Search Results
Results 351 - 400 of 1695
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Tamagawa Kazuaki - - 2005
BACKGROUND: It remains unclear whether coronary microvascular response to alpha-adrenergic activation alters in chronic heart failure (CHF). METHODS AND RESULTS: We investigated the alpha-adrenergic receptor-mediated effects on coronary pressure-flow relationship (CPFR) in a tachycardia-induced canine heart failure model. The dogs studied were male (29 of 31) and the drugs were ...
Yang Qin - - 2005
BACKGROUND: Although the detrimental effect of hyperkalemia on coronary endothelium has been reported, there is no direct evidence regarding the effect of hyperkalemic exposure on nitric oxide (NO) release from the coronary endothelium. In addition, it is unclear whether nicorandil, a KATP channel opener, used as hyperpolarizing cardioplegia or added ...
Berges An - - 2005
This study aimed to investigate whether permanent ischaemia influences subacute vasodilatation responses of non-infarcted rat coronary vasculature, and to characterise these coronary changes. Ischaemia led to a significant impairment of the endothelium-dependent vasodilator response, while coronary vasodilatory capacity remained unaltered. In normal coronary circulation, nitric oxide (NO) and prostanoids contributed ...
Takase Hiroyuki - - 2005
The effects of nifedipine on inflammation and endothelial function in the coronary circulation were studied in patients who had angina pectoris (n = 17). Long-term treatment with nifedipine (nifedipine CR, 20 mg/day for 4 months) decreased levels of C-reactive protein in the coronary sinus (from 0.35 +/- 0.09 mg/dl to ...
Anderson Todd J - - 2005
Coronary disease or its risk factors has been reported to attenuate basal nitric oxide (NO) activity. Intravascular ultrasound was used in the present study to better understand this relation. Basal and stimulated NO activities were assessed in 53 stable subjects. Coronary diameter and velocity (0.014-inch Doppler wire) were measured at ...
Ichigi Yoshihide - - 2005
OBJECTIVES: This study was aimed to determine the relationship between pulse pressure (PP) and coronary vasomotor dysfunction, a predictor of coronary events. BACKGROUND: Pulse pressure is a strong risk factor for coronary artery disease (CAD). However, the mechanisms by which an increase in PP affects the pathogenesis of CAD are ...
Tio Ren A - - 2005
Vascular endothelial growth factor (VEGF) is a potent angiogenic factor. VEGF gene therapy improves perfusion of ischemic myocardium in experimental models and possibly in patients with end-stage coronary artery disease. In addition to its proliferative and migratory effect on endothelial cells, it also activates and up-regulates endothelial nitric oxide synthase ...
Suzuki Shoji - - 2005
We compared the effect of an ATP-sensitive potassium channel opener, YM934, with that of nitroglycerin (NTG) on impaired coronary circulation in dogs. Coronary stenosis was produced in 7 dogs by placing a hydraulic occluder around the proximal left circumflex coronary (LCx) artery and abolishing reactive hyperemia to compromise the LCx ...
Vallbracht Katja B - - 2005
BACKGROUND: Viral cardiomyopathy resulting from myocardial virus persistence can be associated with inflammatory immune responses that involve the myocardium and coronary blood vessels. The aim of this study was to investigate the differential impact of myocardial virus persistence and inflammation on endothelial function of the coronary microcirculation. METHODS AND RESULTS: ...
Park Seong Mi - - 2005
This study was done to evaluate changes of microvascular function under cold stimulation by measuring coronary flow velocities (CFVs) in vasospastic angina (VA) patients using transthoracic Doppler echocardiography (TTDE). 14 patients with VA and 15 healthy controls were included. CFVs were measured at the distal left anterior descending coronary artery ...
Mittal N - - 2005
A hemodynamic analysis of coronary blood flow must be based on the measured branching pattern and vascular geometry of the coronary vasculature. We recently developed a computer reconstruction of the entire coronary arterial tree of the porcine heart based on previously measured morphometric data. In the present study, we carried ...
Knudson Jarrod D - - 2005
Obesity is associated with marked increases in plasma leptin concentration, and hyperleptinemia is an independent risk factor for coronary artery disease. As a result, the purpose of this investigation was to test the following hypotheses: 1) leptin receptors are expressed in coronary endothelial cells; and 2) hyperleptinemia induces coronary endothelial ...
Takahashi Katsuaki - - 2005
NO plays an important role in the compensatory increase in coronary flow conductance against myocardial ischemia, and NO bioavailability is impaired in various diseases. We tested the hypothesis that, when NO production is inhibited, vasoconstrictor signals from the ischemic myocardium are unmasked. We investigated the involvement of endothelin type A ...
