Document pp4GorQnyVqjRJX6yR6V8voDX

S- .?-i.vt- -a _ +& " - V ;After CuirenfTable_ * . ,, INDUSTRIAL HEALTH NEWS - ' fcSSiSfef.' '"-or'* # ` - . :-i*r .4 .*. Jr'r. ? LITERATURE ABSTRACTS '-3l<S MEDICAL <iy fe?*?vU vW' ^ " ... engineering . .-"^s*f*csaascssr . CHEMICAL wf ' -.s.*? . J>V 4': - ` '.a.:--- TOXICOLOGICAL .... .* -- LEGAL r *" ...... MARCH, 1969 (VoL 33, No. 3) INDUSTRIAL HYGIENE FOUNDATION 8231 CENTRE AVENUE PITTSBURGH, PA. 1S232 Stacks-Aftsr Current Tebie SCF-ALLF-03120 March. it. C^rr,. arv J m jr.s ;i*:*'*` . *r'- vWrtatos or Ferruginous Bodies. E. A. Gaensler and \V. VV, Addington -r^r?r-gi. Med. -idO. 4dd-4'2 (Feb. 27, 17691. ` 3litom.aeeous earth, graphite ar.d carborundum have been Identified as the core of typical asbestos bodies" Inman. Substances believed to be biologically inert, Including fibrous aluminum silicate, fibrous glass, silicon carbide and foraterite have caused ferruginous bodies hamsters and guinea pigs. Even fragments of the lung's own elastic tissue may produce elastosis bodies" that lock similar. Technics are now available for analysis of the core fibers. -_uey include electron beam and x-ray diffraction, laser microprobes, ultrasonic disintegration jnd mass spectroscopy. The electron-beam diffraction patterns of ferruginous bodies from 22* lungs of "unexposed'1 persons did not coincide with that of chrysotile. Since 95 per cent of asbestos used in the United States is of this type, it was concluded that the vast majority of ferruginous bodies found at random autopsies are not from asbestos. Obviously, the diagnosis jf asbestosia, based on the finding of ferruginous bodies in an apparently unexposed person, must be made with caution. However, one must be equally cautious in making a diagnosis of nonspecific interstitial pneumonitis" in a person with known exposure because there is no relation between the number of bodies and the severity of asbestos pneumoconiosis. On the contrary, ws and others have noted an inverse relation. In persons with prolonged but distant exposure, often retired because of respiratory impairment, the lungs frequently show severe fibrosis with only rare asbestos bodies whereas in patients with more recent exposure, lung -iopsy reveals alveoli filled with bodies and debris-laden macrophages but little or no fibrosis. This paradox can be explained In a number of ways. The small number of asbestos bodies in workers with fibrosis who were exposed long ago may be the result of clearing of the intra- ilveolar material. This clearing occurs most rapidly in areas of supple alveolar walls whereas it is delayed In the more noncompliant regions near the thickened pleura and around larger vessels ar.d bronchi. Therefore, the distribution of asbestos bodies is uneven, and their number .n any section need not be representative. The reLation between the number of visible asbestos 53dies and the degree of fibrosis is also poor because only a very small and variable fraction of fibers become coated. Probably the tiniest, uncoated particles, which are Invisible by light microscopy, are most fibrogenic because they have the largest aggregate surface area. This U important because at some stage a chemical reaction must initiate the process of fibrosis. The visible asbestos bodies, therefore, are best considered as markers, rather than as im portant causative agents. In 1929 W. E. Cooke !said that "curious bodies have been found in .very necropsy in pulmonary asbestosis, and the problems we have to decide are, first, what the bodies are, and second, whether they are diagnostic of asbestosis." Although at first anivers seemed deceptively simple, new information Increasingly has raised new questions. Tv.at asbestos bodies may contain asbestos U clear. It Is equally clear that structures appar- mt.y indistinguishable from asbestos bodies may have as their core other materials. Unfor- irately, the methods of Identification are exceedingly complex, and, even In the best hands, r.m.ts remain tentative. Nevertheless, recent animal exposure and analytical work suggests it. until asbestos has been identified as the core of an "asbestos body, " It is best to use the "re general term "ferruginous body. " There are 27 references. --Cond. from text : ibrosis of lungs due to inhalation of asbestos dust. Brit. M. J. 2:147, 1924 Lj^e Community Hazards of Asbestos. J. Cuthbert. ::r.ch. med. Wochschr. 109, 1369-1372 (April-June, 1967). German. "-e inhalation of asbestos is far more dangerous than is generally recognized by the public, :-ce even a transient period of exposure can lead to disease (interstitial fibrosis of the lung, tir.cer, mesothelioma, endothelioma of the pleura and the peritoneum, painful dermal '-si ar.d death many years later. Electron microscopic studies nave shown that for every '-* fiber recognizable under an ordinary (tight) microscope, there are hundreds of tiny r :r.iced particles, which dust experiments with guinea pigs have shown to be just as i: as the larger fibers. '.S'hlle the asbestos industry has taken energetic measures toward ' -.rever.tlon of classical forms of asbestosis by dust elimination in its plants (vacuum removal --st, use of gas masks, automation of manufacturing processesl, such prophylactic >i-res have not prevented the gradual long-term development of cancer In persons who come -:isi-jr.al, slight, tr temporary contact with asbestos. ; his group certainly includes ' soestos workers ar.d all persons r.g within 1. 