1,268 research outputs found
Role of fat hydrolysis in regulating glucagon-like Peptide-1 secretion
No full textContext: Glucagon-like peptide-1 (GLP-1) is produced by specialized cells in the gut and secreted in response to carbohydrates and lipids. The mechanisms regulating fat-stimulated GLP-1 release have, however, not been clarified in detail. Aim: We aimed to investigate the effect of intraduodenal (ID) fat hydrolysis on GLP-1 release and test whether the signal is mediated through cholecystokinin (CCK)-1 receptors. Design and Setting: Thirty-four healthy, male ambulatory volunteers were studied in three consecutive, randomized, double blind, crossover studies. Intervention: There were three interventions: 1) 12 subjects received an ID fat infusion with or without orlistat, an irreversible inhibitor of gastrointestinal lipases, in comparison with vehicle; 2) 12 subjects received ID sodium oleate (C18:1), ID sodium caprylate (C8:0), or ID vehicle; and 3) 10 subjects received ID sodium oleate with and without the CCK-1 receptor antagonist dexloxiglumide or ID vehicle plus iv saline (placebo). The effect of these treatments on GLP-1 concentrations and CCK release was quantified. Results: The following results were reached: 1) ID fat induced significant increase in GLP-1 concentrations (P > 0.004), and inhibition of fat hydrolysis by orlistat abolished this effect; 2) sodium oleate significantly stimulated GLP-1 release (P > 0.008), whereas sodium caprylate was ineffective compared with controls; and 3) dexloxiglumide administration abolished the effect of sodium oleate on GLP-1. ID fat or sodium oleate significantly stimulated plasma CCK (P > 0.006 and P > 0.004) compared with saline, whereas sodium caprylate did not. Conclusion: Generation of long-chain fatty acids through hydrolysis of fat is a critical step for fat-induced stimulation of GLP-1 in humans; the signal is mediated via CCK release and CCK-1 receptors
Evaluation of management factors affecting the relative success of a Brook Trout eradication program using YY male fish and electrofishing suppression
No full textRemoval of non-native fish populations can be crucial to the conservation of native species, but often presents a complex challenge for managers. The goal of Trojan Y chromosome (TYC) programs is to skew the non-native sex ratio until only males remain, leading to eradication. We present results from a simulation model used to explore effects of alternative management approaches on an in-progress mechanical removal and TYC program to eradicate non-native Brook Trout. Simulation results indicated that stocking fingerling YY males (~137 mm) was more effective than stocking catchable-sized YY males (~230 mm), although questions about inter-cohort competition warrant further investigation. Increasing the proportion of mature fingerling YY males reduced treatment time by increasing the number of YY male spawners and increasing density-dependent mortality on young, mature wild Brook Trout. Maximizing the spatial distribution of YY male releases may be crucial to program success but is also dependent upon immediate dispersal movements. Principles derived from our results can be broadly applied to the management of other aquatic invaded systems using TYC programs to eradicate non-native species.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Pituitary adenylate cyclase activating polypeptide stimulates release of peptide YY
No full text The purpose of these experiments was to examine the effects of the recently discovered gastrointestinal peptide, pituitary adenylate cyclase activating polypeptide (PACAP), and two structurally related peptides, vasoactive intestinal polypeptide and secretin, on release of peptide YY (PYY) in conscious dogs. Intravenous administration of PACAP-27 or -38 stimulated a dose-related release of PYY; PACAP-27 was more potent than PACAP-38. PACAP-stimulated release of PYY was inhibited significantly by atropine, whereas ganglionic or beta-adrenergic blockade with hexamethonium and propranolol treatment, respectively, did not affect PACAP-induced release of PYY significantly (P > 0.05). These results indicate that PACAP-induced release of PYY is cholinergic dependent and that beta-adrenergic tone and ganglionic transmission do not participate in PACAP-induced release of PYY. PACAP may play a role in the neural regulation of PYY release. </jats:p
Wheat gluten hydrolysate potently stimulates peptide-YY secretion and suppresses food intake in rats
