Unusual Alkaline Elution Pattern Induced in Mammalian Cell DNA by Fast Neutrons p(34) + Be

Summary

Syrian hamster fibroblasts (cell line BHK 21/13) were exposed to p(34) + Be fast neutron irradiation and their DNA analysed by the alkaline elution technique. The elution profiles showed an unusual tailing off, characteristic of neutron-irradiated samples, suggesting the presence of a modification in DNA induced by the neutrons. This was not seen with ⁶⁰Co gamma-irradiation. In neutron-irradiated samples the alteration of DNA appeared to persist even after 2 h of post-treatment incubation (37°C) indicating the absence of repair. The modification of DNA induced by neutrons provides a possible explanation for the reduction of the shoulders in survival curves obtained with neutrons, and the high RBE of neutrons.