Document b590RkMR5xVznZ4z37G2GrLdg

/ r..-...r9 " ,+ m " 7 "r.n n ikj kftf *4i A ttlfeMi JM Jk ^ *k i* & *^1 * 7^ *"*y.** * n; i/r **** O**/ ^ ssai rcvr::s avcmie rrrTK:ii::;r;:ir ps.u\svlva.via nans t I t Report on: PROGRESS REPORT NO. 5 ON FIBROUS DUST STUDIES For: JOHNS-MANVI2-.LE CORPORATION PITTSBURGH CORNING CORPORATION PPG INDUSTRIES RAYBESTOS - MANHATT AN. INC. Date: June, 1909 i-Li234o~7 THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NUI (JUML'T^OM IT'S FILES AND CAN NOT'BE AUTHENTICATED BY PPG INDUSTRIES, INC. 5205 (412) 687-2100 UTMW*n ' INDUSTRIAL HYGIENE FOUNDATION OF AMERICA, INC. 5231 centre Avenue Pittsburgh. Pa. 13232 PROGRESS REPORT NO on 5 FIBROUS DUST STUDIES for * Johns-Manville Corporation PPG Industries Pittsburgh Corning Corporation Raybestos-Manhattan. Inc. i C. c ' Mn,V f by i ^ \J . U ;, L-. : ) . l . ; .' Paul Gross, M-D. Director, Research Laboratory Robert T. P. deTreville, M-D , D- Sc. _ President June, 1969 THIS DOCUMENT Rq^Rfrom 33 SdSoi be authent,gated . . , HVlfM iCTRtp1^. INC. j BB 00223^2_JL , 5208 s ! -s- > INTRODUCTION This investigation is divided into two parts: 1. The comparative pathogenicity of fibrous dusts in general 2. The determination of the locus of pathogenicity in asbestos dust The^study on the comparative pathogenicity of fibrous dusts has been completed. The purpose, the methodology, the results, and conclu* a ions of this study are summarized in the appended manuscript, "The Pul* ** monary Response to Fibrous Dusts of Diverse Compositions," which has been'submitted'for publication to the Journal of the American Industrial Hy giene Association. This work was presented at a symposium on fibrous dust on May 15, 1969, in Denver, Colorado, at the Annual Meeting of the AraerU can Industrial Hygiene Association. The second part, on the determination of the locus of pathogenicity in asbestos dust also has two parts: * 1. A study of the Inflammatory component m 2. A study of the oncogenic component THIS DOCUMENT WAS NOT. A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AN6 CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. 5207 * METHOD AND MATERIALS The working hypothesis, which forms the basis of Lhis investiga tion, is that the pathogenesis of asbestos does not reside in the asbestos mineral per sc. It is not the virgin ore which is the biologic irritant, but rather something (a hydrocarbon or a trace metal like nickel, chromium, or manganese) that is intimately associated with the mineral which may be responsible for the biologic effects observed. In order to test this hypothesis, each type of asbestos dust was treated in the following manner; a. heated in an eleetric muffle furnace considerably beyond the 'decomposition-point of any hypothetical hydrocarbon. b. immersed the different dusts in aqua regia to solubilize any trace metal present and subsequently treat with EDTA to remove the solu bilized metaL This was followed by copious washing. c. a combination of the two above treatments was used. The treat ment with aqua regia and subsequent EDTA was followed by heating to 950* C for two hours. For the purpose of determining the locus of the inflammatory com- % ponent on asbestos dust, the period of observation of the test animals was set at 12 months because by this time inflammations caused by these dusts were generally healed. All surviving animals were, therefore, killed at the end of 12 months following the intratracheal Injections. However, s me ani mals were also killed at the six-month period from eaeh group for the purpos of sampling. THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES. AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. | BB 0022343 | 3. The animals injected for the stud/ of the oneogenic factor in as* bestos dust have not been sampled. The/ arc being allowed to live out their lives. The experimental protocol is given in tabular form in Tables 1 fc 2. The intrapleural injections (Table 2) are for the purpose of using Wagnur's criterion of oncogenesis, namel/, the production of mesotheliomas as an indicator of the oncogenic potential of the various asbestos dusts and their modifications. It is to be noted that of a total of 766 rats, 235 were used for the in flammatory component and 481 for the oncogenic aspeet. Of the 481 animals used for the study of the oncogenic aspect of the problem. 