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Douglas S A - - 2000
The novel cyclic undecapeptide human urotensin-II (hU-II) and its high-affinity G-protein-coupled receptor, GPR14, are both expressed within the human cardiovasculature (vascular smooth muscle, endothelium, myocardium, coronary atheroma, etc.) and may, therefore, contribute to the (patho)physiological regulation of cardiovascular homeostasis in humans. Indeed, hU-II is an efficacious, sustained spasmogen of mammalian ...
Chen J W - - 2000
The relationship between coronary hemodynamics and left ventricular contractility was studied in 20 patients with syndrome X. Among them, 10 patients with a resting left ventricular ejection fraction (LVEF, by radionuclide method) equal to or greater than the mean value of the whole group (58%) were defined as having relative ...
Garcia F C - - 2000
OBJECTIVE:To examine the effects of long-term high-altitude hypoxia on the contractile properties of isolated fetal coronary arteries. METHODS: Maximal contractile responses (T(max)) to 90 mmol/L KCl and the thromboxane A(2) mimetic U46619 were measured in proximal (PLCx) and distal left circumflex (DLCx), left anterior descending (LAD), and right coronary arterial ...
Afulukwe I F - - 2000
The role of nitric oxide (NO) in lipopolysaccharide (LPS)-induced myocardial dysfunction remains controversial as some investigators concluded that inhibition of NO synthesis improves left ventricular (LV) contractility, whereas others did not. We investigated the relationship between LPS-induced LV dysfunction and LV NO production. We postulated that high myocardial NO concentrations ...
Schwinger R H - - 2000
The mode of action of Crataegus extracts in the treatment of heart failure is still under examination. WS 1442, a standardized special extract from Crataegus leaves with flowers, exerts direct positive inotropic effects. This study was designed to investigate the mode of inotropic action of WS 1442 in human myocardium ...
Heusch G - - 2000
Patients with chronic coronary artery disease frequently have contractile dysfunction that recovers upon reperfusion. The concept of myocardial hibernation views the observed reduction in contractile function not as the result of an ongoing energetic deficit, but as an adaptive down-regulation that serves to maintain myocardial integrity and viability. In the ...
Alpert N R - - 2000
In failing human hearts (FHH) (NYHA IV) the cardiac output is inadequate to meet the metabolic needs of the peripheral systems. By means of thermo-mechanical analysis we have shown that epicardial strips from FHH (37 degrees C) have a depressed tension independent heat (TIH) and tension independent heat rate (dTIH ...
Leone R J RJ - - 2000
We hypothesized that myocardial stunning would be reversed through increased cyclic GMP caused by nitroprusside, and that this would be accomplished through a decreased proportion of regional work during diastole. Hearts were instrumented to measure left ventricular pressure, and regional myocardial mechanics were recorded using a miniature force transducer and ...
Miyaji K - - 2000
BACKGROUND: Evaluation of regional myocardial contractile function is of clinical importance. We have developed a new tactile sensor system for accurate measurement of myocardial stiffness in situ. We found that the myocardial stiffness measured by this sensor, which we call tactile stiffness, can be a very useful index for accurate ...
Effat M - - 2000
In 10 patients with atrial fibrillation, echocardiographic measures of left ventricular function-interval relations were used to assess contractility and to test the hypothesis that rhythm regularization produces a higher contractile state than is seen when the rhythm is irregular. Regularization, following direct-current cardioversion, did not augment ventricular contractility above that ...
Marian A J - - 2000
Myocardial contractility is generally believed to be increased in hypertrophic cardiomyopathy. I propose the opposite--that cardiac myocyte contractility is decreased in this disorder. Accordingly, the contractile deficit provides the primary stimulus for increased expression of trophic factors in the heart, which leads to hypertrophy, interstitial fibrosis, and other phenotypes. Variation ...
Rouet-Benzineb P - - 1999
End-stage of human dilated cardiomyopathy (DCM) is characterized by myocyte loss and fibrosis, and associated with ventricular dilatation and reduced cardiac function. Matrix metalloproteinases (MMPs) and their natural tissue inhibitors (TIMPs) have been involved in the myocardial remodeling. To evaluate the potential role of matrix gelatinases (MMP-2 and MMP-9) in ...
