Search Results
Results 501 - 550 of 1219
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Gorenflo M - - 2001
Asymmetrical dimethyl-L-arginine (ADMA) is an endogenous inhibitor of nitric oxide synthase. We hypothesized that plasma levels of ADMA could be increased in patients with congenital heart disease and pulmonary hypertension. Cardiac catheterization was performed in 20 children and young adults with congenital heart disease with a median age of 10 ...
Doursout M F - - 2001
The aim of this study was to elucidate cardiac and regional hemodynamics using a nonspecific inhibitor of the constitutive and inducible nitric oxide synthase (NOS), N-methyl-L-arginine (L-NMA), and a specific inhibitor of the inducible NOS, aminoguanidine, in conscious pigs. Animals were divided into two groups. After hemodynamics were stabilized, animals ...
McVeigh G E - - 2001
Traditionally, nitric oxide-mediated alteration in blood vessel tone has been inferred from changes in flow in response to physical and pharmacological interventions using plethysmographic or ultrasonic techniques. We hypothesized that alteration in pulsatile arterial function may represent a more sensitive measure to detect and monitor nitric oxide-mediated modulation of arterial ...
Doherty P C - - 2001
PURPOSE: Zaprinast, dipyridamole and sildenafil were injected into the corpora cavernosa of cats to determine whether changes in the steady state level of cyclic guanosine monophosphate (cGMP) induced by inhibiting type 5 phosphodiesterase would cause an erectile response. MATERIALS AND METHODS: Increases in intracavernous pressure, penile length and erectile response ...
Pinelli A - - 2001
Nitric oxide plays a key role as a vasodilating agent and its deficiency is associated with ischemic heart diseases. The aim of this study was to induce biochemical alterations associated with ischemic heart lesions by blocking nitric oxide synthase. L-NAME, a nitric oxide synthase inhibitor, was administered to rabbits and ...
Lassila M - - 2001
Functional and morphological changes of blood vessels in cyclosporine A (CsA)-induced hypertension and nephrotoxicity were studied in spontaneously hypertensive rats (SHR). The role of the L-arginine-nitric oxide (NO) pathway and the importance of oxidative stress in CsA toxicity were also assessed. SHR (7-8 week old) on a high-sodium diet were ...
Sullivan J C - - 2001
The objective of this study was to examine the effects of gender and age on electrical field stimulation (EFS)-induced vasoconstriction. Fisher 344 rats were studied: young females (YF, n = 38), young males (YM, n = 29), old females (OF, n = 33), and old males (OM, n = 30). ...
Ryan K L - - 2001
The purpose of this study was to determine whether nitric oxide (NO) contributes to the hypotensive state induced by prolonged environmental heat (EH) stress. Ketamine-anesthetized rats were instrumented for the measurement of arterial blood pressure, electrocardiogram, and temperature at four sites. Rats were exposed to EH (ambient temperature, 40 +/- ...
Bravo G - - 2001
The early cardiovascular effects resulting from an acute spinal cord injury (SCI) produced by a contusion procedure at T5-T6 were evaluated in anaesthetized rats. The mean arterial pressure (MAP) and heart rate (HR) were measured during one hour after the injury. A marked decrease in MAP and HR was observed ...
Schröder M - - 2001
Hypertension contributes to cardiac and cerebrovascular complications in HD patients. Endogenous inhibitors of nitric oxide synthase accumulate in renal failure and may interfere with the regulation of vascular tone. We investigated the elimination of asymmetric dimethylarginine (ADMA) by using biocompatible Polyamide Strade mark membranes in low-flux (Polyflux 6L) or high-flux ...
Vassalli F - - 2001
OBJECTIVE: We tested the hypothesis that carbon monoxide might participate in the modulation of hypoxic pulmonary vasoconstriction (HPV) by prostacyclin (PGI2) and nitric oxide. DESIGN: Prospective, interventional study. SETTING: University laboratory. SUBJECTS: Nineteen intact anesthetized mongrel dogs. INTERVENTIONS: Right heart catheterization for the measurements of mean pulmonary artery pressure (Ppa), ...
Golding E M - - 2001
In the middle cerebral artery (MCA), the presence of nitric oxide (NO) is responsible for maintaining a more dilated state than in its absence during increases in extracellular K(+) and osmolality. The purpose of the present study was to determine whether the involvement of NO was due to (a) a ...
Liu G Z - - 2001
STUDY DESIGN: This in vitro study clarifies the role of nitric oxide (NO) in human lumbar intervertebral disc metabolism. OBJECTIVE: To investigate the effects of NO on proteoglycan synthesis in human lumbar discs and to test the hypothesis that NO is a mediator of the changes in proteoglycan synthesis in ...
