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排序方式: 共有459条查询结果,搜索用时 15 毫秒
41.
The in vivo kinetics of the HDL apolipoproteins (apo) A-I and A-II were studied in six subjects with impaired glucose tolerance (IGT) and six control subjects with normal glucose tolerance (NGT), using a stable isotope approach. During a 12-h primed constant infusion of L-[ring-13C6]-phenylalanine, tracer enrichment was determined in apoA-I and apoA-II from ultracentrifugally isolated HDL. The rates of HDL apoA-I and apoA-II production and catabolism were estimated using a one-compartment model-based analysis. Triglycerides were higher in IGT subjects (1.33 +/- 0.21 vs. 0.84 +/- 0.27 mmol/l, P < 0.05), but were within the normal range. HDL cholesterol and apoA-I levels were significantly lower in subjects with IGT (1.07 +/- 0.15 vs. 1.36 +/- 0.14 mmol/l, P < 0.05; 0.94 +/- 0.10 vs. 1.34 +/- 0.07 g/l, P < 0.01). In IGT subjects, HDL composition was significantly altered, characterized by an increase in HDL triglycerides (4.9 +/- 1.9 vs. 3.2 +/- 1.0%, P < 0.05) and HDL phospholipids (34.7 +/- 2.6 vs. 27.5 +/- 5.8%, P < 0.05) and a decrease in HDL cholesteryl esters (10.1 +/- 2.0 vs. 12.7 +/- 2.9%, P < 0.05) and HDL apoA-I (31.5 +/- 4.4 vs. 43.2 +/- 2.4%, P < 0.05). The mean fractional catabolic rate (FCR) of HDL apoA-I was significantly higher in IGT subjects (0.34 +/- 0.05 vs. 0.26 +/- 0.03 day(-1), P < 0.01), while the HDL apoA-I production rate (PR), as well as the PR and FCR of HDL apoA-II, showed no differences between the two groups. There were significant correlations between HDL apoA-I FCR and the following parameters: HDL apoA-I (r = -0.902, P < 0.001), HDL cholesterol (r = -0.797, P = 0.001), plasma triglycerides (r = 0.743, P < 0.01), HDL triglycerides (r = 0.696, P < 0.01), and cholesterol ester transfer protein activity (r = 0.646, P < 0.01). We observed a strong positive association between increased apoA-I catabolism and insulin (r = 0.765, P < 0.01) and proinsulin (r = 0.797, P < 0.01) concentrations. These data support the hypothesis that the decrease in HDL cholesterol and apoA-I levels in IGT is principally the result of an enhanced apoA-I catabolism. The latter seems to be an early metabolic finding in IGT even when other lipid parameters, especially plasma triglycerides, still appear to be not or only weakly affected. 相似文献
42.
JC Virchow P Julius M Lommatzsch W Luttmann H Renz A Braun 《Canadian Metallurgical Quarterly》1998,158(6):2002-2005
The mechanisms linking inflammation and airway hyperresponsiveness in allergic bronchial asthma are still not completely defined. Since neurotrophic factors increase nerve excitability and neurotransmitter synthesis and are produced by immunocompetent cells, they are likely candidates as mediators of inflammation and hyperresponsiveness. We tested the hypothesis that neurotrophin concentrations will increase in the bronchoalveolar lavage (BAL) fluid from patients with asthma after segmental allergen provocation. For this purpose an individually standardized dose of allergen or saline was instilled into different segments during bronchoscopy in eight subjects with mild allergic bronchial asthma. Segments were then lavaged 10 min and 18 h after allergen challenge or saline instillation. There was a significant increase in the neurotrophins nerve growth factor, brain-derived neurotrophic factor, and neurotrophin-3 in BAL fluids 18 h after allergen but not saline challenge. We conclude that neurotrophins are produced endobronchially following allergen provocation, suggesting a contribution to the pathogenesis of asthma. 相似文献
43.
This paper describes an analytical procedure that has been developed to facilitate the identification of errors of commission for inclusion in a Probabilistic Safety Assessment (PSA) of a nuclear power plant operating at full power. The procedure first identifies the opportunities for error by determining when operators are required to intervene to bring the plant to a safe condition following a transient, and then identifying under what conditions this is likely to occur using a model of the causes of error. In order to make the analysis practicable, a successive screening approach is used to identify those errors with the highest potential of occurrence. The procedure has been applied as part of a PSA study, and the results of that application are summarized. For the particular plant to which the procedure was applied, the conclusion was that, because of the nature of the procedures, the high degree of redundancy in the instrumentation, the operating practices, and the control board layouts, the potential for significant errors of commission is low. 相似文献
44.
