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VOLUME 30, NUMBER I January-February, 1949 j- 0 UNIVERSITY OF TEXAS American Industrial Hygiene Association Journal American Industrial Hyg'^ne Conference Denver Hilton, Denver, Colorado May 12-16, 1969 January-February, /yijgl N 0. 0^ ate of 415 kg-m/minute, would pi0. positive pressure inside the face mask times at this work rate, and would ; a protection factor of at least 1,000,' Chronic Toxic Effects of Polyphenyl Mixtures vledgments GERARD YOUNG, M.B., Ch.B., C.R.C.P.(C.)*, A. PETKAU, M.Sc., M.D**, and authors gratefully acknowledge the> al assistance of Mr. William Hindj irried out the mask pressure studies Floyd Hardwick who conducted thq or leakage tests. ices MA*> W* A- Burgess: A Self-Contained r329UI(?%4)l ter Respirator* Amer\ lnd- XyS- 'W 'oo,R. J., and 0. M. S. Greenhalgh: A SH*. ined Pressurized Blouse. Ann. Occup. Hyg. 8: 24 ss, W. A., and W. Nettle-ton : An Improved Air. ^Respirator, AMA Arch. Environ. Health 16: J. HOOGSTRATEN, M.D., Ph.D.t Children's Hospital, Winnipeg 3, Manitoba, Canada At a daily dietary intake of 350 mg/kg or more, Santowax OM, a mixture of v terphenyls used as a coolant, causes severe and to some extent irreversible chemical nephrosis and interstitial nephritis in rats following prolonged ingestion. * At a daily dietary intake of 33 mg/kg or more, an O.M.R.E. High Boiler sample, consisting of terphenyl and radiolytic and pyrolytic products thereof, induces a marked reticuloendothelial hyperplasia in rats following lengthy oral administration. , This process is most marked in the liver and leads to an irreversible monolobular - cirrhosis. A., B. G. Fuuus, Jr., and M. N. Rao: Oxygen. Zhhlt 96`(1959)" JU,e WrkerS- AMA Ani l, F. D. K.: Estimation of Energy Expenditure Expired Air. J. Appl. Physiol. 18: 25 (1963;. Introduction phenyl mixture used as a moderator and , S.: Personal communication. NN, G.: Physiological Measure_ments a.s Basis _ rk Organization in Industry. Ergonomics 1: 328s pERTAIN POLYPHENYL COM POUNDS have been used as moderator tfANN, L., R. C. Lee. G. Lee, K. R. Drinker M. Carpenter: Fundamental Factors in the !)$ 1 Protective Respiratory Equipment: Inspiratory Measurements on Human Subjects With and t Resistance, ORSD Ript. No. 1222 (1943). M, R. F.: A Method for Evaluating the Protec lorded When Wearing A Respirator. UKAEA Re Group Rept. AERE-R-4125, Health Phys. Di\ , Energy Research Establishment, Harwell, Berk* 1962). Received July 30, 1968 Coolant in nuclear reactors for some years and some information has been gathered on the acute oral and inhalation toxicity of these compounds.1'2'3'4 A recent investiga tion has indicated that prolonged ingestion of polvphenyl mixtures causes significant renal disease in experimental rats.5 The. gune experiment has indicated that ingestion epartment of Health, EducaA Review and Analysis of Iforth, and G. J. Wold. AIi These are primarily losses hich have been analyzed by eau of Radiological Health, ication may be obtained in 6f the pyrolytic and radiolytic products of these polyphenyl compounds over a period Of time gives rise to severe hepatic cirrhosis. paper reports a more detailed exam;:lvutiion1 of the histopathology ensuing upon ri'jfljsistion of Santowax OM and an O.M.R.E. Boiler sample. >n and Education, Environ : Parkway, Rockville, Mary- and Materials coolant in the Organic Moderator Reactor Experiment (O.M.R.E.) reactor at the Na tional Reactor Testing Station (N.R.T.S.), Idaho Falls, Idaho and had been withdrawn from the reactor on October 9, 1961 having been irradiated for 152.7 megawatt days. The radioactive components were Co60, Mn", and Cs137 in a concentration of less than 10`5 /ici/gm of the sample. In mixing the High Boiler sample with rat chow, a dilution factor of 20 or greater was intro duced. The concentrations of the isotopes in the made-up diets were therefore at least several orders of magnitude below the maxi mum permissible concentrations in water, (MPC)W, given for these radionuclides in Table I of ICRP Publication 2.6 Chemically this sample was composed almost completely of polyphenyls, triphenylenes and phenanthrenes together with alkylation, phenylation Santowax OM is a commercial organic and hydrogenation products of these three ch Coolant