Burmester Marko D - - 2005
The main concern with the use of the long-acting local anesthetics bupivacaine and ropivacaine is inadvertent IV injection, which exposes the heart to toxic drug concentrations. We tested the hypothesis that these chiral anesthetics exert enantioselective actions on coronary vascular tone, the regulation of which does not involve voltage-gated Na(+) ...
McNulty Patrick H - - 2005
Patients with heart disease are frequently treated with supplemental oxygen. Although oxygen can exhibit vasoactive properties in many vascular beds, its effects on the coronary circulation have not been fully characterized. To examine whether supplemental oxygen administration affects coronary blood flow (CBF) in a clinical setting, we measured in 18 ...
Cox Mitchell W - - 2005
BACKGROUND: The effects of hormone replacement therapy (HRT) on the vascular endothelium have been controversial. In this study, we determined the effects of HRT on endothelium-dependent relaxation in a porcine coronary artery model. METHODS: Coronary artery rings harvested from female swine were incubated as controls or with estrogen (10(-9), 10(-8), ...
Adams Volker - - 2005
BACKGROUND: In patients with stable coronary artery disease, physical exercise training (ET) improves endothelial dysfunction. A potential mechanism mediating the enhanced vasomotor function is a reduced breakdown of endothelium-derived nitric oxide by reactive oxygen species (ROS). The aim of the present study was to analyze the impact of ET on ...
Pasqui A L - - 2005
BACKGROUND AND AIM: Microvascular damage of coronary bed has been considered the main pathogenetic factor of cardiac syndrome X (chest pain, exercise-induced ischemic ST-segment changes and angiographically normal coronary arteries). Previous studies have demonstrated that vascular abnormalities are not confined to the heart, suggesting a peripheral vascular dysfunction. On the ...
Lorkowska Barbara - - 2005
Here we studied direct vasodilation induced by statins in isolated bovine coronary arteries. In rings of coronary bovine arteries preconstricted with prostaglandin F(2 alpha) (3 x 10(-8) - 10(-5)), lovastatin, simvastatin, atorvastatin and cerivastatin (3-30 microM) but not pravastatin induced concentration-dependent vasodilation. Removal of endothelium diminished response to simvastatin, cerivastatin ...
Chia Stanley - - 2005
Hyperhomocysteinaemia is a prothrombotic condition that may cause oxidative endothelial injury and impair endogenous fibrinolysis. Vitamin supplementation enhances endothelial function in hyperhomocysteinaemic patients, but responses in patients with co-existing coronary artery disease have been variable. It is also unknown whether hyperhomocysteinaemia is associated with reduced fibrinolytic responses in patients with ...
Tarutani Yasuhiro - - 2005
Endothelium plays a key role in the regulation of not only vascular tone but also thrombosis and fibrinolysis. Brachial flow-mediated vasodilation (FMD) provides a noninvasive method of assessing coronary endothelial dysfunction. However, no data are available on the relationship between brachial FMD and coronary fibrinolytic activity. Thus, we examined the ...
Nakamura Koki - - 2005
BACKGROUND: There are a number of strategies to restore/preserve endothelial function. We have compared the effects of Cerivastatin (CS) to those of L-arginine (L-ARG) supplementation on the endothelial function of human arterial grafts. METHODS: During coronary artery bypass grafting, specimens of radial artery (RA) and left internal thoracic artery (LITA) ...
Dimitrow PaweĊ‚ Petkow - - 2005
Coronary flow reserve was assessed in a patient with Anderson-Fabry disease complicated by symmetric left ventricular hypertrophy. Coronary flow reserve was measurable in all three major coronary arteries providing an opportunity to compare regional coronary flow reserve from different vascular beds. In this patient all the three vascular beds supplied ...
Takahashi Keiko - - 2005
Endothelium-dependent vasodilation decreases in patients with congestive heart failure (CHF). Whether this decreased vasodilation occurs simultaneously in different vascular beds has not been elucidated. We studied the vasomotor reactivity in both coronary and peripheral resistance vessels in a rat CHF model produced by ligating the left coronary artery. Variations in ...
Chen YingJie Y Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, USA. - - 2005
This study examined whether increased superoxide (O(2)(-).) production contributes to coronary endothelial dysfunction and decreased coronary blood flow (CBF) in congestive heart failure (CHF). To test this hypothesis, the effects of the low-molecular-weight SOD mimetic M40401 on CBF and myocardial oxygen consumption (MVo(2)) were examined in dogs during normal conditions ...
