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Results 301 - 350 of 504
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Davis Stephen D - - 2002
Progressive diebacks of outer canopy branchlets of Ceanothus crassifolius were repeatedly observed after rainless periods up to 9 mo in duration in the Santa Monica Mountains of southern California. Mean xylem pressures of branchlets near the end of drought were as low as -11.2 MPa (N = 22) with a ...
Knott Adam - - 2002
Contractility of the myocardium is altered in end-stage heart failure. We investigated whether this was related to functional changes in troponin. We isolated troponin from 1 g samples of end-stage failing, non-failing and foetal human heart and studied its regulation of actin-tropomyosin movement over immobilised HMM by in vitro motility ...
Young M J - - 2001
The present study explores the possibility of local de novo aldosterone production in normal and failing hearts (human and mouse) and the regulation of such putative cardiac steroidogenesis. Total RNA was isolated from human tissue from failing hearts taken at the time of cardiac transplantation, from normal hearts obtained at ...
Dschietzig T - - 2001
Human congestive heart failure is characterized by complex neurohumoral activation associated with the up-regulation of vasoconstricting and salt-retaining mediators and the compensatory rise of counter-regulatory hormones. In the present study, we provide the first evidence that relaxin (RLX), known as a pregnancy hormone, represents a potential compensatory mediator in human ...
Bodor N - - 2001
A novel tryptamine analog, 1-methyl-3-[N-(3-indolyl)ethyl]carbamoyl-1,4-dihydropyridine (T-CDS) was synthesized and converted into a stable, solid complex with 2-hydroxypropyl-beta-cyclodextrin. An aqueous solution of the complex was given intravenously to dogs and the concentration of T-CDS and its corresponding quaternary (T-Q+) forms were monitored in the blood for 50 min. The effect of ...
Lemanski L F - - 2001
The Mexican axolotl (Ambystoma mexicanum) provides an excellent model for studying heart development since it carries a cardiac lethal mutation in gene c that results in failure of contraction of mutant embryonic myocardium. In cardiac mutant axolotls (c/c) the hearts do not beat, apparently because of an absence of organized ...
Breckenridge R A - - 2001
The heart develops from a linear tubular precursor, which loops to the right and undergoes terminal differentiation to form the multichambered heart. Heart looping is the earliest manifestation of left-right asymmetry and determines the eventual heart situs. The signalling processes that impart laterality to the unlooped heart tube and thus ...
Wang X Z - - 2001
A hierarchical self-organizing map (SOM) has been developed for automatic detection and classification of abnormalities for artificial hearts. The hierarchical SOM has been applied to the monitoring and analysis of an aortic pressure (AoP) signal measured from an adult goat equipped with a total artificial heart. The architecture of the ...
Chin A J - - 2000
A fundamental problem in developmental biology is how left-right (LR) asymmetry is generated, both on the whole organism level and at the level of an individual organ or structure. To investigate the relationship of organ sidedness to organ chirality, we examined 12 zebrafish mutants for initial heart tube position and ...
Pauza D H - - 2000
Concomitant with the development of surgical treatment of cardiac arrythmias and management of myocardial ischemia, there is renewed interest in morphology of the intrinsic cardiac nervous system. In this study, we analyze the topography and structure of the human epicardiac neural plexus (ENP) as a system of seven ganglionated subplexuses. ...
Love M P - - 2000
OBJECTIVE: The relative importance of ETA and ETB receptors in mediating the constrictor effects of endogenous endothelin-1 in patients with chronic heart failure is not known. The primary purpose of this study was to compare the acute effects of selective ETA and ETB receptor antagonists in vivo in healthy subjects ...
Barnes J A - - 2000
This study investigates the distribution and heart levels of glucose regulated protein (GRP) 78 during normal development and in response to hypoglycemia in the mouse. Results demonstrate that GRP78 is strongly expressed with in the heart, neural tube, gut endoderm, somites, and surface ectoderm of mouse embryos during early organogenesis, ...
