Search Results
Results 451 - 500 of 1700
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Rzeczuch Krzysztof - - 2003
BACKGROUND: Induction of maximal hyperaemia is a prerequisite for a reliable estimation of fractional flow reserve (FFR) in a moderate coronary artery stenosis. Intracoronary adenosine is the most frequently used agent to achieve maximal hyperaemia. However, an insufficient dose of adenosine may induce only partial hyperaemia, thus artificially increasing the ...
Talukder M A Hassan - - 2003
To clarify which adenosine receptor subtype(s) are responsible for regulation of coronary flow through endogenous adenosine, coronary vascular responses were examined in isolated hearts from wild-type (WT) and A(2A) knockout (A(2A)KO) mice. Adenosine deaminase inhibitor, erythro-9-hydroxy-nonyl-adenine (EHNA), and adenosine kinase inhibitor, iodotubericidine (ITU), were used to examine the effects of ...
Sezgin Alpay Turan - - 2003
BACKGROUND: Slow coronary flow (SCF) in a normal coronary angiogram is a well-recognized clinical entity, but its etiopathogenesis remains unclear. DESIGN: The aim of the study was to determine endothelial function in patients with SCF using a flow-mediated dilatation (FMD) technique in the brachial artery. METHODS: Coronary flow was quantified ...
Asanuma Hiroshi - - 2003
Celiprolol is a selective beta(1)-adrenoceptor antagonist with antihypertensive actions, which causes renal vasodilation by increasing tissue nitric oxide (NO) levels. The authors tested whether celiprolol increases coronary blood flow (CBF) by increasing cardiac NO release in the ischemic heart in vivo. In open-chest dogs, coronary perfusion pressure of the left ...
Perrault Louis P - - 2003
BACKGROUND: The endothelium protects the vascular wall through the nitric oxide (NO) release. Coronary endothelial dysfunction occurs early after heart transplantation and predicts the development of intimal thickening typical of graft coronary vasculopathy. OBJECTIVE: We designed this study to examine the effect of endothelial NO synthase (eNOS) inhibition on the ...
Shioiri Hiroki - - 2003
An increase in coronary flow conductance during acidosis is an important compensatory mechanism in various diseased conditions. On the other hand, hypercholesterolemia causes microvascular dysfunction as well as macrovascular disorders. We investigated the impact of hypercholesterolemia on the coronary microvascular response to acidosis. Coronary arterioles (< 150 microm) isolated from ...
Massicotte Julie - - 2003
AIM: Lercanidipine is a new vasoselective dihydropyridine calcium channel blocker with a short plasma half-life, long duration of action, and demonstrated cardioprotective properties. We hypothesized that it might be effective at attenuating the adverse impact observed on the coronary compartment and myocardium in the transition phase to heart failure in ...
Chen Jaw-Wen - - 2003
Recent evidence suggests that myocardial ischemia may occur in patients with neurally mediated syncope and normal coronary angiograms. This study was conducted to evaluate if coronary microvascular function is impaired in such patients. Coronary hemodynamic studies and head-up tilt table tests (HUTs) were performed on 30 consecutive patients with normal ...
Furuyama Hideto - - 2003
OBJECTIVES: Coronary arterial lesions after Kawasaki disease (KD) may cause coronary endothelial dysfunction as the result of intimal hypertrophy. Our purpose was to assess myocardial flow reserve (MFR) and endothelial function in various myocardial regions after KD by using positron emission tomography. STUDY DESIGN: Twenty-seven patients, 17.2 +/- 3.2 years ...
Chenevard Rémy - - 2003
BACKGROUND: There is an ongoing debate as to whether the gastrointestinal safety of COX-2 inhibition compared with nonsteroidal antiinflammatory drugs (NSAIDs) may come at the cost of increased cardiovascular events. In view of the large number of patients at cardiovascular risk requiring chronic analgesic therapy with COX-2 inhibitors for arthritic ...
- - 2003
BACKGROUND: Endothelial dysfunction is an important feature of atherosclerosis. Inhibition of the HMG-CoA pathway and of calcium channels improves endothelial function experimentally and in the forearm circulation. Thus, we investigated the effects of a statin and/or a calcium antagonist on coronary endothelial function in patients with coronary artery disease (CAD). ...
Tomanek Robert J - - 2003
The development of the heart is closely linked to its temporally and spatially regulated vascularization. Hypoxia has been shown to stimulate myocardial capillary growth and improve myocardial perfusion during reperfusion in postnatal animals exposed to chronic or intermittent exposure to hypobaria. Vascular endothelial growth factor (VEGF) is up-regulated by hypoxia ...
