several different dosages of various chemicals before attempted induction of interferon with NDV. Aflatoxin Bt, No. 4 fraction of tobacco smoke condensate, benzo-(a)-pyrene, and styrene oxide treatments all inhibited the induction of interferon by 90% or greater (table II).
Table IL Blind study at the effect of various chemicals on inter feron induction
Chemical treatment*
Interferon titer SE
% decrease PNDV* horn control
None (NDV control) Aflatoxin B, 0.05 pM No. 4 fraction, tobacco smoke4 condensate, lOx Benzo-a-pyrene. 0.05 pM Styrene oxide, 0.05 /tM
1.456 455 105 82 8920
122 74 149 60
* 93 95
92 90
<0.05 <0.05
<0.05 <0.05
1 Mouse embryo fibroblasts were preticated with the appropriate chemical for 24 h. Supernatants were removed, calls washed and NOV applied for 24 h. Cell supernatants were then harvested and assayed for antiviral activity. 1 Statistical analysis was performed by means of a Student's T analysis. 1 Arbitrary dilutions of the No. 4 fraction of tobacco smoke con densate were used.
Table 111, Blind study of the effect of a weak and a potent car cinogen on interferon production
Chemical treatment1
Interferon titerSE
None (NDV control) Ethyl mcthaneaulfonate
0.05 ttM Methyl methaiMMiifoitace
0.05 nM
1,436 455 1,680294
137 82
% decrease1 P from control
__
-- >0,5
91 <0.05
1 Experimental protocol as in table It. * EMS and MMS were dissolved in ethanol only.
Tabic II represents the effects of optimum dosages of the chemicals used. DMSO was used as a solvent for all of the above chemicals. Pretreatment of fibroblast cultures with DMSO resulted in a small (0-40%), not
CMA 003293
i L'J BarnevSlfcipi '.nmciiteij
statistically significant decrease in the titers of inter feron induced by NDV.
E.viS and MMS were solubilized in ethanol. Prer-mment of mouse fibroblasts with ethanol had no effect on the tiicrs of interferon induced by NDV. pretreatment of the cell cultures with EMS had a minimal effect on the induction of interferon by NDV, while MMS pretreatment severely decreased the titer of inter feron induced by NDV (table 111).
Discussion
The results of the present study indicate that several well-known carcinogens, including 7,12-dimethyibenz(a)-anthracene, benzo-(a)-pyrene. 2-aminotluorene, aflatoxin B,, and the No. 4 fraction of tobacco smoke condensate, all inhibited the induction of interferon by NDV. Styrene oxide, an important industrial chemical, which was positive in the Ames assay, but negative in all Bacillus assays done to date, also inhibited the in duction of interferon by NDV. Further studies of the carcinogenic potential of styrene oxide may be required.
DMSO has been used in clinical trials as a drug for the treatment of arthritis. However, these trials have been suspended due to the teratogenic potential of the chemical (7, 8]. It is of interest to note that pietreatmem of cells with DMSO did not result in the signifi cant inhibition of interferon induction by NDV.
EMS and MMS are closely related analogs which differ with respect to carcinogenic potential as deter mined by tumor induction [4, 5]. MMS is a highly car cinogenic mutagen, while EMS is a rare or weakly car cinogenic mutagen. In the present study, MMS strongly inhibited the induction of interferon by NDV, while EMS had no significant effect. In a recent study, fibro blasts were pretreated with four different forms of aflatoxin [9J. The degree of inhibition of interferon in duction correlated with the proven carcinogenic poten tial of the aflatoxin forms, ue. the more carcinogenic the form of aflatoxin, the greater the inhibition of inter feron induction. In view of these findings and the pre viously reported discrimination between benzo-(a)pyrene and benzo-(f)-pyrene [3] and the presently observed discrimination between EMS and MMS, car cinogens may directly inhibit the induction of inter feron.
The mechanism by which carcinogens inhibit the in duction of interferon is not known. A toxic effect of the carcinogens to the ceil cultures does not seem likely.
since the results of this study indicate that the target ceils ire aiive when they fail to produce interferon. However, a general effect of the carcinogens on DNA. RNA, or protein synthesis and differential dosage ef fects of potent and weak carcinogens cannot be ruled out and are the subject of future studies.
Other possible mechanisms include alteration of the cell membrane by the carcinogen resulting in reduced interaction of virus with the cells. Recent studies show ing that pretreatment of cells with carcinogens inhibited the induction of interferon by poly-inosinic-poly-cytidylic acid, a nonviral inducer of interferon [10]. In view of those studies and the earlier finding that carcinogen pretreatment does not inhibit the replication of the viruses used to induce interferon [2], it is uniikeiy that virus-membrane interactions are severely disrupted by carcinogen treatment of cells.
Another possible mechanism could involve induction of a protease by the carcinogen in a manner analogous to bacterial 'SOS' repair systems [11]. This protease could degrade induced interferon, or interfere with the control mechanisms for interferon induction. The true nature of the proposed effect of carcinogens on inter feron induction is the subject of extended studies.
The implications of these studies toward an under standing of the mechanisms of carcinogenesis are still obscure. It is possible to speculate that there may be a balance between interferon levels and oncogenesis and that balance may be upset by the action of a carcino gen. In addition, if further studies continue to indicate a differential effect on interferon induction by strong and weak carcinogens, the effect of a chemical on inter feron induction may have some use in determination of the carcinogenic potential of that chemical.
Acknowledgements
W thank Or. R.E. Yashin of the Pmmytvania State University for providing unpublished data and helpful suggestions. This work was supported by grants from the Manufacturing Chemists' Associa tion, the American Cancer Society No. IN-111C. and the National Aeronautics and Space Administration under Interchange NCA2OR400-VU1. M.C. B. wes the recipient o( a Graduate Student Re search Cram from the Graduate School of (he University oY Louis ville.
References
1 Mengan. T.C.; Sikora. K.; Breeden. J.H.; Levy. R-. and Rosenberg. $. A.: Preliminary observations on the effect of human leuko-
OO^ 29*
Carcinogens and Interferon
101
cytc interferon in non-Hodgkin's lymphoma. New Engl. J. Med. 299: 1449-1433 (1979). I DeMaeyer, E. and DeMaeyer-Guignard, J.: Inhibition by 3-methylcholanthrene of interferon formation in rat embryo cells infected wnh Smdbis virus. J. natn. Cancer Inst. 32.- 1317-1321 (1464). 3 DeMaeyer-Guignard, J. and DeMaeyer. E,; Eltevt of carcinogenic and noncarcinogenic hydrocarbon on interferon synthesis and virus plaque development. J. natn. Cancer Inst. 34: 265-276
(1965). 4 Roc, F.L.C.; Mitchley. B.C.V.. and Walters. M.: Tests for car
cinogenesis using newborn mice: 1,2-benzanthracene. 2-naphthylamme, 2-naphihythydroaylamine. and ethyl methanesuifonate. Br. J. Cancer/7: 235-260(1963). 5 Casto. B.C.: Janosko, N.. and DiPaolo. J.A.: Development of a focus assay for transformation of hamster cells in vitro by chemical carcinogens. Cancer Res. 37: 3508--3515 (1977). 6 Sonnenfeld, G.; Mandci. A.D., and Merigan. T.C.: The immuno suppressive effect of type 11 mouse interferon on antibody pro
duction. Cell. Immunol- 34: 193-206 (1977). 7 Caujolle, F. M. E.:Caujolle. D. H.;Cros,S. B..andCalvet, M.-M.J.:
Limits of toxic and teratogenic tolerance of dimethylsulfoxide. Ann. N. Y. Acad. Sci, I4f: 110--126(1967),
. 8 Rubin. L. F.; Toxicity of dimethylsulfoxide, alone and in combina tion. Ann. N.Y. Acad. Sci. 243: 98-103 (1975).
9 l-lahon. N.; Booth. J. A., and Stewart. J.D.: Aflatoxin inhibition ot viral interferon induction. Antimicrob. Agents Chemother. 16: 277 (1979).
Id .vninunfcld. G., Barnes. M.C., Schooler, J., and Streips, U.N.: Inhibition of interferon induction as a screen for the carcinogenic potential of chemicals: in Khan, Hill. Dorn, Interferon: properties and clinical uses. pp. 589-598 (Wadlcy Inst. Molec. Med., Dallas 1980).
11 Within, E. M.: Ultraviolet mutagenesis and inducible DNA repair in Eschtnchia colt, Bact. Rev. 40: 869-907 (1976).
Dr. Gerald Sonnenfeld. Department of Microbiology and Immunology. University of Louisville School of Medicine. Health Sciences Center. Louisville. KY 40292 (USA)
003295
CMA
IMMUNOPATHOLOGIC OBSERVATIONS IN LIVER ANGIOSARCOMA
Enrique Espinosa, M.D.
Department of Pathology University of Louisville School of Medicine
Louisville, Kentucky
I. INTRODUCTION
In hepatic fibrosis and angiosarcoma associated with vinyl chloride exposure of industrial workers, manifestations of the disease could not be detected in most cases until the process was far advanced (1). Normal values of liver function tests were reported in a case with significant vinyl chloride hepa tic fibrosis (2), and only a small percentage of workers of a plant unit where seven cases of liver angiosarcoma were diag nosed had abnormal blood screening tests (3). Thus, conven tional liver function tests do not appear to be sensitive in dicators of vinyl chloride liver disease. Development of more sensitive methods for detecting the disease in early stages would be of great importance. An approach to this may be pro vided by immunologic studies. In such a study the question arises whether the fibrotic and angiosarcomatous livers contain antigens that are different from those present in normal tis sue and whether such changes could stimulate an inmunologic response. The purpose of this study was to search for anti genic changes in the angiosarcomatous tissue and to test for possible presence of an antibody response in the host.
II. PROCEDURES AND MATERIALS USED
A. Patients' Sera and Tissue Specimens
Serum samples from B.F. Goodrich Co. workers with histor ies of vinyl chloride exposure of several years included sam ples from two individuals with liver angiosarcoma, ten with liver dysfunction with fibrosis and ten with normal liver function tests. The patients with angiosarcoma died and the diagnosis was confirmed at autopsy and portions of tumor and neighboring liver tissues were obtained at autopsy. Patients with liver dysfunction with fibrosis included individuals with
927
CMA 003296
abnormalities in liver function tests and fibrosis detected at biopsy. Tissues were also obtained from coroner's autopsies of healthy individuals a few hours after death by gunshot wounds.
B. Tissue Extracts and Antisera
Liver angiosarcoma and adjacent liver tissue and post-mor tem tissues considered to be normal were frozen and stored at -70*C until used. Portions were cut, thawed and homogenized in 2-3 volumes of distilled water in a Potter-Elvehjem grinder in an ice bath until a smooth suspension was obtained. After centrifugation at 20,000 x G for 30 min, the supernatant fluid containing the aqueous extract was lyophilized. Albino rab bits were immunized with the tumor or normal liver extracts in Freund's complete adjuvant and sera collected and stored fol lowing procedures detailed elsewhere (4). Reaction of these immune sera with human serum or plasma was eliminated by ab sorption with 100 mg of lyophilized, pooled normal human serum /ml antiserum. Antisera were routinely absorbed in this man ner prior to use. Additional absorption with tissue extracts was carried out with 100 mg lyophilized extract/ml antiserum. Absorptions followed a procedure described previously (5).
C. Treatment of Tissue Extracts
Enzymatic treatment of tissue extracts was carried out with Pronase and trypsin as previously described (6). Periodate oxidation was done according to Rajam et al. (7). Ammonium sulfate and cold ethanol fractionations were carried out as
detailed (8).
D. Immunodiffusion and Immunofluorescence
Double immunodiffusion was carried out in 0.84 agarose in phosphate-buffered saline pH 7.2 (PBS) containing 0.11 sodium azide. Circular wells, 2 am in diameter, 3 mm apart were used. Immunoelectrophoresis was performed according to Schei-
. .degger (9) using 0.8% agarose in 0.025 M veronal buffer at pH
82 In immunofluorescent studies cryostat sections of rat kid
ney, stomach or intestine and liver (4 microns) were used as substrate for antimitochondrial, antismooth muscle and anti nuclear antibodies. Liver sections from rats exposed 4, 8 and 14 days to 1-2% vinyl chloride for 4 hr/day were also used. The sections were covered with dilutions of patients' sera for 45 min at room temperature, washed twice in PBS for 10 min and then covered with fluorescein conjugated IgG fraction of rab bit anti-human immunoglobulins serum (Cappel Laboratories, Inc.) for 45 min and washed as before prior to examination. Cryostat sections of liver angiosarcoma'and liver tissue con-? sidered to be normal (4 microns) were washed twice in PBS for 10 min to wash off nonfixed immunoglobulins. After drying,
928
CMA 003297
serum (Cappel Laboratories, Inc.). Sections were washed as above and examined under the fluorescent microscope. Represen tative frozen sections were stained with hematoxylin and ecsin to allow correlation between immunofluorescence and the histo logical findings. The antigenic preservation of the tissues was indicated by the demonstration of their staining by anti nuclear factor according to the indirect iatmunofluorescent procedure.
E. Elution of Tumor-bound IgG
The tumor and liver tissues were extracted five times with PBS to wash off nonfixed immunoglobulins and then extracted at pH 2.5 to release oound IgG according to a procedure applied in the elution of renal-bound antibody (10).
7. Circulating Tissue Antigens
Liver-specific antigen LSA (8), tissue antigens of wide organ distribution (4) and bile antigens (11) were tested in the patients' sera by immunodiffusion as described previously.
III. RESULTS
A. Angiosarcoma-related Antigen
To test for presence of new antigens appearing in liver angiosarcoma, antiangiosarcoma serum was absorbed with human serum and liver extract and tested by immunodiffusion with ex tracts of both normal liver and angiosarcoma tumor at varying concentrations. This absorption eliminated all reactivity with liver extracts prepared from five normal individuals but not with the angiosarcoma extracts where one line of precipi tation remained (Fig. 1). This line of precipitation could still be seen after additional absorption of the antiserum with kidney extract. In contrast, absorption with the tumor extracts eliminated completely the angiosarcoma-related line of precipitation. Absorption with spleen and lung extracts also eliminated this line of precipitation. Thus, the antigen appeared to be of restricted tissue distribution and not an giosarcoma specific. The antigen was inactivated by trypsin and Pronase and thus appeared to be a protein or closely asso ciated to protein. Incubation of the tumor extracts for 1 hr at 4*C in citrate buffer, pH 2.5, resulted in inactivation of the antigen whereas incubation in phosphate buffer, pH 5.0, neutral or alkaline pH up to pH 10.0, did not affect it. The antigen was shown to be relatively thermolabile. Incubation of the tumor extracts for 30 min in PBS at 25* and 56*C did not affect the antigen whereas incubation at 70*C and higher
929
CMA 003298
completely inactivated^it. She .antigen 'prgcltyitated mainly at 20-30% saturated ammonium Sulraie'nandjCiLt^%tft38ol concentra tions of 30-70% (Table I).
B. Absence of a Normal Tissue Antigen in Angiosarcoma
Antiliver serum absorbed with human serum gave several arcs of precipitation in imnunoelectrophoresis with extracts of normal liver and angiosarcoma tissue (Fig. 2a). These lines could not be seen following additional absorption of the anti serum with normal liver. In contrast, absorption with liver angiosarcoma extract failed to eliminate one of the arcs of precipitation (Fig. 2b). Thus, the tissue antigen related to this arc of precipitation appeared to be absent in the angio sarcoma tous tissue whereas the antigens corresponding to the other arcs were present. The absent antigen in angiosarcoma was shown to be present in kidney and lung extracts in addi tion to liver by absorption and direct imnunodiffusion tests. Physicochemical characterization studies indicated this anti gen to be unaffected by Pronase and trypsin and inactivated by periodate treatment. The antigen was relatively thermostable withstanding incubation at 70*C for 30 min in PBS. The anti gen was destroyed following incubation of the liver extract in citrate buffer at pH 2.5 or lower for 1 hr at 4*C; incubation at pH 5.0 or higher (up to pH 10.0) did not affect it. This antigen precipitated over a wide range of ammonium sulfate and ethanol concentrations (Table I).
C. Angiosarcoma-bound IgG
IgG fluorescent staining appeared in a linear pattern in the peripheral portion of the tumor cells suggesting in vivo binding by the tumor of the immunoglobulin. This staining is illustrated in Fig. 3. Fig. 4 shows the angiosarcomatous cells surrounding irregular vascular spaces. Relatively coarse, linear fluorescence was also present along some hepa tic cords and strands of connective tissue. There was no ev idence of IgM. Control post-mortem liver tissue did not show any significant fluorescence of bound IgG. Staining for IgG of the tumor sections did not change after several washings at pH 7.2 indicating that the IgG was firmly bound to the tumor. In contrast, sections showed marked diminution of staining after washing at pH 2.5. Elution of bound IgG from salineextracted tumor homogenates was thus attempted at aqid pH. With the five successive saline extractions the amount of sa line soluble IgG gradually diminished to nondetectable levels; and at acid pH bound IgG was released from the homogenate. Similar treatment of liver homogenates did not demonstrate presence of bound IgG (Table II).
0. Circulating Autoantibodies and Tissue Antigens
Serum autoantibodies to nuclei, mitochondria and smooth muscle were negative in all patients examined. In addition,
930
CMA 003299
serum from these patients did not show reactivity with liver from rats exposed to vinyl chloride. Liver-specific antigen LSA (3), bile antipans (11) and other tissue antigens (4) as sociated with liver damage were not detected in these pa tients.
