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Kobayashi, Yasuhiko; Funayama, Tomoo; Wada, Seiichi; Sakashita, Tetsuya
Uchu Seibutsu Kagaku, 18(3), p.186 - 187, 2004/11
no abstracts in English
Kobayashi, Yasuhiko; Kiguchi, Kenji*
Isotope News, (593), p.9 - 12, 2003/09
no abstracts in English
Kobayashi, Yasuhiko; Funayama, Tomoo
Isotope News, (590), p.2 - 7, 2003/06
A microbeam can be used for selective irradiation of individual cells, which can be subsequently observed to ascertain what changes occur to that cell and to neighboring un-irradiated cells. Therefore, the use of microbeam allows direct investigation of cell-to-cell communications such as "bystander effects", that is, radiation effects transmitted from irradiated cells to neighboring un-irradiated cells. Furthermore, a microbeam with sufficient spatial resolution will be useful for analyzing the dynamics of intra-cellular process such as apoptosis and the influence of track-structure of energetic heavy ions by means of highly localized irradiation of a part of a nucleus or cytoplasm.
Tu, Z.; Kobayashi, Yasuhiko; Kiguchi, Kenji*; Watanabe, Hiroshi
Nuclear Instruments and Methods in Physics Research B, 206, p.591 - 595, 2003/05
no abstracts in English
Tu, Z.; Kobayashi, Yasuhiko; Kiguchi, Kenji*; Watanabe, Hiroshi
Radiation and Environmental Biophysics, 41(3), p.231 - 234, 2002/08
Times Cited Count：5 Percentile：16.74(Biology)no abstracts in English
Kobayashi, Yasuhiko
Hoshasen Seibutsu Kenkyu, 37(1), p.67 - 84, 2002/03
A single cell irradiation system has been developed for targeting cells individually with a precise number of high-LET heavy ions to elucidate radiobiological effects of exactly one particle and to investigate the interaction of damages produced by separate events. Using the heavy ion microbeam apparatus in TIARA, mammalian cells were irradiated in the atmosphere with a single or precise numbers of heavy ions, 13.0 MeV/u 20Ne or 11.5 MeV/u 40Ar, with a spatial resolution of a few microns.
Kobayashi, Yasuhiko; Taguchi, Mitsumasa; Watanabe, Hiroshi; Yamamoto, Kazuo*; Yamasaki, Shuhei*; Tu, Z. L.*; Kinjo, Y.*; Kiguchi, Kenji*
Proceedings of 11th International Congress of Radiation Research (ICRR-11), 2, p.182 - 186, 2000/00
no abstracts in English
; Morphological changes of the nuclei and cells after spot irradiationKiguchi, Kenji*; Shima, T.*; Kinjo, Y.*; Tu, Z. L.*; Yamasaki, Shuhei*; Kobayashi, Yasuhiko; Taguchi, Mitsumasa; Watanabe, Hiroshi
JAERI-Review 99-025, TIARA Annual Report 1998, p.53 - 55, 1999/10
no abstracts in English
Tu, Z. L.*; Shirai, Koji*; Kanekatsu, Rensuke*; Kiguchi, Kenji*; Kobayashi, Yasuhiko; Taguchi, Mitsumasa; Watanabe, Hiroshi
Nihon Sanshigaku Zasshi, 68(6), p.491 - 500, 1999/00
no abstracts in English
Tu, Z. L.*; Yamasaki, Shuhei*; Shirai, Koji*; Kanekatsu, Rensuke*; Kiguchi, Kenji*; Kobayashi, Yasuhiko; Taguchi, Mitsumasa; Watanabe, Hiroshi
Nihon Sanshigaku Zasshi, 68(6), p.443 - 453, 1999/00
no abstracts in English
Tanaka, Ryuichi; Kamiya, Tomihiro; Kobayashi, Yasuhiko; Watanabe, Hiroshi
Oyo Butsuri, 65(2), p.168 - 172, 1996/00
no abstracts in English
Ueda, Daisuke*; Funayama, Tomoo; Yokota, Yuichiro; Suzuki, Michiyo; Sakashita, Tetsuya; Kobayashi, Yasuhiko; Shirai, Koji*
no journal, ,
The occurrence of DNA damage-induced cell cycle arrest is consider to depend on the amount and/or seriousness of DNA damage. However, the detailed mechanisms have been obscure. When whole egg of the silkworm in early embryogenesis was subjected to carbon ions, the developmental arrest was observed, however, about 2 hours after irradiation, the mitotic cleavage resumed, indicating the eggs at this stage can induce the cell cycle arrest by checkpoints after irradiation. On the other hand, the locally targeted irradiation with carbon-ion microbeam to 10% of the nuclei was not able to induce the developmental arrest. In the egg, several of abnormal cleaved nuclei were observed, which are considered to be the irradiated nuclei that stop their cleavage. Meanwhile, when 30-40% of nuclei were irradiated, the embryonic development stopped. The result indicate the checkpoint-induced arrest of the silkworm egg at intralecithal cleavage stage may depend on number or ratio of the damaged nuclei.
