David J Hearse

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Using the isolated perfused rat heart with transient (10-minute) regional ischemia induced by coronary artery ligation, we have shown that PBN (N-tert-butyl-alpha-phenylnitrone), an organic spin trap agent designed specifically to form "stable" adducts with free radicals in electron spin resonance studies, can dramatically reduce the vulnerability of the(More)
The objective of this study was to determine whether reactive oxygen intermediates (e.g., singlet oxygen and the superoxide radical) can rapidly induce electrophysiological disturbances leading to the genesis of arrhythmias, even in the absence of ischemia and reperfusion. Rat hearts (n = 6 per group) were perfused aerobically at 37 degrees C for 10 minutes(More)
OBJECTIVES Arrhythmias, including ventricular fibrillation (VF), occur in two phases after coronary obstruction, the first during the reversible stage of acute myocardial ischaemia (phase 1) and the second during evolution of the infarct (phase 2). We tested the hypothesis that phase 2 arrhythmias are mediated by actions of neutrophils accumulating within(More)
During cardiac surgery or cardiac transplantation, the heart is subjected to varying periods of global ischemia. The heart must be protected during this ischemic period to avoid additional injury, and techniques have been developed that delay ischemic injury and minimize reperfusion injury. Almost universally, this involves using a hyperkalemic cardioplegic(More)
BACKGROUND Although there are many factors that might contribute to tissue injury during ischemia and reperfusion, the loss of adenine nucleotides has long been considered to be of importance. This has led to the study of interventions designed to limit the loss of nucleotides or to enhance the rate of nucleotide resynthesis during reperfusion.(More)
BACKGROUND We have shown that acadesine (AICAr: 5-amino-4-imidazole carboxamide riboside) improves the early recovery of function of the ischemic and reperfused rat heart. In the present studies we used the transplanted rat heart, with reperfusion for up to 24 hours, to assess whether the beneficial effect of acadesine is a transient or a sustained(More)
Voltage-clamp studies were performed on guinea pig ventricular myocytes to clarify the action of N-(1-[4-(4-fluorophenoxy)butyl]-4-piperidinyl)-N-methyl-2-benzothiazo lamine (R-56865), an inhibitor of cardiac glycoside-induced arrhythmias. Transient inward current ((Iti)) was induced using low-K+/high-Ca2+ Tyrode solution. R-56865 (1 mM) was found to(More)
  • M Yamada, D J Hearse, M J Curtis
  • 1990
We have examined the pathophysiological role of readmission of oxygen (and hence production of oxygen-derived free radicals) in the initiation of reperfusion-induced arrhythmias by separating, on a temporal basis, readmission flow from readmission of oxygen. Isolated rat hearts (n = 12/group) were subjected to 10 minutes of regional ischemia and 10 minutes(More)
It has been proposed that increases in tissue cyclic adenosine monophosphate during ischemia may be responsible for the induction of arrhythmias that occur during the early minutes of ischemia. We have tested this hypothesis using the isolated perfused rat heart with coronary artery occlusion for 30 minutes. In control hearts, after a transient small rise,(More)
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