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Results 401 - 450 of 1123
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Horiguchi Hiroshi - - 2009
In this paper, we proposed to utilize a reconstructed cardiac tissue as microactuator with easy assembly. In a glucose solution, cardiomyocytes can contract autonomously using only chemical energy. However, a single cardiomyocyte is not enough to actuate a microrobot or a mechanical system. Though the output power will increase by ...
Pantos Constantinos - - 2010
Thyroid hormone (TH), apart from its "classical" actions on cardiac contractility and heart rhythm, appears to regulate various intracellular signalling pathways related to response to stress and cardiac remodelling. There is now accumulating experimental and clinical evidence showing a beneficial effect of TH on limiting myocardial ischaemic injury, preventing/reversing post ...
Shen Weiqun - - 2010
Myocardial [ATP] falls in the failing heart. One potential compensatory mechanism for maintaining a near normal free energy of ATP hydrolysis (DeltaG approximately (ATP)), despite a fall in [ATP], may be the reduction of myocardial creatine (Cr). To test this, we conducted a longitudinal study using transgenic mice overexpressing cardiac ...
Ma Heng - - 2010
1. Cisplatin is a potent chemotherapeutic agent with broad-spectrum antineoplastic activity against various types of tumours. However, a major factor limiting treatment with cisplatin is its acute and cumulative cardiotoxicity. The aim of the present study was to explore the effect of cisplatin on myocardial contractile function and the possible ...
Naiyanetr Phornphop - - 2010
BACKGROUND: The clinical application of rotary blood pumps (RBPs) for bridge-to-recovery and destination therapy has focused interest on the remaining contractile function of the heart and its course. This study reports a method to determine contractility that uses readily measured variables of the RBP. METHOD: The proposed index (I(Q)) is ...
Cz??bel Mikl??s - - 2009
The role of endogenous nitric oxide (NO) in modulating myocardial contractility is still unclear, in part because of unknown, secondary effects of blocking NO release. We hypothesized that the nonspecific inhibition of nitric oxide synthase (NOS) enhances endothelin-1 (ET-1) effects, which can play a role in ET-A receptor-dependent myocardial contractile ...
Sharman James E - - 2009
Augmentation index (AIx), a correlate of mortality, is thought to be influenced by left ventricular contractility and wave reflections. However, the relationship of AIx with left ventricular contractility changes has never been assessed, and the wave reflection theory has recently been questioned. This study sought to examine arterial waveform changes ...
Nalivaiko Eugene E School of Biomedical Sciences, University of Newcastle, Newcastle, NSW 2308, Australia. - - 2010
A great deal of knowledge exists regarding neural control of myocardial function in the rat. Most of the studies addressing this issue were conducted either under general anaesthesia or in isolated hearts in vitro. Our principal aim was to provide a detailed quantitative description of mechanisms controlling cardiac contractility in ...
Borlaug Barry A - - 2009
We sought to compare left ventricular (LV) systolic stiffness and contractility in normal subjects, hypertensive patients without heart failure, and patients with heart failure and preserved ejection fraction (HFpEF) and to determine whether LV systolic stiffness or myocardial contractility is associated with the rate of mortality in patients with HFpEF. ...
Krasniqi A - - 2009
The toxic effect of alcohol on the heart was recognized long time ago. The aim of our study was to evaluate the cardiodepressive effect of alcohol in our in-patients and compare the obtained results with those in the literature. The study included 187 patients (184 men and 3 women) aged ...
Go Orson - - 2009
Myocardial stunning refers to contractile dysfunction that persists after an ischemic episode and restoration of coronary blood flow. In this article, 2 cases of myocardial stunning after electroconvulsive therapy in patients with an apparently normal heart are presented. The incidence of this condition is unknown. It is observed that this ...
Black Adam - - 2009
The search for a load-independent index of myocardial contractility has been a focus for nearly 100 years. Nearly all of the parameters developed have yielded insight into cardiac function but their clinical utility has been limited. A new index, dsigma*/dt (max), has been proposed to be useful in the clinic. ...
Hidalgo Rosa María Vivanco RM Servicio de Neurología, Unidad de Neurovascular, Hospital del Mar, Barcelona, - - 2009
In patients with stroke, atrial fibrillation is an independent risk factor and indicates a poor prognosis. Cardiac monitoring is carried out for longer periods in stroke units. The aim of this study was to determine the frequency at which atrial fibrillation is detected in stroke units and the percentage of ...
