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Segregation of nitric oxide synthase expression and calcium response to nitric oxide in adrenergic and noradrenergic bovine chromaffin cells

Oset-Gasque, M. J.; Vicente, S.; González, M. P.; Rosário, L. M.; Castro, E.
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
Português
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66.65%
Previous work has demonstrated that nitric oxide can be an important intracellular messenger in the regulation of neurosecretion in chromaffin cells. Since standard chromaffin cell cultures are mixed populations of noradrenaline and adrenaline producing cells, it would seem important to understand the functional differences between these individual components. The use of fluorescence imaging techniques for the recording of cytosolic calcium from single chromaffn cells together with the immunoidentification of individual cells with specific antibodies against tyrosine hydroxylase, N-phenyl ethanolamine methyl transferase and nitric oxide synthase, has allowed us to measure single-cell calcium responses in identified adrenergic, noradrenergic and nitrergic chromaffin cells, thus helping us to clarify the differential role of nitric oxide in the function of these chromaffin cell types. 53±2% of chromaffin cells were able to synthesize nitric oxide (nitric oxidesynthase-positive cells), these cells being mainly noradrenergic (82±2%). Results indicate that nitric oxide donors such as sodium nitroprusside, molsidomine and isosorbide dinitrate evoke [Ca2+]i increases in a 62±4% of chromaffin cells, the response to nitric oxide donors being between 30 and 50% of that of 20 [mu]M nicotine. Cells responding to nitric oxide donors were mainly adrenergic (68±5%) although 45±9% of noradrenergic cells also gave [Ca2+]i increasing responses. The distribution of nitric oxide responding cells between nitric oxide synthase-positive and negative was very similar in the whole population (63 ± 5 and 60 ± 7%...

A nitric oxide synthase inhibitor decreases 6-hydroxydopamine effects on tyrosine hydroxylase and neuronal nitric oxide synthase in the rat nigrostriatal pathway

GOMES, Margarete Zanardo; RAISMAN-VOZARI, Rita; BEL, Elaine A. Del
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
66.53%
There is evidence that nitric oxide plays a role in the neurotransmitter balance within the basal ganglia and in the pathology of Parkinson`s disease. In the present work we investigated in striatal 6-hydroxydopamine (6-OHDA) lesioned rats the effects of a nitric oxide synthase (NOS) inhibitor, NG-nitro-L-arginine (L-NOARG), given systemically on both the dopaminergic (DA) neuronal loss and the neuronal NOS cell density. We analyzed the DA neuronal loss through tyrosine hydroxylase immunohistochemistry (TH). The nitrergic system was evaluated using an antibody against the neuronal NOS (nNOS) isoform. Treatment with the L-NOARG significantly reduced 6-OHDA-induced dopaminergic damage in the dorsal striatum, ventral substantia nigra and lateral globus pallidus, but had no effects in the dorsal substantia nigra and in the cingulate cortex. Furthermore, L-NOARG reduced 6-OHDA-induced striatal increase, and substantia nigra compacta decrease, in the density of neuronal nitric oxide synthase positive cells. These results suggest that nitric oxide synthase inhibition may decrease the toxic effects of 6-OHDA on dopaminergic terminals and on dopamine cell bodies in sub-regions of the SN and on neuronal nitric oxide synthase cell density in the rat brain. (c) 2008 Elsevier B.V. All rights reserved.

Inhibition of in vivo leishmanicidal mechanisms by tempol: Nitric oxide down-regulation and oxidant scavenging

LINARES, Edlaine; GIORGIO, Selma; AUGUSTO, Ohara
Fonte: ELSEVIER SCIENCE INC Publicador: ELSEVIER SCIENCE INC
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
66.56%
Tempol (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy) has long been known to protect experimental animals from the injury associated with oxidative and inflammatory conditions. In the latter case, a parallel decrease in tissue protein nitration levels has been observed. Protein nitration represents a shift in nitric oxide actions from physiological to pathophysiological and potentially damaging pathways involving its derived oxidants such as nitrogen dioxide and peroxynitrite. In infectious diseases, protein tyrosine nitration of tissues and cells has been taken as evidence for the involvement of nitric oxide-derived oxidants in microbicidal mechanisms. To examine whether tempol inhibits the microbicidal action of macrophages, we investigated its effects on Leishmania amazonensis infection in vitro (RAW 264.7 murine macrophages) and in vivo (C57B1/6 mice). Tempol was administered in the drinking water at 2 mM throughout the experiments and shown to reach infected footpads as the nitroxide plus the hydroxylamine derivative by EPR analysis. At the time of maximum infection (6 weeks), tempol increased footpad lesion size (120%) and parasite burden (150%). In lesion extracts, tempol decreased overall nitric oxide products and expression of inducible nitric oxide synthase to about 80% of the levels in control animals. Nitric oxide-derived products produced by radical mechanisms...