293 were injected intratracheally and 194 are still alive; whereas, 188 were injected iatrapleurally, and 169 of these are still alive. RESULTS A. Inflammatory Component. During the 12 months of observation* there were many deaths from interenrrent pneumonia. The highest mortality was 48?* and the low est, 16%. It is doubtful that this mortality bears any relation to the nature t of the dust in the lungs. Regardless of the manner in which the dusts were --modified, all dusts-pxoxed capable of causing destruction of alveolar tissue. o that dense collagenous sears were produced. There is, at present, no discernible difference in the' number, size, or character of the scars produced THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. | BB0022349 | 5203 ^ f**, ** j 4 a - } 4. by ihe different modifications of asbestos dust nor in their location. 1 liey are generally situated in the region of a terminal or respiratory bronchiole. B. Oncogenic Component No pulmonary or pleural tumor has, as yet.been observed among the animals on test. summary Neither heating any of the three most common types of asbestos to a .high temperature (above the decomposition point of hydrocarbons) nor treat- ment with strong acid (aqua regia) followed by a sequestering agent (EDTA) resulted in detectable amelioration of the inflammatory response evoked by these modified asbestos dusts. Inasmuch as the intratracheal technique of introducing dust inu he lungs produces lesions not encountered when the same dust is inhaled (see attached manuscript), interpretation of the results here obtained is difficult and is best made with reservations. It is advisable to repeat this study and impose the lung dust burden by the inhalation method. Insufficient time has elapsed to allow conclusions regarding the on cogenic potential of these dusts. B_00 22345~7 THISvDOCUMENT was not a record of PPG INDUSTRIES, INC. DIB NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. 5210 mjl t. in:.> NOT ^v:u J:i ` \ * \* TABLE 1 5. Tabulation of Groups of Rats Injected Intratracheal]/ with Processed Asbestos Dual Material How Processed Dose No. Death in Mus. Nuw me. Rats 5 ... 12__ Livinu Amo site Chxysotile Crocidolite V* * -- Hammermi11 e d Heated to 1050" F (one hour) Aqua Regia, then EDTA Extracted with Solvents Hammermilled Heated to 1000" C (two hours) Heated to 1100* F (10 hours) Aqua Regia,then EDTA Hammermilled Heated to 1050* F (one hour) Aqua Regia, then EDTA Extracted with Solvents Hammermilled Heated to 900* C (two hours) Aqua Regia, then EDTA Free of Metal Contact Hamme rmilled Heated to 1050' F . (one hour) Aqua Regia, then EDTA Extracted with Solvents Hammermilled Heated to 1100* F (10 hours) Heated to 950* C (two hours) Aqua Regia, then EDTA -Aqua Regia + EDTA + 950* C (two hours) 3.5 3.5 3.5 3.5 21 1.75 3.5 1.75 3.5 3.5 3.5 3.5 1.75 3.5 1.75 3.5 3.5 3.5 3.5 3.5 21 10.5 1.75 1.75 ., . 1.75 23 24 25 20 21 20 21 27 181 24 27 27 24 31 20 20 20 193 22 25 24 20 21 21 20 31 20 204 3 4 6 7 .6 -- 11 -- 2 7 8 4 -- -- -- -- 6 5 4 2 8 4 3 -- -- 50 4C 7 fc 90 -- 15 -- 17 --8 -- 10 50 50 c8 c 13 40 -- 16 ' -- -- -- 8 17 11 20 64 C 6C 6C 3C -- 10 -- 17 -- 17 -- 16 a h--^ . * -- -- i8s0 AS (The first four items under each type of asbestos involve groups of rats concerned wiLh the study of the inflammatory component. /; s /* The other Items represent groups of rats concerned with the study f the oncogenic component) 521A THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. Material Amo site Chrysotile Croeidolite 6 TABLE 2 Tabulation of Groups of Rata Injected Intraolcurally with Processed Asbestos D'ist How Processt ed Hammermilled Heated to 1000* C (two hours) * Aqua Regia, then EDTA Free of Metal Contact Heated to 900* C (two hours) HammermiUed Heated to 950* C (two hours) Aqua Regia, then EDTA Aqua Regia + EDTA + 950* C (two hours) Dose m?. 50 50 50 50 50 5G 50 50 * 50 No. Death in Mi-. Now Rats 6 1 2 Living 23 22 * 20 20 20 -- -- - 11 20 -- -- 19 * 24 -- 20 -- -- 19 -- 19 20 -- -- 21 -- -- 20 -- -- 183 20 19 20 16V (Those animals chat have died before the six-memth period are not listed l& the tabulation) NO.