Radioprotection of radiation damage fixed by misonidazole in Chinese hamster cells--a rapid-mix study

The indirect effect in the fixation of radiation damage by misonidazole was studied using the rapid-mix apparatus. Under rapid-mix conditions it was shown that the time scale of radiosensitization by misonidazole can be resolved into two components [S. Kandaiya et al., in Proceedings of the Seventh Symposium on Microdosimetry (J. Booz et al., Eds.), pp. 1117-1132, 1980; D. W. Whillans and J. W. Hunt, Radiat. Res. 90, 126-141 (1982)]. Dimethyl sulfoxide (DMSO), a known radioprotector, was used as an OH scavenger. The data obtained indicate that approximately 50% of the lesions fixed by misonidazole in each of the two components can be attributed to OH indirect damage produced by indirect means of radiation deposition in the critical target(s).