title: Influence of cysteamine on differential staining of BUdR-substituted human chromosomes.
abstract: In 5-bromodeoxyuridine (BUdR)-substituted human chromsomes stained with 4'-6-diamidino-2-phenylindole (DAPI) differential staining is suppressed totally by the H+-donor cysteamine (concentration 0.08 M). We propose that differential staining appears because the double BUdR-substituted chromatid will be disintegrated via a photosensitive dye-visible light system. It is suggested that cysteamine prevents the production of strand breaks in DNA and, consequently, differential staining in BUdR-substituted chromosomes. Furthermore it is shown that differential staining with DAPI causes irreversible changes in the double BUdR-substituted chromatid. This finding can be explained with the above mentioned mechanism.
mesh_terms: D001973:Bromodeoxyuridine; D002877:Chromosomes, Human / Q000187:drug effects / Q000648:ultrastructure*; D003543:Cysteamine / Q000494:pharmacology*; D006801:Humans; D013194:Staining and Labeling
chemical_list: D003543:Cysteamine; D001973:Bromodeoxyuridine