Document 1QEK6rxXgoYEK0jr5wwqDkpqm

Asbestos Bodies in Human Lungs at Autopsy Dzidra Cattna, MD, Robert S. Totten, MD, and Paul Cross, MD 371 The incidence of asbestos bodies in the lungs was in* products such as asbestos 'roofing, roof tiles, ceil vestigated in 100 autopsies of adults. Lung smears were ings, floor tiles, pipe and electrical insulation, car- taken from the sectioned surfaces of the upper and lower brake linings, cement, etc. Since asbestos is vir lobes of both lungs. The slides were dried and mounted tually indestructible they predicted that the without staining, and approximately 400 low-power fields amount of air-bome asbestos fibers in cities would were examined in each slide. Routine histological sections increase in the future and become a contaminant of of unexpanded lungs were also examined in all cases. As the air. They further suggested that the results of bestos bodies were found in 41% of the subjects. They life-long inhalation of these fibers might lead to were not encountered in persons up to 24 years of age. almost universal basal asbestosis in adults, and a Among males the incidence was 47%, and in females frequency of mesothelioma of pleura or peritoneum 34%. Although significant microscopic pulmonary fibrosis higher than that of bronchial carcinoma today. As was encountered in two positive cases, no instance of bestos has also been implicated as a possible factor classical asbestosis was found. Mesothelioma of the pleura was not encountered. Primary lung carcinoma oc See also page 419. curred in one patient with asbestos bodies and in one in the development of carcinoma of the lung.4 without. According to Doll* the risk of developing a lung cancer is increased among asbestos workers, but Wagner and associates1 reported on the occur this is denied by others.*-7 rence of diffuse pleural mesothelioma in per As the United States accounts for roughly over sons from a large asbestos mining area in tohnee third of the world's consumption of asbestos, northwest of Cape Province, South Africa. Since Thomson* initiated an investigation of the fre mesothelioma of the pleura was regarded as an un quency of asbestos bodies in lungs in Miami, Fla, common tumor, and was rarely seen elsewhere in South Africa, they undertook an investigation of these cases. In ten cases, lung tissues were available where even higher positive figures were obtained than in Cape Town. Pittsburgh and its environs are free of asbestos for microscopic examination and asbestosis was mines, but it is a large industrial center with an found in eight. expanding modem building program. The purpose Thomson1 reported seven cases of mesothelioma, of this investigation was to obtain preliminary four in the pleura and three in the adjacent perito data on the incidence of asbestos bodies in the neum, encountered over a period of three years in lungs of patients who died at Presbyterian-Univer- the autopsy service of one teaching hospital in sity Hospital. Cape Town. In all seven cases the microscopic pic ture was that of pulmonary asbestosis, with abun Material and Methods dant asbestos bodies and fibrosis in the basal por The work was carried out in the Presbyterian- tions of the lower lobes. Since only one of these University Hospital, which receives patients main seven patients had a history of occupational ex ly from the city of Pittsburgh and the surrounding posure to asbestos, Thomson and his associates1 * area. Hie material consisted of 100 routine autopsy undertook an investigation on the frequency of asbestos bodies in the lungs in general population of Cape Town in routine autopsies. Of 500 cases examined, 132 were positive for asbestos bodies. These results suggested that asbestos was becom ing a modem urban hazard. According to Thomson et al,s world consumption of this mineral had in creased from 300,000 tons in 1934 to 2,400,000 tons in 1961. It is used in a wide variety of industrial From the departments of pathology. Presbyteriao-University Hospital and University of Pittsburgh School of Medicine (Drs. Cauna and Totten), and Industrial Hygiene Foundation. Inc.. Mellon Institute (Dr. Gross). Pittsburgh. Reprint requests to 230 Lothrop St, Pittsburgh 15213 (Dr. Cauna). JAMA. May 3. 1965 Vol 192. No 5 1. Incidence of positive cases relative to age groups. i' . Ill p PA-242.20 SCF-FA-5670 FOS 0009526 372 ASBESTOS BODIES--CAUNA ET AL A#e 15-24 25-34 35-44 45-54 55-4* 65-74 Over 74 Total % Table 1.