Asbestos content of omentum and mesentery in nonoccupationally exposed individuals.

Asbestos fibers in occupationally exposed individuals relocate from the lung to extrapulmonary sites. A mechanism for relocation is via the lymphatic circulation. Indeed, asbestos fibers have been found in lymph nodes as well as pleural plaques. Our laboratory has recently shown that asbestos fibers also reach the mesentery and omentum in the peritoneal area where a small percentage of mesotheliomas occurs in exposed individuals. The present study uses light and analytical transmission electron microscopy for defining the asbestos burden in digested lung, omentum, and mesentery tissues from individuals considered as representing the general population in East Texas. The findings, when compared with previous data from occupationally exposed individuals, indicate extreme contrasts as to the level and types of fiber burden between individuals representing the groups.

Asbestos content in the lymph nodes of nonoccupationally exposed individuals.

BACKGROUND: The thoracic lymph nodes are a part of the clearance system from lung tissue. Accumulation of dust in these nodes are known to occur following some types of exposure. However, no information exists as to asbestos content in lymph nodes from the general population. METHODS: The study cohort consisted of 21 individuals previously defined as nonoccupationally exposed to asbestos. Tissue burden of asbestos obtained from lung analysis by analytical electron microscopy was compared with burden in the lymph nodes. RESULTS: No asbestos fibers were detected in nodes from 8 cases. The majority of the fibers found in lymph nodes were short (<5 microm) and most often noncommercial amphiboles. Ferruginous bodies (FBs) were detected in lymph node from only two samples. CONCLUSIONS: The total asbestos burden in the lung tissue from these individuals was quite low. However, in 12 of the 13 cases that had positive nodes, the tissue burden in the node was appreciably heavier per gram than in the lung. This raises the question as to whether the lymph nodes, though less efficient clearance, may be better indicators of lifetime exposure to dust than lung tissue.

Tissue burden of asbestos in nonoccupationally exposed individuals from east Texas.

BACKGROUND: The potential for asbestos exposure among members of the general population is appreciable, considering its widespread use in many products. This study examined tissue burden of asbestos in such a population. METHODS: A group of 33 individuals who had no work history of occupational exposure to asbestos were included in the study. Tissue sections from areas adjacent to those sites sampled for digestion were found to be without ferruginous bodies (FB) or histopathology consistent with asbestos-induced changes. All individuals had 20 or less FBs per gram of digested wet lung, a number considered to reflect general population levels. Tissue analysis of uncoated fiber burden was carried out by analytical electron microscopy. There was a trend of a higher likelihood of FB and asbestos fiber content correlated with age. RESULTS: The data are not consistent with the findings that chrysotile is readily found in lung tissue from the general population, in that none was found in 19 of the cases. It was almost as likely that one would find anthophyllite (12 of 33 cases) in this study. The commercial amphiboles (amosite and crocidolite) were occasionally found in the tissue from the general population and, when observed, were few in numbers. Twenty-six of the patients had no FBs and ten had no uncoated asbestos fibers within the limits of detectability in this study. CONCLUSIONS: The total tissue burden of asbestos in this study is much less than earlier reported observations from other general populations.

Lack of asbestos contamination of paraffin.

OBJECTIVE: To investigate possible asbestos contamination of paraffin and migration by asbestos fibers during the tissue-embedding process. DESIGN: Three sample categories were included in the study: (1) commercially available paraffin samples; (2) procedural control samples, which were prepared by processing the paraffin through the use of standard solvents and instruments; and (3) samples taken from areas adjacent to embedded tissue and evaluated for migration of asbestos from the tissue into the surrounding paraffin. The analysis of collected material from all samples was performed with analytical transmission electron microscopy. RESULTS: Only one extremely small tremolite fiber was found in any of the commercially available samples of paraffin. No asbestos fibers were found either in the procedural control samples or in the samples taken adjacent to the embedded lung tissue. CONCLUSIONS: First, it was extremely unlikely that any of the commercial paraffin samples would have skewed data due to embedded tissue. Second, the processing and instrumentation was not found to contribute asbestos material to the paraffin during the preparations. Finally, embedded tissue that contained high numbers of fibers, both uncoated fibers and asbestos bodies, did not contribute asbestos to the adjacent paraffin.