To evaluate whether metformin enhances leptin sensitivity, we measured leptin sensitivity after 4 weeks of metformin treatment (300 mg/kg daily) in both standard chow and high-fat-fed obese rats. Anorexic and fat-losing responses after intracerebroventricular leptin infusion for 7 days (15 g daily per rat) in standard chow rats were enhanced by metformin treatment, and these responses to leptin were attenuated in high-fat-fed obese rats compared with age-matched standard chow rats. However, these responses to leptin were corrected by metformin treatment in high-fat-fed obese rats. Moreover, serum concentrations of leptin and insulin were decreased dramatically by leptin in metformin-treated standard chow and high-fat-fed obese rats. The hypothalamic phosphorylated AMP-activated protein kinase level was decreased by lower leptin dose in metformin-treated rats than in untreated rats. In an acute study, metformin treatment also increased the anorexic effect of leptin (5 g), and this was accompanied by an increased level of phosphorylated signal transducer and activator of transcription 3 in the hypothalamus. These results suggest that metformin enhances leptin sensitivity and corrects leptin resistance in high-fat-fed obese rats and that a combination therapy including metformin and leptin would be helpful in the treatment of obesity. Diabetes 55:716 -724, 2006 L eptin, an adipocyte-derived hormone, contributes to body weight homeostasis by regulating food intake and energy expenditure (1). However, leptin is not widely used in the clinical field because obesity is accompanied by elevated serum leptin and responds poorly to the pharmacological administration of exogenous leptin, which ordinarily potently promotes fat mass loss and body weight reduction in lean subjects (2,3); moreover, this poor response of obese subjects is a characteristic of leptin resistance. Thus, the correction of leptin resistance in obese individuals would allow leptin to be used to treat obesity.Metformin, an oral biguanide insulin-sensitizing agent, inhibits hepatic glucose production, enhances the effects of insulin on glucose uptake in skeletal muscles and adipocytes, and decreases intestinal absorption of glucose (4 -7). It is also well known that metformin administration reduces body weight (8,9). Moreover, metformin decreases leptin concentration in morbidly obese subjects (9,10) and in normal-weight healthy men (11). Although leptin concentration is closely related to body fat mass, the leptin-reducing effect of metformin cannot be fully explained by body weight reduction because metformin reduces leptin level even without changing body weight in normal-weight healthy men (11). However, the mechanisms by which metformin reduces body weight and leptin concentration are poorly understood. In addition, it has been recently reported that metformin targets AMP-activated protein kinase (AMPK), which is also activated by leptin (12-14). The above findings imply that a more delicate interaction takes place between metformin and leptin. We h...
A novel method to simultaneously measure liquid solid mass transfer and external wetting efficiency was employed at column to particle ratios of 10, 6 and 3. Two prewetting procedures representing the upper (Kan) and lower (Levec) hysteresis branches were used. For a multipoint distributor on a Kan prewetted bed wetting efficiency and the specific mass transfer coefficient were almost unaffected by column diameter. The multipoint distributor on a Levec prewetted bed exhibited a decrease in specific mass transfer with decreasing column diameter. Point source experiments resulted in significantly lower wetting and mass transfer measurements with an increasing trend with respect to decreasing column diameter. The results indicate that with proper distribution and prewetting, the effect of column diameter on averaged wetting and liquid–solid mass transfer is almost negligible, a powerful result considering the importance of these parameters on reaction experiments. © 2012 Canadian Society for Chemical Engineering
Purpose: Urinary tract infection (UTI) is one of the common infectious diseases in children. Several imaging modalities can be used to confirm the presence of acute pyelonephritis (APN). Among them the 99mTcdimercaptosuccinic acid renal scan (DMSA scan) is used as a gold standard for diagnosis. Ultrasonography technology is evolving. Therefore, in this study, we investigated the sensitivity and specificity of Power Doppler ultrasonography (PDU) compared to the results from the previous study. Methods: There were 260 patients included in this study, aged between 1 and 12 months old. The patients were admitted to the Yeungnam University Medical Center between January 2008 and December 2015. All patients underwent both DMSA scan and PDU within 5days of admission. Voiding cystourethrography (VCUG) was performed in 195 patients with abnormal DMSA scan or PDU. Results: The diagnostic sensitivity of APN using PDU was 45.5% and specificity was 85.5% in 260 patients following detection of a defect on DMSA scan that was defined as APN. The diagnostic sensitivity and specificity of PDU for VUR were 65.5 % and 60.1%, respectively. The diagnostic sensitivity and specificity of DMSA scan for VUR were 95.7% and 14.1%, respectively. Conclusion: PDU has a high specificity but low sensitivity, so there are limitations in using it to replace a DMSA scan for the diagnosis of APN in children. DMSA scan and PDU have different sensitivity and specificity in diagnosis of VUR, respectively. Therefore, we suggest that the sensitivity and specificity of each test can be helpful in diagnosing APN and VUR when used in conjunction.