Prabhu S D - - 1999
As the precise role of nitric oxide (NO) as a modulator of myocardial contraction and the force-interval relationship remains unclear, the objective of this study was to examine the effect of the NO donor S-nitroso-N-acetyl-penicillamine (SNAP) on baseline myocardial contraction, and the impact of both SNAP and the NO synthase ...
Cross H R - - 1999
Cardiac beta(2)-adrenergic receptor (beta(2)AR) overexpression is a potential contractile therapy for heart failure. Cardiac contractility was elevated in mice overexpressing beta(2)ARs (TG4s) with no adverse effects under normal conditions. To assess the consequences of beta(2)AR overexpression during ischemia, perfused hearts from TG4 and wild-type mice were subjected to 20-minute ischemia ...
Ren J - - 1999
Accumulating evidence has indicated that insulin-like growth factor-1 (IGF-1) plays a specific role in the intricate cascade of events of cardiovascular function, in addition to its well established growth-promoting and metabolic effects. IGF-1 is believed to mediate many effects of growth hormone (GH), IGF-1 promotes cardiac growth, improves cardiac contractility, ...
Heusch G - - 1999
During normoperfusion, both myocardial blood flow and contractile function are heterogeneously distributed throughout the left ventricle. Midwall segment shortening is greater at the apex than at the base of the left ventricle, and greater in the anterior than in the posterior wall. Also, transmural heterogeneity of myocardial deformation exists, with ...
Segawa D - - 1999
Cardiac effects of clevidipine, a new ultrashort-acting dihydropyridine Ca2+ channel antagonist were investigated in Langendorff-perfused rat hearts and compared to those of nifedipine and isradipine. The aim was to determine and compare the negative inotropic vs. chronotropic potency of these drugs. The hearts were perfused with oxygenated Krebs-Henseleit buffer at ...
Hoffmann J N - - 1999
Myocardial dysfunction due to sepsis is common in patients with multiple organ dysfunction syndrome and is believed to be produced by inflammatory mediators. Some of these mediators may be eliminated by continuous hemofiltration, which is a standard procedure in an ICU for renal replacement therapy. This study was designed to ...
Ramesh G - - 1999
Increased Plasma Nitrite Level in Cardiac Failure. Nitric oxide is implicated in the pathogenesis of cardiac failure. Plasma nitrite level (an end product of nitric oxide metabolism) is studied in 15 patients of chronic rheumatic valvular heart disease with myocardial contractile dysfunction and cardiac failure (Group I), 15 patients of ...
Janssen P M - - 1999
Functional studies of different human cell types have been successfully conducted under in vitro conditions. Despite many efforts, it has not been possible to develop a human myocardial preparation in which contractile function can be studied over several days. We hypothesize that by mimicking the in vivo situation in an ...
Upton R N - - 1999
The myocardial kinetics of meperidine and the relationship between these kinetics and the effect of meperidine on myocardial contractility (maximum positive rate of change of left ventricular pressure) were examined by analysis of previously published data collected in sheep after the i.v. injection of 100 mg of meperidine over 1 ...
MacFarlane N G - - 1999
This study aimed to determine structural alterations occurring in cardiac myofilaments after exogenous application of oxidants and the effects of oxidants on contractile protein function in a rabbit coronary artery ligation model of heart failure. Myocardial "stiffness" was higher in the ligated animals (Lig) than sham-operated controls (Sh, 4.9+/-1.5 versus ...
Hatcher C J - - 1999
Ablation of the cardiac neural crest (CNCA) in embryonic chicks results in a high incidence of persistent truncus arteriosus, a congenital heart defect associated with decreased myocardial contractility. Using left ventricular trabeculae from chicks at embryonic day (ED) 15, we have previously shown that the twitch force of intact preparations ...
Ritchie R H - - 1999
1. During septic shock, myocardial contractile dysfunction is accompanied by the release of cytokines and enhanced production of nitric oxide, and the contractile dysfunction is prevented by glucocorticoids. 2. Myocardial dysfunction was induced in vitro by incubation of rat papillary muscle for 15 h with endotoxin (lipopolysaccharide, LPS) and interferon-gamma ...
Schmidt C - - 1999
BACKGROUND: Propofol's unique pharmacokinetic profile offers advantages for titration and rapid emergence in patients after coronary artery bypass graft (CABG) surgery, but concern for negative inotropic properties potentially limits its use in these patients. The current study analyzed the effect of various propofol plasma concentrations on left ventricular (LV) contractility ...