Tworetzky W - - 2001
To investigate the oxygenation and haemodynamic dose response to inhaled nitric oxide in neonates with persistent pulmonary hypertension (PPHN), we gave seven neonates nitric oxide and measured directly pulmonary arterial pressure. Inhaled nitric oxide produced peak improvement in oxygenation at 5 parts per million (ppm) whereas peak improvement in the ...
Klahr S - - 2001
Endothelial nitric oxide synthase (eNOS) serves a number of functions in the vasculature. In response to stimuli such as shear stress or acetylcholine, eNOS catalyses the production of nitric oxide (NO) from L-arginine. The NO diffuses across the endothelium into neighbouring smooth muscle and induces vasodilation. NO also acts locally ...
Manjari V - - 2001
Vegetarians are known to have a low incidence of cardiovascular diseases and lower blood pressure compared to non-vegetarians. The exact cause for this is not known. In the present study, it was found that, in general, vegetarians (female > males) have a higher concentrations of anti-oxidant enzymes: catalase and superoxide ...
Li L - - 2001
The hypertensive rat model was made by chronic stress of electric foot-shocks and noises. On such hypertensive rats, when anesthetized with urethane and chloralose, the electroacupuncture (EA) to bilateral "Zusanli (st.36)" acupoints for 20 min, could result in a depressor (including both systolic and diastolic pressure) and bradycardiac response as ...
Cases A - - 2001
This study evaluated the effects of progressive nitric oxide (NO) inhibition in the regulation of systemic and regional hemodynamics and renal function in anesthetized dogs. The N(G)-nitro-L-arginine methyl ester group (n = 9) received progressive doses of 0.1, 1, 10, and 50 microg. kg(-1). min(-1). Renal (RBF), mesenteric (MBF), iliac ...
Abraham P - - 2001
We recently demonstrated that a pressure-induced vasodilation results from local nonnociceptive stimulation of the skin of the human hand. We aimed to test the hypothesis that this vasodilation was not a short-lived response to a single type of pressure strain, but could be a widely activated and prolonged protective cutaneous ...
Kita I - - 2000
Yawing was induced by microinjections of L-glutamate, cyanide and a nitric oxide-releasing compound (NOC12) into the paraventricular nucleus of the hypothalamus (PVN) in anesthetized, spontaneously breathing rats. To evaluate physiological aspects of yawning, we monitored intercostal electromyogram (EMG) as an index of inspiratory activity, digastric EMG, blood pressure and electrocorticogram ...
Krasuski R A - - 2000
OBJECTIVES: We sought to compare the responses of patients with pulmonary hypertension from primary and secondary causes (PPH and SPH, respectively) to inhaled nitric oxide (iNO) in the cardiac catheterization laboratory. BACKGROUND: Pulmonary hypertension can lead to right ventricular pressure overload and failure. Although vasodilators are effective as therapy in ...
Kiel J W - - 2000
Based on the previous finding that locally produced nitric oxide (NO) and endothelin (ET) exert competing effects on choroidal resistance vessels, the present study sought to further characterize the pharmacology of ET in the choroid. The specific goal was to quantify the choroidal blood flow responses to acute changes in ...
Paniagua O A - - 2000
Hypertension is associated with decreased endothelium-dependent vasodilation. However, whether endothelial dysfunction is a cause or a consequence of elevated blood pressure is unknown. Therefore, to determine whether hypertension can directly induce endothelial dysfunction, we investigated the effect of increases in intra-arterial pressure on endothelium-dependent vasodilation of the human microvasculature. Small ...
Fulep E E - - 2000
The responses to endothelial vasodilators and exogenous nitric oxide (NO) were characterized in intact isolated uterine vascular beds of nonpregnant, midpregnant and late-pregnant rats perfused with Kreb's buffer (37 degrees C, 5% CO(2) in air, pH approximately 7.4) containing 2% dextran and indomethacin. Phenylephrine increased perfusion pressure in the vascular ...
Kato M - - 2000
BACKGROUND: Patients with obstructive sleep apnea (OSA) experience repetitive episodic hypoxemia with consequent sympathetic activation and marked blood pressure surges, each of which may impair endothelial function. We tested the hypothesis that patients with OSA have impaired endothelium-dependent vasodilation, even in the absence of overt cardiovascular disease. METHODS AND RESULTS: ...
