Accumulation of Cells at G_2/M Stage by Low Dose-Rate Irradiation Renders the Cell Population More Susceptible to the Subsequent Induction of 6-Thioguanine-Resistant Mutations by ^<252>Cf Fission Neutrons

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Author(s)

    • TAUCHI Hiroshi
    • Department of Radiation Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University
    • NAKAMURA Nori
    • Department of Genetics, Radiation Effects Research Foundation
    • KOMATSU Kenshi
    • Department of Radiation Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University
    • SAWADA Shozo
    • Department of Radiation Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University

Abstract

A previous study on mutagenesis by <SUP>252</SUP>Cf radiation in mouse L5178Y cells showed that the frequency was higher when the dose was delivered chronically, which was in sharp contrast to the results by gamma-rays (Nakamura and Sawada, 1988). A subsequent study using synchronized cells revealed that the cells at G<SUB>2</SUB>/M stage were uniquely sensitive to mutation induction by <SUP>252</SUP>Cf radiation but not so by gamma-rays (Tauchi et al, 1993). We carried out the present study to test the possibility that radiation-induced G<SUB>2</SUB> block may be a major determinant of the inverse dose-rate effect following chronic <SUP>252</SUP>Cf radiation.<BR> Growing cell population was first subjected to conditioning gamma or <SUP>252</SUP>Cf radiation with different dose-rates, followed by cell cycle distribution analysis and <SUP>252</SUP>Cf mutagenesis. We found that G<SUB>2</SUB>/M fraction increased by 3- to 4-fold when the conditioning doses (2 Gy of gamma or 1 Gy of <SUP>252</SUP>Cf radiation) were delivered chronically over 10 hours but only slightly so when the same doses were delivered for 1 hour or less. Subsequent <SUP>252</SUP>Cf irradiation gave higher mutation frequencies in the cells pre-irradiated with gamma-rays over a protracted period of time than in those with higher dose-rate gamma-rays. These results suggest that radiation-induced G<SUB>2</SUB> block would be at least partly (but can not be totally) responsible for the inverse dose-rate effect.

Journal

  • Journal of Radiation Research

    Journal of Radiation Research 37(1), 49-57, 1996-03

    Journal of Radiation Research Editorial Committee

References:  20

Cited by:  3

Codes

  • NII Article ID (NAID)
    110002338398
  • NII NACSIS-CAT ID (NCID)
    AA00705792
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    04493060
  • Data Source
    CJP  CJPref  NII-ELS  J-STAGE  NDL-Digital 
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