title: Difference in DNA strand break by gamma- and beta-irradiations: an in vitro study.
abstract: Lambda DNA (125 micrograms/ml in Tris buffer, pH 7.4) was irradiated with 60Co gamma-rays and 3H beta-rays, respectively, and the number of strand breaks was determined by electrophoresis. Number of single-strand breaks increased linearly with radiation dose in both gamma- and beta-radiations and the relative effectiveness (beta/gamma) was found to be 1.82 in N2 and 1.16 in O2. Number of double-strand breaks increased with the square of the radiation dose in gamma-irradiation, but it increased linearly with radiation dose in beta-irradiation. Therefore, the relative effectiveness (beta/gamma) is higher at lower doses. O2 effects was observed by gamma-irradiation but was minimal after beta-irradiation.
mesh_terms: D001610:Beta Particles; D004247:DNA / Q000528:radiation effects*; D004277:DNA, Single-Stranded / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D010100:Oxygen; D012062:Relative Biological Effectiveness
chemical_list: D004277:DNA, Single-Stranded; D004247:DNA; D010100:Oxygen