659 research outputs found

    До питання про культурну атрибутацію шару ранньозалізного віку на городищі Теребовля І

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    У статті на основі досліджень І.Русанової, Р.Миська та М.Ягодинської проведено атрибутацію культурного шару ранньозалізного віку на городищі літописної Теребовлі. Висловлюється припущення, що перші оборонні споруди на городищі Теребовля І «Замкова Гора», вал 3-ій та 4-ий городища збудовані носіями висоцької культури у ІХ-VIII ст. до н.е

    Novel method for detection of glycogen in cells

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    Glycogen, a branched polymer of glucose, functions as an energy reserve in many living organisms. Abnormalities in glycogen metabolism, usually excessive accumulation, can be caused genetically, most often through mutation of the enzymes directly involved in synthesis and degradation of the polymer leading to a variety of glycogen storage diseases (GSDs). Microscopic visualization of glycogen deposits in cells and tissues is important for the study of normal glycogen metabolism as well as diagnosis of GSDs. Here, we describe a method for the detection of glycogen using a renewable, recombinant protein which contains the carbohydrate-binding module (CBM) from starch-binding domain containing protein 1 (Stbd1). We generated a fusion protein containing g lutathione S-transferase, a cM c eptitope and the tbd1 BM (GYSC) for use as a glycogen-binding probe, which can be detected with secondary antibodies against glutathione S-transferase or cMyc. By enzyme-linked immunosorbent assay, we demonstrate that GYSC binds glycogen and two other polymers of glucose, amylopectin and amylose. Immunofluorescence staining of cultured cells indicate a GYSC-specific signal that is co-localized with signals obtained with anti-glycogen or anti-glycogen synthase antibodies. GYSC-positive staining inside of lysosomes is observed in individual muscle fibers isolated from mice deficient in lysosomal enzyme acid alpha-glucosidase, a well-characterized model of GSD II (Pompe disease). Co-localized GYSC and glycogen signals are also found in muscle fibers isolated from mice deficient in malin, a model for Lafora disease. These data indicate that GYSC is a novel probe that can be used to study glycogen metabolism under normal and pathological conditions

    Taking stock of organization and performance in the public sector

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    To deepen our understanding of the publicness-performance relationship, the paper combines and integrates two conceptual models. This qualitative research seeks to cast light on two categories of organizational variables that act as performance moderators, i.e., agency-level factors and individual-level factors, by selectively reviewing academic studies on the performance of public services. It then discusses the implications of the extended model developed by the authors and suggests future research trajectorie

    Muscle glycogen remodeling and glycogen phosphate metabolism following exhaustive exercise of wild type and laforin knockout mice

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    Glycogen, the repository of glucose in many cell types, contains small amounts of covalent phosphate, of uncertain function and poorly understood metabolism. Loss-of-function mutations in the laforin gene cause the fatal neurodegenerative disorder, Lafora disease, characterized by increased glycogen phosphorylation and the formation of abnormal deposits of glycogen-like material called Lafora bodies. It is generally accepted that the phosphate is removed by the laforin phosphatase. To study the dynamics of skeletal muscle glycogen phosphorylation in vivo under physiological conditions, mice were subjected to glycogen-depleting exercise and then monitored while they resynthesized glycogen. Depletion of glycogen by exercise was associated with a substantial reduction in total glycogen phosphate and the newly resynthesized glycogen was less branched and less phosphorylated. Branching returned to normal on a time frame of days, whereas phosphorylation remained suppressed over a longer period of time. We observed no change in markers of autophagy. Exercise of 3-month-old laforin knock-out mice caused a similar depletion of glycogen but no loss of glycogen phosphate. Furthermore, remodeling of glycogen to restore the basal branching pattern was delayed in the knock-out animals. From these results, we infer that 1) laforin is responsible for glycogen dephosphorylation during exercise and acts during the cytosolic degradation of glycogen, 2) excess glycogen phosphorylation in the absence of laforin delays the normal remodeling of the branching structure, and 3) the accumulation of glycogen phosphate is a relatively slow process involving multiple cycles of glycogen synthesis-degradation, consistent with the slow onset of the symptoms of Lafora disease