Complexos de rutênio com nitrosil como agentes doadores de óxido nítrico. Aspectos químicos e físico-químicos de suas aplicações como agentes terapêuticos" ; Ruthenium complexes with nitrosil group as donnors agents of nitric oxide. Chemical and Physical aspects of its applications as therapeutical agents"

Bertolini, Wagner Luiz Heleno Marcus
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 10/08/2004 Português
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66.57%
A atividade do óxido nítrico na Química e Biologia não é completamente conhecida. Centenas de artigos são publicados por ano, somente sobre este assunto. Muito mais estudos necessitam ser feitos nesta área. Cientistas no campo da Biologia que queiram estudar como o óxido nítrico se comporta em diferentes sistemas necessitam de algum tipo de composto modelo que libera NO, para auxiliá-los em seus estudos farmacocinéticos. O óxido nítrico (NO) é tão importante que há um grande desejo da sociedade cientifica em obter compostos que possibilitem liberá-lo. Ele apresenta aplicações diversificadas. Investigando a cinética de liberação de NO, poderemos saber como o mesmo pode ser aplicado nas mais diversas atividades, tais como: controlar a relaxação cardiovascular, pressão sanguínea ou mesmo o desenvolvimento do câncer. Neste trabalho sintetizamos e caracterizamos cis-[RuCl(NO)(bpy)2](PF6)2 e trans-[RuCl(NO)(bpy)2](PF6)2. Os valores obtidos para o complexo cis-[RuCl(NO)(bpy)2](PF6)2 por voltametria cíclica foram: E1/2= 0,21 V vs Fe ;UV-vis(298nm,332nm); FTIR:νNO= 1930 cm-1 ; para o complexo trans-[RuCl(NO)(bpy)2](PF6)2 a voltametria cíclica apresentou E1/2= 0,19 V vs Fe ;UV-vis (298nm,312nm); FTIR:νNO= 1921 cm-1. O desenvolvimento de sistemas de liberação de NO a partir de complexos nitrosilos de rutênio podem ser discutidos com particular referencia ao produto de necessidade médica. Uma compreensão apropriada das propriedades da molécula doadora de NO...

Avaliação comparada qualitativa da participação do óxido nítrico no processo inflamatório crônico granulomatoso induzido pela inoculação de BCG; Comparative qualitative evaluation of the role of nitric oxide in chronic granulomatous inflammatory process induced by BCG inoculation

Maiorino, Fernando Corleto
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 17/09/2004 Português
Relevância na Pesquisa
66.57%
O óxido nítrico (NO) é um radical livre gasoso que participa de uma série de processos biológicos fisiológicos sendo produzido por enzimas denominadas óxido nítrico sintases (NOS). Diversos estudos vem demonstrando sua participação na resposta inflamatória crônica, na qual as células inflamatórias, com destaque para os macrófagos, são estimuladas a sintetizarem NOS, que por esse motivo são denominadas induzíveis (iNOS) e passam a produzir o óxido nítrico que vai atuar na modulação do processo. A fim de comprovar sua participação filogenética na resposta granulomatosa, utilizou-se como modelo experimental a inoculação de onco-BCG na musculatura de tilápias-do-Nilo (Oreochromys niloticus) e de girinos de rã touro-gigante (Rana catesbeiana), na região plantar de tartarugas ?red ear? (Trachemys scripta elegans) e no coxim plantar de hamsters sírios (Mesocricetus auratus). Fragmentos da lesão foram colhidos aos 14, 28 e 42 dias pós-inoculação, fixados em Carnoy por quatro horas, sendo em seguida transferidos para álcool 70o GL. Procedeu-se a confecção de preparados histopatológicos segundo métodos de rotina que foram corados pelo método da hematoxilina e eosina. Imunoistoquímica foi realizada para a verificação da produção de óxido nítrico indiretamente através da marcação da iNOS com anticorpos anti-iNOS humana biotinilados produzidos em coelhos. Observou-se em todos os animais desenvolvimento de granulomas que mostraram tendência a maior organização aos 42 dias; as características celulares foram semelhantes...

