Search results for "xanthine"
showing 10 items of 139 documents
Detection of Hypoxanthine from Inosine and Unusual Hydrolysis of Immunosuppressive Drug Azathioprine through the Formation of a Diruthenium(III) Syst…
2021
Hypoxanthine (hpx) is an important molecule for both biochemistry research and biomedical applications. It is involved in several biological processes associated to energy and purine metabolism and has been proposed as a biomarker for a variety of disease states. Consequently, the discovery and development of systems suitable for the detection of hypoxanthine is pretty appealing in this research field. Thus, we have obtained a stable diruthenium (III) compound in its dehydrated and hydrated forms with formula [{Ru(µ
Preparation of two sets of 5,6,7-trioxygenated dihydroflavonol derivatives as free radical scavengers and neuronal cell protectors to oxidative damag…
2009
An unusual class of 5,6,7-trioxygenated dihydroflavonols (3a-e and 4a-j) were designed and prepared. Their antioxidative properties were assessed by examining their capacities in several in vitro models, including superoxide anion and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, rat liver homogenate lipid peroxidation inhibition, PC12 cells protection from oxidative damage, and xanthine oxidase inhibition. These dihydroflavonols displayed positive quenching abilities towards O(2)(-) and DPPH free radicals, in which the majority exhibited superior antioxidant properties to Vitamin C. cis-Configurated compound (+/-)-3e demonstrated remarkable inhibition to LPO with an IC(50) value…
l-Carnitine l-tartrate supplementation favorably affects biochemical markers of recovery from physical exertion in middle-aged men and women.
2009
The purpose of this study was to examine the effects of Carnipure tartrate (Lonza, Allendale, NJ) supplementation (total dose of 2 g/d of l-carnitine) on markers of performance and recovery from physical exertion in middle-aged men and women. Normally active and healthy men (n = 9, 45.4 +/- 5.3 years old) and women (n = 9, 51.9 +/- 5.0 years old) volunteered to participate in the investigation. Double-blind, placebo, balanced treatment presentation and crossover design were used with 3 weeks and 3 days of supplementation followed by a 1-week washout period before the other counterbalanced treatment was initiated. After 3 weeks of each supplementation protocol, each participant then performe…
Redox signaling in acute pancreatitis
2015
Acute pancreatitis is an inflammatory process of the pancreatic gland that eventually may lead to a severe systemic inflammatory response. A key event in pancreatic damage is the intracellular activation of NF-κB and zymogens, involving also calcium, cathepsins, pH disorders, autophagy, and cell death, particularly necrosis. This review focuses on the new role of redox signaling in acute pancreatitis. Oxidative stress and redox status are involved in the onset of acute pancreatitis and also in the development of the systemic inflammatory response, being glutathione depletion, xanthine oxidase activation, and thiol oxidation in proteins critical features of the disease in the pancreas. On th…
Protective Effect of Sildenafil against Estradiol-induced ROS production
2010
Several reports suggest that xanthine dehydrogenase (XDH) and its oxidase form (XO) play an important role in various forms of ischemic and vascular injuries. Recently we have demonstrated that 17β-estradiol (E2) induces a significant decrease of the expression and activity of XDH and its conversion to XO in human mammary epithelial cells. E2 is known to induce upregulation of eNOS gene expression in aortic endothelial cells. In light of the ability of XO-derived O2•¯ to combine with •NO to yield ONOO¯, and considering that ONOO¯ converts XDH to XO, it is important to protect tissues against the XO increased activity and ROS increased production, that would in turn react with •NO to augment…
Nitric oxide and excitatory postsynaptic currents in immature rat sympathetic preganglionic neurons in vitro.
1997
Neuronal nitric oxide synthase immunoreactivity was localized to sympathetic preganglionic neurons of the intermediolateral cell column and cyclic GMP immunoreactivity to nerve fibers projecting into the intermediolateral cell column of 20-25-day-old rats. Whole-cell patch-clamp recordings were made from sympathetic preganglionic neurons in spinal cord slices of immature rats and the role of nitric oxide and cyclic GMP on excitatory postsynaptic currents was studied. Superfusing the slices with the nitric oxide precursor L-arginine (300 microM) increased the amplitude of evoked excitatory postsynaptic currents as well as the frequency of spontaneous miniature excitatory postsynaptic current…
Pentoxifylline and Oxypurinol: Potential Drugs to Prevent the “Cytokine Release (Storm) Syndrome” Caused by SARS-CoV-2?
2020
Background: COVID-19, caused by SARS-CoV-2, is a potentially lethal, rapidly-expanding pandemic and many efforts are being carried out worldwide to understand and control the disease. COVID-19 patients may display a cytokine release syndrome, which causes severe lung inflammation, leading, in many instances, to death. Objective: This paper is intended to explore the possibilities of controlling the COVID-19-associated hyperinflammation by using licensed drugs with anti-inflammatory effects. Hypothesis: We have previously described that pentoxifylline alone, or in combination with oxypurinol, reduces the systemic inflammation caused by experimentally-induced pancreatitis in rats. Pentoxifyl…
Effects of caffeine intake on the pharmacokinetics of melatonin, a probe drug for CYP1A2 activity
2003
Aims The aim of this study was to assess the influence of concomitant caffeine intake on the pharmacokinetics of oral melatonin, a probe drug for CYP1A2 activity. Methods Twelve healthy subjects, six smokers and six nonsmokers, were given melatonin (6 mg) either alone or in combination with caffeine (3 × 200 mg). Blood samples for the analysis of melatonin or caffeine and paraxanthine were taken from 1 h before until 6 h after intake of melatonin. Subjects were genotyped with respect to the CYP1A2*1F (C734A) polymorphism. Results When caffeine was coadministered the Cmax and AUC of melatonin were increased on average by 142% (P = 0.001, confidence interval on the difference 44, 80%) and …
Discovery of new antimalarial compounds by use of molecular connectivity techniques.
1999
Abstract Molecular connectivity has been applied to the search for new compounds with antimalarial activity. Linear discriminant analysis and connectivity functions were used to select several potentially suitable drugs which were tested for antimalarial properties by use of an in-vitro micro test which estimates parasite growth by measurement of incorporation of [3H]hypoxanthine. Hexetidine stands out among the compounds selected. Activity assays were performed with Plasmodium falciparum passou and 3CD7 strains, for which the IC50 values (doses resulting in 50% inhibition) were 320 and 400 ng mL−1 respectively. These results are comparable with those obtained for quinine chlorhydrate (IC50…
Zur Wirkung von Butazolidin im Intermedi�rstoffwechsel
1956
Butazolidin (Phenylbutazone) inhibits the oxidative decarboxylation of pyruvate and α-ketoglutarate in a final concentration of 10 mg-% (3,24 · 10−4 m). Data are presented suggesting that the β-ketothiolase is inhibited. The following enzymes or enzyme systems are not inhibited: The enzymes of the respiratory chain, the enzymes of the citric acid cycle with exception of α-ketoglutaric oxidase, the glycolysis of hexosediphosphate (slight inhibition), acetate thiokinase, sulfanilamid transacetylase, pyruvic decarboxylase from yeast, arginase, xanthine oxidase, and D-amino acid oxidase.