Katz S D - - 2003
Endothelial dysfunction is associated with impairment of aerobic capacity in patients with heart failure and may play a role in the progression of disease. Impaired endothelium-dependent vasodilation in patients with heart failure can be attributed to decreased bioavailability of nitric oxide and attenuated responses to nitric oxide in vascular smooth ...
Demaria Roland G - - 2003
BACKGROUND: A new penetrating stapled anastomotic system using nitinol microclips (Coalescent Surgical U-Clip) has been developed to facilitate the construction of compliant interrupted sutures for minimally invasive and robotic surgery as well as for conventional procedures. The purpose of this study was to determine the effect of nitinol U-Clips used ...
Bouyer-Dalloz F - - 2003
The frequent exposure of the heart to radiation during thoracic tumor radiotherapy often results in chronic impairment of myocardial function. The aim of the present investigation was to evaluate the effect of irradiation on coronary vascular tone in rat hearts exposed in vivo to a single dose of 20 Gy ...
Kjaer Andreas A Department of Clinical Physiology and Nuclear Medicine, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. - - 2003
Much evidence suggests endothelial dysfunction to be present in non-insulin-dependent diabetes mellitus (NIDDM) and to be important for the development of myocardial ischemia. Endothelial function in the coronary vessels may be studied in various ways. We compared the effect of cold pressor testing (CPT) with that of dipyridamole, a pharmacologic ...
Marzilli Mario - - 2002
We designed a study to explore the effect of glycoprotein (GP) IIb/IIIa blockade on the atherosclerotic plaque and distal coronary vasculature. Platelet GP IIb/IIIa blockers have been proven to be beneficial in acute ischemic syndromes. This effect has also been attributed to the prevention of microvascular obstruction, although the underlying ...
Heloire François - - 2002
Coronary effects of Ca -channel blockers mibefradil and amlodipine were compared in conscious dogs. Ten dogs were instrumented for measurement of aortic and left ventricular pressures, circumflex coronary blood flow velocity (CBFv), and coronary diameter (CD). A permanent catheter was implanted in the circumflex coronary artery. At doses having no ...
Gillies Hunter C - - 2002
Sildenafil citrate is the first oral phosphodiesterase type 5 inhibitor approved for the treatment of erectile dysfunction. The wide use of sildenafil by patients with erectile dysfunction and cardiovascular disease has resulted in a considerable number of independent studies investigating the cardiovascular safety and functional role of the phosphodiesterase type ...
Yoneyama Masahiko - - 2002
Colforsin daropate is a recently developed water-soluble derivative of forskolin that directly stimulates adenylate cyclase, unlike the catecholamines. The chronotropic, inotropic and coronary vasodilator actions of colforsin daropate were compared with those of isoproterenol, dopamine and dobutamine, using canine isolated, blood-perfused heart preparations. The stimulating effect of each drug on ...
Pugh Peter J - - 2002
Administration of testosterone to men with angina has been shown to reduce myocardial ischemia. The mechanism of this effect is not clear but could be via an influence on coronary artery tone. We therefore employed an animal model to study the intrinsic responses of coronary arteries mounted in the wire ...
Merkus Daphne - - 2002
Coronary tone is determined by a balance between endogenously produced endothelin and metabolic dilators. We hypothesized that coronary vasodilation during augmented metabolism is the net result of decreased endothelin production and increased production of vasodilators. Isolated rat myocytes were stimulated at 0, 200, and 400 beats/min to modify metabolism. Supernatant ...
Halcox Julian P J - - 2002
OBJECTIVE: We studied the effects of sildenafil, a phosphodiesterase 5 inhibitor, on coronary and peripheral vascular function, platelet activation, and myocardial ischemia. BACKGROUND: Nitric oxide vasodilates and inhibits platelet activation by generating cyclic guanosine 5'-monophosphate, which is metabolized by phosphodiesterase type 5. METHODS: The effect of oral sildenafil on resting ...
Lee Tsung-Ming - - 2002
BACKGROUND: Distension of the urinary bladder reflexly causes a change of coronary vasomotor response. The effect of such distension on the coronary circulation in hyperlipidemic patients, a condition with impaired endothelial function, remains unknown. HYPOTHESIS: We tested the hypothesis whether urinary bladder distension caused an exaggerated vasomotor response of epicardial ...
Baschat A A - - 2002
Prenatal ultrasound today allows the detailed study of small caliber vascular beds including the fetal coronary arteries and the coronary sinus. The coronary circulation is unique because of its critical role in myocardial metabolism and function and its ability to adapt in many fetal conditions. The ultrasound examination techniques for ...
