[Influence of hydroxyurea on DNA synthesis of human bone marrow in vivo (author's transl)].

Four patients, who suffered from malignant, disseminated tumors but had a morphologically intact bone marrow, where given a peroral Hydroxyurea (HU) infusion in a concentration of about 5 x 10(-4) mol over a period of 10 h. As indicator of the DNA synthesis the 3H-TdR-incorporation of bone marrow, gained by puncture before, during, and/or after HU application, was measured. While using HU, the DNA synthesis was extensively inhibited. Fourteen to 16 h after discontinuing the HU it increased by the factor 1.5 to 2 of the initial value, i.e., before treatment. This is interpreted as a partial synchronization of bone marrow cells where effects of cell depletion and recruitment are not to be entirely excluded, Toxicity, such as the decrease of peripheral blood cells or nausea, did not occur.