INCREASED HYPOTHERMIA SURVIVAL IN MAMMALIAN-CELLS BY REPEATED 37-DEGREES-C SPLIT-DOSE REPAIR

V-79 Chinese hamster cells exposed to hypothermia with repeated higher temperature interruptions (split-doses) significantly improve long-te rm survival of cells stored at 5 or 10-degrees-C. Repair of 10-degrees -C (Range I = 8 to +25-degrees-C) sublethal hypothermic damage is more efficient at 37-degrees-C than repair of 5-degrees-C (Range II = 0 to +8-degrees-C) sublethal damage. In Range I, citiolone (N-acetyl-homoc ysteine-thiolactone) protects, but may slightly inhibit repair. DMTU ( dimethylthiourea) does not protect, but may enhance repair. In Range I I, glycine protects but may inhibit repair, while citiolone does not p rotect but may enhance repair. Repair of 5-degrees-C hypothermia damag e is not very temperature dependent, while repair of 10-degrees-C hypo thermia damage shows some temperature dependence.