Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Heart development”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,081 records · Page 60Linked to original sources
PubMed1982

Use of a multichannel analysis profile for the assessment of risk of developing coronary heart disease.

The use of serum total cholesterol: high density lipoprotein cholesterol (TC:HDL-C) is well-established. Because HDL-C measurements are expensive, and cholesterol is part of the multichannel analysis profile, the author attempted to determine whether other parameters which are part of this profile could be useful indicators of the TC:HDL-C ratio. Based on an inverse correlation obtained in healthy men (42-59 years of age) between HDL-C and fasting plasma glucose (r = 0.40, P less than 0.001), triglycerides (r = 0.51, P less than 0.001), and uric acid (r = 0.29, P less than 0.01), a GUT (glucose, uric acid, triglyceride) score was calculated and correlated with the TC:HDL-C ratio (r = 0.86, P less than 0.001). In over 90% of cases the GUT score was able to predict whether an individual was likely to have a TC:HDL-C ratio of less than 4.5 or greater than 4.5. Thus, the GUT score is a useful indicator for an individual who is likely to require a lipid profile which includes HDL-C measurement.

Adult↗
PubMed1993

Cardiac dysfunction and development of heart failure.

A major consequence of chronic cardiac dysfunction is chronic overload of contractile myocardium. Various aetiologies, in reaction to this, may induce compensatory mechanisms consisting of excentric (dilatation) and concentric hypertrophy. Chronic left ventricular dysfunction is caused most frequently by myocardial infarction. Left ventricular dilatation and hypertrophy occurs in patients with extensive infarction. Dilatation may at first be compensatory, restoring stroke volume within 4 weeks of the infarct. However, as dilatation progresses, left ventricular ejection fraction and stroke volume deteriorate during exercise and at rest, and finally pulmonary capillary wedge pressure increases and patients become symptomatic 1.5-3 years after the infarct. Major determinants of progressive left ventricular dilatation and deterioration of haemodynamics are a depressed left ventricular ejection fraction, angiographically determined infarct size, stroke volume early (4 days) after myocardial infarction, infarct location (anterior/inferior) and the grade (TIMI) of perfusion of the infarct-associated coronary artery. Chronic loading and unloading may accelerate or decelerate this process. Efficiency and energy reserve (phosphocreatine) of the dilated ventricles is reduced. Further intrinsic changes in surviving myocardium include morphological and functional disturbance of coronary microcirculation.

Cardiomegaly↗
PubMed1998

Genetic risk factors in the development of heart disease: familial hypercholesterolemia and hyperhomocysteinemia.

Cardiovascular disease continues to be the leading cause of death in the United States. Several risk factors for heart disease are genetically based. Two of these risk factors are familial hypercholesterolemia and hyperhomocysteinemia. Effective and relatively inexpensive treatments have been established for these risk factors. This article reviews the genetic basis for familial hypercholesterolemia and hyperhomocysteinemia, presents strategies for diagnosis and treatment, and discusses implications for nursing practice.

Genetic Testing↗
PubMed1999

Beta2-adrenergic receptor overexpression in the developing mouse heart: evidence for targeted modulation of ion channels.

1. We studied the effect of overexpression of the beta2-adrenergic receptor (beta2-AR) in the heart on ion channel currents in single cells isolated from hearts of fetal and neonatal transgenic and wild-type mice. The beta2-AR transgene construct was under the control of the murine alpha-myosin heavy chain (alpha-MHC) promoter, and ion channel activity was measured at distinct developmental stages using whole-cell and perforated patch clamp techniques. 2. We found no change in L-type Ca2+ channel current (ICa) density in early embryonic stages (E11-13) of beta2-AR transgenic positive (TG+) mice, but significant increases in ICa density in intermediate (E14-16, 152 %) and late (E17-19, 173.7 %) fetal and neonatal (1 day post partum, 161 %) TG+ compared with transgenic negative (TG-) mice. This increase in ICa was accompanied by a negative shift in the peak of the current-voltage relationship in TG+ mice. 3. Transient (< 3 min) or prolonged (16-24 h) exposure of TG- neonatal stage myocytes to 8-Br-cAMP (300 microM) increased ICa density and caused a shift in the current-voltage relationship to a similar extent to that seen in TG+ mice. In TG+ myocytes, 8-Br-cAMP had no effect. Exposure of TG+ cells to Rp-cAMPS reversed both the shift in voltage dependence and reduced the peak current density observed in these myocytes. We concluded from these results that the L-type Ca2+ channel is maximally modulated by cAMP-dependent protein kinase (PKA) in TG+ mice and that the alpha-MHC promoter is functional in the ventricle as early as embryonic day 14. 4. In contrast, we found that slow delayed rectifier K+ channels were not changed significantly at any of the developmental stages studied by the overexpression of beta2-ARs compared with TG- mice. The sensitivity of murine slow delayed rectifier K+ channels to cAMP was tested by both transient and prolonged exposure to 8-Br-cAMP (300 microM), which increased the slow delayed rectifier K+ channel current (IK,s) density to a similar extent in both TG- and TG+ neonatal myocytes. In addition, we found that there was no difference in the concentration dependence of the response of ICa and IK,s to 8-Br-cAMP. 5. Thus, overexpression of the beta2-AR in the heart results in distinct modulation of ICa, but not IK,s, and this is not due to differences in the 8-Br-cAMP sensitivity of the two channels. Instead, these results are consistent with both compartmentalization of beta2-AR-controlled cAMP and distinct localization of L-type Ca2+ and slow delayed rectifier K+ channels. This cAMP is targeted preferentially to the L-type Ca2+ channel and is not accessible to the slow delayed rectifier K+ channel.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1994

