| Co-Investigator(Kenkyū-buntansha) |
TOYA Kazuhito KEIO University School of Medicine Asistant, 医学部, 助手 (30265912)
KAWADA Tetsuya KEIO University School of Medicine Asistant, 医学部, 助手 (60234077)
KUTSUKI Shouji KEIO University School of Medicine Asistant, 医学部, 助手 (00234443)
NAKAYAMA Toshitake KEIO University School of Medicine Asistant, 医学部, 助手 (90189077)
ITO Hisao KEIO University School of Medicine Professor, 医学部, 教授 (20095574)
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| Budget Amount *help |
¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1997: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1996: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
In order to evaluate the biological effectsu of heavy-ion beams and X-rays on cultured cells, we investigated the cell-killing effects and mutation induction at the hprt locus, at first. The cell-lines we used were Chinese hamster origin (V79), human ovarian cancer origin (RMG1), human breast cancer origin (MDA-MB231) and human esophageal cancer origine (TE24). Cells were cultured in monolayr condition and irradiated by X-rays (150kVp) or carbon beams (20keV/mu m, 80keV/mu m) or neon beam (80keV/mu m), and cell survivals were calculated by colony assay and the mutation frequencies at hprt locus were calculated from the numbers of colonies formed in media supplemented with 6-thioguanin. We obtained the following results at least in three cell lines (V79, RMG1 and MDA-MB231). (1) the heavy ion beams showed much more powerful cell-killing effects than X-rays and carbon beams with high LET showed more enhanced effects than low LET beams, (2) when the same LET level was used, carbon beam sh
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owed slightly higher cell-killing effect compared with neon beam, (3) extremely higher mutation frequency was observed for cells irradiated by the heavy ion beams compared with that irradiated by X-rays, (4) the mutation frequency was increased when the LET of carbon beam was increased, (5) the mutation frequency was less for neon than carbon when the same LET level was employed. We are getting almost the same results with TE24, but still more experiments will be needed with this cell-line.
We also tried to evaluate the frequencies of apoptotic cells for these four cell-lines after irradiation by X-rays and heavy ion beams. Apoptotic cells were detected by Apo2.7 monoclonal antibody using the flow-cytometer. Apo2.7 is a PE labeled monoclonal antibody for the 7A6 antigen (protain of 38kD) which is appeared for the mitochondria membrain of apoptotic cells from eary stage of apoptosis. The detection ability of this method for the apoptotic cells were so sensitive that it was very difficult to get the best condition of experiment for each cell-line. This time, we could clearfy the indispensable condition of this nethod for these cell-lines irradiated by X-rays. We will analyze the frequencies of apoptotic cells after heavy ion beam irradiation under the obtained condition, and investigate the relationship with the cell-killing effects and the mutation induction effects. Less
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