tremolite and Peritoneal-Neoplasms

The aim of the study was to reanalyze an updated database of lung asbestos fiber levels for 21 brake repair workers who died of mesothelioma using robust maximum likelihood-based regression methods to address nondetectable measurements.. We applied bivariate normal regression to address the doubly left-censored situation where both the lung fiber concentration of noncommercial (TAA) and commercial amphiboles (AC) were subject to detection limits. For the single left-censored situation, we applied censored normal regression to study the relationship between duration of employment (DOE) and TAA.. We found a statistically significant positive relationship between TAA and AC (β = 0.49, 95% confidence interval [CI], 0.11 to 0.86) and a not statistically significant relationship between DOE and TAA (β = 0.02, 95% CI, -0.03 to 0.06).. Our results provide additional support for the conclusion that exposure to commercial amphibole asbestos, and not chrysotile, is related to the occurrence of mesothelioma among some brake workers.

Topics: Adult; Aged; Asbestos, Amphibole; Automobiles; Humans; Limit of Detection; Lung; Maintenance; Mesothelioma; Middle Aged; Occupational Diseases; Occupational Exposure; Peritoneal Neoplasms; Pleural Neoplasms; Regression Analysis

Tremolite contamination has been proposed as the cause of mesothelioma in workers exposed to commercial chrysotile. The asbestos industry and scientists it has sponsored, for example, have argued that commercial chrysotile does not cause peritoneal mesothelioma.. Case report of peritoneal mesothelioma in a mill worker from a tremolite free Canadian mine.. Reports from pathology and occupational health and safety panels conclude that this mill worker developed work-related peritoneal mesothelioma.. Chrysotile without tremolite can cause peritoneal mesothelioma.

Topics: Aged; Asbestos, Amphibole; Asbestos, Serpentine; Fatal Outcome; Humans; Male; Mesothelioma; Occupational Diseases; Occupational Exposure; Peritoneal Neoplasms; Quebec

The high incidence of malignant mesothelioma in some villages of Cappadocia (Turkey) is due to environmental exposure to erionite fibres. The aim was to evaluate the fibre burden in bronchoalveolar lavage fluid (BALF) from inhabitants of an erionite village and compare it with Turkish subjects with or without environmental exposure to tremolite asbestos.. Ferruginous bodies (FBs) and fibres were measured and analyzed by light and transmission electron microscopy (TEM) in the BALF of 16 subjects originating from Tuzköy.. FBs were detected in the BALF of 12 subjects, with concentrations above 1 FB/ml in seven of them. Erionite was the central fibre of 95.7% of FBs. Erionite fibres were found in the BALF of all subjects, by TEM, and these fibres were low in Mg, K, and Ca compared with erionite from Tuzköy soil. The mean concentration of erionite fibres in BALF was similar to that of tremolite fibres in Turks with environmental exposure to tremolite. The proportion of fibres longer than 8 microm in BALF represented 35.6% for erionite compared with 14.0% for tremolite. The asbestos fibre concentrations in erionite villagers was not different from that in Turks without environmental exposure to tremolite.. Analysis of BALF gives information about fibre retention in populations environmentally exposed to erionite for whom data on fibre burden from lung tissue samples are scarce. This may apply to exposed Turks having emigrated to other countries.

Topics: Adult; Asbestos, Amphibole; Body Burden; Bronchoalveolar Lavage Fluid; Case-Control Studies; Environmental Exposure; Female; Humans; Male; Mesothelioma; Microscopy, Electron; Middle Aged; Mineral Fibers; Peritoneal Neoplasms; Pleural Neoplasms; Soil Pollutants; Turkey; Zeolites

About 8% of our cases of mesothelioma occur in women, with a median age of 59 years. Our percentage is lower than other series reported in the literature because of the large number of occupationally exposed men referred to our laboratory. Tumor arose in the pleura in 86% of the women in our study, and the majority were epithelial. Pleural plaques were found in half of the women for which this information was available, and asbestosis was found in only 16%. A history of exposure to asbestos was identified in three quarters of the women, more than half of whom were household contacts of asbestos workers. Occupational exposure to asbestos was identified in only 19% of patients. An elevated tissue asbestos burden was noted in 70% of women from whom lung tissue was available for analysis. The main fiber type identified was amosite, followed by tremolite and chrysotile. These findings and those from other countries suggest a need for reassessment of the background rate of mesothelioma in industrialized nations.

Topics: Adult; Aged; Aged, 80 and over; Asbestos, Amosite; Asbestos, Amphibole; Asbestos, Serpentine; Asbestosis; Female; Humans; Male; Mesothelioma; Middle Aged; Mineral Fibers; Peritoneal Neoplasms; Peritoneum; Pleura; Pleural Neoplasms

We describe a case of malignant peritoneal mesothelioma arising in a 17-year-old boy. The diagnosis was based on a comprehensive study including light microscopy, histochemistry, immunohistochemistry, evaluation of the clinical course, and autopsy examination. Analytical transmission electron microscopy showed a concentration of 510,000 asbestos fibers/g dry lung tissue. The fibers were represented by chrysotile (62%) and tremolite (38%) asbestos. About 40% of the total fibers were longer than 5 microns. The presence of tremolite fibers was probably due to environmental exposure to contaminated cosmetic talc. This is the first reported case of pathologically proven exposure to asbestos dust in malignant mesothelioma of childhood and adolescence.

Topics: Adolescent; Asbestos, Amphibole; Asbestos, Serpentine; Autopsy; Humans; Male; Mesothelioma; Peritoneal Neoplasms

Six samples of tremolite of different morphological type were prepared as dusts of respirable size and used in intraperitoneal injection studies in rats. Three "asbestiform" tremolites produced mesotheliomas in almost all animals, although with significantly different tumor-induction periods. A brittle type of fibrous tremolite which, when manipulated to prepare "respirable dust," produced a sample with relatively few asbestiform fibers remaining nonetheless produced tumors in 70% of rats. Two samples of nonfibrous tremolite produced respirable dust samples containing numerous elongated fragments with aspect ratios greater than 3:1, which therefore fitted the definition of respirable fibers. Both these samples produced relatively few tumors, although one had more long "fibers" than did the brittle tremolite that produced 70% of tumors. This study has therefore demonstrated that different morphologic forms of tremolite produce dusts with very different carcinogenic potential. Carcinogenicity does not depend simply on the number of elongated particles injected, and we need to develop methods of distinguishing carcinogenic tremolite fibers from relatively innocuous tremolite dusts, with similar numbers of elongated particles of similar aspect ratios.

Topics: Animals; Asbestos, Amphibole; Carcinogens; Dust; Injections, Intraperitoneal; Mesothelioma; Particle Size; Peritoneal Neoplasms; Rats; Silicic Acid

Topics: Aluminum Silicates; Asbestos; Asbestos, Amphibole; Asbestos, Serpentine; Environmental Exposure; Female; Humans; Male; Mesothelioma; Middle Aged; Minerals; Occupational Diseases; Peritoneal Neoplasms; Pleural Neoplasms; Time Factors; Zeolites