T. A. Fralix

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Preconditioning with brief intermittent periods of ischemia before a sustained period of ischemia has been shown to reduce infarct size and improve recovery of function in rat hearts. The mediators of this protective response are unknown in rats. We tested the hypothesis that a lipoxygenase metabolite might be involved in preconditioning, since lipoxygenase(More)
Increased concentrations of intracellular H+, Na+, and Ca2+ have been observed during ischemia, and these ionic alterations have been correlated with several indexes of cell injury in a number of studies. Recently, adenosine was proposed to play a role in ischemic preconditioning, since adenosine antagonists block the protective effects of these brief(More)
Preconditioning with brief intermittent periods of ischemia has been shown to lessen the detrimental effects of a subsequent sustained (30-60 min) period of ischemia. Because adenosine has been suggested to be the mediator of preconditioning, we were interested in investigating whether adenosine antagonists would block the effect of preconditioning on ionic(More)
Magnetization transfer between macromolecules and water can be a significant factor contributing to tissue water 1H relaxation. Using saturation transfer techniques, the degree of magnetization transfer between the macromolecular matrix and bulk water 1H can be directly measured and magnetization transfer contrast (MTC) can be generated in MR images. A(More)
BACKGROUND The relationships between the metabolic, ionic, and electrical changes of acute ischemia have not been determined precisely because they have been studied under different experimental conditions. We used ion-selective electrodes, nuclear magnetic resonance spectroscopy, and the four-electrode method to perform four series of experiments in the(More)
Increases in cytosolic free calcium concentration ([Ca2+]I) may play an important role in myocardial ischemic injury. An early effect of the rise in [Ca2+]I may be impaired postischemic contractile function if the ischemic myocardium is reperfused during the reversible phase of ischemic injury; furthermore, if the rise in [Ca2+]I is prolonged, a cascade of(More)
Myocardial O2 consumption (MVO2) was stimulated up to two-fold by either increasing afterload or beta-receptor stimulation in working normothermic isolated rabbit hearts while noninvasively monitoring the O2 delivery or phosphate compounds (total n = 48). Intracellular O2 delivery was estimated with the use of myocardial optical absorbance changes centered(More)
The mechanisms that contribute to myocardial cell injury are not well understood. Furthermore, the ability of reperfusion conditions to modify ischemic injury is unclear. Recent studies have indicated that glucose utilization may improve ionic homeostasis. Because considerable derangement of ion concentrations occurs during ischemia, glucose utilization may(More)
Intracellular calcium has been proposed to play a key role in the orchestration of metabolic rate with contractile activity in the mammalian heart. Calcium is believed to accomplish this task by modulating the contractile apparatus as well as the metabolic process directly, and perhaps simultaneously, during alterations in cardiac work. The purpose of this(More)