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Urushibara, Ayumi; Ushigome, Takeshi; Shikazono, Naoya; Fujii, Kentaro; Tauchi, Hiroshi*; Yokoya, Akinari
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no abstracts in English
Fujii, Kentaro; Yokoya, Akinari
no journal, ,
Ionizing radiation produces various molecular damages on DNA through the energy deposition to matter. The activities of the repair enzymes could be modified with the chemical structure of DNA damages. We have investigated the radiation effects to DNA using "in situ" spectroscopic methods; mass analysis of the products induced by photo-desorption, spectroscopic analysis for X-ray absorption near edge structure, and the measurement of electron paramagnetic resonance to detected DNA radicals. These analyses enable us to open discussion the ion or radical reaction during irradiation and the reaction pathway to the final product of the DNA molecule. On the other hand, we used not only synchrotron soft X-rays, but also hard X-rays and heavy ions as radiation sources. Then we try to clarify the molecular changes by measuring X-ray absorption near edge structure (XANES) irradiated DNA molecules. The K-shell electrons of the element of DNA molecules can be ionized or excited by the soft X-rays. Therefore we can analyze functional groups appeared in DNA molecules irradiated. We used DNA or related molecules (deoxyribose, nucleobases and nucleotides), plasmid DNA (pUC18) and calf thymus DNA as irradiated samples. We will discuss the relationship between the DNA damage and radiation quality in respect of repairbility of damages.
-irradiation on chemo-attraction to NaCl and food-NaCl associative learning of 
Sakashita, Tetsuya; Ikeda, Daisuke*; Hamada, Nobuyuki; Suzuki, Michiyo*; Tsuji, Toshio*; Wada, Seiichi; Funayama, Tomoo; Kobayashi, Yasuhiko
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no abstracts in English
Kobayashi, Yasuhiko
no journal, ,
no abstracts in English
Funayama, Tomoo; Kakizaki, Takehiko; Wada, Seiichi; Hamada, Nobuyuki*; Sakashita, Tetsuya; Hodatsu, Tsutomu*; Yamada, Naoaki*; Sano, Tadashi*; Natsuhori, Masahiro*; Kobayashi, Yasuhiko; et al.
no journal, ,
Responses of two lines of feline T lymphocytes, FeT-J and FL-4, to ionizing radiation were examined in the present study. FL-4 cells, but not FeT-J, were persistently infected with feline immunodeficiency virus. Cells were irradiated with 
Co- rays at 2 Gy/min. Surviving fractions were evaluated with clonogenic assay. Apoptosis was detected using TdT-mediated dUTP-biotin nick end labeling (TUNEL) method. Changes in nuclear morphology of viable cells were evaluated by double staining with Hoechst 33342 and ethidium bromide. Mean surviving fractions of FL-4 cells were slightly higher than FeT-J for each radiation dose given. However, dose required to reduce to 63 % of surviving fraction was 1.9 Gy in both cell lines. TUNEL assay, however, revealed the maximum frequency of apoptosis in FL-4 cells (
20 %) was lower than in FeT-J cells (
40 %). The time of frequency peak of TUNEL-positive cells in FL-4 was shorter than that of FeT-J. FL-4 cells reached peak level within 24 hours after irradiation, but FeT-J cells needed later than 48 hours after irradiation. Exposure of FL-4 cells to rays resulted in the giant- and the multi- nucleus formation. Nuclear swelling occurred to less extent in FeT-J than FL-4 cells. In conclusion, we found the difference in cellular responses to radiation in two lines of feline T lymphocytes. Modes of cell death of FL-4 cells were non-apoptotic and more research would discover new mechanism associated with apoptosis.
Wada, Seiichi; Kobayashi, Yasuhiko; Funayama, Tomoo; Sakashita, Tetsuya; Yokota, Yuichiro; Matsumoto, Yoshihisa*; Oto, Takayo*; Hosoi, Yoshio*; Suzuki, Norio*; Hamada, Nobuyuki*; et al.
no journal, ,
Clustered DNA damages induced by high LET heavy ions are thought non-repairable or difficult to repair. However, much less is known about the reparability of clustered DNA damages. The major DNA repair pathway in mammalian cells is non-homologous end joining (NHEJ). In this study we investigated NHEJ pathway by exposure to high LET heavy ions, by analyzing responses of Ku to DNA damage induced by high LET heavy ions. pGFP and pGFP-Ku80 were transfected into xrs-5 cells (mutated in Ku80). Cells were irradiated with rays and ion beams (LET=2.7-1610 keV/
m) at TIARA JAERI-Takasaki. Survival rates were measured by colony formation assay. To examine DNA damage and NHEJ pathway induced by heavy ion beams, H2AX and GFP signal on the nuclei were observed. Xrs5-GFP-Ku80 cells were radioresistant to rays and all ion beams, in comparison with xrs5-GFP cells. When the inactivation cross section was calculated to evaluate lethal effects per one particle, the difference of inactivation cross section between xrs5-GFP cells and xrs5-GFP-Ku80 cells became smaller with increasing LET. GFP and H2AX foci on the nuclei co-localized from 10 to 30 min after C (108 keV/m) and Ne ion (321 keV/m) irradiation. While GFP foci were observed for 10 min after Ar ion (1610 keV/m) irradiation, were not observed for 20 min. The difference of LET of ion beams influenced NHEJ responses.
Funayama, Tomoo; Wada, Seiichi; Hamada, Nobuyuki*; Kakizaki, Takehiko; Yokota, Yuichiro; Sakashita, Tetsuya; Kobayashi, Yasuhiko
no journal, ,
no abstracts in English
Furusawa, Yoshiya*; Wang, X.*; Funayama, Tomoo; Kobayashi, Katsumi*; Imaseki, Hitoshi*; Takagi, Keiichi*; Nakamura, Masanobu*; Kashino, Genro*
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no abstracts in English
Shao, C.*; Prise, K. M.*; Furusawa, Yoshiya*; Kobayashi, Yasuhiko; Matsumoto, Hideki*
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no abstracts in English
Wada, Seiichi; Funayama, Tomoo; Matsumoto, Yoshihisa*; Oto, Takayo*; Sakashita, Tetsuya; Hamada, Nobuyuki*; Yokota, Yuichiro; Kakizaki, Takehiko; Hosono, Yoshio*; Suzuki, Norio*; et al.
no journal, ,
no abstracts in English
Saito, Mikio*; Sugihara, Takashi*; Tanaka, Kimio*; Ogiso, Yoichi*; Funayama, Tomoo; Wada, Seiichi; Sakashita, Tetsuya; Kobayashi, Yasuhiko
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no abstracts in English
Aotani, Hideaki*; Funayama, Tomoo; Wada, Seiichi*; Sakashita, Tetsuya; Kobayashi, Yasuhiko; Hasan, K.*; Kaul, S.*; Takakura, Kaoru*
no journal, ,
no abstracts in English
Kanasugi, Yuichi*; Funayama, Tomoo; Wada, Seiichi*; Sakashita, Tetsuya; Kobayashi, Yasuhiko; Takakura, Kaoru*
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no abstracts in English
Hamada, Nobuyuki*; Wada, Seiichi; Funayama, Tomoo; Sakashita, Tetsuya; Kakizaki, Takehiko; Yokota, Yuichiro; Hase, Yoshihiro; Kobayashi, Yasuhiko
no journal, ,
no abstracts in English