@misc{oai:repo.qst.go.jp:00060495,
 author = {Okayasu, Ryuichi and Okada, Maki and Okabe, Atsushi and Takakura, Kaoru and 岡安 隆一 and 岡田 真希 and 岡部 篤史 and 高倉 かほる},
 month = {Jul},
 note = {We studied the repair process of G0 or G1 phase normal (HFL III) and non homologous end joining (NHEJ) deficient human fibroblasts (180 BR) exposed to X-rays and high LET carbon ions (70 keV per micro m) using a modified fusion-based premature chromosome condensation (PCC) technique. We have succeeded in increasing the sensitivity of the PCC method by adding a potent DNA double strand break repair inhibitor, wortmannin, during the incubation period of this assay. With x-ray exposure (2 Gy or less), the rejoining of G1 chromosome breaks in 180BR cells are significantly slower and less efficient than that in normal cells. On the other hand, the difference in rejoining kinetics between 180 BR and normal cells with high LET carbon exposure is much smaller than that with x-ray exposure. These results seem to reflect the radiation cell survival responses using the same cell lines. We also studied the auto-phosphorylation status of DNA dependent protein kinase catalytic subunit (DNA-PKcs) protein in cells exposed to high and low LET radiation. Our immuno-staining results using an antibody to detect an auto-phosphorylation site of DNA-PKcs further reveal the difficulty in NHEJ for cells exposed to high LET radiation. The peak time for the auto-phosphorylation in x-irradiated normal human cells is one hour post-irradiation, but the peak in the same cells irradiated with high LET carbon beams shifted to two hours post-irradiation, reflecting much slower NHEJ processing associated with the high LET radiation. These data help understand the mechanism underlying the biological effect induced by heavy ion particles in the space environment., 35th COSPAR Scientific Asembly},
 title = {CHARACTERISTIC STUDIES OF NON-HOMOLOGOUS END JOINING IN HUMAN CELLS IRRADIATED WITH HIGH LET RADIATION},
 year = {2004}
}