[Partial synchronization of tumor cells in vivo with hydroxyurea (author's transl)].

For the partial synchronization of tumor cells, Yoshida ascitic sarcoma bearing rats were treated with Hydroxyurea using two methods, one in the form of a single intraperitoneal injection (0.5 mg/g body weight) and the other by continuous intraascitic infusion over a period of 12h (1.428 mg/g body weight total dose). The synchronization obtained by continuous infusion of Hydroxyurea is superior to that by a one time injection with respect to cell accumulation in one phase of the cell cycle and in the duration of synchronous proliferation. The degree of cell loss caused by infusion depends on the concentration of Hydroxyurea. Concentrations of slightly more than the minimal inhibitory concentration of DNA synthesis cause the least damage to the tumor cells.