--Distribution of Asbestos Bodies in Lung Smears According to Age and Sex Males Females Both Seies ' Positive 4 3 2 9 3 4 25 47% Negative 6 1 6 1 6 5 3 28 53% Total 6 5 9 3 15 8 7 * 53 100% Positive ) 3 1 4 5 2 16 34% Negative i i 4 5 7 11 31 66% Total 3 1 4 5 9 12 13 47 100% ' Positive 5 6 3 13-- 8 .6 Ti 41% Negative 9 1 7 5- ir~ 12 14 59 59% Total 9 6 13 b 24 2C 20 100 100% cases, 53 men and 47 women, ranging in age from 17 to 91 years. Twelve subjects were Negroes. The occupation of the women was given as housewife in most cases, those of the men ranged from manual workers to executives. In no case was any connec tion established with manufacture of asbestos prod ucts, although the occupations were taken from the charts, and neither the patients nor their families were questioned directly. The presence of the as bestos bodies was determined by the use of lung smears9 taken from the upper and lower lobes of both lungs (four slides from each case). The smears were obtained by an incision into the lung tissue from which a small quantity of blood or edematous fluid was expressed onto a glass slide and spread evenly over an area approximately 12 sq cm. The slides were air-dried and mounted without staining. In each slide approximately 400 low-power (16-mm objective) fields were examined, and the total num ber of asbestos bodies was registered. Some smears were stained for iron (Pearls reaction) which colored the iron-containing protein globules blue. Routine histological sections of unexpanded lungs stained with hematoxylin and eosin were also ex amined in all cases. Results The problem of absolute identification of asbes tos in asbestos bodies is a difficult one, and to our knowledge no successful histochemical procedure has been devised. Chemical examination of lung tissues for add insoluble residues yields a value for total silica that might represent asbestos or other silicates. No chemical determinations were done in these cases. An attempt was made to identify the element silicon in asbestos bodies (from a known case of asbestosis) by electron probe analysis. Al though iron was readily identified, no silicon was encountered.* The bodies seen in talcosis are identi cal to those in asbestosis and are thought to be the result of contamination with tremolite, another fibrous silicate. It is possible that the bodies seen in our material are assodated with tremolite. With the above limitations in mind, the term asbestos body is used here to mean the typical segmented, iron-en crusted structure known to be assodated with clini cal and experimental asbestosis. Asbestos bodies were found in 41 of the 100 sub jects. The inddence of positive cases was higher in men, 47%, than in women, 34%. Up to the age 112 of 24 years (six persons) no asbestos bodies were encountered. These data are summarized in Table 1. Considering the age groups separately, the high est relative incidence of positive cases was found between 25 to 34 years as compared with any other age group (Fig 1). Since these are all relatively small groups the significance of the differences is doubtful. Positive cases were more frequent among man ual workers than among professional and adminis trative occupations. The number of Negro subjects was only 12, but in seven subjects asbestos bodies were encountered. In the majority of the positive cases, one to ten asbestos bodies were found (Table 2). The maxi mum number of 473 was counted in a male subject, aged 63 years, whose occupation was a sales engi neer for a pump company. However, no particular importance can be attached to the actual frequency of the asbestos bodies encountered in each case because the concentration of the bodies depends on the site from which the smear is taken and on the amount of edema and congestion in the lung at the time of death.9 In this investigation samples were not taken specifically from the basal portions of each lobe, where the number has been reported to be highest, but from random sites. In the lung smears, asbestos bodies were readily recognized, because of their typical orange-brown color and segmented appearance (Fig 2). They were often partly enclosed by macrophages. Only those cases with typical bodies such as seen in Fig 2 were accepted as positive. In some positive and some negative cases, atypical elongated structures were seen, but these were not considered as asbestos bodies. In 24 positive cases, some macrophages Table 2.--Number of Asbestos Bodies Found in Positive Cases* NOe Of Asbestos Bodies 1 MO 11-20 29 9 36 41 51 473 ,, Males 7 14 1 ..1 .. 