[Problem of enhancing the biological action of ionizing radiation. 11. Comparative evaluation of the radiosensitizing action of metronidazole on newborn and adult mice].

The radiosensitizing effect of metronidazole is most pronounced in conditions of acute hypoxia (mature mice, 5% O2) or anoxia (neonatels, 100% N2) and decreases with increasing O2 content in a gas mixture. The preparation is less effective in neonatal mice, adapted to oxygen deficiency, than in mature animals. The data obtained are discussed with respect to the problem of overcoming the radioresistance of tumours that is conditioned by hypoxic cells.