manufactured by the Monsanto types of aromatic compounds.7 The com the publication of a new trum of safety research. Dr. arch Department, will edit >n will contain in-depth inerest to persons from such at, education, law and med;arch Department, National Chfcmir.d Corporation. The O.M.R.E. High Boiler sample was an extract of th^-poly- , *AwttUrU Pathologist, Children', Hospital, Winnipeg,- Man- Itobft, Canada. Jn*>s reprint requests to Dr. A. Petkau, Medical Bio Section, Whitesnell Nuclear Research Establishment, Energy of Canada Limited, Pinawa, Manitoba, positions of the mixtures used in this study are detailed in Table I. Two month old black hooded rats were used in the experiment and were fed on Purina rat chow. The rats were divided into eight groups, each containing nine male and licago, Illinois 60611. The 001 ate Professor of Pathology, University of Manitoba nine female rats with the exception of the of Medicine, and Head, Pathology Department, ChilHospital, Winnipeg, Manitoba, Canada. first group 7 (Group A) which was composed 8 January-February, 1969 of five male and six female rats. Groups A and B were control groups. Group A was fed chow pellets only and Group B was fed chow pellets and com oil, equivalent to that consumed by the remaining groups. The composition of the diets together with the daily amount of polyphenyl ingested by the rats are outlined in Table II. Groups C, D and E were fed the diet B with the addition of 0.01, 0.1 and 1.0% by weight of Santowax OM, respectively. Groups F, G and H were fed diet B with the addition of 0.1, 1.0, and 5.0% by weight of O.M.R.E. sample, respectively. Three rats of each sex from the test groups were sacrificed on the 130th, 188th and 235th days, with the ex ception that the last three males and three females on diet E were put back on diet A from the 189th day until their sacrifice on the 235th day. This was done in order to assess the degree of reversibility, if any, of the renal lesions already discovered in the test groups previously sacrificed. The brain, stomach, gastro-intestinal tract, mesentery, liver, spleen, heart, lung, kidney, urinary bladder, testis or ovary, and bone marrow were obtained for microscopic examination. Results Santowax OM In general, Santowax OM inhibits weight gain and leads to anemia, and these findings together with the results of a paired feed ing experiment have already been published by Petkau and Hoogstraten.5 Other morpho logical changes involved the kidneys and livers of test groups. Renal disease was Table I* j Composition of the Polyphenyl Mixtures A ---------- - Nonirradiated Weight Mixture % Irradiated Mixture Weigh Santowa^OM: Biphenyl o-Terphenyl m-Tfrphenyl p-Terphenyl 4.7 OMRE High Boilers: High Boilers > 98 64.1 Biphenyl <<0o,1il25.1 o-Terphenyl <o|6.1 m-Terphenyl <o,ap-Terphenyl ljInorganic < #From: Chronic Toxicity of Polyphenyl Mixtures, A. 'P|j kau, and J. Hoogstraten, Amer. Ind. Hyg. Assoc. J. 26: 3ft (July-August 1965). v present in animals on diets D and E whij gross hepatic disease was present in an mals on diets F, G, and H. In the preset] study, the renal and hepatic lesions are dl scribed in more detail. The ingestion of 3 mg/kg/day for a peric of 235 days (Test Group C) produced nil micropathological changes in any of the tji sues examined. A mean ingestion of 31 mg/kg/day (T Group D) led to the accumulation of fi| yellow-brown granules in the cytoplasm epithelial cells of the renal convoluted tubul| and loops of Henle, but no other patholog This aggregation of granules was appare in a small proportion of the epithelial eg and was seen in animals sacrificed at IS days. Those animals sacrificed at 188 an 235 days showed a progressive increase the number of cells so involved (Figure 1| The mean ingestion of 350 mg/kg/cj (Test Group E) led to a pronounced uj gree of renal d'sease. Although thd Table II Composition of Control and Polyphenyl Test Diets Group Control Diet Test Diet B A c D E F G H Diet Description Mean Amount of Polyphenyl Ingested (mg/kg/day) Male Female Pellets of Purina rat chow 0 Powdered Purina rat chow mixed with 0 corn oil in the ratio of 2/1 (w/w) Diet B with 0.01 wt.% Santowax OM 3.0 Diet B with 0.1 wt.% Santowax OM 31 Diet B with 1.0 wt.% Santowax OM 350 Diet B with 0.1 wt.