Acute and sustained effects of early administration of inhaled nitric oxide to children with acute respiratory distress syndrome.

Fioretto, José R; de Moraes, Marcos A; Bonatto, Rossano C; Ricchetti, Sandra M Q; Carpi, Mário F
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 469-474
Português
Relevância na Pesquisa
66.57%
OBJECTIVE: To determine the acute and sustained effects of early inhaled nitric oxide on some oxygenation indexes and ventilator settings and to compare inhaled nitric oxide administration and conventional therapy on mortality rate, length of stay in intensive care, and duration of mechanical ventilation in children with acute respiratory distress syndrome. DESIGN: Observational study. SETTING: Pediatric intensive care unit at a university-affiliated hospital. PATIENTS: Children with acute respiratory distress syndrome, aged between 1 month and 12 yrs. INTERVENTIONS: Two groups were studied: an inhaled nitric oxide group (iNOG, n = 18) composed of patients prospectively enrolled from November 2000 to November 2002, and a conventional therapy group (CTG, n = 21) consisting of historical control patients admitted from August 1998 to August 2000. MEASUREMENTS AND MAIN RESULTS: Therapy with inhaled nitric oxide was introduced as early as 1.5 hrs after acute respiratory distress syndrome diagnosis with acute improvements in Pao(2)/Fio(2) ratio (83.7%) and oxygenation index (46.7%). Study groups were of similar ages, gender, primary diagnoses, pediatric risk of mortality score, and mean airway pressure. Pao(2)/Fio(2) ratio was lower (CTG...

Endothelial and neuronal nitric oxide synthase inhibitors influences angiotensin II pressor effect in central nervous system

Saad, Wilson Abrão; Guarda, Ismael Francisco Motta Siqueira; Camargo, Luiz Antonio de Arreda; Saad, William Abrão; Guarda, Renata Saad; Santos, A. F. B. Talmir; Simões, Sylvio
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 341-347
Português
Relevância na Pesquisa
66.57%
The present study investigated the central role of angiotensin II and nitric oxide on arterial blood pressure (MAP) in rats. Losartan and PD123349 AT 1 and AT 2 (selective no peptides antagonists angiotensin receptors), as well as FK 409 (a nitric oxide donor), N W-nitro-L-arginine methyl ester (L-NAME) a constituve nitric oxide synthase inhibitor endothelial (eNOSI) and 7-nitroindazol (7NI) a specific neuronal nitric oxide synthase inhibitor (nNOSI) were used. Holtzman strain, (Rattus norvergicus) weighting 200-250 g were anesthetized with zoletil 50 mg kg -1 (tiletamine chloridrate 125 mg and zolazepan chloridrate 125 mg) into quadriceps muscle anda stainless steel cannula was stereotaxically implanted into their Lateral Ventricle (LV). Controls were injected with a 0.5 μl volume of 0.15 M NaCl. Angiotensin II injected into LV increased MAP (19±3 vs. control 3±1 mm Hg), which is potentiated by prior injection of L-NAME in the same site 26±2 mm Hg. 7NI injected prior to ANG II into LV also potentiated the pressor effect of ANG II but with a higher intensity than L-NAME 32±3 mm Hg. FK 409 inhibited the pressor effect of ANG II (6±1 mm Hg). Losartan injected into LV before ANG II influences the pressor effect of ANG II (8±1 mm Hg). The PD 123319 decreased the pressor effects of ANG II (16±1 mm Hg). Losartan injected simultaneously with FK 409 blocked the pressor effect of ANG II (3±1 mm Hg). L-NAME produced an increase in the pressor effect of ANG II...

