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Results 401 - 450 of 542
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Xie J T - - 1993
Monophasic action potentials (MAPs) are a measure of electrical activity of local myocardial cells recorded from the epicardial or endocardial surfaces of the beating heart, in vivo, using a positive pressure-contact electrode or electrode catheter. The MAP technique is a reliable and safe method for studying and detecting the cardiac ...
Segel L D - - 1993
These experiments tested the hypothesis that addition of pyruvate to a preservation medium would improve postpreservation cardiac function as quantified in an isolated working heart model after heterotopic transplantation. Four groups of rabbit hearts were studied (n = 5 per group): fresh controls, fresh hearts perfused as isolated working hearts; ...
McKean T A - - 1993
The purpose of this study was to compare the responses of isolated hearts of the diving muskrat with the nondividing guinea pig (GP) to determine the contribution of adenosine (ADO) to the profound bradycardia that was seen in isolated muskrat hearts during exposure to hypoxia. Muskrat hearts were more sensitive ...
Carver W - - 1993
Significant physiological changes occur in the heart following birth including increased arterial blood pressure and heart rate. Concurrently, biochemical and structural alterations are evident in the neonatal heart in response to these dynamic physiological properties. Prominent among these is the elaborate development of the cardiac extracellular matrix, composed primarily of ...
Goldstein L J - - 1993
This paper details a versatile and easy to use electrical network model of the heart in which the user can control the heart rate, blood pressure, end-diastolic left ventricular pressure, and proportion of time spent in systole. Several dysrhythmias and cardiac diseases can be simulated, including asystole, second and third ...
Frunchak Y N - - 1993
The early heart anlagen of Xenopus laevis embryos were exposed to purified embryonic galactoside-binding lectin or its potent hapten inhibitor thiodigalactoside (TDG). Heart development was then studied using a variety of microscopical techniques. Conotruncal morphology and positioning with respect to the ventricle are altered in treated animals. In 34% of ...
Laflamme A K - - 1992
Clentiazem, 8-chloro diltiazem, is a calcium channel blocker currently undergoing evaluation for the treatment of stable angina and hypertension. As patients with ischaemic disorders often present some degree of heart failure, the aim of this study was to investigate the effect of congestive heart failure on clentiazem (200 micrograms kg-1, ...
Alpert N R - - 1992
A myothermal/mechanical analysis on non-failing and failing human hearts and normal and pressure overloaded rabbit hearts is reported. Heat production is partitioned into tension-dependent and tension-independent components together with force measurements to provide information about calcium and cross-bridge cycling. In the non-failing human heart the cross-bridge force-time integral is 0.51 ...
Alvarez L - - 1992
The effects of fentanyl at a dose of 100 micrograms.kg-1 on cardiac automaticity, refractoriness and conduction have been studied in a model of heterotopic heart transplantation which combines a denervated heart (donor) and a non-denervated heart (recipient) in each of 20 dogs employed. Once the surgical procedure had been completed, ...
Tsao C Y - - 1992
The majority of patients with Friedreich ataxia present with gait ataxia. Congestive heart failure usually is a terminal event. We report a 9-year-old boy who developed congestive heart failure and thrombus formation in the left ventricle at age 5 years and then progressive ataxia as well as other features of ...
Kageyama M - - 1992
We investigated the effects of semotiadil (SD-3211), a novel calcium antagonist, on blood pressure and the atrioventricular (AV) conduction time and functional refractory period (FRP) of the AV conduction system (AV conductivity) in anesthetized open-chest dogs. The heart was electrically stimulated at a constant rate. In dogs with an intact ...
Murtagh J - - 1992
Palpitations are an unpleasant awareness of beating of the heart. By definition, the condition does not always imply 'racing' of the heart but encompasses any sensation in the chest such as 'pounding', 'flopping', 'skipping', 'jumping', 'thumping' or 'fluttering' of the heart. The problem requires careful attention and reassurance because heart ...