-TT-?--* r' 15 .*; ! * <t V MOT CoiVi^i ruu = :i | BB 0022347 | . TPHPGISINDDOUCSUTMREIENST, INWCA.SDINDONTOAT CROECMOERFDROOMF IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. i1 erp-e *> *+*-*5 APPENDIX 1 W12.' 687 2100 INDUSTRIAL HYGIENE FOUNDATION OF AMERICA. INC. 5231 CENTRE AVENUE PITTSBURGH. PA. 15232 THE PULMONARY RESPONSE TO FIBROUS DUSTS OF DIVERSE COMPOSITIONS* by *I Paul Gross, M. D. Z Robert T. P. deTreville, M. D., D. Sc. Lewis J. CrAlley, Ph. D.^ William T. Cranquist, Ph. D.4 * Fred L. Fundsack, Ph. D. NOTE: T' ^ _ NOT CCiViL r riUivi i' " f'.'n rr [\ j, ri--- w rSSSfa ,rSnN0T A RC0RD OF IT'S files And cannot rf a?.T C0me from BY PPG INDUSTRIES,%c, ENT,CATEO -filT0022343^^ 1. Director, Industrial Hygiene Research Unit, Department of Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pa. IS 2. President, Industrial Hygiene Foundation, 5231 Centre Avenue, Pittsburgh. Pa. 15232 . 3. Scientist Director, Director of Epidemiology and Field Studies, Occupational Health Program, National Center for Urban and Industrial Health, Public Health Service, 1014 Broadway, Cincinnati, Ohio 45202 4. Senior Fellow, Mellon "institute, 4400 Fifth Avenue, Pittsburgh, Pa. 15213 5* Vice President for Research and Development. Johns-Manville Research and Engineering Center, Manville, New Jersey 08835 5213 Paper presented before AIHA Conference, Denver, Col rado, May 15, 1969* T! T3" r "5"1 3 ' (' NOT L,- j*, ... 1 : v_`:.: ; . : ABSTRACT fibrous quartz, ehrysotile asbestos, and tremolite talc dust, all of respirable particle size, injected iatratracheally, produced polypoid pro liferative inflammations within smaller air conducting tubes as well as more peripherally. With time, the inflammatory tissue became converted into collagenous scars which often caused permanent deformities of bronchi and bronchioles. Following intratracheal injections of such fibrous dusts as synthetic ehrysotile, ecramie aluminum silicate, silicon carbide, glass, or brucitc, ^ the main pulmonary response was a macrophage reaction with minimal stromal participation. Xn addition, within four days after the injection, there were foci of polypoid proliferative inflammation but limited to the more peripheral respiratory bronchiole and alveolar duets. Because these polypoid lesions did not collagenize, did not destroy the anatomic integrity of the air spaces, and because the lesions were reversible, the dusts calling forth this type ~ot response must be classed as biologically "inert." Furthermore, the .polypoid lesions are believed to be artefactual in the sense that their pr due*ion is determined by the method of introducing the dust into the lungs since su*.h lesions are not seen in animals in inhaling high concentrations of the same dusts. THIS DOCUMENT WAS NOT A' RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES. AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. ST 00223M-! 5214 NOTE: ' NOT : ' ........ With the increasing production and use of fibrous materials, both th naturally occurring and that industrially produced, the dust created by thuir fragmentation is becoming more prevalent. We know that one type of na turally occurring fibrous dust, namely asbestos, is biologically active and is capable of causing extensive and fatal scarring of the lungs and some kinds of this mineral have been associated with the production of cancer. e Inasmuch as it is not known exactly what it is about the asbestos dust particle that is responsible for its pathogenicity, the simplest explanation which seemed to be attractive to many in thepast was that the pathogenicity of * asbestos and, therefore, also of all fibrous dusts,was related to the fibrous shape of the particles. According to this theory, when the fibers are inhaled, their sharp ends traumatize the cells which they contact and fibrosis results from the multiple traumata. Although some years ago we had investigated the pulmonary response to one industrially produced fibrous dust, namely ceramic aluminum silicate fibers and found it to, be biologically "inert, in recent years the necdlc-like - ,character of fibrous dust has again been implicated as the pathogenic factor. This has occurred in connection with fibrous glass dust; the pathogenic -po tential of which has been questioned in spite of the fact that nonflbrous glass dust has been found to be biologically "Inert. This paper is concerned with a study of the pathogenic potential of fibrous dusts not heretofore documented and with the pathologic effects of these, as THIS'DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES Artb CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. L>- 5215 NOTE: th:: ' NOT C0:v;2: a v,' ; ? J .