Search Results
Results 901 - 950 of 1225
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Curtis J - - 1996
OBJECTIVE: To determine whether tolazoline reduces pulmonary vascular resistance (PVR) by means of endogenous nitric oxide production. DESIGN: Thirty newborn lambs (2 to 7 days of age) were anesthetized with pentobarbital, and their lungs were ventilated through an endotracheal tube. Intravascular catheters were placed in the left ventricle, descending aorta, ...
Tomita T - - 1995
1. Shear stress and flow influence endothelial functions to stimulate the release of endothelium-derived relaxing factor (EDRF). However, it is not well defined how hypertension affects endothelial functions. In this study, blood pressure-related changes of endothelium-dependent relaxation (EDR) in the aorta were examined in SHRSP, WKY and F1 hybrid at ...
Benzing A - - 1995
BACKGROUND: In acute lung injury, when pulmonary microvascular permeability is enhanced, transvascular fluid filtration mainly depends on pulmonary capillary pressure. Inhaled nitric oxide has been shown to decrease pulmonary capillary pressure. Therefore, the effect of inhaled nitric oxide at a concentration of 40 ppm on pulmonary transvascular albumin flux was ...
Persson M G - - 1995
1. The aim of the present study was to investigate the role of nitric oxide (NO), histamine and leukotrienes in bronchial obstruction. For this, guinea-pigs immunised against ovalbumin were studied under anaesthesia during challenge with antigen or agonists. 2. Challenge with nebulised antigen (0.1-1 mg) elicited dose-dependent increases in insufflation ...
Takahashi H - - 1995
In order to clarify the mechanism of hypertension induced by a nitric oxide (NO) synthase inhibitor, L-NG-nitro-L-arginine (LNNA), metabolites of NO, catecholamines, and hemodynamic parameters were measured during 7 days of oral administration of LNNA in rats. Control rats received either L-arginine (L-Arg) or the vehicle. systolic blood pressure, measured ...
Sasaki F - - 1995
1. This study investigated the effects of chronic treatment with carvedilol, a beta-blocking agent with an alpha-blocking activity, on blood pressure, endothelium-dependent relaxation and the endothelial structure of the mesenteric resistance artery in stroke-prone spontaneously hypertensive rats (SHRSP). 2. Chronic treatment with carvedilol at a dose range of 30-120 mg/kg ...
García C E - - 1995
Patients with essential hypertension have abnormal endothelium-dependent vasodilation related to decreased nitric oxide activity. The specific mechanism responsible for this abnormality is unknown. Recent studies in hypertensive animals have suggested an augmented destruction of nitric oxide by superoxide anions. Therefore, in the present study we aimed to investigate whether this ...
Koifman B - - 1995
OBJECTIVES: The aim of this study was to evaluate the hemodynamic effect of L-arginine infusion in patients with congestive heart failure. BACKGROUND: Endothelium-dependent vasodilation is impaired in patients with congestive heart failure. Nitric oxide, which was identified as endothelium-derived relaxing factor, is generated by nitric oxide synthase from L-arginine. Our ...
Bergeron R J - - 1995
The impact of the antineoplastic polyamine analogues N1N14-diethylhomospermine (DEHSPM) and N1N11-diethylnorspermine (DENSPM) on the blood pressure and heart rate of normotensive and hypertensive rats are described. DEHSPM was administered to both normotensive and spontaneously hypertensive rats (SHR), while the DENSPM analogue was given only to the normotensive animals. The intravenous ...
Witte K - - 1995
OBJECTIVES: The study was performed in order to elucidate whether or not the nitric oxide-guanylyl cyclase system is involved in the circadian regulation of blood pressure. METHODS: Basal and sodium nitroprusside-stimulated guanylyl cyclase activity was studied in vitro in aortic tissue from normotensive Wistar-Kyoto rats sacrificed at 7 circadian times. ...
Qiu C - - 1995
Acute nitric oxide blockade not only potentiates the vasoconstrictor actions of endothelin but also enhances the synthesis and release of endothelin. To investigate whether the vasoconstrictor actions of acute nitric oxide blockade are modulated by endothelin, studies were conducted in the conscious, chronically catheterized rat. Renal function was measured before ...
Hou J - - 1995
These studies were performed to determine if the effects of angiotensin II infusion on the development of cardiac fibrosis could be modified by the chronic inhibition of nitric oxide synthase activity. NG-nitro-L-arginine-methyl ester (L-NAME) was administered to adult Wistar rats in drinking water (40 mg/kg per d). Although blood pressure ...
