subject: Chrysotile Properties and the Mesothelioma Plague [print this page] Mesothelioma has taken the lives of thousands, and continued research is the only hope of finding a cure. One interesting study is called, "Variation of properties of chrysotile asbestos subjected to milling" by A. M. Langera; M. S. Wolffa; A. N. Rohla; and I. J. Selikoffa - a Environmental Sciences Laboratory of the Department of Community Medicine, Mount Sinai School of Medicine, City University of New York, New York, New York - Journal of Toxicology and Environmental Health, Part A, Volume 4, Issue 1 1978 , pages 173 188. Here is an excerpt: "Abstract - Mechanical milling is commonly used to produce short chrysotile asbestos for experimental purposes. Such manipulation also decreases fiber crystallinity, alters Si-O and Mg-O interlayer bonding, induces coordination changes in the brucite layer, diminishes the ability of fiber to reduce specific free radicals and physisorb organic molecules, and decreases hemolytic potency and antagonist sorption capabilities. The degree of alteration is related to the time of milling. Results of biological experimentation with these materials must be interpreted with caution. Interaction mechanisms in the biological setting are suggested for chrysotile fiber."
Another interesting study is called, "Patterns of inflammation, cell proliferation, and related gene expression in lung after inhalation of chrysotile asbestos." By T. R. Quinlan, K. A. BruB, J. P. Marsh, Y. M. Janssen, P. Taishi, K. O. Leslie, D. Hemenway, P. T. O'Shaughnessy, P. Vacek, and B. T. Mossman - Am J Pathol. 1995 September; 147(3): 728739. Here is an excerpt: "Abstract - Biochemical and molecular markers of inflammation, cell proliferation, and pulmonary fibrosis were studied in lungs and bronchoalveolar lavage preparations from Fischer 344 rats at time periods from 3 to 20 days after inhalation of two airborne concentrations (0.18 and 8.2 mg/m3 air) of chrysotile asbestos. Additional groups of animals were examined for lung histopathology and cell proliferation with an antibody to 5-bromo-2'-deoxyuridine after exposure to asbestos for 5 and 20 days and after 20 days of exposure followed by an additional 20 days in room air. Exposure to chrysotile at the higher concentration caused protracted increases in steady-state mRNA levels of manganese-containing superoxide dismutase and elevation in glyceraldehyde-3-phosphate dehydrogenase mRNA at 3 days, but levels of mRNAs encoding copper-zinc-containing superoxide dismutase, ornithine decarboxylase, and the proto-oncogene, c-jun were not statistically elevated from levels occurring in lung homogenates from sham control rats. Differential cell counts in bronchoalveolar lavage revealed an early infiltration of neutrophils that correlated with focal areas of increased cellularity and fibrosis in rat lungs at the higher concentrations of asbestos. However, elevations in lung hydroxyproline were not observed. Significant increases in epithelial cells of the bronchi, the interstitial compartment of the lung, and mesothelial cells incorporating 5-bromo-2'-deoxyuridine, an indication of DNA synthesis, were noted in the higher chrysotile group at 5 days, but labeling in all cell compartments was comparable with that occurring in sham controls at later time points. Indicators of inflammation, increased cell proliferation, and pulmonary fibrosis were not observed in the lungs of rats exposed to the lower concentration of chrysotile. Thus, results indicate that cellular and molecular markers of inflammation and proliferation in lung are dose-related and indicative of the histopathological development of asbestosis."
A third study is called, "Malignant mesothelioma in south east England: clinicopathological experience of 272 cases." By D H Yates, B Corrin, P N Stidolph, K Browne - Thorax 1997;52:507-512. Here is an excerpt: "Abstract - BACKGROUND: Malignant mesothelioma is a rare pleural tumour associated with asbestos exposure. The proportion of malignant mesothelioma unrelated to asbestos exposure, and any differentiating features between exposed and unexposed cases, are not well described. This study describes occupational, clinical, and pathological features in a large cohort of cases of malignant mesothelioma from south east England. METHODS: All 272 cases from this region were studied, either in life or after death when necropsy examination suggested malignant mesothelioma. Detailed information was gathered regarding the occupational history, clinical course, and mode of death. Necropsies were performed in 98% of cases. Lung tissue was examined histologically to confirm the diagnosis, subtype of tumour, presence or absence of asbestosis and asbestos bodies. RESULTS: Exposure to asbestos was documented in 87% of cases, while in the remainder, no asbestos exposure was found nor were asbestos bodies seen; 94.5% were pleural, 5.1% peritoneal, and 0.4% pericardial. Right sided tumours were more common than left sided tumours (ratio 1.6:1). Patients usually presented with breathlessness and chest pain, but 33% presented with pleural effusion in the absence of chest pain. The mean (SD) time from first exposure to asbestos to symptoms was 40 (12) years with a median (interquartile range (IQR) survival of 14 (12.5) months. The median (IQR) survival time in sarcomatous, epithelial, and mixed cell type malignant mesothelioma was 9.4 (10) months, 12.5 (18) months, and 11 (14) months, respectively, and was significantly greater in cases detected by chance. Clinical features were similar in asbestos related and non-asbestos related malignant mesothelioma. CONCLUSIONS: In south east England most cases of malignant mesothelioma are associated with asbestos exposure. Clinical features do not differentiate between asbestos related and non-asbestos related disease."
We all owe a debt of gratitude to these fine researchers for their hard work and dedication. If you found any of these excerpts interesting, please read the studies in their entirety.
Chrysotile Properties and the Mesothelioma Plague
By: Montwrobleski77
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