- j 2 well as, of previously investigated dusts that have not been reported. This study is part of a more basic investigation being conducted in cooperation with the U. S. Public Health Service and industry,* the purpose of which is to determine the locus of pathogenicity of asbestos dust. METHODS AND MATERIALS A tabular summary of the types of dust studied, the number of rats employed, and the dose of dust administered, is given is Table 1, Included under any one type of dust may be two or more materials from different * sources of slightly different compositions but grouped together because, for the purpose of this study, no significant difference was noted. For instance, micro quarts prepared at the Johns-Manville Research and Engineering Center consisted of resintered, acid-leached glass fibers with an originally high alkali content. The average diameter of the fiber was 1.2 p. Two batches had been prepared: one with a metallic nickel c ntent of 0.11% and the other, of 3.1%. The natural ehrysottle was also of two kinds; one had been ball milled and then hammer milled. In the latter process, besides being reduced to submicronic dimensions, it also acquired an increased nickel content from the nickel-steel alloy of the hammers. The other was comminuted by ball milling only. * Grant Number 1 &01 UI-00849-01, U. S. Public Health Sorviee (Asbestos Dusts, Their Pathogenic Components). THIS document was not a record of PPG INDUSTRIES, INC. DID NOT*COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. 1 BB 0022351 5216 3. The talc dust was of the trcmolUc variety and there were two kinds: one had a high natural nickel content and contained fibers with an average diameter of 0. 2 p; and the other, a low nickel content and contained fibers with an average diameter of 0.1 p. Two batches of synthetic chrysotile were employed. One, prepared at the Mellon Institute, Pittsburgh. Pennsylvania, had a purity of about 90%. The impurities consisted largely of bruclte (MgfOH)^). The diameter of the tubular crystals averaged 0.02 p and their length varied from 0.C8 to 0. 17 p The other batch was synthesized at the Johns-Manville Research and Zngi- e neering Center, Manville, New Jersey. Its purity was 99.4%. The average diameter of the crystals was 0. 03 to 0. 04 p with a length of 1 ^ or less, al* though a few fibers were up to 5 p in length. Both lots gave X-ray diffraction patterns typical of chrysotile (Fig. 1). Five different varieties of fibrous glass were injected into rats. These averaged about 1 ^ Is diameter. One was etched, two were uncoated, one was coated with a textile-type of binder (mostly starch), and the last was * coated with a phenol-formaldehyde resin type binder (used largely for insulation). The ceramic aluminum silicate fibers (Flberfrax from Carborundum Company) had an average diameter of 2.0 p. Two batches were used: ne had been hammer milled to increase its nickel content; and the other was briefly comminuted in a glaap, tissue grinder. The silicon carbide whisk rs, also obtained from the Carborundum Company, had a fiber diameter ranging b,*w," m`Sfcb?!F'e'*n 100 *Bd 750 ** PPG INDUSTRIES, INC. DID,NOT COME FROM IT'S FILES. AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. ] BB 0022352 5217 1 r.r-1"' ^ NOi Co.-'4-'1,1 > . * - 4. Amorphous magnesium silicate was used as a nonfibrous control dust. It was prepared by reacting a solution of magnesium chloride with a solution of sodium silicate. The resulting precipitate was washed with abundant water and a standard Suspension was prepared. All dusts were suspended in water, the concentrations depending on the amount suspended in 1 ml water which could be injected without killing the rats. Most suspensions contained 3.