This paper proposes an algorithm using vibration signals and texture analysis for mechanical fault diagnosis of an induction motor. We analyze characteristics of contrast and pattern of an image converted from vibration signal and extract three texture features using gray-level co-occurrence model(GLCM). Then, the extracted features are used as inputs of a multi-level support vector machine(MLSVM) which utilizes the radial basis function(RBF) kernel function to classify each fault type. In addition, we evaluate the classification performance with varying the •제1저자 : 장원철 •교신저자 : 김종면
Borderline hypertensive rats (BHR) have been used extensively to study the interaction of environmental factors, genetics, and blood pressure. BHR are the first-generation progeny of a cross between spontaneously hypertensive rats (SHR) and control Wistar-Kyoto rats (WKR). The resting systolic blood pressure in BHR remains within the normotensive range throughout its lifetime. Interestingly, the genotype of BHR makes them particularly sensitive to the influence of environmental factors. 1)The physiological significance of the roles of GABA A in the mediation of stress-related responses is widely known. To abolish the aversive effects of behavioral stress, endogenous benzodiazepine receptor ligands have been proposed to modulate GABA transmission by activating the central-type benzodiazepine receptor (CBR) located in the GABA A receptor complex. Neuroactive steroids, the other candidate for the endogenous modulator in the ligands binding to the GABA A receptor, have been reported to show genetic differences in the behavioral sensitivities of several experimental animals.2,3) However, few studies on the stress reactivity of the CNS, especially on GABA A receptors in the BHR, have been done. Therefore, in this study, we assessed the modulatory effects of a neuroactive steroid in association with behavioral stress in BHR. MATERIALS AND METHODS AnimalsMale WKR and BHR were used. To obtain BHR, breeding pairs of female SHR and male WKR were purchased from SLC (Japan) at 10 weeks of age. Litters were culled to 8 pups at birth and weaned from their mothers at 28 d. Animals were maintained on a 12-h light/dark cycle (lights on at 06:00), housed individually, and given ad libitum access to food and water. Rats were behaviorally stressed or killed in accordance with US guidelines (NIH publication # 85-23, revised in 1985).Immobilization Stress Male rats, weighing 150-200 g, were subjected to immobilization stress as described by Nappi and Rivest. 4) Briefly, the stress was produced by forcing the rats into immobilizer (Centrap cage, Fischer, Pittsburg, PA, U.S.A.) for 2 h (14:00-16:00) for 2 weeks. The animals were decapitated after termination of immobilization stress.Receptor-Binding Assay For the measurement of the modulatory effect of pregnanolone on [ 3 H]flunitrazepam binding to the CBR, the cerebral cortex of rats (male, 250-350 g) was removed immediately after decapitation. Tissues were disrupted in 50 volumes of 50 mM Tris-citrate buffer (pH 7.4) and centrifuged at 20000 g for 20 min, and the pellets were resuspended in 50 volumes of 50 mM Tris-citrate buffer (pH 7.4) and recentrifuged. Final pellets were stored for assay at Ϫ70°C after 3-5 washing procedures. The binding of [ 3 H]flunitrazepam (85.0 Ci/mmol, NEN), an agonist of the CBR, to the membranes was assayed using a filtration technique. Each assay comprised triplicate samples containig 0.16 mg of protein suspended in 0.5 ml of 50 mM Triscitrate buffer (pH 7.4) incubated for 60 min at 4°C using 1 nM of radiolabeled drugs. Nonspecific binding was determine...
With the development of IT technologies, IT environment is making great change over life whole and is displacing business and business achievement systems of industry at the fast speed. Software development using project management tool is more important because of constructing the consistent and reliable system. So, design and implementation of the project management tool which support data standardization of project is proposed in this paper.
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