Inhibition of in vivo leishmanicidal mechanisms by tempol: Nitric oxide down-regulation and oxidant scavenging

LINARES, Edlaine; GIORGIO, Selma; AUGUSTO, Ohara
Fonte: ELSEVIER SCIENCE INC Publicador: ELSEVIER SCIENCE INC
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
66.56%
Tempol (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy) has long been known to protect experimental animals from the injury associated with oxidative and inflammatory conditions. In the latter case, a parallel decrease in tissue protein nitration levels has been observed. Protein nitration represents a shift in nitric oxide actions from physiological to pathophysiological and potentially damaging pathways involving its derived oxidants such as nitrogen dioxide and peroxynitrite. In infectious diseases, protein tyrosine nitration of tissues and cells has been taken as evidence for the involvement of nitric oxide-derived oxidants in microbicidal mechanisms. To examine whether tempol inhibits the microbicidal action of macrophages, we investigated its effects on Leishmania amazonensis infection in vitro (RAW 264.7 murine macrophages) and in vivo (C57B1/6 mice). Tempol was administered in the drinking water at 2 mM throughout the experiments and shown to reach infected footpads as the nitroxide plus the hydroxylamine derivative by EPR analysis. At the time of maximum infection (6 weeks), tempol increased footpad lesion size (120%) and parasite burden (150%). In lesion extracts, tempol decreased overall nitric oxide products and expression of inducible nitric oxide synthase to about 80% of the levels in control animals. Nitric oxide-derived products produced by radical mechanisms...

The myth of nitric oxide in central cardiovascular control by the nucleus tractus solitarii

Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/1997 Português
Relevância na Pesquisa
66.57%
Considerable evidence suggests that nitroxidergic mechanisms in the nucleus tractus solitarii (NTS) participate in cardiovascular reflex control. Much of that evidence, being based on responses to nitric oxide precursors or inhibitors of nitric oxide synthesis, has been indirect and circumstantial. We sought to directly determine cardiovascular responses to nitric oxide donors microinjected into the NTS and to determine if traditional receptor mechanisms might account for responses to certain of these donors in the central nervous system. Anesthetized adult Sprague Dawley rats that were instrumented for recording arterial pressure and heart rate were used in the physiological studies. Microinjection of nitric oxide itself into the NTS did not produce any cardiovascular responses and injection of sodium nitroprusside elicited minimal depressor responses. The S-nitrosothiols, S-nitrosoglutathione (GSNO), S-nitrosoacetylpenicillamine (SNAP), and S-nitroso-D-cysteine (D-SNC) produced no significant cardiovascular responses while injection of S-nitroso-L-cysteine (L-SNC) elicited brisk, dose-dependent depressor and bradycardic responses. In contrast, injection of glyceryl trinitrate elicited minimal pressor responses without associated changes in heart rate. It is unlikely that the responses to L-SNC were dependent on release of nitric oxide in that 1) the responses were not affected by injection of oxyhemoglobin or an inhibitor of nitric oxide synthesis prior to injection of L-SNC and 2) L- and D-SNC released identical amounts of nitric oxide when exposed to brain tissue homogenates. Although GSNO did not independently affect blood pressure...

Cellular signaling with nitric oxide and cyclic GMP

Murad,F.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/1999 Português
Relevância na Pesquisa
66.56%
During the past two decades, nitric oxide signaling has been one of the most rapidly growing areas in biology. This simple free radical gas can regulate an ever growing list of biological processes. In most instances nitric oxide mediates its biological effects by activating guanylyl cyclase and increasing cyclic GMP synthesis. However, the identification of effects of nitric oxide that are independent of cyclic GMP is also growing at a rapid rate. The effects of nitric oxide can mediate important physiological regulatory events in cell regulation, cell-cell communication and signaling. Nitric oxide can function as an intracellular messenger, neurotransmitter and hormone. However, as with any messenger molecule, there can be too much or too little of the substance and pathological events ensue. Methods to regulate either nitric oxide formation, metabolism or function have been used therapeutically for more than a century as with nitroglycerin therapy. Current and future research should permit the development of an expanded therapeutic armamentarium for the physician to manage effectively a number of important disorders. These expectations have undoubtedly fueled the vast research interests in this simple molecule.

