[DNA degradation and repair in human laryngeal carcinoma HEp-2 cells after combined exposure to vitamin B12b and ascorbic acid]. / Degradatsiia i reparatsiia DNK v kletkakh épidermoidnoi kartsinomy gortani cheloveka HEp-2 pri sovmestnom deistvii vitamina B12b i askorbinovoi kisloty.

ABSTRACT

The formation and accumulation of DNA fragments containing no more than 23,000 pairs of bases were observed under exposure of human larynx epidermoid carcinoma cells (Hep-2) to "chemical nuclease", oxycobalamin (vitamin B12b) and ascorbic acid (vitamin C). The obtained DNA damages were repaired more slowly than those induced by gamma-irradiation in the dose adequate to the level of DNA damages. DNA reparation was not revealed after washing the cells from vitamin B12b and ascorbic acid, and in the course of cell incubation with ascorbic acid. Vitamin B12b and ascorbic acid separately did not induce degradation of DNA. DNA damages induced by "chemical nuclease" action precede the cell death observed later.