Search results for "SCAVENGERS"
showing 10 items of 85 documents
Conversion of biliverdin to bilirubin by biliverdin reductase contributes to endothelial cell protection by heme oxygenase-1—evidence for direct and …
2009
Heme oxygenase-1 (HO-1) is highly protective in various pathophysiological states such as cardiovascular and neurodegenerative diseases. HO-1-derived bilirubin is an efficient scavenger of reactive oxygen and nitrogen species (RONS). It remains to determine whether conversion of biliverdin to bilirubin is an essential step for HO-1-conferred protection of endothelial cells. RONS scavenging activities of biliverdin versus bilirubin were assessed by different RONS generating systems and detection techniques. We also silenced the biliverdin reductase (BVR) or HO-1 gene in cultured primary human endothelial cells (HUVECs) and measured the effect on RONS formation upon stimulation with lipopolys…
Inhibition of leukocyte functions by the alkaloid isaindigotone from Isatis indigotica and some new synthetic derivatives.
2001
The alkaloid isaindigotone (1a) and seven derivatives have been synthesized to study their influence on several leukocyte functions and the generation of inflammatory mediators. Isaindigotone (1a) was found to be a scavenger of superoxide generated either by the hypoxanthine/xanthine oxidase system or stimulated human neutrophils. Isaindigotone (1a) and its acetylated derivative (1b) also inhibited 5-lipoxygenase activity and leukotriene B(4) production in these cells, whereas none of the compounds affected degranulation. In RAW 264.7 macrophages stimulated with lipopolysaccharide, synthetic derivatives exerted higher inhibitory effects on prostaglandin E(2) (PGE(2)) and nitric oxide (NO) g…
Antioxidant Profile of Mono-and Dihydroxylated Flavone Derivatives in Free Radical Generating Systems
1995
Abstract A number of free radical generating systems were used to investigate the antioxidant properties and structure-activity relationships of a series of monohydroxylated and dihydroxylated flavones. Ortho-dihydroxylated flavones showed the highest inhibitory activity on en zymic and non-enzymic microsomal lipid peroxidation as well as on peroxyl radical scavenging. Most flavones were weak scavengers of hydroxyl radical, while ortho-dihydroxylated flavones interacted with superoxide anion generated by an enzymic system or by human neutrophils. This series of compounds did not exert cytotoxic effects on these cells. Scavenging of superoxide and peroxyl radicals may determ ine the anti…
Oxidative stress triggers cytokinesis failure in hepatocytes upon isolation
2015
Primary hepatocytes are highly differentiated cells and proliferatively quiescent. However, the stress produced during liver digestion seems to activate cell cycle entry by proliferative/dedifferentiation programs that still remain unclear. The aim of this work was to assess whether the oxidative stress associated with hepatocyte isolation affects cell cycle and particularly cytokinesis, the final step of mitosis. Hepatocytes were isolated from C57BL/6 mice by collagenase perfusion in the absence and presence of N-acetyl cysteine (NAC). Polyploidy, cell cycle, and reactive oxygen species (ROS) were studied by flow cytometry (DNA, phospho-histone 3, and CellROX(®) Deep Red) and Western blott…
Mandarin Juice Improves the Antioxidant Status of Hypercholesterolemic Children
2008
Background: Oxidative stress has been linked to such degenerative diseases as atherosclerosis, and it has been suggested that increased dietary intake of antioxidants may reduce its progression. Objective: To determine the effect of mandarin juice consumption on biomarkers related to oxidative stress in hypercholesterolemic children. Materials and Methods: The diet of 48 children with plasma cholesterol >200 mg/dL and low-density lipoprotein cholesterol >130 mg/dL was supplemented for 28 days with 500 mL/day of pure (100%) mandarin juice (Citrus clementina Hort. ex Tan.). The composition of the mandarin juice was analyzed, and its antioxidant antiradical activity was evaluated in vitro. Mal…
Allopurinol has Immunomodulating Activity following Topical and Systemic Application in Experimental Autoimmune Uveitis
2001
PurposeAllopurinol has beneficial effects in the systemic treatment of lens-induced uveitis and experimental autoimmune uveitis (EAU). This is believed to be due to a reduction of oxidative tissue damage through its dose-dependent free radical scavenging ability, and to an immunomodulating effect. The purpose of this study was to demonstrate the immunological effects on the IgG-antibody repertoire in EAU after topical and systemic allopurinol and steroids.MethodsWe assigned 43 male Lewis rats to 6 different groups: healthy rats (BASE, n=3), EAU without therapy (CTRL, n=9); systemic treatment with allopurinol (ALSYS, n=9, 50 mg/kg body wt.i.v., given every three days for two weeks), topical …
Heme oxygenase-1: a novel key player in the development of tolerance in response to organic nitrates.
