M M Finkelstein1, A Dufresne. 1. Ontario Ministry of Labour, Toronto, Canada. murray.finkelstein@utoronto.ca
Abstract
BACKGROUND: The health effects of asbestos are intimately related to the fate of inhaled fibers in the lungs. The kinetics of asbestos fibers have been studied primarily in rodents. The objective of this study was to explore the application of these kinetic models to human autopsy data. METHODS: We analyzed the asbestos fiber content of the lungs of 72 Quebec chrysotile miners and millers and 49 control subjects using analytical transmission electron microscopy. Statistical methods included standard multivariate linear regression and locally weighted regression methods. RESULTS: The lung burdens of asbestos bodies and chrysotile and tremolite fibers were correlated, as were the concentrations of short, medium, and long fibers of each asbestos variety. There were significant associations between the duration of occupational exposure and the burdens of chrysotile and tremolite. The concentration of chrysotile decreased with the time since last exposure but the concentration of tremolite did not. The clearance rate varied inversely with the length of chrysotile fibers. For fibers greater than 10 mu in length the clearance half-time was estimated to be 8 years. CONCLUSIONS: The patterns in our data are compatible with both of the hypotheses suggested from rodent experiments; the existence of a long-term sequestration compartment and overload of clearance mechanisms in this compartment.
BACKGROUND: The health effects of asbestos are intimately related to the fate of inhaled fibers in the lungs. The kinetics of asbestos fibers have been studied primarily in rodents. The objective of this study was to explore the application of these kinetic models to human autopsy data. METHODS: We analyzed the asbestos fiber content of the lungs of 72 Quebec chrysotile miners and millers and 49 control subjects using analytical transmission electron microscopy. Statistical methods included standard multivariate linear regression and locally weighted regression methods. RESULTS: The lung burdens of asbestos bodies and chrysotile and tremolite fibers were correlated, as were the concentrations of short, medium, and long fibers of each asbestos variety. There were significant associations between the duration of occupational exposure and the burdens of chrysotile and tremolite. The concentration of chrysotile decreased with the time since last exposure but the concentration of tremolite did not. The clearance rate varied inversely with the length of chrysotile fibers. For fibers greater than 10 mu in length the clearance half-time was estimated to be 8 years. CONCLUSIONS: The patterns in our data are compatible with both of the hypotheses suggested from rodent experiments; the existence of a long-term sequestration compartment and overload of clearance mechanisms in this compartment.
Authors: Mark Clements; Geoffrey Berry; Jill Shi; Sandra Ware; Deborah Yates; Anthony Johnson Journal: Occup Environ Med Date: 2007-04-20 Impact factor: 4.402
Authors: Michele Carbone; Shreya Kanodia; Ann Chao; Aubrey Miller; Anil Wali; David Weissman; Alex Adjei; Francine Baumann; Paolo Boffetta; Brenda Buck; Marc de Perrot; A Umran Dogan; Steve Gavett; Alessandro Gualtieri; Raffit Hassan; Mary Hesdorffer; Fred R Hirsch; David Larson; Weimin Mao; Scott Masten; Harvey I Pass; Julian Peto; Enrico Pira; Ian Steele; Anne Tsao; Gavitt Alida Woodard; Haining Yang; Shakun Malik Journal: J Thorac Oncol Date: 2016-08 Impact factor: 15.609