Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Exposure of cultured pulmonary artery endothelial cells to 95% O2 resulted in the following sequence of events: decrease in [3H]thymidine incorporation after 24 h; increase of intracellular glutathione (GSH) and loss of cellular protein after 48 h; increase of spontaneous and decrease of provoked prostacyclin formation as well as increased release of cellular LDH after 72 h. This oxygen toxicity model was used to study the following 2 questions. (1) What is the relative importance of the GSH redox cycle compared to catalase as antioxidative defense against hyperoxia? Endothelial cells were grown in selenium-depleted medium to inhibit glutathione peroxidase activity. Endothelial GSH biosynthesis was inhibited by buthionine sulfoximine. Catalase activity was reduced by aminotriazole. Endothelial cells with an impaired GSH redox cycle were easily killed by hyperoxia within 24 h, while inhibition of catalase did not enhance the susceptibility of endothelial cells to hyperoxia. (2) Can endothelial GSH content be increased by exogenous sulfhydryl reagents and does this result in an increase of endothelial cells' resistance to hyperoxia? Exogenous GSH, N-acetylcysteine, cysteine, and L-2-oxothiazolidine-4-carboxylate (L-2-oxo) increased intracellular GSH. All sulfhydryl reagents (with the exception of L-2-oxo) protected endothelial cells from hyperoxia. Concentrations of exogenous GSH and N-acetylcysteine that did not increase intracellular GSH reduced hyperoxia-induced endothelial cell injury. Thus the capacity of the GSH redox cycle rather than intracellular GSH levels or catalase determines endothelial cells' resistance to hyperoxia.
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PMID:Glutathione redox cycle is an important defense system of endothelial cells against chronic hyperoxia. 192 73

A differentiation-arrested primary cell culture model was used to examine the role of reactive oxygen species in the control of prostacyclin (PGI2) production in the perinatal rat lung. Coincubation of the lung cells with arachidonic acid (AA) and xanthine (X, 0.25 mM) plus xanthine oxidase (XO, 10 mU/ml) or with AA and glucose (25 mM) plus glucose oxidase (25 mU/ml) augmented the AA-induced PGI2 output. Superoxide dismutase (10 U/ml) did not alter the X + XO effect, whereas catalase (10 U/ml) eliminated both X + XO and glucose plus glucose oxidase effects. H2O2 (1-200 microM) showed a dose-related biphasic augmentation with peak stimulation at 20 microM. Catalase again blocked this effect, but dimethylthiourea, a hydroxyl radical scavenger, did not. A 20-min pretreatment of the cells with X + XO, glucose plus glucose oxidase, or H2O2, however, diminished the capacity of the cells to convert exogenous AA to PGI2. This pretreatment effect was also blocked by catalase. The responses were similar in lung cells obtained from day 20 rat fetuses (term = 22 days) and 1-day-old newborn rats. Lactate dehydrogenase release was not detected during treatment periods but increased significantly after exposure to reactive oxygen species.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of reactive oxygen species on prostacyclin production in perinatal rat lung cells. 265 89

The effects of homocysteine on the synthesis of arterial prostacyclin (PGI2) were investigated. Homocysteine at 10 mM and 1 mM concentration inhibited PGI2 synthesis from both exogenous and endogenous arachidonic acid. While concentrations of 100 microM and 1 microM stimulated PGI2 synthesis. Similar inhibitory effects of H2O2 on PGI2 synthesis were observed. High concentrations (100 microM and 500 microM) of H2O2 inhibited PGI2 production while low concentrations (1 microM) of H2O2 stimulated it. Catalase overcame the inhibitory effect of H2O2 (100 microM). Homocysteine induced O2 uptake and catalase inhibited the O2 uptake by homocysteine. Thus the inhibitory and stimulatory effect of homocysteine may be dependent on the oxidation of homocysteine and subsequent H2O2 generation.
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PMID:Peroxide mediated effects of homocysteine on arterial prostacyclin synthesis. 352 44

