Document ExgDo9G0bNnNz8qXwMrr8Bo1L

INDUSTRIAL HYGIENE FOUNDATION SS2M31I CCEENNTTRREE AAVVEENNUUEE PITTSBURGH, PA. 15232 Stacks-Aftsr Current Tab:2 rialJilSiS. r.e Digest INDCSTRIAL DUSTS March. 1^6? or Ferruginous Bodies. E. A. Caensier and \V. W. Addington, j. Med. '30. 488-4U(Feb. 27. 19691. roTiaceous earth, graphite and carborundum have been identified as the core of typical J -bestos bodies'1 in man. Substances believed to be biologically inert, including fibrous , .fpjnum silicate, fibrous glass, silicon carbide and forsterite have caused ferruginous bodies f*\arnsters and guinea pigs. Even fragments of the lung's own elastic tissue may produce l"eU5tosis bodies" that look similar. Technics are now available for analysis of the core fibers, -u v include electron beam and x-ray diffraction, laser microprobes, ultrasonic disintegration 1". mass spectroscopy. The electron-beam diffraction patterns of ferruginous bodies from 22 *aa a "unexposed" persons did not coincide with that of chrysotile. Since 95 per cent of "U bestos used in the United States is of this type, it was concluded that the vast majority of **rruginuS bodies found at random autopsies are not from asbestos. Obviously, the diagnosis jf asbestosis, based on the finding of ferruginous bodies in an apparently unexposed person, --ust 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 lation between the number of bodies and the severity of asbestos pneumoconiosis. On the ontrary. we 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 jbrosis with only rare asbestos bodies whereas in patients with more recent exposure, lung \03Sy. 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- i veoiar 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 and bronchi. Therefore, the distribution of asbestos bodies is uneven, and their number in any section need not be representative. The relation between the number of visible asbestos bodies and the degree of fibrosis is also poor because only a very small and variable fraction of libers become coated. Probably the tiniest, uncoated particles, which are invisible by light --.icroscopy, are most fibrogenic because they have the largest aggregate surface area. This is 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 every 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 an swers seemed deceptively simple, new information increasingly has raised new questions. That asbestos bodies may contain asbestos is clear. It is equally clear that structures appar ently indistinguishable from asbestos bodies may have as their core other materials. Unfor tunately, the methods of identification are exceedingly complex, and, even in the best hands, .--suits remain tentative. Nevertheless, recent animal exposure and analytical work suggests t-.at, 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 Fibrosis of lungs due to inhalation of asbestos dust. Brit. M. J. 2:147, 1924 - ne Community Hazards of Asbestos. J. Cuthbert. ':nch. med. Wochschr. 109, 1369-1372 (April-June, 1967). German. he 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, ~z cancer, mesothelioma, endothelioma of the pleura and the peritoneum, painful dermal ':"st ar.d death many years later. Electron microscopic studies have shown that for every : s liber recognizable under an ordinary (light) microscope, there are hundreds of tiny '-mized particles, which dust experiments with guinea pigs have shown to be just as V a- the larger fibers. While the asbestos industry has taken energetic measures toward '"ever.tion of classical forms of asbestosis by dust elimination in its plants (vacuum removal ' dust, use of gas masks, automation of manufacturing processes), such prophylactic ---res have not prevented the gradual long-term development of cancer in persons who come tistor.al, slight, or temporary contact with asbestos. This group certainly includes ' is'oestos workers and all oersons living within 1. 5 km of an asbestos slant; these oersor. .dustrial Hveiene Dicest tend to succumb to mesothelioma after many years o: such contact. A number examples ar given, including those of carpenters and construction workers, who c j not realize that their relatively brief contact ir. sawing or handling asbestos materials can lead to lung cancer many 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 in asbestos of carcinogenic oils and other components, including benzopyrene and chromium, is mentioned. --APCA Absts. 283 Asbestos Exposure and Pleural Mesotheliomas. R. H. Mortimer and C. 3. Campbell. Med. J. Australia jl, 720-722 (Oct. 26, 1966). Diffuse pleural mesothelioma is reported ir. 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 fc Reviews 284 Prevalence of Asbestos Bodies in Basal Lung Smears. A. Polliack and M. I. Sacks. Israel J. Med. Sci. (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 present, 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 Je* 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. Bohlig. Zentr. Arbeitsmed. u. Arbeitsschutz. 16. 353-355 (Dec., 1966). In brief literature review, in which authors are mentioned but no references cited, the proble of asbestos dust as a carcinogenic substance is surveyed. Despite greatly increased prevesti'- 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. retrospective examination of mesothelioma autopsy material in various countries has imphc*tf' asbestos dust as a malignant-tumor inducing agent, not only in asbestos workers but even tn ^ others. The well-known "pleura-plaques" of asbestosis and diffuse mesotheliomas have >**" 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 of the ambient air (emission) by asbestos factories--which were relatively late in utili*i8 ^ asbestos dust of their dedusting installations instead of simply releasing it to the atmosph*r* has been a causative factor in a significant increase in the rate of appearance of both pleur*' plaques and mesotheliomas. Whether or not the quantities of asbestos dust released into atmosphere from brake linings of automobiles are also responsible for these malignancie* 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; Pittsbo-^ 41.0%; Miami, 27.9%; Cape Town. 26.4%. Individuals endangered by asbestos, in additt0, ^ those just cited, include persons who have occasional contact with asbestos in construct!00 other activities (such as roofers, insulation specialists). The properties of asbestos are, including their benzopyrene content, are briefly mentioned. --APCA -A3 286 Asbestos Bodies in the Lungs and Mesothelioma. A Retrospective Examination o: a ----------- Autopsy Material. I. Hagerstrand, L. Meurman, and B. Odlur.d. (. Acta Pathol. Microbiol. Scand. (Copenhagen) _72. (2). 177-I9i (1965). In 12. 763 autopsies performed durir.c lc:7-io at the General Hospital, Maimo, Sweoer-' . cases of mesothelioma were found (27 of the pleura. 5 of the peritoneum) for a frepuer""^ ;,f0.27Fr (0. 3% if children under :5 years of age are excluded). Of these, 34 were re-e' > ">