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Nitrite
Kinds of Nitrite Terms modified by Nitrite Selected AbstractsInhalation of Amyl Nitrite and the Measurement of Left Ventricular Outflow Velocity: Studies in Normal, Young AdultsECHOCARDIOGRAPHY, Issue 2 2000BYRON F. VANDENBERG M.D. Amyl nitrite inhalation is useful in the identification of patients with provocable left ventricular (LV) outflow tract obstruction. However, there are no prospective studies that assess the normal change in LV outflow velocity during this intervention. Eighteen normal subjects (mean age, 34 ± 5 years; 9 men and 9 women) inhaled amyl nitrite during measurement of LV outflow velocity. Peak velocity increased from 109 ± 16 cm/s to 144 ± 24 cm/s (P < 0.001). There were no significant gender differences in velocity measurements at baseline or at peak. Our study provides prospective data that may be useful when evaluating young adults for LV outflow tract obstruction with Doppler echocardiography during amyl nitrite inhalation. [source] Electrochemical Preparation of Poly(acriflavine) Film-Modified Electrode and Its Electrolcatalytic Properties Towards NADH, Nitrite and Sulfur OxoanionsELECTROANALYSIS, Issue 9 2007Shen-Ming Chen Abstract Electrochemical polymerization of acriflavine (AF) was carried out onto glassy carbon electrodes (GCE) from the aqueous buffer solution containing 1.5×10,3,M AF monomer (pH,3.5) which produced a thin electrochemically active film. This is noted as poly(AF) film modified electrodes (PAF/GCE). This modified electrode was shown a stable reversible redox couple centered at +0.22,V in pH,3.5 buffer solutions. PAF/GCE was found to be more stable in acidic solutions and its formal potential was found to be pH dependent with a slope close to ,60,mV/pH. The electrochemical deposition kinetics of poly(AF) onto gold coated quartz crystal was studied by using electrochemical quartz crystal microbalance (EQCM) combined with cyclic voltammetry (CV). PAF/GCE was found be good mediator for electrochemical oxidation of reduced nicotinamide adenine dinucleotide (NADH) in pH,5 buffer solutions. The electrocatalytic oxidation of SO and electrocatalytic reduction of NO, SO and S2O were carried out at PAF/GCE electrode in acidic aqueous solutions. The electrocatalytic oxidation of NADH was also investigated by using amperometric method. [source] Ontogenic delays in effects of nitrite exposure on tiger salamanders (Ambystoma tigrinum tigrinum) and wood frogs (Rana sylvatica)ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2005Kerry L. Griffis-Kyle Abstract Under certain conditions, nitrite can be present in freshwater systems in quantities that are toxic to the fauna. I exposed wood frog (Rana sylvatica) and eastern tiger salamander (Ambystoma tigrinum tigrinum) embryos and young tadpoles and larvae to elevated concentrations of nitrite in chronic toxicity tests: 0, 0.3, 0.6, 1.2, 2.1, 4.6, and 6.1 mg/L NO2 -N, exposing individuals as both embryos and larvae. Nitrite caused significant declines in wood frog hatching success (3.4 mg/L NO2 -N, wood frog), and lower concentrations caused significant mortality during the early larval stages (4.6 mg/L NO2 -N, salamander; 0.5 mg/L NO2 -N, wood frog). Later tests exposing individuals to nitrite only after hatching showed that both wood frog and tiger salamander vulnerability to nitrite declined shortly after hatching. Hence, examining a single life-history stage, especially later in development, may miss critical toxic effects on organisms, causing the researcher potentially to underestimate seriously the ecological consequences of nitrite exposure. [source] TEMPO and Carboxylic Acid Functionalized Imidazolium Salts/Sodium Nitrite: An Efficient, Reusable, Transition Metal-Free Catalytic System for Aerobic Oxidation of AlcoholsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2009Cheng-Xia Miao Abstract An effective catalytic system comprising a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) functionalized imidazolium salt ([Imim-TEMPO]+,X,), a carboxylic acid substituted imidazolium salt ([Imim-COOH]+,X,), and sodium nitrite (NaNO2) was developed for the aerobic oxidation of aliphatic, allylic, heterocyclic and benzylic alcohols to the respective carbonyl compounds with excellent selectivity up to >99%, even at ambient conditions. Notably, the catalyst system could preferentially oxidize a primary alcohol to the aldehyde rather than a secondary alcohol to the ketone. Moreover, the reaction rate is greatly enhanced when a proper amount of water is present. And a high turnover number (TON 5000) is achieved in the present transition metal-free aerobic catalytic system. Additionally, the functionalized imidazolium salts are successfully reused at least four times. This process thus represents a greener pathway for the aerobic oxidation of alcohols into carbonyl compounds by using the present task-specific ionic liquids in place of the toxic and volatile additive, such