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排序方式: 共有469条查询结果,搜索用时 31 毫秒
91.
B H Jenks R W McKee M E Swendseid B Faraji W G Figueroa R A Clemens 《The American journal of clinical nutrition》1987,46(3):496-502
Five healthy males, age 25-32 y, were fed in sequence a diet of ordinary foods (10 d, PI), a low-methionine diet (285 mg/d, 14 d, PII), and an adequate-methionine diet (725 mg/d, 7 d, PIII). Diets contained 9 g nitrogen (N) per day with soy protein and synthetic L-amino acids as the N sources in PII and PIII. In PII, subjects were in negative N balance whereas, in PIII, four subjects were in positive N balance. On the last day of each period, fasting subjects ingested a dose of nicotinamide (NAM, 102 mumol/kg body wt). Plasma and urine samples were analyzed for methylated derivatives of NAM by high-performance liquid chromatography (HPLC) methods. Mean values of methylated metabolites in urine from the three diet periods (for four subjects in N balance during PIII) were not different (59.8, 56.7, and 59.9 mumol/(kg body wt X 24 h) for PI, PII, and PIII, respectively). Plasma values of these metabolites also were similar. Results suggest that during a 2-wk period of negative N balance due to a low-methionine intake hepatic methylation processes are not impaired. These processes appear to have a higher metabolic priority than maintenance of the net protein synthesis rate. 相似文献
92.
Extra-contractual referrals (ECRs) can be a cause of considerable anxiety to purchasing authorities, mainly because of their potential to generate unexpected expenditure. But ECRs can also be used as a tool for monitoring the demand for, and quality of, clinical services. ECRs were studied in the Darlington Health Authority district using a variety of methods including inter-disciplinary meetings, a series of interviews with local GPs, and a questionnaire to general practitioners on 230 consecutive ECRs. The methods and results of the questionnaire study are presented. The commonest reasons for making ECRs included the mistaken belief that a contract existed with the ECR provider, patient dissatisfaction with the local provider, and referral to benefit from shorter waiting lists. ECRs for bone-mass densitometry, orthopaedics, and ear nose and throat services were over-represented. Questionnaire results were validated by comparison with an interview study of all GPs in the district. We conclude that trends in ECRs can be monitored as a convenient ‘early warning system’ to alert purchasing authorities to changes in demand or perceived problems with local provider units. ECR data must be interpreted in the context of further local background information from sources such as GPs and public health physicians. In the case of Darlington, scrutiny of ECRs has led to changes in services and contracts. 相似文献
93.
94.
Cardiac herniation with volvulus is a catastrophic complication of right intrapericardial pneumonectomy. This case illustrates diagnostic radiographic findings that may be essential for early diagnosis and survival, since the clinical signs are nonspecific. 相似文献
95.
Sincetheintroductionofthefirstlineofangiotensinconvertingenzyme(ACE)inhibitors,ofwhichcaptoprilistheprototype,morepotentlonger-lastingagentshavebecomeavailable[l].AmongtheseisramipriIat,anonsL1lfhydrylACEinhibitorsimilarchemicallytoenalaprilatbutcontaininginadditionapentanering.Benderetal[2Jdemonstratedinvitrothatramiprilatisatleast23timesmorelipophilicthanenalaprilatwithanaffinityforACE47timesgreatc'rthanthatofcaptopril.ItwaspostulatedthatthemorelipophiIicanACEinhibitor,thebetteraccessi… 相似文献
96.
The release of melanophore stimulating hormone (MSH) from the pars intermedia of the amphibian Xenopus laevis is regulated by multiple factors of hypothalamic origin. The aim of this study was to determine if potential secretagogues function through a direct action on the melanotrope cell. For this purpose an in vitro superfusion system containing isolated melanotropes (cell suspension) was utilized. The viability of the cells in suspension was tested by examining their ability to synthesize, process and release pro-opiomelanocortin (POMC) related peptides. All biosynthetic functions appeared normal, with the exception that the isolated melanotropes are unable to N-terminally acetylate MSH. Release of immunoreactive-MSH from these cells was shown to be Ca2+-dependent and high K+ stimulated release. Both the neurotransmitters dopamine and γ-aminobuiyric acid (GABA), which are thought to be physiologically important MSH-release inhibiting factors, were shown to inhibit MSH release from isolated melanotropes. Dopamine appeared to function through a dopamine D2 type receptor mechanism while for GABA, both a GABAa and GABAb receptor mechanism are involved. 相似文献
97.
Richard J. Jenks 《Archives of sexual behavior》1998,27(5):507-521
No review of the topic of swinging has been done in the last 20 years. This review is intended to update the literature. Studies estimating the incidence of swinging, the demographic and personality characteristics of swingers, along with how swingers are perceived by nonswingers are reviewed. Numerous theories explaining this behavior have been presented with a social psychological model being the primary focus here. Major reasons for getting involved in swinging, initiation into the lifestyle, effects on marriage, and dropping out of swinging are also covered. Finally, the literature dealing with some of the major problems with swinging, focusing on AIDS, are also discussed, along with the current state of swinging and suggestions for future research. 相似文献
98.
99.
A new type of delta beta-thalassemia characterized by decreased expression of the beta-globin gene and increased expression of both G gamma and A gamma globin gene in the absence of a detectable deletion has recently been described in the Chinese population. In this study we characterize the mutant beta-globin gene from this delta beta- thalassemia chromosome. An A to G transversion is identified in the "ATA" sequence of the promoter region that leads to decreased expression of the beta-globin gene in vivo and in vitro. We also demonstrate the presence of this mutation in every individual with a high fetal hemoglobin phenotype in this family and its absence in every individual with a normal hemoglobin phenotype. This same promoter mutation has recently been detected in Chinese beta-thalassemia genes where it is present on chromosomes of the same haplotype as that of the delta beta-thalassemia chromosome we are studying. These data support the hypothesis that an as yet unidentified mutation occurred on the ancestral chromosome carrying the promoter mutation and subsequently gave rise to the delta beta-thalassemia phenotype. 相似文献
100.
Richard J. Jenks 《Archives of sexual behavior》1985,14(6):517-527
One objective was to test two of the major theories of swinging. The first, rooted in the concept of marginality, is based on the idea that swingers are relatively new to their communities and to the middle class. The second has argued that swingers are more likely to be less attached to the community and the institutions in society. A third theory takes a more social psychological approach, viewing swingers within an emergent situation. However, this approach does not include any predisposing factors. A second objective, therefore, was to analyze the effects of a predisposing variable thought to be important in swinging—jealousy.A group of 114 swingers, along with a control group of 114 nonswingers, responded to a questionnaire containing a number of demographic and attitudinal items. Results indicated that swingers, compared to nonswingers, had lived in their communities for fewer years, had moved more often within the past 5 years, and identified less with religion. However, swingers were no different on political identification or newness to the middle class. And, contrary to expectations, swingers belonged to more community organizations than nonswingers and responded in a less alienated fashion on two items. When jealousy was introduced, it was found that swingers perceived themselves as less jealous than nonswingers and that nonjealous swingers were more liberal than nonjealous nonswingers on a number of attitudinal items.Finally, a social psychological model of swinging, including predisposing factors, is presented. 相似文献