Antifibrillatory effects of clofilium in the rabbit isolated heart.

1. This study was designed to determine whether clofilium exhibits antifibrillatory activity in a pinacidil + hypoxia-induced model of ventricular fibrillation (VF) in Langendorff-perfused hearts. 2. Ten minutes after exposure to vehicle or clofilium (0.1, 1.0 and 10.0 microM), hearts were exposed to pinacidil (1.25 microM), then subjected to 12 min of hypoxia and reoxygenated. Onset to VF was recorded. Additional groups of hearts were pretreated with UK-68,798 (1.0, 3.0 and 10.0 microM), a delayed rectifier channel blocker, and 5-hydroxydecanoate (10 microM), a known ATP-dependent K+ channel blocker, and subjected to an identical protocol. 3. Clofilium decreased the incidence of VF in a concentration-dependent manner; 7/9 control hearts developed VF vs 1/9 hearts (P = 0.007, Fisher's Exact) treated with 10.0 microM clofilium. In addition, 5-hydroxydecanoate protected hearts from VF, while UK-68,798 pretreatment did not. 4. In a separate group of hearts, electrically-induced VF was converted to sinus rhythm in 10/11 hearts after clofilium was introduced as a bolus. 5. Clofilium is capable of preventing VF in the rabbit isolated heart in a concentration-dependent manner. We have data to suggest that the ability of clofilium to attenuate the effects of pinacidil+hypoxia in our model may include blockade of metabolically active K+ channels, i.e., KATP (glibenclamide-sensitive) channel.

Action Potentials↗
PubMed2003

Pressure overload alters stress-strain properties of the developing chick heart.

As a first step in investigating a control mechanism regulating stress and/or strain in the embryonic heart, this study tests the hypothesis that passive mechanical properties of left ventricular (LV) embryonic myocardium change with chronically increased pressure during the chamber septation period. Conotruncal banding (CTB) created ventricular pressure overload in chicks from Hamburger-Hamilton (HH) stage 21 (HH21) to HH27, HH29, or HH31. LV sections were cyclically stretched while biaxial strains and force were measured. Wall architecture was assessed with scanning electron microscopy. In controls, porosity-adjusted stress-strain relations decreased significantly from HH27 to HH31. CTB at HH21 resulted in significantly stiffer stress-strain relations by HH27, with larger increases at HH29 and HH31, and nearly constant wall thickness. Strain patterns, hysteresis, and loading-curve convergence showed few differences after CTB. Trabecular extent decreased with age, but neither extent nor porosity changed significantly after CTB. The stiffened stress-strain relations and constant wall thickness suggest that mechanical load may play a regulatory role in this response.

Animals↗
PubMed1997

Na+/Ca2+ exchange current and contractions measured under Cl(-)-free conditions in developing rabbit hearts.