Denk Katja - - 2009
OBJECTIVE: The present study was performed as an attempt to analyze the relationship between body weight and human myocardial performance. As overweight is frequently associated with hypertension, stenosis of epimyocardial coronary arteries and other factors that influence myocardial performance, the experimental model of isolated human atrial myocardium was selected. Atrial ...
Cerra M C - - 2009
Being the largest form of intravascular and tissue storage of nitric oxide (NO) and a signalling molecule itself, the nitrite anion (NO(2)(-)) has emerged as a key player in many biological processes. Since the heart is under an important NO-mediated autocrine-paracrine control, in mammals the cardiac effects of nitrite are ...
Pellegrino Daniela - - 2009
The ubiquitous anion nitrite (NO(2)(-)) has recently emerged as an endocrine storage form of nitric oxide (NO) and a signalling molecule that mediates a number of biological responses. Although the role of NO in regulating cardiac function has been investigated in depth, the physiological signalling effects of nitrite on cardiac ...
Meder Benjamin - - 2009
Although it is well known that mutations in the cardiac essential myosin light chain-1 (cmlc-1) gene can cause hypertrophic cardiomyopathy, the precise in vivo structural and functional roles of cMLC-1 in the heart are only poorly understood. We have isolated the zebrafish mutant lazy susan (laz), which displays severely reduced ...
Patangay Abhilash - - 2009
Acute myocardial infarction (AMI) is one of the leading causes of death in the US. While heart rate variability (HRV) has been widely studied for ischemia detection, the changes in cardiac contractility variability have not yet been explored. This paper presents novel variability analysis using 23 linear and non-linear measures ...
Vanderschuren Abel - - 2009
The authors describe the clinical course of a 50-year-old woman who presented with life-threatening cardiac dysfunction after aneurysmal subarachnoid hemorrhage (Fisher Grade 4). The pathophysiology of cardiac injury in this setting is not fully understood, but excess sympathetic activation can lead to neurogenic stressed myocardium. A metabolic intervention using the ...
Etemadi Mozziyar - - 2009
Myocardial contractility, the intrinsic ability of the heart muscle to produce force, has been difficult to quantify non-invasively. Pre-ejection-period (PEP), the time the ventricles spend in isovolumetric contraction, is widely accepted as a way to measure contractility. This work presents a way by which the ballistocardiogram - a readily accessible ...
Black Adam - - 2009
Intracellular regulation of myocardial Ca(2+) has long been of interest to physiologists. The force-interval relationship provides a phenomenological approach that permits insight into aspects of calcium regulation. The response to an extrasystole is a potentiation in contractile force and the recovery in contractile force is described by the recirculation fraction ...
Nguyen Mai-Dung - - 2009
Physiological heart development and cardiac function rely on the response of cardiomyocytes to mechanical stress signals during hemodynamic loading and unloading. These stresses manifest themselves via changes in cell structure, contractile function and gene expression. Disruption of this well balanced stress-sensing machinery due to various pathological conditions results in contractile ...
Quaile Michael P - - 2009
Urotensin-II (U-II) is an endogenous peptide upregulated in failing hearts. To date, insights into the myocardial actions of U-II have been obscured by its potent vasoconstrictor effects and interspecies differences in physiological responses to U-II. We examined the direct effects of exogenous U-II on in vitro contractility in nonfailing and ...
Folino Antonio Franco - - 2010
Previous studies proposed as one of the main mechanisms involved in neurally mediated syncope, the stimulation of ventricular mechanoreceptors as the final trigger for vagal discharge. This study aimed to verify the presence of a sympathetic driven increase of cardiac contractility before vasovagal syncope. We studied 23 patients with recurrent ...
Zhang X-J - - 2009
BACKGROUND: Several studies have demonstrated the inhibitory effect of propofol on diaphragmatic contractility in laboratory animals, but there have been few studies in humans. We have investigated the effect of a single bolus injection of propofol on twitch diaphragmatic pressure (TwPdi) evoked by cervical supramaximal magnetic stimulation, and its impact ...