*5 mg dust per ml. Several sus pensions contained 25 mg dust per ml. A total of 424 rats were injected intratracheal!y with these dusts. In some groups the total dose was administered by as many as four in jections. The injections were made under light ether anesthesia with the aid of an Illuminated laryngeal speculum that allowed the introduction of a spinal-type needle between the vocal chords under direct observation. In order to study the early pulmonary response to the various types of dust, four rats were killed from each group four days after the first intra tracheal dust injection. The rest were allowed to live out their lives. The ** lungs of all animals were distended with 47* formaldehyde solution under a * head of 10 to 12 cm water. Paraffin sections of the lungs were stained routinely with hematoxylin and eosin. Pertinent fields were photographed and after impregnation with silver, the same fields were rephotographed in order to study the relationship between cells and stroma. In order to study the re lationship of the dust to the Jesions, some sections, cleared unstained, were ."OT RLES WD CANNOT BE AUTHENTICATED j~BB 00 22353__[ 5218 r- -r\ r . NOT CO'.'Vc v ' - 5. examined or photographed under dark-field Illumination;'other sections were subjected to microincineration and were similarly examined or photographed under dark-field illumination. RESULTS Four days after the intratracheal injection, the lungs burdened with asbestos, talc, and mieroquartz showed a proliferative inflammation ine volving widely scattered smaller bronchi and bronchioles. This was char acterized by polypoid processes of avaseular fibroblastic tissue rich in argyrophilie fibers which enmeshed large amounts of the injected dust. These polypoid structures originated from one or several widely separated ulcers in the mucosa and distorted the bronchial lumen, converting it into disconnected circumferential channels that tended to encircle the central stromal plug. These channels quickly became invested with normal appearing ciliated columnar epithelium. Within a few months, the argyrophilie fibers were replaced by dense collagenous tissue. The lungs Injected with asbestos dust had, in addition to the pr Ilf rative Inflammation In the smaller bronchi and bronchioles, similar lesions in the res- *e * piratory bronchioles and alveolar ducts. These more peripheral polypoid struc tures originated from one or more of the evaglnating alveoli. Although th f r- mec. didnot-become. covered, with epithelium, as happened In the terminal bron- chioles and larger passages, they did become converted into dense collagen and as a result, underwent considerable shrinkage (Fig- 2). THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT*COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. 5219 The lung* injected with talc showed.numerous foci of proliferative Inflammation in respiratory bronchioles and alveolar ducts similar to those encountered in lungs injected with asbestos (Fig. 2); and like the latter, considerable shrinkage of the lesions occurred months laier when the ini tially argyrophilic stroma became converted into dense collagen. The main pulmonary response to the dusts of synthetic chrysotile, eer. amic aluminum silicate fibers, fibrous glass, brucite, and silicon carbide whiskers was the mobilization of macrophages which, filled with dust, occupied alveoli evaginating off respiratory bronchioles and alveolar ducts along with * much extracellular dust. The walls of these alveoli were thickened by a com bination of surface cell enlargement and arborescence of the septal argyrophllie stroma. Perhaps the most interesting feature of the pulmonary response was the development of fibroblastic tissue processes from one or several of the evaginating alveoli of respiratory bronchioles and alveolar duets. This fibro blastic tissue, supported by argyrophilic stroma, extended in a polypoid manner into the lumen of the parent structure (Fig. 3). Well developed by the f urth post-injection day, these lesions were less numerous by the fourteenth