Bendall Jennifer K - - 2002
Numerous studies in the literature have employed gene-modified mice to investigate vascular function. However, only very limited information exists on baseline murine vascular physiology or on potential variations between different strains. We therefore compared coronary and aortic vascular responses to endothelium-derived vasodilators and exogenous nitric oxide (NO) in three commonly ...
Perrault Louis P - - 2002
BACKGROUND: The nonworking heterotopic heart transplantation model has been used extensively for the study of rejection and coronary endothelial function in different species. The effect of left ventricular loading in a working heart transplantation model, which may be associated with different coronary flow patterns and local nitric oxide release, on ...
Kunze S - - 2002
Coronary oxygen persufflation may serve as a means to improve storage conditions and organ preservation time for cardiac transplantation. We examined whether coronary oxygen persufflation and prolonged preservation time alter the endothelium-dependent relaxation of isolated coronary arteries. Isolated rabbit hearts were subjected to four different protocols: control (no preservation), 3 ...
Edmundowicz Daniel - - 2002
Noninvasive vascular imaging may identify the high-risk, asymptomatic atherosclerotic patient who will substantially benefit from aggressive preventive therapies. Endothelium is a key player in the early stages of atherogenesis. Positron emission tomography (PET) and ultrasound-measured brachial artery vasoreactivity have emerged as potentially useful tools for the identification of endothelial dysfunction ...
Mershon John L - - 2002
Estrogen is believed to protect postmenopausal women from coronary vascular disease, in part by increasing production of nitric oxide (NO). In this study, we investigated the possibility that transcriptional activation of inducible NO synthase (iNOS) is responsible for a component of the estrogen-induced increase in coronary blood flow. Twenty-two ewes ...
Ulker Sibel - - 2002
OBJECTIVE: The non-specific serine protease inhibitor aprotinin is currently used to reduce blood loss and the need for blood transfusion after cardiopulmonary bypass. We have recently reported that aprotinin impairs endothelium-dependent but not endothelium-independent relaxations in rat thoracic aortic rings due to its inhibitory effect on endothelial nitric oxide (NO) ...
Petersen Henrik H HH Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, Canada V6T - - 2002
Hypertrophic cardiac myopathy (HCM) is the leading cause of mortality in young athletes. Abnormalities in small intramural coronary arteries have been observed at autopsy in such subjects. The walls of these intramural vessels, especially in the ventricular septum, are thickened, and the lumen frequently appears narrowed. Whether these morphological characteristics ...
Gokce Noyan - - 2002
OBJECTIVES: The goal of this study was to investigate whether concomitant therapy with vasoactive medications alters the results of noninvasive assessment of endothelial function. BACKGROUND: Ultrasound assessment of brachial artery flow-mediated dilation is emerging as a useful clinical tool. The current practice of withholding cardiac medications before ultrasound studies has ...
Kyriakides Zenon S - - 2002
Endothelin (ET) exerts a tonic, stiffening effect on the common carotid artery in rats in vitro. This effect is mediated via the ET(A) receptor. The aim of this study was to examine the acute effects of ET(A) receptor antagonism on coronary artery compliance in humans. We examined 22 patients with ...
Martínez Maria Angeles - - 2002
To examine coronary reactivity to acetylcholine and endothelin-1 (ET-1) during partial ischaemia and reperfusion, flow in the left circumflex coronary artery was measured electromagnetically, and coronary partial ischaemia was induced by stenosis of this artery in anaesthetized goats. In eight animals not treated with N(G)-nitro-l-arginine methyl ester (l-NAME), coronary stenosis ...
Fernández Nuria - - 2002
The coronary effects of endothelin-1 (ET-1) during acute hypertension were examined in anesthetized goats, where the left circumflex coronary artery flow was electromagnetically measured and hypertension was induced by constriction of the thoracic aorta. In six non-treated goats, aortic constriction increased arterial pressure (mean arterial pressure=128+/-5 mmHg) and coronary flow ...
Murakami Yo - - 2002
1. Nicorandil is a potent vasodilator combining the effects of a nitrate with an ATP-sensitive potassium channel (K(ATP)) opener. Because the postinfarct remodelled heart has increased vulnerability to subendocardial hypoperfusion, it is possible that the vasodilator effects of nicorandil could cause transmural redistribution of blood flow away from the subendocardium. ...
Sun Dong - - 2002
BACKGROUND: The exact role of adrenoceptors in norepinephrine (NE)-mediated regulation of the human coronary circulation has yet to be elucidated. Thus, the goals of this study were to characterize the adrenoceptors involved in the responses to NE in isolated human coronary arterioles and small arteries. METHODS AND RESULTS: Arterioles (n=39) ...