1 1* Females 6 6 2 1 1 Total 25 16 *1.600 low power field! eeomined in each ceae. 1P . Total 13 20 3 1 1 1 1 1 41 JAMA. May 3. 1965 o Vol 192. No 5 FOS 0009527 I V* 2. Asbestos body intimately related to a macrophage. Unstained lung smear of 65-year-old white scrap-iron dealer (x 1.736). contained coarse orange-brown granules, which also gave a positive iron reaction. Macrophages with these coarse iron-containing granules were also found in smears of six negative cases. In histological sections of lung tissues asbestos bodies were found in only four positive cases, all among the higher counts. These bodies were situ ated within the lumina of alveoli and were usually partly enclosed by macrophages as in the smears (Fig 3). Interstitial fibrosis of some significance was observed in only three cases, two of them with asbestos bodies (three and four respectively) in the lung smears, and very few macrophages with coarse granules. In the third case with fibrosis, as bestos bodies were not found, but macrophages with coarse brown granules were seen in smears and his tological sections. No case of classical asbestosis was found and mesothelioma of pleura was not encountered. Primary lung carcinoma occurred in one case with asbestos bodies and one without The fate of asbestos bodies in the lung is as yet not known. According to Knox and Beattie,lo and Holt et al," the bodies disintegrate after a period of time producing a large number of fragments which are collected in phagocytes. In our material, macrophages frequently contained coarse brown granules in asbestos positive and also in some nega tive cases. These granules gave a positive iron re 3. Asbestos body intimately related to a macrophage Inside an alveolus. Stained lung section of 57-year-old unemployed white male (x 1,736). action, and judging by their size, they could consti tute fragments of disintegrating asbestos bodies. However, since demonstration of iron in the coarse granules is not a positive identification of fragments of asbestos bodies, the question cannot be settled. On the basis of their experiments with rats. Holt et al," suggested that fibrosis of the human lung was not caused by asbestos bodies, but by small asbestos particles, derived from the break-down of these bodies. In our limited material no correlation between the presence of asbestos bodies or macro phages with coarse brown granules and pulmonary fibrosis was determined. The overall incidence in this Pittsburgh series of 41% asbestos positive cases substantially exceeds that of Cape Town with 26.4 %J and Miami* with 27.9%, the only two localities where this type of information is available for comparison so far. This may merely represent a difference in technique among the three groups or perhaps reflect a real difference in atmospheric pollution among the three cities. In any event the figures from these three widely separated urban communities indicate that asbestos bodies are commonly encountered in hu man lungs. It is suggested therefore that studies of this modem air contaminant should be extended. This investigation was supported in part by Public Health Service grant HE-06675. References 1. Wagner, J.C.; SIeggs. C.A.: and Marchand. P.: Diffuse Pleural Mesothelioma and Asbestos Exposure in the North West Cape Province. Brit J Induttr Med 17:260-271 (Oct) I960. 2. Thomson. J.G.: Mesothelioma of Pleura or Peritoneum and Limited Basal Asbestosis. S Afr Med J 36:759-760 (Sept) 1962. 3. Thomson. J.G.; Kaschula. R.O.C.: and MacDonald. R.R.: Asbestos as Modem Urban Hazard. S A/r Med J 37:77-81 (Jan) 1963. 4. Isselbscher. K. J.; Klaus, H.: and Hardy, H.L.: Asbestosis and Bronchogenic Carcinoma. Amer J Med 15:721-732 (Nov) 1953. 5. Doll. R.: Mortality From Lung Cancer in Asbestos Workers. Brit J Induttr Med 12:81-86 (April) 1955.6 * 6. Lanza. A.J.: Pneumoconiotit. New York: Grune & Stratton. Inc.. 1963. p 24. 7. Braun. D.C.. and Truen. T.D.: Epidemiological Study of Lung Cancer in Asbestos Miners, Arch Indutt Health 17.-634-653 (June) 1958. 8. Thomson. J.G.: Asbestos and Urban Dweller, read before the Conference on Biological Effects of Asbestos. New York. Oct 19. 1964. 9. Vassamillet, L.F.: Personal communication to the authors. Jan 15. 1965. 10. Knox. J.F., and Beattie, J.: Distribution of Mineral Parti cles and Fibers in the Lung After Exposure to Asbestos Dust. Arch Indutt Hyg 10:30-36 (July) 1954. 1L Holt. P.F.: Mills. J.; and Young, D.K.: Early Effects of Chrysodle Asbestos Dust on Rat Lung, J Path Baet 87:15-23 (Jan) 1964. . ` JAMA. May 3, 1965 Vol 192. No 5 113 FOS 0009528