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71.
B. T. Firth J. S. Turner C. L. Ralph 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1989,159(1):13-20
Summary Thermal selection by collared lizards (Crotaphytus collaris) and chuckawallas (Sauromalus obesus) was studied in continuously operating laboratory thermal gradients in a 12L12D photoperiod in spring-summer. In both species, selected temperatures above the median were higher during the day than at night. Below the median selected temperature, however, nighttime temperature significantly exceeded daytime temperature in chuckawallas but not in collared lizards. Pinealectomized collared lizards selected significantly lower temperatures than sham-operated or intact controls. This effect was most pronounced at night. Pinealectomy had no effect on the temperatures selected by chuckawallas. The significance of these results is discussed in relation to the seasonal life-history strategy of these two species. 相似文献
72.
W. W. Parmley K. Chatterjee G. S. Francis B. G. Firth R. A. Kloner 《The Western journal of medicine》1991,154(4):427-441
Congestive heart failure is a common syndrome with high mortality in its advanced stages. Current therapy includes the use of vasodilator drugs, which have been shown to prolong life. Despite current therapy, mortality remains high in patients with severe heart failure. Potent new inotropic vasodilators have improved ventricular performance but have not prolonged life in patients with end-stage heart failure. Serious arrhythmias are implicated in the sudden deaths of 30% to 40% of patients with severe heart failure, but the benefits of antiarrhythmic therapy have not been established. Upcoming trials will address this question. Ventricular remodeling and progressive dilatation after myocardial infarction commonly lead to congestive heart failure; early unloading of the ventricle with an angiotensin-converting enzyme inhibitor may attenuate these events. These findings support the concept that angiotensin-converting enzyme inhibitors may be useful in managing heart failure of all degrees of severity, including left ventricular dysfunction and end-stage heart failure. Part of the damage that may occur with acute myocardial infarction, particularly in this era of thrombolysis therapy, is reperfusion injury, which may be mediated by oxygen-derived free radicals. Better knowledge of the mechanisms and treatment of myocardial infarction, the leading cause of congestive heart failure, may help prevent or attenuate the development of this syndrome. 相似文献
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A homologous family of UDP- N -acetylgalactosamine: polypeptide N -
acetylgalactosaminyltransferases (GalNAc-transferases) initiate O-
glycosylation. These transferases share overall amino acid sequence
similarities of approximately 45-50%, but segments with higher similarities
of approximately 80% are found in the putative catalytic domain. Here we
have characterized the genomic organization of the coding regions of three
GalNAc-transferase genes and determined their chromosomal localization. The
coding regions of GALNT1 , -T2 , and -T3 were found to span 11, 16, and 10
exons, respectively. Several intron/exon boundaries were conserved within
the three genes. One conserved boundary was shared in a homologous C.
elegans GalNAc- transferase gene. Fluorescence in situ hybridization showed
that GALNT1 , -T2 , and -T3 are localized at chromosomes 18q12-q21,
1q41-q42, and 2q24-q31, respectively. These results suggest that the
members of the polypeptide GalNAc-transferase family diverged early in
evolution from a common ancestral gene through gene duplication.
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