Banker M C - - 1992
We compared the cryoprotective ability of glycerol and polyethylene glycol (PEG) during freezing. Isolated rat hearts were flushed with one of three cardioplegic solutions (CP-14, CP-15, and CP-16), frozen at -1.4 degrees C, and reperfused after thawing to assess function. After 3 h freezing, cardiac output (CO) in CP-14-flushed hearts ...
Easton H - - 1992
Grafts of mesoderm taken from the precardiac region of quail embryos of stages 5-7 were inserted into the precardiac mesoderm of chick embryos of stages 5-7. The experiments were of four types and were code named to indicate the origin and the destination of the graft. QACP: tissue from the ...
Green L S - - 1991
BACKGROUND: Epicardial excitation sequences, recovery sequences, and potential distributions are recorded from patients during surgery and from animals in the research laboratory for a variety of purposes. During such recordings, a portion of the cardiac surface is exposed to air, and the remainder of the epicardial surface variably is in ...
Johansson B W - - 1991
During hibernation the animals decrease their body temperature down to a few degrees above 0 degree C. This means that when entering into and arousing from hibernation their body temperature passes the critical level of 20 degrees C, a temperature region where nonhibernating mammals develop circulatory arrest, usually ventricular fibrillation ...
Flynn M E - - 1991
Chick embryos, during stages 14 to 25, undergo an arching of the hindbrain and cervical neural tube that is termed cervical flexure. We have found that if the truncus arteriosus is severed during stage 12-13, the embryos survive for more than 24 h and do not show cervical flexure. The ...
Itasaki N - - 1991
The role of actin bundles on the heart looping of chick embryos was examined by using cytochalasin B, which binds to the barbed end of actin filaments and inhibits association of the subunits. It was applied to embryos cultured according to New's method. Looping did not occur when cytochalasin B ...
Opie L H - - 1990
The compensatory mechanisms that develop in response to heart failure have been well defined. In this review, it is argued that each compensatory mechanism leads to overcompensation and that there is no way to distinguish between the beneficial aspects of the former and the harmful effects of the latter. Therapeutic ...
Berrebi-Bertrand I - - 1990
The contribution of the heterogeneous digitalis receptors to the inotropic effect of ouabain was studied in hypertrophied rat hearts (aortic stenosis) by using isolated Langendorff heart preparations. Development and washout of the biological effects as well as the dose/response curves revealed two inotropic components of high and low drug sensitivity. ...
Wafae N - - 1990
This work was carried out in 50 hearts of human adult cadavers of both sexes, whose obit causes were not related to diseases which could have been directly involved with the heart. The septal trabecula carnea was identified in 45 hearts (90%), with origin in the superior portion of the ...
Krotje L J - - 1990
Intracardiac rhabdomyosarcoma was diagnosed in a 14-month-old Golden Retriever referred for evaluation of syncope. The dog was weak, with irregular heart rate, pulse deficit, heart murmur, and hepatomegaly. Thoracic radiography revealed generalized cardiomegaly, and electrocardiography revealed sinus rhythm with multiform ventricular premature complexes and intermittent ventricular tachycardia. Two-dimensional echocardiography revealed ...
Sater A K - - 1990
We have examined the spatial restriction of heart-forming potency in Xenopus laevis embryos, using an assay system in which explants or explant recombinates are cultured in hanging drops and scored for the formation of a beating heart. At the end of neurulation at stage 20, the heart morphogenetic field, i.e., ...
van Nie C J - - 1990
A macroscopic description of four hearts showing three arterial ostia in the base of the pig's heart was carried out. Portions of the vascular walls were histologically examined in three hearts. All hearts belong to the Tetralogy of Fallot group. Spitzer's hypothesis concerning the phylogenetic development of the mammalian heart ...
Nakajo M - - 1990
Variations in heart intensity in the 30 min and 4 hr chest images of the radiolabelled lipophilic amine, N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) were observed in 130 patients with lung diseases, aged 23 to 85 yrs. The heart intensity had a significant positive linear correlation with age (r = 0.43 at 30 min, ...
