Shawn W. Robinson

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Drug-induced triggered arrhythmias in heart muscle involve oscillations of membrane potential known as delayed or early afterdepolarizations (DADs or EADs). We examined the mechanism of DADs and EADs in ferret ventricular muscle. Membrane potential, tension and aequorin luminescence were measured during exposure to elevated [Ca2+]0, strophanthidin and/or(More)
OBJECTIVES The goal of this study was to determine the prevalence of depression in an out-patient heart failure (HF) population; its relationship to quality of life (QOL); and the impact of gender, race, and age. BACKGROUND Most studies of depression in HF have evaluated hospitalized patients (a small percentage of the population) and have ignored the(More)
BACKGROUND Coenzyme Q10 is commonly used to treat congestive heart failure on the basis of data from several unblinded, subjective studies. Few randomized, blinded, controlled studies have evaluated objective measures of cardiac performance. OBJECTIVE To determine the effect of coenzyme Q10 on peak oxygen consumption, exercise duration, and ejection(More)
The signaling pathway that transduces the stimulatory effect of low K+ on the biosynthesis of Na,K-ATPase remains largely unknown. The present study was undertaken to examine whether reactive oxygen species (ROS) mediated the effect of low K+ in Madin-Darby canine kidney (MDCK) cells. Low K+ increased ROS activity in a time- and dose-dependent manner, and(More)
BACKGROUND Congestive heart failure (CHF) and depression are independently known to result in physical decline and diminished functional capacity in the general population. The prevalence and relationship of depressive symptoms in CHF to physical limitations has not been objectively examined. METHODS AND RESULTS The Center for Epidemiological Studies(More)
The Na(+) current component I(Ca(TTX)) is functionally distinct from the main body of Na(+) current, I(Na). It was proposed that I(Ca(TTX)) channels are I(Na) channels that were altered by bathing media containing Ca(2+), but no, or very little, Na(+). It is known that Na(+)-free conditions are not required to demonstrate I(Ca(TTX).) We show here that(More)
Much evidence suggests that caffeine/ryanodine (Caf/Ry)-releasable and inositol-1,4,5-trisphosphate (InsP3)-releasable Ca2+ stores in the sarcoplasmic reticulum (SR) of smooth muscles are at least partially distinct. We directly visualized SR stores in primary-cultured rat mesenteric artery myocytes with high-resolution digital imaging and the low-affinity(More)
BACKGROUND Exercise programs for patients with heart failure have often enrolled and evaluated relatively healthy, young patients. They also have not measured the impact of exercise performance on daily activities and quality of life. METHODS AND RESULTS We investigated the impact of a 6-month supervised and graded exercise program in 33 elderly patients(More)
Foxglove and its constituents therapeutic agent digitalis have been used for centuries for the treatment of heart failure. All digitalis-like cardiotonic steroids enhance heart contraction through a mechanism involving the inhibition of the Na(+),K(+)- ATPase. Recently, Rathore and colleagues reported that sex-based differences may exist in the efficacy of(More)