5 km of an asbestos plant: these persons usiria-' Hvjiene Oicest tend to succumb to mesothelioma after man/ years of such contact. A numbsr -:i examoles ar- giver., includinc those of carpenters ar.d vr.s tr-stien workers, who do not realize that their relatively brief contact ir. sawing or hanc.tr.; asbestos materials car. lead to lung cancer rr.ar.y years later. The great increase ir. asbestos production and in asbestosis in recent years is tabulated; the need for utilization of alternate materials in industry, and for further research on biological effects is emphasized. The presence ir. asbestos of carcinogenic oils and other components, including benzopyrene and chromium, is mentioned. --APCA Absts, 283 Asbestos Exposure and Pteurai Mesotheliomas. R. H. Mortimer and C. 3. Campbell. Med. J. Australia 2. 720-722 (Oct, 26, 19o6). Diffuse pleural mesothelioma is reported in two patients exposed to asbestos dust. The neo plasmas were dissimilar in macroscopic and histological appearances. Criteria for classi fication as mesotheliomas are presented. Asbestos bodies were found in the lungs of both patients, but minimal interstitial fibrosis was present. --J. Am. Med. Assn. References U Reviews 284 Prevalence of Asbestos Bodies in Basat Lung Smears. A. Poltiack and M. I. Sacks. Israeli. Med. Scl. (Jerusalem) 4, 223-226 (March-April, 1968). Asbestos bodies were found in basal lung smears in 26 of 100 consecutive adult autopsies in Jerusalem. They were present in 29. 1% of males and 22. 2% of females, and were more fre quently encountered in Ashkenazi than in non-Ashkenazi Jews. Asbestos bodies, when presen;, were usually scanty (less than 10), and in only two males were more than 30 bodies found unde.* low power. The five subjects with more than ten asbestos bodies each were all Ashkenazi Jew* The prevalence of asbestos bodies is compared with Cape Town, Pittsburgh, Miami, Montreal. Glasgow, and Jerusalem. Highest frequency found is in Montreal (48%) and may reflect dif ferences in the degree of atmospheric pollution. --APCA Absts. 285 Pathological Symptoms Due to Inhalation of Asbestos Dust. H. Bohllg. Zentr. Arbeitsmed. u. Arbeitsschutz. 1_6. 353-355 (Dec., 1966). In brief literature review, in which authors are mentioned but no references cited, the probls' of asbestos dust as a carcinogenic substance is surveyed. Despite greatly increased prevenii'4 measures taken in many asbestos plants, and the resultant reductions in cases of asbestosis, problems of asbestos inhalation have acquired new significance during the past five years. T*1'. retrospective examination of mesothelioma autopsy material in various :ountries has impH*9"' asbestos dust as a malignant-tumor inducing agent, not only in asbestos workers but even i* ^ others. The well-known "pleura-plaques" of asbestosis and diffuse mesotheliomas have bee- observed in individuals who had never had occupational contact with asbestos but who had re sided in the vicinity of asbestos plants or mines. It can be stated with assurance that polluh05 of the ambient air (emission) by asbestos factories--which were relatively late in utilizes tn^ asbestos dust of their dedusting Installations instead of simply releasing it to the atmosph*** has been a causative factor in a significant increase in the rate of appearance of both pl*ur*' plaques and mesotheliomas. Whether or not the quantities of asbestos dust released into * atmosphere from brake linings of automobiles are also responsible for these malignancy** ` a question which has yet to be determined: however, asbestos was detected histologically t the lungs of city dwellers not exposed occupationally in the following percentages; Pittsbc-> 41.0%; Miami, 27.9%; Cape Town, 26.4%. Individuals endangered by asbestos, in addlt'0*^ those just cited, include persons who have occasional contact with asbestos in construeti*n other activities (such as roofers, insulation specialists). The properties of asbestos or*9- including their benzopyrene content, are briefly mentioned. -APCA A*8' 286 Asbestos 3odies in the Lungs ar.c Mesothelioma. A Retrospective Examination o Autopsy Material. I. Kagerstrand, L. Meurman, and B. Odlur.d. Acta Pathol. Microbiol, Scand. (Copenhagen: 72. (2). 177-15. i;9os). Ir. 12,763 autopsies performed during 1 05?-oc at the General Hospital, M'alrr.o, Swedercases of mesothelioma were found (2" o: the pleura, i of the peritoneum) for a freouenc^ 0.27". (C. V if children under .5 years of age are excluded). Of these, 34 were re-*5*8' i >