day and could not be found six months and longer after the Injection. Collagenisation I of these lesions was not observed at any time. Evidence of the dust Injections was still present (n the form of dust-laden macrophages scattered throughout the section, but these were less numerous, loose, and usually separated from one another, and the walls of the air spaces In which they were found now were thin THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID (\10T COME FROM IT'S FltES AND CANNOT BE AUTHENTICATED BY" PPG INDUSTRIES, INC. 5220 NOT NOT %*/ i / ' 7. and delicate. Along with the disappearance of the intraluminal polypoid * inflammatory tissue and the reduction in macrophages, the amount of dust in the sections appeared to undergo a parallel reduction. The lungs of rats injected with amorphous magnesium silicate also showed occasional proliferative polypoid fibroblastic inflammation in respiratory bronchioles and alveolar ducts and, like the lesions associated with synthetic chrysotlle injections, they were no longer found some months later. In the main, the pulmonary response was a macrophage reaction with minimal stromal reaction. Giant cells were also prominent. COMMENTS According to the commonly accepted definition of a fiber, a particle whose lengt? is three times its diameter or longer, synthetic chrysotilc certainly is fibrous. In one batch (Mellon Institute), the individual partieles when viewed under an electron microscope, are tubular crystals, the dia meter of which in relation to their length Is such that by no stretch of the imagination can they be considered nee dle-like (Fig. 1A). * Nevertheless, this material, injected intratracheally. has produced proliferative inflammatory lesions similar to those produced by injected brucite. Furthermore, iden tical lesions have been seen in an occasional animal Injected with amorphous magnesium silicate. It, therefore,, appears that the proliferative inflamma- tion noted four days after synthetic chrysotlle injections may be aseribed to the high local concentrationsnf magnesium silicate associated with the intratracheal Injections. * V THIS DOCUMENT WAS NOf A RECORD OF PPG INDUSTRIES. INC'. DID NOT COME FROM IT'S FILES AND CANNO T BE AUTHENTICATED BY PPG INDUSTRIES, INC. "flF0022356TM 5221 V* V- .J In view of the proven biologic Inertness of ceramic aluminum silicate:. ^ silicon carbide. and of glass, (*) it is difficult to explain the production of the proliferative inflammation observed following intratracheal injectiou'nf the needle-like particles on any other basis than that of mechanical trauma. It would seem that the injection under pressure from the syringe causes the fluid to emerge from the needle with high velocity. .Also, the fibrous particles, tending to align themselves parallel to the stream would thereby tend to impinge point first on the mucosa of branching conducting tubes and the possibility of multiple small traumata, amounting to abrasions, becomes a probability. Nevertheless, we are faced with apparent contradictions. When we' first Investigated the biologic potential of ceramic aluminum silicate fibers, ^ we did not observe the proliferative inflammatory lesions described above. The reason for this failure lies in the fact that these lesions disappear with . time and we had not examined the lungs during the first two we^ks after the intratracheal injection. Another highly significant contradiction lies in the fact that such polypoid intraluminal proliferative lesions as arc found following the intratraeheal in jection of certain fibrous dusts are not encountered when the same dusts are inhaled, even in high concentrations. Examples of this contradiction are chrysotile asbestos and fibrous glass. Animals have been exposed to high concen trations of chrysotile asbestos dust In Inhalation chambers for more than a year without such polypoid-proliferative lesions having been observed. ^ We have e THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES. AND CANNOT BE AUTHENXJCAf ED BY PPG INDUSTRIES, INC. . j'TbT022357_ 5222 \J v) ; *1 w .IW i t 9. under study at the present time rats and hamsters that have inhaled coated * and uncoated fibrous