% OMRE High Boilers 33 Diet B with 1.0 wt.% OMRE High Boilers 331 Diet B with 5.0 wt.% OMRE High Boilers 1832 0 0 3.5 37 409 38 386 2140 JanUary-February, j^gyinati industrial Hyt*ienr Assnria*inn Journal Table It . Composition of the Polyphenyl Mixtures Nonirradiated Weight Mixture % Irradiated Mixture Weal "r wax OM: Biphenyl o-Terphenyl m-Tfrphenyl p-Terphenyl 4.7 64.1 25.1 6.1 OMRG High Boilers: High Boilers Biphenyl o-Terphenyl m-Terphenyl p-Terphenyl Inorganic > 98 <(k 'l <#; u rom: Chronic Toxicity of Polyphenyl Mixtures, A. and J. Hoogstraten, Amer. Ind. Hyg. Assoc. J. 26: -August 1965). ill x \ ;ent in animals on diets D and E whi ;s hepatic disease was present in a s on diets F, G, and H. In the prei iy, the renal and hepatic lesions are bed in more detail. Tie ingestion of 3 mg/kg/day for a peri 235 days (Test Group C) produced :ropathological changes in any of the s examined. ! mean ingestion of 31 mg/kg/day (T( iup D) led to the accumulation of ow-brown granules in the cytoplasm thelial cells of the renal convoluted tubi 1 loops of Henle, but no other patholi is aggregation of granules was appari a small proportion of the epithelial cell 3 was seen in animals sacrificed at 1 /s. Those animals sacrificed at 188 j days showed a progressive increasi : number of cells so involved (Figure 17_ rhe mean ingestion of 350 mg/kgydij est Group E) led- to a pronounced ;e of renal d'sease. Although th Figure 1. Kidney from animal on diet E (350 mg Santowax/kg/day) for 130 days showing cystic dilatation of tubules. X 15 H & E 'olyphenyl Test Diets cnption Mean Amount of Polyphenyl Ingested (mg/kg/day) Male Female : chow 0 chow mixed with 0 io of 2/1 (w/w) :.% Santowax OM 3.0 % Santowax OM 31 % Santowax OM 350 % OMRE High Boilers 33 io OMRE High Boilers 331 OMRE High Boilers 1832 0 0 3.5 37 409 38 386 2140 Figure 2. Kidney from animal on diet E (350 mg Santowax/kg/day) for 188 days with more marked cystic distortion of renal tissue. X 15 H&E 10 January-February, 1 v^7 - Figure 3. Kidney from animal on diet E (350 mg Santowax/kg/day) for 188 days then control diet A for 47 days. There has been regression of the cystic change although this is not complete, and considerable scarring is apparent in the corticomedullary zone and pyramids. X 15 H & E r weight did not differ appreciably from the weight of controls, the kidneys of the test animals had a finely granular cortical sur face, an adherent capsule and a firm con sistency. The cortex was diminished in depth, and small cysts in the region of the corticomedullary junction could be seen by the naked eye. These changes increased with con tinued ingestion of this concentration of Santowax OM to 188 days. In these kidneys, areas of cystic dilatation were seen extending through the full thickness of the organ from the subcapsular region to the apices of the pyramids. Dilatation was maximal in the region of the boundary zone. (Figures 1, 2 and 3.) The lumen of the distal convoluted tub ules, loops of Henle, and collecting tubules contained an amorphous eosinophilic ma terial often possessing a yellow tinge. Histio cytes or effete remnants of neutrophil leuko cytes were often embedded within the intra tubular amorphous material which contained occasional colourless acicular crystals. (Fig ures 4 and 5.) The epithelium of the dilated tubules flattened or low cuboidal in configui a The epithelium of the distal ends of the lecting tubules showed marked metap so that it came to resemble the transit! epithelium of the calyces or renal (Figure 6). Translucent yellow pigj granules, similar to those observed aftej ingestion of lower concentrations of the were often present within the cytoplas tubular epithelial cells. Foci of lymphocytic infiltration were dent in the interstitial tissue, togethei accumulations of histiocytes containing, gregates of fine and coarse yellow pig granules within their relatively abu cytoplasm. There were no significant histopatho] changes seen within the glomeruli, ar and arterioles. Amorphous material \ the lumen of the tubules and most o yellow pigment in the epithelial cells. January-February, 19> ig fill Industrial Hy^icnr Atsnrialion Journal 11 al on diet E (350 days then control been regression of not complete, and nt in the cortico<15 H & E 4 and 5.) te