RESPONSE OF MURINE SMALL-INTESTINE TO COMBINED TREATMENT WITH FOSTRIECIN AND X-RAYS

This radiobiological investigation was based on the measurements of crypt cell survival in mouse small intestine when the animals were injected with a single dose of fostriecin or streptomycin, and subsequently irradiated to the whole body with graded doses of X rays. The experimental data obtained indicated that fostriecin decreased the isoeffect dose to murine intestine by a factor of 2.3, whereas streptomycin did not influence the radiation response. The biological effects of fostriecin on various tumour cell systems in vitro and in vivo are briefly reviewed. The possible basic mechanisms involved in the radiosensitizing action of fostriecin and the implications of these results in the radiation protection of normal tissues are discussed.