Search results for "NITRITE"
showing 10 items of 227 documents
Redox signaling (cross-talk) from and to mitochondria involves mitochondrial pores and reactive oxygen species
2010
This review highlights the important role of redox signaling between mitochondria and NADPH oxidases. Besides the definition and general importance of redox signaling, the cross-talk between mitochondrial and Nox-derived reactive oxygen species (ROS) is discussed on the basis of 4 different examples. In the first model, angiotensin-II is discussed as a trigger for NADPH oxidase activation with subsequent ROS-dependent opening of mitochondrial ATP-sensitive potassium channels leading to depolarization of mitochondrial membrane potential followed by mitochondrial ROS formation and respiratory dysfunction. This concept was supported by observations that ethidium bromide-induced mitochondrial d…
Pyrazolobenzotriazinones Derivatives as COX Inhibitors: Synthesis Biological Activity and Molecular Modeling Studies
2010
Pyrazolylbenzotriazinones are endowed with structural analogy with the COX-2 selective inhibitor celecoxib. Considering that our research group has long been interested in the 3-pyrazolyl-substituted benzotriazinones as anti-inflammatory agents, six new pyrazolylbenzotriazinone derivatives 16a-c and 18a-c have been prepared by reacting the opportune ethyl 5-(2-aminobenzamido)-1-(pyridin-2-yl)-1H-pyrazole-4-carboxylate or 5-(2-aminobenzamido)-1-(pyridin-2-yl)-1H-pyrazole-4-carboxyic acid with sodium nitrite in glacial acetic acid. The biological studies revealed a good pharmacological profile for some pyrazolylbenzotriazinones and, in the case of the ethyl 5-(4-oxo-1,2,3-benzotriazin-3(4H)-y…
Rare Example of μ-Nitrito-1κ2O,O′:2κO Coordinating Mode in Copper(II) Nitrite Complexes with Monoanionic Tridentate Schiff Base Ligands: Structure, M…
2008
Three new copper(II) complexes, [CuL(1)(NO(2))](n) (1), [CuL(2)(NO(2))] (2), and [CuL(3)(NO(2))] (3), with three similar tridentate Schiff base ligands [HL(1) = 6-amino-3-methyl-1-phenyl-4-azahept-2-en-1-one, HL(2) = 6-amino-3-methyl-1-phenyl-4-azahex-2-en-1-one, and HL(3) = 6-diethylamino-3-methyl-1-phenyl-4-azahex-2-en-1-one] have been synthesized and characterized structurally and magnetically. In all three complexes, the tridentate Schiff base ligand and one oxygen atom of the nitrite ion constitute the equatorial plane around Cu(II), whereas the second oxygen atom of the nitrite ligand coordinates to one of the axial positions. In 1, this axially coordinated oxygen atom of the nitrite …
Oxidative stress upregulates the NMDA receptor on cerebrovascular endothelium.
2009
N-methyl-d-aspartate receptor (NMDA-R)-mediated oxidative stress has been implicated in blood-brain barrier (BBB) disruption in a variety of neuropathological diseases. Although some interactions between both phenomena have been elucidated, possible influences of reactive oxygen species (ROS) on the NMDA-R itself have so far been neglected. The objective of this study was to examine how the cerebroendothelial NMDA-R is affected by exposure to oxidative stress and to assess possible influences on BBB integrity. RT-PCR confirmed several NMDA-R subunits (NR1, NR2B-D) expressed in the bEnd3 cell line (murine cerebrovascular endothelial cells). NR1 protein expression after exposure to ROS was ob…
Phenylpropanoid and phenylisoprenoid metabolites from Asteraceae species as inhibitors of protein carbonylation.
2011
Abstract Three phenolic antioxidant and anti-inflammatory compounds: 7-methylaromadendrin, isoprenylhydroquinone glucoside, and 3.5-dicaffeoylquinic acid methyl ester, all isolated from Western Mediterranean Asteraceae species, have been studied for their inhibitory activity against protein carbonylation, a harmful post-translational modification of peptide chains associated with degenerative diseases. All compounds have proven to be effective, with 50% inhibitory concentration (IC 50 ) values in the micromolar range, against bovine serum albumin carbonylation caused by hypochlorite, peroxynitrite, and phorbol ester-induced leukocyte oxidative burst.
