Hypoxic cell radiosensitization by 8-methoxypsoralen.

8-Methoxypsoralen has been shown to act as a radiosensitizer of hypoxic bacteriophage and bacteria. Radiosensitization of bacteriophage requires irradiation in the presence of excess scavenger. Bacterial radiosensitization requires deficiencies in uvr and rec genes. For the drug to be effective it must be present during irradiation. Pulse radiolysis studies have shown that, like electron-affinic radiosensitizers, 8MOP can efficiently oxidize free radicals. Unlike oxygen and most electron-affinic radiosensitizers 8MOP does not act in a purely dose-modifying fashion, and can radiosensitize beyond the oxygen effect.