量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum and Radiological Science and Technology.
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Exposure to low priming doses of ionizing radiation is known to decrease the biological effects of a subsequent higher challenging dose. This adaptive response (AR) to low dose radiation was described in a variety of models, using various endpoints. In this study, we investigated the ability of low doses of X-rays to induce an AR to the biological effects of high-LET heavy-ion radiation (carbon-ion, neon-ion, 20 to 150 keV.um-1), in cultured human lymphoblastoid cells TK6 (p53 +/+) and AHH-1 (p53 +/-). We observed that cells adapted by X-rays showed a reduced mutation frequency at HPRT locus after exposure to high-LET radiation at HIMAC (NIRS, Chiba, Japan). AR in our model was dependent on p53 status but linked to neither cell cycle effects nor modulation of radiation-induced apoptosis. The analysis of H2AX phosphorylation kinetics in adapted and non adapted cells suggested that modulation of DNA double-strand break repair activity may be involved in this phenomenon. Knowing that high-LET radiation produces non-randomly distributed DNA damage in the form of clusters, or locally multiply damaged sites (LMDS), it seems that triggering AR by exposing cells to low doses of ionizing radiation could protect cells against the detrimental effects of such damage
Mutagenic adaptive response in human lymphoblastoid cells exposed to low and high-LET radiation