Piper sarmentosum increases nitric oxide production in oxidative stress: a study on human umbilical vein endothelial cells

Ugusman,Azizah; Zakaria,Zaiton; Hui,Chua Kien; Nordin,Nor Anita Megat Mohd
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 Português
Relevância na Pesquisa
66.56%
OBJECTIVE: Nitric oxide produced by endothelial nitric oxide synthase (eNOS) possesses multiple anti-atherosclerotic properties. Hence, enhanced expression of eNOS and increased Nitric oxide levels may protect against the development of atherosclerosis. Piper sarmentosum is a tropical plant with antioxidant and anti-inflammatory activities. This study aimed to investigate the effects of Piper sarmentosum on the eNOS and Nitric oxide pathway in cultured human umbilical vein endothelial cells (HUVECs). METHODS: HUVECs were divided into four groups: control, treatment with 180 μM hydrogen peroxide (H2O2), treatment with 150 μg/mL aqueous extract of Piper sarmentosum, and concomitant treatment with aqueous extract of PS and H2O2 for 24 hours. Subsequently, HUVECs were harvested and eNOS mRNA expression was determined using qPCR. The eNOS protein level was measured using ELISA, and the eNOS activity and Nitric oxide level were determined by the Griess reaction. RESULTS: Human umbilical vein endothelial cells treated with aqueous extract of Piper sarmentosum showed a marked induction of Nitric oxide. Treatment with PS also resulted in increased eNOS mRNA expression, eNOS protein level and eNOS activity in HUVECs. CONCLUSION: Aqueous extract of Piper sarmentosum may improve endothelial function by promoting NO production in HUVECs.

Is there a relationship between endothelial nitric oxide synthase gene polymorphisms and ankylosing spondylitis?

Sari,Ismail; Igci,Yusuf Ziya; Can,Gercek; Taylan,Ali; Solmaz,Dilek; Gogebakan,Bulent; Akar,Servet; Eslik,Zeynep; Bozkaya,Giray; Akkoc,Nurullah
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2013 Português
Relevância na Pesquisa
66.59%
OBJECTIVE: Nitric oxide is produced by endothelial nitric oxide synthase, and its production can be influenced by polymorphisms of the endothelial nitric oxide synthase gene. Because candidate genes responsible for susceptibility to ankylosing spondylitis are mostly unknown and available data suggest that there may be problems related to the nitric oxide pathway, such as endothelial dysfunction and increased asymmetric dimethylarginine, this study aimed to assess the association of common endothelial nitric oxide synthase gene polymorphisms with ankylosing spondylitis. METHODS: One hundred ninety-four unrelated Turkish ankylosing spondylitis patients and 113 healthy without apparent cardiovascular disease, hypertension or diabetes mellitus were included. All individuals were genotyped by PCR-RFLP for two single-nucleotide polymorphisms, namely 786T>C (rs2070744, promoter region) and 786 Glu298Asp (rs1799983, exon 7). Variable numbers of tandem repeat polymorphisms in intron 4 were also studied and investigated by direct electrophoresis on agarose gel following polymerase chain reaction analysis. The Bath ankylosing spondylitis metrology index of the patients was calculated, and human leukocyte antigen B27 was studied. RESULTS: All studied polymorphisms satisfied Hardy-Weinberg equilibrium. Sex distributions were similar between the patient and control groups. No significant differences were found in the distributions of allele and genotype frequencies of the studied endothelial nitric oxide synthase polymorphisms between patients and controls. There were no correlations between endothelial nitric oxide synthase polymorphisms...

Arginase activity and nitric oxide levels in patients with obstructive sleep apnea syndrome

Yüksel,Meral; Okur,Hacer Kuzu; Pelin,Zerrin; Ö?ünç,Ayliz Velio?lu; Öztürk,Levent
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 Português
Relevância na Pesquisa
66.6%
OBJECTIVE: Obstructive sleep apnea syndrome is characterized by repetitive obstruction of the upper airways, and it is a risk factor for cardiovascular diseases. There have been several studies demonstrating low levels of nitric oxide in patients with obstructive sleep apnea syndrome compared with healthy controls. In this study, we hypothesized that reduced nitric oxide levels would result in high arginase activity. Arginase reacts with L-arginine and produces urea and L-ornithine, whereas L-arginine is a substrate for nitric oxide synthase, which produces nitric oxide. METHODS: The study group consisted of 51 obstructive sleep apnea syndrome patients (M/F: 43/8; mean age 49±10 years of age) and 15 healthy control subjects (M/F: 13/3; mean age 46±14 years of age). Obstructive sleep apnea syndrome patients were divided into two subgroups based on the presence or absence of cardiovascular disease. Nitric oxide levels and arginase activity were measured via an enzyme-linked immunosorbent assay of serum samples. RESULTS: Serum nitric oxide levels in the control subjects were higher than in the obstructive sleep apnea patients with and without cardiovascular diseases (p<0.05). Arginase activity was significantly higher (p<0.01) in obstructive sleep apnea syndrome patients without cardiovascular diseases compared with the control group. Obstructive sleep apnea syndrome patients with cardiovascular diseases had higher arginase activity than the controls (p<0.001) and the obstructive sleep apnea syndrome patients without cardiovascular diseases (p<0.05). CONCLUSION: Low nitric oxide levels are associated with high arginase activity. The mechanism of nitric oxide depletion in sleep apnea patients suggests that increased arginase activity might reduce the substrate availability of nitric oxide synthase and thus could reduce nitric oxide levels.

