Immunocytochemical study of the action of cis-dichlorodiamino platinum on the human metaphase chromosome

The reaction of cis-dichlorodiamino platinum (cis-Pt) with the human metaphase chromosome was studied using both Giemsa staining and the action of anti-cis-Pt antibody. Two kinds of experiment were performed: (1) cis-Pt was placed in contact with cells in culture (in vivo tests), (2) cis-Pt was placed in contact with chromosomes fixed on slides (in vitro tests). In vivo, the presence of cis-Pt during phase G1 of the cell cycle is important for the reaction; in vitro, competition between cis-Pt and Giemsa for fixation on chromosomal DNA was shown to occur.