Mutation induction by different dose rates of gamma rays in near-diploid mouse cells in plateau- and log-phase culture.
Induction of mutation to 6-thioguanine resistance was studied in cultured near-diploid mouse cells (m5S) in plateau and log phase after exposure to gamma rays at dose rates of 30 Gy/h, 180 mGy/h, or 13 mGy/h. In plateau-phase culture, lowering the dose rate from 30 Gy/h to 13 mGy/h resulted in an increase in cell survival and a marked decrease in induced mutation frequency. On the other hand, in the log-phase culture, the magnitude of the dose-rate effects was not as marked as in the plateau-phase culture, particularly within a dose range below 5 Gy. These results, together with those indicating the inverse dose-rate effects in growing mouse leukemia cells (Radiat Res. 115, 273-280, 1988), demonstrate the significant influence of cell growth that takes place during protracted irradiation, particularly for the induction of mutation.
Furuno-Fukushi
I
I
Division of Biology, National Institute of Radiological Sciences, Chiba-shi, Japan.
Aoki
K
K
Matsudaira
H
H
D000818:Animals; D002455:Cell Division; D002470:Cell Survival / Q000528:radiation effects; D002478:Cells, Cultured; D005720:Gamma Rays; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D007399:Interphase; D051379:Mice; D009154:Mutation; D011829:Radiation Dosage
D007041:Hypoxanthine Phosphoribosyltransferase