Additive effects shown by combinations of nitroxyl and electron-affinic hypoxic cell sensitizers

Nitroxyl free radical sensitizers enhance the radiation killing of K12 RecA- bacteria to a greater extent than does oxygen. Unlike oxygen, electron-affinic sensitizers of the nitro-aromatic type cannot compete to reduce this ''superoxic'' level of sensitization. Instead, the two types of sensitizer, when used in combination, are additive in their effect on reducing the survival of K12 RecA-, suggesting that they operate on different types of radiation-induced lesion. Experiments with other Escherichia coli strains show similar effects