We have examined the effect of activated neutrophils on the release of prostacyclin (PGI2) from cultured endothelial cells by radioimmunoassay and thin layer chromatography of its stable metabolite, 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha). Phorbol myristate acetate-activated neutrophils induced a time- and dose-dependent release of 6-keto-PGF1 alpha from human and bovine endothelial cell monolayers, whereas phorbol myristate acetate alone and neutrophils alone did not. Pretreatment of the endothelial cells with aspirin prevented neutrophil-mediated 6-keto-PGF1 alpha release, indicating that it did not depend upon neutrophil-generated endoperoxides. Phorbol myristate acetate-activated neutrophils from a patient with chronic granulomatous disease failed to induce endothelial 6-keto-PGF1 alpha release. Addition of catalase but not of superoxide dismutase significantly reduced human and bovine endothelial 6-keto-PGF1 alpha release by phorbol myristate acetate-activated neutrophils. Catalase-inhibitable endothelial 6-keto-PGF1 alpha release was also observed after the addition of the hydrogen peroxide-generating system, glucose-glucose oxidase, to bovine and human endothelial cell monolayers. Bovine endothelial 6-keto-PGF1 alpha release induced by exogenously generated hydrogen peroxide was attenuated by the phospholipase inhibitor mepacrine, suggesting that hydrogen peroxide may act by triggering endothelial membrane phospholipase activation. The release of 6-keto-PGF1 alpha by enzymatically or neutrophil-generated hydrogen peroxide was not associated with endothelial cell lysis as assessed by 51Cr release. We conclude that exogenously generated hydrogen peroxide or a hydrogen peroxide-derived product mediates rapid nonlytic release of PGI2 from cultured endothelial cells.
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PMID:Role of hydrogen peroxide in the neutrophil-mediated release of prostacyclin from cultured endothelial cells. 637 74

Hydrogen peroxide (H2O2) is known to cause transient pulmonary vasoconstriction in isolated lungs perfused with a solution containing no blood components, by inducing vasoactive arachidonate metabolites such as thromboxane A2 (TXA2). However, the exact site of production of the vasoactive arachidonates in the lung tissue is unclear. Using isolated main pulmonary arterial rings obtained from male Sprague-Dawley rats (B.W. 300-350 g), we attempted to examine the arachidonate metabolism, especially that mediated by cyclooxygenase, in the vascular wall of pulmonary artery without endothelium. Changes in isometric tension were used to measure contraction or dilatation of the ring preparation. H2O2 caused transient contraction of the ring, which was treated previously with a solution containing a high concentration of potassium (20 mM). The contractile response was enhanced in parallel with the concentration of H2O2 in the presence or absence of endothelium. Catalase (1000 U/ml), a H2O2 scavenger, completely inhibited the response of the isolated ring (without endothelium) to H2O2. OKY-046 (10(-5) and 10(-4) M), a TXA2 synthetase blocker, partially attenuated the contractile response induced by H2O2. ONO-3708 (10(-5) M), a TXA2 and prostaglandin H2 receptor blocker, fully inhibited the vasoconstriction and caused relaxation of the ring without endothelium after addition of H2O2. Indomethacin (5 microM), a cyclooxygenase inactivator, completely inhibited both vasoconstriction and vasodilation of the denuded ring. H2O2 also induced the release of 6-keto-prostaglandin F1 alpha, a stable metabolite of the vasodilator, prostacyclin, from the pulmonary artery without endothelium.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Mechanism of constriction and dilatation of pulmonary artery induced by hydrogen peroxide]. 836 17

