Search results for "nitric Oxide"

Endothelial dysfunction in morbid obesity.

2013

Morbid obesity is a chronic multifunctional disease characterized by an accumulation of fat. Epidemiological studies have shown that obesity is associated with cardiovascular and metabolic disorders. Endothelial dysfunction, as defined by an imbalance between relaxing and contractile endothelial factors, plays a central role in the pathogenesis of these cardiometabolic diseases. Diminished bioavailability of nitric oxide (NO) contributes to endothelial dysfunction and impairs endothelium- dependent vasodilatation. But this is not the only mechanism that drives to endothelial dysfunction. Obesity has been associated with a chronic inflammatory process, atherosclerosis, and oxidative stress. …

Endothelial nitric oxide synthase in vascular disease: from marvel to menace.

2006

Nitric oxide (NO·) is an important protective molecule in the vasculature, and endothelial NO· synthase (eNOS) is responsible for most of the vascular NO· produced. A functional eNOS oxidizes its substrate l -arginine to l -citrulline and NO·. This normal function of eNOS requires dimerization of the enzyme, the presence of the substrate l -arginine, and the essential cofactor (6 R )-5,6,7,8-tetrahydro- l -biopterin (BH 4 ), one of the most potent naturally occurring reducing agents. Cardiovascular risk factors such as hypertension, hypercholesterolemia, diabetes mellitus, or chronic smoking stimulate the production of reactive oxygen species in the vascular wall. Nicotinamide adenine dinu…

Vascular aging in women: is estrogen the fountain of youth?

2012

Aging is a physiological process associated with structural and functional changes in vasculature, including endothelial dysfunction, arterial stiffening and remodeling, impaired angiogenesis, and defective vascular repair, and with an increasing prevalence of atherosclerosis. The risk of cardiovascular disease differs between men and women, remaining lower in women during their fertile years and reaching values similar to their male peers after menopause. Menopause is marked by the loss of endogenous estrogen production. Therefore, estrogens have been implicated in premenopausal protection from cardiovascular disease, an assumption supported by experimental and some clinical studies, where…

Expression of different isoforms of nitric oxide synthase in experimentally denervated and reinnervated skeletal muscle.

1997

Denervated muscle fibers express enhanced levels of stress and apoptosis-associated proteins and undergo apoptosis. In experimentally denervated and reinnervated rat facial muscle, we now evaluate changes in the expression patterns of different isoforms of nitric oxide synthase (NOS)-generating nitric oxide (NO), which mediates oxidative stress and apoptosis. Physiological expression of NOS corresponds to a constant sarcolemmal staining pattern for neuronal NOS (nNOS) and a patchy sarcolemmal and weak sarcoplasmic labeling for the endothelial NOS-isoform, with no expression for inducible NOS (iNOS). Denervated muscle displayed distinct downregulation of nNOS with preserved expression of dys…

Sirolimus-Induced Vascular Dysfunction

2008

Objectives This study sought to analyze mechanisms that mediate vascular dysfunction induced by sirolimus. Background Despite excellent antirestenotic capacity, sirolimus-eluting stents have been found to trigger coronary endothelial dysfunction and impaired re-endothelialization. Methods To mimic the continuous sirolimus exposure of a stented vessel, Wistar rats underwent drug infusion with an osmotic pump for 7 days. Results Sirolimus treatment caused a marked degree of endothelial dysfunction as well as a desensitization of the vasculature to the endothelium-independent vasodilator nitroglycerin. Also, sirolimus stimulated intense transmural superoxide formation as detected by dihydroeth…

Correlation between a marker of oxidative stress and few indexes of endothelial dysfunction in essential hypertensive patients

2005

Cost-effectiveness of switching from omalizumab to mepolizumab in uncontrolled severe eosinophilic asthma

2020

Background: Severe asthma is burdened by frequent exacerbations and use of oral corticosteroids (OCS) which worsen patients’ quality of life and increased healthcare spending. Objectives: To assess the clinical and economic impact of switching from omalizumab (OMA) to mepolizumab (MEP) in patients eligible for both biologics but not optimally controlled with OMA. Methods: Uncontrolled patients referred to 6 asthma clinics in south of Italy switched from OMA to MEP, were enrolled and followed-up to Jan 2020. Clinical information included blood eosinophil count, asthma control test (ACT), pulmonary function, IgE, exhaled nitric oxide (FeNO), OCS intake, drugs, exacerbations/hospitalizations, …

Adrenergic Stimulation of Cyclic GMP Formation Requires NO-Dependent Activation of Cytosolic Guanylate Cyclase in Rat Pinealocytes

1993

Cyclic GMP (cGMP) formation in rat pinealocytes is regulated through a synergistic dual receptor mechanism involving beta- and alpha 1-adrenergic receptors. The effects of NG-monomethyl-L-arginine (NMMA), which inhibits nitric oxide (NO) synthase and NO-mediated activation of cytosolic guanylate cyclase, and methylene blue (MB), which inhibits cytosolic guanylate cyclase, were investigated in an attempt to understand the role of NO in adrenergic cGMP formation. Both NMMA and MB inhibited beta-adrenergic stimulation of cGMP formation as well as alpha 1-adrenergic potentiation of beta-adrenergic stimulation of cGMP formation, whereas they had no effect in unstimulated pinealocytes. The inhibi…

Characterization of nitric oxide synthase isoforms expressed in different structures of the guinea pig cochlea.

1997

Nitric oxide synthase (NOS) activity and NADPH diaphorase staining has previously been reported in mammalian cochlea. Here we demonstrate immunoreactivity for neuronal-type NOS I and endothelial-type NOS III in the cochlea of the guinea pig. NOS I immunoreactivity was seen in inner and outer hair cells, and spiral ganglion cells. Staining for NOS I was also shown in basal and intermediate cells of the stria vascularis, spiral ligament cells, and the media of vessels near the modiolus. An antibody to NOS III stained primarily vascular endothelial cells. Some NOS III immunoreactivity was also detected in spiral ganglion cells. An antibody to the inducible-type NOS II did not stain any structu…

Increase by NO synthase inhibitors of acetylcholine release from guinea-pig myenteric plexus

1994

The effects of nitric oxide (NO) synthase inhibitors on the electrically evoked release of [3H]acetylcholine were studied in guinea-pig myenteric plexus preparations preincubated with [3H]choline. NG-monomethyl-L-arginine (EC50 5.3 mumol l-1) and NG-nitro-L-arginine (EC50 1.3 mumol l-1) concentration-dependently increased the evoked release of [3H]acetylcholine without affecting the basal outflow. The facilitatory effect of NG-mono-methyl-L-arginine was prevented by L-arginine but not by D-arginine. The results suggest that endogenous NO inhibits the depolarisation-evoked release of acetylcholine.