| Project/Area Number |
09558064
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Nuclear fusion studies
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
KOMATSU Kenshi Research Institute for Radiation Biology and Medicine, Hiroshima University, Professor, 原爆放射能医学研究所, 教授 (80124577)
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| Co-Investigator(Kenkyū-buntansha) |
TAUCHI Hiroshi Research Institute for Radiation Biology and Medicine, Hiroshima University, Ass, 原爆放射能医学研究所, 助手 (70216597)
MATSUURA Shinya Research Institute for Radiation Biology and Medicine, Hiroshima University, Ass, 原爆放射能医学研究所, 助手 (90274133)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥11,800,000 (Direct Cost: ¥11,800,000)
Fiscal Year 1998: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1997: ¥9,900,000 (Direct Cost: ¥9,900,000)
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| Keywords | a human X-chromosome / gene mutation / 6-thioguanin resistance / tritium / hybrid cells / HPRT mutation / ionizing radiation / RBE / ハイブリッド細胞 / 6-チオグアニン / 電離放射線 / HPRT / Cu炭素粒子線 / 遺伝子突然変異 / 染色体移入 / hprt遺伝子 / 放射線感受性 / 遺伝的影響 / ホルミ-シス効果 |
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| Research Abstract |
HPRT mutation was used to assay the radiation effect, since it is possible to isolate by positeve-negative selection with 6-thioguanin and HAT (hypoxunthin-aminopterin-thymidine). Howeverr, radiation is known frequantly to induce DNA-deletion type mutation, which possibly decrease the HPRT mutation rate. To detect the deletion mutation, we developped HPRT deficient hamster-based hybrid cells, where an intanct human X-chromosome. was transfered our experiments showed that appropriate expression time of these cells is 8-10 days after irradiation. The mutation incidence of theses cells was 450 mutants/ 10^5 survived cells after 4-Gy irradiation and it was contrast with mutantion rate in conventional rodent assay system : 5-50 mutants/10^5 survived cells. Thus, newly developped assay system indicated 10-100 fold highre sesnsitivity than that used to assay for radiation effect. Existance of a transferred human chromosome in their mutant cells were confirmed by FISH ana1ysis, implying mutation induction with the of HPRT gene. Mutation incidences were linearly increased with radiation dose of ^<60>Co-gamma-rays and this dose-relationship showed the approxinately 100-fold high sensitivity, compared with that of conventional HPRT mutation assay. When this incidence was compared with that of tritium-beta rays, the biological effectiveness RBE indicated the consistent value, 1.24, with previous observation. As a results, our studies demonstrated the high sensitivity and usefulness of hamster hybrid cells cantaining an intact human X-chromosome for evaluation of tritium biological effects.
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