IV. DISCUSSION
The immunologic characteristics of cancer have been under intense investigation during recent years, and antigenic dif ferences between normal and malignant tissue are considered to be fundamental factors in the immunologic approach to cancer therapy and diagnosis. Liver angiosarcomatous tissue was thus analyzed in this work for presence of neoantigens, normal tis sue antigens and tumor-bound immunoglobulins. Several normal tissue antigens were found by immunodiffusion to be present in the tumor, but one antigen of rather wide organ distribution was not detected. These findings are in agreement with obser vations in other tumors indicating that tumor cells contain many of the antigens of their original hosts and lack some normal tissue antigens. Tor example, immunohistochemical studies have shown the loss of kidney antigens in stilbestroland x-ray-induced kidney tumors (12), of skin antigen in 3methylcholanthrene-induced mouse squamous cell carcinoma (13) and of certain muscle antigens in 20-methylcholanthrene-indueed rat rabdomyosarcoma (14). By far the most extensively studied class of tumors are the chemically induced hepatomata where deletion of liver antigens have been shown in tumors in duced with 4-dimethylaminoazobenzene (IS, 16), diethylnitrosamine (15) and 2-acetomidofluorene in the rat (IS, 17) and o^ aminoazotoluene in the mouse (18). In human carcinoma, loss of, antigens have been reported in squamous cell carcinoma (12, 19), loss of t)ie ABH blood group isoantigens in some ' solid tumors (207 21) and of HL-A isoantigen in lymphoma (22). In addition, it has been well documented that as cells trans form from a normal state to malignancy they may gain new anti genic specificities. Tumor-specific transplantation antigens have beeq/.demonstrated in a number of experimentally induced tumors (23-26) as well as in spontaneous tumors in man (27-' t 29). In the present report immunodiffusion analyses of liver angiosarcoma and other human tissues with rabbit antiangiosar coma serum did not indicate the presence of a tumor-specific antigen but rather of an antigen found in lung and spleen but not in liver and kidney. This antigen is being further char acterized in our laboratory.
Of particular interest is the demonstration of tumor-bound igG by immunofluorescence and elution experiments. This find ing must however be interpreted with caution and should be confirmed in biopsy specimens. The tumor-bound IgG may repre sent specific antitumor antibody, antibody fixed by the tumor tissue "nonspecifieally* or part of both. Further speculation is premature until it has been shown that the staining pattern
931
CMA. 33oo
is due to the deposition of a specific antibody, that the elu ted antibody is specific or until the relevant antigen has been identified. Work is in progress to determine the precise significance of the finding of IgO in the tumor.
V. SUMMARY
Immunodiffusion analyses of human liver angiosarcoma asso ciated with vinyl chloride exposure indicated presence in the tumor of an antigen not detected in normal liver and kidney but found to be present in lung and spleen. This antigen was shown to be a protein, inactivated by Pronase and trypsin, relatively susceptible to heating and to acid pH and precipi tated mainly at 20-30% saturated ammonium sulfate and at 3070% ethanol concentrations. The tumor was shown to contain several antigenic constituents of normal tissue but one normal tissue antigen was not detected. This antigen was character ized as a substance unaffected by Pronase and trypsin and in activated by periodate. It was relatively thermostable, af fected by acid pH and precipitated over a wide range of anmonium sulfate and ethanol concentrations. Tumor specimens ob tained at autopsy contained bound IgG as shown by immunofluor escence and elution experiments suggesting possible in vivo binding of IgG to the tumor.
Acknowledgements; The author wishes to thank Drs. W. M. Christopherson, G. R. Schrodt and P. H. carstens for fruitful discussion and advice about the histologic sections and Drs. C. Tamburro and L. Maak for providing serum samples and au topsy material. I also wish to thank Miss M. VanBraun and Mrs. V. Petrey for skilled technical assistance. This work was supported in part by a grant from B. F. Goodrich, Co.
932
CMA 003301
TABLE I. Angiosarcoma-related Antigen and Antigen Absent from the Tumor in Ammonium Sulfate and Ethanol Fractions
a Presence of
Fraction tested
Angiosarcoma-related b
antigen
Antigen absent from
c Angiosarcoma
Ammonium sulfate:
0-20% saturation
+
-
20-30% saturation
*
30-50% saturation
-
+-M-
50-70% saturation
Ethanol:
0-20%
-
H-
20-30%
-
+++
30-50%
++
+++
50-70%
d SN
a
M-+,
+ indicate strength of double diffusion reaction
in dilution assay,
b Detected in angiosarcoma fractions.
c
Detected in liver fractions,
d SN * supernate of the 70% ethanol precipitation, dialyzed
and lyophilized.
CMA 003302
933
t
TABLE II. IgG in Saline and Acid Extracts of Angiosarcoma and Liver Tissues
weight solid extracted from a
Preparation tested 1 gm (wet weight) tissue Presence of IgG
(mg)
Angiosarcoma:
Saline extract 1 Saline extract 2
29.8 8.6
+++ -H-
Saline extract 3
6.2
+
Saline extract 4 Saline extract 5 Acid extract
5.6 6.1 6.1
++
Liver: Saline extract 1
47.4
+++
saline extract 2 Saline extract 3
14.5 8.6
+
Saline extract 4
7.4
-
Saline extract 5 Acid extract
6.4 9.0
-
a Tested by immunodiffusion at concentrations of the eluates
ranging up to 2%. Present at concentrations 0.05-0.1% (+++);
0.2-0.5% (++); 1-2% {+); negative at 2% (-).
934
, CMA 003303
FIG. 1. Demonstration of anilosarcoca.-rels.ted antigen. Peripheral wells have 2-fold serial dilutions of liver angiosarcoma extract (a) and normal liver extract (b). Dilutions are clockwise and start at 100 mg/ml in the upper right well. Central wells in each plate contain rabbit antiangiosarcoma serum absorbed with normal human serum and liver extract.
FIG. 2. Demonstration of tissue antigen absent in angiosarcoma, (a) TTough contains rabbit antihuman liver serum absorbed with normal hwan senmi. (b) Trough contains the antiliver serum additionally absorbed with angiosarcoma extract. In both plates top wells have 10% solution of liver extract and lower wells angiosarcoma extract. Anode is to the right.
93S
00^ ok
FIG. 3. iMunofluoroscant staining of liver angiosarcona by fluorescein conjugated IgG fraction of rabbit antihunan IgG seruu (x 400).
936
CMA 003305
aim. exp. Jmmaml. (1976) 25,410-M7.
19
Circulating tissue antigens
III. IDENTIFICATION AND CHARACTERIZATION OF ANTIGENS OF LIMITED AND OF WIDE
BODY DISTRIBUTION IN HUMAN GALLBLADDER BILE. PRESENCE IN SERUM OF PATIENTS WITH ACUTE HEPATITIS*
F.. ESPINOSA Department f Patkolagy, Univenity of f^nitrille Sekael ofMedina*, Ltmtriile, Kentaeky, ILS..L
[Reetned 19 Jtnavy 1976)
SUMMARY
Three antigens shared by bile and tissues (BT-l, BT-2 and BT-3) and one shared by bile and saliva (BA) were identified in human gallbladder bile by immunodiffusion. The former were detected in all bile specimens examined, whereas the latter was detected only in half. BT-l was limited in distribution to kidney, urine and bile; whereas BT-2 and BT-3 were widely distributed, mainly in liver, kidney, lung and bile. The antigens were not present in biles of other mammals tested, with the exception of BA which was also present in Rhesus monkey. All antigens were inactivated by Pronase, had relative electrophoretic mobilities of serum globulins and separated from each other in Scphadex G-200 gel filtration and ammonium sulphate fractionation. Ethanol inactivated BT-l and precipitated the other antigens. BT-2 and BA were relatively resistant to boiling temperature and acid pH, whereas BT-l and BT-3 were susceptible. Antigens BT-2 and BT-3 were detected in serum of patients with acute hepatitis but not of patients with other diseases or of normal controls.
INTRODUCTION
In earlier work both normal scrum proteins and proteins apparently specific to the biliary tract have been identified in bile (Rawson, 1962; Hardwickc et al., 1964; Clausen, Kruse Sc Dam, 1965; Yoon, Shim & Kil, 1966; Wales et al., 1969; Englert, Wales Sc Straight, 1970). Yoon et al. (1966) and Englert et al. (1970) demonstrated by immunoelectrophoresis that rabbit antihuman bile serum ab sorbed with normal human serum was reactive with as many as three or four antigenic components of human bile. These antigens were considered to be bile-specific although a relationship to other body fluids and tissues was not investigated. We became interested in this relationship after finding that two of the tissue antigens detected in scrum of patients with hepatitis (Espinosa, 1974) related to antigens in bile, as demonstrated in the present work. The primary objective of this investigation was the identifi cation and characterization of both bile-specific antigens and antigens shared by bile and tissues.
MATERIALS AND METHODS
Bodyfinidt, torn* extent* mod patienti' itre. Human gallbladder bile and tiuem considered to be normal at post-mortem examination men obtained from coroner'a autopsies of eight adult subject* within a Tew hour* after death. Animal bile wax .
obtained immediate!]' after killing, liile was centrifuged at 12.000 g for 10 min at 4"C The supemate wax lynphilizcd and
kept in a desiccator until tested. Tissue saline extracts were prepared as previously described (Espinosa 6c Kaplan, 1970).
* Presented in part it the 59th Annual Meeting of (he f ederation of American Societies for Experimental biology, Atlantic City, New Jersey, April 1975.
Correspondence: Dr Enrique Espinosa, Department of Pathology, University of Louisville School of Medicine, I Icalth Sciences Center, Louisville, Kentucky 40201, U.S.A.
410
CMA 003306
Antigens in bile
411
Uria* to(i zliv* specimens were provided by five normal ulults. Urine wax dialysed Igimsr distilled water and tyopbilued. Saliva was lyophilized. Serum samples were obtained from patterns at Louisville's General and Sc Anthony Hospitals within the first week of hospitalization. Of the thirty-three patients tested, eighteen had acute hepaous (five virtu A, seven virus B, five alcoholic and one carbon tetrachloride intonation), four liver cirrhosis, two obstructive jaundice, two liver angiosarcoma, five pneumonia and two pancreatitis. Scrum samples (rani forty-eight normal blood donors were obtained from the local Red Cross blood centre. Samples were tested by double immunodiffusion as soon as obtained and kept frozen at - 35'C when further testing wss contemplated.
Preparation of onttttra. Lyophilized bile and saline extracts of liver, kidney and cardiac and skeletal muscle were each dissolved in saline in a concentration of 20 mg/ml and emulsified in an equal volume of Freund's complete adjuvant. Albino rabbits were given weekly injections as follows: first injection, 0-4 mi ofidjuvuu mixture in the four footpads intndermally; second and third injection, 1 ml intramuscularly, divided between two sites; fourth injection. 1 ml of the extract solution (20 mg/ml) without adjuvant given intrapentonally. Serum was prepared from Mood withdrawn just prior to immuniza tion and 10-1$ days after the last injection; serum was stored frozen until used. Reaction ofthese amisera with normal human serum and plasms was eliminated by absorption with 100 mg lyophiliied, pooled normal human serum/ml of antiserum. Absorptions were as previously described (Espinoes Sc Kaplan, 1968% Such absorbed andeera were used reutindy in this work except as otherwise indicated. Both absorbed and unabsorbed pretmmuaizadon sen gave no reaction with either body fluids, tissue extracts or patients' am in immunodiffusion tests.
DanMt immutadiffiaioo and immmaUttnphorttu. Double immunodiffusion was performed in 0*8% agarose in PBS, pH 7-2, containing 0-1% sodium azide. Circular wells 2 mm in diameter, 3 mm apen, were used. Immunoelectrophoresis was performed according to Scheideggcr (1955) using 0-8% agarose in 0-025 m Veronal buffer it pH 8-2. The electrophoresis wss carried out with ice-cooling at 5 mA/slide for 120 min. Both the doubt* immunodiffusion and hmnunoclecttophoresia plates were incubated for 48-72 hr. Plates were then washed in the cold with daily changes of saline for 4-5 days and then photographed.
Fratitaaanoa ofUlr. Scphadcx G-200 get filtration of 1 ml of a 10% solution oflyophtlised bile in PBS wax preformed it 4*C in an 85 x 1-5 cm column. PBS containing 0-02% sodium aside was used as eluant at a flow tare of 5-6 ml/hr; fractions of2 ml were collected. In some caaa, antigen-containing fractions were concentrated by lyophflianion.
Ammonium sulphate and coldctbtnolfrxctxxvitvons wereearnedout according to procedures detailed previously (Espinosa, 1973).
Treatment oftile, Treatment of the bile solution (100 mg/ml PBS) with Pranaae was carried out with the enzyme, $ ittg/ml PBS, it 37*C for 24 hr. Controls included simples without enzyme, with snayme hut without incuhetion end with enzyme alone.
The effect of pH was tested by incubating solutions of tyophiiizod bk in ritims buflfer at pH 2-5 snd 3-5 and phosphate buffers at pH 5-0,7-0,94) and 10-0 for 1 hr at 4C Precipitation occurred at pH 2-5. For antigen testing, pH was adjusted to neutrality which brought precipitated material into solution.
RESULTS
Immunodiffusion analyses ofkilt
The eight bile samples were tested at varying concentrations with antisera to bile, kidney, liver, skeletal muscle and cardiac musde by double immunodiffusion. With the antibile serum, all the bile samples gave a line of precipitation corresponding to the antigen designated BT-1; half of the samples gave an additional line related to the antigen referred to as BA. This is illustrated in Fig. 1. The BA line was thinner, continued to show at higher dilutions of bile and was closer to the antiserum well than the line of BT-1. Identity of each of these antigens detected in individual bile samples was demonstrated by the complete fusion of their corresponding lines of precipitation.
The antikidney serum gave one line with all samples. The antigen related to this line w-as shown to correspond to BT-1 as follows. This line gave ateaction ofidentity with that of BT-1 given by the andbde serum (Fig. 2); and both lines were eliminated following absorption of the antisera with either bile or kidney extract.
The anriliver serum gave two lines with all samples. Them lines relate to antigens designated BT-2 and BT-3. The BT-2 line of precipitation is closer to the antiserum well than that of BT-3 (Fig. 3). These lines did not fuse with that of BT-1 or BA and, thus, appeared unrelated to these antigens. In addition, B1-2 and BT-3 separated from each other and from BT-1 and BA in immunuclcctrophoresis and Sephadcx G-200 gel filtration, as indicated below.
Antisera to skeletal and cardiac muscle were unrcactive with bile.
CMA 003307
412
Fio. 1. Demonstration of bil* samples containing antigen BT-l (a) and antigens BT-l and BA (b). Peripheral wells have twofold serial dilutions of human gallbladder bile C74-180 (a) and C7-M83 (b). Dilutions are dockwiae and Starr at 100 ms, ml in the up|>cr rfijlit well. Central wells in each plate contain antihile serum (AS-42). Its this and.succeeding tests, antisera were nonreacrive with human scrum and plasmaconstituents after specific ibsorpuon.
Ftc. 2.
Fig. 3.
Fia 2. Demonstration of identity of antigen BT-l detected by antibile and uwkidney sen. Weil l contain* antibile serum (AS-42); 2, antiludney serum (AS-38); and 3, 10" , solution of bile C74-180.
Fits. 3. Double immunodiffusion test showing bile antigens BT-2 and BT-3. Peripheral weDa contain, docwts*. two-fold serial dilutions of bile C74-IS0, starring at 100 mg;ml in the upper right wdL Central well contains antiliver serum (AS-30).
Fig. 4. Immunoelectrophoresis of bile C74-IH3. WelU in huth pUca contain 10-,, solution of bile C74-183. (a) Trough has mobile scrum (AS-42). (h) trough has antslivcr scrum (AS-30V
CMA 003308
Antigens in bile
413
Fra. 5. Sephades G-200 gel filtration of bile C74-183. See Materials and Methodi lection for detail*.
All these antigens separated from each other and moved towards the anode in Immunoelectrophoresis (Fig. 4). Their electrophoretic mobilities ranged between that ofalpha- and beta-serum globulins.
Separation of the antigens of bile was also accomplished in Sephadex G-200 gel filtration. BT-1 was detected close to the void volume ofthe effluent and BT-3, BA ami BT-2 eluted later, in that order (Fig. 5). BA was detected over a wide zone, both in immunoeiectrophoresis and gd filtntion, indicating molecular heterogeneity.
Occurrence ofantigens in tissues and body fluids
The relative amounts of lyophilized preparations of tissues and body fluids required m absorption tests to abolish the precipitin lines of antigens BT-1, BT-2, BT-3 and BA were compared--the more absorbent required, the less antigen it contains (Table 1). These results indicated that BT-1 is present in bile, kidney and urine; BT-2 and BT-3 are widely distributed mainly in liver, kidney, lung and bile. BAwasdetected in halfofthe biles examined and also in the saliva ofthree outofthe fivenormal subjects
Tabu I. Relative amounts of mom extract cad body thud preparations required for absorption of precipitin lines of
antigens BT-l, BT-2, BT-3 and BA
Minimal weight absorbent (mg/ml antiserum) effective in abdiriring pmdpidit line
AbMfbtnt
BT-1
BT-2
BT-3
BA
`Liver
U 5 5U
Kidney
20 5 20 u
Spleen
UWWu
Lung
u W 20 u
SU. minds u U U u
Heart
uUuu
Utcrua
u 50 u u
Bile
so 50 20
5
Urine*
50 U u u
Saliva*
u u u so
Antisera aliquots were absorbed with tissue extract or'body fluid preparations (up to 50 mg/ml antiserum) and tested with bile.
U - unaffected line of precipitation; \V m weakened line of precipitation.
* Obtained from live donor*.