epithelium of the dilated tubules w; ined or low cuboidal in configuratio: epithelium of the distal ends of the coi tg tubules showed marked metaplasi tat it came to resemble the transition lelium of the calyces or renal pely ure 1 6). Translucent yellow pigmei ules, similar to tho'sg observed after t ;tion of lower concentrations of the age: often present within the cytoplasm lar epithelial cells. ci of lymphocytic infiltration were in the interstitial tissue, together wi mulations of histiocytes containing aj ites of fine and coarse yellow pignu ales within their relatively abunch dasm. lere were no significant histopathologic ges seen within the glomeruli, arterii arterioles. Amorphous material wi' umen of the tubules and most of v pigment in the epithelial cells 1'iGi'Rh 1 Kidney from animals on diet E (350 nut Sanltm.ix ()\f/kg/day) for 130 days. The dilated (umnlutf-d tubules, loops of Henle and (ullec timr tubules contain masses of amorphous m.uiular debris with remnants of histiocytes and piilviniiiplionurle.ir leucocytes. X 100 H & E 12 January-February, 1969 American Industrial Hygiene Assoi y*'' t**S Figure 6, Diet E (350 mg Santowax OM/kg/ day) for 188 days. The epithelium of the collect ing tubules shows squamous metaplasia. Kidney X 290 histiocytes were intensely fuchsinophilic with the periodic acid Schiff (PAS) stain. This affinity was abolished by prior acetylation and restored following deacetylation. The pigment did not stain with Sudan IV in frozen sections and no hemosiderin was dem onstrable. Similar but more severe histopathological changes were apparent after the ingestion of 350 mg/kg/day over a period of 188 days. The animals of Group E who received San towax OM 350 mg/kg/day for 188 days and then were fed diet A until their sacri fice on the 235th day, established that the renal histopathology was to some extent reversible. Relatively few tubules exhibited cystic dilatation after the test animals had been returned to the Control Diet for 47 days. However, the renal parenchyma ex hibited a considerable degree of scarring and the interstitial tissue was heavily in filtrated with lymphocytes and histiocytes containing the PAS positive pigment gran ules. (Figures 7, 8, 9 and 10.) A benzene extract of an homogenate was made of a sample of kidney from this last group. Thin layer chromatography of extract showed the presence of orthometa-terphenyl. The meta-terphenyl present in trace quantities only. The cont kidneys were examined similarly and terphenyl was detected. OMRE High Boiler Sample A mean ingestion of 33 mg/kg/day 130 days (Test Group F) led to a percept it increase in the number of histiocytes with the hepatic sinusoids. These cells were la with abundant finely granular eosinophil cytoplasm and were multinucleated on casion. The cells occurred either singly in small groups and increased in numb with increasing length of exposure, to and 235 days. Nevertheless, there was no < tortion of hepatic lobular architecture this rate of dosage. (Figures 11 and 14 The cord cells of the liver showed ani: nucleosis and an undue prominence of nucleoli. Bile duct proliferation was not se The ingestion of 331 mg/kg/day (r Group G) led to the appearance of la v .A1 im " - Figure 7. day) for 188 days. The in ring and infls Figure 8. day) for 181 days. Accuir scarred renal Im/mf J'^friean Industrial Ilygren, Aquation Journal $-V. MSBlto&SV Mbs SS.-*5 k: Santowax OM/kg/ elium of the collectmetaplasia. Kidney up. Thin layer chromatography of ract showed the presence of ortho- ' :ta-terphenyl. The meta-terphenyl isent in trace quantities only. The coii Ineys were examined similarly and'l phenyl was detected. .-ws;' Figure 7. Diet E (490 mg Santowax OM/kg/ day) for 188 days--then control diet A for 47 days. The interstitium of the kidney shows scar ring and inflammation. 1IRE High Boiler Sample A mean ingestion of 33 mg/kg/day | 0 days (Test Group F) led to a percepl :rease in the number of histiocytes wi| e hepatic sinusoids. These cells were If th abundant finely granular eosinopj toplasm and were multinucleated onf sion. The cells occurred either singly small groups and increased in nun ith increasing length of exposure, to id 235 days. Nevertheless, there was no(| rtion of hepatic lobular architecture^ as rate of dosage. (Figures 11 and he cord cells of the liver showed jcleosis and an undue prominence of| ucleoli. Bile duct proliferation was not The ingestion of 331 mg/kg/day (r. roup G) led to the appearance of \z t t*'/.i.'t i mh ( ,. ' C-J "r - *< : .