Induction and rejoining of DNA double-strand breaks in V79-4 mammalian cells following gamma- and alpha-irradiation.

摘要: The induction and rejoining of DNA double-strand breaks (dsbs) in V79-4 mammalian cells following irradiation by 60Co gamma-rays 238Pu alpha-particles (average LET 120 keV microns-1) under aerobic conditions have been determined using both the sucrose sedimentation filter elution techniques non-denaturing conditions. Cellular inactivation was also determined. dependence initial yield dsbs at 277 K on dose is linear with a relative biological effectiveness (RBE) for 0.85 +/- 0.14 (sedimentation) 0.68 0.12 (elution) compared gamma-rays. ability to rejoin 310K significantly reduced alpha-irradiations only 30-50% rejoined 3-h incubation period. With low radiation, > 90% are within 3 h 20 Gy. RBE cellular be 4.0 1% survival level. From dimensions D0-value alpha-particles, it that, average, 4.7 tracks traverse cell nucleus per lethal lesion. Under hypoxic conditions, values (10% level) approximately 3.0 11.8 respectively. these findings, suggested that residual damage not reflected inactivation. It inferred difference repair various lesions reflection differences complexity clustered produced radiations.