00339
CMA
414
r,, Espinosa
T'.di.l 2. F.tTect of temnentu.-j
Temperature (30 min in PUS)
Antigen
BT-I BT-2 BT-3 BA
25`C
4
*r
36'C
-w -
70*C
--
-- -
lore
__
-f-
T
+, UoeSeeted; , putiai inactivation; complete inactivation.
tested. This distribution ofBT-l and BA was confirmed by direct immunodiffusion tests ofbody fluids and tissue extracts with the antibile serum. Occurrence of BT-2 and BT-3 could not be studied by direct testing since the antiliver serum meted with other tissue antigens not detected in bile.
Species specificity studies
In order to study the species distribution of the antigens, the antisera were absorbed with biles of various mammalian species and tested against two-fold dilutions of human bile. Absorption of the antiseta with human bile abolished reaction with all antigens (with the exception ofBA if biles not containing BA were used), thus confirming their presence in humans. In contrast, absorption with pig, dog, cat and guinea-pig biles did not significantly affect any ofthe lines of precipitation. Absorption with Rhesus monkey bile abolished only reaction with BA, thus indicating the presence ofan iimnunologically related antigen in this specio. These findings were confirmed by direct double immunodiffusion tests of the animal biles: none of the antigens could be shown, except BA which was demonstrated in monkey bile. However, immunodiffusion patients comparing the reaction of human and monkey biles showed a line of fusion with a spur consistent with partial identity or a cross-reactive relationship of the BA from the two species.
Phjsuoekrmcai properties
Treatment of bile with Pronase resulted in loss of the line of precipitation given with the antisera. In the controls with no enzyme and with enzyme but without incubation, the antigens remained motive. The control with enzyme alone was unractive. This suggests that the bile antigens are proteins or closely associated to protein.
In order to study die effect ofheating on the bile antigens, a 10% solution ofbile in PBS was incubated at various temperatures for 30 min and tested with the antisera. As indicated in Table 2, BT-1 and BT-3 were relatively susceptible to treatment; in contrast, BT-2 and BA withstood boiling temperature.
All antigen* were unaffected by treatment with neutral or alkaline buffers up to pH 10-0. Buffer at pH 5-0 partially inactivated BT-l but did not affect the ocher antigens. Treatment at pH 2-5 and 3-5 reuited in complete inactivation of BT-1 and BT-3 and partial inactivation of BT-2. BA was unaffected even at pH 2*5.
As shown in Table 3, BT-1 was precipitated at ammonium sulphate concentrations between 30 and 70% of saturation, BT-2 at 70-100% and BT-3 at 30-50%. BA precipitated over a wider range of ammonium sulphate concentrations.
Treatment with ethanol (Table 4) resulted in inactivation of BT-1; the other antigens precipitated mainly at ethanol concentrations ranging from 30 to 70%.
BT-1 and BT-3 in patients' sera
Serum samples from thirty-three patients and from forty-eight normal blood donors were examined
CMA 003310
Antigens m bile
Taju 3. Antigens in (NH*)jSO* fractions
(NH.i),S04 fractions (% sstuiwed)
Antigen 0-30 30-50 50-70 70-100 SN*
BT-1 BT-2
BT-3 BA
-++ -
+ '+ +
+T
--
-
+ +
--
++ +++
--
-
+ ++, + +, + Indicate strength of double diffusion reaction in dilution assay.
* SN a supernote of the 100% ururued lolution.
Tajlc 4. Antigens in ethanol fractions
Ethanol fractions (r/v%) Andfcn 0-30 30-70 SN*
BT-If BT-2 BT-3 BA
_*
t ++ -- ++ -
++ + +
+++, ++, +, indicate strength of doubt* diAnion reaction in dilution
* SN, supernote of the 70% ethanol precipitation, dialyzed and lyophilized.
t Ethanol suscepdble-
Tiiau S. BT-2 and BT-3 in pedants'm
Group
Number of caou Number ofcases
with ntrillsring with brcuiitmg
Number of cm*
BT-2
BT-3
Aeon hapodtis:
mntm Alcoholic cifhuo ictinhidrtJc User drrhous Obuiucrire jaundice liar upAatfCMM PlBAOM Pancreatitis Norms! subjects
S 7 5 1 4
2 2 S 2 4#
4 6 4 1 0 0 0 0 0 0
4
t
4 3
0
0
0
0
0
0
415
for the presence of the bile antigens by double immunodiffusion. BT*l and BA could not be detected in any ofthe scrum samples. As indicated in Table S, BT-2 and BT-3 were detected in sen ofmost cases with acute hepatitis but not in other liver diseases, pneumonia, pancreatitis and normal subjects. Identity of antigens BT-2 and BT-3 detected in bile and patients' sera was shown by the fusion of their lines of precipitation and by their elimination following absorption of the anriliver scrum with bile.
CMA 003311
416 E. Espinosa
t.' ~
n-
The present data have demonstrated presence in bile ofantigens
and of 'vide body distribution.
Of limited body distribution was antigen BA, detected in bile and saliva ofcertain individuals, and antigen
BT-l found to be present in bile, urine and kidney. A wide body distribution was shown by antigens
BT-2 and BT-3 which were detected in bile, liver, kidney, spleen and lung.
Antigens previously demonstrated in bile include both normal serum proteins and apparently bile-
specific proteins (Rawson, 1962; Hardwicke et al., 1964; Gausen et al., 1965; Yoon tt al., 1966; Wales
tt al., 1969; Englert tt al., 1970). The reported number of bile proteins grew with increasing sensitivity
of the techniques employed from four, by paper electrophoresis (Yerschure, 1956; Wales et al., 1969), to
up to sixteen total proteins and four specific bile proteins, by disc electrophoresis combined with
immunodiffusion and immunoeiectrophoresis (Englert et al,, 1970). Three 'bile-specific protein com
ponents' were identified in human bile by Yoon et al. (1966) and up to four by Engiert tt al. (1970) by
immunoeiectrophoresis using rabbit antihuman bile scrum absorbed with normal human serum. Since
other body fluids and tissues were not tested, these studies did not rule out the possibility that such
antigens are present in other body fluids and tissues as well as bile. Of the components identified by
Yoon et al. (1966), one (alpha-1 biliprocein) moved slower and another (biliprealbumin) faster than
serum albumin in immunoeiectrophoresis; a third component (biliproalbumin) moved as serum albumin.
One of the antigens described by Engiert et al. (1970) moved as biliprealbumin and the three others in
the post albumin zone which includes the serum globulins. The antigens described in the present work
had immunoeleczrophoredc mobilities ranging between that ofalpha-and beta-serum globulins and thus
may relate to the antigens described previously in the post-albumin zone. Antigens with albumin and
prealbumin electrophoretic mobilities were not detected in this work. Neither was evidence obtained of
antigens with strict specificity for bile. However, one bile antigen (BA) was found to be shared with
saliva only. This antigen was not searched for in saliva in a preliminary study and was, thus, considered
to be present in bile only (Espinosa, Shelton St Shaw, 1975).
The antigens described in this work separated from each other in Sephadex G-200 gel filtration and
amnKinium sulphate fractionation and, thus, appear to be distinct and different molecular entities. Both
methods are being employed for their purification and isolation. All antigens were inactivated by Pronase,
suggesting that they are proteins or closely associated to proteins. In addition, they were precipitated at
70% ethanol concentration, excepting BT-l which was inactivated by ethanol and was generally rather
labile. In contrast, BT-2 and BA were relatively resistant to boiling temperature and to add pH.
Of special interest to liver disease is the finding of BT-2 and BT-3 in the blood of perients with acute
hepatitis. These antigens are pan of a group of circulating tissue antigens of wide organ distribution
which have been found to be present in patients with liver injury (Espinosa, 1974). Two more of these
infigens, referred to as CTA-2 and CTA-3, have been recently characterized (Espinosa, 1976). CTA-2 is
a protein with a relative electrophoretic mobility of a beta-serum globulin end molecular weight in the
range of 67,000-80,000; CTA-3 moves in immunoeiectrophoresis like an alpha-1-serura globulin, is
resistant to Pronase and behaves like a protein of molecular weight of about 300,000. Other circulating
antigens detected in liver disease include the following liver-specific antigens; (a) F-antigen of wide
inletspecies cross-reactive properties (Bodmer, 1969; Roeentnund, 1971; Smith St Iverson, 1973);
(b) a protein located within the cytoplasm of hepstucytes and of molecular weight of about 190,000
(Meyer zum Biischenfelde & Miescher, 1972); and (c) LSA, a protein of electrophoretic mobility of
serum gammaglobulins and molecular weight in the range of 82,000-93,000 (Espinosa, 1973). Signifi
cance of these findings in the pathogenesis and clinical assessment of hepstins is worth investigating.
These
fhrtiild include correlations of the levels of these antigens in diseases of the liver and of
other organs and investigation of their autotmmunogenic properties. The possibility that bile antigens
ate related to autoimmune liver disease is suggested by the demonstration of ceil-fnediaced immune
response to a protein fraction of human bile in patients with primary biliary cirrhosis and active chronic
hepatitis (Eddleston et al., 1973).
CMA 003312
. Antigens in bile
417
The author wisher to thank Min Margaret VenBraun, Mrs Virginia F. I'etrcy ami Mr Gordon l- Shaw Tor usiona daring this investigation. This work was supported in part by grants from Eli tally and Company ami EL F. Goodrich and Company.
REFERENCES
UooMJt, A. (1969) Xschwcis cincs hcpatozclIuUien Shadens
mil tier Gelprazipitations methode ntit Ililfc cincs MausAuio-Antikdrpen. Path. Mirrekml. (Btsd), 33. 257. Clauses, J,, Kju, 1. Sc Dam, H. (1965) Fractionation and characterization of protons and lipids in bile. Setnd. J. elm. Ink. Invest. 17,325. Eoouston, A.L.W.F., McFaslans, I.G., Miraim, CG,, Rub, W.D. At Williams, R.B. (1973) CdMncdhued immune response in primary biliary cirrhosis to a protein fraction from human bile. Brit. nui.J. iv, 274. Engukt, E., Jk., Wales, EX, Js. & SraAtowr, R.G (1970) The proteins of human gallbladder bile with and without gallstones. Clin. ekim. Acta, 29,319. Espinosa, E. (1973) Circulating tissue antigens. II. Studies on an organ-specific antigen of human liver. Ink. Invest. 29,556. Espinosa, . (1974) emulating tissue antigens. L Tissue antigens in serum of patients with diseases involving injury of the liver and ofother otgsnaL Clin. exf. Immunol. 16, 153. Espimim, E. (1976) On two tissue antigens detected in pathologic sera. Lak. Invest. 34. 314. EviNOtA, . & Kaplan, M.H. (1968) Antigenic Analysis of human hetrt tissue. Identification of tnhgcns with
specificity restricted to hmrt and skeletal muadc in add extracts of myocardium. J. Immunol. 100,1020. EsnreaSA, E. tc Kaplan, M.H. (1970) Antigenic analysis of human heart tissue. Antigem with restricted organ distribution in add extracts of human myocardium. J. Immnutl, 105,416.
Espinosa, E., Shelton, R.N. 4: Stuw, G.L. (1973) Tuaue
specificity and properties of two bile antigens. Fed. Prtc.
34, 1033.
Hasowkxs, J., Rankin, J.G., Rum, K.J. & Patisto, R.
(1964) The loss of protein in human and Canute hepatic
bile. Clin. Sri. 26,509.
Mum not BOschdo-tloc, K.H. tc Mitsons, P.A, (1972)
Liver spedfie antigens. Purification and characterization. Clin. txf. Immunol. 10,89.
Rawson, A.J. (1962) Human bile proteins. I. Proteins
identified by antibody to human scrum. Clin. Cirm. S,
310.
Roscnmund, A. (1971) Ein levetspetifischca Antigen im
Scrum von Lesetiranken. Stkmeiz. mtd. Wider. 101,1023.
SatttotOGcn, J.J. (1955) Unc mictororitbode dc rimmuno.
rieetrophoieae. /nr. Arch. Allergy, 7,103.
Sumi, J.B. tc IvnutM, G.M. (1973) Oocurrom of liver-
spedfic antigen in adult human serum. Clin, txf, Immmnl.
13,209.
Vnstatust, J.GM. (1956) Electiw-duumognme of human
bile. Clin. ekim. Aett, 1,30.
Wales, EX, J-, Enolikt,
Jk., Wingapo, R.T.,
Maxwell, J.G. & Stevens. LX (1969) Disc dectro-
pboteria-immunodiffuaum at serum proteins in normal
human galWdadder bik. Free. See. erf. Bid, (N.Y.\
132,146.
Yoon, D+Shim, & 8c Ko, T. (1966) a'le-spedfie protein
components in human hepatic bik. J. Ink. din. Mid. 67,
640.
CMA 003313
ABSTRACTS
CMA 003314
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Dr. Kenneth M. Endicott, Executive Officer American Association of Pathologists
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PATHOU$Y
LYMPHOCYTE TRANSFORMATION TESTS IN VINYL CHLORIDE (VC) WORKERS. H. Philip Fortwengler*. Michael E. Dever*, Carlo H. Tamburro*. and Enrique Espinosa. Univ. of Louisville School of Medicine, Louisville, KY 40201
Previous reports have shown circulating immune complexes in VC workers and a tumor-associated antigen in VC-related liver angiosarcoma. This suggests immune stimulation by a tissue or plasma antigen induced by or conjugated with VC or a metabo lite. In this work, the in vitro lymphocyte reactivity for such antigens was tested in 79 VC workers including 25 with liver abnormalities, and 20 normal individuals having no ex posure to VC. The liver angiosarcoma antigen preparation in cluded the tumor-associated antigen and other tissue antigens as shown by immunodiffusion. Stimulation indices (SI) were calculated from cellular incorporation of trltiated thymidine. Mean SI in the normal individuals for antigens of angiosarcoma and normal liver tissues were 4.7 (SE1.7) and 3.8 (0.9) and in VC workers, 1.8 (0.2) and 2.5 (0.3) respectively. Mean SI for FHA and Con A in the normal individuals were 235 (35) and 209 (30) and in VC workers 201 (23) and 180 (19) re spectively. Thus, these results suggest that VC workers have a decreased lymphocyte response to antigens of liver angiosarcoma and normal liver tissues rather than the hypothesized in creased reactivity. This appears to be due to a lower ver'all lymphocyte responsiveness in these chemical workers. (Supported in part by the Manufacturing Chemists Association)
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(AILING ADDRESS OF FIRST AUTHOR (Please Print or Type) H. Philip Foriwengler...............
Univ. of Louisville Sch. Med
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CMA 003315
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, r;ti. Liver ^atho'physiolo^
'1379 FASEB
iA*AbOsS tract
SITS' ~ rilil carciriogenesis; uieaicai, "viraj
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PATHOLOGY
FACTOR VIII CONTENT AS EVIDENCE FOR ENDOTHELIAL ORIGIN OF VINYL CHLORIDE ASSOCIATED LIVER ANGIOSARCOMA (VCA). H. Philip Fortwengler*, Douglas Jones*, Carlo H. Tatnburro* and Enrique Espinosa (SPON: G. Randolph Schrodc). Univ. of Louisville School of Medicine, Louisville, KY. 40232
To ascertain the endothelial cell origin of VCA ve have looked for Factor VIII in the tumor since this factor ap pears to be specific for such cells (Hoyer et al., 1973). Frozen sections of three VCA and one idiopathic case were examined for presence of Factor VIII by indirect immuno fluorescence. Sections of angiosarcoma demonstrated a strikingly increased specific fluorescence which lined enlarged sinusoids. This intense fluorescence was easily seen on low power(lOOx) as an irregular or splotchy pat tern. Occasional strlations of linear fluorescence which did not follow hepatic cords were also present. A similar pattern of. staining was also given by the idiopathic angioj sarcoma but was-never seen in sinusoids of normal liver, These observations were further supported by the finding ^ that absorption of Factor VIII antiserum with experiment talangiosarcoma tissue resulted in complete inhibition of immunofluorescence. These findings demonstrate that VCA and idiopathic angiosarcoma lncluda proliferating cells containing Factor VIII and therefore strongly support an endothelial cell origin of this tumor. (Supported in part by the Manufacturing Chemists Association.)
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CMA 003316
CLINICAL RESEARCH *
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USE OF DYE CLEARANCE IN DETECTION OF HEPATOCELLULAR INJURY AMONG VINYL CHLORIDE WORKERS. P. Fortwengler* and C. H. Tamburro. Department of Medicine, Digestive Diseases & Nutrition Section, University of Louisville, School of Medicine, Louisville, Kentucky.
Serious hepatic injury associated with exposure to potentially harmful indus trial chemicals and the need for a sensitive method of early detection has been previously noted among vinyl chloride workers. (Creech, J. L., et al, Gastroent., 67:786, 1974). Forty-three of the 1,183 employees of this poly vinyl chloride production plant with biochemical, radioisotopic, and histologi cal evidence of liver dysfunction were evaluated using indocyanine green (ICG) dye clearance, at both the 0.5 mg/Kg and 5.0 mg/Kg dose. Percentage dis appearance rates (PDR) were determined by both blood and ear densitometry with automatic computer calculation of PDR. Liver histology was normal in 9, minor changes in 10, fat and minimal fibrosis in 14, portal fibrosis in 4, fibrosis and lobular distortion in 2, and angiosarcoma in 4. Individual bio chemical tests correctly indicated hepatic status in 80-83% of the cases with 8% false positives and 10-15% false negatives. Radioisotopic studies alone correctly indicated liver status in only 55%, with 45% either false positive or false negative. The 0.5 mg/Kg dose of ICG correctly indicated liver status in 80% with no false positives, but failed to indicate liver dysfunction in 20%. However, at the 5.0 mg/Kg dose, all cases of liver dysfunction were detected. Ear densitometry values were essentially the same as blood valu s. Ear densitometry with electronic calculator allows a dye clearance d termination over 10 minutes without drawing blood. This data demonstrates an effective iheang for early detection of industrial chemical hepatotoxicity.