< Figure 8. Diet E (409 mg Santowax OM/kg/ day) for 188 days--then control diet A for 47 days. Accumulations of large histiocytes in the scarred renal interstitium. X 400 13 / 14 January-February, Kxhw'rfpan lndiistiial Ihvi.v, %* A s " f" \ Figure 9. Diet E (409 mg Santowax OM/kg/ day) for 188 days--then control diet A for 47 days. Accumulations of large histiocytes in the scarred renal interstitium. X 400 H & E Figure 10. Diet E--Interstitial and intratubu lar histiocytes with intracytoplasmic pigment gran ules. X 400 H & E Figure Boilers/kg Liver reta histiocytes Hpjpiacrophages ii fife pronounced i At 130 days jatare with a cent: tftV.-spdces was pr Spies of macropha in irregular .ne tlie normal arch ^Sfeiuclolobules. These "pfcjriegtdar aggreg ^jU:7dicl not show nor: " t)ftlJ.w:ih and perif tes -were more cl( ] S'ones where th ft, filliii ling the ce (I,'din./these regions i oil i i oasion, necrc 82 bands of histiocyt ' "Ceils reminiscent . 1 features becam *5 days (Figures 12 tion ol 1832 mg/kg l}:.caused a further acct )*}Pfjjcd t features so t , fcre.'seen by the naked , '"there was a greater tend HUttettn Industrial Hygiene Association Journal St`S5 2fflk i'.AV! Stex* 15 Figure 11. Diet F (33 mg O.M.R.E. High Boilers/kg/day) for 235 days. Liver X 100 P.A.S. Liver retains a normal achitectural pattern. Large histiocytes are present in the sinusoids. m 'toacrophages in the sinusIpire pronounced distortion of ppcleh At 130 days, the general PPjiVe .with a central vein and Bah spaces was preserved, but m|Ses. of macrophages transectgnobule in irregular meandering jpihe normal architecture and tie*dolobules. These small lobjrof'ifregular aggregates of hep- Hjjd not show normal orienta^^ral vein and peripheral portal ||fteSv were more closely packed zones where they formed jjjJMdli'cling the central veins. H0h< these regions were small, land on occasion, necrotic. At the tese bands of histiocytes elongated ftapeik cells reminiscent of fibrocytes J;JJhese features became more propat;235 days. (Figures 12 and 15.) IffStion of 1832 mg/kg/day (Test I t Uised a further accentuation of logical features so that hepatic i&lea Weie seen by the naked eye. At this there was a greater tendency of the histiocytes at the margins of the transecting bands to form spindle-shaped cells resembling fibrocytes. (Figures 13 and 16.) Reticulin stain demonstrated delicate reticulin fibres laid down in the long axis of the plump fusiform cells. Morphologically similar histiocytes were found in the spleens and bone marrows of all animals exposed to the O.M.R.E. High Boiler sample. The cells presented mainly in the lymphoid aggregates associated with the Malpighian corpuscles. The cells seen in the bone marrow tended to appear singly and to occur less frequently than those seen in the liver and the spleen. The mucosa of the stomach, small bowel and colon, the intestinal lymphoid tissue and the sinuses of the adrenal cortex were devoid of these histiocytes. In contrast to Santowax OM, the High Boiler sample produced no renal changes other than the accumulations of golden-yel low granules in the cytoplasm of the epithe lial cells lining the convoluted tubules and loops of Henle. The cytoplasm of the anom- 5 16 in -II January-February, 1969\ ' v`American Industrial Hygiene A: m Figure 12. Diet G (331 mg O.M.R.E. High Boilers/kg/day) for 235 days. Liver P. A. S. X 100. Although the general lobular appearance is preserved, the lobules are transected by broad bands of histiocytes to form small pseudolobules. HR ht\ Figure 13. Liver P. A. S. X 100. Diet H (1832 mg O.M.R.E. High Boilers/kg/day) for 235 days. There is disruption of the normal lobular pattern. The small pseudolobules are delineated by broad bands of histiocytes. ' alous macrophages within the Spleen contained translucent gc pigment granules. This material ' -tensely PAS positive in paraflR , prior acetylation rendered the ^ ' - negative but this property was ' ' (Jeacctylation. Digestion with 1 * ronidase and with diastase had r. the PAS positive quality of thes UThe cytoplasm was not Sudar --frozen section and selective stai: i./jjhbwed negative results. 