Solzbach U - - 1995
In 11 open-chest dogs with a flowmeter on the left circumflex artery, L-NMMA, a selective inhibitor of nitric oxide-formation, was subselectively infused into the left circumflex artery at a rate of 2.5 mg/ml (ml/min) to avoid systemic hemodynamic effects. The coronary blood flow at normal arterial blood pressure was similar ...
Küng C F - - 1995
Nitric oxide is an important regulator of vascular function and blood pressure. Chronic administration of nitric oxide inhibitors provides a new model of hypertension with pronounced target organ damage. We investigated the effects of oral treatment with N omega-nitro-L-arginine methyl ester (L-NAME) for 6 weeks on vascular reactivity of the ...
Wanna F S - - 1995
The effects of aspirin and L-arginine (biological precursor of nitric oxide) on the production of hydroxyl radicals, cyclic guanosine monophosphate levels, vascular tone, and the recovery of the ischemic myocardium were investigated in isolated rat hearts subjected to ischemia and reperfusion. After 30 minutes of perfusion, hearts were arrested with ...
Moreau P - - 1995
BACKGROUND AND PURPOSE: Nitric oxide is an important regulator of vascular tone and may also be implicated in the modulation of vascular growth and structure. This study presents the effects of chronic nitric oxide inhibition, with or without antihypertensive treatment, on the structure and function of the basilar artery in ...
Clarkson P B - - 1995
1. Nitric oxide is recognised as an important biological mediator, which is thought to be involved in cardiovascular homeostasis. The purpose of this study was to investigate the effects of basal nitric oxide synthesis on cardiac function in man, by blocking nitric oxide synthesis with NG-monomethyl-L-arginine (L-NMMA). 2. Eight normal ...
Castellano M - - 1995
OBJECTIVE: To examine the cardiovascular effects of acute systemic nitric oxide synthesis inhibition in humans in relation to the possible involvement of changes in sympathetic nervous system activity or in the baroreceptor reflex. DESIGN: Placebo or NG-monomethyl-L-arginine (250 mg by intravenous infusion for 5 min) was administered to seven healthy ...
Ihnken K - - 1995
This study tests the interaction between oxygen tension and cardioplegic composition on nitric oxide production and oxidant damage during reoxygenation of previously cyanotic hearts. Of 35 Duroc-Yorkshire piglets (2 to 3 weeks, 3 to 5 kg), six underwent 30 minutes of blood cardioplegic arrest with hyperoxemic (oxygen tension about 400 ...
Kojda G - - 1995
Recent evidence indicates that organic nitrate esters may directly affect heart muscle. In the present study we investigated the effects of the new organic nitrate ester, N-(3-nitratopivaloyl)-1-cysteineethylester (SPM3672), on isolated adult rat ventricular myocytes and on Langendorff preparations of spontaneously beating rat hearts perfused in a volume-constant manner. In cardiomyocytes ...
Utepbergenov D I - - 1995
Derivatives of 3,4-dihydro-1,2-diazete 1,2-dioxides (DD) have been investigated as NO donors in vitro and in vivo. Using nitronylnitroxides as spin traps for NO, these compounds were shown to decompose in water solutions at physiological pH and temperature, producing two molecules of NO per one DD molecule. Rate constants of DD ...
Forrest E H - - 1995
It has been proposed that the hyperdynamic circulation found in cirrhosis is mediated by nitric oxide released through the induction of nitric oxide synthase. To investigate this the effect of the nitric oxide synthase inhibitor, NG-monomethyl-L-arginine (L-NMMA), was studied upon the portal circulation. After a 30-min infusion of 3 mg/kg ...
Gidday J M - - 1995
Isoflurane-anesthetized newborn pigs were used to test the hypothesis that nitric oxide mediates autoregulatory dilations of retinal arterioles. Fundus images were monitored by videomicroscopy at x310, and stimulus-induced changes in retinal arteriolar diameter were measured by on-line image analysis. Dilatative responses to systemic hypoxia (arterial O2 tension 20-30 mmHg), hypotension ...
Haworth S G - - 1995
Normal adaptation to extra-uterine life consists of an immediate increase in endothelial and smooth muscle cell (SMC) surface: volume ratio as the cells 'spread' in the vessel wall. Lumen diameter increases and resistance falls. Changes in SMC shape are associated with a transient depolymerization of contractile and cytoskeletal filaments. The ...
Wieczorek K M - - 1995
OBJECTIVE: Our purpose was to determine the effect of perfusate flow or viscosity on release and action of nitric oxide in the human fetal-placental vasculature in vitro. STUDY DESIGN: Cotyledons from normal term placentas were perfused with Hanks' buffered saline solution gassed with 95% oxygen and 5% carbon dioxide, pH ...