Nitric Oxide Metabolism and Resistance to Peroxynitrite by Neisseria Species

Barth, Kenneth Raymond ; Clark, Virginia L.
Fonte: Universidade de Rochester Publicador: Universidade de Rochester
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
66.64%
Thesis (Ph.D.)--University of Rochester. School of Medicine and Dentistry. Dept. of Microbiology and Immunology, 2009.; Neisseria gonorrhoeae is the causative agent of gonorrhea, a sexually transmitted disease that primarily infects the urogenital tract. Prolonged infection often leads to complications, such as disseminated gonococcal infection and pelvic inflammatory disease. Women specifically have high rates of asymptomatic disease that we believe are partially an effect of bacterial metabolism of nitric oxide, considering nitric oxide levels directly correlate with immune system state of activation. The central role of nitric oxide within the immune system involves not only its signaling properties, but also its toxic properties. My studies have focused on examining the ability of Neisseria species to both produce and degrade nitric oxide, while establishing a nitric oxide steady-state in the presence of nitrite or an exogenous source of nitric oxide, as well as its resistance to the toxic nitrogen species, nitric oxide and peroxynitrite. Both pathogenic and commensal Neisseria species were found to have similar enzymatic activities for the production and degradation of nitric oxide, in addition to being equally efficient at modulating nitric oxide levels from pro-inflammatory concentrations to non-inflammatory concentrations during denitrification. Auxotrophic strains requiring arginine...

Nitric oxide effect on colonocyte metabolism: co-action of sulfides and peroxide

Roediger, W.; Babidge, W.
Fonte: Kluwer Academic Publ Publicador: Kluwer Academic Publ
Tipo: Artigo de Revista Científica
Publicado em //2000 Português
Relevância na Pesquisa
66.62%
Luminal levels of nitric oxide/nitrite are high in colitis. Whether nitric oxide is injurious or protective to human colonocytes is unknown and the role of nitric oxide in the genesis of colitis unclear. The aims were to establish whether nitric oxide was injurious to oxidation of substrates (n-butyrate and D-glucose) in isolated human and rat colonocytes both alone and in the presence of hydrogen sulfide and hydrogen peroxide, agents implicated in cell damage of colitis. Nitric oxide generation from S-nitrosoglutathione was measured by nitrite appearance. Colonocytes were isolated and incubated with [1-14C] butyrate or [6-14C] glucose and 2.6 microM nitric oxide, 1.5 mM sodium hydrogen sulfide or 2.5 mM hydrogen peroxide. Acyl-CoA esters were measured by high performance liquid chromatography, 14CO2 radiochemically and lactate/ketones by enzymic methods. Results indicate that nitric oxide very significantly (p < .001) reduced acyl-CoA formation but did not impair 14CO2 generation. Peroxide and sulfide with nitric oxide resulted in significant reduction (p < 0.01) of substrate oxidation to CO2. Sulfide significantly stimulated release of nitric oxide from S-nitrosoglutathione. The principal conclusion is that nitric oxide diminishes CoA metabolism in colonocytes. CoA depletion has been observed in chronic human colitis for which a biochemical explanation has been lacking. For acute injurious action in human colonocytes nitric oxide requires co-action of peroxide and sulfide to impair oxidation of substrates in cells. From current observations treatment of colitis should aim to reduce simultaneously nitric oxide...