1A benzene extract of an horr "'"Jjjje liver of an animal given 5/c Boilers for 235 days was s '-tibin layer chromatography. The ( Vttdncd a strongly fluorescent mat .!giot present in a similarly p i*!t-of control liver. The nature - has not been established. gt of a homogenate of the iyen Santowax OM cont (fluorescent material which value. Although these two lot been identified they ai Ip same material judging by Iporescent characteristics. Jssion Iff, Rfingestion by rats of 3 mg c jig/day for 235 days produ Be disease. The ingestion of gbr a similar period led to tl ttfbf a golden-yellow pigmeni Ijm of some of the renal tu .^Cumulation of this pigmt of little consequence to the jOii8neys, for it was accompa ^Sfipathological alteration^ . Th wHpment was not established. ,,ingestion of 350 mg.Santi led to very significant ; i-v*."^$v.ersible renal disease. Pigmen pH'-'Sltftilar to that observed with the | jJSOjration of ingested material v i-.'jPjt die major renal lesion consi 5 accumulation of amorphous, crys Cellular debris within portions of th 'Wtli associated gross cystic di tubules, metaplasia of epithelium lecting tubules, and an inflammato January-February, 196S can Industrial Hygiene Association Journal 17 ig O.M.R.E. High Liver P. A. S. X ular appearance is inserted by broad 11 pseudolobules. i. X 100. Wet H lers/kg/day) for 235 the normal lobular les are delineated by "alftilS "pl3froPhages within the liver and I' spjgen contained translucent golden-yellow I granules. This material stained in- p" pAS positive in paraffin sections. Icetylation rendered the cells PAS ^^KSthis property was restored by 3^7. Digestion with beta-glucu1^7 with diastase had no effect on Hpv6 quality of these granules. {WfegiT was not Sudanophilic on jglpvand selective stains for iron Iglive results. pf^extract of an homogenate of ||pft animal given 5% O.M.R.E. jjftifpr 235 days was subjected to ..jirdtnatography. The extract conj|jlthifelv fluorescent material which ent in a similarly prepared ex liver. The nature of this mabeen established. A benzene SBpmogenate. of the liver of a iimhwax OM contained some |t material which has a simiBjthough these two compounds |h identified they are probably Material judging by the differ ? characteristics. tion by rats of 3 mg of Santowax . for 235 days produced no dejl&e. The ingestion of 31 mg/kg/ gggiilar period led to the accumu- en-yellow pigment in the cy|Sme of the renal tubular cells, ulation of this pigment appears jpqorisequence to the integrity of JStfdr it was accompanied by no fipgjtcal alteration. The nature of Kf-tyas not established, istion of 350 mg Santowax OM/ B -to very significant and largely l||enal disease. Pigment deposition pM observed with the lower conof ingested material was evident, mtnajor renal lesion consisted of the (Pliffibn of amorphous, crystalline and . W debris within portions of the nephrons, . mtftsj associated gross cystic dilatation of tubules metaplasia of epithelium of the col lating tubules, and an inflammatory infiltrate in the interstitium. The cystic dilatation of tubules was reversible and regressed when Santowax OM was eliminated from the diet, but scarring and inflammatory infiltration of the interstitium of the kidney persisted. The marked alterations in the renal tubules and interstitium were not accompanied by micropathological changes in the glomeruli or renal vasculature. The histology of this lesion suggests that it is essentially a "chemical" nephrosis and interstitial nephritis induced by the accumu lation of irritant material and debris within renal tubules leading to cystic dilatation and with associated inflammatory reaction and scarring of the interstitial tissue. The fact that dilatation of the tubules and accumu lation of intratubular material regressed after ingestion of Santowax was discontinued fa vours the assumption that the dilatation of tubules is to a large extent the conse quence of mechanical obstruction. Dilatation may possibly be accentuated by diminished tubular absorption of glomerular filtrate. The exact nature of the contents of the obstructed tubules was not determined with any certainty, although