1994/04/01 by Edouard I. Azzam, G. P. Raaphorst, R. E. J. Mitchel · 2 citations
Biochemistry, Genetics and Molecular Biology · Medicine · #DNA Repair Mechanisms #Effects of Radiation Exposure #Carcinogens and Genotoxicity Assessment #Ionizing radiation #Micronucleus test #Micronucleus #Neoplastic transformation #Radiobiology #Embryo #Biology #Clonogenic assay #Transformation (genetics) #Cell #Irradiation #Cancer research #Andrology #Cell biology #Genetics #Carcinogenesis #Medicine #Radiation therapy #Toxicity #Internal medicine #Cancer #Gene #Physics
paper · doi:10.2307/3578755
openalex publication_date 1994/04/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/16
We have monitored the end points of cellular survival, micronucleus formation and neoplastic transformation frequency to assess adaptation to ionizing radiation in the C3H 10T1/2 mouse embryo cell system. Plateau-phase cells were pre-exposed to an adapting dose of 0.1 to 1.5 Gy low-dose-rate gamma radiation 3.5 h prior to an acute challenge dose of 4 Gy. No adapting dose improved clonogenic survival detectably, whether the cells were plated immediately after the acute exposure or held in plateau phase for 3.5 h before plating. However, all chronic adapting doses resulted in both a reduction in micronucleus frequency in binucleate cells and about a twofold reduction in neoplastic transformation frequency per viable cell when cells were subsequently exposed to the 4-Gy challenge dose. Our data suggest that a low-dose-rate pre-exposure to ionizing radiation induces an adaptive response in C3H 10T1/2 cells, and that this response enhances DNA double-strand break repair when cells are subsequently exposed to a second radiation dose. This enhanced repair appears to be error-free since these adapted cells are also less susceptible to radiation-induced neoplastic transformation.