UMLS:C0406810 - FACTA Search

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Query: UMLS:C0406810 (NAME)
13,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Epidemiological studies have shown an association between ambient levels of particulate matter (PM) and increased mortality from cardiovascular diseases. However, the underlying mechanisms are still not clear. We hypothesised that PM, when translocated after inhalation, could affect vascular smooth muscle function. Therefore, total suspended particulate matter (TSP) was sampled and investigated for its ability to affect aortic muscle contraction. Both TSP and TSP supernatant (TSP-sup) induced a concentration-dependent relaxation of phenylephrine (PE)-precontracted aortic rings. Relaxation induced by 100 microg/ml TSP was 51.5 +/- 3.1% of total contraction. At 60 and 100 microg/ml, relaxation induced by TSP was significantly higher compared to TSP-sup. Ultrafine TiO2, used as a model to investigate the role of ultrafine particles, did not show an effect. Soluble iron, present in TSP suspensions, seems not to be involved, as chelating with deferoxamine did not affect TSP-induced relaxation. However, TSP effects were inhibited by Trolox, suggesting a role of oxidants. Nudation of aortic rings showed that effects of TSP were only partly endothelium-dependent, while preincubation with L-NAME increased TSP-induced relaxation. From these data, we conclude that both the particle core and soluble components of TSP can affect the smooth muscle function, leading to changes in the vascular contractile response.
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PMID:Ambient particulate matter induces relaxation of rat aortic rings in vitro. 1147 59

We examined the effect of NG-nitro-L-arginine methyl ester (L-NAME), a NOS inhibitor, on extracellular potassium ion concentration ([K+]o) and induced hydroxyl free radical (.OH) generation by an in vivo microdialysis technique. A flexibly mounted microdialysis technique was used to detect the generation of .OH in in-vivo rat hearts. The microdialysis probe was implanted in the left ventricular myocardium of anesthetized rats and tissue was perfused with Ringer's solution through the microdialysis probe at a rate of 1.0 microl/min. To measure the level of .OH, sodium salicylate in Ringer's solution (0.5 nmol/microl per min) was infused directly through a microdialysis probe to detect the generation of .OH as reflected by the nonenzymatic formation of 2,3-dihydroxybenzoic acid (2,3-DHBA). Induction of high-concentration [K+]o (20, 70 and 140 mM) significantly increased formation of .OH trapped as 2,3-DHBA in a concentration-dependent manner. However, the application of L-NAME (50 mg/kg, i.v.) and allopurinol, a xanthine oxidase inhibitor, abolished the [K+]o depolarization-induced .OH generation. Tyramine (1.0 mM) increased the level of 2,3-DHBA. However, the application of L-NAME did not change the level of 2,3-DHBA. On the other hand, pretreatment with allopurinol (10 mg/kg, i.v.) abolished the KCl- or tyramine-induced .OH generation. Moreover, when iron (II) was administered to [K+]o (70 mM)-pretreated animals, there was a marked increased in the level of 2,3-DHBA. However, the application of L-NAME was not related to a Fenton-type reaction via [K+]o depolarization-induced .OH generation. To examine the effect of L-NAME on ischemic/reperfused rat myocardium, the heart was subjected to myocardial ischemia for 15 min by occlusion by left anterior descending coronary artery branch (LAD). When the heart was reperfused, a marked elevation of the level of 2,3-DHBA was observed. However, L-NAME attenuated .OH generation by ischemic/reperfused rat heart. These results suggest that NOS inhibition is associated with a cardioprotective effect due to the suppression of [K+]o depolarization-induced .OH generation.
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PMID:Nitric oxide induces hydroxyl radical generation in rat hearts via depolarization-induced nitric oxide synthase activation. 1148 40