Anticipation of Nitric Oxide Stress in the Human Commensal Fungus Candida albicans

Lynn, Jed
Fonte: Universidade Rice Publicador: Universidade Rice
Português
Relevância na Pesquisa
66.61%
Candida albicans is the most common human commensal fungus, able to colonize host niches such as skin, mouth and gastrointestinal tract. Colonization of diverse microenvironments requires the ability to evade or overcome innate host protection and adapt to rapid transitions between environments with different stresses and nutrient availability. Colonization of the gastrointestinal tract requires passage through the stomach containing toxic levels of nitric oxide, generated from acidification of nitrite in the low pH of the stomach. Although resistance of C. albicans to nitric oxide is mediated by the flavohemoglobin Yhb1, little is known about the physiologically relevant ligands that regulate YHB1 expression. Here I propose the hypothesis that nontoxic saliva chemicals induce YHB1 expression and promote resistance to nitric oxide generated in the stomach. Supporting this hypothesis is the observation that two ions actively concentrated in the saliva – nitrate and thiocyanate – induce YHB1 expression. Indeed, whole-genome transcriptional analysis of C. albicans treated with nitrate or thiocyanate produce gene expression profiles nearly identical to cells treated with nitrite or nitric oxide. Pretreatment of C. albicans with either of these two nontoxic compounds increases resistance of the yeast to nitric oxide. I propose that this is an evolved response in which C. albicans anticipates nitric oxide stress generated in the stomach. C. albicans thus upregulates nitric oxide stress response genes in response to saliva signals that precede nitric oxide formation further on in the gut. Only a few examples of anticipatory signaling have so far been identified and it is not known how common this type of regulation is among microbes. Expression of the YHB1 gene in response to nitric oxide is regulated by the transcription factor Cta4. I show that Cta4 binds to the YHB1 promoter in vivo as a homodimer and is necessary...

Nitric oxide regulates neurogenesis in adult olfactory epithelium in vitro

Bellette, Bernadette; Iturriaga, Rodrigo; Bacigalupo Vicuña, Juan Domingo; Mackay-Sim, Alan; Astorga, Guadalupe; Sülz, Lorena
Fonte: ACADEMIC PRESS INC ELSEVIER SCIENCE Publicador: ACADEMIC PRESS INC ELSEVIER SCIENCE
Tipo: Artículo de revista
Português
Relevância na Pesquisa
66.56%
Nitric oxide regulates neurogenesis in the developing and adult brain. The olfactory epithelium is a site of neurogenesis in the adult and previous studies suggest a role for nitric oxide in this tissue during development. We investigated whether neuronal precursor proliferation and differentiation is regulated by nitric oxide using primary cultures of olfactory epithelial cells and an immortalized, clonal, neuronal precursor cell line derived from adult olfactory epithelium. In these cultures NOS inhibition reduced cell proliferation and stimulated neuronal differentiation, including expression of a voltage-dependent potassium conductance of the delayed rectifier type. In the neuronal precursor cell line, differentiation was associated with a significant decrease in nitric oxide release. In contrast, addition of nitric oxide stimulated proliferation and reduced neuronal differentiation. Nitric oxide regulated olfactory neurogenesis independently of added growth factors. Taken together these results indicate that nitric oxide levels can regulate cell proliferation and neuronal differentiation of olfactory precursor cells.; This work was supported in part by a Sir Allan Sewell Fellowship from Griffith University to J.B., grants from MIDEPLAN ICM P99-031-F and ICM P05-001-F...

Piper sarmentosum increases nitric oxide production in oxidative stress: a study on human umbilical vein endothelial cells

Ugusman, Azizah; Zakaria, Zaiton; Hui, Chua Kien; Nordin, Nor Anita Megat Mohd
Fonte: Universidade de São Paulo. Faculdade de Medicina Publicador: Universidade de São Paulo. Faculdade de Medicina
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/01/2010 Português
Relevância na Pesquisa
66.56%
OBJECTIVE: Nitric oxide produced by endothelial nitric oxide synthase (eNOS) possesses multiple anti-atherosclerotic properties. Hence, enhanced expression of eNOS and increased Nitric oxide levels may protect against the development of atherosclerosis. Piper sarmentosum is a tropical plant with antioxidant and anti-inflammatory activities. This study aimed to investigate the effects of Piper sarmentosum on the eNOS and Nitric oxide pathway in cultured human umbilical vein endothelial cells (HUVECs). METHODS: HUVECs were divided into four groups: control, treatment with 180 μM hydrogen peroxide (H2O2), treatment with 150 μg/mL aqueous extract of Piper sarmentosum, and concomitant treatment with aqueous extract of PS and H2O2 for 24 hours. Subsequently, HUVECs were harvested and eNOS mRNA expression was determined using qPCR. The eNOS protein level was measured using ELISA, and the eNOS activity and Nitric oxide level were determined by the Griess reaction. RESULTS: Human umbilical vein endothelial cells treated with aqueous extract of Piper sarmentosum showed a marked induction of Nitric oxide. Treatment with PS also resulted in increased eNOS mRNA expression, eNOS protein level and eNOS activity in HUVECs. CONCLUSION: Aqueous extract of Piper sarmentosum may improve endothelial function by promoting NO production in HUVECs.