No full textThe study was aimed to compare the satiating effect of various protein hydrolysates in rats and examine the underlying mechanism associated with the satiety hormones. Food intake and portal satiety hormone levels were measured in rats. Enteroendocrine cell-lines were employed to study the direct effect of protein hydrolysates on gut hormone secretions. The results showed that oral preload of wheat gluten hydrolysate (WGH) suppressed food intake greater and longer than other hydrolysates. The portal peptide-YY levels in WGH-treated rats at 2 h and 3 h were higher than those in control- and lactalbumin hydrolysate (LAH)-treated rats. In a distal enteroendocrine cell model, WGH more potently stimulated glucagon-like peptide-1 secretion than LAH, and the effect was largely enhanced by pepsin/pancreatin digestion of WGH. These results suggest WGH is potent in activating enteroendocrine cells to release satiety hormones leading to the prolonged suppression of food intake
Block TERM factorization of block matrices
No full textReversible integer mapping (or integer transform) is a useful way to realize lossless coding, and this technique has been used for multi-component image compression in the new international image compression standard JPEG 2000. For any nonsingular linear transform of finite dimension, its integer transform can be implemented by factorizing the transform matrix into 3 triangular elementary reversible matrices (TERMs) or a series of single-row elementary reversible matrices (SERMs). To speed up and parallelize integer transforms, we study block TERM and SERM factorizations in this paper. First, to guarantee flexible scaling manners, the classical determinant (det) is generalized to a matrix function, DET, which is shown to have many important properties analogous to those of det. Then based on DET, a generic block TERM factorization, BLUS, is presented for any nonsingular block matrix. Our conclusions can cover the early optimal point factorizations and provide an efficient way to implement integer transforms for large matrices.Computer Science, Information SystemsSCI(E)3ARTICLE4421-4364
Local estimate on singular solution to scalar curvature equation
No full textAbstractIn this paper, we study the local behavior of a positive singular solution u near its singular points of the following equation: Δu(x)+d(x,Z)2Nun+2n−2=0inΩ⧹Z,u(x)>0andu∈C2inΩ⧹Z, where N is a positive integer, Ω is a bounded open domain in Rn, Z is a finite set of points, and d(x,Z) denotes the distance between x and Z
A Multivariate Surface-Based Analysis of the Putamen in Premature Newborns: Regional Differences within the Ventral Striatum
No full textMany children born preterm exhibit frontal executive dysfunction, behavioral problems including attentional deficit/hyperactivity disorder and attention related learning disabilities. Anomalies in regional specificity of cortico-striato-thalamo-cortical circuits may underlie deficits in these disorders. Nonspecific volumetric deficits of striatal structures have been documented in these subjects, but little is known about surface deformation in these structures. For the first time, here we found regional surface morphological differences in the preterm neonatal ventral striatum. We performed regional group comparisons of the surface anatomy of the striatum (putamen and globus pallidus) between 17 preterm and 19 term-born neonates at term-equivalent age. We reconstructed striatal surfaces from manually segmented brain magnetic resonance images and analyzed them using our in-house conformal mapping program. All surfaces were registered to a template with a new surface fluid registration method. Vertex-based statistical comparisons between the two groups were performed via four methods: univariate and multivariate tensor-based morphometry, the commonly used medial axis distance, and a combination of the last two statistics. We found statistically significant differences in regional morphology between the two groups that are consistent across statistics, but more extensive for multivariate measures. Differences were localized to the ventral aspect of the striatum. In particular, we found abnormalities in the preterm anterior/inferior putamen, which is interconnected with the medial orbital/prefrontal cortex and the midline thalamic nuclei including the medial dorsal nucleus and pulvinar. These findings support the hypothesis that the ventral striatum is vulnerable, within the cortico-stiato-thalamo-cortical neural circuitry, which may underlie the risk for long-term development of frontal executive dysfunction, attention deficit hyperactivity disorder and attention-related learning disabilities in preterm neonates. © 2013 Shi et al
Evaluation and analysis of impact of subsidies on small scale renewable energy technologies dissemination: a case study of Nepal
No full textThe report has analysed the status of rural electrification using renewable energy technologies (RETs) and the current subsidy delivery modality of RETs in Nepal. As the Government of Nepal is subsidizing small scale renewable energy projects, it is important to evaluate and analyse the programme to make sure that a programme is running in an effective and efficient way while reaching the target group.