Nitric oxide (NO) has been proved to be a mediator of hypoxic injury in renal proximal tubules (PT), but its effect on iron-induced cytotoxicity has remained little known. In this study, we observed the relationship between NO production and lactate dehydrogenase (LDH) release in primary proximal tubular epithelia co-incubated with different doses of NTA-Fe and lipopolysaccharide (LPS) alone or in combination. NO production was monitored by NO2 concentration in supernatants based on the Griess reaction; while the semi-quantitative RT-PCR was applied to detect the inducible nitric oxide synthase (iNOS) mRNA level induced by NTA-Fe and LPS together. In addition, experimental groups were subjected to reactive oxygen species (ROS) scavengers to determine the impact of the interaction between NO and ROS on iron-mediated cytotoxicity. After a 12-h co-incubation, we found that NTA-Fe increased both LDH release and NO2(-) production in a dose-dependent manner (P < 0.001). The level of iNOS mRNA induced by LPS was enhanced by 500 microM NTA-Fe (P < 0.01), lower or higher concentrations had no effect. However, the supernatantNO2(-) level in the same group did not change significantly (P > 0.05) although tubular injury was aggravated (P < 0.001). The addition of L-arginine increased LDH release from 25.05 +/- 8.36% in the iron group to 38.67 +/- 7.67% in iron plus LPS group (P < 0.05); concomitantly, L-NAME mitigated iron toxicity in LPS-treated PT (P < 0.05). Hydroxyl scavengers provided complete protection against iron-mediated cytotoxicity (P < 0.001), but the decrease of NO2(-) production was only significant in the LPS-treated group. In contrast, SOD was partially effective in the LPS group (P < 0.05) whereas the NO2(-) level in the supernatant was inversely raised (P < 0.05). GSH had no effect on either iron toxicity or NO2(-) production. Thus, we conclude that NO can exacerbate the cytotoxicity caused by NTA-Fe in cultured proximal tubular epithelia, but NO is not the only factor. NTA-Fe could enhance the upregulation of iNOS transcription induced by LPS in a specific concentration range, and its regulation of NO production might also involve a post-transcription mechanism. The hydroxyl group is the major mediator in our model and the pro-oxidant role of NO is probably due to its ability to promote the Fenton reaction and form both ONOO(-) and *OH via its interaction with ROS.
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PMID:Effect of nitric oxide on iron-mediated cytotoxicity in primary cultured renal proximal tubules. 1174 4

The inhibition of nitric oxide (NO) synthesis by chronic administration of NG-nitro-l-arginine methyl ester (l-NAME) in rats is responsible for systemic hypertension. However, the mechanisms involved in this hypertension remain unclear. The effects of chronic l-NAME on kidney and blood NO production were studied in rats in a state of endotoxic shock due to lipopolysaccharide (LPS). A nitric oxide spin trapping technique using electron spin resonance (ESR) spectroscopy has been used to identify and measure the production of NO in the kidney. This method is based on the trapping of nitric oxide by a metal-chelator complex consisting of N-methyl-d-glucamine dithiocarbamate (MGD) and reduced iron (Fe2+) forming a water-soluble NO-FeMGD complex detected by ESR. After LPS injection (14 mg/kg, IV, 6 h before the sacrifice) to rats pretreated with l-NAME (10 mg/kg/d over 14 days), the NO-FeMGD complex was evaluated in the kidney (arbitrary units [AU]/g of kidney) and the density of polynuclear neutrophils was counted by light microscopy. Chronic inhibition of NO synthase by l-NAME, a nonspecific inhibitor, was responsible for a decrease of the NO-FeMGD complex levels in the kidney (24.9 +/- 1.6 AU versus 13.8 +/- 1.3 AU). LPS administration was responsible for a large increase in both NO-FeMGD complex and neutrophil levels in the kidney of normotensive rats (332.6 +/- 12.8 AU versus 24.9 +/- 1.6 AU for NO-FeMGD complex and 1.36 +/- 0.41 versus 0.11 +/- 0.03 for neutrophils). Conversely, LPS administration in hypertensive, l-NAME-pretreated rats was linked to a smaller increase in the NO-FeMGD complex (85.1 +/- 7.9 AU versus 332.6 +/- 12.8 AU) and a larger increase in glomerular neutrophils (2.48 +/- 0.36 versus 1.36 +/- 0.41) compared with normotensive rats. These results are in agreement with a direct implication of NO during LPS-and l-NAME-induced kidney injuries.
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PMID:Intrarenal detection of nitric oxide using electron spin resonance spectroscopy in hypertensive lipopolysaccharide-treated rats. 1207 72

