title: Induction and repair of DNA strand breaks in cultured mammalian cells following fast neutron irradiation.
abstract: Induction and repair of DNA breaks following irradiation with NIRS cyclotron neutrons were studied in cultured mammalian cells (L5178Y) in comparison to those following gamma-rays. The yield of the total single-strand breaks, 3'OH terminals and sites susceptible to S1 endonuclease following fast neutrons was found to be approximately 50 per cent of that following gamma-irradiation. On the other hand, the yield of double-strand breaks was slightly higher after fast neutrons than after gamma-rays. The percentage of the total single-strand breaks remaining unrejoined at 3 hours after post-irradiation incubation was found to be distinctly higher after the fast neutrons than after gamma-rays. The neutron-induced damage appears to carry a higher proportion of alkali-labile lesions compared to gamma-rays. It was concluded that the increase in the yield of double-strand breaks and of unrejoinable breaks is responsible for a high r.b.e. of the cyclotron neutrons.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004247:DNA / Q000235:genetics / Q000302:isolation & purification / Q000528:radiation effects*; D004260:DNA Repair; D005214:Fast Neutrons / Q000627:therapeutic use*; D005720:Gamma Rays; D007940:Leukemia L5178 / Q000532:radiotherapy*; D007942:Leukemia, Experimental / Q000532:radiotherapy*; D051379:Mice; D009502:Neutrons / Q000627:therapeutic use*; D011879:Radiotherapy Dosage; D012062:Relative Biological Effectiveness; D013698:Templates, Genetic / Q000528:radiation effects; D013997:Time Factors
chemical_list: D004247:DNA