These studies explore the effects of an epipodophyllotoxin on the membrane transport and metabolism of thymidine in Ehrlich ascites tumor cells. Uptake of 3H after exposure of cells to [3H]-thymidine is characterized by a rapid initial velocity that approximates membrane transport followed by a slower rate of uptake that parallels the accumulation of phosphorylated derivatives of thymidine, pri...

The biochemical mechanisms by which a genetically determined deficiency of adenosine deaminase leads to immunodeficiency are still poorly understood and prompted this study. We have examined the effects of the adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl) adenine hydrochloride (EHNA) upon the response of human peripheral blood mononuclear cells to the mitogen concanavalin A (Con A...

The uptake of thymidine into an acid-soluble pool in normal hamster embryo cells and hamster tumor cells transformed by polyoma virus was studied. It was found that tumor cells exhibited a 4-fold higher capacity than normal cells to incorporate thymidine as phosphorylated products into this pool. This was correlated with a 5to 10-fold higher activity of thymidine kinase in the tumor cell lines....

Human mononuclear cells were exposed to three antiviral agents, stimulated with phytohemagglutinin, and assayed for DNA synthesis with [3H]thymidine uptake and flow cytometric analysis. Cytosine-arabinoside demonstrated inhibition of blastogenic reactivity by both [3H]thymidine uptake and flow cytometric analysis, whereas acyclovir showed no significant suppression. In contrast, (E)-5-(2-bromov...

The uptake of thymidine into an acid-soluble pool in normal hamster embryo cells and hamster tumor cells transformed by polyoma virus was studied. It was found that tumor cells exhibited a 4-fold higher capacity than normal cells to incorporate thymidine as phosphorylated products into this pool. This was correlated with a 5to 10-fold higher activity of thymidine kinase in the tumor cell lines....

Lymphocytes taken from mice chronically infected with Mycoplasma arthritidis exhibited a significant blastogenic response as measured by (3H)thymidine uptake when exposed in vitro to M. arthritidis antigens. The lymphocytes taken from 9 of 12 control mice of similar age exhibited an inhibition of (3H)thymidine uptake when exposed to M. arthritidis antigens.

Endothelin (ET) peptides are potent growth factors that bind to G protein-coupled receptors. Although short-term signals activated by ET receptors have been extensively characterized, relatively little is known about mitogenic signal transduction. We investigated the ET receptor subtype involved in mitogenic signaling in glomerular mesangial cells and the role of protein kinase C (PKC) and prot...

BACKGROUND To investigate the role of mononuclear cells and their products on rat mesangial cell proliferation, we evaluated the effect of peripheral blood mononuclear cells (PBMC) culture supernatant of patients with IgA nephropathy on rat mesangial cells 3[H]-thymidine uptake, and measured the concentration of cytokines in the supernatant to find out which cytokine in PBMC culture supernatant...

We have previously reported that 5'-aminothymidine (5'-AdThd), an antagonist of the feedback inhibition exerted by dTTP that regulates thymidine kinase, enhances the uptake and cytotoxicity of 5-iododeoxyuridine in various human bladder cancer cell lines but not in normal human urothelial cells (HU) propagated in vitro. In this work we have analyzed the factors that could potentially account fo...

We have developed a rapid sampling technique for animal cells in suspension for the purpose of measuring membrane transport in lymphocytes. The method involves rapid centrifugation of cells through a layer of silicone oil into perchloric acid after incubation periods as short as 4 s. Using this method we have described the uptake of thymidine and the uptake and transport systems of adenosine by...