as hydrogen bromide, bromine, or hydrogen chloride (HBr, Br2 or HCl), which is commonly required for the transition metal-free aerobic oxidation of alcohols. [source] Trace Water-Promoted Oxidation of Benzylic Alcohols with Molecular Oxygen Catalyzed by Vanadyl Sulfate and Sodium Nitrite under Mild ConditionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2009Zhongtian Du Abstract An inexpensive catalytic system consisting of vanadyl sulfate and sodium nitrite was developed for the oxidation of benzylic alcohols with molecular oxygen under mild conditions. Benzyl alcohols with various substitutions were efficiently converted to their corresponding aldehydes with high conversion and selectivity under 80,°C (e.g., 4-nitrobenzyl alcohol was smoothly oxidized to 4-nitrobenzyl aldehyde with 94% yield under 0.5,MPa of molecular oxygen). Halogen, noble metals, extra base or complicated ligands were avoided. Addition of a trace of water to this system before the reaction was crucial for the high efficiency. [source] TEMPO- tert -Butyl Nitrite: An Efficient Catalytic System for Aerobic Oxidation of AlcoholsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2009Xijun He Abstract A metal-free catalytic system consisting of 2,2,6,6-tetramethylpiperidine N -oxyl (TEMPO) and tert -butyl nitrite has been developed to activate molecular oxygen for the aerobic oxidation of alcohols. A variety of active and non-active alcohols were oxidized to their corresponding carbonyl compounds in high selectivity and yields. [source] Effect of inflammation on kidney function and pharmacokinetics of COX-2 selective nonsteroidal anti-inflammatory drugs rofecoxib and meloxicamJOURNAL OF APPLIED TOXICOLOGY, Issue 7 2008Sam Harirforoosh Abstract Chronic arthritis adversely affects glomerular function and nonsteroidal anti-inflammatory drugs (NSAIDs) reduce electrolyte urinary excretion. In addition, both acute and chronic inflammations may alter clearance of drugs. We studied (a) the effects of inflammation on the renal function and pharmacokinetics of rofecoxib and meloxicam; (b) whether inflammation could exacerbate reduced electrolytes excretion changes observed with NSAIDs; and (c) the influence of inflammation on distribution of these drugs into the kidney. Single oral doses of rofecoxib (10 mg kg,1), meloxicam (3 mg kg,1) or placebo were administered to normal or pre-adjuvant arthritic rats. Blood and urine samples were collected for the measurement of plasma nitrite, BUN and creatinine. The urinary excretion of sodium and potassium was also determined. Nitrite, BUN and plasma creatinine were increased starting on day 9 in the groups with inflammation. Sodium and potassium excretion rates were not affected by inflammation. Meloxicam did not alter the electrolyte excretion in any of the groups. Rofecoxib significantly decreased sodium and potassium excretion in normal rats and potassium excretion in inflamed rats. Inflammation significantly increased plasma concentrations of rofecoxib, but not meloxicam. The ratios of the kidney:plasma concentrations were not significantly altered by inflammation following either drug. Inflammation altered kidney function, demonstrated by increases in BUN and plasma creatinine. However, it did not influence the urinary electrolytes excretion. Since we have observed similar patterns of the effect of NSAIDs on kidney under healthy and inflammatory conditions, one may conclude that inflammation does not exacerbate the adverse effect. Copyright © 2008 John Wiley & Sons, Ltd. [source] Effects of Varying Levels of Vegetable Juice Powder and Incubation Time on Color, Residual Nitrate and Nitrite, Pigment, pH, and Trained Sensory Attributes of Ready-to-Eat Uncured HamJOURNAL OF FOOD SCIENCE, Issue 6 2007J.J. Sindelar ABSTRACT:, Vegetable juice powder (VJP) and a starter culture containing Staphylococcus carnosus have been identified as necessary ingredients for the manufacture of uncured, no-nitrate/nitrite-added meat products with quality and sensory attributes similar to traditional cured products. The objectives of this study were to determine the effects of varying concentrations of VJP and incubation time (MIN-HOLD) on quality characteristics, including lipid oxidation, color, and cured meat pigment concentrations, of ham over a 90-d storage period, compare residual nitrate and nitrite content, and determine if differences exist in sensory properties of finished products. Four ham treatments (TRT) (TRT 1: 0.20% VJP, 0 MIN-HOLD; TRT 2: 0.20% VJP, 120 MIN-HOLD; TRT 3: 0.35% VJP, 0 MIN-HOLD; TRT 4: 0.35% VJP, 120 MIN-HOLD) and a sodium nitrite-added control (C) were used for this study. No differences (P > 0.05) were observed between TRTs and C for CIE L*, a*, b*, and cured color measured by reflectance ratio. Lipid oxidation (TBARS) for combined TRTs and C revealed little change over time while the C had less (P < 0.05) lipid oxidation than TRTs 2 and 4 for combined days. No differences (P > 0.05) were