Partenaires

CNRS


Rechercher


Accueil > Publications > Recherche par années > Années 1990 > 1996

Spotheim-Maurizot, M ; Savoye, C ; Sabattier, R ; Charlier, M

Comparative study of DNA radiolysis by fast neutrons and gamma-rays.

Bulletin Du Cancaer-Radiotherapie 83 Suppl 27s-31s

par Administrateur - publié le

Abstract :

The effect of fast neutrons on cells is different from that of gamma-rays : the relative (to gamma) biological effect (RBE) is higher than one and the oxygen enhancement ratio (OER) is lower than that of gamma-rays. We searched for differences between the effects of the two radiations on DNA, the critical target of radiations. Using a model plasmid DNA we observed that for the same absorbed dose, fast neutrons induce twice fewer single strand breaks (SSB) and 1.5 more double strand breaks (DSB) than gamma-rays. A transition metal ion, the Cu++, is a better sensitizer of DNA breakage with fast neutrons than with gamma-rays. In anoxia, cysteamine, a positively charged thiol, is a better radioprotector against neutrons than against gamma-rays. In presence of cysteamine, the OER is lower for neutrons than for gamma-rays. These results are discussed in terms of different physical properties of the two types of radiation.