Crehan C M - - 2000
The effects of salt level and high pressure processing on cook loss, emulsion stability, colour, textural and sensory characteristics of frankfurters were investigated. Two salt levels (1.5 and 2.5%) and two pressure treatments (150 and 300 MPa) were examined. For each batch a control was set up which was non-pressure ...
Mutter T - - 2000
Treatment of rats with thyroxine has been shown to elevate the biosynthesis and content of cardiolipin in the heart [Cao, Cheng, Angel and Hatch (1995) Biochim. Biophys. Acta 1256, 241-244]. Treatment with thyroxine resulted in a 1.8-fold increase (P<0.025) in [1-(14)C]linoleate and a 1.7-fold increase (P<0.025) in [1-(14)C]oleate incorporated into ...
Gold J - - 2000
The use of phosphodiesterase inhibitors such as milrinone in the treatment of severe heart failure is frequently restricted because they cause vasodilation and hypotension. In patients with decompensated heart failure with hypotension after treatment with milrinone, low doses of vasopressin restored blood pressure without inhibiting the inotropic effect of milrinone.
Litster A L - - 2000
OBJECTIVE: To determine absolute and relative heart size in clinically normal cats by correlating heart size and selected skeletal structures. DESIGN: Prospective radiographic study. ANIMALS: 100 cats that did not have thoracic radiographic abnormalities. PROCEDURE: Standardized measurements of the long and short axes of the heart, midthoracic vertebrae, and other ...
Koncan D - - 2000
The porcine heart was used as a model for studying the thermal changes in myocardium at cooling and re-warming during open heart surgery. A section of the heart septum was excised and tissue was cut into two similar square slices. The same shape of the tissue, cut from the surface ...
Kozłowski D - - 2000
The tendon of Todaro, found in the right atrium of the heart, has considerable clinical importance in the fields of both cardiac surgery and invasive cardiology. The goal of this study was to examine the occurrence and degree of development of the tendon of Todaro in humans. Research was conducted ...
Hillier C - - 1999
The physiological response to a chronically failing heart is the implementation of compensatory mechanisms intended to support blood pressure. These mechanisms, which are not fully understood, increase peripheral vascular tone, thus increasing the strain on the weakened myocardium. This study investigated the structure and function of small arteries from heart ...
Suddaby E C - - 1999
The embryological development of the heart is an awesome and complex process. The heart is formed from groups of cells that coalesce into sheets of tissue. These sheets fuse to form a tube that grows into the atria and ventricles. The twists and turns of the developing heart tissue and ...
Grobéty M - - 1999
The mechanisms regulating remodeling of the heart are not well understood and only rarely investigated for pacing. We therefore developed a model based on the well-established chick embryo heart preparation. Hamburger Hamilton 21 stage Leghorn chick embryos were used. Access to the heart was obtained after having dissected the shell ...
Murakawa Y - - 1999
To clarify whether peak-to-peak interval of the fibrillation wave (VF interval) during VF is an independent indicator of defibrillation efficacy, we measured the transcardiac DFT, VF intervals of the surface and local ECGs (lead II and the right ventricle), and the ERP in 82 open-chest dogs. Both VF intervals showed ...
McGovern R H - - 1999
Ascites syndrome in broiler chickens is defined as a condition associated with pulmonary hypertension leading to right heart failure, increased central venous pressure, passive congestion of the liver, and accumulations of serous fluids in body cavities. The syndrome is currently seen in fast-growing broiler chickens associated with an increase in ...
Sakai T - - 1998
We used optical methods to examine the spatial gradient of intrinsic rhythmicity in early-stage multiple-heart chick embryos. The latter were induced experimentally in whole-embryo culture. The embryos were cut microsurgically through the tissue of the anterior intestinal portal at the 5- to early 7-somite developmental stage. Spontaneous electrical activity in ...
Freeman L M - - 1998
Alterations in body composition and nutritional status are common in humans with heart failure and are related, in part, to increases in cytokine concentrations. Cytokines have not been studied previously in dogs with naturally occurring cardiac disease nor has fish oil administration been used in this population to decrease cytokine ...