reported for cured pigment concentration between TRTs and C. Trained sensory panel intensity ratings for ham and vegetable aroma, and flavor, color, and firmness showed that a high concentration (0.35%) of VJP resulted in the highest scores for undesirable vegetable aroma and flavor. Treatment combinations with a low concentration (0.20%) of VJP were comparable to the C for all sensory attributes. [source] Reduction of Carcinogenic N-Nitrosamines and Residual Nitrite in Model System Sausage by IrradiationJOURNAL OF FOOD SCIENCE, Issue 4 2002H. J. Ahn ABSTRACT Gamma irradiation was used to reduce the N-nitrosamines and residual nitrite in model system sausage during storage. Aerobic or vacuum packaged sausage was irradiated at 0, 5,10, 20, and 30 kGy. The residual nitrite levels were significantly reduced by gamma irradiation, and, in vacuum packaging, the reduction was dose dependent. The N-nitrosodimethylamine of the sausage irradiated at 10 kGy or above reduced in aerobic packaging, while a dose of 20 kGy was needed in vacuum packaging. The N-nitrosopyrrolidine reduction was found at 20 and 30 kGy-irradiation. Results indicated that high dose irradiation (> 10 kGy) was needed to reduce the carcinogenic N-nitrosamine and nitrite levels in pork sausage during storage. [source] Acute Toxicity and Sublethal Effects of Nitrite on Selected Hematological Parameters and Tissues in Dark-banded Rockfish, Sebastes inermisJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2007In-Seok Park Acute toxicity and sublethal effects of nitrite in dark-banded rockfish, Sebastes inermis (83.3 ± 7.2 g), were studied under static conditions for a period of 96 h. The acute toxicity of nitrite evaluated for the 96-h lethal concentration (LC50) was 700 mg/L. The sublethal effects on selected hematological parameters of S. inermis, such as total erythrocyte count (TEC), hemoglobin, plasma glucose, and serum protein content, were measured after 0, 6, 12, 24, 48, 72, and 96 h of exposure to 0, 50, 100, 200, 400, and 700 mg/L of nitrite. Sublethal nitrite caused progressive reduction in the TEC, hemoglobin, and serum protein content in fish depending on the nitrite concentration and exposure period. The 96-h exposure resulted in a 14,42% reduction in TEC and 25,33% reduction in hemoglobin content for 100,700 mg/L of nitrite compared to the control. A dose-related reduction in plasma glucose (25.7,34.2%) was observed for concentrations of 200,700 mg/L of nitrite during 48 h of exposure, followed by an increase through 96 h. A significant reduction in serum protein (7.3,12.6%) was observed for 200,700 mg/L of nitrite after 96 h of exposure. Abnormal histological changes in skin, gill, liver, and kidney tissue were observed in fish exposed to 700 mg/L of nitrite after 96 h of exposure compared to the control. Although no mortality of S. inermis occurred at 500 mg/L of nitrite, all hematological parameters adversely responded to a nitrite dose of 200 mg/L for 96 h. These results showed that although acute toxicity concentration of nitrite in S. inermis is higher than 700 mg/L, sublethal concentrations of nitrite also negatively affect hematological parameters. [source] Acute and Chronic Effects of Nitrite on White Shrimp, Litopenaeus vannamei, Cultured in Low-Salinity Brackish WaterJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 3 2004Amit Gross The marine white shrimp Litopenaeus vannamei is widely cultured. Recently, farmers have begun to culture this shrimp in low-salinity brackish water (< 6 g/L). The intensification of shrimp culture often results in occurrences of elevated nitrite concentration during the growing season. Nitrite is toxic to shrimp and exposure to high concentrations may cause retarded growth and mortalities. The current study was aimed at investigating the acute and chronic toxicity of nitrite to L. vannamei grown in low-salinity (2 g/L) brackish water. Studies of the 96-h EC50 and LC50 values of nitrite were performed to determine the acute toxicity, and an aquarium growth study (2 d post exposure to elevated nitrite concentrations) was conducted to evaluate the chronic effects of nitrite on shrimp production. The 96-h EC50 and LC50 values for juvenile L. vannamei grown in water of 2 g/L salinity was about 9 mg/L NO2 -N, suggesting a safe concentration for shrimp production in ponds to be less than 0.45 mgIL NO2 -N. Exposing shrimp to nitrite concentration of 4 mg/L for 2 d reduced their growth but did not affect their survival. [source] A thermoluminescence study of the effects of nitrite on photosystem II in spinach thylakoidsLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 3 2006Archna Sahay Abstract The site of action of nitrite on PS II was investigated by measuring the TL profile of nitrite-treated spinach thylakoid membranes. Three bands were observed in control, which were identified as the Q band (7°C), the B band (24°C) and the C band (57°C). In the presence of 20 mmol/L nitrite, the