Sensitizing effect of Reverin (pyrrolidinomethyltetracycline) on the radiation damage of rat embryos as compared to its effect on other cell systems

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.

Synergistic interaction between vindesine and X-rays in the prenatal development of mice

The modification of radiation damage by various concentrations of the oncolytic drug vindesine was studied macroscopically, using mouse embryos during the early organogenesis (days eight and nine of gestation) as the test system. The analysis at term showed that the developmental toxicity of vindesine depends on the dosage and the time of administration. In the lower dose-range (0.25 and 0.35 mg/kg), the only reaction was growth retardation, whereas higher concentrations (0.5 and 1.0 mg/kg) led mainly to an early resorption of implants. The more differentiated stage (day nine) exhibited a much higher sensitivity to vindesine than the embryo on day eight. Conversely, the harmful action of 0.9 Gy X-rays was restricted to the earlier period of organogenesis. The incidence of abnormalities after irradiation on day eight was 4.5 times higher than the one following exposure on day nine. The combined exposures showed a radiosensitizing capacity of the drug with respect to the teratogenic response on day eight only. The pretreatment with 0.25 mg/kg vindesine potentiated the radiation-induced malformation rate by a factor of 1.7, and the one with 0.35 mg/kg vindesine by a factor of 2.4.