The goal of the present study was to determine whether oxygen-derived free radicals contribute to baroreceptor dysfunction in atherosclerosis. Baroreceptor activity was measured from the carotid sinus nerve during pressure ramps in isolated carotid sinuses of anesthetized rabbits. Rabbits fed a 0.5% to 1.0% cholesterol diet for 7.9 +/- 0.4 months (mean +/- SE; range, 5.5 to 10) developed atherosclerotic lesions in the carotid sinuses. Maximum baroreceptor activity measured at 140 mm Hg and the slope of the pressure-activity curve were reduced in atherosclerotic (n = 15) compared with normal (n = 13) rabbits (425 +/- 34 versus 721 +/- 30 spikes per second and 6.2 +/- 0.6 versus 10.8 +/- 0.8 spikes per second per mm Hg, respectively, P < .05). The level of activity was inversely related to plasma cholesterol concentration (r = .86, P < .001) and total cholesterol load (plasma concentration x duration of diet, r = .92). Mean arterial pressure was normal in both groups. Exposure of the carotid sinus to the free-radical scavengers superoxide dismutase (SOD) and catalase significantly increased maximum baroreceptor activity by 25 +/- 4% in atherosclerotic rabbits (n = 6) but caused only small and irreversible changes in activity in normal rabbits (n = 8). Catalase alone but not SOD also increased baroreceptor activity in atherosclerotic rabbits (n = 7). Exposure of the carotid sinus of normal rabbits to exogenous free radicals generated from the reaction between xanthine and xanthine oxidase inhibited baroreceptor activity in a dose-dependent and reversible manner (n = 8, P < .05). The inhibition of activity was attenuated by SOD and catalase but was not attenuated by the inhibitor of hydroxyl radical formation, deferoxamine. Neither restoration of baroreceptor activity in atherosclerotic rabbits by catalase nor inhibition of activity by xanthine/xanthine oxidase could be explained by changes in the carotid pressure-diameter relation or prostacyclin formation. These results indicate that oxidant stress inhibits baroreceptor activity and that endogenous oxyradicals produced in atherosclerotic carotid sinuses contribute to baroreceptor dysfunction.
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PMID:Oxygen-derived free radicals contribute to baroreceptor dysfunction in atherosclerotic rabbits. 883 4

The endothelium plays an important role in maintaining vascular homeostasis by synthesizing and releasing several endothelium-derived relaxing factors, such as prostacyclin, nitric oxide (NO), and the previously unidentified endothelium-derived hyperpolarizing factor (EDHF). In this study, we examined our hypothesis that hydrogen peroxide (H(2)O(2)) derived from endothelial NO synthase (eNOS) is an EDHF. EDHF-mediated relaxation and hyperpolarization in response to acetylcholine (ACh) were markedly attenuated in small mesenteric arteries from eNOS knockout (eNOS-KO) mice. In the eNOS-KO mice, vasodilating and hyperpolarizing responses of vascular smooth muscle per se were fairly well preserved, as was the increase in intracellular calcium in endothelial cells in response to ACh. Antihypertensive treatment with hydralazine failed to improve the EDHF-mediated relaxation. Catalase, which dismutates H(2)O(2) to form water and oxygen, inhibited EDHF-mediated relaxation and hyperpolarization, but it did not affect endothelium-independent relaxation following treatment with the K(+) channel opener levcromakalim. Exogenous H(2)O(2) elicited similar relaxation and hyperpolarization in endothelium-stripped arteries. Finally, laser confocal microscopic examination with peroxide-sensitive fluorescence dye demonstrated that the endothelium produced H(2)O(2) upon stimulation by ACh and that the H(2)O(2) production was markedly reduced in eNOS-KO mice. These results indicate that H(2)O(2) is an EDHF in mouse small mesenteric arteries and that eNOS is a major source of the reactive oxygen species.
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PMID:Hydrogen peroxide is an endothelium-derived hyperpolarizing factor in mice. 1113 74

Ca(2+)-activated K(+) channels (K(Ca)), in particular, the small and intermediate K(Ca) (SK(Ca) and IK(Ca), respectively) channels, are key players in endothelium-derived hyperpolarizing factor (EDHF)-mediated relaxation in small arteries. Hypertension is characterized by an endothelial dysfunction, possibly via reduced EDHF release and/or function. We hypothesize that during angiotensin II (14 days)-induced hypertension (ANG II-14d), the contribution of SK(Ca) and IK(Ca) channels in ACh-induced relaxations is reduced due to decreased expression of SK(Ca) and IK(Ca) channel proteins in rat small mesenteric arteries (MAs). Nitric oxide- and prostacyclin-independent vasorelaxation to ACh was similar in small MAs of sham-operated and ANG II-14d rats. Catalase had no inhibitory effects on these relaxations. The highly selective SK(Ca) channel blocker UCL-1684 almost completely blocked these responses in MAs of sham-operated rats but partially in MAs of ANG II-14d rats. These changes were pressure dependent since UCL-1684 caused a greater inhibition in MAs of 1-day ANG II-treated normotensive rats compared with ANG II-14d rats. Expression levels of both mRNA and protein SK3 were significantly reduced in MAs of ANG II-14d rats. The IK(Ca) channel blocker 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole (TRAM-34) resulted in comparable reductions in the relaxation responses to ACh in MAs of sham-operated and ANG II-14d rats. Relative mRNA expression levels of IK1 were significantly reduced in MAs of ANG II-14d rats, whereas protein levels of IK1 were not but tended to be lower in MAs of ANG II-14d rats. The findings demonstrate that EDHF-like responses are not compromised in a situation of reduced functional activity and expression of SK3 channels in small MAs of ANG II-induced hypertensive rats. The role of IK1 channels is less clear but might compensate for reduced SK3 activity.
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PMID:Reduced expression of SKCa and IKCa channel proteins in rat small mesenteric arteries during angiotensin II-induced hypertension. 1720