intensity of the Q band decreased, the B band upshifted to 46°C but the C band disappeared. The suppression of the Q band and the upshift of the B band suggested that nitrite caused inhibition at the water oxidizing complex. The effects of nitrite also remained the same in the presence of chloride. In case of ion-sufficient thylakoid membranes, nitrite decreased the Q band peak intensity and caused an upshift in the B band peak temperature. Nitrite showed similar effects in the presence of DCMU. This suggested that the site of action of nitrite is not at the acceptor side but at the donor side of PS II. The inhibition shown by nitrite has been found to be specific for nitrite anion. No other anions such as formate, fluoride or nitrate, were effective. Copyright © 2006 John Wiley & Sons, Ltd. [source] LDL and UV-oxidized LDL induce upregulation of iNOS and NO in unstimulated J774 macrophages and HUVECAPMIS, Issue 1 2009KARIN PERSSON Oxidized low-density lipoprotein (LDL) diminishes NO production from activated macrophages. The interaction between LDL and inactivated macrophages is neglected and controversial. This study examines the effect of LDL, 7-oxysterols and iron compounds on NO production in unstimulated J774 macrophages. J774 cells and human umbilical vein endothelial cells (HUVEC) were either incubated for 24 h with native LDL (LDL) or ultraviolet (UV)-oxidized LDL (UVoxLDL), in the absence or presence of an inducible nitric oxide synthase (iNOS)- or an endothelial constitutive nitric oxide synthase (eNOS)-inhibitor. J774 cells were also incubated with lipopolysaccharide (LPS), in the absence or presence of an iNOS- or an eNOS-inhibitor. Nitrite was analysed as a marker of NO production. The mRNA levels of iNOS were evaluated by reverse transcriptase polymerase chain reaction. LDL and UVoxLDL significantly increased NO production from unstimulated J774 macrophages. This increase in NO was accompanied by enhanced expression of iNOS mRNA, and was inhibited by the iNOS inhibitor. Furthermore, NO production was elevated and angiotensin-converting enzyme (ACE) activity was reduced in HUVEC following the exposure to LDL and UVoxLDL. In conclusion, LDL may serve as an important inflammatory activator of macrophages and HUVEC, inducing inducible nitric oxide production but diminishing ACE. After its oxidation, this function of LDL may be further enhanced and may contribute to the regulation and progression of atheroma formation. [source] Sildenafil Improves the Beneficial Haemodynamic Effects of Intravenous Nitrite Infusion during Acute Pulmonary EmbolismBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 4 2008Carlos A. Dias-Junior While previous studies have shown that sildenafil (an inhibitor of cGMP-specific phosphodiesterase type 5) or nitrite (a storage molecule for nitric oxide) produces beneficial effects during acute pulmonary embolism, no previous study has examined whether the combination of these drugs can produce additive effects. Here, we expand previous findings and examine whether sildenafil enhances the beneficial haemodynamic effects produced by a low-dose infusion of nitrite in a dog model of acute pulmonary embolism. Haemodynamic and arterial blood gas evaluations were performed in non-embolized dogs treated with saline (n = 4), and in embolized dogs (intravenous injections of microspheres) that received nitrite (6.75 µmol/kg intravenously over 15 min. followed by 0.28 µmol/kg/min.) and sildenafil (0.25 mg/kg over 30 min.; n = 8), or nitrite followed by saline (n = 8), or saline followed by sildenafil (n = 7), or only saline (n = 8). Plasma thiobarbituric acid-reactive substances (TBARS) concentrations were determined using a fluorometric method. Acute pulmonary embolism increased pulmonary artery pressure by ,24 mmHg. While the infusion of nitrite or sildenafil infusions reversed this increase by ,42% (both P < 0.05), the combined infusion of both drugs reversed this increase by ,58% (P < 0.05). Similar effects were seen on the pulmonary vascular resistance index. Nitrite or sildenafil alone produced no significant hypotension. However, the combined infusion of both drugs caused transient hypotension (P < 0.05). Both dugs, either alone or combined, blunted the increase in TBARS concentrations caused by acute pulmonary embolism (all P < 0.05). These results suggest that sildenafil improves the beneficial haemodynamic effects of nitrite during acute pulmonary embolism. [source] Paracoccus denitrificans for the effluent recycling during continuous denitrification of liquid foodBIOTECHNOLOGY PROGRESS, Issue 3 2010Nils Tippkötter Abstract Nitrate is an undesirable component of several foods. A typical case of contamination with high nitrate contents is whey concentrate, containing nitrate in concentrations up to 25 l. The microbiological removal of nitrate by Paracoccus denitrificans under formation of harmless nitrogen in combination with a cell retention reactor is described here. Focus lies