The effects of post-treatments with caffeine during S and G 2 on the frequencies of chromosomal aberrations induced by thiotepa in root tips of Vicia faba and in human lymphocytes in vitro

Abstract

The effects of post-treatments with caffeine on the frequencies of chromosomal aberrations induced by the trifunctional alkylating agent thiotepa were studied in human lymphocytes and in root tips of Vicia faba. In lymphocytes the frequency of aberrations induced in G 0 or G 1 was most strongly increased when the caffeine post-treatments were given during G 2. In Vicia faba, on the other hand, the frequency of aberrations induced in early interphase was unaffected by post-treatments with caffeine during G 2, but strongly increased when the root tips were exposed to caffeine during the S phase.