Kitakaze Masafumi - - 2002
OBJECTIVES: We examined whether the combination of an angiotensin-converting enzyme (ACE) inhibitor and an angiotensin II receptor blocker (ARB) synergistically mediates coronary vasodilation and improves myocardial metabolic and contractile dysfunction in ischemic hearts. BACKGROUND: Either an ACE inhibitor or ARB mediates coronary vasodilation in ischemic hearts. METHODS: In dogs with ...
Beaucage Pierre - - 2002
Although studies have reported that increase in coronary perfusion (CP) results in positive inotropic effects, the underlying mechanisms of these actions and possible alterations in myocardial diastolic function are not well defined. Hypothesis was that nitric oxide (NO) and derivatives of cytochrome (CYT) P-450 or cyclooxygenase (COX) might contribute to ...
Thornburg Kent L - - 2002
The determinants of coronary flow in the heart were studied using the chronic near-term fetal sheep model. Coronary flows were measured using implanted Doppler probes on the fetal circumflex artery calibrated with radiolabelled microspheres. Experiments were conducted to calculate maximal coronary flow under conditions of systolic work, chronic, and acute ...
He Guo-Wei - - 2002
BACKGROUND: We have investigated and compared nitric oxide (NO) release and endothelium-derived hyperpolarizing factor (EDHF)-mediated hyperpolarization in the human internal mammary artery (IMA), radial artery (RA), saphenous vein (SV), and coronary artery. MATERIALS AND METHODS: Vessel segments taken from coronary artery bypass grafting or heart transplantation patients were placed in ...
Flood Amanda J - - 2002
OBJECTIVES: To assess the impact of ischemia-reperfusion (I/R) on coronary function, and the role of endogenous adenosine in modifying post-ischemic vascular function in asanguinous hearts. METHODS: Vascular function was studied in Langendorff perfused mouse hearts subjected to 20-25-min ischemia and 30-min reperfusion. RESULTS: Ischemia altered the dependence of flow on ...
Ungvari Zoltan - - 2002
Hyperhomocysteinemia (HHcy) is a newly recognized risk factor for myocardial infarction, however, the effect of HHcy on endothelium-dependent flow-induced dilation of coronary arteries is not known. Thus, changes in diameter of small intramural coronary arteries (diameter, approximately 145 microm) isolated from control rats and rats with methionine diet-induced HHcy were ...
Nikolaidis Lazaros A - - 2002
BACKGROUND: ACE inhibitors have been used extensively in heart failure, where they induce systemic vasodilatation. ACE inhibitors have also been shown to reduce ischemic events after myocardial infarction, although their mechanisms of action on the coronary circulation are less well understood. The purpose of the present study was to determine ...
Sato Kouichi - - 2002
OBJECTIVES: We sought to detect cross-talk between the beating heart and coronary vascular bed during myocardial ischemia and to test the hypothesis that the cross-talk is mediated by pertussis toxin (PTX)-sensitive G proteins (G(PTX)) in vessels. BACKGROUND: Coronary flow is closely related to the myocardial metabolic state, indicating the existence ...
Neglia Danilo - - 2002
The aim of the current study was to assess the ability of amlodipine to dilate the coronary vessels in subjects with angiographically normal coronary arteries and normal left ventricular function. Ten patients, six women and four men (mean age 48 +/- 14 years, range 25-67 years) were enrolled. Coronary flow ...
Tsai Jang-Zern - - 2002
We used a four-terminal plunge probe to measure myocardial resistivity in two directions at three sites from the epicardial surface of eight open-chest pigs in-vivo at eight frequencies ranging from 1 Hz to 1 MHz. We calibrated the plunge probe to minimize the error due to stray capacitance between the ...
Bots Michiel L - - 2002
BACKGROUND: ACE inhibition reduces morbidity and mortality among a variety of patients. Among mechanisms explaining these beneficial effects are the effects on the sympathetic system and on local vasodilating substances such as nitric oxide and bradykinins at the level of the endothelium. The PERFECT study was designed to verify the ...
Minamino Tetsuo - - 2002
Accumulated evidence suggests that several drugs proven to improve survival in patients with chronic heart failure (CHF) enhance endogenous nitric oxide (NO)- and/or adenosine-dependent pathways. Indeed, we and others have demonstrated that: i) antagonists of either renin-angiotensin-aldosterone or beta-adrenergic systems enhance NO-dependent pathways; ii) although carvedilol and amlodipine belong to ...
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