Holly A Shiels

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Proapoptotic Bcl-2 family members have been proposed to play a central role in regulating apoptosis. However, mice lacking bax display limited phenotypic abnormalities. As presented here, bak(-/-) mice were found to be developmentally normal and reproductively fit and failed to develop any age-related disorders. However, when Bak-deficient mice were mated(More)
The sarcoplasmic reticulum (SR) is central to intracellular Ca2+ regulation during excitation–contraction (E-C) coupling in mammalian cardiac tissue. The importance of the SR to E-C coupling in lower vertebrates is less certain. This uncertainty can be attributed, in part, to the temperature-dependency of the SR Ca2+-release channel and to interspecific(More)
Numerous studies have examined the effect of temperature on in vivo and in situ cardiovascular function in trout. However, little information exists on cardiac function at temperatures near the trout’s upper lethal limit. This study measured routine and maximum in situ cardiac performance in rainbow trout (Oncorhynchus mykiss) following acclimation to 15,(More)
Ultrastructure, molecular composition and electrophysiological properties of cardiac myocytes and functional characteristics of the fish heart suggest that cycling of extracellular Ca(2+) is generally more important than intracellular cycling of Ca(2+) stores of the sarcoplasmic reticulum (SR) in activating contraction of fish cardiac myocytes. This is(More)
CTLA-4 is expressed on T cells after activation and shares homology with the CD28 costimulatory receptor. In contrast to CD28, CTLA-4 is thought to be a negative regulator of T cell activation. Cross-linking of CTLA-4 during activation of peripheral T cells reduces IL-2 production and arrests T cells in G1. Much less is known about the function of CTLA-4 in(More)
The zebrafish is widely used for human related disease studies. Surprisingly, there is no information about the electrical activity of single myocytes freshly isolated from adult zebrafish ventricle. In this study, we present an enzymatic method to isolate ventricular myocytes from zebrafish heart that yield a large number of calcium tolerant cells.(More)
Rainbow trout remain active in waters that seasonally change between 4°C and 20°C. To explore how these fish are able to maintain cardiac function over this temperature range we characterized changes in cardiac morphology, contractile function, and the expression of contractile proteins in trout following acclimation to 4°C (cold), 12°C (control), and 17°C(More)
The baculovirus inhibitor of apoptosis gene, iap, can impede cell death in insect cells. Here we show that iap can also prevent cell death in mammalian cells. The ability of iap to regulate programmed cell death in widely divergent species raised the possibility that cellular homologs of iap might exist. Consistent with this hypothesis, we have isolated(More)
Bluefin tuna have a unique physiology. Elevated metabolic rates coupled with heat exchangers enable bluefin tunas to conserve heat in their locomotory muscle, viscera, eyes and brain, yet their hearts operate at ambient water temperature. This arrangement of a warm fish with a cold heart is unique among vertebrates and can result in a reduction in cardiac(More)