Gordon J B - - 1995
Both increases and decreases in endothelium-derived nitric oxide (EDNO) activity have been described in the developing pulmonary vasculature. We hypothesized that differences in baseline vasomotor tone and/or oxygen tension may contribute to this variability. Pulmonary arterial dose responses to endothelium-dependent and -independent vasodilators acetylcholine (ACh) and sodium nitroprusside (SNP), respectively, ...
Amrani M - - 1995
OBJECTIVE: To evaluate the effect of L-arginine, the physiological substrate of nitric oxide (NO), upon coronary flow (CF) and mechanical function during reperfusion following cardioplegic arrest. METHODS: Two groups of isolated rat hearts were subjected to cardioplegic arrest for 4 h at 4 degrees C. In group 1 (n = ...
Dunn W R - - 1995
OBJECTIVE: To examine the effects of hypertension induced by chronic inhibition of nitric oxide synthase with NG-nitro-L-arginine methyl ester (L-NAME) on the structure of mesenteric resistance arteries. DESIGN AND METHODS: Brattleboro rats were given L-NAME (0.01-0.05 mg/ml, equivalent to 10-50 mg/kg per day) in their drinking water for 2-3 weeks. ...
Hussain S N - - 1995
We assessed the role of nitric oxide (NO) in the regulation of diaphragmatic O2 uptake (Vo2di) and phrenic vascular resistance during endotoxemia in anesthetized, mechanically ventilated dogs. Left diaphragmatic vasculature was isolated and briefly pump perfused with arterial blood at a normal flow rate, at a high rate (50% higher ...
Goldman A P - - 1995
BACKGROUND: Severe pulmonary hypertension is still a cause of morbidity and mortality in children after cardiac operations. The objective of this study was to compare the vasodilator properties of inhaled nitric oxide, a novel pulmonary vasodilator, and intravenous prostacyclin in the treatment of severe postoperative pulmonary hypertension. METHODS: Thirteen children ...
Castillo L - - 1995
Despite the potential relevance of the L-arginine-nitric oxide (NO) pathway in the pathophysiology of pulmonary hypertension, no in vivo studies of the kinetics of arginine and NO have been conducted previously in this population. The terminal guanidino N-atom of L-arginine is the precursor for NO, which is oxidized to the ...
Hedner J - - 1995
This paper deals with the potential role of two blood pressure regulatory systems in the development of hypertension in obstructive sleep apnoea (OSA). Beside the acute and long-term sympathoexcitation documented in this disease, there seems to be an impaired endothelium-dependent vascular relaxation. In particular, nitric oxide (NO)-mediated vasodilatation was impaired ...
Inglés A C - - 1995
The present study was designed to investigate the possible role of endothelium-derived vasodilators, nitric oxide and prostaglandins, in the regulation of blood pressure during the presence and absence of the major pressor systems. Conscious rats were infused with a cocktail of inhibitors of the sympathetic nervous system, renin-angiotensin system, and ...
Adatia I - - 1995
OBJECTIVES: We investigated the effect of inhaled nitric oxide and infused acetylcholine in patients with pulmonary hypertension undergoing cardiac catheterization before cardiopulmonary transplantation. BACKGROUND: The fate of patients under consideration for transplantation of the heart or lungs, or both, is influenced by the evaluation of their pulmonary vascular reactivity. METHODS: ...
Macdonald A G - - 1995
Nitrous oxide reversibly affects the kinetics, but not the conductance, of the qGluR channel of locust muscle. 0.5 atm N2O at 20.5 degrees C was without effect but both 1.5 and 2.7 atm significantly reduced the probability of the channel opening, the frequency of opening and the mean open time, ...
Weitzberg E - - 1995
OBJECTIVE: To evaluate the possible effects of a combination of systemic nitric oxide synthesis inhibition (to increase mean arterial blood pressure) and nitric oxide inhalation (to decrease pulmonary vascular pressure) in porcine endotoxin shock. DESIGN: Prospective trial. SETTING: Laboratory at a large university medical center. SUBJECTS: Ten pathogen-free pigs weighing ...
Kieler-Jensen N - - 1995
BACKGROUND: Vasodilator therapy is frequently needed to treat pulmonary hypertension after heart transplantation. In the present study, the effects of intravenous sodium nitroprusside, prostacyclin, prostaglandin E1, and inhaled nitric oxide (5, 10, and 20 parts per million) on central hemodynamics, right ventricular function, and pulmonary selectivity were evaluated shortly after ...
Mitaka C - - 1995
To elucidate the role of nitric oxide (NO) in septic shock, we measured hemodynamic and pulmonary gas changes in anesthetized dogs after intravenous administration of bacterial lipopolysaccharide (LPS) with or without NO synthase inhibitor, NG-nitro-L-arginine (L-NNA). Infusion of LPS (250 ng.kg-1.min-1) for 2 h decreased mean arterial pressure over 1-4 ...
