The deoxyuridine (dU) suppression test assesses the capacity of marrow cells or activated lymphocytes to convert exogenous dU into thymidine. In addition, the effect of the added cobalamin or folate on the result is used to determine the nature of the deficiency in megaloblastic marrows. This study shows that folates have a considerable effect on the uptake of labelled thymidine by marrows from...

The effects of benzaldehyde, which has been found in figs as a carcinostatic element, were studied on the uptake of nucleosides, 2-deoxy-D-glucose, and amino acids into simian virus 40-transformed rat fibroblast cells (SV40-transformed cells) and into the parent normal cells (normal cells). Benzaldehyde, at the concentrations of 25 to 100 microgram/ml at which the selective growth inhibition ag...

Malignant cells have enhanced sensitivity to inhibition of growth by thymidine. Cell growth of the permanent lymphoid cell line CCRF-CEM, originating from a patient with acute lymphoblastic leukemia, is inhibited by 3 x 10(-5) M thymidine, compared to 1 to 5 x 10(-3) M thymidine required to inhibit growth of normal lymphoid lines. Thymidine-resistant cells were isolated at a frequency of approx...

Uptake of (3)H-thymidine by resting cells of Pediococcus cerevisiae was found to be energy- and temperature-dependent. The pH optimum was between 6.5 and 8.0, and after 2 min of incubation most of the radioactivity was found in the deoxyribonucleic acid (DNA) fraction. Iodoacetate at a concentration of 10(-2)m caused a 50% inhibition of uptake. Preincubation of resting cells for 10 min with fol...

Isolated rat liver cells have been used to measure DNA repair synthesis induced by ultraviolet light and aflatoxin. Age, sex, and diet of the rats were found to influence DNA repair in rat liver cells, as measured by [3H]thymidine uptake by the cells. These effects were found to be due to variations in the thymidine pool size and should serve to indicate that high-specific-activity thymidine (i...

Insulin has been shown to directly affect blood vessel tone and to promote vascular hypertrophy, but the mechanism of these actions remains uncertain. Because angiotensin I (Ang I)-converting enzyme inhibitors have been shown to improve insulin action and to impede the progression of vascular hypertrophy in hypertensive animal models, it is possible that the vascular properties of insulin may b...

We have studied the effect of pH on the interactions between thymidine kinase, thymidine triphosphate, and 5'-amino-2',5'-dideoxythymidine (S'-Ad'l'hd) in purified preparations of the enzyme and in intact 647V cells, a human bladder cancer cell line. Thymidine kinase is competitively inhibited by S'-AdThd. dI'll' feedback inhibits in a noncompetitive fashion. However, S'-AdThd partially reverse...

We have studied the effect of pH on the interactions between thymidine kinase, thymidine triphosphate, and 5'-amino-2',5'-dideoxythymidine (S'-Ad'l'hd) in purified preparations of the enzyme and in intact 647V cells, a human bladder cancer cell line. Thymidine kinase is competitively inhibited by S'-AdThd. dI'll' feedback inhibits in a noncompetitive fashion. However, S'-AdThd partially reverse...