677 research outputs found

    Presynaptic Localization of Sodium/Calcium Exchangers in Neuromuscular Preparations

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    Calcium ions play a critical role in neurotransmitter release. The cytosolic Ca 2+ concentration ([Ca2+]cyt) at nerve terminals must therefore be carefully controlled. Several different mechanisms, including a plasmalemmal Na/Ca exchanger, are involved in regulating [Ca2+]cyta We employed immunofluorescence microscopy with polyclonal antiserum raised against dog cardiac sarcolemmal Na/Ca exchanger to determine the distribution of the exchanger in vertebrate neuromuscular preparations. Our data indicate that the Na/Ca exchanger is concentrated at the neuromuscular junctions of the rat diaphragm. The exchanger is also present in the nonjunctional sarcolemma, but at a much lower concentration than in the junctional regions. Denervation markedly lowers the concentration of the exchanger in the junctional regions; this implies that the Na/Ca exchanger is concentrated in the presynaptic nerve terminals. In Xenopus laevis nerve and muscle cell cocultures, high concentrations of the exchanger are observed along the neurites as well as at the nerve terminals. The high concentrations of Na/Ca exchanger at presynaptic nerve terminals in vertebrate neuromuscular preparations suggest that the exchanger may participate in the Ca-dependent regulation of neurotransmitter release. The Na/Ca exchanger is also abundant in developing neurites and growth cones, where it may also be important for Ca2+ homeostasis

    The Effect of Sulfated Glycosaminoglycans Extracted from Acanthaster planci on Full Thickness Excision Wound Healing in Animal Model

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    In this study, sulfated glycosaminoglycans (GAGs) was extracted from Acanthaster planci and its wound healing effects was assessed. Macroscopic examination revealed significant (p<0.05) contraction percentage (%) of wound on each observation (Day 1, Day 6 and Day 12) as compared to control group. Microscopic evaluations using light microscope, scanning, and transmission electron microscope showed that sulfated GAGs from A. planci enhanced epithelial cells migration and fibroblasts proliferation, and stimulate dense organisation of collagen fibers on the 12th day of observation, significantly (p<0.05) compared to control group. The microscopic study concluded that the second-intention excisional wound healing occurs faster in the GAGs treated group as compared to the saline-treated control group, while microscopical study using light microscope, scanning and transmission electron microscope revealed that the GAGs treated group have a significant effect in enhanced epithelization formation, fibroblasts proliferation and collagen fibers organization parameters as compared to the control group

    High Origin of Radial Arteries: A Report of Two Rare Cases

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    Variations in the arterial supply of the upper limb are relatively common, with reported prevalence rates ranging from 11 to 24.4%. Of these, the most commonly encountered variation in the arm is a high origin of the radial artery. However, after consecutively dissecting and examining 600 Singaporean Chinese cadavers (1,200 upper limbs), we found only two cases of this. In both cases, the brachioradial artery originated from the upper one-third of the brachial artery and continued distally as the radial artery in the forearm. The local prevalence of 0.33% of this variation is significantly lower compared against populations from other geographical regions. Although rare, recognition of the variation is of fundamental importance to clinical practice

    Discrete Roles for Impulsivity and Compulsivity in Gambling Disorder

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    Background and Objective: Complex associations between gambling disorder (GD) and impulsivity have been identified. However, little is known regarding how compulsivity associates with different impulsivity domains in GD. In this study, we examined associations between self-reported and behavioral measures of impulsivity-assessed through the Barratt Impulsiveness Scale (BIS-11) and the Experiential Discounting Task (EDT), respectively- and compulsivity-measured using the Padua Inventory and the Wisconsin Card Sorting Test (WCST), respectively-, in an adult sample with GD (N = 132, 94 men and 38 women, ages ranging from 18 to 69 years). GD severity was assessed using the South Oaks Gambling Screen. Methods: Structural Equation Modeling was used to examine relationships between impulsivity and compulsivity measures, age, and GD severity. Results: BIS-11 non-planning and BIS-11 total scores positively correlated with GD severity. The standardized coefficients for the SEM showed direct positive contributions of BIS-11 non-planning, Padua and EDT scores to GD severity. Only participants' ages directly contributed to WCST perseverative errors, and no direct or indirect effects were found with respect to GD severity. Conclusion: The findings suggest that specific aspects of impulsivity and compulsivity contribute to GD severity. Interventions specifically targeting domains that are most relevant to GD severity may improve treatment outcomes

    The heparan sulfate proteoglycan syndecan-1 regulates colon cancer stem cell function via a focal adhesion kinase—Wnt signaling axis