Oxidative stress is involved in pathogenesis of Raynaud's phenomenon (RP), a hallmark of systemic sclerosis (SSc). Frequent episodes of ischemia-reperfusion may lead to release of free radicals and enhanced lipid peroxidation reflected by elevated levels of malondialdehyde (MDA). The failure of native antioxidants (Catalase [CAT], Superoxide dismutase [SOD], and Ceruloplasmin [CP]) might be crucial in endothelial cells damage in RP. Iloprost (IL) synthetic prostacyclin analogue is currently used in the treatment of SSc patients with RP. The objectives of this study were to compare the serum levels of MDA and CP, CAT and SOD activity in red blood cells hemolysate in SSc patients compared to healthy controls; and to study the effect of 5-days IL infusions on MDA and CP levels, and CAT and SOD activity in SSc patients with RP. Twelve SSc patients were treated with 50 mug IL for 5 days. Blood samples were taken before and after day 1st and after day 5th of IL infusions. Levels of CAT were measured according to the Aebi's method; SOD, according to the Misra and Fridovich method; MDA, according to Slater's method; and CP, according to Ravin's method. Activities of CAT (p < 0.001) and SOD (p < 0.04) were significantly reduced; levels of CP (p < 0.006) and MDA (p < 0.06) were raised in SSc compared to controls. IL infusions caused reduction in MDA (p < 0.0001) levels and enhanced production of SOD (p < 0.006) and CAT (p < 0.003). The levels of CP did not change (p = 0.48). Oxidant status in SSc patients with RP is impaired. Therapy with IL led to normalization of antioxidant activity. We suggest that CAT may be a sensitive and reliable laboratory marker of oxidative stress severity in RP. We found that IL, in addition to its vasoactive properties, has a potential to activate inner antioxidant system. Activation of inner antioxidant activity may explain long-term effect of IL instead of its very short half-life time.
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PMID:Antioxidant status after iloprost treatment in patients with Raynaud's phenomenon secondary to systemic sclerosis. 1740 13

This study aimed to evaluate the protective role of ground raspberry seeds (RBS) as a source of polyphenols and essential fatty acids on blood plasma enzymatic antioxidant status, lipid profile, and endothelium-intact vasodilation during physiological and pathological conditions. Young normotensive Wistar-Kyoto rats (WKYs) and spontaneously hypertensive rats (SHRs) at ten weeks of age were fed with either a control diet or were supplemented with added 7% RBS for six weeks (n = 6). The main component of RBS was dietary fiber (64%) and the main polyphenols were ellagitannins (1.2%) and flavan-3-ols (0.45%). Irrespective of the rat model, ground RBS decreased liver enzyme aspartate aminotransferase (0.9-fold) and hydrogen peroxide scavenging capacity (Catalase, 0.9-fold). In supplemented SHRs, preincubation with inducible nitric oxide synthase (iNOS) inhibitor 1400W, nonselective cyclooxygenase (COX) inhibitor indomethacin, selective COX-2 inhibitor NS-398, prostacyclin (PGI2) synthesis inhibitor tranylcypromine (TCP), thromboxane receptor (TP) antagonist SQ-29548, thromboxane synthesis inhibitor furegrelate, and 20-HETE synthesis inhibitor HET0016 induced the same relaxant response to acetylcholine as in the nonsupplemented control group. In supplemented WKYs, atherogenic index was decreased (0.8-fold), while iNOS and COX-2-derived PGI2 increased acetylcholine-induced vasodilation. These effects of ground RBS may constitute a potential mechanism for preventing cardiovascular diseases.
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PMID:The Characterization of Ground Raspberry Seeds and the Physiological Response to Supplementation in Hypertensive and Normotensive Rats. 3249 5


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