Kypson A - - 1999
Gene transfer to modify donor heart function during transplantation has significant therapeutic implications. Recent studies by our laboratory in transgenic mice have shown that overexpression of beta2-adrenergic receptors (beta2-ARs) leads to significantly enhanced cardiac function. Thus, we investigated the functional consequences of adenovirus-mediated gene transfer of the human beta2-AR in ...
Mercuro G - - 1999
We studied myocardial contractility by pulsed wave Doppler tissue imaging in 6 postmenopausal healthy women. According to a crossover, double-blind protocol, we randomized patients to treatment with transdermal patches of estradiol-17beta or matched placebo. Estradiol-17beta did not modify local systolic and diastolic functions. Thus, at least when acutely administered, estrogen ...
van der Velden J - - 1999
OBJECTIVE: In this study we investigated whether differences exist or develop in patients with aortic or mitral valve disease in myofibrillar contractile function and contractile protein composition between subendo- and subepicardial human ventricular tissue. Isometric tension, its calcium sensitivity and contractile protein composition were studied in left ventricular subendo- and ...
Owen V J - - 1999
BACKGROUND: Potential cardiac donors show various degrees of myocardial dysfunction, and the most severely affected hearts are unsuitable for transplantation. The cause of this acute heart failure is poorly understood. We investigated whether alterations in calcium-handling proteins, beta-adrenoceptor density, or the inhibitory G protein Gialpha could account for this phenomenon ...
Melvin D B - - 1999
Reducing a dilated left ventricle's radius by wedge resection lowers wall stress, improving performance. However, compliance falls, stroke volume improvement is limited, and, later, both functional deterioration and serious dysrhythmias are frequent. These all may result from loss of circumference, loss of contractile mass, and myocardial trauma, none of which ...
Kraut E J - - 1999
BACKGROUND: Depression of myocardial contractility occurs in septic shock. METHODS: Fourteen pigs were instrumented to measure cardiopulmonary dynamics after a challenge of Escherichia coli endotoxin (lipopolysaccharide endotoxin, LPS). A volumetric Swan-Ganz catheter was placed via the jugular vein, and a carotid arterial line was placed into the aortic root. Eight ...
Patel MK - - 1999
BACKGROUND: Palmitoyl carnitine accumulation during ischemia causes profound electrophysiological changes, resulting in arrhythmias. We studied the electrophysiological and contractile effects of palmitoyl carnitine. METHODS AND RESULTS: Extracellular recordings made by using the endocardial unipolar paced evoked response (PER) in isolated perfused rabbit hearts were compared with action potentials (AP) recorded ...
Kojda G - - 1999
The effects of exogenous and endogenous. NO on myocardial functions such as contraction, relaxation and heart rate have recently gained considerable scientific interest. .NO stimulates myocardial soluble guanylate cyclase to produce cGMP, which activates two major target proteins. A small increase in cGMP levels predominantly inhibits phosphodiesterase III, while high ...
Nagashima Y - - 1999
PURPOSE: The effects of propofol on sinoatrial pacemaker activity and myocardial contractility and its interaction with the autonomic nervous system were investigated in isolated, cross-circulated right atrial canine preparations. METHODS: An isolated right atrial preparation was perfused with heparinized arterial blood from an anesthetized support dog and changes in atrial ...
Cittadini A - - 1999
Until a few years ago, growth hormone (GH) and insulin-like growth factor-1 (IGF-1) were considered essential only to the control of linear growth, glucose homeostasis, and for the maintenance of skeletal muscle mass. A large body of evidence recently coming from animal and human studies has unequivocally proven that the ...
Brochet E - - 1998
OBJECTIVES: The purpose of this study was to assess early temporal changes in myocardial perfusion pattern by myocardial contrast echocardiography (MCE) and their relation to myocardial viability in patients with reperfused acute myocardial infarction (AMI). BACKGROUND: Myocardial contrast echocardiography no-reflow is associated with poor contractile recovery after AMI. However, little ...
Mariotti E - - 1998
Iron-induced cardiac disease is the primary cause of death in transfused patients with thalassaemia major. The beneficial effects of deferoxamine mesylate on clinical cardiac disease have been well described but the impact of therapy on subclinical cardiac dysfunction is unknown. To assess the reversibility of subclinical cardiac dysfunction we studied ...
