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排序方式: 共有518条查询结果,搜索用时 15 毫秒
51.
Summary Ultrastructural studies of palatal shelves of Tuck A mice embryos aged 12.25–14.25 days show discontinuities of the epithelial basement membrane traversed by epithelial cell processes before the onset of midline degenerative changes. 相似文献
52.
D. W. Johnson G. Phillipou I. A. Blair R. F. Seamark 《Cellular and molecular life sciences : CMLS》1979,35(9):1261-1262
Summary The urinary production rate of pregnenolone has been determined for a male subject using 7,7-d2-pregnenolone as an isotopic tracer.To whom correspondence should be addressed. 相似文献
53.
Inactivation of yeast glucose-6-P dehydrogenase by aspirin 总被引:1,自引:0,他引:1
P. F. Han G. Y. Han H. C. McBay J. Johnson Jr 《Cellular and molecular life sciences : CMLS》1980,36(10):1149-1150
Summary Glucose-6-P dehydrogenase is irreversibly inactivated by treatment with Na salts of aspirin. Kinetic data show that 1 molecule of aspirin reacts with each active unit when the enzyme is inactivated. The rate of inactivation is enhanced with increasing pH but is reduced in the presence of glucose-6-P or NADP+. Na salicylate fails to inactivate the enzyme.This work was supported by grant RR-8006 from the General Research Branch, Division of Research Resources, NIH (USA). 相似文献
54.
55.
Cloning and sequence analysis of the cDNA for the rat atrial natriuretic factor precursor 总被引:4,自引:0,他引:4
M Yamanaka B Greenberg L Johnson J Seilhamer M Brewer T Friedemann J Miller S Atlas J Laragh J Lewicki 《Nature》1984,309(5970):719-722
Atrial extracts contain factors which induce potent natriuresis changes in renal haemodynamics, and relax pre-contracted vascular smooth muscle. Low-molecular-weight peptides which mimic these actions have now been purified by several groups, including ours (see accompanying paper), and higher-molecular-weight proteins with similar but less potent biological activities have also been identified and are presumed to be precursors. If released into the circulation, these peptides, collectively called atrial natriuretic factor (ANF), may play a significant part in blood-pressure homeostasis, regulation of extracellular fluid volume and as antagonists to the hypertensive effects of the renin-angiotensin system and other hormonal and neurotransmitter systems. We describe here the isolation and characterization of rat atrial cDNA clones which encode ANF. Nucleotide sequence analysis shows that auriculin corresponds to the 25 amino acids located close to the C-terminus of a 152-amino acid ANF precursor. Analysis of the in vitro translation products of precursor ANF mRNA suggests that multiple forms of the precursor may exist. 相似文献
56.
57.
P. F. Han S. H. Pollock H. W. Matthews J. Johnson Jr 《Cellular and molecular life sciences : CMLS》1979,35(5):586-587
Summary Treatment of turkey liver fructose-1,6-bisphosphatase with penicillin G progressively inactivated the enzyme and desensitized the enzyme toward high substrate inhibition. The treatment also led to reduced sensitivity to AMP inhibition and the loss of cooperative interaction among AMP-binding sites. These altered properties were not reversed by dialysis, but were prevented when treatment with penicillin G was performed in the presence of substrate.This work was in part supported by grant RR-8006 from the General Research Branch, Division of Research Resources, NIH (USA) and in part by Faculty Research Grant from Southern School of Pharmacy, Mercer University, Atlanta (Georgia, USA). 相似文献
58.
D. R. Johnson 《Cellular and molecular life sciences : CMLS》1977,33(4):517-518
Summary In an experiment designed to test the possible correlation between hard water and neural tube anomalies, high calcium intake was found to increase the number of exencephalic foetuses in litters from trypan blue treated mice. This is a reversal of the suggested trend in man where soft water and anencephaly may be correlated. 相似文献
59.
Purification, sequencing and synthesis of natriuretic and vasoactive rat atrial peptide 总被引:3,自引:0,他引:3
S A Atlas H D Kleinert M J Camargo A Januszewicz J E Sealey J H Laragh J W Schilling J A Lewicki L K Johnson T Maack 《Nature》1984,309(5970):717-719
Mammalian atria contain potent natriuretic and diuretic substances which exist in high- and low-molecular-weight forms and which appear to be associated with atrium-specific granules. The natriuretic effect of atrial extract is largely accountable for by its renal haemodynamic effects; atrial extracts also antagonize hormone- and non-hormone-induced contraction of the isolated rabbit aorta and isolated rat kidney vasculature. We have completely purified a low-molecular-weight natriuretic and vasoactive substance from rat atria and characterized it as a 24-amino acid peptide. Synthetic peptide, produced by solid-phase synthesis, mimics biological effects of crude atrial extract and purified peptide; its activity is enhanced by slow oxidation, suggesting a disulphide (Cys 4-Cys 20) configuration for the native peptide. If secreted into blood, this atrial natriuretic peptide (' auriculin B') could be a novel peptide hormone of considerable importance to renal and cardiovascular homeostasis. 相似文献
60.
I. T. Johnson 《Cellular and molecular life sciences : CMLS》1976,32(3):347-348
Summary The total fluid uptake of everted sacs of rat jejunum was compared in animals killed by stunning and decapitation, or anaesthetised with ether. Fluid transport was significantly higher in the tissue prepared from stunned and decapitated animals. It is suggested that etherization may have adverse effects on the physiological viability of subsequently isolated tissues. 相似文献