The aim of the present study was to explore the effect of nitric oxide (NO) on iron-induced toxicity in rat hearts. Langendorff perfused rat heart and enzymatically isolated cardiomyocytes were used. It was shown that lipophilic Fe-HQ reduced the contractile amplitude, velocity and end-diastolic cell length in the cardiomyocyte, while the left ventricular developed pressure (LVDP), +/-dp/dt(max), heart rate and coronary flow showed biphasic alterations, which increased in the first 2 min and then was followed by a decline in isolated perfused rat heart; the contents of lactate dehydrogenase (LDH) and creatine kinase (CK) in the coronary effluent and the malondialdehyde (MDA) in the myocardium were increased. L-arginine (L-Arg), an NO precursor, reduced the contractile amplitude and end-diastolic cell length in the cardiomyocyte; but reversibly increased LVDP, +/-dp/dt(max), and coronary flow in isolated perfused rat heart. Pretreatment with L-Arg aggravated the Fe-HQ-induced decrease in contractile amplitude, velocity and end-diastolic cell length in the cardiomyocyte; LVDP, +/-dp/dt(max), heart rate and coronary flow were significantly reduced in the perfused heart, and the levels of LDH and CK increased in the coronary effluent. In contrast, the NOS inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) blocked the Fe-HQ induced change in contractile amplitude, velocity and end-diastolic cell length in the cardio- myocyte; it inhibited the decrease in LVDP, LVEDP and +/-dp/dt(max), and reduced the LDH and CK. Removing endothelial cells in coronary vessels attenuated the increase in LVDP and +/-dp/dt(max) at the beginning of Fe-HQ perfusion. It is suggested that L-Arg aggravates the iron-induced cardiac dysfunction, NO can mediate the iron-induced toxicity in heart, and endothelial cells in coronary vessels play an important role in the early stage of the effect of iron.
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PMID:[Role of nitric oxide in iron-induced toxicity in rat hearts]. 1219 77

To explore the role of nitric oxide (NO) in the pathogenesis and effect on regulation of iron metabolism in anemia of chronic disease (ACD) and provide experimental evidence for prevention and treatment of ACD. On the basis of traditional animal model of rheumatoid arthritis, an ACD rat model was established by repeated injection of Freund's complete adjuvant. The relationship between NO concentration and iron metabolism was observed in ACD rats with and without NO synthase inhibitor, L-NAME, (N omega-nitro-L-arginine methyl ester L-NAME). The results showed that anemia was induced in the rat model. In the ACD group, NO concentration and NO synthase activity in serum increased; iron, total iron binding capacity (TIBC) and transferrin saturation (TS) in serum and ferritin in erythrocytes (rFn) decreased; transferrin receptor (TfR) and iron in bone marrow cells decreased; ferritin in serum and iron in liver increased and meanwhile the acotinase activity in liver decreased. After administration of L-NAME, anemia was improved, when NO, NO-synthase activity, liver iron and serum ferritin decreased, but serum iron, TS, TIBC, rFn, TfR, iron in marrow cells and liver acotinase activity elevated. The levels of parameters for iron metabolism in ACD + L-NAME group were situated between ACD and control groups. It is concluded that NO plays an important role in pathogenesis of ACD and influences the regulation of iron in ACD. Decrease of NO level as early as possible will benefit to block the development of anemia, that will provide a new strategy of therapy for ACD.
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PMID:[Effect of nitric oxide on iron metabolism in rats with anemia of chronic disease]. 1296 68

This minireview describes the practical use of assay systems to detect nitric oxide (NO) by electron paramagnetic resonance (EPR) spectroscopy for evaluation of endothelial functions. The iron(II)-dithiocarbamate complexes, such as iron(II)-(N-methyl-D-glucamine dithiocarbamate), are commonly used in EPR detection of NO both in vivo and in vitro. However, due to their redox activity, these complexes have some drawbacks that limit their usefulness for the detection of NO. On the other hand, the measurement of hemoglobin-NO adduct (HbNO) in whole blood by the EPR method seems relevant for the assessment of systemic NO levels. However, ceruloplasmin and an unknown radical species overlapping the same magnetic field as that of HbNO, which makes it physically impossible to measure small amounts of HbNO. Thus, to reveal the EPR spectrum of HbNO, we developed the EPR signal subtraction method, which is based on the computer-assisted subtraction of the digitized EPR spectrum of HbNO-depleted blood from that of the sample blood using software. Using this technique, we succeeded in measuring the steady blood HbNO level as an index of NO by the EPR HbNO signal subtraction method. We also demonstrated that temocapril reduces abnormalities of NO dynamics in the L-NAME (N(omega)-nitro-L-arginine-methylester)-induced endothelial dysfunction of rats using the EPR HbNO signal subtraction method.
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PMID:New methods to evaluate endothelial function: Evaluation of endothelial function by hemoglobin-nitric oxide complex using electron paramagnetic resonance spectroscopy. 1473 11