During the course of the research, primary information collected from the field has been compiled using appropriate tools/software (such as MS Office) and analyzed. Different sets of questionnaires were prepared, targeting different personnel ranging from the users’ level to the government policy level. The field survey methods include field observations of RETs installations and operations along with interviews with selected users on a random sampling basis to identify barriers to subsidy delivery and possible measures to overcome these barriers; to determine user satisfaction level and time period for subsidy delivery mechanisms.
The report started with the country background information and the rationale behind the study. This is followed by the literature review and information on the current status of small scale RETs in the country. Next it deals with the organizational structure and current subsidy delivery modality of RETs in the country. The evaluation of the effectiveness of the subsidy with the current subsidy delivery modality has been analyzed based on six parameters; Targets and Achievements, Impact of RETs, Subsidy Delivery System Efficiency, Transparency, Sustainability and Effectiveness.
The research shows that the subsidized government program has been successful in achieving its goal to provide basic energy services in rural areas through RETs in terms of its quantitative target. Although the subsidized program is successful in electrifying the rural communities via RETs, the poorest of the poor families are still excluded from the subsidy. The program seems to benefit more the rich and upper middle class families rather than the poor families for which the subsidy was intended. The high capital cost and long subsidy delivery process are the main important reasons for this failure. The author has proposed a new modality which might overcome the time barriers and bureaucratic process in the subsidy delivery mechanism and will decrease the lead time. This will in turn help to reduce the operational cost of the private companies and will encourage more players to enter the market, increase competition and result in lower system costs.
After identifying gaps in the current subsidy delivery modality, the project report ends with the recommendation of a new modality improving the current modality and filling the gaps identified. As this study has some limitations, as described in chapter one, the scope of further works has been listed at the end
Inhibitory action of peptide YY on gastric acid secretion
No full text The purpose of this study is to investigate the effect of peptide YY (PYY) on pentagastrin-, histamine-, and bethanechol-stimulated gastric acid secretion and the possible mechanisms by which PYY inhibits gastric acid secretion. Six mongrel dogs with chronic gastric and duodenal fistulas were given an intravenous infusion of pentagastrin (0.5 microgram . kg-1 . h-1), histamine (18 micrograms . kg-1 . h-1), or bethanechol (80 micrograms . kg-1 . h-1) either alone or simultaneously with intravenous PYY (100, 200, 400, pmol . kg-1 . h-1). PYY (100, 200, 400 pmol . kg-1 . h-1) inhibited pentagastrin-stimulated gastric acid secretion in a dose-dependent manner. PYY (400 pmol . kg-1 . h-1) did not depress bethanechol-stimulated gastric acid secretion. PYY (400 pmol . kg-1 . h-1) also failed to inhibit histamine-stimulated gastric acid secretion. Furthermore, PYY inhibit pentagastrin-stimulated gastric acid secretion in the face of atropine, vagotomy, or indomethacin treatment. These findings indicate that the inhibitory action of PYY on gastric acid secretion is in part independent of long and short cholinergic pathways. These findings also indicate that the inhibitory mechanism of PYY is independent of prostaglandin synthesis. Our findings are discussed in relation to previous reports regarding the effects of PYY on gastric acid secretion. </jats:p
Growth hormone upregulates gastrin and peptide YY gene expression
No full textThe purpose of these studies was to examine the effects of excess growth hormone (GH) on gastrin and peptide YY (PYY) gene expression. Transgenic mice with the bovine GH gene linked to a mouse metallothionein I promoter were used as a model of chronic GH excess. Antral gastrin mRNA and peptide levels were elevated significantly (P < 0.05) in GH transgenic mice compared with wild type littermates. Ileal PYY mRNA and ileal and colonic PYY levels were significantly elevated in GH transgenic mice compared with wild type littermates. The elevations in gastrin and PYY gene expression in GH transgenic mice were independent of food intake. Serum concentrations of gastrin and PYY were also elevated in GH transgenic mice. Immunohistochemical analysis showed that the density of PYY-containing cells in the colon of GH transgenic mice and wild type littermates did not differ. In addition, the mRNA and protein levels of chromogranin A, a marker of endocrine cells, were not increased in the colon of GH transgenic mice. Together, these data indicate that GH, insulin-like growth factor I, or both can upregulate gastrointestinal gastrin and PYY gene expression directly.</jats:p
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