one might speculate that some proportion of the contents con sist of terphenyl, metabolic products of terphenyl, or conjugates of terphenyl. There is at present no available method for the histochemical demonstration of these substances, but small amounts of terphenyl in the urine obtained directly from the blad der were detected by thin-layer chroma tography.8 When an homogenate of the kidney of an animal given the highest dosage of" San towax OM was submitted to gas chroma tography, ortho- and meta-terphenyl were found to be present, the latter in trace quan tities only. Recent work has also demon strated that unmetabolized terphenyl and in creased amounts of glucuronic and galacturonic acids are excreted in the urine of rats exposed to orally administered Santo wax OM.8 Some of the amorphous material within the lumen of tubules and within the cyto plasm of epithelial cells and histiocytes was intensely PAS positive. This staining quality "W 18 January-February, 1969 American Industrial Hygiene As; Figure 14. Diet F (33 mg O.M.R.E. High Boilers/kg/day) for 235 days. Liver P.A.S. Liver retains a normal architectural pattern. Large his tiocytes with fuchsinophilic cytoplasm are present in the sinusoids. Figure 16. Liver P. A. S. Diet H (1832 mg O.M.R.E. High Boilers/kg/day) for 235 days. There is accentuation of the features seen in Figure 15. At the margins of the linear aggregates of histiocytes, spindle-shaped cells are seen. was abolished by prior acetylation, but was restored by de-acetylation. Moreover, these reactions were evident in paraffin sections. It is therefore most likely that the PAS posi tive characteristic of this material is due to its carbohydrate content rather than an un saturated lipid. It is tempting to suggest that this accumulated material may be a glycuronide or galacturonide of terphenyl, par ticularly in the light of investigations on the metabolism of biphenyls and terphenyl,2'3'9 but this material may equally represent a carbohydrate-protein complex. The renal lesions induced by oral admin istration of Santowax OM were accompan ied by slight haematuria, glucosuria and polyuria. While the prolonged ingestion of Santowax OM in sufficient concentration led Figure 17. Kidney H & E. Diet E (350 Santowax OM/kg/day) for 188 days. Yello' brown, translucent pigment granules are present ij the tubular epithelial cells. tiocytic infiltration of liver, spleen lesser extent in bone marrow. ' rally, although these products of f % jngestion must be absorbed by t S.l jfltestinal tract, no storage of anon './! ierial was observed within histioc) 7 gas tro-intestinal lymphoid aggregate *'fjfl.the mesentery. The brunt of the umulation is borne by the liver f . I" the liver, the dense accumi '^histiocytes transected and distorted : tic lobules, and in time were eit ^F^med or replaced by fibrocytes, (grid cirrhosis. Hepatic parench Ibited a concomitant hypertr evidence of mitotic or prolife ff. The cirrhosis was not pr pfnpanied by perceptible celluk tty metamorphosis, gh Boiler ingestion at a dos; jll/day for 235 days led to f ulation of storage histiocyte 6sis or distortion of hepatic ari the deposition of storage |fogressive and accumulative, elv that a longer per'od of in EPpsage may have led to the sar Tftppearance achieved by the his H- to marked renal disease changes, no hist pathological changes were observed in liver or other viscera. Ingestion of O.M.R. High Boiler produced marked hepatic pat ology but no renal pathology other than t deposition of an unidentified yellow pigme: similar to that observed with Santowax O administration. It would appear that polymerized co: ponents of the High Boiler sample after beii| absorbed by the gastro-intestinal tract, aj cumulate within the cytoplasm of histiocyti but do not pass the glomerular filter, hen they do not cause pathological changes | the kidney. The accumulation of these products wit| in histiocytes produces lesions analogous the storage reticuloses with prominent his4 e ingestion of 3 mg of Santoi /day for 235 days produced n ble pathology in rats. ingestion of 31 mg' of I/kg/day for a similar peril accumulation of an unidenti low pigment in the, cytc j'^ppne renal tubular cells,: but Ifftectable changes. January-February, 190 jure 15. Diet G (331 