| Project/Area Number |
09670908
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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 | HIROSAKI UNIVERSITY |
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Principal Investigator |
ABE Yoshinao SCHOOL OF MEDICINE PROFESSOR, 医学部, 教授 (10167950)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUTANI Hideya SCHOOL OF MEDICINE RESEARCH ASSISTANT, 医学部, 助手 (30241483)
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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 |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1998: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1997: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | JEJUNAL CRYPT / FRACTIONATION / REPOPULATION / CELL LOSS FACTOR / APOPTOSIS / POTENTIAL DOUBLING TIME / MULTIPLE FRACTIONS A DAY / PROLIFEARTIVE RESPONSE / 小腸線窩 / 3H-チミジン / 移行時間 |
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| Research Abstract |
To improve the efficacy of radiation therapy, the cause of radioresistance due to tumor repopulation during fractionation should be solved. Through these fiscal years of 1997-1998, we obtained the following experimental data regarding proliferative responses during fractionation in murine jejunal crypt. Through the experiments, fraction (fx) size was 2 Gy. 1) Clonogenic cells in the crypt were rapidly repopulating during fractionation and the extent of repopulation was dependent on fraction size a day : 2-fx-a-day treatment induced more than 1-fx-a-day treatment. 2) Number of cells in the crypt increased significantly during 2-ft-a-day treatment compared with 1-fx-a-day treatment. 3) Both treatments caused faster potential doubling time (Tpot) during fractionation and did not vary the Tpot. 4) Transition time from crypt to villi showed slower during 2-fx- a-day treatment than 1-ft-a-day treatment ; i.e. decreased cell loss factor. 5) Number of apoptosis was more increased during 2-fx-a-day treatment than 1-fx-a-day treatment.
To summarize these results, repopulation during fractionation inmurine jejunal crypt was observed and was dependent on the fraction number a day. Such proliferative responses increased the number of cells in the crypt and, thus, maintained the number of clonogenic cells in the crypt. Shortening of Tpot and decreased cell loss factor is the causes of repopulation during fractionation. These papaers are in prepare for publications.
Clinical data regarding repopulation were also reported inrelationship to such as overall treatment time, accelerated fractionation and DNA ploidy. Another clinical data suggesting importance in timing of chemotherapy during fractionations which caused an excellent results were also reported.
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