Search results for "Peroxides"
showing 10 items of 162 documents
Effect of some hexahydroimidazo[1,2-c]pyrimidines in inflammatory responses involving leucocytes and macrophages.
2001
Abstract We have studied the effects of some hexahydroimidazo[1,2-c]pyrimidine derivatives (HIPs) on leucocyte functions in-vitro and we have assayed the anti-inflammatory activity of these compounds in two models of inflammation. All HIPs inhibited the human neutrophil degranulation process and superoxide generation at concentrations in the μM range. In mouse peritoneal macrophages stimulated with lipopolysaccharide, HIP-4 and HIP-5 inhibited nitrite production without affecting prostaglandin E2 (PGE2) accumulation. HIP-4 was also active in the zymosan-injected mouse air pouch model (at 100 nmol/pouch), with significant reductions in leucocyte migration and PGE2 and leukotriene B4 levels i…
Pro-oxidant activity of indicaxanthin from Opuntia ficus indica modulates arachidonate metabolism and prostaglandin synthesis through lipid peroxide …
2014
Macrophages come across active prostaglandin (PG) metabolism during inflammation, shunting early production of pro-inflammatory towards anti-inflammatory mediators terminating the process. This work for the first time provides evidence that a phytochemical may modulate the arachidonate (AA) metabolism in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, promoting the ultimate formation of anti-inflammatory cyclopentenone 15deoxy-PGJ2. Added 1 h before LPS, indicaxanthin from Opuntia Ficus Indica prevented activation of nuclear factor-κB (NF-κB) and over-expression of PGE2 synthase-1 (mPGES-1), but up-regulated cyclo-oxygenase-2 (COX-2) and PGD2 synthase (H-PGDS), with final product…
Cirrhotic patients with minimal hepatic encephalopathy have increased capacity to eliminate superoxide and peroxynitrite in lymphocytes, associated w…
2018
Patients with minimal hepatic encephalopathy (MHE) show increased oxidative stress in blood. We aimed to assess whether MHE patients show alterations in different types of blood cells in (a) basal reactive oxygen and nitrogen species levels; (b) capacity to metabolise these species. To assess the mechanisms involved in the altered capacity to metabolise these species we also analysed: (c) peroxynitrite formation and d) peroxynitrite reaction with biological molecules. Levels of reactive oxygen and nitrogen species were measured by flow cytometry in blood cell populations from cirrhotic patients with and without MHE and controls, under basal conditions and after adding generators of superoxi…
Chemi- and Bioluminescence of Cyclic Peroxides
2018
Bioluminescence is a phenomenon that has fascinated mankind for centuries. Today the phenomenon and its sibling, chemiluminescence, have impacted society with a number of useful applications in fields like analytical chemistry and medicine, just to mention two. In this review, a molecular-orbital perspective is adopted to explain the chemistry behind chemiexcitation in both chemi- and bioluminescence. First, the uncatalyzed thermal dissociation of 1,2-dioxetane is presented and analyzed to explain, for example, the preference for triplet excited product states and increased yield with larger nonreactive substituents. The catalyzed fragmentation reaction and related details are then exemplif…
Gp91phox-containing NAD(P)H oxidase increases superoxide formation by doxorubicin and NADPH
2006
Doxorubicin is a highly effective antineoplastic drug associated with a dose-dependent cardiotoxicity that may result in irreversible cardiomyopathy and heart failure. Gene variants of the superoxide-generating enzyme NAD(P)H oxidase have recently been associated with this phenotype. We investigated the mechanism of this association using lucigenin-enhanced chemiluminescence, spectrophotometry, electrochemical sensor, and electron paramagnetic resonance spectroscopy. Superoxide production was measured in female wild-type and NAD(P)H oxidase-deficient (gp91phox knockout) mice. The magnitude of the increase in superoxide production on the addition of doxorubicin was much higher in hearts of w…