Lee S - - 1998
Recently we have shown that the left ventricular end-systolic pressure-volume relation (ESPVR) of in situ rat hearts is an upward convex curve in contrast to the linear left ventricular ESPVR in dog and human hearts. Within the smaller left ventricular volume range, the left ventricular end-systolic pressure rose steeply with ...
McDonough K H - - 1998
Previous studies have demonstrated that sepsis, endotoxin, and cytokine administration cause myocardial dysfunction. Nitric oxide has been implicated in this dysfunction, since in isolated cardiac tissues, dysfunction is prevented when nitric oxide synthase (NOS) inhibitors are present. To determine whether nitric oxide produced by the inducible form of the enzyme ...
Meguro T - - 1998
The effects of verapamil administration or vagal stimulation on the mechanical restitution curve (MRC) were studied in order to better understand the modulation of left ventricular (LV) function by interventions that lower the ventricular rate of atrial fibrillation. The MRC and the postextrasystolic MRC were obtained in 11 dogs using ...
Natale E - - 1998
The influence of the calcium antagonist gallopamil on the contractility of asynergic viable myocardium after acute myocardial infarction treated with thrombolysis was investigated by two-dimensional echocardiography. Sixteen patients with > or = 1 viable segment(s), identified during the low-dose phase (up to 10 micrograms/kg/min) of a dobutamine echocardiographic test (up ...
Müllner M - - 1998
After successful resuscitation from cardiac arrest, prolonged contractile failure has been demonstrated in animal experiments. No systematic evaluation of myocardial contractility following successful resuscitation after human cardiac arrest exists. The aim of this study was to assess left ventricular contractility following human cardiac arrest with successful resuscitation. In 20 adult ...
Grupp I L - - 1998
The stimulation of cardiac alpha1-adrenergic receptors (AR) modulates the heart's inotropic response and plays a role in the induction of cardiomyocyte hypertrophy. We have analyzed transgenic mouse lines overexpressing a wild-type alpha1B-AR specifically in the heart. Basal level systolic and diastolic left ventricular (LV) contractile function was depressed both in ...
Schelbert H R - - 1998
Therapeutic approaches to left ventricular dysfunction in ischemic heart disease are likely to be guided by the answers to 2 major questions: (1) which mechanisms account for the deterioration or loss of contractile function, and (2) can contractile function be improved or restored therapeutically? Both questions can face considerable diagnostic ...
Heusch G - - 1998
When severe ischemia, such as that resulting from a sudden and complete coronary artery occlusion, is prolonged for more than 20-40 min, myocardial infarction develops, and there is irreversible loss of contractile function. When myocardial ischemia is less severe but nevertheless prolonged, the myocardium is dysfunctional but can remain viable. ...
New R B - - 1998
BACKGROUND: Because of methods required for obtaining isolated left ventricular myocytes, evaluation of the contractile function of isolated left ventricular myocytes in normal human patients has been limited. Accordingly, the goal of the present study was to develop a means to isolate human left ventricular myocytes from small myocardial biopsy ...
Baer F M - - 1998
During the past decade there has been intense clinical interest in the differentiation between scar tissue and postischemic viable myocardium and its relevance to patient treatment and outcome. Frequently used paradigms of myocardial viability are hibernation and stunning which both refer to reversible left-ventricular contraction impairment. Hibernation describes the concomitant ...
Rivera E S - - 1998
OBJECTIVES: This study sought to evaluate the effects of veno-venous ultrafiltration on myocardial contractility in children undergoing cardiopulmonary bypass (CPB) for repair of congenital heart defects. BACKGROUND: Ultrafiltration (UF) is currently used to diminish postoperative fluid accumulation following CPB in children. Previous reports indicate improvement in hemodynamics immediately after UF, ...
von Spiegel T - - 1998
Myocardial pump function and the performance of the entire cardiovascular system are determined by preload, afterload and contractility. The best clinical measure of preload is the end-diastolic volume of the heart, which can be assessed by ventriculography, echocardiography or by indicator dilution techniques. Afterload is basically the wall tension during ...
Panas D - - 1998
Proinflammatory cytokines (interleukin-1beta, tumor necrosis factor-alpha, and interferon-gamma; Cytomix) depress myocardial contractile work partially by stimulating expression of inducible nitric oxide (NO) synthase (iNOS). Because NO and peroxynitrite inhibit myocardial O2 consumption (MVO2), we examined whether this mechanism contributes to reduced cardiac work. In control isolated working rat hearts, cardiac ...
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