Search results for "Oxidation-Reduction"
showing 10 items of 689 documents
Antioxidant betalains from cactus pear (Opuntia ficus-indica) inhibit endothelial ICAM-1 expression.
2004
It has been suggested that some pigments would have antioxidant properties and that their presence in dietary constituents would contribute to reduce the risk of oxidative stress–correlated diseases. Among others, inflammatory response depends on redox status and may implicate oxidative stress. Vascular endothelial cells are a direct target of oxidative stress in inflammation. We have tested the impact of the free radical scavenger and antioxidant properties of betalains from the prickle pear in an in vitro model of endothelial cells. Here we show the capacity of betalains to protect endothelium from cytokine- induced redox state alteration, through ICAM-1 inhibition. KEYWORDS: endothelial …
Glyceraldehyde-3-phosphate dehydrogenase regulates endothelin-1 expression by a novel, redox-sensitive mechanism involving mRNA stability
2008
17 pages.-- PMID: 18809573 [PubMed].-- Printed version published on Dec 2008.
Organic Nitrate Therapy, Nitrate Tolerance, and Nitrate-Induced Endothelial Dysfunction: Emphasis on Redox Biology and Oxidative Stress
2015
Abstract Organic nitrates, such as nitroglycerin (GTN), isosorbide-5-mononitrate and isosorbide dinitrate, and pentaerithrityl tetranitrate (PETN), when given acutely, have potent vasodilator effects improving symptoms in patients with acute and chronic congestive heart failure, stable coronary artery disease, acute coronary syndromes, or arterial hypertension. The mechanisms underlying vasodilation include the release of •NO or a related compound in response to intracellular bioactivation (for GTN, the mitochondrial aldehyde dehydrogenase [ALDH-2]) and activation of the enzyme, soluble guanylyl cyclase. Increasing cyclic guanosine-3′,-5′-monophosphate (cGMP) levels lead to an activation of…
Biochemistry and pharmacology of novel anthranilic acid derivatives activating heme-oxidized soluble guanylyl cyclase.
2005
The heme-enzyme soluble guanylyl cyclase (sGC) is an ubiquitous NO receptor, which mediates NO downstream signaling by the generation of cGMP. We studied the mechanism of action of the anthranilic acid derivatives 5-chloro-2-(5-chloro-thiophene-2-sulfonylamino-N-(4-(morpholine-4-sulfonyl)-phenyl)-benzamide sodium salt (HMR1766) (proposed international nonproprietary name, ataciguat sodium) and 2-(4-chloro-phenylsulfonylamino)-4,5-dimethoxy-N-(4-(thiomorpholine-4-sulfonyl)-phenyl)-benzamide (S3448) as a new class of sGC agonists. Both compounds activated different sGC preparations (purified from bovine lung, or crude from human corpus cavernosum) in a concentration-dependent and quickly reve…
Enzymatically modified nonoxidized low-density lipoprotein induces interleukin-8 in human endothelial cells: role of free fatty acids.
2002
Background— Treatment of low-density lipoprotein (LDL) with a protease and cholesterolesterase transforms the lipoprotein to an entity that resembles lipoprotein particles in atherosclerotic lesions, which have a high content of free cholesterol, reflecting extensive de-esterification in the intima. Because de-esterification would occur beneath the endothelium, we examined the effects of enzymatically modified LDL (E-LDL) on cultured endothelial cells. Methods and Results— Incubation of endothelial cells with E-LDL provoked selective accumulation of interleukin (IL)-8 mRNA and production of the cytokine. Chemical analyses and depletion experiments indicated that the effect was caused by th…
Solvent-Enhanced Diastereo- and Regioselectivity in the PdII-Catalyzed Synthesis of Six- and Eight-Membered Heterocycles viacis-Aminopalladation
2009
The Pd(II)-catalyzed intramolecular oxidative cyclization of tosyl-protected cis- and trans-N-allyl-2-aminocyclohexanecarboxamides was examined, and efficient syntheses of cyclohexane-fused pyrimidin-4-ones and 1,5-diazocin-6-ones were developed. In the course of the research, a marked solvent effect was observed on both the regio- and diastereoselectivity. Additionally, a novel Pd(II)-mediated domino oxidation, oxidative amination reaction was discovered. Our experimental and theoretical findings suggest that the reactions proceed via a cis-aminopalladation mechanism.
Supplementation with cactus pear (Opuntia ficus-indica) fruit decreases oxidative stress in healthy humans: a comparative study with vitamin C.
2004
Background: Cactus pear (Opuntia ficus-indica) fruit contains vitamin C and characteristic betalain pigments, the radical-scavenging properties and antioxidant activities of which have been shown in vitro. Objective: We investigated the effects of short-term supplementation with cactus pear fruit compared with vitamin C alone on total-body oxidative status in healthy humans. Design: In a randomized, crossover, double-treatment study, 18 healthy volunteers received either 250 g fresh fruit pulp or 75 mg vitamin C twice daily for 2 wk, with a 6-wk washout period between the treatments. Before (baseline) and after each treatment, 8-epiprostaglandin F2α (8-epi-PGF2α) and malondialdehyde in plas…
Contribution of vitamin A to the oxidation resistance of human low density lipoproteins.
1995
This study investigated the antioxidant contribution of vitamin A in protecting human low density lipoprotein (LDL) against copper-stimulated oxidation. The presence of small amounts of retinol (0.033 ± 0.012 nmol/mol LDL) and retinyl palmitate (0.036 ± 0.021 nmol/mol LDL) was routinely ascertained in the LDL. A single oral supplementation with 20,000 IU vitamin A caused a two- to three-fold increase of retinol and retinyl palmitate in the LDL isolated 8 h after the supplementation. In comparison to autologous-control LDL, vitamin A-enriched LDL were more resistant to oxidation, as expressed both by a clear delay in the onset of lipid peroxidation and by a reduction of the rate of conjugate…
FIA-fluorimetric determination of thiamine.
1990
A flow injection-fluorimetric determination of thiamine is reported. The procedure is based on the oxidation of the analyte with potassium hexacyanoferrate(III) immobilized on an anionic exchange resin; the fluorescence is monitored in aqueous basic solution. Concentrations of the vitamin of 0.1-4 ppm have been determined; the relative standard deviation was 1.8%. The injection rate was 28 samples/h. The influence of other substances and the determination of the drug in a pharmaceutical formulation are also reported.
α-Tocopherol Modulates Phosphatidylserine Externalization in Erythrocytes
2006
Objective— The aim of the present study was to assess the effect of α-tocopherol, the main vitamin E isomer on phosphatidylserine (PS) exposure at the surface of circulating erythrocytes, and to determine consequences on erythrocyte properties. Methods and Results— In vitro α-tocopherol enrichment of isolated erythrocytes significantly decreased PS externalization as assessed by lower Annexin V-fluorescein isothiocyanate labeling. Plasma phospholipid transfer protein (PLTP) transfers vitamin E, and both α-and γ-tocopherol accumulated in circulating erythrocytes from PLTP-deficient homozygous (PLTP −/− ) mice as compared with wild-type mice. In agreement with in vitro studies, vitamin E–enr…