Radioprotection by thiazolidines at the cellular level.

Radioprotection by a number of thiazolidine derivatives was studied in vitro. Reproductive integrity of single cells was used as a parameter for survival after irradiation. Thiazolidine itself did not protect when dissolved in culture medium, but a good protective activity was found when it was dissolved in rat blood.

In vitro evaluation of some latent radioprotective compounds.

In tissue culture, protection against X-irradiation by a number of cysteamine derivatives was studied and the results were compared with data obtained in mice. Compounds with a covered SH group, like WR 638, cysteamine phosphate, WR 2721, and AE 48527, showed practically no protection when dissolved in tissue-culture medium, but developed a protective activity when dissolved in rat blood. Thiol measurements demonstrated that in rat blood the compounds were partly hydrolysed to thiols.

Radiosensitization of mammalian cells by diamide.

The effect of diamide on the radiosensitivity of T-cells was investigated under oxic and anoxic conditions. The compound was found to sensitize the cells under both conditions. Under oxic conditions, exposure for 10 min before and during irradiation to 0.

Influence of rat blood on radiation protection of mammalian cells by cysteamine and cystamine in vitro.

The protective effect of cystamine and cystamine on T-cells in normal growth-medium was studied in the presence of whole rate blood (WRB). The protective effectiveness of both agents was increased by the addition of WRB, but much less so on the activity of cystamine. In the presence of WRB a dose-reduction factor of 1-5 was obtained at the low concentration of 0-05 mM cysteamine.