| Project/Area Number |
12670885
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Radiation science
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| Research Institution | Nagasaki University |
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Principal Investigator |
OKUMURA Yutaka School of Medicine, Dept. of Radiat. Biophys., Professor, 医学部, 教授 (00073130)
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| Co-Investigator(Kenkyū-buntansha) |
TAKESHITA Satoshi Joint Research Center, Associate Professor, 地域共同研究センター, 助教授 (20295083)
IHARA Makoto School of Medicine, Dept. of Radiat. Biophys., Senior Scientist, 医学部, 助手 (60175213)
岡市 協生 長崎大学, 医学部, 助教授 (80124874)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2001: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2000: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | scid cells / radiosensitivity / heavy ion particles / DNA double strand breaks / DNA-PK activity / RBE / DNA二重鎖切断 |
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| Research Abstract |
Scid cells deficient in DNA-PK are highly sensitive to low LET radiations as well as high LET radiations. Hybrid scid cells introduced by a fragment of human chromosome 8 which contains the structural gene of DNA-PK recover radiosensitivity to the level of wild parental cells. In this study, changes in radiosensitivity of scid cells to high LET radiation, heavy ion particles, was investigated in order to elucidate the process how DNA damages induced by LET radiation were repaired.
X-rays (200 kV) and carbon ions as heavy ion particles (290MeV/u, 50 keV/μm) for high LET radiation were used. Changes in radiosensitivity by heat treatment in scid cells and hybrid scid cells irradiated with high LET radiation were investigated. Although both cell lines showed radiosensitization when heat treatment was combined, scid cells were more sensitized than scid hybrid cells. This result showed that other DNA repair systems exist in scid cells, which might be heat sensitive.
Wortmannin, an inhibitor of phosphorylation to PI3 kinase family, was treated with high LET irradiation. Ratio of radiosensitivity was increased when wortmannin was combined with irradiation in both cell lines. The enhancement ratio of radiosensitivity by applying wortmannin was the same for low and high LET irradiation, and was 2.5-3.1 and 1.3 -1.4 for scid hybrid cells and scid cells respectively.
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