Buser P T - - 1990
There is controversy as to whether potent inotropic agents are beneficial or detrimental in moderate to severe heart failure. Accordingly, we studied the effects of amrinone, amrinone plus dobutamine, and dobutamine alone on mechanical performance, myocardial oxygen consumption, and high energy phosphate metabolism in different stages of congestive heart failure ...
Sater A K - - 1990
We have examined the tissue interactions responsible for the expression of heart-forming potency during gastrulation. By comparing the specification of different regions of the marginal zone, we show that heart-forming potency is expressed only in explants containing both the dorsal lip of the blastopore and deep mesoderm between 30 degrees ...
Tucker D C - - 1990
Culture of embryonic heart in the anterior eye chamber allows neurohumoral and genetic controls of cardiac development to be separated from the influence of hemodynamic load. Hearts from 12-day gestation rat embryos grafted into the anterior eye chamber of an adult host rat attach to the iris and become vascularized ...
Shen P S - - 1989
Recessive mutant gene c for "cardiac nonfunction" in axolotls results in an absence of normal heart contractions in affected embryos due to a failure of myofibril formation. In the present study, the intermediate filament protein, desmin, is compared in developing normal and mutant hearts by means of two-dimensional gel electrophoresis, ...
Mabuchi K - - 1989
By fixing the function of one ventricle, a total right heart bypass model can clarify the function and regulatory mechanism of the natural heart, and the etiology of abnormal hemodynamics in TAH animals such as increased CVP blood pressure and hepatic congestion. The pulmonary artery of a right heart bypass ...
Sater A K - - 1989
The establishment of heart mesoderm during Xenopus development has been examined using an assay for heart differentiation in explants and explant combinations in culture. Previous studies using urodele embryos have shown that the heart mesoderm is induced by the prospective pharyngeal endoderm during neurula and postneurula stages. In this study, ...
Nelson C V - - 1989
We have measured magnitude and location of heart dipole moment during QRS in 46 New Zealand white rabbits. The spatial magnitude curve had one to three peaks. Mean values were M1 = 80 +/- 10 microA-cm (N = 5) pointing to right anterior and caudal, M2 = 260 +/- 15 ...
Mandarim-de-Lacerda C A - - 1989
The heart of 3 human embryos at 17 mm C-R (stade 19) was studied by means of light microscopy and quantitative methods. The serial sections of the embryos were projected for the measurement of the cardiac diameters and cardiac profile areas (point-counting planimetry). The calculated heart volume for each embryo ...
Satoh M - - 1988
The effect of pretreatment of mice with heavy metals: Zn, Cu, Bi, Co, Cd or Hg, against lethal and cardiac toxicity of adriamycin (ADR) was investigated. The lethal toxicity of ADR was significantly reduced by pre-administration of these metals except for Cu. The levels of both malondialdehyde and conjugated dienes, ...
Anderson R H - - 1988
In the past, it has often been the case that congenital malformations have been categorized in terms of their presumed embryologic development. The knowledge of development, however, has itself often been derived from studies of the normal heart during its development coupled with inferences drawn from the morphology of the ...
Wolkowicz J - - 1988
An Inuit family from Cape Dorset, Northwest Territories is described; six had documented complete heart block, one high grade atrioventricular block, one bi- or trifascicular block and all suffered syncope. One other member received a pacemaker for unknown reasons. Two of three middle-aged relatives had minor conduction abnormalities. All younger ...
Melinek R - - 1988
The heart of the axolotl Ambystoma mexicanum was studied with histochemical methods to determine the distribution of neurons containing acetylcholine esterase, catecholamines and 5-hydroxytryptamine. The cardiac ganglion is made up of cholinergic nerve fibers and somata, and of catecholaminergic fibers. Small intensely fluorescent cells were found along blood vessels in ...
Bojenko S - - 1988
A case of a 36-year-old pilot with a left sided accessory pathway (Kent bundle) is presented. The electrophysiological study revealed spontaneous changes in atrioventricular conduction in both the accessory and physiological pathways, lack of retrograde conduction via accessory pathway, and constant ventriculoatrial block in the atrioventricular node during the pacing ...