Sporogen, S14-95, and S-curvularin, three inhibitors of human inducible nitric-oxide synthase expression isolated from fungi.
2003
The induction of human inducible nitric-oxide synthase (iNOS) expression depends (among other factors) on activation of the signal transducer and activator of transcription 1 (STAT1) pathway. Therefore, the STAT1 pathway may be an appropriate target for the development of inhibitors of iNOS expression. HeLa S3 cells transiently transfected with a gamma-activated site (GAS)/interferon-stimulated response element-driven reporter gene construct were used as the primary screening system. Using this system, three novel inhibitors of interferon-gamma-dependent gene expression, namely, sporogen, S14-95, and S-curvularin, were isolated from different Penicillium species. These three compounds also …
Dysidotronic acid, a new sesquiterpenoid, inhibits cytokine production and the expression of nitric oxide synthase.
2001
In a previous study, we reported a new bioactive sesquiterpenoid, named dysidotronic acid, to be a potent, selective human synovial phospholipase A(2) inhibitor. Dysidotronic acid is a novel, non-complex manoalide analogue lacking the pyranofuranone ring. We now investigate the effect of this compound on cytokine, nitric oxide and prostanoid generation on the mouse macrophage cell line RAW 264.7, where it showed a dose-dependent inhibition with inhibitory concentration 50% values in the micromolar range. This effect was also confirmed in the mouse air pouch injected with zymosan. Dysidotronic acid inhibited the production of tumor necrosis factor alpha and interleukin-1 beta as well as the …
Evaluation of nitric oxide metabolites in a group of subjects with metabolic syndrome.
2012
Abstract Aim To evaluate the concentration of metabolites (NO2−, NO3−) of nitric oxide (NO) in metabolic syndrome (MS). Materials and methods We enrolled 106 subjects (45 women and 61 men) with MS of which 43 (14 women and 27 men) with diabetes mellitus and 63 (31 women and 32 men) without diabetes mellitus, and 54 subjects (19 women and 35 men) as control group. The nitric oxide metabolites (nitrite + nitrate = NOx) were evaluated employing the Griess reagent. Results In the whole group of MS subjects was evident, in comparison with control group, a significant increase in NOx. The same finding was also present between control group and diabetic subjects with MS and between control group a…
Genetic and Environmental Controls on Nitrous Oxide Accumulation in Lakes
2015
We studied potential links between environmental factors, nitrous oxide (N2O) accumulation, and genetic indicators of nitrite and N2O reducing bacteria in 12 boreal lakes. Denitrifying bacteria were investigated by quantifying genes encoding nitrite and N2O reductases (nirS/nirK and nosZ, respectively, including the two phylogenetically distinct clades nosZ(I) and nosZ(II)) in lake sediments. Summertime N2O accumulation and hypolimnetic nitrate concentrations were positively correlated both at the inter-lake scale and within a depth transect of an individual lake (Lake Vanajavesi). The variability in the individual nirS, nirK, nosZ(I), and nosZ(II) gene abundances was high (up to tenfold) a…
Real-time control strategy for nitrogen removal via nitrite in a SHARON reactor using pH and ORP sensors
2012
This paper presents a real-time control strategy for nitrogen removal via nitrite in a continuous flow SHARON reactor using on-line available and industrially feasible sensors (pH and ORP). The developed control strategy optimizes the length of aerobic and anoxic phases as well as the external carbon source addition. This strategy, implemented in a laboratory-scale SHARON reactor fed with synthetic wastewater and real dewatering sludge supernatant, was able to cope with step variations in influent flow rate and ammonium concentration. The main advantages of this control strategy over the traditional operation mode with fixed carbon source dosification and fixed length cycle operation were: …