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CMA 003317
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DECREASED GLUC0SE-6-PH0SPHATASE ACTIVITY IN LIVER IN VINYL CTLORIDE EXPOSED RAIS. J.T. Du* and C.H. Tasburro* (S?0N: M. Fonda) Dig. Dls. & Nutr. Sect., Dept. Med., Cancer Center, Dniv. of Louisville Med. Sch., Lou., Ky. 40201.
Increases In key glycolytic enzymes paralleling hepatoma tumor growth (Heinrich, et al., FEBS Letters, 2:145, 1974) end decreases in key gluconeogenic enzymes prior to and with the development of hepatomas (Isok, t al., Voprosy. Med. Khim 19:568, 1973) have been shown. We exposed adult SpragueDawley rats to 10,000-20,000 ppm of vinyl chloride (VC), 4-8 hrs./day, 5 days/vk. for 3-4 wks. (40-140 hrs. exposure) to , Induce liver injury and angiosarcoma formation. Glucosc-6phosphatase, a key gluconeogenic enzyme in the- liver micro somal fraction, decreased 253 over control (?<0.05 from com bined data). Other microsomal proteins and enzymes related to VC metabolism, i.e., P450, NADPH-cytochrome c reductase and mixed function oxidase were unchanged in the same microsomal fraction with no differences in either mitochondrial cyto chrome oxidase or blood transaminases. The decrease in glucose-6-phosphatase is similar to the lower gluconeogenic enzyme findings in hepatomas. This may reflect an increase in glycolysis and rlbose-5-phosphate production associated with de novo purine biosynthesis prior to tumor development, inhi bition in enzyme synthesis, or increased breakdown due to VC exposure. Work is under way to determine the mechanism. The decrease in glucose-6-phosphatase may he an early biochemical lesion usable as an indicator of liver injury associated with Che subsequent development of angiosarcoma. (B.F.Goodrich Grant) Supported by NCI Contract tfNOl-CN-55212
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ELEVATED GLUTATHIONE CONTENT, GLUTATHION^^^SA/#?AND GLUTATHIONE REDUCTASE IN LIVER OF RATS EXPOSED TO VINYL CHLORIDE Ou, J.T.* and Tamburro. C.H.* (SPON: McGeachin, R. L.) Dig. Dis. & Nutr. Sect., Dept. Med., Cancer Center, Univ. Lou. Med. Sch,,Lou., Ky., 40232
Vinyl chloride (VC) is believed to be metabolized to chloroethylene oxide (CEO) and chloroacetaldehyde, and detoxified by way of glutathione. Rats were exposed to 28,000 ppm VC, 7hrs/ day, 5days/wlt for 4 and 6 weeks, the activity of glutathione epoxide-S,-transferase (GEST) was elevated 30 to 54Z over normal control and air control (9.71+ 0.6$ vs 7.52+0.97 and 6.30+ 0.68) respectively. However, The activity oTglutathione aralkyl-S-transferase (GAST) was not significantly elevated until 6 weeks of exposure to VC. The content of reduced glutathione was also elevated 45Z in the VC treated group and the activity of the glutathione reductase, the enzyme to re generate glutathione from the oxidized form was elevated 50Z. These results demonstrate that VC exposed rats have the capa city to maintain glutathione reductase activity and glutathione concentration for detoxification. Further, it suggests that the primary route of VC metabolism is initial oxidation to CEO and then detoxification by GEST directly. With longer exposure and probable saturation of the direct route, there is greater rearrangement of CEO to chloroacetaldehyde, and de toxification with glutathione as supported by the delayed in duction of GAST (Supported by a grant from Manufacturing Chemists Association).
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Sarua Bile Acids (S3A) Screening Far Clerical Haparacatrizity. Garv LI33* and Carlo H, T^r.burro* (3?QN: Villian Vaddall). NIQSH Rebar: Taft Laboratory, Cir.cin., CH. * Liver .Tssaara.i Canter, Div-. Occupational Health, Dapcs. of Medicine i Co*nmunity Health, Univ. of Louisville, Lou., Ky. 40292.
Standard liver tests have limited ability to detect latent liver disease (Environ. Health Partcact. 19? 1; -1:117-112', . Serum bile acids are more sensitive indicators of liver in jury. During the medical surveillance of 1C00 chamicai weth ers 67 liver biopsies were investigated for histological evi dence of chemical injury (Gastroenterology 1979; 77:A33); 15 had chemical liver disease (CLD), 27 noncheaical liver disease (NCLD) & 25 had normal biopsies (NBX). Fasting SBA-cholylgly cine (CG) & conjugates of cholic acid (CCA) were studied by 1251-radioimmunoassay in these groups and 416 "normal" work ers. Mean + S.E.M. for CG in the OLD, NCLD, NBX & normal groups were"95.17 + 28.75, 27.25 + 4.43, 34.60 + 7.13 & 14.9 + 0.88 ug/ml, respectively. Analysis of variance shoved sig nificant differences (p<0.035) in the 3 biopsy groups; p<0.001 for all 4 groups. The CLD values were significantly differ ent in CG levels of the NBX (p<0.02). No significant differ ence in CG levels in NCLD and NBS groups; CCA- showed similar results. Fasting SBA showed promise in detecting latent chemical liver injury.
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CMA 003320
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7
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Absorption Secretion Motility Uver/Biliary/Bile Salt G.l. Hormones Morphology Clinical Immunology/Microbiology
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7T5SWE AND URINARY GLYCOSAMXNOGLYCANS (GAG) CHANGES IN HEEAXIC FIBROSIS C. E. Kupchella. J. 0. Jarvis. K. L. Curran. R. A. Greenberg, and C. H. Tamburro Cancer Cencer and Digestive Diseases and Nutrition Section, University of
Louisville School of Medicine, Louisville, Kentucky. GAG's are felt to play an important role in the collagen
fibril formation and collagen bundle stabilization. It has been assumed chat hepatic fibrogenesls contributes little to the total body connective tissue and would not be reflected In urinary excretion of GAG degradation or syn thetic products. We have previously found, however, that increased urinary GAG's occur in humans with cirrhosis, hepatitis, and hepatic angiosarcoma (Kupchella, C.E., Tamburro, C. H., Clin. Res. 25:329, 1977; Curran, K. L., Kupchella, C. E., Tamburro, C. H., Cancer (in press), 1977). In the present study, changes in urinary and hepatic GAG's were measured in rats with CCL4-induced hepatic damage. Highly significant increases (P <.001) in total GAG's and in the hyaluronic acid (HA), chrondrotin sulfate (CS), and the heparin (H) fractions were found in hepatic tissue after three weeks and persisted through nine weeks of ex posure. Histological examination after three weeks showed hepatic necrosis with extensive fatty metamorphosis without hlstochemical (Trichrome-Alcian Blue-PAS) evidence of fibrosis. Control hepatic tissue GAG levels were 31+5 ug (of uronic acid) per gram of dry defatted liver. CCL4 treated livers showed a 2 to 4 fold increase in GAG levels; 81.4 pg at 3; 98 ug at 6; and 113 ug/g at nine weeks, re spectively. Increases occurred mainly In the CS and H frac tions. The urinary CS fraction was significantly (P <".05) elevated over the nine weeks of exposure; the HA fraction was elevated during the first two weeks only, and the H fraction excretion appeared to be directly related to CCL4 injections. These data support our previous observations in humans and demonstrate that urinary GAG excretion pattern changes occur before hlstochemical evidence of collagen formation and suggest that urinary GAG patterns may be a useful indicator of early hepatic fibrogenesls.
MAILING ADDRESS OF PRINCIPAL AUTHOR Carlo H. Tamburro, K.D. 511 South Floyd Street Room 535 MDR Building
Louisville, Kentucky
40201 zip ----------
If, in the conduct of these studies, human subjects wetc exposed to risks not required by their medical needs, the author affirms that the Study was approved by an appro priate committee, or, if no suchcommittee was available and informed consent was needed, it was obtained in accordance with the principles set forth in "The Institu tional Guide to DHEW Policy on Protection of Human Subjects".
CMA 003^^
CUBICAL RESEARCH
Abstract Reproduction Form
TYPE name, address, and telephone number of author who should receive correspondence in 2sx A and ssmrlete 3o:c B.
Telephone
~"
(Area soda) o(ee
(Aim code) home
Charles . Kupchella. Ph. 0._____ Associate Director, Cancer Center
213 MQR Building_________________
Health Sciences Center----------------Louisville* Kentucky 4Q2Q1
CHECKPrtfortd Sub-Spteiatiy Oamfteaaon:
___ Cardiovascular Clinical
____ Epidemiology
Clinical ___ Pharmacology ___ Dermatology
- Endocrinology* -- Gastroenterology ___ Genetics -- Health Care Research ___ Hematology
Immunology A Conn. Tissue
____Infectious Disease
-- Metabolism* ___ Oncology ___ Pulmonary ___ Renal Electrolyte
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fitliiilitie Han. thyrocWaw-
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URINARY CHONDROITIN SULFATE FRACTION PATTERNS IN HEPATIC ANGIOSARCOMAC. E. Kupchella, K. L. Curran. and C. H. Tamburro. Cancer Center,
University of Louisville, Louisville, Kentucky. This study was undertaken to evaluate the usefulness of urinary
glycosamlnog1yean patterns In the detection of hepatic angiosarcoma
and in monitoring the course of this disease. Glycosamlnoglycans ex-i tracted from 24 hr urines from 2 patients with angiosarcoma of the liver and from normal controls were separated as cetylpyridintum com
plexes into "hyaluronic acid," "chondroltin sulfate," and "heparin" fractions. These fractions were further purified by anion-exchange chromatography. The "chondroltin sulfate" fraction isolated from angiosarcoma patients consistently demonstrated an Increase in the amount of glycosaminoglycan eluted In 1.25 M NaCl and a concomitant decrease In the 1.5 M NaCl elutlcn peak. This "shift" was apparently
related to the course of the disease and was unaffected by chemo
therapy. As indicated by the following results, the ratio of 1.25 M to 1.5 M elution peaks may be of value In monitoring the course of angiosarcoma: 2 normal controls, .364 and .316; angiosarcoma (pre chemotherapy), .843; angiosarcoma (post-chemotherapy), .971; angio sarcoma (advanced), 5.00. Characterization of the 1.5 M and 1.25 M NaCl elution peaks by hyaluronldase susceptibility and comparison witf elution patterns reported In the literature suggest that the observed shift was from chondroitin 4 and/or chondroltin 6 sulfate to heparan sulfate. Preliminary data indicate that the excretion pattern in vinyl-chloride-associated liver injury other than angiosarcoma is characteristically different from patterns associated with hepatitis, cirrhosis, or metastases to the liver. These observations may be related to progressive connective tissue proliferation In angiosarcoma
IMPORTANT
H* isstractioni accompanying this form must ba followed COMPLETELY for all abstracts which ara to appear in CLINICAL RESEARCH. Ab stracts which do not conform either will be re typed by the publisher at a-cost of SI5.00 to the author, or rejected.
Revised June 1976
CMA 003322
THIS FORM AS WELL AS THE FORM LETTER OF TRANSMITTAL MUST BE SIGNED BY AMEMBER
MEMBER'S SIGNATURE S
CLINICAL RESEARCH
Abstract Reproduction Form
TYPE name, address, and telephone number of author who should receive correspondence in Box A and complete Box B.
Telephone (502) 588-5253
(Ana code) office
(502) 895-2955
(Am code) home
A Name
Address
Carlo H. Tamburro. M.D.----------------------------
(falvgralty * Louisville Cancer Center 511 South Floyd Street
Room 535 MDR Building-----------Louisville, Kentucky 40201
B Date
hyaMt (J10.00)
Piifrimi ofdar . 17-1185______
CHECKfrtftmd Sub-Sptcisity Cttaifleathm:
____ Cardiovascular Clinical
- Epidemiology
Clinical ____ Pharmacology
____Dermatology
____ Endocrinology*
____Gastroenterology
____Genetics t Health Care Research
____ Hematology Immunology A
____ Conn, Tissue ____ Infectious Disease
____Metabolism* ____ Oncology ____ Pulmonary ____ Renal A Electrolyte
'Traditionally, Endocrinolor? lie* indudad paper, dmlinf with the thyroid, adrenal and pituitary flanda, rod fonada. while ab stract! deeiiof with the parathy roid*. calcium and pMwhOM matahoUam. honee, thyrooataiao iun, diebetee, insulin, |Mifaa. and irowth hormone have been conmderod under Mrtebolinw.
URINARY GLYCOSAMINOGLYCAN EXCRETION PATTERNS IN CHEMICALLY INDUCED LITER INJURY AND CANCER C. E. Kupchella*and C. H. Taaburro**, Concur
Canter, University of Louisville, Louisville, Kentucky. Glycosamlnoglycans (GAG) ore essential compounds of connective tissue (CT) matrix and are Increased with CT proliferation. Urinary GAG pat terns vere studied in 9 Individuals with vinyl chloride (VC) Induced chemical injury, 2 VC induced angiosarcomas, 8 viral hepatitis, 6 alco holic cirrhosis, 7 aon-hepatic cancers, and 9 controls. Hepatic histo logical and electron microscopic (EM) studies were obtained In all but normal controls which were studied biochemically, radloisotoplcally, and physically. Urlnaa were analyzed for creatinine, total GAG, and uronlc acid content. GAG levels (ug uranic ecid/mg creatinine) In con trols were-3.2 + .4, In VC exposed 4.1 4, and in alcoholic livar dis ease 5.1 + 0.8. In contrast. In angiosarcoma they were 7.6 + 1.6 and hepatic metastasis, 13.8 + .9. Total GAG's were further separated Into hyaluronic acid (HA), ehondroitln sulfate (CS) and heparin (H) frac tions. Although no significant differences were found In total GAG's 78Z (7/9) of VC exposed had positive CS and negative HA and H fractions in contrast to 9Z (3/32) of the other cases. Further characterization by anion-exchange chromatography showed a shift in the CS fraction composition. Total GAG's eluted at 1.25 M NsCl, were Increased and at 1.50 M NaCl decreased. These changes became more pronounced as the disease developed. Enzyme digestion Indicates that 1.25 M fraction Is heparan sulfate (HS). EM studies showed Increased sinusoidal collagen. Since HS is associated with blood vessels, its increased urinary excre tion in early VC Injury and angiosarcoma (vascular Injury and sinusoidal cell cancer) may be used as an early Indicator of chemical injury and liver cancer formation.
IMPORTANT
Tbs instructions accompanying this form must be followed COMPLETELY for all abstracts which are to appear in CLINICAL RESEARCH. Ab stracts which do not confotm either will be re typed by the publisher at a cost of $15.00 to the author, or rejected.
Revised June 1976
CMA 003323
THIS FORM AS WELL AS THE FORM LETTER OF TRANSMITTAL MUST BE SIGNED BY A MEMBER
MEMBER'S SIGNATURE . ii&fH. J.&W'
V.
Check the most appropriate category
below:
Absorption
Q Secretion Mociiity Z Liver/ Biliary/ Bile Salt G.L Hormones Morphology Clinical Immunology/ Microbiology
9 Publish this abstract in GASTRO ENTEROLOGY at a cost O/S25.00 (S30.00 if billing required) 81 Check payable to the American Gastroenterological Association enclosed. Bill me--instructions enclosed.
a Do not publish this abstract in GASTROENTEROLOGY.
10
.Type Abstract in Space Below
TISSUE AND URINARY GLYCOSAMINGLYCANS IN TRANSPLANTABLE jfl HEPATOMAS. C. E. Kupchalla, K. L. Curran. E. Drake. J. Kennedy, and C. .i. T--aourro. Cancer Cancer, and Division of Digestive Diseases and Nutrition, University of Louisville, School of Medicine, Louisville, Kentucky.
t The purpose of this investigation was to evaluate: a)
:the glycosaminoglycans (GAGs) in different behavioral/
histological types of interrauscularly transplanted hepa
tomas, b) GAG patterns in tumor tissue in relationship to
degrees of fibrosis and necrosis, e) the GAG changes in the
livers of tumor-bearing animals, and d) urinary GAG ex
cretion as a function of tumor growth. Three types of
Morris hepatomas, 7777, 5123tc, and 9618A, which differ in
-rates of growth, metastatic potential, fibrosis, and
necrosis, were studied. Urinary and tissue GAGs were ex
tracted as cetylpyridinium complexes and measured as uronic
!acid. Tissue GAGs were also evaluated hlstochemically
.using alcian blue staining with and without enzyme pre-
:treatment. Tumor tissue exhibited four- to six-fold
greater GAG levels in the hyaluronic acid (90 +10, 91 +
12, and 111+9 vs. 25 + 3 vg uronic acid/g dry liver, re
spectively) and chondroitin sulfate (261 + 29, 217 + 51,
'and 208 + 22 vs. 47 + 7 yg uronic acld/g, respectively)
ifractlona than normal liver; tha heparin fractions did not
differ significantly (31+7, 17+4 and 67 + 11 va. 39 +
10). Tha livars of tumor-baaring animals exhibited
~
slightly greater hyaluronic acid levels than normal liver
Moreover, increased urinary GAG excretion was evident aft
two weeks in animals bearing fast-growing tumors. The GAG
'tissue levels in fast vs. slow-growing tumors were not sig
nificantly different. This further supports our previously
(reported studies of urinary GAG excretion in human hapatlc
angiosarcoma (Curran, K. L., et al., Cancer 40 (6): 3050- ,
3053) in suggesting that urinary GAG analyses may b useful
in the detection, screening and diagnosis of hepatic cancer.