Satoh K - - 1988
The efficacy of MCI-154, a new pyridazinone cardiotonic agent, in improving heart failure was assessed in dog heart-lung preparations in which cardiac function had been severely depressed by pentobarbital. MCI-154 in doses of 10-100 micrograms improved the cardiac function curve and restored it to the control level at 100 micrograms. ...
Magaribuchi T - - 1988
Two rat hearts were perfused in series by a modified Loewi's method. The recipient heart was perfused with the perfusate collected from the donor heart. 1. After perfusion with 3H-isoprenaline in the presence of tropolone, an inhibitor of catechol-O-methyltransferase, the donor heart was washed out with amine-free medium containing tropolone ...
Jakab G - - 1988
Phosphorylation of phospholipids was studied in Langendorff perfused guinea pig hearts subjected to beta-adrenergic stimulation. Hearts were perfused with Krebs-Henseleit buffer containing [32P]Pi and freeze-clamped in a control condition or at the peak of the inotropic response to isoprenaline. 32P incorporation into total phospholipids, individual phospholipids and polyphosphoinositides was analysed ...
Runnalls M E - - 1987
An Ag-AgCl electrode for recording monophasic action potentials by pressure contact is described. The electrode is mounted in a hand-held support designed for epicardial recordings during open-heart surgery from both the anterior and lateral walls of the left ventricle with minimal displacement of the heart. The support allows the electrode ...
Barry A C - - 1987
To compare the function of old and young hearts contracting under identical conditions, isolated hearts of young and old C57BL/6J mice were perfused using a Langendorff preparation. During a 3-min period of anoxia some hearts showed a decrease in systolic pressure, while other hearts developed contracture. The incidence and magnitude ...
Slinker B K - - 1987
Recently proposed concepts of pericardial surface pressure, as opposed to liquid pressure, have advanced our understanding of the relationship between pericardial and heart chamber pressures. However, the subsequent suggestion that right heart intracavitary pressure equals, or nearly equals, pericardial surface pressure is not strictly consistent with the physiology of pericardial ...
Tanaka M - - 1987
To define the pathogenetic role of myocardial fiber disarray in the progression of cardiac fibrosis, the percent area of fibrosis in tissue with disarray was compared with that in tissue without disarray. Thirty autopsied hearts, 10 from patients with hypertrophic cardiomyopathy, 10 from patients with hypertension and 10 from normal ...
Nilsson G - - 1987
The relation between distribution patterns of ventricular premature complexes (VPCs) and heart rate in Holter recordings abundant in VPCs was analyzed using computer-assisted determination of the number of interectopic sinus beats at different heart rates. Within the complete 24-hour heart rate spectrum, zones were demonstrated that were characterized by manifest ...
Hill K E - - 1987
Selenium deficiency causes a fall in rat cardiac glutathione peroxidase activity. As a consequence, isolated perfused selenium-deficient heart does not release increased amounts of GSSG when hydroperoxide is infused. However, the total amount of glutathione measured as intracellular GSH, intracellular GSSG and GSSG released from the heart when hydroperoxide is ...
Bisaillon A - - 1987
The heart of the beluga whale (Delphinapterus leucas) is described from the dissection of seven specimens. As in most whales the heart is characterized by a transverse broadness and a flatness of the ventricles from one surface to the other and by an apex formed by both ventricles. Heart size ...
Dunaway G A - - 1986
The nature of 6-phosphofructo-1-kinase isozyme pools in fetal, neonatal, young adult (3 months), and aged (30 months) rat hearts was studied using chromatographic and immunological techniques. Furthermore, the changing subunit composition of each isozyme pool was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis on 6% slab gels and by immunoblotting ...
Fuller R W - - 1986
A single dose of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) in mice caused 75-87% depletion of heart norepinephrine (NE) concentration 24 hrs later. MPP+ (1-methyl-4-phenylpyridinium) caused similar depletion of heart NE. The effect of MPTP was not blocked by pretreatment with deprenyl, an inhibitor of type B monoamine oxidase (MAO-B). Also, deprenyl pretreatment did ...
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