Increased salt intake attenuates the endothelium-dependent dilation of skeletal muscle arterioles by abolishing local nitric oxide (NO) activity. There is evidence of oxidative stress in arteriolar and venular walls of rats fed a high-salt diet, and depressed arteriolar responses to acetylcholine (ACh) in these rats are reversed by scavengers of reactive oxygen species (ROS). In this study, we ...

S-Nitrosothiols (RSNO) occur in vivo and have been proposed as nitric oxide (.NO) storage and transport biomolecules. Still, the biochemical mechanisms by which RSNO release .NO in biological systems are not well defined, and in particular, the interactions between reactive oxygen species and RSNO have not been studied. In this work, we show that xanthine oxidase (XO), in the presence of purine...

AIMS To evaluate the effects of allopurinol in lens induced uveitis (LIU) by morphological methods and to compare these effects with those of steroids and a combination of both drugs biochemically and morphologically. METHODS Lipid peroxides (LPO) of the retinal tissue were determined by two different methods (thiobarbituric acid assay (TBA) and high performance liquid chromatography expresse...

We have previously demonstrated that hydrogen peroxide (H2O2) mediates flow-induced vascular dilation in rat small mesenteric arteries. In the present study, the source of this flow-induced H2O2 was explored. The arteries were pressurized to 50 mm Hg and preconstricted with phenylephrine. Intraluminal flow reversed the effect of phenylephrine, resulting in vascular dilation. Cytochrome P450 (CY...

We have identified, cloned, and sequenced the hca cluster encoding the dioxygenolytic pathway for initial catabolism of 3-phenylpropionic acid (PP) in Escherichia coli K-12. This cluster maps at min 57.5 of the chromosome and is composed of five catabolic genes arranged as a putative operon (hcaA1A2CBD) and two additional genes transcribed in the opposite direction that encode a potential perme...

We sincerely appreciate the interest shown by Dr T Neogi and colleagues concerning our 2016 revised European League Against Rheumatism (EULAR) recommendations for the management of gout. Dr T Neogi and colleagues raised concern with the ninth item, in which we recommend to adjust the maximum dosage of allopurinol according to the creatinine clearance (CrCl) in order to decrease the risk of seve...

Hypoxanthine phosphoribosyltransferase (inosine monophosphate: pyrophosphate phosphoribosyltransferase EC 2.4.2.8) has been purified SO-fold from an acid-treated lysate of human erythrocytes. The average particle weight of the enzyme was estimated by gel filtration at 60,000. Between the pH values of 7.1 and 9.1 no marked difference in the initial velocity of IMP synthesis was observed. Kinetic...

Leishmania donovani and Leishmania braziliensis grown in culture formed millimolar concentrations of allopurinol ribonucleoside 5’-monophosphate from [6“C]allopurinol. In addition, allopurinol l-ribonucleoside, oxipurinol riboside 5’-monophosphate, and three new metabolites of allopurinol, namely, 4-aminopyrazolo(3,4-d)pyrimidine ribonucleoside V-monophosphate and the corresponding diand tripho...

DHPS (dihydropteroate synthase) catalyses an essential step in the biosynthesis of folic acid and is the target for the sulfonamide group of antimicrobial drugs. In the present paper we report two crystal structures of DHPS from the respiratory pathogen Streptococcus pneumoniae: the apoenzyme at 1.8 A (1 A=0.1 nm) resolution and a complex with DHPP (6-hydroxymethyl-7,8-dihydropterin monophospha...

OBJECTIVES Allopurinol is a uric acid lowering drug used in the treatment of gout and the prevention of tumor lysis syndrome. Allopurinol and its active metabolite oxipurinol inhibit xanthine oxidase, which forms uric acid from xanthine and hypoxanthine. Therapeutic drug monitoring is an important option for evaluation and optimization of allopurinol treatment in case of renal impairment, inter...