TYPE name, address, and telephone number of author who should receive correspondence:
Name Charles E. Kupchalla, Ph.D., Associate Director, Cancer Center
213 MDR Buildinz. University of Louisville, P. 0. Box 35260, Louisville, Ky.
Address --
------ " - -------------------------- '
40232 ~
Telephone (502) 588-5245 ....--------------------------------------------------------------------------------------------
IMPORTANT
The principal author affirms that the material herein will not have been previously published or presented at any
meeting of a national society and that if in the conduct of these studies, human subjects were exposed to risks n t re
quired by their medical needs, that the study was approved by an appropriate committee or, if no such committee was
available and informed consent was needed, it was obtained in accordance with the principles set forth in The Institu
tion* Guide to D11EW Policy on Protection of Human Subjects."
CMA 003324
Check the most appropriate category bel w:
Absorption Secretion Motility O Liver/Biliary/Bile Salt C.I. Hormones Morphology Clinical Immunology/Microbiology
S Publish this abstract in GASTRO ENTEROLOGY at a cost ofS25.00 (S30.00 if billing required)
B Check payable to the American Gastroenterological Association enclosed.
O BUI me--instructions enclosed.
Do not publish this abstract in GASTROENTEROLOGY.
Type Abstract in Space Below
11
'URINARY glycosaminoglycan patterns in human HEPATIC ANGIO- 1
ISARCOMA, HEPATOMA, AND IN WORKERS AT RISK FOR ANGIOSARCOMA. (
Ik. L. Curran, C. E, Kupchella, J. Sandoz, and C. H.
1
jTamburro. Cancer Center and Division of Digestive Diseases
and Nucrition, University of Louisville, School f Medicine,
iLouisville, Kentucky. |
t <
{ A previous study reported an abberatlon in glyeosamlno- [
'glycans (GAGs) eluted from anion-exchange columns with 1.25j
|and 1.5 M NaCl in the urine of patients with hepatic angio
sarcoma. A controlled pilot study examined urinary GAG
^patterns in workers at risk for angiosarcoma.- Six indi- |
jviduals with a history of high vinyl-chloride exposure and ' ^documented liver disease were paired with individuals with I
|a high exposure index to vinyl-chloride but n clinical
j
jliver disease. Similarly six persons with low exposure I
i(but abnormal liver function were paired with low exposure/
normal liver function individuals. A 24-hour urine was
,
collected from each individual and the GAGs analyzed by
1
anion-exchange chromatography. Individuals with clinically
active liver disease at the time of this study were found ;
'to have urinary GAG excretion patterns which were similar 1
!to those described in angiosarcoma. No significant dif- |
jferences were found between high vs. low vinyl-chloride
'exposure or between those with inactive liver disease and
[those with normal liver function. GAG excretion was also ,
!studied in an additional hepatic angiosarcoma and human
1
'hepatoma and confirm the reported urinary changes. These
(findings support the concept that urinary GAGs are in
creased only in active hepatic disease and may be useful in,
evaluating the degree of activity at the various stages of
liver disease in humans.
1
i
TYPE name, address, and telephone number of author who should receive correspondence:
------- Charles E. KtinchaM*. Ph.D.. Associate Director. Cancer Center.---------------------------
__ 213 MDR Building, University of Louisville, P. 0.-Box 35260,'Louisville, Ky.
AoQrcss
--
i ii
... "
40232
Telephone (502) 588-5245----------------------------------------------------------------- -------------------------------------- --
IMPORTANT
The principal author affirms that the material herein will not have-been previously published or presented at any
meetinp of arnationa1 sncietv and 'bat if ;n f h*
, ,<. 'V. 'e stud.ie.s,.human sub'-
Kposed to risks not re-
CMA 003325
J
CLINICAL RESEARCH
Abssrac: Reoroduction Form
'YrE name, addreu, and telephone number o;'
iuih-jr who snet.id receive correspondence in Box
cr.d cemsiete Boxec 3. C and 0.
.eieenune 5C2
533-52^5
i Area coU*> jias*
:02 itadc;
A
.name _
Address
Charles . Kupchella Cancer Cancer University of Louisville Louisville, Xy. 40232
^U
This abstnc: is u:sni::*a
American Federation far Clinical '.asaiich
'rums of arganuacioci, isite:d :.-am At (am
jt
1
239-1313
3 (Se* Rule IS)
3a:s ____
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D
CHECK single svasrtcuLTr CLASSIFICATION:
Cardiovascular* -- so.: (
Clinical Epidemiology......... __ Clinical Nutrition................... __
Clinical Pharmacology .... __
Dermatology............................... --
Endocrinology (see Rule S) __ Gastroemerotogy................... __
Genetics.....................................
Health Care Rrsearch......... ......... HamitoiOfY ............................ __
Hypertension ..........................
Immunology Rheumatology _
Infectious Oisease................ .......
Metabolism (see Rule S)... Oncology...................................... X
Pulmonary.................................. -
Renal & Electrolyte................ ---
; 'Per abstracts tubmrttsd to Cardio| vaseular only, idea iwgle subcatcfory j and enter code no. (lmi in space abovei
(1) Cimcal: (il Sasic Somcx (3) Elec*
^ephysiofogy-Dysrhythmies: Mi Echotardietraphyi (Jl Radiology-Radio* nudrict: (41 Other. Subciassifieatton is designed to awl in .-tvieweif process i cnlv tad is independent of program | veiemion.
TYPE ABSTRACT HERE/BE SURE TO STAY WITHIN BORDER
GLYCOSAMINCGLTCAN CHANCES ASSOCIATED WITH HEPATIC TUMORS: THE CONTRIBUTIONS 0? REGENERATION AND NECROSIS. C, S. Xuachella. S. M. Se<*k**-* J. 5. KannedV,* and E. Espinosa*. Cancer Center and Department of Pathology, University of Louisville, School of Medicine, Louisville, Xentueky.
Although glycosaoinoglycans (GAGs) have been shown to be elevated In many types of anInal and human tumors including hepatic tumors, the causa end significance of these changes In neoplasia are still open questions. Regeneration and necrosis are operative In hepatic cancer and the purpose of rm investigation was to evaluate the GAG changes associated with hepatic regeneration and hepatic necrosis* Regeneration was induced in male Sprague Davley rats by partial henateccooy and hepatic GAGs were evaluated at 4, 3 and 12 days post operatively. Necrosis was induced by: a) ligating the medium lobe, b) by resecting and placing median lobes in the peritoneal cavity and c) by resecting median lobes and incubating them in viero in sterile saline. Analyses were carried out after 3 days of treatment. While regenerating livers exhibited GaG levels that were not statistically different from sham operated controls or aon-aperatad controls, in vivo-' necrosis was accompanied by 3-d fold increases in tissue GAGs. These data suggest that necrosis may make a substantial contribution to the elevated GAG levels found in some tumors.
CIin.Rw. Z't{S)t3&
PLEASE CHECK ABSTRACT CAREFULLY FOR APPEARANCE BEFORE MAILING
CMA 003326
BOTH THIS FORM AND THE FORM LETTER OF TRANSMITTAL MUST BE SIGNED BY A MEMBER (RULE 2)
Charles . Kupcheila, ?h.D.
i pleat* type naml
Revised May 197?
MEMBER'S SIGNATURE:
fl/nrt icainJ pttouc hcacth /urociffncwsi
oecemss^. IS7S
Oieso
3097
Early Detection of Disease in Individual! Ex posed lo Vinyl Chloride.
Richard Crtcnbtrg, MO. and Carlo Tornburro, MO, Vnivtriity of Lomui/U, Louijvillc, Kentucky
This is a collaborative comparison study of the effectiveness of ultrasound, nail bed capillary stujy and urinary giycosnmmoglycan excretions in vinyl chloride workers
with biochemical dysfunction or histopatholopically documented injury.
It represents an effort to detect early mor bidity in vinyl chloride workers. Included is Dr. Maricq's method of investigating capil laries of the middle and distal phalanges of the fingers, including the nailfold, as a screening test for early changes from vinyl chloride exposure. Another new method is Dr. Taylor's "grey scale" ultrasonographic method which has not yet been widely adopted for diagnosis of liver disease. The University of Louisville group reported that the first indicator of liver changes occurred in the vascular sinusoids and was reflected by the appearance of mucopolysaccharides in the urine.
The resuits of the massive clinical study in Louisville should soon be able to indicate whether more sensitive criteria of early dis ease may be forthcoming, especially from the liver function testing. The special value of Che capillary and ultrasound method re main doubtful at this time for early detection of the effects of exposure to vinyl chloride.
13
193
i
CMA 03327
Prwnt.-Mton choice: J Ullonn j_j,
or J'ostcf Position `j
SC1ENTIHC PAPER
Underline name of author to notify and give
Telephone (Area) 502-588-5341
_______
Department of Pathology, University of Louisville School of Medicine,
P.0. Box 40232,
Louisville, Kentucky
--
--
------ ------
----------
" 46232
7ip _
Abstract -- Double space.
Because unfixed liver is rarely available for analytical studies, appraisal ot
the extent of collagen must be made from appropriately stained sections of live
biopsy material leading to judgemental as well as sampling error. We have de
veloped a computer assisted morphologic technique to evaluate the distribution
of collagen in liver biopsy material. We examined multiple biopsy samples from
patients dying suddenly with no history of liver disease to establish normal
values. A Hewlett-Packard 9864-A digitizer and 9815-A micro computer were used
to quantitate areas of trichrome stainable collagen within the biopsy samples.
Random area selection and statistical analysis proved to be Important consider
ations in determining the experimental model and these factors were readily in
corporated into the calculator program. Stainable collagen estimates in normal
liver varied from 0 to 6.11 (mean - 1.251) in patients with no evidence of li>*r
disease and showed considerable variation even in different biopsies from the
same patient. As anticipated, subcapsular biopsies had more collagen than deep
biopsy; however, the specimens from several deep biopsies often had significant
variation in collagen content. Differences in central, mid-zonal and portal
collagen could be obtained using this method. The computer assisted morpholog
ical technique for evaluating hepatic collagen appears to be readily adaptable
to clinical studies. This study of normal liver
considerable care must
h takpn hofnre the clinical diagnosis of jsignifleant fibrosis can be made. . --
(Limit abstract to 2SO words or less)
(OVER)
CMA 003328
American Association For The Study of Liver Diseases ABSTRACT FORM
15_
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Foroffice uk)
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B IMPORTANT
The principal author affirms that the material herein: I) will not have been previously published or presented at any national meeting of a national so ciety: 2) that if human subjects were exposed to risks not required by their medical needs, the study was ap proved by an appropriate committee or. if no such committee was available and informed consent was needed, it was obtained in accordance with the principles enunciated in "The Institu tional Guide to DHEW Policy on Pro tection of Human Subjects"; or 3) any animal studies conform with the "Guiding Principles in the Care and Use of Animals ' of the American Physiological Society.
EARLY HEPATIC HISTOLOGICAL ALTERATIONS AMOK CHEMICAL
(VINYL MONOMER) WORKERS. C.H. Tamburro, L. Htkk. and H.
Popper, Division of Digestive Diseases and Nutrition and
St. Anthony Hospital, University of Louisville, Louisville,: Ky., and Stratton Laboratory for Study of Liver Disease, |
Mt. Sinai School of Medicine, New York, N.Y-
Industrial vinyl chloride exposure is asociated with
tiepatic subcapsular, portal, and perisinusoidal fibrosis
and hyperplasia of both sinusoidal cells ani hepatocytes.
jEarlier histological studies, mainly on autspsy material, i
lindicated that focal mixed hyperplasia (of hepatocytes and jsinusoidal cells) is the early histologic alteration indi
cative of exposure. To substantiate this observation and
.its potential use in screening workers, liver biopsies from
,55 persons were Investigated in double blind duplicative
.fashion; 34 were workers exposed to chemicals with hepatic
(biochemical abnormalities, and 21 were a coeparison group
composed of 8 non-exposed persons and 13 exposed workers
without hepatic abnormalities who had biopsies for non-
(liver related reasons. Of the exposed workers with abnor
malities, 12 (35%) had a hepatic lesion consistent with
*
{exposure; 6 (18%) had focal hepatocytic hyperplasia; 6 (18%)
had focal mixed hyperplasia. In contrast, ly 5 of the ;
.comparison group (2 exposed and 3 non-exposei persons) had :
Similar findings; 1 exposed and 2 non-exposed had only
cal hepatocytic hyperplasia. The other closed worker j
Ed focal mixed hyperplasia as did the other non-exposed i dividual who, subsequent to the biopsy, was found to have j jangiosarcoma. Thus, only 19% of the comparison group
demonstrated hepatic lesions with chemical exposure, half
of whom had worked with chemicals* Of the 55 bi pales, 22
were re-read double blindly 2 to 4 times ow a 2-year
period. In addition, 9 of these individuals had second or
third biopsies also read double blindly. Delicate readings
were identical in 86%, 9% had 1 positive and 1 questionable \ reading, and only 5% were read differently. Focal hepato
cytic hyperplasia, in addition to the previously described
mixed hyperplasia, appears to be the earliest identifiable changes consistent with chemical exposure aod seem to be
precursors of angiosarcoma. They are useful in the screening of chemical workers.
'
C Mum- Carlo H. Tamburro. M.P.. Professor of Medicine 511 S. Floyd, Room 535
Address
Louisville, KY. 40202
t 19/9
of Pnnor.il *MiltHr|
Telephone. Office. 588-5252 (502) Home._895-^955 (502)
___ __ Ufc.i uvuJe)(area
003329
16
Chloroacetaldehyde-induced Damage to 3acillus subtilis. A.D. Laumbach, U.N. Streips* and J.L. Wong. Bureau Foods, FDA and U. Louisville, Louis-
viLle, !Cy.
Chloroaeecaidenyde (CAA), a proposed metabolite of vinyl chloride meta bolism, has been shown to be mutagenic in the Salmonella assay system, and to specifically inhibit the growth of a recombination-deficient mutant of Bacillus subtilis (Ellmore, et_ al BBA, 442: 405, 1976).
We have examined further the biological activity of this compound. First, CAA caused a significant increase in induced mutations to streptomy cin resistance. Using B. subtilis 168, the relative mutation frequency (treated 5mM CAA/control) was 13.6, while using an her mutant of B. subtills the frequency was 14.2. Secondly, a survey of the available repair-deficient mutants of B_. subtilis revealed, that the only strains sensitive to CAA were of the rec-genotype. Furthermore, the several rec-mutants, shw three types of response to CAA. Strong killing by CAA (inhibition of growth of 10 mm or more) was exhibited on the recA, recB, rec-4 (GSY1616), and recD27 (GST1627) strains. Intermediate killing (3mm-8mm) was shown with strains bearing the recE, recF, and rec-13 (BD246) loci. All other strains examined (recC, recH. mtc-41, uvr, her, polA. as well as several repair-proficient cultures) grew in the presence of 1.1M CAA.
These studies are part of an ongoing program sponsored by the MCA to determine the molecular basis for vinyl-chloride induced carcinogenesis.
cma 3330
17
Chloroacetaldehyde-induced Damage to Bacillus subtills. A.D. Laumbach, U.N. Straips*, and J.L. Wong. Bureau Foods, FDA, and University of Louisville, School of Medicine, Health Sciences Center, Louisville, Ky. 40232 (USA). Chloroacetaldehyde (CAA), a proposed metabolite of vinyl chloride metabo lism, has been shown to be mutagenic in the Salmonella assay system, and to specifically inhibit the growth of a recombination-deficient mutant of Bacillus subtilis (Ellmore, et al., BBA, 442:405, 1976). We have examined further the biological activity of this compound. First, CAA caused a significant increase in induced mutations to streptolycin resistance. Using B. subtills 168, the relative mutation frequency (treated 5mM CAA/control) was 13.6, while using an her mutant of B. subtilis the frequency was 14.2. Secondly, a survey of the available repair-deficient mutants of B. subtilis revealed, that the only strains sensitive to CAA were of the rec-genotype. Furthermore, the several rec-mutants, show three types of response to CAA. Strong killing by CAA (inhibition of growth of 10 mm or more) was exhibited on the recA, recB, rec-4 (GSY1616), and recD27 (GSY1627) strains. Intermediate killing (3mm-8mm) was shown with strains bearing the recE, recF, and rec-13 (BD246) loci. All other strains examined. (recC, recH, mct-41, uvr, her, polA, as well as several repair-proficient cultures) grew in the presence of 1.1M CAA. The effects of CAA on the biological activity of DNA molecules in vitro are being studied. These studies are part of an ongoing program sponsored by the Manufacturing Chemists Association to determine the molecular basis for vinyl-chloride induced carcinogenesis.
CMA 003331
r.L..j ; I-. ,.,i
c
2 or 5
13
INHIBITION 0? INTERFERON INDUCTION AS A SCREEN FOR THE CARCINOGENIC '
POTENTIAL OF CHEMICALS. Gerald Sonnenfeld,* Mary Carol BameJ, and Uldis N. Scrtipa, Department of Microbiology and Immunology, Univ. of Louisville School of Medicine, Louisville, Kentucky 40232.
