1992 Fiscal Year Final Research Report Summary
Experimental Studies on the Carcinogenicity of Man Made Fibers
| Project/Area Number |
02454214
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
公衆衛生学
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| Research Institution | Saitama Medical School |
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Principal Investigator |
ADACHI Shuichi Saitama Medical School, Dept. Public Health, Lecturer., 医学部, 講師 (90129148)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAMURA Ken Saitama Medical School, Dept. Public Health, Research assoc., 医学部, 助手 (60204773)
TAKEMOTO Kazuo Saitama Medical School, Dept. Public Health, Professor, 医学部, 教授 (50049764)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Man made fiber / Asbestos / Carcinogenicity / Mesothelioma / Lung cancer / Radical / DNA damage / 8-Hydroxyguanine |
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| Research Abstract |
Histological observations were performed on female Syrian hamsters two years after the intratracheal administration of amphibole asbestos, amosite and crocidolite, to evaluate the tumorigenicity of six types of fine man-made fibers. It was demonstrated that some type of man-made fibers had a potency to induce tumors much more than asbestos. Moreover, as a specific observation in man-made fiber groups, tumors were induced at intracelial organs rather than at the pleural cavity. It was suggested that the thickening of visceral pleura might be induced by a different mechanism from the tumorigenicity of fibrous materials, since there was no relation between the pleural thickening and mesothelioma incidence in hamsters.
We compared the potential of asbestos and man-made fibers to attack DNA by the determination of the yield of 8-hydroxy-2'-deoxyguanosine (oh^8dG) in several conditions in vitro. It was suggested by the result that asbestos could damage DNA which resulted in oh^8dG as a cause of point mutation and also several types of man-made fibers had similar effects as asbestos under certain conditions.
Rats(Wistar, female, 4 week-old) were fed iron-deficient or manganese and copper-deficient diets for 8 weeks to determine the oxidative damage of DNA in element deficiency. Results suggest that the risk of cancer may be associated with the minor and essential element intake. We also determined the amount of oh^8dG in the nuclear DNA of regenerating liver (24, 48, 72 hours and 7 days after partial hepatectomy) of male Sprague Dawley rats exposed to 2-nitropropane for the verification of a hypothesis that a high sensitivity to carcinogens after partial hepatectomy is responsible for the sensitivity of DNA damage in the cell proliferating stage. It is suggested that nuclearDNA in a proliferating cells, e.g., cells in continuous cell damage by fibrous materials, is in a sensitive stage to exogenous attack by active oxygen species.
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