Search Results
Results 601 - 650 of 1130
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van der Velden J - - 2002
In failing human myocardium changes occur, in particular, in isoform composition and phosphorylation level of the troponin T (TnT) and troponin I (TnI) subunits of the actin filament and the myosin light chains (MLC-1 and -2), but it is unclear to what extent they influence cardiac performance. This overview concentrates ...
de Simone Giovanni - - 2002
In all conditions altering wall stress and mechanical stretching, LV performance becomes insufficient at the distance, due to a number of structural and functional alterations ultimately impairing pump function, but not invariably due to reduced inotropic state. Among them, structural alteration of the normal myocardial architectures might play a key ...
Jacob R - - 2002
In the early years after foundation (1927) of the German Society for Circulation Research, physiological topics were often predominant at the annual meetings. At that time, besides methodological questions of blood pressure measurement, sphygmography and phonocardiography, many lectures and discussions were concerned with problems of electrocardiogaphy, the transmitters and effects ...
Pósa Ildikó - - 2002
The effects of glibenclamide (GB, CAS 10238-21-8) and those of the latest low daily dose sulphonylurea compound, glimepiride (GM, CAS 93479-97-1) on myocardial haemodynamics and pyruvate-lactate metabolism of healthy and alloxan-diabetic dogs (n = 6 in six groups) were compared. Mean arterial blood pressure, heart rate, blood flow of the ...
Bi Xiaojun - - 2002
To evaluate the effects of left ventricular contractility on the changes of average image intensity (AII) of the myocardial integrated backscatter (IB) and cyclic variation in IB (CVIB), 7 adult mongrel dogs were studied. The magnitude of AII and CVIB were measured from myocardial IB carves before and after dobatamine ...
Brunner F - - 2001
BACKGROUND: The major source of nitric oxide (NO) in the heart is the constitutive form of NO synthases (eNOS, NOS III) that is expressed in vascular endothelium and cardiac myocytes. NO mediates endothelium-dependent vasodilation and may modulate cardiac function. We examined the role of NO in hearts from transgenic (TG) ...
Alipov N N - - 2001
The possibility of using contraction and relaxation indices for evaluation of inotropic and loositropic influences on the heart was studied in experiments on cats. Increased pre- and afterload were used as the stimuli, which are simultaneously loading and reflexogenic. Under conditions of preserved innervation both stimuli elevated the indices selected ...
Schulz R - - 2001
During normoperfusion, both contractile function and myocardial blood flow are heterogeneously distributed throughout the left ventricle. Midwall segment shortening is greater at the apex than at the base of the left ventricle, and it is greater in the anterior than in the posterior wall. Also, transmural heterogeneity of myocardial deformation ...
Dinarello C A - - 2001
BACKGROUND: Interleukin 18 (IL18) is related to the IL1 family by structure, receptors, signalling molecules, and function. IL18 induces gene expression and synthesis of tumour necrosis factor (TNF), IL1, Fas ligand, several chemokines, and vascular adhesion molecules. Similar to IL1beta, IL18 is synthesised as a biologically inactive precursor molecule lacking ...
Karsanov N V - - 2001
Experiments with hybrid myocardial fibers showed that abnormalities of actin (basic protein of fine sarcomer threads) are responsible for reduced contraction rate, decreased developed force, and low efficiency of cardiomyocyte contraction in chronic heart failure caused by dilatation and ischemic cardiomyopathies and infective allergic myocarditis. Wastefulness of the contractile process ...
Ambrosio G - - 2001
The phenomenon of myocardial stunning has been observed in all animal species studied. The possible occurrence of myocardial stunning in man has been demonstrated after either regional ischemia (such as exercise-induced angina, vasospastic or unstable angina) or after global ischemia (i.e., after cardioplegic arrest during cardiac surgery, or cardiac arrest, ...
Mizukoshi Y - - 2001
PURPOSE: We have previously observed that sympathetic blockade by epidural anesthesia (EA) modifies the cardiovascular response to marked hypercapnic acidosis in dogs. Our objective was to determine whether the combination of marked hypercapnic acidosis and EA reduce left ventricular contractility. METHODS: We randomly assigned 22 Japanese white rabbits anesthetized with ...