Type I interferon was produced after challenge of mouse embryo fibroblasts with Newcastle disease virus. This production of interferon could be sharply reduced by pretreatment of the cells with the known car cinogens benz-o-oyrene, aflatoxin, 2-aminofluorine, and the #4 fraction of. tobacco smoke condensate. This finding suggested that inhibition of interferon induction (I-I-I) may serve as an indicator for the carcino genic potential of chemicals. We tested the screening potential of this assay by testing two chemical analogs, methylmethanesulfonaca (MMS) a car cinogen and mutagan and ethylmethanesulfonate (EMS) a oon-careinogenic mutagan. Both of these chemicals are active in the Ames Salmonella assay but can ba separated in "SOS" induction assays such as the Comptest. In the I-I-I assay, MMS was highly positive while EMS showed no lnhbltion of interferon induction. Thus, the I-I-I assay appears to have the potential to screen for carcinogens. Preliminary results using the carcinogen ehloracetaldehyde and its non-carclnogenlc analogs chloroethanol and chloroacatic acid support this idea. Following further verification of the dis crimination potential of the I-I-I assay, this test could became an Integ ral part of a comprehensive battery of tests for chemical carcinogenicity.
.A r>v* .*
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T::is V -V , ;lie Abr.v.. nrigin-.w
v. sue >!'
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.in.; Gerald Sonnenfeld, Ph.D. Department of Microbiology_
and Immunology, University of Louisville School of Medicine, N.ealth Sciences Center Louisville, KY 40232.
. i! liUc.'i :
;i = - (s* i- 1
I'.S.A.
CMA 003332
19
Reproduction Copy tor PROGRAM AND ABSTRACTS of the 30TH ANNUAL MEETING OF THE TISSUE CULTURE ASSOCIATION, INC.
Properties of 14 Week Maintenance Cultures of PLC/PRF/5 Cells. P.B. JOHNSTON*, E. Espinosa, S. Chia and S. Caple. Univ. of Louisville, Louisville, Ky 40232______ This established cell line was originally described as being short lived with in a given passage, with considerable cell loss by day 6 to 8. However,after 80 passages, we found that culturing in glass roller bottles at 0.15 RPM allowed maintenance for at least 14 weeks with cells exhibiting excellent morphology without sloughing. After treating monolayers with Hoechst 33258 DMA stain, intense cytoplasmic fluorescence was seen in a proportion of the cells, possibly a function- of the subviral hepatitis B genome. HBsAg of culture supemates was monitored and solid phase RIA assay revealed 31 to 47 ratio-units/0.2 ml after 2 to 14 weeks in medium with 10% fetal calf serum. ' The 14 week old cultures were extremely well adapted to maintenance in serum, free medium for 14 additional days when supplementing with 100 ng/ral of insulin, in contrast to 1 week cultures which survived well for only 5 days without serum.. The HBsAg-titers of supernntes from these 1 week or 14 week cultures, were very similar to the previous harvests in 30% scrum. In addition, both young and 14 week cultures were similar in their rate of acid production; and in that both elaborated scrum albumin, fibrinogen, transferrir and alpha-2 macroglobulin, the proteins tested to date.
CMA 003333
ABSTRACT must BE RECEIVED AT SOCIETY OFFICL liv TUESDAY, DECEfiBER 19
p!e* eonuder ihts abstract for inclusion in ihe tentatively fisted
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Indicate below -.he numbers and litlas of sessions in which your abstract
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u ilO-____ Title Livar-8a4hophy sio4ogy----------------
13/3
FASEB Abstract
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2C
00 NOT FOLD Tins FORM
Mill to: American Association of Immunologists 9S50 Rockville Pike Betticsda, Maryland 20014
IMMUNOLOGY
LIVER-SPECIFIC F ANTIGEN IN TRANSPLANTABLE HEPATOMAS HAVING DIFFERENT GROWTH RATES. Enrique Espinosa, Sue Chia*, Sam Cagle* and Charles Kupchella*. Dept. Pathology and Cancer Center, Univ. of Louisville School of Medicine, Louisville, KY 40232
In the course o studies of antigenic changes associated with liver neoplasia we measured the relative concentration of liver-specific F antigen in fast (7777), slow (9618A) and medium (5123tc) growing Morris hepatomas in comparison with its concentration in normal adult rat liver. F antigen was solubilized from each tissue by aqueous homogenization. The supernatant containing the antigen was then tested by a double diffusion dilution assay capable of detecting a mini mum of 1-2Z the concentration of antigen present in normal rat liver. The F antigen antiserum used was prepared ac cording to Fravl and Lindenmann by immunizing C5A mice wieh BALB/e mouse liver extract. F antigen was undetectable in the fast growing hepatoma and ranged from less than 22- to 10Z of the normal liver concentration in the slow growing one. The medium growing hepatoma showed similar or higher concentration than normal rat liver. Thus, -the level of F antigen in these tumors does not appear to correlate with their rates of growth. (Supported in part by the Manu facturing Chemists Association)
AU compounds that arc designated by code or initial letters must be identified adequately in the abstract, e g., MJ-1999: 4-<2-i*opropylammo-I-hydroxyeihyl) tnelhanesulfonani-
lide hydrochloride.
MAILING ADDRESS OF FIRST AUTHOR (Please Prim or Type. Provide full name rather than initals.)
Enrique Espinosa, M.D.
.... 511. South .Floyd.S.tre.et........................
.... Louisville.......KT___ Zip 40.232............. Telephone No.: Area CodfP.2.. #A88-5525..............
Each Abstract Form submitted MUST BE SIGNED by a member of the AMERICAN ASSOCIATION OF IMMUNOLOGISTS.
Enriqpe Espinosa
_____
IMempw'i Nam*; PtoaM Prim crjfom. PyfnSe tuft
/1 L&tn-sc f iMembnr'i Signature!
Member's telephone no.: Area Code.. 502..............#. 588.-55.25-----
CMA 003334
ABSTRACT MUST 8E RECEIVEO AT SOCIETY OFFICE BY TUESDAY, DECEMBER 19
Pleiie consider this abstract Tor inclusion in the tentatively listed minisymposium,
u 43 Chemical Carcinogenesis
Indicate below the numbers and titles of sessions in which your abstract migh be programed (see Topic Category List);
1* 430 Ti.u Liver FathophvsiologY--------------21 4Q2_____Title Tumor Biology -- ---------------------------
409 " TUnor Sptifciiic An Ligetis
19/9 FASEB Abstract Form
21
Mail to: Dr. Kenneth M. Endicott. Executive Officer American Assoeiati n of Pathologists 9650 Rockville Pike Bethesda, Maryland 20014
________________............................................................. ,--
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& Porter presentation Slide presentation Indifferent
If your first choice is unavailable, you will
C? Accept the alternative Withdraw the abstract
16 mm. films (silent or optical sound) are permitted if essential to 10-minute slide session presentation.
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Submit justification by letter to Society Office, with abstract.
important
Before you complete this form: Sec the enclosed rules for elitibility of papers. See sample abstracts and typing instruc tions on reverse side. Use enclosed Check List for preparation of abstract.
t PATHOLOGY
iTWO LIVER ANTIGENS UtTOgtETHaairfii
LINE OF
TRANSPLANTED HEPATOMA (MORRIS HEPATOMA 7777). Enrique
Espinosa, Sain Caple*, Charles Kupchella* and Sue Chia*.
Dept. Pathology and Cancer Center, Univ. of Louisville
School of Medicine, Louisville, KY 40232
During investigations of antigenic changes in liver tumors
we examined fast (7777), medium (5123tc) and slow (9618A)
growing Morris hepatomas for presence of liver antigens.
Analyses of normal liver and hepatoma tissue saline extracts
were performed by immunodiffusion methods using rabbit anti
serum to rat liver extract absorbed with pooled normal rat
plasma. Hepatoma 5l23tc and 9618A gave immunoelectrophoretlc
patterns similar to normal liver. In contrast, hepatoma 7777
showed 2 arcs of precipitation missing. This was confirmed
by the finding that after absorption of antiserum with hepa
toma 7777 two lines of precipitation given by normal liver
extract persisted whereas absorption with extract of normal
liver, hepatomas 5123tc or 9618A abolished all lines of pre
cipitation. The liver antigens found to ba absent in hepa
toma 7777 were characterized as proteins relatively unstable
to heating and acid pH and unrelated to liver-specific F antigen. In Sephadex G-200 and Bio-Gel A-5m columns these antigens eluted as proteins of approximately 51,000 and 240,000 daltons respectively. The fact that 7777 is the fastest growing and least differentiated of the tumors studii suggests a possible functional relationship between the absent antigen and these properties. (Supported in part by
the Manufacturing Chemists Association)
The original typed copy of this abstract form (for reproduction by photo-offset) with
- 8 photocopies, - one set of author index cards, - three abstract identification cards, - and return Program Confirmation Postal
All compounds that are designated by coda or initial letters must ba identified adequately in the abstract, e.g,, MJ-1999: 4-(2-isopropylarnino-l-hydroxyethyl) methanesulConanitide hydrochloride. -
must reach the Society office NO LATER THAN TUESDAY.DECEMBER 19.
Each Abstract Form submitted MUST BE SIGNED by a member of ihe AMERICAN ASSOCIATION OF PATHOLOGISTS.
MAILING ADDRESS OF FIRST AUTHOR (Please Prim or Type. Provide full name rather than initals.)
Enrique Espinosa, M.D.
511 South Floyd Street
Enrique Espinosa
IMMiender's Name. FPlaease Pint owjvpe fovtde tun iwn>.l
7.A
(Member's Sgneturei
^502
588-5525
Member's telephone no.: Area Code.................. ......... #.................
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CMA 003335
AilUJi
v
International Association l*or The Study 0t` ! he Liver
Abs:;:ct Submission Dates: IASL June IS, 1980
AASLD Jui>' 1' ABSTRACT FORM
Abstract submitted to: AASLD
IASL
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:or?5'?(?nd?r.ce in 3cx D, ar.d complete Boxes A and 3 ,md C.
CATEGORIES - Indicate category of choice
Immunology
2. Collagen Fibrosis
3. Morphology
4. Viral Hepatitis
5. Chronic Hepatitis
Metabolic Liver Disease
Complications of Liver Diseaw
8. Alcohol and the Liver
9. Bile Acids
10. Bilirubin Cholestasis
.11. Pediatric Liver Disease
12 Miscellaneous
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B IMPORTANT
The principal author affirms that the material herein: I) will not have been previously published or presented at any national meeting of a national so ciety: 2) that if human subjects were exposed to risks not required by their medical needs, the study was ap proved by an appropriate comminee or. if no such committee was available and informed consent was needed, it was obtained in accordance with the principles enunciated in "The Institu tional Guide to DHEW Policy on Pro tection of Human Subjects": or 3) any animal studies conform with the "Guiding Principles in the Care and Use of Animals" of the American
l Sifnature of Principal Author)
TYPE ABSTRACT BELOW. BE
. aTAY WITHIN 3CRDES
OXIDATIVE AND DETOXIFYING ABILITY OF LIVER MESENCHYMAL' PARENCHYMAL CELLS IN THE METABOLISM OF XENOBIOTICS Du. J. and Tamburro, C.H., Liver Research Laboratories Dept, of Medicine, University of Louisville, Louisville
The metabolism of xenobiotics, by the liver most often
volves oxidation via mixed function oxidase (MFO) and s
hydryl detoxification with glutathione. Hepatic toxlci
end carcinogenicity are modified by these two pathways.
Vinyl monomer (e.g. vinyl chloride) exposure is associ
with liver parenchymal cell (hepatocycic cell, HC) coxi
and mesenchymal cell (sinusoidal cell, SC) carcinogenic
even chough the hepacocyte is the main cell for xenobic
oxidation. The metabolic ability of these two cell gro
was assessed by isolation of SC using pronase digestion
end HC using collagenase profusion. Viability assessed
90% by trypan blue exclusion and cross contamination es
mated (< 1*) by pryuvece kinase activity. MFO activity
(demethylacion benzptaetamine), glutathione transferase
(E) using (1,2, epoxy-(P-nitro nitrophenoxy) propane as
substrate, glutathione transferase A,C and E (A) using
nltrobenzyl chloride) as a substrate and glutathione
tase (GR), were determined in subcellular isolated H
SC fractions. Results based on protein content (N mole,
min/mg protein) were:
E A GR MFO
SC 42.9+17
18.5+6
47.4+2 7.49+2.
HC 82.5 + 11 215.0 + 61
65.0 + 7 16.0 + 5
and activity In oole/lO* call were:
E SC 1.16 HC 65.6
A 0.5 220.
GR 1.28 52.
MFO 0.026 4.7
These results demonstrate both the greater average, as v es total, cellular ability of HC to oxidize xenobiotics More importantly, it demonstrates an increased ability t detoxify the xenobiotic's toxic metabolites. This great ability may account for less severe HC injury and play < important role In preventing HC malignant traasformatior In contrast, SC ability to oxidize but its lesser abilit to decoxlty xenoblotic may account for SC's potential fc
D Oif1" H- Tanhurro. M.D.---------------------------------Division of Digestive Diseases & Nutrition
AddresSil South Floyd - MUK Bldg. Urn. 535-----------
Louisvillei Sameoaky 40392---------------------------
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Marcn imo
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CMA 003336
ASPET/SOT 1982
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Deadline (or Bsedpb May Tt IMS
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23
Toxic, Carcinogenic & Safe Exposure Levels in Vinyl Chloride Induced Hepatic Angiosarcoma. Carlo H. Tamburro* and Richard A. Greenberg* (SPON; William Waddell). Depts. of Medicine & Community Health, Univ. of Louisville, Lou., Ky. 40292.
Vinyl chloride (VC) induced hepatic angiosarcoma (HA) has
rapidly decreased since 1974. The relationship of latency & duration of exposure was studied in 21 North American (NA) cases and 62 worldwide (WW) reported cases; 92Z of NA & WW cases had long exposures (LE) (10-33 yrs); 7 cases (8Z) had short exposures (SE) (3.5-7 yrs). The mean duration in both LE & SE groups was 18.5 yrs. with 2 peaks at 15 & 25 yrs. Deaths from HA began in 1955, peaked in 1976 & rapidly fell thereafter. HA peaked in Canada (CA) in 1973 and USA 1974, France (FR) 1976, & Germany (GE) 1978. Operations began in CA in 1941 & USA 1939-44; FR 1941-57, & GE 1952-60. Exposure levels reported in 1940's of ^2000 ppm; in 1950's ''.200-500 ppm, in early 1960's `'.50-500 ppm, late '60's & early '70's `'.50-250 ppm, & 1-10 ppm after *74. No relationship was found in total average exposures (TAE) range of 50 ppm; 200-1000 ppm range showed a direct relation of lower TAE to shorter latency, while higher TAE (1000-2000 ppm) had longer laten cies. The data suggests VC has a biological threshold level, an optimum carcinogenic level and subcarcinogenic toxic level for occurrences of HA.
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CMA 003337
PREPRINTS
003338
EARLY HEPATIC HISTOLOGICAL ALTERATIONS AMONG CHEMICAL (VINYL MONOMER) WORKERS
1 23
Carlo H. Tamburro, Laszlo Makk, and Hans Popper l Liver Research Center, Department of Medicine
21 and St. Anthony Hospital, University of Louisville
3
Louisville, Ky., Stratton Laboratory for Study of Liver Diseases, Mt. Sinai Hospital fo Medicine,
New York, New York
1
Portions of this work supported by NCI Contract No-l-CN-55212 and the Manufacturing Chemists Association Grant VC7.0
333S
ABSTRACT Earlier histological studies of i-ndustrial vinyl chloride exposure, obtained mainly on autopsy material, indicated that focal mixed (hepatocytes and sinu soidal cells) hyperplasia is the earliest histological alteration indicative of exposure. To substantiate this observation and its potential use in screening workers, 93 liver biopsies from 78 persons were investigated in double blind duplicative fashion; 35 were exposed chemical workers with hepatic screening tests abnormalities, and 13 were exposed workers without hepatic abnormalities who had liver biopsies for non-liver related reasons. A comparison group consisted of 30 individuals who were not chemical workers, but had liver biop sies for non-hepatic related reasons during the same time period. Of the exposed workers, 23 (48%) had a hepatic lesion consistent with exposure; 17 (35%) had only focal hepatocytic hyperplasia; six (13%) had focal mixed hyper plasia or more advanced lesions. In contrast, only five of the comparison group had similar findings; four (13%) had only focal hepatocytic hyperplasia and one (3%) had focal mixed hyperplasia and sinusoidal dilitation. On a siAsequent biopsy, this individual was found to have angiosarcoma and a history of using hair spray containing vinyl chloride as propellant. Ten individuals had 28 multiple biopsies also read dottle blindly, and 10 individuals had 23 readings of the same biopsy; 21/23 (91%) duplicate readings and 27/28 (96%) multiple biopsy readings in the same individuals were identical. Only 18% of either duplicate and/or multiple biopsy readings had disagreements in their biopsy assessment. Focal hepatocytic hyperplasia, in addition to the previously described mixed hyperplasia, appears to be the earliest identifiable change consistent with chemical exposure and both lesions are present prior to the . development of angiosarcoma. These lesions can be consistently identified and are useful in the screening of chemical workers for evidence of exposure.
1
CMA 003340
INTRODUCTION Industrial vinyl chloride and other vinyl monomer exposure is associated with various hepatic histological abnormalities. These include subcapsular, portal, and peri sinusoidal fibrosis as well as hyperplasia of both hepatocytes and sinusoidal cells. Early histological studies, mainly on autopsy material, had shown focal mixed hyperplasia (hyperplasia of hepatocytes and sinusoidal cells) to be an early histological alteration associated with vinyl chloride exposure (1,2,3). To substantiate this observation and determine its potential use in medical surveillance screening of the exposed workers, liver bioosies from 73 individuals were studies in duplicate blind fashion to determine 1) if these early histological findings were associated with extensive vinyl chloride exposure, and 2) if these histological findings occur in non-exposed popula tions or were associated with other diseases.
