| Project/Area Number |
06671886
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
病態科学系歯学(含放射線系歯学)
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
NAITO Kumiko HIROSHIMA UNIVERSITY,SCHOOL OF DENTISTRY,RESEARCH ASSOCIATE, 歯学部, 助手 (10155632)
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| Co-Investigator(Kenkyū-buntansha) |
SUEI Yoshikazu HIROSHIMA UNIVERSITY,SCHOOL OF DENTISTRY,RESEARCH ASSOCIATE, 歯学部, 助手 (10206378)
YAMADA Toshikazu HIROSHIMA UNIVERSITY,SCHOOL OF DENTISTRY,RESEARCH ASSOCIATE, 歯学部・附属病院, 助手 (10263724)
和田 卓郎 広島大学, 歯学部, 教授 (10028756)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1995: ¥900,000 (Direct Cost: ¥900,000)
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| Keywords | LX830 cells / L5178Y cells / Thermal radiosensitization / Thermosensivitiy |
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| Research Abstract |
Using the colony formation method, survival response to heat and/or irradiation was examined in two cell lines with equal thermosensitivity, L5178Y cell and its radiosensitive mutant LX830 cell.
Although it is considered that thermal radiosensitization varies depending on radiosensitivity of each cell line, thermal radiosensitization was same in both cell line when both cell line were received heat treatment which cause 50% survival rate. To clarify the reason why two cell lines with different radiosensitization showed same thermal radiosensitization, we made experiments about the cell cycle, sublethal and potentially lethal damage repair.
Ratio of cell distribution in each cell cycle phase was same. Most cells were in G_1 phase and showed same thermosensitivity in its phase. Sublethal damage repair also showed same capacity, but potentially lethal damage repair was observed only in L5178Y cells. These result suggested that heat radiosensitization is caused by an interference of sublethal damage repair. Further, it was also indicated that thermal radiosensitization is closely dependent not only on the radiosensitivity but on thermosensitivity.
During thermotolrant state, the minimum heat radiosensitization showed in the maximum thermotolerant stage of both cell lines. This result suggests that the mechanisum of thermotolerance may be connected with the mechanisum of heat radiosensitization.
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