    Lack of liver glycogen causes hepatic insulin resistance and steatosis in mice

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    Disruption of the Gys2 gene encoding the liver isoform of glycogen synthase generates a mouse strain (LGSKO) that almost completely lacks hepatic glycogen, has impaired glucose disposal, and is pre-disposed to entering the fasted state. This study investigated how the lack of liver glycogen increases fat accumulation and the development of liver insulin resistance. Insulin signaling in LGSKO mice was reduced in liver, but not muscle, suggesting an organ-specific defect. Phosphorylation of components of the hepatic insulin-signaling pathway, namely IRS1, Akt, and GSK3, was decreased in LGSKO mice. Moreover, insulin stimulation of their phosphorylation was significantly suppressed, both temporally and in an insulin dose response. Phosphorylation of the insulin-regulated transcription factor FoxO1 was somewhat reduced and insulin treatment did not elicit normal translocation of FoxO1 out of the nucleus. Fat overaccumulated in LGSKO livers, showing an aberrant distribution in the acinus, an increase not explained by a reduction in hepatic triglyceride export. Rather, when administered orally to fasted mice, glucose was directed toward hepatic lipogenesis as judged by the activity, protein levels, and expression of several fatty acid synthesis genes, namely, acetyl-CoA carboxylase, fatty acid synthase, SREBP1c, chREBP, glucokinase, and pyruvate kinase. Furthermore, using cultured primary hepatocytes, we found that lipogenesis was increased by 40% in LGSKO cells compared with controls. Of note, the hepatic insulin resistance was not associated with increased levels of pro-inflammatory markers. Our results suggest that loss of liver glycogen synthesis diverts glucose toward fat synthesis, correlating with impaired hepatic insulin signaling and glucose disposal

    Design and Methods for a Comparative Effectiveness Pilot Study: Virtual World vs. Face-to-Face Diabetes Self-Management

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    BACKGROUND: Type 2 diabetes (diabetes) is a serious threat to public health in the United States and disproportionally affects many racial/ethnic minority groups, including African Americans. Limited access to treatment and high attrition rates further contribute to health disparities in diabetes-related morbidity and mortality among minorities. Greater opportunities for increasing access and decreasing barriers to treatment are needed. Technology-based interventions have potential for accomplishing this goal but evidence of feasibility and potential effectiveness is lacking, especially for populations that traditionally have limited educational attainment and low computer literacy. OBJECTIVE: This paper describes the design and methods of a pilot randomized clinical trial that will compare the feasibility and potential efficacy of delivering a diabetes self-management intervention via a virtual world vs. a face-to-face format. METHODS: Study participants (n=100) will be African American women with uncontrolled type 2 diabetes recruited from primary care practices and affiliated health centers at a large safety net hospital in Massachusetts. Participants will be randomized into a virtual world-based (VW) intervention condition or a face-to-face control condition. Both conditions provide the same theory-based curriculum and equivalent exposure to the self-management program (eight group sessions), and both will be delivered by a single intervention team (a dietitian and a diabetes educator). Assessments will be conducted at baseline and 4 months. Feasibility will be determined by evaluating the degree to which participants engage in the VW-based intervention compared to face to face (number of sessions completed). Potential efficacy will be determined by comparing change in physiological (glycemic control) and behavioral (self-reported dietary intake, physical activity, blood glucose self-monitoring, and medication adherence) outcomes between the experimental and control groups. RESULTS: The primary outcomes of interest are feasibility of the VW intervention and its potential efficacy on glucose control and diabetes self-management behaviors, compared to the face-to-face condition. Analysis will use a two-sample Kolmogorov-Smirnov test for changes in variable distribution. P values will be calculated using binomial tests for proportions and t tests for continuous variables. CONCLUSIONS: If the intervention is found to be feasible and promising, it will be tested in a larger RCT