MATERIALS AND METHOOS Liver biopsies from 48 vinyl monomer chemical workers with and without hepatic biochemical abnormalities were investigated. All 48 chemical workers had had hepatic biochemical studies performed on an annual or semi-annual basis. These included aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AP), total bilirubin (TB), gamma glutamyl transpeptidase (GGT), prothroutln time (PT), and Indocyanine green clearance (ICG). In addi tion, history and physical examinations, liver-spleen scans, and abdominal plain films had been performed annually. Thirteen of the chemical workers had hepatic biopsies for non-liver related reasons while 35 had biopsies performed because of screening biochemical and/or liver-spleen radioisotopic scan abnor malities.
CMA 003341
A group of 30 individuals who were not chemical workers but had undergone
abdominal surgery with liver biopsies, were used as a comparison population.
All of the comparison population's liver biopsies were performed during the
same three-year period, at the same hospital, by members of the same medical-
surgical team, with the informed consent of the individuals. This group had
similar hepatic biochemical studies with the exception of the GGT and ICG
clearance. None had a history of extensive exposure of working with halo-
genated hydrocarbons, although one patient had a history of household contact
with vinyl chloride via commercial home products.
Pathology
Earlier experiences with autopsy and animal material from vinyl chloride
associated angiosarcoma have recognized certain hepatic lesions in the non-
tumorous area of the liver parenchyma (
). They include:
1. Hepatocytic changes consisting of foci of enlarged hepatocytes
with increased amount of cytoplasm, and large hyperchromatic
nuclei (Figure 1). These cells are intermixed with hepatocytes
of normal and smaller sizes and create focal, indistinct nodular
areas (Figure 2a). These areas are often associated with very
slight increased sinusoidal dilitation and focal increase in the
reticulin framework illustrated best by silver impregnation
(Figure 2b).
2. Sinusoidal lining cell changes consisting of an increase in cell
number associated with nuclear changes, particularly conspicuous
in areas of sinusoidal widening. This proliferation of sinusoidal
cells involves (a) Kupffer cells (macrophages) with PAS-positive
granules; (b) fibroblasts with elongated, almost rectangular
nuclei with loose vesicular chromatin patterns and inconspicuous
4
CMA 003342
nucleoli with 2 rede rats arcunt of cytoplasm which reacted on PAS staining and pars is tad afcar diastasa reaction. These cells are interpreted as activated fibroblasts, are associated with an increase in fat storing sinusoidal cells and augmented peri sinusoidal fibrosis tissue (Figure ). 3. Fibrotic changes consisting of an excel! of irregular connective tissue in the periportal zone, frequently arranged around proliferating bile ductules, and focal thickened subcapsular accumulation of corrective tissue into the parencyma (Figure 7). These histological lesions are believed to be the three earliest hepatic findings associated with vinyl monomer chemical injury. The hepatocytic changes are referred to as focal hepatocytic hyperplasia or FHH. The sinu soidal cell changes (sinusoidal cell hyperplasia) associated with the hepatocytic changes are referred to as focal mixed hyperplasia or FMH. For purposes of this study, early fibrotic changes were not classified since the majority of liver biopsies were of needle type, which could not be evaluated for subcapsular changes. The liver biopsies were coded and read blindly to identify (1) histologi cal evidence of hepatic disease; (Z) any characteristics of non-chemical injury excluding steatosis; (3) steatosis with or without fibrosis and, (4) evidence of chemical Injury identified by the following histological findings: a) focal
00^4'
6
hepatocellular hyperplasia; b) focal increased reticulum associated with the hepatocytic hyperplasia; c) peri sinusoidal fibrosis; d) focal hyperplasia; e) focal mixed hyperplasia associated with increased reticulum deposition; f) sinusoidal cell activation; g) sinusoidal dilitation; h) portal and capsular fibrosis; i) sinusoidal dysplasia; and, j) hepatic angiosarcoma.
The presence of focal hepatic cellular hyperplasia with focal increases in reticulum, in the absence of other evidences of hepatocellular disease or steatosis, were considered the minimum presumptive evidence of chemical exposure. The presence of focal mixed hyperplasia with increased reticulum and/or perisinusoidal fibrosis was considered evidence of chemical injury of a more advanced stage. Sinusoidal cell activation and dilitation of the sinusoids were con sidered evidences of chemical injury of an even further stage of advancement. The presence of subcapsular fibrosis, (on wedge biopsies only) and/or increases in both portal and sinusoidal fibrosis, with sinusoidal cell activation and sinusoidal dilitation was considered the most advanced stage of chemical injury characteristic of vinyl chloride or vinyl monomer exposure. Finally, sinu soidal cell dysplasia and/or evidence of malignant transformation, constituted definitive evidence of chronic vinyl chloride exposure and the terminal stages of injury.
Work and exposure histories were available for all the chemical workers. The work histories provide a total and average exposure data for 22 chemicals based on rank order exposure estimates. These exposure work histories consisted of an estimate of exposure to each of 22 different chemicals for all of the 350 job classifications used since the start of the chemical plant. Each of the chemicals exposure was ranked on a scale of zero to six for each of the 22 chemicals. These exposure ranking estimates were done separately
CMA 003344
for each job for each year based on the best available information and i-.d-stria' e/.pertise. Zach 'worker's cumulative exposure to each of tne 22 chemicals was based on the various job classifications he/she held during their employment. A detailed explanation of this system and an actual in-the-field demonstration of the ability of this system to identify work-related liver injury (angiosarcoma) has been published elsewhere (4,5).
RESULTS Thirty-seven percent (13/35) of the exposed workers with screening test abnormalities had hepatic lesions consistent with chemical exposure. Among the exposed workers without biochemical abnormalities 23% (3/13) had hepatic lesions consistent with chemical exposure. In the non-worker comparison group none of those with normal biochemical screening tests and 17/19 (89%) with abnormal biochemical screening tests had hepatic lesions consistent with chemical expo sure. Of the remaining two, one had focal hepatocellular hyperplasia; the other had focal mixed hyperplasia and early peliosis hepatis. This latter individual was later found to have angiosarcoma possibly from vinyl chloride hair spray exposure. The former individual had no history of chemical exposure.and/or alcohol consumption, but did have hepatobiliary tract disease in the form of biliary stones. Table X lists the hepatic lesions found in those with and without biochemical abnormalities for the entire group. Reproducibility An evaluation of the reproducibility of these biopsy readings was carried out in 17 individuals who had 32 biopsies. Seven individuals had only one biopsy (2 needle, 5 wedged) and 10 individuals had their biopsies read in dupli cate. Four had needle biopsies with 9 readings and 6 had wedge biopsies with 14 readings (Table 2).
CMA 003345
8
A comparison of the reproducibility of the biopsy readings is shown in Tables 3, 4 and 5. Table 3 illustrates the high degree of consistent readings between multiple biopsies in the same individual. In only one individual was one of the four biopsies read differently--the wedge was read differently from the three needle biopsies.
Table 4 makes a comparison between readings of multiple needle biopsies or multiple wedge biopsies from a single individual. In these cases there was consistent agreement in all readings.
Table 5 illustrates the consistent readings of the same biopsies over the three-year period. All the needle biopsy duplicate readings and 12 of the 14 wedge duplicate readings were the same.
At least 96X (43/45) of all readings, whether duplicate or from multiple biopsies, provided reproducible and consistent findings. Correlation of Histological Lesions With Exposure
Biopsies from all the chemical workers were divided into three categories on the basis of final diagnosis:
1) individuals with no evidence of histological liver disease (N) 2) individuals who had liver disease but no evidence of chemical injury
(LD)
3) individuals who had chemical liver injury identified by the histolog ical criteria specified (CLI).
A comparison was made between the average vinyl chloride exposure ranking of each worker and his/her final histological diagnosis. The exposure rankings were not known to those making the final histological determination at any time during the three year period. As illustrated in Figure 6 the group of workers with evidences of chemical liver injury had the highest percentage of individuals with the highest ranking of exposure to vinyl chloride. Previous studies of
CMA 003346
9
this worker cohort had shown that all the cases of angiosarcomas had an average vinyl chloride exposure ranking (AER) of 3.5 or greater. AER's of 3.5 or greater occurred in 452 of the CLI group. In contrast, those with liver disease (ID) alone, only 222 had a vinyl chloride exposure rating of 3.5 or greater and in the chemically exposed workers with no evidence of liver disease, 322 had a rating of 3.5 or greater. Biochemical Studies
A study of the biochemical abnormalities among the two histological groups of chemical workers with evidence of liver disease is illustrated in Figure 7. The five screening tests with the best degree of sensitivity and specificity in identifying latent liver injury were reviewed. Indocyanine green clearances, at the 0.5 mg/kg dose, provides the most sensitive and the most specific of the laboratory screening study, followed by the alanine amiontransferase and aspartase aminotransferase, gamma glutamyl transpeptidase and alkaline phosphatase (6). However, specificity for chemical Injury appeared to be associated more with abnormalities in the alkaline phosphatase, which was far more frequently abnormal in workers with chemical liver disease than In those with non-chemical liver Injury. In contrast, the ALT, AST, GGT, and ICG were more frequently abnormal in those workers with liver disease of a non-chemical origin.
DISCUSSION Figure 8 provides the most likely progression in the development of vinyl chloride and other vinyl monomers hepatic injury and cancer development. These findings confirm those previously reported by Thomas and Popper (2) in their original pathological studies of vinyl chloride associated hepatic angiosarcoma and hepatic injury. Focal hepatocytic megalocytosls associated with focal increases in reticulum structure, in the absence of other evidence
003347
10
of acute or chronic injury, appear to be the earliest change associated with chemical exposure. Subsequently, there occurs perisinusoidal fibrosis associated with a proliferation of fibroblasts and/or its precursor cell, the Ito cell. In later stages sinusoidal cell activation occurs involving both the macrophagic and endothelial lining cells. These changes are associated with focal sinusoidal enlargement. In the late stage mixed hyperplasia (hepatocyte and sinusoidal cells) becomes prominent, followed by sinusoidal cell dysplasia with palasading of cells, and finally malignant transformation.
Our data demonstrates that focal hepatocytic hyperplasia is the earliest consistently identifiable histological finding in industrial workers exposed to vinyl monomer chemicals. The very limited occurrence of these findings in non-chemical workers and the fact that focal mixed hyperplasia, a more advanced lesion, was only found in chemically exposed workers and in a nonchemical worker with vinyl chloride exposure (via hair spray), adds further confirmation that these lesions are related to prolonged or repeated periods of chemical exposure.
Whether these lesions should be viewed as precursors to the development of cancer or only as an early reflection of the degree and duration of chemical exposure cannot be determined at this point in time. The unchanging and stable status of screening studies over a seven year follow-up period and the histo logical similarities among the serial biopsies of these workers suggest that these early lesions are non-progressive when the affected individuals are removed from exposure (7).
The presence of sinusoidal cell dysplasia, however, has been associated with the later development of angiosarcoma as illustrated in one of our cases and may represent a true precancerous or a non-reversible lesion.
CMA 003348
1
The reproducibility in identifying these histological lesions is quite high. Under double blind conditions there was consistent histological identification of chemical injury in both duplicate readings of single biopsies as well as single readings of multiple biopsies in the same individual. Inconsistency appears to occur more frequently among the duplicate readings of wedge biopsies and between wedge and needle biopsies than between duplicate readings of needle biopsies or readings of multiple needle or wedge biopsies in the same individual. This may be due to the increased time and attention needed for wedge section review in order to determine the absence or presence of these lesions anywhere in the specimen. There are, however, some pitfalls that require caution. The quality of the histological preparation is of vital importance. Technical artifact, excessive thickness, tom or fragmented spec imens will greatly reduce the ability to correctly identify these lesions. The use of silver impregnation for assessment of the reticular structure is very useful in verifying focal areas of hepatocellular hyperplasia. The presence of fatty infiltration and/or chronic disease (hepatitis, granuloma, etc.) may prevent the identification of these lesions. We were, however, able to correctly identify the presence or absence of these early lesions in the six individuals who also had a concomitant granulomatous process (four individuals with granuloma were repeatedly read as negative and two individuals with gran uloma were repeatedly read as positive for chemical liver Injury).
The more frequent elevation of alkaline phosphatase in those individuals with histological evidence of chemical injury may provide some guidance in sequential uses of laboratory screening tests. During the first phase, tests with the greater sensitivity for identifying liver Injury, such as the ICG and ALT can be used. Positive results can be followed up by using tests of greater specificity, such as the alkaline phosphatase, to further identify those at high risk of chemical injury.
CMA 003349
CONCLUSIONS Focal hepatocellular hyperplasia, in addition to the previously described focal mixed hyperplasia, appear to be the earliest identifiable changes consistent with chemical exposure. These histological lesions are useful in identifying high risk exposed chemical workers as part of a medical screening surveillance program. Biochemical studies may help identify which individuals warrant a liver biopsy for further identification of the cause of the liver abnormalities.
CMA 003350
REFERENCES 1. Popper H, and Thomas L3. Alterations of liver and spleen among workers exposed to vinyl chloride. Annals of the New York Academy of Sciences 1975; 245:172-194. 2. Thomas LB and Popper H. Pathology of angiosarcoma of the liver among vinyl chloride-polyvinyl chloride workers. Annals of the New York Academy of Sciences 1975; 246:268-277. 3. Gedlgk P, Muller R and Bechtelsheimer H. Morphology of liver damage among polyvinyl chloride production workers. A report on 51 cases. Annals of the New York Academy of Sciences 1975; 246:278-285. 4. Greenberg RA and Tamburro CH. Exposure indices for epftemiological sur veillance of carcinogenic agents in an industrial chemical environment. Journal of Occupational Medicine 1981; 23:No. 5, 353-358. 5. Greenberg RA and Tamburro CH. Monitoring exposure to hazardous chemicals in an industrial setting: a method of demonstrated utility. Journal of Occupational Medicine ,198
13
6. Tamburro CH and Greenberg RA. Effectiveness of federally-required medical laboratory screening in the detection of chemical liver injury. Environmental Pt^pectives, 1981 , 41:117-122 7. Tamburro CH, Davidson CS, Fisher Mi, et al. Medical surveillance for chemical hepatotoxicity. Guidelines for Detection of Heoatotoxicity cue to Drugs and Chemicals. Davidson CS, Leevy CM and Chamberlain EC (ed.) U.S. Department of HEW, NIH Pub. No. 79-313, 1979, Chapter 5; 60-80.
CMA 003351
OXIDATIVE AND GLUTATHIONE-RELATED DETOXIFYING ENZYME CAPABILITIES IN HEPATOCYTES AND NONHEPATOCYTES OF RAT LIVER
2
Julie T, Ou, D.S. Eades, and Carlo H. Tamburro Liver Research Center, Department of Medicine and Division of Occupational Health, Department of Community Health
and Cancer Center University of Louisville, School of Medicine
Louisville, Kentucky 40292
CMA 003352
2
ABSTRACT Liver is the main organ in the body with the capacity to metabolize xenobiotics. Mixed function oxidase (MFO) and glutathione transferase(s) are the major enzymes involved. The activities of MFO (demethylation of benzphetamine), glutathione transferase(s) (glutathione ^-epoxide transferase, GEST, 1,2-epoxy-[-nitrophenoxy] propane as substrate; and glutathione S-aralkyl transferase, GAST, -nitrobenzyl chloride as substrate), and glutathione reductase (GR) were determined in the subcellular fractions of isolated nonhepatocytes and hepatocytes. The nonhepatocytes were isolated by pronase digestion and the hepatocytes by collagenase perfusion. The viability of the cells were assessed by trypan blue exclusion and shown to be over 90% viable in the hepatocyte and nonhepatocyte fractions. Cross-contamination of isolated cells was estimated by the relative distribution and specific activities of the L- and M2-type pyruvate kinase isoenzymes and was found to be insignificant. The specific activity based on protein content showed that the nonhepatocytes had about 7% GAST activity, 50% GEST and MFO activities, and 73% GR activity compared to hepatocytes. Based on activities per million cells, the nonhepatocytes had approximately 1/450 GAST activity, 1/100 MFO activity, 1/60 GEST, and 1/40 GR activity as compared to hepatocytes. Based on distribution of enzyme activity in hepatic cells per gram liver, the nonhepatocytes had less than or equal to one hundredth the activities of MFO, GAST, GEST, and GR as compared to hepatocytes. This study demonstrates that the nonhepatocytes have the capacity to metabolize and detoxify xenobiotics but that they are significantly less capable than the hepatocytes in oxidation and glutathione-related detoxification.
CMA 003353
3
INTRODUCTION
Liver is the main organ in the Dody in regard to the"~ffletaoo ism of xenobiotics including drugs and carcinogens. Hepatocytes are thought to be the cells that are mainly responsible for this metabolism, but little is known about the role of nonhepatocytes. These cells, mainly endothelial and Kupffer cells, because of their anatomical location may interact with xenobiotics before they even enter hepatocytes. Thus, it is important to compare nonhepatocytes to hepatocytes as to their enzymatic capability to oxidize and detoxify xenobiotics. In this study, we concentrated on the enzymes for oxidation (mixed function oxidase, MFO) and glutathione-related detoxifying enzymes (glutathione S^-epoxide transferase, GEST; glutathione ^-aralkyl transferase, GAST; and" glutathione reductase, GR) in the microsomal and soluble fractions of isolated nonhepatocytes vs. hepatocytes as well as in whole 1iver tissue.
