نتایج جستجو برای: hypoxanthine
تعداد نتایج: 2621 فیلتر نتایج به سال:
In Archaea repair of uracil and hypoxanthine, which arise by deamination of cytosine and adenine, respectively, is initiated by three enzymes: Uracil-DNA-glycosylase (UDG, which recognises uracil); Endonuclease V (EndoV, which recognises hypoxanthine); and Endonuclease Q (EndoQ), (which recognises both uracil and hypoxanthine). Two archaeal DNA polymerases, Pol-B and Pol-D, are inhibited by dea...
The influence of several factors on parasite growth and 50% inhibitory concentration (IC(50)) for chloroquine was assessed. Most isolates stored at 4 degrees C up to 72 hours grew when they were subsequently cultivated. However, parasite viability sharply decreased from 24 hours, and the mean chloroquine IC(50) decreased significantly (P < 0.05). There was no evidence for selection of pre-cultu...
A stripping method for the determination of xanthine in the presence of hypoxanthine at the submicromolar concentration levels is described. The method is based on controlled adsorptive accumulation at the thin-film mercury electrode followed by a fast linear scan voltammetric measurement of the surface species. Optimum experimental conditions were found to be the use of 1.0 × 10(-3) mol L(-1) ...
Levels of hypoxanthine, xanthine, uric acid (UA), homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA) and creatinine were measured in the cerebrospinal fluid (CSF) of 49 patients with schizophrenia and 21 healthy controls. Twenty-six of the patients were first admissions who had never received antipsychotic treatment. We found significantly lower levels of hypoxanthine in the CSF of th...
BACKGROUND In chronic heart failure, oxidative stress is thought to lead to endothelial dysfunction. In this study, we assessed the effect of home-based exercise training on variables of the NO and purine pathways. METHODS AND RESULTS Eighteen patients and nine controls were randomly assigned in cross-over design to 8 weeks of exercise training (5 days/week, submaximal bicycle ergometer train...
1. Mycophenolic acid, an antibiotic of some antiquity that more recently has been found to have marked activity against a range of tumours in mice and rats, strongly inhibits DNA synthesis in the L strain of fibroblasts in vitro. 2. The extent of the inhibition of DNA synthesis is markedly increased by preincubation of the cells with mycophenolic acid before the addition of [(14)C]thymidine. 3....
To determine whether verapamil prevents depletion of adenine nucleotides during and after severe myocardial ischemia, dogs were subjected to 15 min occlusions of the left anterior descending coronary artery followed by 240 min of reperfusion. One hour before occlusion, dogs were randomly assigned to a treatment group (n = 10) to which an infusion of intravenous verapamil was given until the ons...
(6R)-5,10-Dideaza-5,6,7,8-tetrahydrofolic acid [(6R)DDATHF] is a folate antimetabolite with activity specifically directed against de novo purine synthesis, primarily through inhibition of glycinamide ribonucleotide transformylase. This inhibition resulted in major changes in the size of the nucleotide pools in CCRF-CEM cells. After a 4-h incubation with 1 microM (6R)DDATHF, dramatic reductions...
Malarial hemozoin may play an important role as a target for antimalarial drugs and in disease pathogenesis. A new assay for hemozoin was developed in which the hemozoin was separated from cells by filtration. Trophozoites have substantially more hemozoin than rings, but there are relatively small differences between chloroquine-sensitive and chloroquine-resistant strains. The effects of hemozo...
Deamination of DNA bases can occur spontaneously, generating highly mutagenic lesions such as uracil and hypoxanthine. In Escherichia coli two enzymes initiate repair at hypoxanthine residues in DNA. The alkylbase DNA glycosylase, AlkA, initiates repair by removal of the damaged base, whereas endonuclease V, Endo V, hydrolyses the second phosphodiester bond 3' to the lesion. We have identified ...
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