Document M4eyJzdmeJZ6y66xY1MKJ3QoV

DUST AND FERRUGINOUS BODY QUANTITATION--GROSS ET AL 89 Although the occurrence of ferruginous Identification of both the naked fibers, as bodies and of naked fibers in the lungs of well as the cores of ferruginous bodies de dty dwellers has not been associated with rived from lungs of these urban dwellers, disease ascribable to the inhalation of will be studied and reported in a future fibrous dust particles, the suspicion has been paper. publicized that pulmonary fibrosis and can cer may develop in the lungs of city dwellers Materials and Methods from the inhalation of this fibrous dust pre sumed to be asbestos.4-5 While studying the sediment derived from the digestion of lung tissue, we were im Preparation of Dry Lung Tissue.--Formalde hyde-preserved lungs were washed with run ning tap water for 24 hours and then cut into thin slices by means of a meat slicer. The slices pressed with the large number of naked were extracted with three portions of acetone transparent fibers, most of which were less and three portions of dry ether for six to eight than 8/1 in diameter and less than 60p long. These had no distinguishing features that enabled us to differentiate asbestos from nonasbestos fibers at the magnifications em ployed (x 450). Subsequently, however, we have been able to do this readily with the electron microscope.6 Having shown that at least some of the fibers inhaled by urban dwellers are probably asbestos, we sought to day6, vacuum dried at 60 C for 48 hours, and then weighed. Isolation of Dust From Lungs.--The defat ted, dried lung tissue was digested by heating with formamide according to the method of Thomas and Stegemann.6 However, in order to remove more of the associated impurities and to render the dust more readily dispersible, it was subjected to more vigorous washing. In addition to the solvents used by Thomas and determine how much fibrous dust was in Stegemann, we used a methanol-chloroform haled by these people during their lifetime mixture to wash the dust. This additional ma and what was the size distribution of the fibers. We also wished to study the relation ship of the fibrous dust (1) to the total dust inhaled, (2) to the number of ferruginous bodies found, and (3) to any possible pul monary disease present. To answer these questions, we first had to develop a method for quantitatively separat ing the transparent fibers from the carbona nipulation resulted in the removal of some unidentified brown colored impurities and made the dust more easily dispersible. The procedure was carried out as follows: about 30 gm of dry tissue was placed into a 2.000-ml flask containing 1,000 ml of dry for mamide (Fisher, reagent grade), and the mix ture was kept under continuous stirring at 130 6 C for 72 hours. The resulting liquid digest was centrifuged in 200-ml flasks at 2,000 g for ceous material. We then needed to devise a one hour. The sediment, consisting of crude procedure for counting the fibers so as to obtain reproducible results. We also found it necessary to modify our previously pub lished method for isolating ferruginous bodies from the lung6] in order to obtain quantitative yields. In this paper, we are reporting the details of these methods, as well as the results obtained on the lungs of a small number (seven) of urban dwellers (se impure dust, was collected into a single flask and washed three to four times with 160-ml portions of warm formamide. The sediment was submitted to further digestion with 200 ml of formamide for 24 hours, and it was then washed with 160-ml portions of the following warm solvents: formamide; formamide-water (1:1); water; methanol; methanol-chloToform (3:2); chloroform-hexane (2:8); and n-hexane. The sediment was kept in contact with each of lected only in respect to sex), of a long-time the solvents successively under continuous stir employee of an asbestos products factory, ring at least for two hours and was repeatedly and of two men who had been exposed for a working lifetime to dust in a factory produc ing fibrous glass. (From a factory which pioneered the production of fibrous glass, we have on hand for detailed study the lungs of 16 long-time employees who had died of natural causes. The above two workers are the first and second on which data have become available.) washed with several portions of each solvent until the washings were clear and colorless. It was finally dispersed in a small volume of hexane, vacuum dried at 60 C for 24 hours, and weighed. Separation of Naked Fibers From Dust-- Ten milligrams of the isolated dust was sus pended in 6 ml of 70% perchloric acid and heated in a sand bath at 160 to 180 C until the carbonaceous material disappeared (about 30 Arch Environ Health--Vof 21, July 1970 8005 1429 PRODUCED BY FORD