mg O.M.R.E. rs/kg/day) for 235 days. Liver P. A. S. cells are iarge and show anisonucleosis. ophages are often multinucleated and cytoplasmic P. A. S. positive material. gure 17. Kidney H & E. Diet E (350 owax OM/kg/day) for 188 days, Yelll m, translucent pigment granules are presen| tubular epithelial cells. narked renal disease changes, no hit aological changes were observed in r or other viscera. Ingestion of O.M. h Boiler produced marked hepatic p fy but no renal pathology other than osition of an unidentified yellow pigm; ilar to that observed with Santowax m ninistration. t would appear that polymerized con lents of the High Boiler sample after bei|! orbed by the gastro-intestinal tract, aulate within the cytoplasm of histioc; i do not pass the glomerular filter, hei y do not cause pathological changes kidney. 'he accumulation of these products witl histiocytes produces lesions analogous storage reticuloses with prominent hi ttfifan Industrial Hygiene Association Journal m_ 19 'infiltration of liver, spleen, and to a 'isftent in bone marrow. Paradoxipigh these products of High Boiler pflt be absorbed by the gastro- no storage of anomalous majM^ved within histiocytes in the M lymphoid aggregates or with- 3. The ingestion of 350 mg of Santowax OM/kg/day caused pathological changes in the kidney consisting of tubular ob struction by precipitated products of San towax OM and an irreversible interstitial nephritis with scarring. K; The brunt of the histiocytic 4. In contrast to Santowax OM, the in p'borrte by the liver and spleen. gestion of 33 mg O.M.R.E. High Boiler the dense accumulations of sample/kg/day led to an histiocytic stor ||sected and distorted the hepa- age disease with minimal or insignificant |3 in time were either trans- renal pathology. The sequence of events ij^fied by fibrocytes, leading to in the rat l'ver indicates that the trans / Hepatic parenchymal cells formation or replacement of accumulated Jneomitant hypertrbphy but histiocytes in the liver by fibrocytes leads j^of mitotic or proliferative ac- to a florid monolobular cirrhosis con ihbsis was not preceded or sisting of "false" lobules. The cirrhosis By perceptible cellular necrosis was not preceded or accompanied by per Jnprphosis. ceptible cellular necrosis or fatty meta Ingestion at a dosage of 33 morphosis. ; 235 days led to progressive B; storage histiocytes but no Jjfeiqn of hepatic architecture. Hrtion of storage histiocytes 5 and accumulative, it is not j-JIfiiger per od of ingestion of jllfifive led to the same cirrhoRfichieved by the higher daily f`"on of 3 mg of Santowax OM/ '235 days produced no demonIthology in rats. tion of 31 mg of Santowax for a similar period led to filation of an unidentified gold|^|pigment in the cytoplasm of `idL tubular cells, but no other changes. References l. Haley, T. J-, L. E. Detrick, N. Komesu, P. Wil liams, H. C. Upham, and L. Bawmash: Toxicologic Studies on Polyphenyl Compounds Used as Atomic Re actor Moderator Coolants. Toxicol, and Applied Phar macol. 1: 515 (Sept. 1959). 2. Gerbaulet, K., and P. Sgoppa: Toxicity of Organic Coolants. Euratom, Joint Nuclear Research Centre, Ispra Establishment, Italy Biology Service. 3. Cornish, H. H., R. E. Baqor, and R. C. Ryan: Tox icity and Metabolism of Ortho-Meta and 'Para-terphenyls. Amer. 2nd. Hyg. Assoc. J. 23: 372 (1962). 4. McEwan, M.: Organic Coolant Databook Technical Publications AT-1, Section 2-1-1 pp. 1, Monsanto Chem ical Company, St. Louis (July 1958). 5. Petkau, A., and J. Hoogstraten: Chronic Toxicity of Polyphenyl Mixtures. Amer. 2nd. Hyg. Assoc. J. 26: 380 (1965). 6. International Commission on Radiological Protection: Report of Committee II on Permissible Dose for Inter nal Radiation. Table I, pp. 41, ICRlP Publication 2, Pergamon Press, New York (1959). 7. Keen, R. J., R. A. Baxter, R. H. J. Gercke, and W. L. Orr: Radiolysis Products of Polyphenyl Coolants, Part I, In-Pile Loop Irradiations, Report NAA-SR-4355. pp. 5, Atomics International, Canoga Park, California (March 1962). 8. Petkau, A., and H. L. Rayner: The Fate of Terphenyl in the Rat. AECL Publication 2507 (Nov. 1965). 9. West, H. D., J. R. Lawson, I. H. Miller, and G. R. Mathara: The Fate of Diphenyl in the Rat. Arch, of Biochem. and Biophysics 60: 14 (1956). K*bUiisfKp'" * .