The Role of Superoxide Radicals in the Oxygen Enhancement of Radiation Damage.
Final rept. 1 Jul 74-29 Jun 77,
DUKE UNIV MEDICAL CENTER DURHAM N C
Pagination or Media Count:
The oxygen enhancement of the lethality of x-ray irradiation of dilute suspensions of Escherichia coli is strikingly diminished by superoxide dismutase or by catalase, added to the suspending medium. This implicates both O2- and H2O2 as agents of the O.E.R. Since O2- and H2O2 have previously been seen to lead to the production of OH in biochemical systems, the effects are tested of scavengers of such radicals. As expected, mannitol or histidine also decreased the O.E.R. Since catalase and superoxide dismutase could be shown not to move from the medium into the cells, the protections caused by these enzymes were due to actions in the suspending medium. Hence O2- and H2O2 generated in the medium are intermediates in the O.E.R.
- Weapons Effects (Biological)