Previous studies suggesting a greater functional role of cardiac Na+/Ca2+ exchange at birth were performed using tightly buffered free cytosolic Ca2+ concentration ([Ca2+]i). Because Na+/Ca2+ exchange current (INaCa) is influenced by physiological fluctuations in [Ca2+]i, we used conditions of minimally buffered [Ca2+]i to simultaneously record INaCa and cell contractions in single ventricular myocytes isolated from 1 to 27-day-old and adult rabbits. With conventional Cl(-)-containing solutions. Ni(2+)-sensitive outward and inward charge movements were unbalanced, suggesting the presence of a contaminating current (presumably the Ca(2+)-activated Cl- current). Removing Cl- abolished this discrepancy in all age groups and allowed for the accurate quantitation of INaCa. Under Cl(-)-free conditions, outward and inward charge movements were high at birth (4 days: 0.42 +/- 0.03 and -0.38 +/- 0.04 pC/pF, respectively) and decreased postnatally (adult: 0.08 +/- 0.01 and -0.07 +/- 0.01 pC/pF, respectively). Newborn but not adult myocytes contracted during depolarizations in the presence of nifedipine, ryanodine, and thapsigargin. The magnitudes of outward charge movement (Ca2+ influx) and cell shortening exhibited similar voltage dependence, consistent with INaCa-mediated contractions. These results indicate that INaCa can directly support contraction in newborn rabbit ventricular myocytes.

Aging↗
PubMed1998

Development of heart rate irregularities in chick embryos.

Heart rate (HR) irregularities in chick embryos were defined as large fluctuations (>10 beats/min) comprising irregular, brief deceleration and/or acceleration of instantaneous HR (IHR). IHR was determined directly from the arterial blood pressure while adequate gas exchange was maintained through an eggshell and chorioallantoic membrane. Five embryos were examined on each day from day 11 to day 19 of incubation. Baseline HR was stable until day 12-13, and on around day 13-14 transient, rapid deceleration of HR (termed V pattern) began to appear, with a subsequent increase in its frequency and magnitude. The acceleration patterns (lambda, avian omega, and periodic patterns) appeared later, and the IHR became increasingly irregular, with additional, spontaneous deceleration and acceleration patterns toward hatching. Additional experiments with intravenous administration of autonomic drugs clearly showed that rapid deceleration of HR was mediated by parasympathetic nervous function but did not always show clear relations of sympathomimetic and sympathetic blocking agents to the acceleration patterns.

Allantois↗
PubMed2005

Gene expression analysis of ischemic and nonischemic cardiomyopathy: shared and distinct genes in the development of heart failure.

Cardiomyopathy can be initiated by many factors, but the pathways from unique inciting mechanisms to the common end point of ventricular dilation and reduced cardiac output are unclear. We previously described a microarray-based prediction algorithm differentiating nonischemic (NICM) from ischemic cardiomyopathy (ICM) using nearest shrunken centroids. Accordingly, we tested the hypothesis that NICM and ICM would have both shared and distinct differentially expressed genes relative to normal hearts and compared gene expression of 21 NICM and 10 ICM samples with that of 6 nonfailing (NF) hearts using Affymetrix U133A GeneChips and significance analysis of microarrays. Compared with NF, 257 genes were differentially expressed in NICM and 72 genes in ICM. Only 41 genes were shared between the two comparisons, mainly involved in cell growth and signal transduction. Those uniquely expressed in NICM were frequently involved in metabolism, and those in ICM more often had catalytic activity. Novel genes included angiotensin-converting enzyme-2 (ACE2), which was upregulated in NICM but not ICM, suggesting that ACE2 may offer differential therapeutic efficacy in NICM and ICM. In addition, a tumor necrosis factor receptor was downregulated in both NICM and ICM, demonstrating the different signaling pathways involved in heart failure pathophysiology. These results offer novel insight into unique disease-specific gene expression that exists between end-stage cardiomyopathy of different etiologies. This analysis demonstrates that transcriptome analysis offers insight into pathogenesis-based therapies in heart failure management and complements studies using expression-based profiling to diagnose heart failure of different etiologies.

Angiotensin-Converting Enzyme 2↗
PubMed2005

Why do dialysis patients develop a heart of stone and bone of china?

Vascular calcification is a common complication of end-stage renal disease (ESRD). The mechanisms responsible are complex and have so far been considered to be mainly the result of a passive mechanism due to elevated PO(4) levels and high Ca x PO(4) ion product resulting in saturated plasma. However, recent results suggest that also other features, commonly observed in the uremic milieu, such as chronic inflammation, hyperleptinemia and a dysregulation of various mineral-regulating proteins might also contribute to an enhanced calcification process. Moreover, as an inverse relationship between vascular calcification and bone density has been documented in ESRD, it could be speculated that pathologically low bone remodelling (adynamic bone disease) associated with active vitamin D treatment and low parathyroid hormone (PTH) levels may predispose to ectopic calcification of vessels, valves and heart. As patients with vascular calcification have a higher intake of calcium-containing PO(4) binders, novel, non-calcium containing PO(4) binders may diminish the risk of progressive vascular calcification in this patient group. Further studies are needed to elucidate the respective role of chronic inflammation, hyperleptinemia and PTH-lowering therapies in this fatal complication of ESRD.

