@misc{oai:repo.qst.go.jp:00080773,
 author = {平嵜, 敬志朗 and 小畑, 結衣 and 横谷, 明徳 and Hirasaki, Keishiro and Obata, Yui and Yokoya, Akinari},
 month = {Oct},
 note = {Studies using in vitro analysis reported that yields of the clustered DNA damage consisting base lesions, AP sites, or single-strand breaks increased with increasing level of hydration. Energy deposition pattern of ionizing irradiations to the DNA hydration network is obviously a key factor to determine the localization of lesions. So far, little evidence has supported the idea that the radiation induced cluster damage inhibits cellular repair activities. We developed an ex vivo procedure to analyze the reparability in cells using an EGFP-expressing plasmid. This method visualizes repairability of damage as an EGFP expression rate by transfection of the plasmids into non-irradiated mammalian cells. In the present study, we applied this method to investigate correlation between damage complexity and reparability in cells. The plasmids were exposed to X-rays in a Tris-EDTA buffer solution or fully hydrated films containing 35 water molecules per nucleotide. The absorbed dose gave the plasmid average one single-strand break according to Poisson statistics, i.e. the dose giving 37% (1/e) of a residual intact closed circular fraction of the plasmid. The irradiated plasmids were then transfected into non-irradiated human cells (MCF-7). EGFP expression in cells was observed for 48h with a fluorescence microscope. The repair rates were determined from the slops of the EGFP expression kinetics. Preliminary results showed that the efficiency for the hydrated plasmid films was lower than that for the solution sample. Hydration waters would contribute to complexity of DNA damage which might be less repairable rather than those by water radiolysis radicals., 日本放射線影響学会第63回大会},
 title = {Live cell imaging of repair of EGFP plasmid DNA damage induced by X-ray energy deposition on hydrated waters},
 year = {2020}
}