Wu T J - - 1998
OBJECTIVES: We sought to evaluate the characteristics of wave fronts during ventricular fibrillation (VF) in human hearts with dilated cardiomyopathy (DCM) and to determine the role of increased fibrosis in the generation of reentry during VF. BACKGROUND: The role of increased fibrosis in reentry formation during human VF is unclear. ...
Sueshiro M - - 1998
In the process of developing a completely implantable total artificial heart system, we have made an eccentric roller type total artificial heart and evaluated it by means of a mock circulatory system and by an acute animal experiment. The actuator of the artificial heart consists of 2 cylindrical drum type ...
Huang G Y - - 1998
Connexin 43 (Cx43) knockout mice and transgenic mice (CMV43) overexpressing the Cx43 gap junction gene exhibit heart defects involving the conotruncus and right ventricle. Based on the heart phenotype and Cx43 gene and transgene expression pattern, we previously proposed that the heart defects may reflect a role for gap junctions ...
Hajjar R J - - 1998
We used a catheter-based technique to achieve generalized cardiac gene transfer in vivo and to alter cardiac function by overexpressing phospholamban (PL) which regulates the activity of the sarcoplasmic reticulum Ca2+ ATPase (SERCA2a). By using this approach, rat hearts were transduced in vivo with 5 x 10(9) pfu of recombinant ...
Pietersen H G - - 1998
Glutamate infusion has been shown to exert beneficial hemodynamic effects in patients with heart failure after cardiac surgery. To elucidate the underlying mechanism we studied the possibility that glutamate is a Krebs-cycle precursor in the human heart. Therefore [1-13C]glutamate was infused in order to show production of 13CO2 by the ...
Knowlton A A - - 1998
BACKGROUND: Heat shock proteins (hsp) constitute an endogenous stress response that protects cells from injury. Most work on these important proteins has focused on the immediate response to acute stress in cell culture systems and mammalian models of heart disease. Little is known about the expression of the hsps in ...
Holly R G - - 1998
Physical conditioning induces numerous cardiovascular adaptations, including vagotonia and increased cardiac volume and mass. These adaptations characterise the 'athletic heart' and account for most of the normal variants in the athlete's electrocardiogram. Common alterations associated with vagotonia include sinus bradycardia, sinus arrhythmia, junctional escape beats, first degree atrioventricular block and ...
Badeer H S - - 1998
It has been observed that climbing arboreal snakes have hearts closer to the head than nonclimbing terrestrial or aquatic snakes. The closeness to the head is said to minimize the work of the heart in pumping blood to the head. However, there is ample evidence that the gravitational pressure in ...
Neuburger M - - 1998
In the present study we examined light-microscopically the nuclei of 16 hearts (7 normal hearts, 7 hearts with hypertrophy and 2 hearts with atrophy) for the size, number and morphology of their nucleoli. The size of the nucleoli, defined as the total area of all nucleoli per nucleus, was an ...
Aydinlioğlu A - - 1998
The normally developing cardiovascular system of the chicken resembles that of the human. The purpose of the present study is to investigate some macroscopic and microscopic similarities between the chick and the human heart. For this study 20 adult and 10 newborn Broiler chickens were used. The heart and great ...
Canny M - - 1997
A test was attempted of the assumption that, when a leaf is cut, the xylem still contains water under tension beyond the first vessel cross walls. This assumption enabled Scholander to argue that the balance pressure in his pressure chamber measured the tension in water columns in the vessels before ...
Acierno R - - 1997
Channichthyid icefishes of Antarctica are unique among adult vertebrates. All icefish species lack hemoglobin and red blood cells in their circulating blood. All icefishes examined to date also lack the intracellular oxygen-binding protein myoglobin (Mb) in their oxidative skeletal muscles. However, some icefish species do express Mb in their heart ...
Thivierge M - - 1997
Rotating fibers in the heart lead to a myocardium of inhomogeneous anisotropic conductivity. Besides affecting the activation isochrones, this anisotropy modifies the equivalent dipoles used in calculating extracardiac potentials, rendering them oblique rather than normal to the activation wavefront due to an added axial dipole component oriented along the fibers. ...
