[Weakening of the ultraviolet ray-induced unscheduled DNA synthesis in human lymphocytes in extreme old age].

The intensity of unscheduled DNA synthesis was studied in UV-irradiated (10--15 J/m2) peripheral blood lymphocytes of 80--90 years old persons. In these extreme old age persons, reparative DNA synthesis was found sufficiently reduced in comparison with that in middle aged (20--43 years old) ones. The role of DNA repair processes in ageing is under discussion.