Ramirez-Correa Genaro A - - 2008
In addition to O-phosphorylation, O-linked modifications of serine and threonine by beta-N-acetyl-D-glucosamine (GlcNAc) may regulate muscle contractile function. This study assessed the potential role of O-GlcNAcylation in cardiac muscle contractile activation. To identify specific sites of O-GlcNAcylation in cardiac myofilament proteins, a recently developed methodology based on GalNAz-biotin labeling followed ...
Irvine Jennifer C - - 2008
Until recently, most of the biological effects of nitric oxide (NO) have been attributed to its uncharged state (NO*), yet NO can also exist in the reduced state as nitroxyl (HNO or NO(-)). Putatively generated from both NO synthase (NOS)-dependent and -independent sources, HNO is rapidly emerging as a novel ...
Barber Robert C - - 2008
Burn injury has been associated with systemic/compartmental inflammatory responses and myocardial dysfunction. We hypothesized that burn size correlates with the extent of cardiac inflammatory response/contractile dysfunction. Adult male Sprague-Dawley rats were divided to receive anesthesia, a 3-degree burn covering 20%, 30%, 40%, or 60% total body surface area (TBSA) plus ...
Abraham William T - - 2008
Cardiac contractility modulation (CCM) signals are nonexcitatory electrical signals delivered during the cardiac absolute refractory period that enhance the strength of cardiac muscular contraction. Prior research in experimental and human heart failure has shown that CCM signals normalize phosphorylation of key proteins and expression of genes coding for proteins involved ...
Eszlári E - - 2008
The aim of this study was to outline the consequences of a hypertonic saline-dextran-40 (HSD) infusion-induced peripheral flow stimulus on the ventricular function in closed-chest, pentobarbital-anesthetized dogs. We hypothesized that HSD-induced elevation in endothelin-1 (ET-1) and nitric oxide (NO) release can have a role in myocardial contractile responses; and that ...
Pinz Ilka - - 2008
TNFalpha is a cytokine wit pleiotropic functions in many organs. In the heart increased TNFalpha levels are not only associated with heart failure, but also, paradoxically, with protection from ischemic damage. To test whether the protective role of TNFalpha in the heart is concentration-dependent, we studied two mouse heart models ...
Ojha Shreesh K - - 2008
In present study, hydroalcoholic extract of C. mukul significantly improved the cardiac function and prevented myocardial ischemic impairment manifested in the form of increased heart rate, decreased arterial pressure, increased left ventricular end diastolic pressure, and altered myocardial contractility indices. C. mukul treatment additionally also produced a significant increase in ...
Heusch G - - 2008
The bradycardic agent ivabradine has proved to be of benefit in experimental models with the end points of ischaemic myocardial blood flow and contractile function, infarct size, post-infarct remodelling and atherosclerosis. The benefits to ischaemic myocardial blood flow and contractile function are strictly heart rate dependent; those on infarct size ...
Ren Jun - - 2008
Compromised heart function is regularly seen in patients with chronic alcohol ingestion and is often manifested as cardiomegaly, reduced myocardial contractility (with concomitant reductions in ejection fraction and stroke volume), myocardial fibrosis, enhanced risk of stroke and hypertension, and disruptions in the myofibrillary structure. A number of mechanisms including oxidative ...
Sonin Dmitry - - 2008
Evidence is accumulating to support the presence of P2X purinergic receptors in the heart. However, the biological role of this receptor remains to be defined. The objectives here were to determine the role of cardiac P2X receptors in modulating the progression of post-myocardial infarction ischemic heart failure and to investigate ...
Shiels Holly A - - 2008
The Frank-Starling law of the heart applies to all classes of vertebrates. It describes how stretch of cardiac muscle, up to an optimum length, increases contractility thereby linking cardiac ejection to cardiac filling. The cellular mechanisms underlying the Frank-Starling response include an increase in myofilament sensitivity for Ca2+, decreased myofilament ...
Kassiotis Christos - - 2008
Myocardial energy substrate metabolism entails a complex system of enzyme catalyzed reactions, in which the heart efficiently converts chemical to mechanical energy. The system is highly regulated and responsive to changes in workload as well as in substrate and hormone supply to the heart. Akin to the terms "contractile reserve" ...