Bone Density↗
PubMed1993

Role of the circulating and tissue-based renin-angiotensin system in the development of heart failure: implications for therapy.

The renin-angiotensin system (RAS) is believed to play a central role in the pathophysiology of heart failure. However, there is a wide variability in plasma renin levels in patients with heart failure, and normal plasma renin activity has been documented in patients with mild or compensated disease. Recent evidence has demonstrated the existence of endogenous RAS in a number of tissues associated with cardiovascular homeostasis. It is possible that these tissue RAS are activated in the early stages of heart failure when plasma renin activity is normal, and therefore contribute to the progression of this condition. Angiotensin-converting enzyme (ACE) inhibitors reduce both circulating and tissue RAS activity. They are of symptomatic benefit and reduce the mortality associated with heart failure. A number of large studies initiated to investigate the effects of the ACE inhibitor enalapril in patients with all degrees of heart failure have been published recently. These studies show that addition of this drug to therapy significantly decreases patient morbidity and mortality, an effect which is most likely due to the suppression of circulating and tissue RAS activity this agent affords. The relationship of the profile of hormonal suppression seen with enalapril and drug dosage to observed beneficial effects on morbidity or mortality is unclear. Given the large range of alternative ACE inhibitors available, their variable structure, potency and duration of action, the potential for differences between agents needs further consideration. Although direct comparative studies are rare, there is a body of work suggesting that such differentiation may be present and may be of clinical significance.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

Chronotropic and dromotropic actions of acetylcholine on the developing fetal heart.

We studied the effect of acetylcholine (ACh), 1 x 10(-8) to 5 x 10(-7) M, on electrophysiologic characteristics of the isolated (Langendorf), perfused fetal canine heart. ACh induced concentration-dependent decreases in sinoatrial (SA) rate and recovery from overdrive pacing and in atrioventricular (A-V) conduction. These effects of ACh were greater in mid-gestation than late-gestation hearts. The effects of ACh were potentiated by inhibition of acetylcholinesterase by neostigmine, 1 x 10(-7) M, in the late- but not the mid-gestation fetal heart. Decreasing the pH of the perfusion solution from 7.3 to 6.8 potentiated the response to ACh of SA rate and A-V conduction more in mid- than in late-gestation hearts. The response to ACh of the late-gestation fetal canine heart is more sensitive to cholinesterase inhibition whereas the response of the mid-gestation heart is more sensitive to the action of ACh in the presence of acidosis.

Acetylcholine↗
PubMed2002

Angiotensin-(1-7) attenuates the development of heart failure after myocardial infarction in rats.

BACKGROUND: The renin-angiotensin system (RAS) is a key player in the progression of heart failure. Angiotensin-(1-7) is thought to modulate the activity of the RAS. Furthermore, this peptide may play a part in the beneficial effects of angiotensin-converting enzyme inhibitors in cardiovascular disease. We assessed the effects of angiotensin-(1-7) on the progression of heart failure. METHODS AND RESULTS: Male Sprague-Dawley rats underwent either coronary ligation or sham surgery. Two weeks after induction of myocardial infarction, intravenous infusion of angiotensin-(1-7) (24 microg/kg per hour) or saline was started by minipump. After 8 weeks of treatment, hemodynamic parameters were measured, endothelial function was assessed in isolated aortic rings, and plasma angiotensin-(1-7) levels were determined. Myocardial infarction resulted in a significant deterioration of left ventricular systolic and diastolic pressure, dP/dt, and coronary flow. Raising plasma levels 40-fold, angiotensin-(1-7) infusion attenuated this impairment to a nonsignificant level, markedly illustrated by a 40% reduction in left ventricular end-diastolic pressure. Furthermore, angiotensin-(1-7) completely preserved aortic endothelial function, whereas endothelium-dependent relaxation in aortas of saline-treated infarcted rats was significantly decreased. CONCLUSIONS: Angiotensin-(1-7) preserved cardiac function, coronary perfusion, and aortic endothelial function in a rat model for heart failure.

Angiotensin I↗