glass in concentrations approximating 100 mj/m^ for over one year without detecting any such proliferative lesions W (Fig 4). We are, therefore, forced to conclude that fibrous dust, when in jected intratracheally under pressure, may produce mechanical trauma resulting in inflammatory foci which, however* resolve and disappear with time; these lesions must be considered artefactual. The difference between the proliferative lesions produced by the intratracheal injection of fibrous quarts, asbestos, and talc on the one hand e and those produced by similar injections of synthetic chrysotilc, silicon carbide whiskers, fibrous ceramic aluminum silicate, fibrous glass, and brucite on the other hand is the difference between the deformed bronchi and bronchioles caused by permanent scars and short-lived reversible lesions e Viewed from another angle, the proliferative lesions produced by all the fibrous dusts investigated except those of quartz, asbestos, and tale have the following characteristics: * 1. significant collagenization in the reacting lung tissue is absent 2. the anatomic integrity of the air spaces is maintained in spite * of the presence of dust therein 3. the lesions are reversible __ I BB 0022358*7 These features are those of biologically "Inert" dusts^) end justify * classifying synthetic chrysotile, fibrous glass, brucite. silicon carbide THIS DOCUMENT WAS NOT A RECORD .OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. . 5223 10. whisker*, and ceramic aluminum silicate in this category in spite of the polypoid proliferative inflammation produced when these dusts are injected intratracheally. The proliferative inflammation is considered to be artefactual, dependent upon the injection technique. Vr-,' i '.U < i. -j" j > *. THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. | BB 0022359 | 5224 REFERENCES X. Gross, F., Wes trick, M. L.. Schrcnk, H. H., and McNerney, J. M: The Effects of a Synthetic Ceramic Fiber Dust upon the Lungs of Itais, AMA Arch. Ind. Health 13:161 (1956). 2. Gross, P.t Wes trick, M. I... and McNerney, 7 M.: Glass Dust. A Study of its Biologie Effects, AMA Arch. Ind. Health Zl^: 10 (I960). 3. Gardner, L. U.: Studies on the Relation of Mineral Dusts to Tuberculosis, m The Relatively Early Lesions ih Experimental Pneumoconiosis Pro* dueed by Carborundum Inhalation and their Influence on Pulmonary Tuberculosis Am. Rev. Tuberc. * *7*:344, (1923). 4. Gross, P., Westrick, M. L., and McNerney, J. M.: Experimental ** Tuberculopneumoconiosis, AMA Arch. 2nd, Health 19:320, (1959). 5. Wagner, J. C.: Asbestosis in Experimental Animals, Brit. J. Ind. Med. 20:1.(1963). * 6. Gross, F., deTreville, R. T. P.. Tolker, E. B., Kasehak, M., and Babyak, M. A.: Experimental Asbestosis, The Development of Lung Cancer in Rats with Pulmonary Deposits of Chrysotile Asbestos Dust. Arch. Environ. Health ,15:343, (1967). * 7. Gross, P.. deTreville, R. T. P., Tolker, E. B., Kasehak, M.. and Babyak, M. A.: Fibrous Glass Dust, The Pulmonary Response to Long-Term Inhalation of High Concentrations, to be published. 8. Gross, F. and Nau, C. A.: Lignite and the Derived Steam-Activated Carbon. The Pulmonary Response to Their Dusts, Arch. Environ. Health _14:4$0. ( -L. 0022360 THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES. AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. 5225 4 RECORD OF ssgSSs N. 3 ! - Table 1 V r't'' Iw gftSS**9- 'NC- Tabular Protocol of Rats . Injected Intratracheally with Dusts Dust Microquartz (a) Natural Chrysotile (b) Talc (tremolite) (c) Synthetic Chrysotile (d) Ceramic Aluminum .. Silicate (e) Glass (fj Bracite Silicon Carbide (g) Amorphous Magnesium Silicate (h) N O 1 o Fiber Diameter (microns) No. Rats Dose Mortality (i) 1.2 62 25 mg 26% in 6 months 45% in 15 months 0. 05-0.2 0.2-1 55 10. 5 mg + 14 mg 90% in 18 months 100% in 24 months 9 50 ` 25 mg 40% in 6 months 44% in 6 months 0. 02 - 0.04 55 2.0 80 14 mg 4 45 mg 10;5 mg 22% in 12 months 53% in 24 months 72% in 18 months 85% in 18 months 1 75 10.5 mg 67% in 12 months 100% in 18 months 2-3 15 10.5 mg 47% in 12 months 73% in 24 months 0.5. - 3.0 22 3.5 mg 18 rats sacrificed at intervals (no deaths in 6 months) 10 75 mg 10% in 6 months | BB 0022361 | a. High nickel. 