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Yokoyama, Sumi*; Tsujimura, Norio; Hashimoto, Makoto; Yoshitomi, Hiroshi; Kato, Masahiro*; Kurosawa, Tadahiro*; Tatsuzaki, Hideo*; Sekiguchi, Hiroshi*; Koguchi, Yasuhiro*; Ono, Koji*; et al.
Journal of Radiation Protection and Research, 47(1), p.1 - 7, 2022/03
Background: In Japan, new regulations that revise the dose limit for the lens of the eye (the lens), operational quantities, and measurement positions for the lens dose were enforced in April 2021. Based on the international safety standards, national guidelines, the results of the Radiation Safety Research Promotion Fund of the Nuclear Regulatory Authority, and other studies, the Working Group of Radiation Protection Standardization Committee, the Japan Health Physics Society (JHPS) developed a guideline for radiation dose monitoring for the lens. Materials and Methods: The Working Group of the JHPS discussed the criteria of non-uniform exposure and the management criteria set to not exceed the dose limit for the lens. Results and Discussion: In July 2020, the JHPS guideline was published. The guideline consists of three parts: main text, explanations, and 26 questions. In the questions, the corresponding answers were prepared, and specific examples were provided to enable similar cases to be addressed. Conclusion: With the development of guideline on radiation dose monitoring of the lens, radiation managers and workers will be able to smoothly comply with revised regulations and optimise radiation protection.
Yokoyama, Sumi*; Iwai, Satoshi*; Tsujimura, Norio; Hashimoto, Makoto; Yoshitomi, Hiroshi; Kato, Masahiro*; Kurosawa, Tadahiro*; Tatsuzaki, Hideo*; Sekiguchi, Hiroshi*; Koguchi, Yasuhiro*; et al.
Proceedings of 15th International Congress of the International Radiation Protection Association (IRPA-15) (Internet), 8 Pages, 2022/00
Wada, Seiichi*; Ando, Tatsuhiko*; Watanabe, Aya*; Kakizaki, Takehiko*; Natsuhori, Masahiro*; Funayama, Tomoo; Sakashita, Tetsuya; Yokota, Yuichiro; Kobayashi, Yasuhiko
JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 79, 2015/03
So far, we clarified that X-ray irradiation induced cell killing by bystander effect mediated-secreted factor. This phenomenon was related with sphingomyelinase (SMase). In this study we analyzed mechanism of secreted SMase from irradiated cells after irradiation. SMase was detected in the culture medium after irradiation by SDS-PAGE. Then, SMase was detected in the exosome of culture medium, but not out of exosome after irradiation. This result indicates that SMase was secreted as exosome from the irradiated cells.
Kakizaki, Takehiko; Hamada, Nobuyuki*; Sakashita, Tetsuya; Wada, Seiichi*; Hara, Takamitsu*; Funayama, Tomoo; Hodatsu, Tsutomu*; Natsuhori, Masahiro*; Sano, Tadashi*; Kobayashi, Yasuhiko; et al.
Journal of Veterinary Medical Science, 69(6), p.605 - 609, 2007/06
Times Cited Count：1 Percentile：13.67(Veterinary Sciences)no abstracts in English
Sano, Tadashi*; Wada, Seiichi*; Suzuki, Keiko*; Natsuhori, Masahiro*; Kakizaki, Takehiko; Ito, Takashi*; Nakazawa, Konomi*; Kobayashi, Yasuhiko; Ito, Nobuhiko*
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 115, 2007/02
-rays and energetic carbon ionsKakizaki, Takehiko; Hamada, Nobuyuki*; Funayama, Tomoo; Sakashita, Tetsuya; Wada, Seiichi*; Hodatsu, Tsutomu*; Natsuhori, Masahiro*; Sano, Tadashi*; Kobayashi, Yasuhiko; Ito, Nobuhiko*
Journal of Veterinary Medical Science, 68(12), p.1269 - 1273, 2006/12
Times Cited Count：3 Percentile：23.41(Veterinary Sciences)no abstracts in English
Kakizaki, Takehiko; Hamada, Nobuyuki*; Wada, Seiichi*; Funayama, Tomoo; Sakashita, Tetsuya; Hodatsu, Tsutomu*; Sano, Tadashi*; Natsuhori, Masahiro*; Kobayashi, Yasuhiko; Ito, Nobuhiko*
Journal of Radiation Research, 47(3-4), p.237 - 243, 2006/11
no abstracts in English
Wada, Seiichi; Natsuhori, Masahiro*; Ito, Nobuhiko*; Funayama, Tomoo; Kobayashi, Yasuhiko
Nuclear Instruments and Methods in Physics Research B, 206, p.553 - 556, 2003/05
Times Cited Count：3 Percentile：27.69(Instruments & Instrumentation)Determining the biological effects of a very low number of charged particles crossing the cell nucleus is interest for estimating the risk due to environmental exposure to charged particles. Especially it is necessary to detect the radiation damage induced by a precise number of charged particles in the individual cells. To compare the number of ions traversing the cell and the DNA damage produced by the hit ions, we applied comet assay. Cells attached on the ion track detector CR-39 were irradiated with 17.3 MeV/u 12C, 15.7 MeV/u, 10.4 MeV/u 20Ne and 6.9 MeV/u 40Ar ion beams at TIARA, JAERI-Takasaki. After irradiation, CR-39 was covered with 1 % agarose. After electrophoresis the CR-39 was taken off from the slide glass. The agarose gel on the CR-39 was stained with ethidium bromide and the opposite side of the CR-39 was etched with KOH-ethanol solution at 37 
. We observed that the ion particles with higher LET value induced the heavier DNA damage, even by the same number of ion-hits within the irradiated cells.
Wada, Seiichi*; Natsuhori, Masahiro*; Kobayashi, Yasuhiko; Yamamoto, Kazuo; Ito, Nobuhiko*
JAERI-Review 2000-024, TIARA Annual Report 1999, p.80 - 82, 2000/10
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.
Sano, Tadashi*; Suzuki, Keiko*; Natsuhori, Masahiro*; Kakizaki, Takehiko; Ito, Nao*; Nakazawa, Konomi*; Ito, Nobuhiko*; Wada, Seiichi*; Kobayashi, Yasuhiko
no journal, ,
no abstracts in English
Kakizaki, Takehiko; Hamada, Nobuyuki*; Wada, Seiichi*; Sakashita, Tetsuya; Hara, Takamitsu*; Hodatsu, Tsutomu*; Natsuhori, Masahiro*; Sano, Tadashi*; Funayama, Tomoo; Fukamoto, Kana; et al.
no journal, ,
no abstracts in English
Ito, Takashi*; Wada, Seiichi*; Kakizaki, Takehiko; Kobayashi, Yasuhiko; Natsuhori, Masahiro*; Sano, Tadashi*; Sasaki, Nobuo*; Ito, Nobuhiko*
no journal, ,
no abstracts in English
Kakizaki, Takehiko; Hamada, Nobuyuki*; Wada, Seiichi*; Sakashita, Tetsuya; Funayama, Tomoo; Hodatsu, Tsutomu*; Natsuhori, Masahiro*; Sano, Tadashi*; Kobayashi, Yasuhiko; Ito, Nobuhiko*
no journal, ,
no abstracts in English
Ito, Takashi*; Wada, Seiichi*; Kakizaki, Takehiko; Kobayashi, Yasuhiko; Natsuhori, Masahiro*; Sano, Tadashi*; Sasaki, Nobuo*; Ito, Nobuhiko*
no journal, ,
no abstracts in English