Pedersen Nina G - - 2004
OBJECTIVES: The aim of this study was in an animal model to assess the vascular effects of different progestins commonly used in hormonal replacement treatment. METHODS: Fifty-six non-atherosclerotic, ovariectomized New Zealand white rabbits were randomized into seven groups: (1) medroxyprogesterone acetate (MPA), (2) norethisterone acetate (NETA), (3) conjugated equine estrogens ...
Bonetti Piero O - - 2004
OBJECTIVES: We investigated the value of reactive hyperemia peripheral arterial tonometry (RH-PAT) as a noninvasive tool to identify individuals with coronary microvascular endothelial dysfunction. BACKGROUND: Coronary endothelial dysfunction, a systemic disorder, represents an early stage of atherosclerosis; RH-PAT is a technique to assess peripheral microvascular endothelial function. METHODS: Using RH-PAT, ...
Duncker D J - - 2004
The consistently high level of myocardial oxygen extraction requires tight control of coronary blood flow, because an increase in myocardial oxygen demand, as occurs during exercise, cannot be obtained by a further increase in oxygen extraction. Consequently, adequate control of coronary vascular resistance is critical. Coronary resistance vessel tone is ...
Herrmann Joerg - - 2004
BACKGROUND: Shear stress alteration has been recognized as a predisposing factor for the impairment of endothelial function. Myocardial bridging is a congenital condition associated with alteration in shear stress, however, its impact upon vasoreactivity remains undetermined. METHODS AND RESULTS: This was a case-control designed study with 29 patients with myocardial ...
Blum Arnon - - 2004
We studied 30 consecutive patients who underwent coronary stenting with respect to postprocedure endothelial dysfunction and levels of pre- and postprocedure cytokines. Patients with severe impairment of flow-mediated dependent dilation, but not flow- mediated independent dilation, had higher concentrations of C-reactive protein before percutaneous coronary intervention (12.9 +/- 20.2 vs ...
Pereira Raquel Binda - - 2005
Myocardial infarction (MI) was induced in rats by coronary ligation to compare changes in vascular reactivity from animals that developed heart failure (InfHF) with those that did not (Inf). Infarct size was similar in both groups. In vitro preparations of tail vascular bed were used to investigate the vascular responses ...
Xu Jiang - - 2005
The mechanism of extracellular ATP-triggered vagal depressor reflex was further studied in a closed-chest canine model. Adenosine and ATP were administered individually in equimolar doses (0.01-1.0 mumol/kg) into the right coronary artery (RCA) and left circumflex coronary artery (LCA). When administered into the RCA, adenosine and ATP exerted an identical ...
Barbato Emanuele - - 2004
BACKGROUND: Maximal hyperaemia is paramount in the diagnosis of patients with coronary artery disease. However in these patients, enhanced alpha-adrenergic microvascular vasoconstriction may preclude adenosine to induce maximal hyperaemia. AIM: To assess the presence and the clinical relevance of residual microvascular resistance after administration of adenosine. METHODS AND RESULTS: Fractional ...
Asselbergs Folkert W - - 2004
At present, the value of endothelial function as a prognostic tool has been evaluated only in selected groups of patients with mild or minor coronary artery disease, not in the complete spectrum of patients presenting with angina. The objective of this study was to evaluate whether endothelium-dependent vasodilation of the ...
Di Bello Vitantonio - - 2004
OBJECTIVE: Aims of this study were to: (1) demonstrate whether quantitative myocardial contrast echocardiography could detect an index of myocardial blood flow reserve through the analysis of refilling curves generated by microbubble transit into myocardium both at rest and after vasodilatation induced by dipyridamole; and (2) explore with this method ...
Sawmiller Darrell R - - 2004
The potency and mechanism of action of vasoactive intestinal peptide (VIP) for producing coronary vasodilation was investigated in the isolated perfused heart of the rat. VIP reduced coronary vascular resistance in a dose-dependent manner, starting at 1 x 10(-10) M, and maximally reduced coronary vascular resistance by 49% at 1 ...
Le D E - - 2004
To determine whether, when the vasomotor capacity of the coronary arterioles is exhausted at rest, myocardial blood volume decreases in order to maintain a normal capillary hydrostatic pressure, even at the expense of myocardial oxygen delivery. 18 dogs were studied. In group 1 (n = 9), coronary driving pressure (CDP) ...