    2015 Building a Grad Nation Report: Progress and Challenge in Ending the High School Dropout Epidemic

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    This sixth annual report to the nation highlights the significant progress that has been made, but also the serious challenges that remain – closing gaping graduation gaps between various student populations; tackling the challenge in key states and school districts; and keeping the nation's focus on ensuring that all students – whom Robert Putnam calls "our kids" – have an equal chance at the American Drea

    Glycogen Phosphomonoester Distribution in Mouse Models of the Progressive Myoclonic Epilepsy, Lafora Disease

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    Glycogen is a branched polymer of glucose that acts as an energy reserve in many cell types. Glycogen contains trace amounts of covalent phosphate, in the range of 1 phosphate per 500–2000 glucose residues depending on the source. The function, if any, is unknown, but in at least one genetic disease, the progressive myoclonic epilepsy Lafora disease, excessive phosphorylation of glycogen has been implicated in the pathology by disturbing glycogen structure. Some 90% of Lafora cases are attributed to mutations of the EPM2A or EPM2B genes, and mice with either gene disrupted accumulate hyperphosphorylated glycogen. It is, therefore, of importance to understand the chemistry of glycogen phosphorylation. Rabbit skeletal muscle glycogen contained covalent phosphate as monoesters of C2, C3, and C6 carbons of glucose residues based on analyses of phospho-oligosaccharides by NMR. Furthermore, using a sensitive assay for glucose 6-P in hydrolysates of glycogen coupled with measurement of total phosphate, we determined the proportion of C6 phosphorylation in rabbit muscle glycogen to be ∼20%. C6 phosphorylation also accounted for ∼20% of the covalent phosphate in wild type mouse muscle glycogen. Glycogen phosphorylation in Epm2a−/− and Epm2b−/− mice was increased 8- and 4-fold compared with wild type mice, but the proportion of C6 phosphorylation remained unchanged at ∼20%. Therefore, our results suggest that C2, C3, and/or C6 phosphate could all contribute to abnormal glycogen structure or to Lafora disease

    Incorporation of phosphate into glycogen by glycogen synthase

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    The storage polymer glycogen normally contains small amounts of covalently attached phosphate as phosphomonoesters at C2, C3 and C6 atoms of glucose residues. In the absence of the laforin phosphatase, as in the rare childhood epilepsy Lafora disease, the phosphorylation level is elevated and is associated with abnormal glycogen structure that contributes to the pathology. Laforin therefore likely functions in vivo as a glycogen phosphatase. The mechanism of glycogen phosphorylation is less well-understood. We have reported that glycogen synthase incorporates phosphate into glycogen via a rare side reaction in which glucose-phosphate rather than glucose is transferred to a growing polyglucose chain (Tagliabracci et al. (2011) Cell Metab13, 274-282). We proposed a mechanism to account for phosphorylation at C2 and possibly at C3. Our results have since been challenged (Nitschke et al. (2013) Cell Metab17, 756-767). Here we extend the evidence supporting our conclusion, validating the assay used for the detection of glycogen phosphorylation, measurement of the transfer of (32)P from [β-(32)P]UDP-glucose to glycogen by glycogen synthase. The (32)P associated with the glycogen fraction was stable to ethanol precipitation, SDS-PAGE and gel filtration on Sephadex G50. The (32)P-signal was not affected by inclusion of excess unlabeled UDP before analysis or by treatment with a UDPase, arguing against the signal being due to contaminating [β-(32)P]UDP generated in the reaction. Furthermore, [(32)P]UDP did not bind non-covalently to glycogen. The (32)P associated with glycogen was released by laforin treatment, suggesting that it was present as a phosphomonoester. The conclusion is that glycogen synthase can mediate the introduction of phosphate into glycogen, thereby providing a possible mechanism for C2, and perhaps C3, phosphorylation
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