on the resource-conserving design of a microbal denitrification process. Two methods are compared. The application of polyvinyl alcohol-immobilized cells, which can be applied several times in whey feed, is compared with the implementation of a two step denitrification system. First, the whey concentrate's nitrate is removed by ion exchange and subsequently the eluent regenerated by microorganisms under their retention by crossflow filtration. Nitrite and nitrate concentrations were determined by reflectometric color measurement with a commercially available Reflectoquant® device. Correction factors for these media had to be determined. During the pilot development, bioreactors from 4 to 250 mg·L,1 and crossflow units with membrane areas from 0.02 to 0.80 m2 were examined. Based on the results of the pilot plants, a scaling for the exemplary process of denitrifying 1,000 tons per day is discussed. © 2010 American Institute of Chemical Engineers Biotechnol. Prog. 2010 [source] Containment of Biogenic Sulfide Production in Continuous Up-Flow Packed-Bed Bioreactors with Nitrate or NitriteBIOTECHNOLOGY PROGRESS, Issue 2 2003Casey Hubert Produced water from the Coleville oil field in Saskatchewan, Canada was used to inoculate continuous up-flow packed-bed bioreactors. When 7.8 mM sulfate and 25 mM lactate were present in the in-flowing medium, H2S production (souring) by sulfate-reducing bacteria (SRB) was prevented by addition of 17.5 mM nitrate or 20 mM nitrite. Changing the sulfate or lactate concentration of the in-flowing medium indicated that the concentrations of nitrate or nitrite required for containment of souring decreased proportionally with a lowered concentration of the electron donor lactate, while the sulfate concentration of the medium had no effect. Microbial communities were dominated by SRB. Nitrate addition did not give rise to changes in community composition, indicating that lactate oxidation and H2S removal were caused by the combined action of SRB and nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB). Apparently the nitrite concentrations formed by these NR-SOB did not inhibit the SRB sufficiently to cause community shifts. In contrast, significant community shifts were observed upon direct addition of high concentrations (20 mM) of nitrite. Strains NO3A and NO2B, two newly isolated, nitrate-reducing bacteria (NRB) emerged as major community members. These were found to belong to the ,-division of the Proteobacteria, to be most closely related to Campylobacter lari, and to oxidize lactate with nitrate or nitrite as the electron acceptor. Thus the mechanism of microbial H2S removal in up-flow packed-bed bioreactors depended on whether nitrate (SRB/NR-SOB) or nitrite (SRB/NR-SOB as well as NRB) was used. However, the amount of nitrate or nitrite needed to completely remove H2S was dictated by the electron donor (lactate) concentration, irrespective of mechanism. [source] Nitrite, NO and hypoxic vasodilationBRITISH JOURNAL OF PHARMACOLOGY, Issue 7 2009Jason D Allen The ability to deliver oxygen and other nutrients to working tissues at a rate acutely matched to demand is the quintessential function of the cardiovascular system. Thus, an understanding of the biochemical mechanisms involved in hypoxic vasodilation remains a major goal in vascular biology. Nitric oxide, its metabolites, and oxidation status are recognized as playing important roles in this process. Previous work examining how nitrite can be converted to bioactive nitric oxide (NO) under hypoxic conditions has focused on the role of the red blood cell and haemoglobin. In a recent issue of the British Journal of Pharmacology, Pinder et al. demonstrate that plasma nitrite, in the absence of haemoglobin, is capable of increasing the maximal dilation of rabbit aortic rings under hypoxic conditions. Furthermore, they demonstrate that this relaxation can occur with or without the endothelium. This observation, even if it is only a small proportion of the relaxant activity of nitrite, highlights how NO metabolites may be involved in a variety of mechanisms of vessel control. [source] Renal Carcinogenicity of Concurrently Administered Fish Meal and Sodium Nitrite in F344 RatsCANCER SCIENCE, Issue 2 2000Fumio Furukawa The effects of long-term concurrent administration of powdered fish meal and sodium nitrite were examined in F344 rats. A total of 600, 6-week-old rats were divided into 6 male and 6 female groups, each consisting of 50 animals. Rats in groups 1,3 and 7,9 were respectively fed diets supplemented with 64%, 32% and 8% (basal diet) fish meal, and simultaneously given 0.12% sodium nitrite in their drinking water. Groups 4,6 and 10,12 were respectively given 64%, 32% and 8% fish meal and tap water. At the 104th week, all surviving animals were killed and examined histopathologically. Treatment with fish meal dose-dependently increased the incidences and multiplicities of atypical tubules, adenomas and renal cell carcinomas