In patients with malignant tumors, changes in the blood count and morphological changes in the nucleoli in peripheral-blood lymphocytes were studied during treatment with Cytembena, Cyclophosphamide, or combinations of both drugs. After administration of Cyclophosphamide (400 mg i.v. daily for 10 days, then 100 mg orally daily), the counts of leukocytes, especially of neutrophils, sank (by 40%
... [Show full abstract] maximally), and the erythrocyte count and the haemoglobin content in blood sank moderately. In peripheral-blood lymphocytes, the proportion of ring-shaped nucleoli (stimulable to synthesis of RNA) reversibly sank, and the proportion of micronucleoli (nonstimulable) rose. After administration of Cytembena (400 mg i.v. daily for 10 days, then 200 mg i.m. at intervals of 2--4 days), neither the leukocyte counts nor the relative percentages of lymphocytic nucleoli signigicantly changed; the mean corpuscular haemoglobin content (MCH) transitorily increased (by 10 percent max.). In the group receiving combined cytostatics (Cytembena 400 mg i.v. daily for 10 days, then 200 mg i.m. at intervals of 2--4 days plus Cyclophosphamide 50 mg orally daily), the erythrocyte count and the haemoglobin content in blood sank moderately. In the population of peripheral-blood lymphocytes in this group, there sank the absolute counts of lymphocytes with ring-shaped nucleoli (by 44% max.) and those with micronucleoli (by 33% max.).