Hamada K - - 2001
The purpose of the following experiment was to determine whether amelioration of myocardial contractile dysfunction by diltiazem is mediated by shortening of monophasic action potential duration (MAPD) during myocardial ischemia in anesthetized dogs. Diltiazem improved regional contraction during reperfusion after 10-min occlusion. The shortening of MAPD and increase in [K+]e ...
Lancellotti P - - 2001
OBJECTIVES: To assess the relative value of electrocardiographic, echocardiographic, angiographic, and in-hospital therapeutic indices for predicting late functional recovery after acute myocardial infarction, and to determine the variables associated with absence of recovery, partial recovery, and full recovery. DESIGN: Prospective observational follow up study. SETTING: Teaching hospital. PATIENTS: 74 consecutive ...
Di Bello V - - 2001
Ultrasonic myocardial tissue characterization represents a relatively new diagnostic tool which allows integration of the conventional echocardiographic evaluation, in order to obtain specific textural parameters which reflect the myocardial ultrastructural texture. In particular, through this approach it is possible to obtain two different types of information: the first is static ...
Takuma S - - 2001
It is well known that the level of anesthesia obtained by intraperitoneal injection is variable and may alter cardiac function. In this study, we compared the effects of different anesthetics on cardiac function with the conscious state using high-resolution two-dimensional echocardiography in nonischemic and ischemic mice. Eighty-four mice were tested ...
Arthur W - - 2001
For over 40 years the measurement of intracardiac impedance has been proposed as a method of assessing the contractile state of the heart muscle. This technique requires the positioning of one or more intracavitary electrodes and the generation of an electric field from an alternating current source. Variations in the ...
Pomerantz B J - - 2001
The proinflammatory cytokine IL-18 was investigated for its role in human myocardial function. An ischemia/reperfusion (I/R) model of suprafused human atrial myocardium was used to assess myocardial contractile force. Addition of IL-18 binding protein (IL-18BP), the constitutive inhibitor of IL-18 activity, to the perifusate during and after I/R resulted in ...
Schotten U - - 2001
BACKGROUND: After cardioversion of atrial fibrillation (AF), the contractile function of the atria is temporarily impaired. Although this has significant clinical implications, the underlying cellular mechanisms are poorly understood. METHODS AND RESULTS: Forty-nine consecutive patients submitted for mitral valve surgery were investigated. Twenty-three were in persistent AF (>/=3 months); the ...
Muro T - - 2001
OBJECTIVE: To clarify whether assessment of the acoustic properties of the myocardium at rest can predict contractile reserve in patients with chronic left ventricular dysfunction. METHODS: 23 patients (mean (SD) age 63 (12) years) with chronic left ventricular dysfunction were studied. The magnitude of cardiac cycle dependent variation of integrated ...
Nagahama Y - - 2001
Echocardiographic techniques were used to measure left ventricular isovolumic and ejection phase indexes of contractility in 54 patients with atrial fibrillation, and the relations between cycle lengths and contractility were compared in patients with normal and depressed ejection fractions. Data indicate that variations in contractility occur in a pattern that ...
Rivenes S M - - 2001
BACKGROUND: The cardiovascular effects of halogenated anesthetic agents in children with normal hearts have been studied, but data in children with cardiac disease are limited. This study compared the effects of halothane, isoflurane, sevoflurane, and fentanyl-midazolam on systemic and pulmonary hemodynamics and myocardial contractility in patients with congenital heart disease. ...
Grandel U - - 2001
OBJECTIVE: Myocardial depression, which frequently occurs in the course of septic shock, has been attributed to the cardiodepressant properties of nitric oxide (NO) generated by either the inducible NO synthase (iNOS) or the constitutive isoform (cNOS). We have previously demonstrated that alpha-toxin from Staphylococcus aureus induces thromboxane-mediated vasoconstriction accompanied by ...
Russell F D - - 2001
The effects of the recently identified human peptide urotensin-II (hU-II) were investigated on human cardiac muscle contractility and coronary artery tone. In right atrial trabeculae from non-failing hearts, hU-II caused a concentration-dependent increase in contractile force (pEC(50)=9.5+/-0.1; E(max)=31.3+/-4.8% compared to 9.25 mM Ca(2+); n=9) with no change in contraction duration. ...
