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Takahashi, Akihisa*; Kubo, Makoto*; Igarashi, Chie*; Yoshida, Yukari*; Funayama, Tomoo; Kobayashi, Yasuhiko; Nakano, Takashi*
JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 82, 2015/03
DNA double-strand breaks (DSBs) induced by ionizing radiation pose a major threat to cell survival. The cell can respond to the presence of DSBs, through two major repair pathways: Homologous recombination (HR) and non-homologous end-joining (NHEJ). Higher levels of cell death are induced by high-LET radiation when compared to low-LET radiation, even at the same doses because of less effective or more inefficient DNA repair. In this study, we examine the effects of radiation with different LET values on DNA DSB repair and radiosensitivity. Wild-type cells and HR deficient (but NHEJ proficient) cells exhibited the high RBE values at LET values of 108 keV/
m. The RBE value for each cell type decreased with increasing LET values over 200 keV/m. Although NHEJ proficient cells had an almost constant SER value, NHEJ deficient cells showed a high SER value when compared to NHEJ proficient cells, even with increasing LET values.
Yokota, Yuichiro; Hase, Yoshihiro; Shikazono, Naoya; Tanaka, Atsushi; Inoue, Masayoshi*
International Journal of Radiation Biology, 79(8), p.681 - 685, 2003/08
Times Cited Count：21 Percentile：78.32(Biology)To determine the radiation sensitivity and the relationship between linear energy transfer (LET) and relative biological effectiveness (RBE) in single plant cells irradiated with heavy ions, single tobacco (BY-2) cells were irradiated with carbon ions (78.6 to 309 kev/m) and gamma rays (0.2 kev/m). Two weeks after the irradiation, colonies derived from the irradiated cells that had 16 cells or more were counted as survivors. The surviving fraction was fitted using the single-hit, multitarget theory. The dose needed to reduce the surviving fraction of the cells to 0.1 (D
) of gamma rays and carbon ions were 47.2 and 10.5 to 12.6 Gy, respectively. The radiation sensitivity of single tobacco cells was much lower than that of mammalian cells, although the mean number of base pairs per chromosome in the two cell types is similar. The RBE based on the D peaked at a LET of 247 keV/m. The RBE peak based on the D of carbon ions in single tobacco cells occurred at a higher LET than it dose in other organisms.
Ogura, K.*; Asano, Masaharu; Yasuda, Nakahiro*; Yoshida, Masaru
Nuclear Instruments and Methods in Physics Research B, 185(1-4), p.222 - 227, 2001/12
Times Cited Count：32 Percentile：88.93(Instruments & Instrumentation)no abstracts in English
Maezawa, Hiroshi*; Furusawa, Yoshiya*; Kobayashi, Katsumi*; Hieda, Kotaro*; Suzuki, Masao*; Usami, Noriko*; Yokoya, Akinari; Mori, Tomoyuki*
Acta Oncologica, 35(7), p.889 - 894, 1997/01
Times Cited Count：7 Percentile：22.9(Oncology)no abstracts in English
*; Ito, Hitoshi
Shokuhin Shosha, 30(1-2), p.11 - 16, 1995/00
no abstracts in English
Asano, Masaharu; Tamada, Masao; Yoshida, Masaru; Omichi, Hideki; Katakai, Ryoichi*; Vetter, J.*; Spohr, R.*
GSI 94-1, P. 204, 1994/03
no abstracts in English
Ito, Hitoshi; *; ; Sunaga, Hiromi; Ishigaki, Isao
Bokin Bobai-Shi, 19(4), p.161 - 166, 1991/00
no abstracts in English
*; Ito, Hitoshi; Ishigaki, Isao
Shokuhin Shosha, 26(1-2), p.47 - 50, 1991/00
no abstracts in English
-ray sensitivities of B.pumilus E601 spores; *; Ito, Hitoshi; Ishigaki, Isao
Shokuhin Shosha, 25(1-2), p.66 - 70, 1990/00
no abstracts in English
; ; *; Takehisa, Masaaki
Agricultural and Biological Chemistry, 47(5), p.1065 - 1069, 1983/00
no abstracts in English
; ; *
Shokuhin Shosha, 14, p.15 - 19, 1979/00
no abstracts in English
;
Hoken Butsuri, 8(4), p.229 - 236, 1973/04
no abstracts in English
Ouchi, Noriyuki
no journal, ,
Radiation sensitivity via cell survival shows cyclic radiation response, i.e. minimal when cells are irradiated in the early post-mitotic (G1) and the pre-mitotic (G2) phases of the cell cycle, and maximal in the mitotic (M) phase and late G1 or early synthesis (S) phases. Origin of the cell-cycle dependent radiation sensitivity is supposed to be a consequence of some intra-cellular dynamics, e.g. regulation mechanism of cell-cycle checkpoint, repair ability of DNA damage and higher order structure of chromosomes, no explicit theoretical explanation exists on this cyclic response yet. Here, cell-cycle dependent radiation sensitivity is studied from the viewpoints of dynamical aspects of chromosome in association with its cell-cycle dependent structural changes. For this purpose, dynamical model of chromosome is mathematically constructed based on the elastic nature of chromosomes and its radiation effects are simulated by introducing DNA double strand break (DSB) to the model.
Ouchi, Noriyuki
no journal, ,
no abstracts in English
