The yield of fission neutron-induced chromatid aberrations in G2-stage human lymphocytes: effect of caffeine, hydroxyurea and cytosine arabinoside post-irradiation.
To evaluate the influence of inhibitors of DNA synthesis/repair on the yield of chromosomal aberrations in the G2 phase of the cell cycle, whole-blood cultures of human lymphocytes were exposed to various doses of fission neutrons or X-rays and treated post-irradiation during the last 2.45 h before harvesting, with 5 mM caffeine, 5 mM hydroxyurea (HU) and 0.05 mM cytosine arabinoside (ara-C). The presence of caffeine and HU strongly potentiated the yield of chromatid-type aberrations induced by both neutrons and X-rays. No potentiating effect, except at the highest dose of neutrons, was observed when irradiated cells were subsequently treated with ara-C. Since ara-C strongly potentiated the frequency of chromatid aberrations induced in G2 lymphocytes by X-rays, the results presented here indicate that fission neutrons produce a smaller proportion of lesions, the repair of which can be inhibited by ara-C, compared with the number produced by X-rays. In addition, neutron-induced mitotic delay was shortened by treatment with caffeine, mainly within the first 2 h after irradiation.
Dipartimento di Genetica e Biologia Molecolare, Università La Sapienza, Rome, Italy.
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D002110:Caffeine / Q000494:pharmacology*; D002869:Chromosome Aberrations; D003561:Cytarabine / Q000494:pharmacology*; D004249:DNA Damage; D004260:DNA Repair; D016195:G2 Phase / Q000528:radiation effects*; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology*; D008214:Lymphocytes / Q000528:radiation effects; D009502:Neutrons
D003561:Cytarabine; D002110:Caffeine; D006918:Hydroxyurea