W Leonhardt C Lüthke F Leonhardt U Julius 《Computer methods and programs in biomedicine》1990,32(3-4):345-350
A microcomputer program ('EXREG') in GW BASIC was developed for fitting experimental data of A(T) to the equation A = A0 + A1.exp(-K.T) by exponential regression. In an iterative procedure K-values are tested to yield the maximum coefficient of determination. The accuracy of K is further improved in consecutive steps. The program is used to obtain the fractional turnover rate K of radiolabelled very low density lipoprotein (VLDL)-triglycerides in patients suffering from disturbances of lipid metabolism. A is the radioactivity of VLDL-triglycerides which is measured after isolation from blood. Seventeen consecutive blood samples are taken within a period of 24 h after injection of radioactive glycerol. T is the time after injection. The production rate of VLDL-triglycerides is calculated using K, the VLDL-triglyceride concentration, the body weight and height. 相似文献
45.
Balance studies designed to obtain information concerning the metabolic fate of gossypol in rats were carried out utilizing
two groups of animals. One was fed a basal diet and the other the same diet plus 500 ppm of iron as FeSO4. Single doses of 5 mg each of14C-labeled gossypol (spec. act. 19.8 μCi/mmole) were administered. The animals were maintained in metabolic cages and killed
after various periods of time. The data indicate that gossypol was poorly absorbed from the gastrointestinal tract and rapidly
eliminated from the animal body. Although the main route for gossypol elimination from the animal was by fecal excretion in
both treatments, the percentage of the total activity eliminated via the feces varied and depended on the level of iron supplied
in the diet. The results demonstrate that gossypol was least excreted via urine and that urinary excretion of radioactivity
was diminished by iron supplementation to the diet. Most of the radioactivity retained was found in the contents of different
parts of the gastrointestinal tract. Tissues, the liver, muscle, kidney and blood had the highest radioactivity, with the
liver having the highest specific activity. The data also demonstrate that addition of iron to the ration diminishes14C radioactivity in the animal body. This effect might be attributed to the formation of chelates that could not be absorbed
through the small intestine. Catalysis of the decarbonylation of gossypol by iron also appears to be a factor.
Deceased March 9, 1969. 相似文献
46.
Hypothesized that intensity and organization of muscle activity are functions of S's expectation of difficulty of a task. Task difficulty was varied for 15 20-40 yr. old instructors and undergraduates by preparing S for holding heavy and light weights, respectively. The difficult task consisted of holding a 41-lb weight following 30 sec. of holding a 19-lb weight. The easy task was holding a 6-lb weight following 30 sec. of holding the 19-lb weight. Electrical activity of the following muscles of the right (active) arm was measured: biceps brachii, brachialis, brachioradialis, flexor carpi ulnaris, and triceps. During the holding of the middle range weight, muscle activity was lower in preparation for the heavy weight than for the light weight, but there were no significant changes in the organization of muscle activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
47.
Summary The heats of reaction of phenylglycidyl ether and N,N-methylglycidylaniline as model systems for two different types of epoxy resins with primary and secondary amine were determined. In all cases the heat of reaction was found to be dependent on the ratio of the reactant components. This dependence is probably due to the formation of various complexes via a hydrogen bond. It was also found that, while the heats of reaction of phenylglycidyl ether with primary and secondary amine are the same, the heats of reaction of N,N-methylglycidylaniline with primary and secondary amine differ significantly from each other.On leave of absence from the Research Institute of Synthetic Resins and Lacquers, PardubiceThe authors thank Dr .tokrová, Dr S.Pokorný and Dr .Podzimek, Institute of Macromolecular Chemistry, Czechoslovak Academy of Sciences, Prague, for the analysis of the reaction products. 相似文献
48.
49.
Contends that all effective psychotherapeutic approaches address themselves to the human being's longing to cross the borders of the established, everyday world. This longing endangers the effectiveness and precarious security of structures that define a person and the environment. Overtly or covertly, the experience of guilt is a manifestation of this potential freedom, whereas the anxiety experienced on or beyond the borders of one's everyday world results from the threat to one's established identity. Anxiety occurs not only when the borders "hide" primitive instincts and impulses, but also when they are practical limitations of interests, talents, feelings, and actions. The psychotherapeutic exploration of guilt leads to the awareness of having avoided important potentials, as well as to the exhilarating experience of freedom. Only if the transcendental identity is sustained by the therapist's unconditional acceptance can the patient risk questioning the habitual views of self and surroundings. (2 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
50.
Marius G. Lambrechts Isak S. Pretorius Julius Marmur Paul Sollitti 《Yeast (Chichester, England)》1995,11(8):783-787
The polymorphic extracellular glucoamylase-encoding genes STA1 (chr. IV), STA2 (chr. II) and STA3 (chr. XIV), from Saccharomyces cerevisiae var. diastaticus probably evolved by genomic rearrangement of DNA regions (S1, S2 and SGA1) present in S. cerevisiae, and subsequent translocation to unlinked regions of chromosomal regions. S1, encoding a homologue to the threonine/serine-rich domain of STA glucoamylases (GAI-III), mapped to the right arm of chromosome IX. S2, encoding the hydrophobic leader peptide of GAI-III, was also mapped on the right arm of chromosome IX, next to S1, close to DAL81. The SGA1 sporulation-specific, intracellular glucoamylase-encoding gene is located on the left arm of chromosome IX, 32 kb proximal of HIS5. 相似文献