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Kobayashi, Yasuhiko; Funayama, Tomoo; Wada, Seiichi; Sakashita, Tetsuya; Kakizaki, Takehiko; Hamada, Nobuyuki*; Yokota, Yuichiro; Furusawa, Yoshiya*
KEK Proceedings 2005-5, p.6 - 8, 2005/10
no abstracts in English
Kobayashi, Yasuhiko; Funayama, Tomoo; Wada, Seiichi; Furusawa, Yoshiya*; Aoki, Mizuho*; Shao, C.*; Yokota, Yuichiro; Sakashita, Tetsuya; Matsumoto, Yoshitaka*; Kakizaki, Takehiko; et al.
Uchu Seibutsu Kagaku, 18(4), p.235 - 240, 2004/12
no abstracts in English
Kobayashi, Yasuhiko; Funayama, Tomoo; Wada, Seiichi; Sakashita, Tetsuya
Uchu Seibutsu Kagaku, 18(3), p.186 - 187, 2004/11
no abstracts in English
Kobayashi, Yasuhiko; Funayama, Tomoo; Wada, Seiichi*; Taguchi, Mitsumasa; Watanabe, Hiroshi
Radiation Research, 161(1), p.90 - 91, 2004/01
A single cell irradiation system has been developed for targeting cells individually with a precise number of heavy ions to elucidate radiobiological effects of exactly one particle and to investigate the biological effects of low fluence irradiation with HZE particles. Using the heavy ion microbeam apparatus installed at JAERI-Takasaki, mammalian cells were irradiated in the atmosphere with a single or precise numbers of ions, 13.0 MeV/u 20Ne or 11.5 MeV/u 40Ar. The number of ions traversed the cells attached on the ion track detector CR-39 were counted with a plastic scintillator. Immediately after the irradiation, the position and the number of ion tracks traversed the cell was detected with etching of CR-39 from the opposite side of the cell with alkaline-ethanol solution at 37
C. The growths of the cells were observed individually up to 60 hours after irradiation.
Funayama, Tomoo; Wada, Seiichi; Kobayashi, Yasuhiko
Radiation Research, 161(1), p.111 - 112, 2004/01
Using the heavy ion microbeam apparatus, mammalian cells were irradiated in the atmosphere with a single or precise numbers of 
Ar heavy ions (11.5 MeV/u) with a spatial resolution of a few microns. Positional data of the individual cells attached on the ion track detector CR-39 were obtained at the off-line microscope before irradiation, then the targeting and irradiation of the cells were performed semi-automatically at the on-line microscope of the microbeam apparatus according to the obtained data. Immediately after irradiation, the position and the number of ion tracks traversed the cell was detected with etching of CR-39 at 37 C. The growths of the cells were observed individually up to 60 hours after irradiation. The continuous observation of the individual cell growth indicated that single Ar ion traversal of cell nucleolus resulted to complete growth inhibition of the irradiated cells.
Kobayashi, Yasuhiko; Funayama, Tomoo; Wada, Seiichi; Taguchi, Mitsumasa; Watanabe, Hiroshi
Nuclear Instruments and Methods in Physics Research B, 210(1-4), p.308 - 311, 2003/09
A method for detecting the ion hit tracks on the mammalian cultured cells at the irradiation time was established. The cells were attached to the ion track detector CR-39 (100 
m thick), then irradiated with 13.0 MeV/u 20Ne or 11.5 MeV/u 40Ar ion beams. Immediately after the irradiation, the cells were refilled with medium, then the CR-39 was etched from the opposite side of the cell with alkaline-ethanol solution at 37C. With the 15 min etching treatment, we obtained the accurate information about the spatial distribution of irradiated ions without significant effect on the cell growth. The continuous observation of the individual cell growth indicated that the growth of ion hit cell was reduced compared with that of non-irradiated one.
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.
Kamiya, Tomihiro; Sakai, Takuro; *; *; Hirao, Toshio
F-113-'98/NIES, p.60 - 63, 1998/00
no abstracts in English
