排序方式: 共有164条查询结果,搜索用时 0 毫秒
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TJ Tucker SF Brady WC Lumma SD Lewis SJ Gardell AM Naylor-Olsen Y Yan JT Sisko KJ Stauffer BJ Lucas JJ Lynch JJ Cook MT Stranieri MA Holahan EA Lyle EP Baskin IW Chen KB Dancheck JA Krueger CM Cooper JP Vacca 《Canadian Metallurgical Quarterly》1998,41(17):3210-3219
As part of an ongoing effort to prepare therapeutically useful orally active thrombin inhibitors, we have synthesized a series of compounds that utilize nonbasic groups in the P1 position. The work is based on our previously reported lead structure, compound 1, which was discovered via a resin-based approach to varying P1. By minimizing the size and lipophilicity of the P3 group and by incorporating hydrogen-bonding groups on the N-terminus or on the 2-position of the P1 aromatic ring, we have prepared a number of derivatives in this series that exhibit subnanomolar enzyme potency combined with good in vivo antithrombotic and bioavailability profiles. The oxyacetic amide compound 14b exhibited the best overall profile of in vitro and in vivo activity, and crystallographic studies indicate a unique mode of binding in the thrombin active site. 相似文献
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The hypothalamo-pituitary-adrenal (HPA) axis is modulated by sex hormones. Few data exist on the relation between acute estrogen deficit and HPA axis response to corticotropin-releasing hormone (CRH). The effects of a sudden drop in estradiol levels on basal and CRH-stimulated levels of ACTH, cortisol, testosterone, androstenedione and 17-hydroxyprogesterone (17-OHP) were assessed in nine premenopausal women (44-48 years of age), before and after ovariectomy. The CRH test was performed before and 8 days after ovariectomy. A significant reduction in ACTH and adrenal steroids but not in cortisol response to CRH was observed after ovariectomy. The ratio of deltamax androstenedione/17-OHP after CRH stimulation was substantially the same before and after ovariectomy, whereas deltamax 17-OHP/cortisol was significantly lower in ovariectomized women showing increased 21- and 11beta-hydroxylase activity. The results show that the acute estrogen deficit induces changes in the HPA axis characterized by reduced stimulated secretion of ACTH and steroids but normal stimulated cortisol production. 相似文献
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A liquid chromatographic method for the determination of the enantiomers of mefloquine has been improved. The chromatography involved two columns: an achiral cyanopropyl stationary phase for the quantification of (+/-)-mefloquine and a chiral naphthyl-urea stationary phase for the determination of the enantiomeric ratio. Compared with the previous method, which needed two detectors, this one used one detector-integrator to which the two columns are connected alternately by an automated column-switching system. The method is suitable for the quantification (0.05 microgram/ml) of mefloquine and the determination of enantiomeric ratios from 500-microliters plasma samples with ultraviolet detection. 相似文献
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IW Brown 《Canadian Metallurgical Quarterly》1999,60(1):22-25
BACKGROUND: Attentional processes are assumed to play an important role in the maintenance of illness anxiety, although empirical support is relatively scarce. METHODS: The present study explores the relationship between selective attention (i.e. private body consciousness and symptom reporting), intensive concentration (i.e. attentional control and sustained attention), and illness anxiety in 57 non-clinical subjects. RESULTS: Zero-order and multiple correlations suggest that illness anxiety is significantly related to cognitive failures in everyday life and private body consciousness and to a lesser extent to symptom reporting. CONCLUSION: It is concluded that illness anxiety can be partly predicted from specific attentional variables. However, specific operationalizations of attentional parameters seems to determine the existence and magnitude of these relations. 相似文献
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Glutathione (GSH) synthetase (Gsh2) catalyzes the ATP-dependent synthesis of GSH from gamma-glutamylcysteine (gamma-Glu-Cys) and glycine. GSH2, encoding the Saccharomyces cerevisiae enzyme, was isolated and used to construct strains that either lack or overproduce Gsh2. The identity of GSH2 was confirmed by the following criteria: 1) the predicted Gsh2 protein shared 37-39% identity and 58-60% similarity with GSH synthetases from other eukaryotes, 2) increased gene dosage of GSH2 resulted in elevated Gsh2 enzyme activity, 3) a strain deleted for GSH2 was dependent on exogenous GSH for wild-type growth rates, and 4) the gsh2 mutant lacked GSH and accumulated the dipeptide gamma-Glu-Cys intermediate in GSH biosynthesis. Overexpression of GSH2 had no effect on cellular GSH levels, whereas overexpression of GSH1, encoding the enzyme for the first step in GSH biosynthesis, lead to an approximately twofold increase in GSH levels, consistent with Gsh1 catalyzing the rate-limiting step in GSH biosynthesis. In contrast to a strain deleted for GSH1, which lacks both GSH and gamma-Glu-Cys, the strain deleted for GSH2 was found to be unaffected in mitochondrial function as well as resistance to oxidative stress induced by hydrogen peroxide, tert-butyl hydroperoxide, and the superoxide anion. Furthermore, gamma-Glu-Cys was at least as good as GSH in protecting yeast cells against an oxidant challenge, providing the first evidence that gamma-Glu-Cys can act as an antioxidant and substitute for GSH in a eukaryotic cell. However, the dipeptide could not fully substitute for the essential function of GSH in the cell as shown by the poor growth of the gsh2 mutant on minimal medium. We suggest that this function may be the detoxification of harmful intermediates that are generated during normal cellular metabolism. 相似文献
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This study extended Hanin's 1980 Zone of Optimal Functioning hypothesis by assessing both intensity and direction components of competitive state anxiety. 20 volunteer semiprofessional cricketers responded to the modified Competitive State Anxiety Inventory-2 prior to ten matches. For each game, players' performances were intraindividually evaluated by three qualified cricket coaches using subjective criteria. Separate Cognitive Anxiety and Somatic Anxiety 'below,' 'in,' and 'above' zones for Intensity and Direction of state anxiety were identified via repeated empirical assessments. Two two-way analyses of variance were computed for Intensity and Direction of anxiety (Cognitive Anxiety Zone Level x Somatic Anxiety Zone Level) with standardized performance scores as the dependent variable. A significant interaction was found between the zone levels for Cognitive and Somatic Anxiety Direction and performance scores. Examination of the Zone of Optimal Functioning hypothesis that focuses on the interactions between Cognitive and Somatic Anxiety and in particular the directional elements of the modified inventory seems warranted. 相似文献