MATERIALS
Oxidized and Reduced Glutathione (GSSG and GSH respectively), Metrizamlde, Bovine Serum Albumin (8SA Cohn Fraction V), NADPH, AOP, NADH, Phosphoenol pyruvate (PEP), DNAse, FructoseJ,6-diphosphate and Lactate dehydrogenase (pyruvate kinase free) were obtained from Sigma Chemical Co., St. Louis, MO. Gey's Balanced Salt solution was purchased from GIBCO, Grand Island, NY. l,2-Epoxy-3-(p-n1trophenoxy) propane from Eastman Kodak Co., Rochester, NY., p-nitrobenzyl chloride from Matheson, Coleman and Bell, Norwood, OH. Benzaphetamine Hydrochloride was a gift from The Upjohn Co., Kalamazoo, MI. Collagenase Type II was purchased from Worthington Biochemical Crop., Freehold, NJ. Pronase E was purchased from E. Merck, Darmstadt, Germany. All other chemicals were reagent grade and were obtained from commercial sources. Double distilled water was used throughout the experiment.
Tests for Cell Purity and Integrity: The purity and integrity of cells isolated were tested by 1 ight microscopy (phase contrast), by trypan blue exclusion, and by the relative distribution and specific activities of the Land M2-type pyruvate kinase isoenzymes. The M2-type pyruvate kinase (in the nonhepatocytes) is not activated by the addition of fructose-1,6-diphosphate but the L-type pyruvate kinase (solely in hepatocytes) Is activated 11-fold (5).
Cell Homogenization and Fractionation: A Polytron homogenizer was used at setting b for 60 sec to obtain cell homogenates. The homogenate was then centrifuged at 8000 g for 10 min in a refrigerated Sorvall centrifuge. The supernatant was centrifuged at 100,000 g for 60 min at 4C in a Beckman ultracentrifuge with a swinging bucket rotor. The rotors were equipped withr microadaptors to enable the centrifugation of samples of 1 ml or less.
Sn2yme Assays: The rate of GSH conjugate formation was determined for glutathione S-transferases. P-Nitro benzyl chloride was the substrate for GAST with E-1900 M-Tcm*` at 110 nm; 1,2-epoxy-(p-nitrophenoxy) propane was the substrate for GEST with E*510 M*'cnr' at J60 nm. Glutathione reduc
CMA 00335*
4
tase was determined by the reduction of oxidized glutathione, GSSG, as measured by the disappearance of NADPH (6). Mixed function oxidase was estimated by measuring the disappearance of NADPH in the NADPH dependent demethylation of benzphetamine (7). All asays were done using the appropriate soluble or microsomal fractions of freshly isolated cells. The activities were linear functions of protein concentration and of time.
Protein Determination: Before homogenization, the cells were washed with Gey's balanced salt solution without BSA to completely remove the BSA contained in the perfusion medium. The protein content in the soluble, microsomal and homogenate fractions were then determined by Lowry's method (8).
METHODS
Animals: Sprague-Oawley male rats (300-400 g) were used.
Cell Isolations: Hepatocytes were isolated by a collagenase perfusion method (T). The liver was perfused in situ in a perfusion chamber, first with Krebs Hensleit bicarbonate buffer (TH66) without calcium ion (pH 7.4) followed by KHBB with the addition of 0.02% (w/v) collagenase, 4 mM calcium and 2% bovine serum albumin for 40 min. The flow rate was 14 ml/min. at 37C, and constant aeration was applied with 95% 02-5% C02- After perfusion the liver was blanched completely, excised, rinsed in KHBB, blotted dry, and weighed. Glisson's capsule was removed, the cells were shaken loose by gentle agitation in KHBB with 2% BSA, and collected by centrifugation at 50 g for 5 min.
The nonhepatocytes were isolated essentially by the method of Mills and Zucker-Franklin (2) modified by Knook and Sleyster (3). The liver was first perfused with Gey's balanced salt solution (3 min), followed by the addition of pronase (0.2% w/v, 3 min) and then digested with pronase (0.2%, 60 min). In order to minimize DNA induced cell aggregation, 0.5 mg DNAse was added to the pronase digestion step. The digested tissue was filtered, and the cells collected by centrifugation at 300 g (3 min), washed and differentially centrifuged with concentrated Metrizamiae (1400 g, 15 min) to remove red blood cells.(4) The cells were counted on a hemocytometer.
RESULTS AND DISCUSSION
Cell Viability and Purity: The cells used for the determination of enzyme activities in this study were shown to be greater than 90% viable, and there was essentially no hepatocyte contamination in the nonhepatocyte preparation as judged by the pyruvate kinase activation method (Table 1). In pure hepatocytes, pyruvate kinase is activated eleven-fold by the addition/of fructose-1,6-diphosphate (1 mM) In nonhepatocytes, the activity is only slightly activated showing essentially no hepatocyte contamination (5).
Enzyme Activities: The GEST, GAST, GR and MFO activities from the soluble and microsomal fractions of isolated cells and from liver were determined and the specific activities are shown in Table 2. The specific activities in the enzyme-
003355
5
isolated hepatocytes are higher than those obtained from the fractions of wnole liver homogenate (Table 2) suggesting that the collagenase treatment does not appreciably affect the enzymes studied. The nonhepatocytes had about 7% GAST acti.ity, 50% GEST and MFO activities and 73% GR activity as compared to hepatocytes; these results are based on protein content..
There have been no reports about the glutathione-related enzyme activities in nonhepatocytes. Cantrel and Bresnick (9) have studied benzpyrene hydroxylase in various hepatic cells by determining the fluorescence of the reaction product, 8-hydroxy benzpyrene, and found that the specific activity of benzpyrene hydroxylase in the nonparenchymal liver cells was only 7.5% of the activity of that in parenchymal cells. This is much lower than the ratio of MFO activities in nonparenchymal to parenchymal cells obtained here (50%). We measured the disappearance of NADPH in the NADPH-dependent demethyl at ion of benzphetamine (7). The difference in these studies may be due to the use of different assay methods. Nevertheless both studies demonstrate that the nonparenchymal cells have less MFO activity than hepatocytes.
The subcellular fractions from nonhepatocytes were determined to contain 0.027 mg soluble protein per million cells, and 0.0063 mg microsomal protein per million cells; the subcellular fractions from hepatocytes contained 0.8 mg soluble protein per million cells and 0.29 mg microsomal protein per 10 cells. Thus, the enzyme activity expressed per million cells as shown In Table 3 was calculated from the specific activity previously shown In Table 2. The nonhepatocytes had approximately 1/450 GAST activity, 1/100 MFO based on cell number activity, 1/60 GEST activity, and 1/40 GR activity as compared to hepatocytes.
The total protein contents in nonhepatocytes and hepatocytes were determined to be 0.07 and 2 mg/per million cells respectively. The diameter of a nonhepatocyte Is 8-11u (3) and that of a hepatocyte is 18-30u (10). Assuming the cells are spheres, the volume ratio of a hepatocyte to a nonhepatocyte is the ratio of the diameters cubed, or close to 27. Thus, the ratio of the protein content in the hepatocytes to nonhepatocytes is within the range of the volume ratio of the two types of cells.
The distribution of enzyme activity liver (Table 4) can be calculated from the activity expressed per million cells (Table 3) and the cell number per gram tissue. In the rat, there are approximately 100x10 hepatocytes and 54X10 nonhepatocytes per gram liver (3,11). Thus, the nonhepatocytes had less than or equal to one hundredth the activities of MFO, GAST, GEST and GR as coopered to hepatocytes per gram liver. From this study. It is concluded that the nonhepatocytes have significantly less capability in the oxidation and glutathione-related detoxification of xenobiotlcs as compared to hepatocytes.
CMA 003356
ACKNOWLEDGMENTS
This work was supported by a grant from the Chemical Manufacturers Association.
REFERENCES
1. M.N. Berry and D.S. Friend, Jr. Cell Biol. 43, (1969).
2. O.M. Mills and 0. Zucker-Franklin, Am. Jr. Pathol. 54, 147 (1969).
3. D.L. Knook and E.C. Sleyster, Exp. Cel 1. Res. 99, 445 (1976).
4. R.N. Zahlten, H.K. Hagler, M.E. Nejtek, and C.J. Day, Gastroenterol. 75,
80 (1978).
--------------------
5. T.J.C. Van Berkel, J.K. Knight, R.G. Slee and J.F. Koster, Achives. Biochem. Biophys. 179, 1 (1977).
6. I. Carlberg and B. Mannervick, J^. Biol. Chem. 250, 5475 ( 1975).
7. A.Y.H. Lu, R. Kuntzman, S. West, M. Jacobson and A.H. Conney, J. Biol.
Chem. 247, 1729 (1972).
~ ------
8. O.H. Lowry, N.J. Rosenbrough, A.L. Farr and R.J. Randall, J. Biol. Chem.
193, 265 (1951).
" ------ ------
9. E. Cantrell and E. Bresnick, J^. Cell Biol. 52, 316 (1972)
10. Evaluation of Liver Function (Eds. S.O. Waife,; E.L. Platcow and C.E. Hammond) 2nd Ed. P. 11, Lilly Res. Lab, Indianapolis, IN (1974).
11. D.K. Knook, E.C. Sleyster and M.J. Van Noord, Jn^ Cell Impairment in Aging
and Development (Eds. V.J. Christofalo and E. Holekova). p. 155 Plenum Publishing Corp., New York (1975).
CMA 003357
7
Table 1. Determination of hepatocyte contamination in nonparenchyma1 cells of liver (pyruvate kinase activation method)
Tissue or Cell Type Nonparenchymal Cell Hepatocyte Whole Rat Liver
Activation of pyruvate kinase by addition of F-l 6-P2
TITis Lab
van Berkel and Koster
1.41 0.18 (3)
1.008 (18)
9.4 11.8 (2)
11.77 (19)
6.79 0.70 (4)
6.52 (22)
Table 2. Enzyme activities of various types of hepatic cells and tissues
Enzyme
GEST GAST GR MFQ
Fraction
SOL. SOL. SOL. MC
Specific actlivity (nmol/min/mg protein)
Nonhepatocyte
Hepatocyte
While Liver Tissue
42.9 18.5 47.4
7.49
17 (7) 6 (6) 2 (4)
2.3 (5)
82 11 (8) 275 61 (8)
65 7 (10) 16 5 (6)
74.1 (23)
213 (18) 50.3 (34) 12.6 (18)
CMA 003358
-4
8
Table 3. Enzyme activities of hepatocytes and nonhepatocytes
Enzyme GEST GAST GR MFO
Fraction SOL. SOL. SOL. MC
Activity (nmol/min/10 cells)
Nonhepatocytes Hepatocytes Hepatocytes/nonhepatocytes
1.16 65.6
56.6
0.5 250
440
1.28 0.048
52 4.4
40.6 96.7
Table 4. Distribution of enzymatic activity in various hepatic cells
Enzyme GEST GAST GR MFO
Fraction SOL. SOL. SOL. MC
Activity (nmol/min/g 1 iver)
Nonhepatocytes
Hepatocytes
63 0%)a
6,560 (99%)a
27 (0.1*)
22,000 (99.9%)
69 0.3%) 2.6 (0.6%)
5,200 (98.7%) 464 (99.4)
a: % activity in each cell type per amount of liver
CMA 003359
3
PREPRINT
PRELIMINARY ASSESSMENT OF THE USEFULNESS OF URINARY TOTAL GLYCOSAMINOGLYCAN
EXCRETION IN THE DETECTION OF SUBCLINICAL LIVER DISEASE
1
Charles E. Kupchella
Richard A. Greenberg
R.V. Warick
Carlo H. Tarrburro
Fran the Cancer Center and the Departments of Medicine and Corrunity Health
School of Medicine, University of Louisville Louisville, KY 40292
CMA 003360
1 Present Address: Department of Biological Sciences Mirray State University, Murray, Kentucky 42071
page 2
Summary
Urinary glycosaminoglycan excretion measured as uronic acid was studied in 60 asymptomatic vinyl monomer chemical workers. Thirty-six had normally and 24 had abnormally functioning livers as judged by a standard battery of biochemical liver tests. Urine samples were assayed for both creatinine and total cetylpyridinium chloride-precipitable uronic acid. Individual values were declared to be normal or abnormal based on the range 2.0 - 4.8 jig uronic acid/ mg creatinine established as the normal range at the outset. The frequency distribution of glycosaminoglycans for the groups of normal and abnormal biochemistries were statistically significantly different. The distributions did not differ in their means (t58=0.968), but did differ in their variability (F23 35=2.381; P<0.05). The observation that liver disease increases the range of value for total urinary glycosaminoglycan excretion, but not the mean, suggests that this parameter is not a useful general screening test in asymptomatic individuals with hepatic dysfunction. The increased variance in urinary glycosaminoglycan excretion in individuals with liver disease may reflect or be related to a stage of the disease process. At certain stages of disease, glycosaminoglycan incorporation (into scar tissue for example) may predominate while in other stages there may be a predominance of glycosaminoglycan-releasing, tissue destruction and/or an impairment of the liver's ability to clear glycosaminoglycans from the blood. These possibilities warrant further study with greater differentiation of disease categories and stages and with resolution of specific glycosaminoglycans patterns.
CMA 003361
page 3
INTRODUCTION
Changes in tissue/ urinary and blood glycosaminoglycans (GAGs)
have been found to occur in many connective tissue disorders including
those of the liver (Galambos and Shapira, 1973; Koizumi, et al. 1967;
Kojima, 1964; Rubin, 1966; and Patrick and Keenedy, 1964) and in
hepatic cancer (Kojima, et al1975f-^y*gfcfcileri, 1974; Kupchella, et al.,
1981; and Yamamoto and Teryama, 1973). In a previous report, we
described elevated urinary excretion of uronic acid in a number of
\
liver disease states (Kupchella and Tamburro, 1976) and showed that
angiosarcoma patients exhibit a urinary GAG excretion pattern distinguishe
from that of normal urine by relative increases in a hyaluronidase
resistant fraction and a decree** if* a hyaluronidase susceptible fraction
(Curran et al., 1977). The purpdse df' tltbr'study was to assess the
potential usefulness of total Urinary GAG- determinations in th
identification of liver disease amcrtg^dkamic*!-.
nomer) workers
other than hepatic angiosarcoma. MATERIALS AND METHODS
-w :5. , - ;w ^- v'- -*
-.i'.t'V... iM.
.-
One hundred non-biopsied workers (50 with and 50 without hepatic biochemical abnormalities) were selected at random from among more than 1200 vinyl chloride production workers at the Louisville plant of the B.F. Goodrich Company. Participation was voluntary and 36 workers without biochemical abnormalities and 24 workers with biochemical abnormalities elected to participate. Criteria used to determine the biochemical status of these workers' livers are summarized in Table 1.
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Urine specimens were collected during routine screening and frozen until analysis. Twenty-five ml. amounts were subjected to urinary GAG analysis in triplicate as described by DiPerrante (1967) and 5 ml. samples assayed for creatinine using a Technicon Autoanalyzer. Uronic acid determinations of cetylpyridiniumchloride complexed GAGs were made according to the modified carbozole method of Bitter and Muir (1962) and expressed as micrograms of uronic acid per mg of creatinine. Based on our work with normal controls (Kupchella and Tamburro, 1976) and reports by others (Varma, et al., 1974; DiFerrante and Rich, 1956) we defined the normal range of urinary GAG excretion as 2.0 to 4.8 ;ug of uronic acid per mg of creatinine, assuming that the normal adult male excretes 1.5 grams of creatinine every 24 hours (Sunderman and Boerner, 1940). Our definition of normal range was established in advance of the study from previous data on a "normal" cohort (640 adult males examined annually for 3-5 yrs). The data includes physical examination, liver spleen scan, SMAC 20, chest x-ray, 0.5 mg/kg dose ICG clearance, negative HBsAg serology, cbc and urine analysis. The GAG analysis was done blindly, i.e., clinical diagnosis of the patients from whom the urine was collected was not known.
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RESULTS
Sixty GAG determinations were made, 6 of 36 (16.7%) workers
with normal hepatic biochemistries had GAG excretions of less than 2 or ecual to or more cn*tn 4*8 ug uronie acid/mo creatinine* This
was true for ten of the groups of 24 (41.7%) workers whose bio
chemistries were abnormal. in Table 2.
The frequency distributions are given
DISCUSSION
We attempted here to assess the diagnostic, and other aspects of the minimally expensive, minimally time-consuming method of determining urinary GAGs. Because we found that the effect of liv r disease on urinary GAG was to increase variance without appreciably altering the mean, we have clearly not identified a new diagnostic test. These results suggest however that liver disease may impact on urinary GAG excretion in multiple ways. Subclinical hepatis dys function may favor uptake or incorporation of GAGs (fibrotic tissu for example) while other diseases or disease stages are dominated by GAG-releasing tissue destruction and/or the impairment of the liver's ability to clear the blood of circulatory GAGs.
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TABLE 1
Liver function tests used to determine "biochemical abnormality". Biochemical abnormality was established if two or more tests in group 1 were abnormal or if one from group 1 and two from group 2 were abnormal (negative otherwise).
GROUP 1
Alanine Amino Transferase (ALT)
GROUP 2
Gammag 1 utamy 1 Transpeptidase (GTP)
Indocyanine Green Clearance (ICA)
Bilirubin (total) (TB)
Alkaline Phosphatase (AP)
Aspartate amino transferase (AST)
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paga 7
TABLE 2
Frequency (f) and Relative Frequency (R.F.) of glyeosaoinoglycan excretion levels for workers with normal and abnormal biochemical results. A T-test of independent means (t58*0.968) revealed no significant difference, however an 7-test of the independence of variance (two-tailed) revealed significance (733,35*2.381} at the ?<0.05 level.
GACa <2
2<3 3 < 1* h<5
Normal . f R.F. U 0.111 16 O.Mtb 13 0.361 1 0.028
Abnormal f
R.F.
6 0.250
T_ 0.292
6 0.250
U 0.167
Sum Mean Variance
36 2.886 0.TU6
l.OOO.j, . ' -^.2k ,3.160 1.776
1.000
a jug uronic acid/mg creatinine "~
t
t
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i-diLt
0: 3 V>T.'
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