Sphingolipid ceramide (N-acetylsphingosine), a bioactive second messenger lipid, was shown to activate reactive oxygen species (ROS), mitochondrial oxidative damage, and apoptosis in neuronal and vascular cells. The proapoptotic effects of tumor necrosis factor-alpha, hypoxia, and chemotherapeutic drugs were attributed to increased ceramide formation. Here we investigated the protective role of nitric oxide (.NO) during hydrogen peroxide (H(2)O(2))-mediated transferrin receptor (TfR)-dependent iron signaling and apoptosis in C(2)-ceramide (C(2)-cer)-treated bovine aortic endothelial cells (BAECs). Addition of C(2)-cer (5-20 microm) to BAECs enhanced .NO generation. However, at higher concentrations of C(2)-cer (> or =20 microm), .NO generation did not increase proportionately. C(2)-cer (20-50 microm) also resulted in H(2)O(2)-mediated dichlorodihydrofluorescein oxidation, reduced glutathione depletion, aconitase inactivation, TfR overexpression, TfR-dependent uptake of (55)Fe, release of cytochrome c from mitochondria into cytosol, caspase-3 activation, and DNA fragmentation. N(w)-Nitro-l-arginine methyl ester (l-NAME), a nonspecific inhibitor of nitricoxide synthases, augmented these effects in BAECs at much lower (i.e. nonapoptotic) concentrations of C(2)-cer. The 26 S proteasomal activity in BAECs was slightly elevated at lower concentrations of C(2)-cer (< or =10 microm) but was greatly suppressed at higher concentrations (>10 microm). Intracellular scavengers of H(2)O(2), cell-permeable iron chelators, anti-TfR receptor antibody, or mitochondria-targeted antioxidant greatly abrogated C(2)-cer- and/or l-NAME-induced oxidative damage, iron signaling, and apoptosis. We conclude that C(2)-cer-induced H(2)O(2) and TfR-dependent iron signaling are responsible for its prooxidant and proapoptotic effects and that .NO exerts an antioxidative and cytoprotective role.
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PMID:Ceramide-induced intracellular oxidant formation, iron signaling, and apoptosis in endothelial cells: protective role of endogenous nitric oxide. 1510 32

With increasing use of genetically modified mice to study endothelial nitric oxide (NO) biology, methods for reliable quantification of vascular NO production by mouse tissues are crucial. We describe a technique based on electron paramagnetic resonance (EPR) spectroscopy, using colloid iron (II) diethyldithiocarbamate [Fe(DETC)2], to trap NO. A signal was seen from C57BL/6 mice aortas incubated with Fe(DETC)2, that increased 4.7-fold on stimulation with calcium ionophore A23187 [3.45+/-0.13 vs 0.73+/-0.13au (arbitrary units)]. The signal increased linearly with incubation time (r(2) = 0.93), but was abolished by addition of N(G)-nitro-l-arginine methyl ester (L-NAME) or endothelial removal. Stimulated aortas from eNOS knockout mice had virtually undetectable signals (0.14+/-0.06 vs 3.17+/-0.21 au in littermate controls). However, the signal was doubled from mice with transgenic eNOS overexpression (7.17+/-0.76 vs 3.37+/-0.43 au in littermate controls). We conclude that EPR is a useful tool for direct NO quantification in mouse vessels.
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PMID:EPR quantification of vascular nitric oxide production in genetically modified mouse models. 1515 95

The possible role of nitric oxide on the exercise-induced changes in bleomycin-detectable iron (BDI) in the liver, spleen, bone marrow cells and heart was investigated. Female Sprague-Dawley rats were randomly assigned to four groups: S1 (Sedentary), S2 (Sedentary + L-NAME [N-nitro-L-arginine methyl ester]), E1 (Exercise) and E2 (Exercise + L-NAME). Animals in the E1 and E2 swam for 2 h/day for 3 months. L-NAME in the drinking water (1 mg/ml) was administrated to rats in the S2 and E2 groups for the same period. At the end of the 3rd month, nitrite and nitrate (NOx), BDI and non-heme iron (NHI) contents in the liver, spleen, bone marrow cells and heart were measured. The ratio of BDI/NHI was calculated. The exercise induced a significant increase in NOx and BDI contents and/or BDI/NHI ratio in the spleen, bone morrow cells and heart. Treatment with L-NAME, an inhibitor of NOS, led to a significant decrease in NOx and an increase in BDI levels and BDI/NHI ratios in these tissues. The correlative analysis showed that there is significantly positive correlation between NOx levels and BDI contents and/or BDI/NHI ratios in the spleen, bone marrow cells and heart. These results suggest that the increased nitric oxide might be one of the reasons leading to the increased BDI levels in these tissues in the exercised rats. In contrast to the above tissues, in the liver, exercise led to a significant decrease rather than increase in BDI levels and BDI/NHI ratios with a significant increase in NOx contents. Treatment with L-NAME led to a significant increase in BDI levels and BDI/NHI ratios and a decrease in NOx contents in the tissue. These findings plus the results reported by others imply that nitric oxide might have an inhibitory effect on BDI in the liver.
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PMID:Nitric oxide inhibition decreases bleomycin-detectable iron in spleen, bone marrow cells and heart but not in liver in exercise rats. 1522 83

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