2007
Objective— Nitrate tolerance is likely attributable to an increased production of reactive oxygen species (ROS) leading to an inhibition of the mitochondrial aldehyde dehydrogenase (ALDH-2), representing the nitroglycerin (GTN) and pentaerythrityl tetranitrate (PETN) bioactivating enzyme, and to impaired nitric oxide bioactivity and signaling. We tested whether differences in their capacity to induce heme oxygenase-1 (HO-1) might explain why PETN and not GTN therapy is devoid of nitrate and cross-tolerance. Methods and Results— Wistar rats were treated with PETN or GTN (10.5 or 6.6 μg/kg/min for 4 days). In contrast to GTN, PETN did not induce nitrate tolerance or cross-tolerance as assess…
In vivo and in vitro antioxidant properties of furosemide
2003
The aim of this study was to investigate in vivo and in vitro antioxidant properties of furosemide. In vitro, human red blood cells were submitted to oxidative stress (AAPH), in absence or in presence of different concentrations of furosemide. Potassium efflux was measured in order to quantify the oxidative stress after the action of AAPH on red blood cells. Allophycocyanin assay was also used to investigate antioxidant capacities of furosemide. For the in vivo experiment, male Wistar rats were used. A control group (n = 5) was treated by a daily intraperitoneal injection of saline solution (0.2 ml); 2 other groups (J0 and J+) were treated for 7 days by one daily intraperitoneal injection o…
Oral N-acetylcysteine reduces bleomycin-induced lung damage and mucin Muc5ac expression in rats
2003
Oxidative stress is involved in the pathogenesis of pulmonary fibrosis, therefore antioxidants may be of therapeutic value. Clinical work indicates that N ‐acetylcysteine (NAC) may be beneficial in this disease. The activity of this antioxidant was examined on bleomycin-induced lung damage, mucus secretory cells hyperplasia and mucin Muc5ac gene expression in rats. NAC (3 mmol·kg−1·day−1) or saline was given orally to Sprague-Dawley rats for 1 week prior to a single intratracheal instillation of bleomycin (2.5 U·kg−1) and for 14 days postinstillation. NAC decreased collagen deposition in bleomycin-exposed rats (hydroxyproline content was 4,257±323 and 3,200±192 µg·lung−1 in vehicle- and NAC…
Attenuation by oralN-acetylcysteine of bleomycin-induced lung injury in rats
2001
Antioxidant therapy may be useful in diseases with impaired oxidant-antioxidant balance such as pulmonary fibrosis. This study examines the effect ofN-acetylcysteine (NAC) on bleomycin-induced lung fibrosis in rats.NAC (3 mmol·kg−1; oral) was given daily from 1 week prior to a single intratracheal instillation of bleomycin (2.5 U·kg−1) or saline, until 14 days postinstillation.NAC partially decreased the augmented collagen deposition in bleomycin-exposed rats (hydroxyproline content was 4,354±386 and 3,416±326 µg·lung−1in vehicle-treated and NAC-treated rats, respectively; p<0.05). The histological assessment using a semiquantitative score showed less collagen deposition and inflammatory…