Sedmera David D Institute of Animal Physiology and Genetics, Prague, Czech Republic. - - 2008
This article concerns the development of myocardial architecture--crucial for contractile performance of the heart and its conduction system, essential for generation and coordinated spread of electrical activity. Topics discussed include molecular determination of cardiac phenotype (contractile and conducting), remodeling of ventricular wall architecture and its blood supply, and relation of ...
Khairallah M - - 2008
We recently demonstrated early metabolic alterations in the dystrophin-deficient mdx heart that precede overt cardiomyopathy and may represent an early "subclinical" signature of a defective nitric oxide (NO)/cGMP pathway. In this study, we used genetic and pharmacological approaches to test the hypothesis that enhancing cGMP, downstream of NO formation, improves ...
Blagonravov M L - - 2008
Acute coronary failure was modeled in rabbits by ligation of the descending left coronary artery at the interface of its middle and lower thirds. The function and morphology of left-ventricular and right-ventricular myocardium were studied on days 1, 3, and 5 of the pathological process. It was found that left-ventricular ...
Bedosky, Kristen Marie
The incidence of cardiovascular disease has reached epidemic proportions in North America. Specifically, myocardial infarctions (MI) are a major contributor to heart failure which greatly influences morbidity and mortality rates in developed nations. In the post-MI heart, cardiac fibroblasts migrate to the damaged area, convert to myofibroblasts and contribute to ...
Gonzalez-Muñoz Carmen - - 2008
This study evaluates the inotropic responses to glucagon in electrically driven isolated left and right atria as well as in right ventricular strips of rat heart. For comparison, the contractile effects resulting from stimulating beta-adrenoceptors with isoprenaline in atrial and ventricular tissues were also obtained. Glucagon (0.01-1 microM) produces a ...
Durgan David J - - 2008
INTRODUCTION: The energetic demands imposed upon the heart vary dramatically over the course of the day. In the face of equally commanding oscillations in the neurohumoral mileu, the heart must respond both rapidly and appropriately to its diurnal environment, for the survival of the organism. A major response of the ...
Mansouri Seyed Mohammad-Taghi - - 2008
BACKGROUND: Selective phosphodiesterase (PDE3) inhibitors improve cardiac contractility and may use in congestive heart failure. However, their proarrhythmic potential is the most important side effect. METHODS: In this research, we evaluated the potential cardiotonic activity of six new synthesized selective PDE3 inhibitors (6-hydroxy-4-methylquinolin-2(1H)-one derivatives) using the spontaneously beating atria model. ...
Doenst Torsten - - 2008
It is the principal goal of cardiac surgeons to improve or reinstate contractile function with, through or after a surgical procedure on the heart. Uninterrupted contractile function of the heart is irrevocably linked to the uninterrupted supply of energy in the form of ATP. Thus, it would appear natural that ...
Pantos Constantinos - - 2008
Thyroid hormone has various effects on the cardiovascular system and its effects on cardiac contractility, heart rhythm and vascular function has long been recognized. However, new evidence is emerged on the importance of thyroid hormone in the response of the myocardium to ischaemic stress and cardiac remodelling following myocardial infarction. ...
Bray Molly S - - 2008
The heart is challenged by a plethora of extracellular stimuli over the course of a normal day, each of which distinctly influences myocardial contractile function. It is therefore not surprising that myocardial metabolism also oscillates in a time-of-day dependent manner. What is becoming increasingly apparent is that the heart exhibits ...
Sando Ian C - - 2008
Tumor necrosis factor-alpha (TNF-alpha) plays a critical role in myocardial dysfunction following acute injury. It is unknown, however, if a gender-specific response to TNF infusion exists in isolated rat hearts. Elucidating such mechanisms is important to understanding the myocardial gender differences during acute injury. We hypothesize that females will exhibit ...
Lian F - - 2008
This study was designed to evaluate the long-term effect of endothelial progenitor cell (EPC) implantation in acute myocardial infarction in Sprague-Dawley rats after ligation of the left anterior descending coronary artery. Autologous EPCs from peripheral blood were purified and implanted into an acute myocardial infarct site. Specimens and muscle strip ...
Lee Marlon A - - 2008
Acute injury-induced cardiac contractile dysfunction occurs even in young and otherwise healthy individuals after major injuries, and significantly contributes to morbidity and mortality in patients with pre-existent cardiac diseases as well as in patients who develop multiple organ dysfunction syndrome. Recent studies indicate that post-injury acute cardiac failure is the ...
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