in sodium nitrite-treated males. Females were less susceptible than males for renal tumor induction. In males given the 64% fish meal diet alone, the incidence and multiplicity of atypical tubules were also significantly increased as compared with the 8% fish meal alone case. Nephropathy was apparent in fish meal-treated groups in a clear dose-dependent manner, irrespective of the sodium nitrite treatment, and was more prominent in males than in females. Dimethylnitrosamine was found in the stomach contents after 4-week treatment with 64% fish meal plus 0.12% sodium nitrite, at a level twice that in the 8% fish meal plus 0.12% sodium nitrite group. The results clearly indicate that concurrent administration of fish meal and sodium nitrite induces renal epithelial tumors. Further studies are required to elucidate how nephropathy and nitrosamines produced in stomach contents may contribute to the observed renal tumor induction. [source] ChemInform Abstract: TEMPO and Carboxylic Acid Functionalized Imidazolium Salts/Sodium Nitrite: An Efficient, Reusable, Transition Metal-Free Catalytic System for Aerobic Oxidation of Alcohols.CHEMINFORM, Issue 5 2010Cheng-Xia Miao Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Efficient Oxidation of Adamantanes by Sodium Nitrite with Molecular Oxygen in Trifluoroacetic Acid.CHEMINFORM, Issue 3 2007Osamu Onomura Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Efficient Oxidation of Cycloalkanols by Sodium Nitrite with Molecular Oxygen in Trifluoroacetic Acid.CHEMINFORM, Issue 5 2005Yoshihiro Matsumura Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Highly Efficient Procedure for Regeneration of Carbonyl Groups from Their Corresponding Oxathioacetals and Dithioacetals Using Sodium Nitrite and Acetyl Chloride in Dichloromethane.CHEMINFORM, Issue 23 2003Abu T. Khan Abstract For Abstract see ChemInform Abstract in Full Text. [source] Electrocatalytic Oxidation of Nitrite at Gold Nanoparticle- polypyrrole Nanowire Modified Glassy Carbon ElectrodeCHINESE JOURNAL OF CHEMISTRY, Issue 12 2009Jing Li Abstract A novel chemically modified electrode based on the dispersion of gold nanoparticles on polypyrrole nanowires has been developed to investigate the oxidation behavior of nitrite using cyclic voltammetry, differential pulse voltammetry and chronoamperometry techniques. The diffusion coefficient (D), electron transfer coefficient (,) and charge transfer rate constant (k) for the oxidation of nitrite were determined. The modified electrode exhibited high electrocatalytic activity toward the oxidation of nitrite. The catalytic peak current was found to be linear with nitrite concentrations in the range of 8.0×10,7,2.5×10,3 mol·L,1 with a detection limit of 1.0×10,7 mol·L,1 (s/n=3). The proposed method was successfully applied to the detection of nitrite in water samples with obtained satisfactory results. Additionally, the sensor also showed excellent sensitivity, anti-interference ability, reproducibility and stability properties. [source] Nitrites in induced sputum as a simple and cheap non-invasive marker of airway inflammation for asthmatic schoolchildrenPEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 5 2008Arturo Recabarren To determine if there are differences in the nitric oxide metabolites (nitrites) in sputum of patients with persistent asthma and healthy schoolchildren, we performed a case-control study in a tertiary care hospital in Arequipa, Perś. Nitrites in induced sputum samples were measured using the Griess assay in 30 persistent asthmatics (mean age of 10.1 yr) and 30 controls (mean age of 11.9 yr). The mean ± s.d. of nitrites among asthmatics was significantly higher than the controls (16.30 ± 8.6 vs. 10.25 ± 4.68 nmol/ml, respectively, p = 0.001). Moreover, the nitrite level in the sputum in children with severe persistent asthma was higher than in the level found in the moderate and mild asthmatics (32.83 ± 9.48 vs. 18.10 ± 1.96 vs. 11.84 ± 4.73 nmol/ml, respectively, p < 0.01 for linear trend). This study showed for the first time in children that asthmatics have significantly higher levels of nitrites in induced sputum than healthy controls and that the level of nitrite correlates with the severity of the asthma. Nitrite levels in sputum, a simple and cheap, non-invasive method, may be a good alternative to measure the severity of inflammation in asthmatic children. [source] Generation and Trapping of Cyclopropyldiazonium and Diazocyclopropane in the Nitrosation of Cyclopropylamine with Alkyl Nitrites.CHEMINFORM, Issue 52 2004Yu. V. Tomilov Abstract For Abstract see ChemInform Abstract in Full Text. [source] Induced sputum nitrites correlate with FEV1 in children with cystic fibrosisACTA PAEDIATRICA, Issue 5 2010N Anil Abstract Aim:, To determine the difference in the levels of nitrites in induced sputum of children with cystic fibrosis (CF) and controls. Furthermore, to evaluate the association between induced sputum nitrites and lung function