Early mitochondrial dysfunction, superoxide anion production, and DNA degradation are associated with non-apoptotic death of human airway epithelial …
2002
It has been shown that bacterial exoproducts may induce airway epithelium injury. During the epithelial repair process, the respiratory epithelial cells no more establish tight junctional intercellular complexes and may be particularly susceptible to bacterial virulence factors. In this study, we analyzed the effect of Pseudomonas aeruginosa exotoxin A (ETA) at different periods of time and concentrations on 16 HBE 14o(-) human bronchial epithelial cells in culture conditions inducing a phenotype of repairing cells. ETA treatment for 24 and 48 h led to the killing of 40.0 +/- 5.7% and 79.0 +/- 1.4% of the cells, respectively, as determined by the dimethylthiazole 2,5 diphenyl tetrazolium br…
Hemostatic, inflammatory, and oxidative markers in pesticide user farmers
2016
Research Article; International audience; The aim of this work was to investigate inflammatory, oxidative, and thrombotic parameters as biomarkers in farmers exposed to pesticides. Fifty farmers using chemical pesticides and 60 unexposed control men participated in this study. The Mediterranean diet compliance, the duration of pesticide use, and personal protection for pesticides handling were recorded using self-administered questionnaires. Serum biochemical parameters, oxidant/antioxidant, inflammatory, and thrombosis markers were determined. Our findings showed oxidative stress reflected by an increase in malondialdehyde, carbonyl proteins and superoxide anion levels and a decrease in vi…
Ex Vivo Treatment with a Polyphenol-Enriched Cocoa Extract Ameliorates Myocardial Infarct and Postischemic Mitochondrial Injury in Normotensive and H…
2016
Our objective was to determine the effects of a polyphenol-enriched cocoa extract (PCE) on myocardial postischemic alterations in normotensive (Wistar rats, W) and spontaneously hypertensive rats (SHR). Isolated hearts were submitted to 110 min of perfusion or 20 min stabilization, 30 min global ischemia, and 60 min reperfusion (R). Other hearts were treated with PCE at the onset of R. Infarct size, the reduced glutathione (GSH), and the expression of phospho-Akt, P-GSK-3β, and P-eNOS were assessed. In isolated mitochondria, the Ca2+-mediated response of mitochondrial permeability transition pore (mPTP), membrane potential (δψm), and superoxide production were determined. PCE decreased infa…
Uncoupling of Endothelial Nitric Oxide Synthase in Perivascular Adipose Tissue of Diet-Induced Obese Mice
2015
Objective— The present study was conducted to investigate the contribution of perivascular adipose tissue (PVAT) to vascular dysfunction in a mouse model of diet-induced obesity. Approach and Results— Obesity was induced in male C57BL/6J mice with a high-fat diet for 20 weeks, and vascular function was studied with myograph. In PVAT-free aortas isolated from obese mice, the endothelium-dependent, nitric oxide–mediated vasodilator response to acetylcholine remained normal. In contrast, a clear reduction in the vasodilator response to acetylcholine was observed in aortas from obese mice when PVAT was left in place. Adipocytes in PVAT were clearly positive in endothelial nitric oxide synthase…
Carbon Monoxide Protects Against Ischemia-reperfusion Injury in Vitro via Antioxidant Properties
2012
Carbon monoxide (CO) is believed to mediate many of the cytoprotective effects attributed to the activation of heme oxygenase (HO-1), the enzyme responsible for CO production. Recently, the study of CO-releasing molecules (CO-RMs) has provided a new approach for the delivery of CO. In the present study, we examined whether the cardioprotective properties of CO-RM2 in isolated rat hearts subjected to an ischemia-reperfusion (I/R) sequence were associated with the presence of CO. In addition, the antioxidant properties of CO-RM2 were evaluated. In hearts pretreated with CO-RM2, the improvement in contractile function at the end of the reperfusion period after 20 min of global total ischemia w…