Guerrero F - - 2000
We examined in vitro vascular reactivity of eels previously acclimatized to 10.1 MPa hydrostatic pressure (HP) for 21 days. The isometric tension developed by ventral aortic rings was measured at atmospheric pressure. Dose-response curves for either acetylcholine (ACh) or noradrenaline (NA), as well as contractions evoked by 80 mM K+, ...
Wen C - - 2000
1. L-arginine prevents adrenocorticotrophin (ACTH)-induced hypertension in the rat. To confirm that this effect is mediated through the nitric oxide (NO) system, we examined whether N-nitro-L-arginine (NOLA) could reverse the L-arginine-induced blockade of ACTH-induced hypertension. 2. Blood pressure and metabolic parameters were examined in sham-, ACTH-, L-arginine + sham-, NOLA ...
Sentürk U K - - 2000
The aim of this study was to determine the levels of tissue and blood zinc (Zn), copper (Cu), magnesium (Mg) in nitric oxide (NO) synthase blockade-induced hypertension. A group of albino rats received a NO synthase inhibitor, N(G)-nitro-L-arginine-methyl ester (L-NAME, 60 mg/kg/d) in their drinking water for 21 d. L-NAME ...
Golding E M - - 2000
After traumatic brain injury, extracellular K(+) in brain can dramatically increase. We studied the effects of increased K(+) on the isolated pressurized rat middle cerebral artery (MCA). MCAs (200-250 microm OD) were isolated, cannulated with glass micropipettes, and pressurized. K(+) was increased in the extraluminal bath using three paradigms: (1) ...
Stauss Harald M. - - 2000
Blood pressure instability may promote cardiovascular morbidity. Recent data suggest a role of nitric oxide in stabilizing arterial blood pressure. A rise in blood pressure enhances endothelial shear stress and nitric oxide release. The resulting vasodilation antagonizes the initial increase in blood pressure. This system can respond within 2-10 seconds.
Yamaguchi K - - 2000
OBJECTIVE: To examine local actions of nitric oxide (NO) on the neural mechanisms controlling the release of vasopressin (AVP) and the cardiovascular system in the anteroventral third ventricular region (AV3V), a pivotal area for autonomic functions, and to pursue the problem of whether it may have any role in the ...
Doi H - - 2000
OBJECTIVE: To demonstrate tissue selective brady-kinin (BK) potentiating action of angiotensin converting enzyme inhibitors, we studied effects of imidaprilat and ramiprilat, active metabolites of imidapril and ramipril, respectively, on bronchoconstriction and hypotension both induced by BK in vasopressin-infused anesthetized guinea pigs. METHODS: We measured pulmonary inflation pressure and blood pressure ...
Spieker L E - - 2000
The vascular endothelium synthesizes and releases a spectrum of vasoactive substances like nitric oxide (NO) and endothelin (ET). In hypertension, the delicate balance of endothelium-derived factors is disturbed. ET acts as the natural counterpart to endothelium-derived NO, which exerts vasodilating, antithrombotic, and antiproliferative effects, and inhibits leukocyte-adhesion to the vascular ...
Morimoto S - - 2000
Nitric oxide is a messenger molecule having various functions in the brain. Previous studies have reported conflicting results for the roles of nitric oxide in the rostral ventrolateral medulla, a major center that regulates sympathetic and cardiovascular activities. We hypothesized that in this region, nitric oxide may have a biphasic ...
Gan L M - - 2000
OBJECTIVE: By using a computerized vascular perfusion model, we investigated temporal effects of sub-acute pressure elevation on vasomotor behavior and expression of endothelin-1 (ET-1) and endothelial nitric oxide synthase (eNOS) in intact human conduit vessels. METHODS: Paired umbilical veins were perfused during 1.5, 3 and 6 h under high/low intraluminal ...
Rais-Bahrami K - - 2000
OBJECTIVE: To test the hypothesis that inhaled nitric oxide, when combined with high-frequency oscillatory ventilation, is an effective therapeutic agent in meconium aspiration syndrome. DESIGN: Prospective, interventional study. SETTING: The animal research laboratory at The Children's National Medical Center. SUBJECTS: Five newborn piglets, 1-2 wks old, weighing 3.6 +/- 0.2 ...
Joa J C - - 2000
Effects of sodium nitroprusside (SNP), a nitric oxide donor, on the action potential in isolated guinea-pig sinoatrial nodes and ventricular papillary muscles were investigated. In the driven ventricular papillary muscle, SNP (10(-10)-10(-3) M) decreased the twitch tension in a concentration-dependent manner without significantly changing the configuration of action potential and ...