Hashida-Okumura A - - 1995
Bovine adrenals were found to contain a factor that activates neuronal nitric oxide synthase (NOS) and reduces the blood pressure when injected into the lateral cerebral ventricle (LCV). This factor showed chemical and functional characteristics similar to flavin adenine dinucleotide (FAD). Therefore, the effect of FAD on neuronal NOS activity ...
Gattullo D - - 1995
In the coronary bed vasodilation can be mediated by several mechanisms including endothelium-produced nitric oxide. To examine the contribution of nitric oxide, three different techniques to cause vasodilation in the coronary vessels were used in the anaesthetized dog: intracoronary injection of 1 microgram acetylcholine, sudden reduction of the aortic blood ...
Bührer C - - 1995
In acute hypoxemic respiratory failure of term and near-term neonates, extra- and intrapulmonary right-to-left shunting contribute to refractory hypoxemia. Inhaled nitric oxide (NO) decreases pulmonary arterial pressure and improves ventilation-perfusion mismatch in a variety of animal models and selected human patients. We report on 10 consecutive term and near-term newborns ...
Ventura S - - 1995
Graded caval occlusion in conscious rabbits caused a biphasic response. Phase I was characterized by a fall in conductance so that arterial pressure was maintained. When cardiac output had fallen to 71 +/- 4% of its baseline level, phase II supervened. During phase II, conductance rose abruptly and arterial pressure ...
Ichinose F - - 1995
Inhaled nitric oxide (NO) has been shown to selectively dilate the pulmonary vasculature. Zaprinast, an inhibitor of guanosine 3',5'-cyclic monophosphate-specific phosphodiesterase, augments smooth muscle relaxation induced by endothelium-dependent vasodilators. The present study was designed to determine whether intravenous administration of Zaprinast potentiates the vasodilating effects or prolongs the duration of ...
Nozik E S - - 1995
L-Arginine is the substrate for synthesis of nitric oxide (NO.) by NO synthase which physiologically produces vasodilation. The reaction of NO. or its metabolites with O2 or its metabolites, however, can produce toxic reactive species which may cause cellular injury. We hypothesized that excessive NO. production in isolated perfused rabbit ...
Sigmon D H - - 1995
We have reported that in two-kidney, one clip hypertensive rats, renal perfusion is maintained by a balance between the vasodilator endothelium-derived nitric oxide and the vasoconstrictor angiotensin II. Others have suggested that endothelium-derived constricting factor, reported to be thromboxane A2 and/or endoperoxide, contributes to increased blood pressure in angiotensin II-dependent ...
Bohn H - - 1995
1. This study examines the cardiovascular effects of CAS 1609 (4-hydroxymethyl-furoxan-3-carboxamide) in vitro as well as in vivo in various animal models. 2. CAS 1609 relaxed guinea-pig pulmonary artery strips without endothelium with IC50-values of 0.9 microM (phenylephrine contracted) and 15 microM (KCl-depolarized). This effect was inhibited by oxyhaemoglobin. In ...
Cobb J P - - 1995
We studied the differential hemodynamic effects of N omega-monomethyl-L-arginine (L-NMMA), an inhibitor of nitric oxide (NO) synthesis, in normal and endotoxemic dogs and examined its activity across the venous, pulmonary, and systemic circulations. Survival was used to determine therapeutic efficacy. In both normal and endotoxemic animals, L-NMMA similarly increased systemic ...
Nakamoto H - - 1995
New studies suggest that vasodilator systems may play an important role in restraining the rise in peripheral vascular resistance associated with the evolution of arterial hypertension. We characterized in conscious dogs the hemodynamic and hormonal effects of 4 weeks of feeding either the nitric oxide synthase inhibitor N omega-nitro-L-arginine (3 ...
Fakler C R - - 1995
Endogenous nitric oxide produced from L-arginine is a potent vasodilator that may be involved in blood pressure regulation. A male infant with argininosuccinate lyase deficiency, who could not synthesize L-arginine, was hypertensive prior to L-arginine replacement. The infusion of L-arginine resulted in a decrease in blood pressure. A three-fold increase ...
Gao X P - - 1995
The purpose of this study was to determine whether short-term exposure of resistance arterioles to lipopolysaccharide in situ is associated with changes in vasomotor tone. Using intravital microscopy, we found that suffusion of Escherichia coli lipopolysaccharide (3 micrograms/ml) over hamster cheek pouch arterioles for 1 h was associated with a ...
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