Sorajja Paul - - 2004
OBJECTIVE: Although the anticoagulatory properties of hirudin are well known, its direct vasoactive effects have not been investigated extensively. Hirudin stimulates nitric oxide and prostacyclin production in noncoronary vascular beds, but its actions on coronary arteries are unknown. MATERIALS AND METHODS: Five-millimeter segments of canine left circumflex coronary arteries were ...
Pearson Paul J - - 2004
BACKGROUND: Acute rejection, which is a major cause of death after cardiac transplantation, is associated with increased coronary artery resistance and decreased coronary blood flow, leading to congestive heart failure. MATERIALS AND METHODS: To examine the contribution of endothelium-derived vasoactive factors on coronary artery tone during acute rejection, dogs underwent ...
Yang Eric H - - 2004
The purpose of this study was to analyze coronary hemodynamics and determine a possible mechanism for microvascular dysfunction in patients with symptomatic hypertrophic cardiomyopathy (HC). Although patients with HC have been shown to have microvascular dysfunction and reduced coronary flow reserve (CFR), the mechanism by which this occurs is not ...
Herijgers Paul - - 2004
BACKGROUND: Brain death induces myocardial dysfunction and multifocal microscopic myocardial necrosis in dogs; however, the pathogenetic pathways between brain death and cardiac damage remain incompletely understood. We hypothesized that brain death might induce a propensity toward coronary vasospasms, possibly by endothelial dysfunction. We therefore studied the effect of serotonin and ...
Sato Kouichi - - 2004
OBJECTIVE: Coronary microvessels are functionally coupled to the myocardial metabolic state. In hypercholesterolemia, the coronary vascular dysfunction extends to microvascular levels. We hypothesized that the vasodilator signal transduction from ischemic heart is impaired in the coronary microvascular wall of hypercholesterolemia. METHODS AND RESULTS: Rabbits were fed with normal chow (control ...
Kataoka Tetsuro - - 2004
This study assessed the impact of coronary vascular adaptive remodeling and coronary vascular reactivity on myocardial ischemia in patients with hypertension and left ventricular hypertrophy. Myocardial ischemia is associated with impaired endothelium-independent vasodilation of resistance coronary arteries and increased minimal coronary resistance. These changes may occur in association with lumen ...
Sun Dong - - 2004
Our previous studies have demonstrated that a decrease in arteriolar diameter that causes endothelial deformation elicits the release of nitric oxide (NO). Thus we hypothesized that cardiac contraction, via deformation of coronary vessels, elicits the release of NO and increases in coronary flow. Coronary flow was measured at a constant ...
Boutsianis Evangelos - - 2004
OBJECTIVE: To assess the feasibility of computationally simulating intracoronary blood flow based on real coronary artery geometry and to graphically depict various mechanical characteristics of this flow. METHODS: Explanted fresh pig hearts were fixed using a continuous perfusion of 4% formaldehyde at physiological pressures. Omnipaque dye added to lead rubber ...
Ballo Piercarlo - - 2004
AIMS: To analyse whether heart rate may affect the efficacy of adenosine, verapamil and carotid sinus massage in terminating symptomatic episodes of paroxysmal supraventricular tachycardia (PSVT) in adults. METHODS AND RESULTS: The study population was selected among 175 adult patients, affected by symptomatic PSVT. One hundred and six of them ...
Monnink S H J - - 2004
Coronary vasomotor function plays an important role in onset and progression of coronary artery disease. Suwaidi [Circulation 101 (2000) 948] and Schächinger [Circulation 101 (2000) 1899] demonstrated that vasomotor dysfunction has a significant impact on events in patients with minimal coronary artery disease. Endothelial specific testing can be performed in ...
Rosales Oscar R - - 2004
Adenosine is an endogenous nucleoside available for the diagnosis and treatment of various cardiovascular conditions. It may be given for pharmacologic stress tests as well as administered directly into the coronary arteries during cardiac catheterization. The latter treatment may be utilized to measure fractional flow reserve in addition to treating ...
Jones Richard D - - 2004
Recent clinical studies have reported that testosterone therapy reduces myocardial ischaemia in men with coronary artery disease, and the beneficial modulation of coronary vascular tone by testosterone has been proposed as an effector mechanism. Maintenance of a correct response to vasoconstrictive and vasodilatory agents is essential in the control of ...
Teragawa H - - 2004
OBJECTIVE: To determine how C reactive protein (CRP), a sensitive marker of inflammation, is related to coronary endothelial function. DESIGN: Changes in quantitative coronary angiographic findings and Doppler flow velocity measurements in response to locally infused acetylcholine were assessed. SETTING: Tertiary cardiology centre. PATIENTS: 46 patients with angiographically normal coronary ...
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