No abstract

No abstract

Phenothiazine tranquilizers are widely used pharmaceuticals that have been associated with side effects, such as formation of cataracts, that seem related to light exposure. Because patients may use them over extensive time periods, it is important to determine what deleterious cellular effects these drugs may cause and, if possible, to select or design drugs that do not cause such effects. The results reported here demonstrate that chlorinated phenothiazine drugs can be photoactivated to mutagenic species, whereas the nonchlorinated analogues do not possess this characteristic. None of the phenothiazines tested is mutagenic in the dark. Mutagenicity was observed only in strains of Salmonella typhimurium that lacked excision repair of DNA, and the mutagenicity was elevated in strains that contained the plasmid pKM101, which may enhance error-prone repair.

No abstract

A hypothesis is presented regarding the importance of desoxyribonuclei acid (DNA) repair for maintenance of lens clarity. It is proposed that unrepaired or incorrectly repaired damage to lens epithelial cell DNA may result in decreased lens transparency either by altering normal metabolism in the epithelium or subsequently by affecting lens cell differentiation and protein synthesis in the lens cortex.