We previously demonstrated that the existence of two affinity states of the pancreatic cholecystokinin (CCK) receptor depends on the presence of ATP.' Subsequently, we established that the effect of ATP to induce two CCK binding affinity states was biochemically mediated by the enzyme nucleoside diphosphate kinase (NDPK) (manuscript in preparation). Nucleoside diphosphate kinase catalyzes the t...

Gemcitabine is a hydrophilic clinical anticancer drug that requires nucleoside transporters to cross plasma membranes and enter cells. Pancreatic adenocarcinomas with low levels of nucleoside transporters are generally resistant to gemcitabine and are currently a clinical problem. We tested whether transfection of human concentrative nucleoside transporter 3 (hCNT3) using ultrasound and lipid s...

Extensively purified rat liver cytosolic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase kinase was used to examine the role of ADP in inactivation of HMG-CoA reductase (EC 1.1.1.34). Solubilized HMG-CoA reductase was a suitable substrate for HMG-CoA reductase kinase. At sufficiently high concentrations of solubilized HMG-CoA reductase, reductase kinase activity approached that measur...

Bacillus cereus 569 spores germinate either with inosine as a sole germinant or with a combination of nucleosides and L-alanine. Whereas the inosine-only germination pathway requires the presence of two different germination receptors (GerI and GerQ) to be activated, the nucleoside/alanine germination pathway only needs one of the two receptors. To differentiate how nucleoside recognition varie...

The aims of our study were to assess the release of cytotoxic nucleoside analogs 5-fluorouracil and 2-chloro-2'-deoxyadenosine from different lactide-glycolide or lactide-caprolactone biodegradable copolymers and the effects of sterilization on this release. The polymers were sterilized either with ethylene oxide at 37 degrees C, or with gamma radiation (15 kGy, 20 kGy, or 25 kGy). The kinetics...

The pyrhnidine-nucleoside : orthophosphate ribosyltransferase (EC 2.4.2.2)) or pyrimidine nucleoside phosphorylase, from Bacillus sfearofhermophilus has been purified and compared with similar enzymes from Bacillus subfilis and Escherichia coli. The enzyme is stable at 60°, appears to be induced by either uridine or thymidine, and has a molecular weight of approximately 78,000. Unlike nucleosid...

The antiviral activity of nucleoside reverse transcriptase inhibitors is often limited by ineffective phosphorylation. We report on a nucleoside triphosphate (NTP) prodrug approach in which the γ-phosphate of NTPs is bioreversibly modified. A series of TriPPPro-compounds bearing two lipophilic masking units at the γ-phosphate and d4T as a nucleoside analogue are synthesized. Successful delivery...

BACKGROUND The potential prognostic value of human equilibrative nucleoside transporter1 in pancreatic cancer receiving gemcitabine-based chemotherapy is variably reported. OBJECTIVE The objective of this study was to conduct a systematic review of literature evaluating human equilibrative nucleoside transporter1 expression as a prognostic factor in pancreatic cancer receiving gemcitabine-bas...

The thymus is a site of active T-lymphoid cell proliferation and DNA synthesis. In this study, the capacity of human thymocytes for nucleoside transport was assessed both by cytosine arabinoside influx and by equilibrium binding of nitrobenzylmercaptopurine riboside (NBMPR), a specific ligand for the equilibrative nucleoside transporter of leukocytes. The proportion of freshly isolated thymocyt...

Nine fluorescent 5'-6-locked nucleosides were synthesized by condensation of various 1,2-diketones with 5-amino-2'-deoxycytidine. The nucleosides have different substituents on the pyrazine core structure, ranging from two methyl groups to polyaromatic rings. The photophysical properties of each nucleoside were determined, with the nucleosides displaying diverse absorption and emission maxima, ...