in children with CF. Methods:, Nitrites, cell differentials, white blood cell count, were estimated in induced sputum of 20 children with CF and 10 age-matched healthy controls. Nitrites in induced sputum samples were measured using the Greiss assay. Lung function was ascertained by spirometry. Results:, We observed high levels of nitrites in CF (184.8 ± 11.07 ,M/L) versus controls (56.4 ± 5.7 ,M/L) (p < 0.01). A positive correlation between neturophil percent and nitrites, white blood cell count and nitrites (p < 0.05) in children with CF was observed. Sputum nitrites correlated negatively with FEV1 (p < 0.05) in children with CF. Conclusion:, Induced sputum nitrite could serve as a useful non invasive marker for assessing the degree of inflammation in the airways of children with CF. [source] Activator protein-1 signalling pathway and apoptosis are modulated by poly(ADP-ribose) polymerase-1 in experimental colitisIMMUNOLOGY, Issue 4 2004Basilia Zingarelli Summary Poly(ADP-ribose) polymerase-1 (PARP-1) is activated in response to DNA injury in the nucleus of eukaryotic cells and has been implicated in intestinal barrier dysfunction during inflammatory bowel diseases. In this study we investigated whether PARP-1 may regulate the inflammatory response of experimental colitis at the level of signal transduction mechanisms. Mice genetically deficient of PARP-1 (PARP-1,/,) and wild-type littermates were subjected to rectal instillation of trinitrobenzene sulphonic acid (TNBS). Signs of inflammation were monitored for 14 days. In wild-type mice, TNBS treatment resulted in colonic ulceration and marked apoptosis, which was associated with decreased colon content of the antiapoptotic protein Bcl-2, whereas the proapoptotic Bax was unchanged. Elevated levels of plasma nitrate/nitrite, metabolites of nitric oxide (NO), were also found. These inflammatory events were associated with activation of c-Jun-NH2 terminal kinase (JNK), phosphorylation of c-Jun and activation of the nuclear transcription factor activator protein-1 (AP-1) in the colon. In contrast, PARP-1,/, mice exhibited a significant reduction of colon damage and apoptosis, which was associated with increased colonic expression of Bcl-2 and lower levels of plasma nitrate/nitrite when compared to wild-type mice. Amelioration of colon damage was associated with a significant reduction of the activation of JNK and reduction of the DNA binding of AP-1. The data indicate that PARP-1 exerts a pathological role in colitis possibly by regulating the early stress-related transcriptional response through a positive modulation of the AP-1 and JNK pathways. [source] Cardiotoxicity of doxorubicin/paclitaxel combination in rats: Effect of sequence and timing of administrationJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 2 2004Sherif Y. Saad Abstract The higher incidence of cardiotoxicity of doxorubicin (DOX)/paclitaxel (PTX) combination compared with DOX alone remains to be a major obstacle against effective chemotherapeutic treatment. We investigated the effect of sequence and time interval between administration of both drugs on the severity of cardiotoxicity of the combination. Male Wistar rats were divided into seven groups. DOX was administeded intraperitoneally (ip) at a single dose of 5 mg kg,1 every other 2 days, 2 doses per week for a total cumulative dose of 20 mg kg,1. PTX was administered by an ip route at a dose of 20 mg kg,1 every other 2 days. Both drugs were injected either alone or sequentially in combination. In one case, DOX preceded PTX by 30 min and 24 h and in the other case, PTX preceded DOX by 30 min and 24 h. Cardiotoxicity was evaluated by both biochemical and histopathological examination, 48 h after the last DOX dose. DOX-induced cardiotoxicity was manifested by abnormal biochemical changes including marked increases in serum creatine phosphokinase isoenzyme (CK-MB), lactate dehydrogenase (LDH), glutathione peroxidase (GSH-Px), and aspartate aminotransferase (AST) activity levels. Myocardial tissue from DOX-treated rats showed significant increases in malondialdehyde (MDA) production and total nitrate/nitrite (NOx) levels, parallel with depletion of "endogenous antioxidant reserve," including GSH contents and GSH-Px activity level. PTX treatment produced significant changes in the biochemical parameters measured by a lower magnitude than those changes produced by DOX alone. Combination of both drugs resulted in aggravation of DOX-induced cardiotoxicity regardless the sequence and time interval between administration of either drug. Administration of PTX 30 min and 24 h after DOX treatment showed exaggeration of combination-induced cardiotoxicity compared with the reverse sequence. This exacerbation was manifested by much more pronounced changes in serum and cardiac tissue parameters measured. Histopathological examination of ventricles of rat's heart revealed that DOX treatment produced myo-cytolysis and myocardial necrosis. Administration of PTX following DOX treatment showed extensive myocardial necrosis compared with those rats treated with either DOX alone or the reverse sequence of administration. Moreover, rats treated with PTX 24 h after DOX treatment showed exaggeration of the combination-induced cardiotoxicity. In conclusion, PTX might synergistically aggravate DOX-induced cardiotoxicity. The effect might be much more pronounced with those rats treated with PTX 24 h after DOX treatment. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:78,86, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20012 [source] Dexamethasone inhibits lipopolysaccharide-induced hydrogen sulphide biosynthesis in intact cells and in an animal model of endotoxic shockJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 8b 2009Ling Li Abstract Dexamethasone (1 mg/kg, i.p.) administered either 1 hr before or 1 hr after E. coli lipopolysaccharide (LPS, 4 mg/kg, i.p.) in conscious rats inhibited the subsequent (4 hrs) rise in plasma cytokine (interleukin [IL]-1,, tumour necrosis factor [TNF]-,), nitrate/nitrite (NO×), soluble intercellular adhesion molecule-1 (sICAM-1) concentration and lung/liver myeloperoxidase activity indicative of an anti-inflammatory effect. Dexamethasone also reduced the LPS-evoked rise in plasma hydrogen sulphide (H2S) concentration, liver H2S synthesizing activity and expression of cystathionine , lyase (CSE) and inducible nitric oxide synthase (iNOS). Mifepristone (RU-486) inhibited these effects. Dexamethasone (1,10 ,M) reduced the LPS-evoked release of IL-1,, TNF-, and L-selectin, decreased expression of CSE and iNOS and diminished nuclear factor ,B (NF-,B)-DNA binding in isolated rat neutrophils. In contrast, NaHS (100 ,M) increased L-selectin release from rat neutrophils. Dexamethasone also reduced LPS-induced up-regulation of CSE in foetal liver cells. 6-amino-4-(4-phenoxyphenylethylamino) quinazoline (QNZ, 10 nM), a selective inhibitor of transcription via the NF-,B pathway, abolished LPS-induced up-regulation of CSE expression. We propose that inhibition of CSE expression and reduction in formation of the pro-inflammatory component of H2S activity contributes to the anti-inflammatory effect of dexamethasone in endotoxic shock. Whether H2S plays a part in the anti-inflammatory effect of this steroid in other forms of inflammation such as arthritis or asthma warrants further study. [source] Differential Central NOS-NO Signaling Underlies Clonidine Exacerbation of Ethanol-Evoked Behavioral ImpairmentALCOHOLISM, Issue 3 2010Tara S. Bender Background:, The molecular mechanisms that underlie clonidine exacerbation of behavioral impairment caused by ethanol are not fully known. We tested the hypothesis that nitric oxide synthase (NOS)-derived nitric oxide (NO) signaling in the locus coeruleus (LC) is implicated in this phenomenon. Methods:, Male Sprague,Dawley rats with intracisternal (i.c.) and jugular vein cannulae implanted 6 days earlier were tested for drug-induced behavioral impairment. The latter was assessed as the duration of loss of righting reflex (LORR) and rotorod performance every 15 minutes until the rat recovered to the baseline walk criterion (180 seconds). In a separate cohort, we measured p-neuronal NOS (nNOS), p-endothelial NOS (eNOS), and p-ERK1/2 in the LC following drug treatment, vehicle, or NOS inhibitor. Results:, Rats that received clonidine [60 Ig/kg, i.v. (intravenous)] followed by ethanol (1 or 1.5 g/kg, i.v.) exhibited synergistic impairment of rotorod performance. Intracisternal pretreatment with nonselective NOS inhibitor N, -nitro- l -arginine methyl ester (l -NAME, 0.5 mg) or selective nNOS inhibitor N -propyl- l -arginine (1 ,g) exacerbated the impairment of rotorod performance caused by clonidine,ethanol combination. Exacerbation of behavioral impairment was caused by l -NAME enhancement of the effect of ethanol, not clonidine. l -NAME did not influence blood ethanol levels; thus, the interaction was pharmacodynamic. LORR caused by clonidine (60 ,g/kg, i.v.),ethanol (1 g/kg, i.v.) combination was abolished by selective inhibition of central eNOS (l -NIO, 10 ,g i.c.) but not by nNOS inhibition under the same conditions. Western blot analyses complemented the pharmacological evidence by demonstrating that clonidine,ethanol combination inhibits phosphorylation (activation) of nNOS (p-nNOS) and increases the level of phosphorylated eNOS (p-eNOS) in the LC; the change in p-nNOS was paralleled by similar change in LC p-ERK1/2. NOS inhibitors alone did not affect the level of nitrate/nitrite, p-nNOS, p-eNOS, or p-ERK1/2 in the LC. Conclusions:, Alterations in NOS-derived NO in the LC underlie clonidine,ethanol induced behavioral impairment. A decrease in nNOS activity, due at least partly to a reduction in nNOS phosphorylation, mediates rotorod impairment, while enhanced eNOS activity contributes to LORR, elicited by clonidine,ethanol combination. [source] | ||||||||||||||||||||||||||||||||||||||||