Arginase activity and nitric oxide levels in patients with obstructive sleep apnea syndrome

Yuksel, Meral; Okur, Hacer Kuzu; Pelin, Zerrin; Ogunç, Ayliz Velioglu; Oztuk, Levent
Fonte: Universidade de São Paulo. Faculdade de Medicina Publicador: Universidade de São Paulo. Faculdade de Medicina
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; Formato: application/pdf
Publicado em 01/04/2014 Português
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66.6%
OBJECTIVE: Obstructive sleep apnea syndrome is characterized by repetitive obstruction of the upper airways, and it is a risk factor for cardiovascular diseases. There have been several studies demonstrating lowlevels of nitric oxide in patients with obstructive sleep apnea syndrome compared with healthy controls. In this study, we hypothesized that reduced nitric oxide levels would result in high arginase activity. Arginase reacts with L-arginine and produces urea and L-ornithine, whereas L-arginine is a substrate for nitric oxide synthase, which produces nitric oxide. METHODS: The study group consisted of 51 obstructive sleep apnea syndrome patients (M/F: 43/8; mean age 49¡10 years of age) and 15 healthy control subjects (M/F: 13/3; mean age 46¡14 years of age). Obstructive sleep apnea syndrome patients were divided into two subgroups based on the presence or absence of cardiovascular disease. Nitric oxide levels and arginase activity were measured via an enzyme-linked immunosorbent assay of serum samples.RESULTS: Serum nitric oxide levels in the control subjects were higher than in the obstructive sleep apnea patients with and without cardiovascular diseases (p,0.05). Arginase activity was significantly higher (p,0.01) in obstructive sleep apnea syndrome patients without cardiovascular diseases compared with the control group. Obstructive sleep apnea syndrome patients with cardiovascular diseases had higher arginase activity than the controls (p...

Is there a relationship between endothelial nitric oxide synthase gene polymorphisms and ankylosing spondylitis?

Sari, Ismail; Igci, Yusuf Ziya; Can, Gercek; Taylan, Ali; Solmaz, Dilek; Gogebakan, Bulent; Akar, Servet; Eslik, Zeynep; Bozkaya, Giray; Akkoc, Nurullah
Fonte: Universidade de São Paulo. Faculdade de Medicina Publicador: Universidade de São Paulo. Faculdade de Medicina
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; Formato: application/pdf
Publicado em 01/01/2013 Português
Relevância na Pesquisa
66.59%
OBJECTIVE: Nitric oxide is produced by endothelial nitric oxide synthase, and its production can be influenced by polymorphisms of the endothelial nitric oxide synthase gene. Because candidate genes responsible for susceptibility to ankylosing spondylitis are mostly unknown and available data suggest that there may be problems related to the nitric oxide pathway, such as endothelial dysfunction and increased asymmetric dimethylarginine, this study aimed to assess the association of common endothelial nitric oxide synthase gene polymorphisms with ankylosing spondylitis. METHODS: One hundred ninety-four unrelated Turkish ankylosing spondylitis patients and 113 healthy without apparent cardiovascular disease, hypertension or diabetes mellitus were included. All individuals were genotyped by PCR-RFLP for two single-nucleotide polymorphisms, namely 786T>;C (rs2070744, promoter region) and 786 Glu298Asp (rs1799983, exon 7). Variable numbers of tandem repeat polymorphisms in intron 4 were also studied and investigated by direct electrophoresis on agarose gel following polymerase chain reaction analysis. The Bath ankylosing spondylitis metrology index of the patients was calculated, and human leukocyte antigen B27 was studied. RESULTS: All studied polymorphisms satisfied Hardy-Weinberg equilibrium. Sex distributions were similar between the patient and control groups. No significant differences were found in the distributions of allele and genotype frequencies of the studied endothelial nitric oxide synthase polymorphisms between patients and controls. There were no correlations between endothelial nitric oxide synthase polymorphisms...