subject: Exposure to Pulmonary Carcinogens and Mesothelioma [print this page] When pieces of asbestos are inhaled or swallowed, they can lead to life threatening diseases. To date, over 730,000 people have filed claims for asbestos related injuries in the United States alone. One interesting study that examples the link between exposure and Mesothelioma disease is called, "Analysis of asbestos fibers and asbestos bodies in tissue samples from human lung. An international interlaboratory trial." by Gylseth B, Churg A, Davis J.M., Johnson N, Morgan A, Mowe G, Rogers A, Roggli V. - Scand J Work Environ Health. 1985 Apr;11(2):107-10. Here is an excerpt: "Abstract - In order to compare methods of counting asbestos fibers in lung tissue, seven laboratories participated in an interlaboratory trial in which tissue samples from five human lungs were analyzed. In some laboratories, fiber concentrations were assessed with the light microscope and, in others, with either scanning or transmission electron microscopes. Within each laboratory the ranking of the results was similar, but there were marked differences in the absolute values obtained by the different laboratories. It is concluded that the laboratories participating in this trial appear to produce internally consistent results, but there is difficulty in directly comparing results from one laboratory to the next."
A second study is called, "Reduced Fhit protein expression and loss of heterozygosity at FHIT gene in tumours from smoking and asbestos-exposed lung cancer patients." By Pylkkanen L, Wolff H, Stjernvall T, Tuominen P, Sioris T, Karjalainen A, Anttila S, Husgafvel-Pursiainen K. Int J Oncol. 2002 Feb;20(2):285-90. Here is an excerpt: "Abstract - The FHIT gene, at 3p14.2, has been suggested to form a molecular target to damage induced by human lung carcinogens. We examined aberrant expression of the Fhit protein and allele loss at the FHIT gene in a series of lung cancer cases, mainly of non-small cell carcinoma (NSCLC) histology. We had detailed data on tobacco smoke exposure and occupational asbestos exposure available for the cases. The principal aim of the present study was to investigate whether absent or reduced Fhit expression or FHIT allele loss was associated with exposure to these pulmonary carcinogens. We detected reduced Fhit expression in 62% (33/53) of the cases analysed. Prevalence of allele loss at the FHIT locus was 22% (20/89). Reduced protein expression was common both in the asbestos-exposed (67%) and non-exposed cases (59%); [odds ratio (OR) 1.4, 95% confidence interval (CI) 0.4-4.9]. LOH frequencies differed somewhat between the two groups and were 25% vs. 16%, respectively (OR 1.8; 95% CI 0.5-5.9). Absent or reduced expression was common in smokers, with no significant difference found between current smokers and non-smokers (mainly former smokers) (OR 1.4, 95% CI 0.5-4.5). NSCLCs with squamous cell histology exhibited both aberrant [removed]OR 3.1, 95% CI 0.9-10.3) and allele loss (OR 3.3, 95% CI 0.9-12.7) more frequently than adenocarcinoma. Finally, we found that FHIT allele loss was increased in stage II or more advanced disease (OR 2.5, 95% CI 0.9-7.4), and in poorly differentiated tumours (grade 3, OR 2.6, 95% CI 0.8-8.1). In conclusion, our present data support significance of FHIT inactivation in development of lung cancer."
A third study is called, "Effects of crocidolite and chrysotile asbestos on cellular uptake and metabolism of benzo(a)pyrene in hamster tracheal epithelial cells." Environ Health Perspect. 1983 September; 51: 331 by B. T. Mossman, A. Eastman, J. M. Landesman, and E. Bresnick. Here is an excerpt: "Abstract - The incidence of bronchogenic carcinoma is increased substantially in asbestos workers who smoke. We used several approaches to determine possible mechanisms of synergism at the cellular level between asbestos and the polycyclic aromatic hydrocarbon (PAH), benzo(a)pyrene (BaP), a chemical carcinogen in cigarette smoke. Specifically, we hypothesized that cellular uptake and metabolism of BaP might be facilitated when the hydrocarbon was coated on asbestos. In addition, we were interested in whether asbestos, alone or in combination with BaP, caused single strand breakage of DNA in epithelial cells of the airway. UICC reference samples of crocidolite and chrysotile were coated with 3H-BaP before their addition to monolayers of hamster tracheal epithelial cells. In comparative studies, 3H-BaP at identical amounts was added to cells in culture medium. At intervals thereafter, uptake of BaP by cells was documented by scintillation spectrometry and by autoradiography. In addition, cells and media were assayed by use of high pressure liquid chromatography (HPLC) to demonstrate the water-soluble metabolites of BaP. The integrity of DNA was monitored by alkaline elution at intervals after exposure of tracheal cells to various concentrations of asbestos, BaP and BaP-coated asbestos. A rapid transfer of BaP to cells occurred after addition of BaP-coated asbestos to cultures. When BaP was adsorbed to both types of fibers before their addition to cultures, 70% of the total BaP introduced entered the cell within 1 hr; 50% remained intracellular after 8 hr."
If you found any of these studies interesting, please read them in their entirety. We all owe a great deal of thanks to the people who are researching these important issues.
Exposure to Pulmonary Carcinogens and Mesothelioma
By: Montwrobleski77
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