35 rats; medium nickel, 31 rats; and idw~Uicicely "'7 rats b. Ball-milled dust given to 40 rats and hammer-milled dust to 15 rats c. Talc with high and low natural nickel content (given to 25 rats each) d. One batch prepared at Mollon jnstitute; "the other -at Johns -Minwille--------- Research and Engineering Center e. Named Flberfrax, obtained from Carborundum Company f. Groups of 15 rats givei\ different kinds of fibrous glass; 1, etched glass; 2, uncoated; 1, coated with starch binder; 1, coated with ^_ resin t j OZ* g. Silicon carbid whiskers from'Carborundum Company h. Prepared by reacting sodium silicate with MgClj and washing precipitate l. Range /mortality in months of different groups il . V 3 ' ' 3 Lr. i 1 i LEGENDS OF ILLUSTRATIONS i( Fig. 1A Tubular crystals of synthetic chrysotile prepared at Mellon * Institute. Pittsburgh, Pennsylvania. Pig. IB Crystals of synthetic chrysotile prepared at the Johns-Manvvlle Research end Engineering Center, Manville, New Jersey. Note that these crystals are longer and needle-like; also, that the magnification is approximately 1/10 of that in Pig. 1A. Pig. 2A Contracted, densely collagenous scar in lung of rat injected latratracheally with 3. 5 mg very finely comminuted ehrysotile * , 23 months previously. The scar probably represents an ob literated bronchiole as judged by the size of associated blood vessels on Its right border, Homatoxylia and eoson. X 150 Pig. 2B Acid-insoluble ash pattern superimposed upon the same field as la Pig. 2A. It shows three dense deposits of chrysotile dust la what probably was originally the lumen of the bronchiole. The "snow" in the background iz artefactual. Micro incineration. X 150 "",^''qq*22362_^ e Pig. 3A A polypoid fhVsl of Inflammatory tiesuo-eeoopias-the 1nmin of a respiratory bronchiole. Scattered macrophages are seen In . THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. ~ 5227 i rx - * '' ^ r. ' I 'j ij I \i i i I i-- * I i ^ * t ` '. LEGENDS OF ILLUSTRATIONS (continued) Fig. 3A many alveoli. Rat injected intratracheally with 3.5 mg ceramic aluminum silicate and killed 4 days later. Hematoxylin and eosla. X 150 Fig. 3B Polypoid masses of inflammatory tissue occupying the lumen of a respiratory bronchiole (middle left) and the lumen of an alveolar duet (lower right), respectively. The inflammatory tissue is loose and cellular. Transparent fibers and a giant cell are seen in the polyp in the lower right portion of the field. Rat injected intratracheally with 3. 5 mg glass fibers and killed 4 days * later. Hematoxylin and eosin. X 150 Fig. 3C A terminal bronchiole containing a polypoid mass of inflammatory tissue enclosing numerous opaque fibers. It is of interest that the inflammatory tissue is already (96 hours) covered by bron- chiolar epithelium. Numerous leukocytes are present. Rat in jected intra* tracheally with 3.5 mg silicon carbide whiskers'and killed 4 days later. Hematoxylin and eosin. X 300 1 bs"0022363 j Fig. 4A This field Is typical of findings in the lungs of rats that had inhaled "*~flbroas glass dust (100 mgfm?) for 232 days, 6 hours per day. * It is to be noted that there is no fibrosis. The alveolar walls are thin and delicate but small clusters of darkly staining alveolar THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY' PPG INDUSTRIES, INC. 5223- 1 j' LEGENDS OE ILLUSTRATIONS (e nlinucd) Fig. 4A macrophages are present in alveoli clustered about some alveolar ducts. Hematoxylin and eosin. .X 150 Fig. 4B The same field as In Fig. 4A after deeoloriaation and silver impregnation showing minimal stromal reaction.which is limited to the regions where macrophages are clustered and consists of arborescent retiehlin fibers. Gordon and Sweets. X 150 Fig. 4C This la the acid-insoluble ash pattern superimposed up-'r. **-e same photograph as in Fig. 4A. The large amount of fibrous glass dtfst demonstrable and the insignificant tissue reaction to its presence point to the biologic "inertness" of this fibrous dust. The "snow" in the background is artefactual. Microincineration. X 150 1 BB 0022364 | THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOTBE AUTHENTICATED 1 BY PPG INDUSTRIES, INC.