Repair (or recovery) effects in quiescent Chinese hamster cells: an attempt at classification

Increased survival of density-inhibited Chinese hamster cells after a variety of treatments is analyzed in terms of half-time of "repair," magnitude of repair, and dependence upon nutrient medium during the repair interval. At least three different systems are identified: X-ray-like, UV-like, and an entirely different system after heat shock. Repair after methyl methanesulfonate and after visible light (in bromodeoxyuridine-substituted cells) may be interpreted as a superposition of the X-ray and UV-like repair systems.