Knollmann B C - - 2001
The cardiac troponin T (TnT) I79N mutation has been linked to familial hypertrophic cardiomyopathy and a high incidence of sudden death, despite causing little or no cardiac hypertrophy. In skinned fibers, I79N increased myofilamental calcium sensitivity (Miller, T., Szczesna, D., Housmans, P. R., Zhao, J., deFreitas, F., Gomes, A. V., ...
Paulus W J - - 2000
Modulation by NO of systolic myocardial function received widespread attention but most studies focused on potential negative inotropic properties of NO. The very original observations on the effects of NO on myocardial contraction already provided evidence that NO modified myocardial contractile performance mainly through a relaxation-hastening effect (i.e. earlier onset ...
Shan K - - 2000
BACKGROUND: Alterations in adrenergic receptor densities can potentially contribute to myocardial dysfunction. Their relevance to myocardial hibernation in humans is unknown. METHODS AND RESULTS: Accordingly, 22 transmural myocardial biopsies were obtained in 11 patients with ischemic ventricular dysfunction during bypass surgery, guided by transesophageal echocardiography. Patients underwent dobutamine echocardiography (DE) ...
Stangl V - - 2000
The effects of adrenomedullin in the regulation of myocardial contractility were investigated in the rat. In papillary muscles (n=6), adrenomedullin (0.1 to 10 nM) failed to show contractile effects. NO (nitric oxide) synthase inhibition with N(G)-nitro-L-arginine (L-NOARG) did not unmask any inotropic effect of adrenomedullin. The positive inotropic effect of ...
Kapelko V I - - 2000
The purpose of the study was to explore effects of prolonged caffeine administration on the contractile function and myocardial energy metabolites of the isolated rat heart. Caffeine treatment for 1 week (10 mg/kg, i.p., twice a day) was followed by unchanged pump function of the isolated heart, but reduced maximal ...
Zaloga G P - - 2000
OBJECTIVE: To investigate the direct and indirect effects of the anorexic agent phenylpropanolamine (PPA) on the heart and to determine whether nitric oxide deficiency exacerbates the myocardial toxicity of PPA. DESIGN: Dose response effects using sequential drug administration. SETTING: Animal research laboratory of a large tertiary academic medical center. SUBJECTS: ...
Dhein S - - 2000
In human right atrium, endothelin A (ET(A)) receptors couple to both inositol phosphate formation and inhibition of adenylylcyclase, whereas in human left ventricle, ET(A) receptors couple only to inositol phosphate formation. To find out whether this might be of functional relevance, we studied, in right atria obtained from 32 patients ...
de Groot S H - - 2000
BACKGROUND: In dogs, chronic complete atrioventricular block (CAVB) results in structural (biventricular hypertrophy) and electrical (delayed repolarization) remodeling, which predisposes the heart to torsade de pointes arrhythmias. We assessed the contractile alterations in the CAVB dog and tested the hypothesis that these adaptations increase delayed afterdepolarization (DAD)-dependent triggered arrhythmias. METHODS ...
Canty J M JM - - 2000
Identification of myocardial viability is of increasing clinical importance in managing patients with coronary artery disease and advanced left ventricular dysfunction. Although viable chronically dysfunctional myocardium is always the result of repetitive episodes of reversible ischemia, there may be multiple mechanisms responsible for the contractile dysfunction. Many patients have contractile ...
Trines S A - - 2000
There is no evidence regarding the effect of stunning on maximization of regional myocardial external work (EW) or efficiency of energy transfer (EET) in relation to regional afterload (end-systolic stress, sigma(es)). To that end, we studied these relationships in both the left anterior descending coronary artery (LADCA) and left circumflex ...
Ferdinandy P - - 2000
Proinflammatory cytokines depress myocardial contractile function by enhancing the expression of inducible NO synthase (iNOS), yet the mechanism of iNOS-mediated myocardial injury is not clear. As the reaction of NO with superoxide to form peroxynitrite markedly enhances the toxicity of NO, we hypothesized that peroxynitrite itself is responsible for cytokine-induced ...
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, ...
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