Cellular inactivation and chromosomal aberrations: initial damage.
It has been proposed that unrepaired or misrepaired complex lesions of DNA are responsible for cell inactivation and chromosomal aberrations. The detailed features of the critical damage and the nature of initiating physical events are actively investigated. We studied the role of inner-shell (core) ionizations in DNA atoms is studied. Ultrasoft X-rays from LURE synchrotron radiation have been used to mimic core events induced by ionizing radiations. For biological matter, inner-shell photoionization is indeed the main interaction channel of these radiations. Moreover, by tuning the X-ray energy below and above the carbon K-threshold, it is possible to achieve a two-fold increase in the number of core-ionizations in DNA for a same dose. Cell survival and chromosome aberrations have thus been studied at three iso-attenuated energies: 250, 350, and 810 eV. Relative biological efficiencies (RBEs) for cell inactivation and chromosome aberrations were found to be strongly correlated with the yields of core events in DNA.
Boissiére
Arnaud
A
Groupe de Physique des Solides, Universités Paris 6 et Paris 7, Paris, France.
Eschenbrenner
Anne
A
Gobert
François
F
Hervé du Penhoat
Marie-Anne
MA
Abel
François
F
Lamoureux
Michele
M
Martins
Luis
L
Politis
Marie-Françoise
MF
Ricoul
Michéle
M
Touati
Alain
A
Sage
Evelyn
E
Sabatier
Laure
L
Chetioui
Annie
A
D000818:Animals; D002460:Cell Line / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects*; D006224:Cricetinae; D004247:DNA / Q000528:radiation effects*; D004249:DNA Damage / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D011839:Radiation, Ionizing
D004247:DNA