Dalecki D - - 1997
Earlier studies have shown that a single, millisecond duration pulse of ultrasound delivered to the frog heart in vivo during systole can produce a reduction in the developed aortic pressure, while a pulse delivered during diastole can produce a premature ventricular contraction. The threshold for these effects is 5-10 MPa ...
Anderson P A - - 1996
The perspective from which the developing heart is viewed can lead to differing conclusions about the effects of development on cardiac function. The hearts of the embryo, fetus and adult, viewed from a global perspective, sustain the circulation through the same basic mechanisms of developing pressure and ejecting blood. The ...
Louzada P R PR - - 1996
Effects of hydrostatic pressure on the fluorescence emission of L-tryptophan, N-acetyl-L-trytophanamide and indole were investigated. An increase in pressure ranging from 1 bar to 2.4 kbar results in reversible red-shifts of the emission of the three fluorophores. The pressure-induced redshift amounts to about 170 cm(-1) at 2.4 kbar, and appears ...
Barragán J M - - 1996
This study was designed to determine the interactions of peptide exendin-(9-39) with the effect of glucagon-like peptide-1-(7-36) (GLP-1 (7-36)) amide and of exendin-4 on arterial blood pressure and heart rate in the rat. Both GLP-1 (7-36) amide and exendin-4 produced a dose-dependent increase in systolic, diastolic and mean arterial blood ...
Ferrari R - - 1996
Congestive heart failure is a clinical syndrome in which the capacity of the heart to maintain cardiac output is impaired. As a consequence, blood pressure is threatened and endocrine and paracrine mechanisms are activated to preserve circulatory homeostasis and to maintain blood pressure. At terminal stages, a complex multiorgan syndrome ...
Linck B - - 1996
1. The effect of the phosphatase inhibitor, cantharidin (3-300 microM) on force of contraction was studied in isolated electrically driven right ventricular trabeculae carneae from human myocardium. 2. The positive inotropic effect of cantharidin started at a concentration of 100 microM with a positive inotropic effect to 199% and to ...
Nimon A J - - 1996
A technique for the noninvasive measurement of heart rate in incubating penguins is described and evaluated. The technique uses an artificial egg fitted with an infrared sensor. Placing the egg in the nest causes minimal disturbance to the resident penguin; this penguin is then paint-marked so that subsequent measurements may ...
Biggers V - - 1996
Do belching, chills, fatigue, and pressure just above the ribs sound like the symptoms of a heart attack? To most patients, they probably don't. However, research is indicating that a victim's actual symptoms often do not match his or her expectations of what a heart attack should feel like. As ...
Yamamoto S - - 1996
Intercellular dehiscence is a common cardiocytic response to pathological conditions. However, little consideration has been given to the possibility of new intercellular junctions developing between cardiocytes within developed myocardium. To examine this possibility as it may relate to useful compensation for hemodynamic overloads, changes in cardiocytic connection were evaluated by ...
Kocijancic S - - 1996
The left ventricular pressure (LVP) and ECG signals that appear during and after ischaemia tend to be very irregular (fibrillation, arrhythmia). Computer based data acquisition system, that we developed to support experiments on isolated Langendorff's rat heart, enabled the usage of methods derived from non-linear dynamics. To classify the irregularity ...
Llobel F - - 1996
We have examined the effects of morphine in auricular myocardium from non-failing and failing human hearts. In both preparations morphine induced inhibition. These responses were not antagonized by naloxone. Comparison of mean IC30 values obtained in non-failing (3.9 (SEM 0.2) x 10(-8) mol litre-1) and failing (5010 (200) x 10(-8) ...
Schönekess B O - - 1995
Propionyl L-carnitine (PLC) is a naturally occurring derivative of L-carnitine that can improve hemodynamic function of hypertrophied rat hearts. The mechanism(s) responsible for the beneficial effects of PLC is not known, although improvement of myocardial energy metabolism has been suggested. In this study, we determined the effect of PLC on ...
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