Mori T A - - 2000
BACKGROUND: Recent evidence supports differential effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the 2 major omega3 fatty acids of marine origin, on blood pressure in humans and vascular reactivity in adult spontaneously hypertensive rats. We investigated possible differences in the effects of purified EPA or DHA on forearm ...
Balasubramanyan N - - 2000
Although significant pulmonary hypertension can occur in patients treated with either hypocapnic alkalosis or "permissive" hypercapnic acidosis, the effects of sustained alkalosis or acidosis on subsequent vasodilator responses have not been established. This study measured the effects of 60-100 min of sustained alkalosis or acidosis on endothelium-independent and -dependent vasodilation ...
Textor S C - - 2000
Calcineurin inhibitors are a mainstay of transplant immunosuppression and commonly induce hypertension. They are highly lipid soluble and penetrate vascular smooth muscle cell membranes readily. Changes in vascular tone are universally observed during administration of these agents, particularly within the kidney, leading to diminished glomerular filtration and enhanced sodium retention. ...
Okatani Y - - 2000
We evaluated the antioxidant property of melatonin in countering the vasospastic effect of oxidized low-density lipoprotein (ox-LDL), which has been reported to be the most important risk factor for atherosclerosis and also may be linked to preeclampsia. Helical sections of umbilical arteries were obtained from human placentas at elective cesarean ...
Gaballa M A - - 2000
The objective of this study was to design a methodology of gene transfer into a resistance vascular bed and to show if such a method can be used to examine the physiological function of a given gene product in vivo. We developed such a method and validated it by defining ...
Stowe F - - 2000
Increased vascular smooth muscle cyclic guanine monophosphate (cGMP) results in vascular relaxation. The vascular effects of stimulating cGMP production with 10(-8)-10(-4) M nitroprusside (NP) and inhibiting cGMP hydrolysis with 10(-8)-10(-4) M zaprinast (ZAP), a selective type V inhibitor of cGMP phosphodiesterase (PDE), were assessed in isolated guinea pig hearts and ...
Kondo U - - 2000
BACKGROUND: The objective was to investigate the effects of propofol anesthesia on the pulmonary vascular response to endothelium-dependent and -independent vasodilators, compared with the responses measured in the conscious state. METHODS: Twenty-six conditioned, male, mongrel dogs were instrumented long-term to measure the left pulmonary vascular pressure-flow relation. Pressure-flow plots were ...
Paredi P - - 2000
Ethane is a product of lipid peroxidation and can be measured in the exhaled air as an index of oxidative stress. Oxidant/antioxidant imbalance is important in the pathogenesis of chronic obstructive pulmonary disease (COPD). Therefore, we measured exhaled ethane in 22 patients with COPD (mean age +/- SEM, 59 +/- ...
Muscará M N - - 2000
Nonsteroidal anti-inflammatory drugs have been reported to exacerbate hypertension. In this study, we tested the hypothesis that a nitric oxide-releasing derivative of naproxen would ameliorate hypertension in the rat. Hypertension was induced by partially occluding one renal artery (the "2K,1C" model), and 2 wk later the rats started receiving naproxen, ...
Wallace J L - - 2000
Nitric oxide (NO) is now recognized as an important modulator of an enormous number of physiological processes, ranging from blood pressure regulation to neuronal transmission to penile erectile function. In the gastrointestinal tract, NO also participates in many physiological and pathophysiological processes. In this review, we summarize the contribution made ...
Megson I L - - 2000
Photorelaxation of vascular smooth muscle (VSM) is caused by the release of nitric oxide (NO) from a finite molecular store that can be depleted by irradiating pre-contracted arteries with visible light. The ability of an 'exhausted' vessel to respond to a further period of illumination is lost temporarily but then ...
Thompson L P - - 2000
BACKGROUND: Estrogen is cardioprotective of the coronary circulation by mechanisms incompletely understood. This study determined the effect of chronic 17beta-estradiol replacement on dilator responses to acetylcholine and sodium nitroprusside of the isolated coronary microcirculation. METHODS AND RESULTS: Adult female guinea pigs were ovariectomized, and a 21-day-release pellet containing 0.0, 0.1, ...
Sakai H - - 2000
The influence of infusion of a nitric oxide (NO) synthase inhibitor, N(omega)-nitro-l-arginine methyl ester (l-NAME), on resistance arteries (diameter, 150 +/- 8 microm) and its relationship with hypertension were examined in conscious hamsters fitted with a dorsal skinfold window. After infusing l-NAME (10 and 30 mg/kg), hamsters showed immediate hypertension ...
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