The radiation response of KHT sarcomas following nicotinamide treatment and carbogen breathing.

摘要: Abstract Preclinical investigations have demonstrated that both diffusion- and perfusion-limited hypoxic cells may exist in tumors. One approach to target such cell subpopulations is through the combined application of nicotinamide (NIC) administration carbogen (5% CO 2 :95% O ) breathing. Because pre-irradiation breathing time (PIBT) can markedly influence radiosensitizing effectiveness this gas mixture, present experiments effect localized radiation on transplantable KHT sarcoma was investigated mice receiving NIC while for various periods time. When were given prior therapy, there a minimum tumor survival PIBTs 2–30 min. Longer led loss effect. NIC, administered as 1000-mg/kg dose, effectively enhanced killing if 45 min h radiotherapy. In which either agent its own under optimum conditions (carbogen, 10 PIBT; or 1000 mg/kg irradiation), with range single doses radiation, results showed an enhancement ratio ∼1.9 determined from slopes curves obtained absence presence sensitizer. This sensitizing could not be increased further when conditions.