Joseph R. Libonati

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BACKGROUND Cardiac responses to beta-adrenergic receptor stimulation are depressed with pressure overload-induced cardiac hypertrophy. We investigated whether exercise training could modify beta-adrenergic receptor responsiveness in a model of spontaneous hypertension by modifying the beta-adrenergic receptor desensitizing kinase GRK2 and the abundance and(More)
We examined the effects of two exercise training modalities, i.e., low-intensity endurance and sprint running, on in vitro, isovolumic myocardial performance following ischemia and reperfusion. Rats ran on a treadmill 5 d.wk-1 for 6 wk at the following levels: endurance; 20 m.min-1, 0% grade, 60 min.d-1 and sprint; five 1-min runs at 75 m.min-1, 15% grade(More)
There are several important links between aerobic exercise performance and the diastolic phase of the cardiac cycle. During acute exercise, diastolic function must be augmented in order for left ventricular filling to match increased left ventricular output, i.e., cardiac output. This challenges the myocardium because the shortened duration of diastole(More)
The purpose of this study was to investigate whether overweight students achieved a lower relative degree of scholastic achievement compared to nonoverweight students. Subjects consisted of 6th and 7th grade students enrolled in a large public middle school in a suburb of Philadelphia, Pennsylvania. We compared grade point averages (GPAs), nationally(More)
BACKGROUND Left ventricular cavity dimension, wall thickness, relaxation, and filling increase with exercise training and have a role in enhancing physical performance. We probed whether changes in diastole may develop separately from those in cardiac morphometry and still contribute to improve physical performance. Challenging diastole by preload reduction(More)
OBJECTIVE Angiotensin II (ANG II) has recently been reported to increase inotropy in adult rabbit myocytes by a mechanism of alkalinization and consequent increased myofilament sensitivity to calcium. Accordingly, we tested the hypothesis that ANG II would have a greater inotropic effect during ischemic conditions than it would during normoxia, since(More)
Glucagon like peptide-1 (7-36) amide (GLP-1) is an incretin hormone with multiple salutary cardiovascular effects. A short course of the GLP-1 analogue Exendin-4 (Ex-4) in the neonatal period prevents the development of mitochondrial dysfunction and oxidative stress in a rat prone to obesity and diabetes. We sought to evaluate whether neonatal Ex-4 can(More)
INTRODUCTION Exercise training induces significant changes in the performance of skeletal muscle. PURPOSE To determine whether changes in the gene expression of rat hind-limb muscle sarcoplasmic reticulum Ca2+ -ATPase isoforms (SERCA1a and SERCA2a) in response to either moderate- or high-intensity exercise training underlie the functional remodeling. (More)
Calcineurin, a Ca(2+)-regulated protein phosphatase, links myocardial Ca(2+) signaling with hypertrophic gene transcription. Calcineurin abundance increases in pressure-overload hypertrophy and may reduce agonist-mediated phospholamban (PLB) phosphorylation to underlie blunted beta-adrenergic receptor (beta-AR) responsiveness in hypertension. This(More)
We evaluated the effects of nutrient enriched medium and hemoglobin based oxygen carrier (HBOC) upon myocardial functional recovery after 15 minutes of warm ischemia in an isovolumic Langendorff rat heart model. Hearts (n = 8/group) were perfused at constant pressure (90 mm Hg) with Krebs-Henseleit buffer or HEPES modified cell culture medium (M199) in the(More)