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    In colon cancer, downregulation of the transmembrane heparan sulfate proteoglycan syndecan‐1 (Sdc‐1) is associated with increased invasiveness, metastasis, and dedifferentiation. As Sdc‐1 modulates signaling pathways relevant to stem cell function, we tested the hypothesis that it may regulate a tumor‐initiating cell phenotype. Sdc‐1 small‐interfering RNA knockdown in the human colon cancer cell lines Caco2 and HT‐29 resulted in an increased side population (SP), enhanced aldehyde dehydrogenase 1 activity, and higher expression of CD133, LGR5, EPCAM, NANOG, SRY (sex‐determining region Y)‐box 2, KLF2, and TCF4/TCF7L2. Sdc‐1 knockdown enhanced sphere formation, cell viability, Matrigel invasiveness, and epithelial‐to‐mesenchymal transition‐related gene expression. Sdc‐1‐depleted HT‐29 xenograft growth was increased compared to controls. Decreased Sdc‐1 expression was associated with an increased activation of β1‐integrins, focal adhesion kinase (FAK), and wingless‐type (Wnt) signaling. Pharmacological FAK and Wnt inhibition blocked the enhanced stem cell phenotype and invasive growth. Sequential flow cytometric SP enrichment substantially enhanced the stem cell phenotype of Sdc‐1‐depleted cells, which showed increased resistance to doxorubicin chemotherapy and irradiation. In conclusion, Sdc‐1 depletion cooperatively enhances activation of integrins and FAK, which then generates signals for increased invasiveness and cancer stem cell properties. Our findings may provide a novel concept to target a stemness‐associated signaling axis as a therapeutic strategy to reduce metastatic spread and cancer recurrence.DatabasesThe GEO accession number of the Affymetrix transcriptomic screening is GSE58751

    A Cross-Cultural Comparison of Business Complaint Management Expectations

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    This paper is in closed access until 9th Dec 2016.Copyright © Taylor and Francis Group, LLC. This study explores the complaint management expectations of 72 British and 74 German organizational buyers using automated online means-end laddering and a Hierarchical Value Map presentation. It conceptualizes the links between expected complaint resolution attributes by the buyer (i.e., means) and the buyer's value perceptions (i.e., ends). Unlike previous research, we highlight similarities and differences in the drivers behind and attributes of complaint management expectations across two countries (Germany and the United Kingdom). Even in countries appearing to be similar economically and culturally, we find differences in the desired attributes. British buyers, for example, emphasize softer complaint resolution attributes compared to Germans. Our study is the first to present a model of complaint management expectations incorporating the role of culture, and it provides managerial directions on standardization and adaption of complaint resolution attributes. Furthermore, it evaluates justice dimensions (especially interactional justice) and their impact on perceptions of complaint management

    Measurement of the diffractive structure function in deep inelastic scattering at HERA

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    This paper presents an analysis of the inclusive properties of diffractive deep inelastic scattering events produced in epep interactions at HERA. The events are characterised by a rapidity gap between the outgoing proton system and the remaining hadronic system. Inclusive distributions are presented and compared with Monte Carlo models for diffractive processes. The data are consistent with models where the pomeron structure function has a hard and a soft contribution. The diffractive structure function is measured as a function of \xpom, the momentum fraction lost by the proton, of β\beta, the momentum fraction of the struck quark with respect to \xpom, and of Q2Q^2. The \xpom dependence is consistent with the form \xpoma where a = 1.30 ± 0.08 (stat)  0.14+ 0.08 (sys)a~=~1.30~\pm~0.08~(stat)~^{+~0.08}_{-~0.14}~(sys) in all bins of β\beta and Q2Q^2. In the measured Q2Q^2 range, the diffractive structure function approximately scales with Q2Q^2 at fixed β\beta. In an Ingelman-Schlein type model, where commonly used pomeron flux factor normalisations are assumed, it is found that the quarks within the pomeron do not saturate the momentum sum rule.Comment: 36 pages, latex, 11 figures appended as uuencoded fil

    Predictors of Occurrence and Severity of First Time Low Back Pain Episodes: Findings from a Military Inception Cohort

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    Primary prevention studies suggest that additional research on identifying risk factors predictive of low back pain (LBP) is necessary before additional interventions can be developed. In the current study we assembled a large military cohort that was initially free of LBP and followed over 2 years. The purposes of this study were to identify baseline variables from demographic, socioeconomic, general health, and psychological domains that were predictive of a) occurrence; b) time; and c) severity for first episode of self-reported LBP. Baseline and outcome measures were collected via web-based surveillance system or phone to capture monthly information over 2 years. The assembled cohort consisted of 1230 Soldiers who provided self-report data with 518 (42.1%) reporting at least one episode of LBP over 2 years. Multivariate logistic regression analysis indicated that gender, active duty status, mental and physical health scores were significant predictors of LBP. Cox regression revealed that the time to first episode of LBP was significantly shorter for Soldiers that were female, active duty, reported previous injury, and had increased BMI. Multivariate linear regression analysis investigated severity of the first episode by identifying baseline predictors of pain intensity, disability, and psychological distress. Education level and physical fitness were consistent predictors of pain intensity, while gender, smoking status, and previous injury status were predictors of disability. Gender, smoking status, physical health scores, and beliefs of back pain were consistent predictors of psychological distress. These results provide additional data to confirm the multi-factorial nature of LBP and suggest future preventative interventions focus on multi-modal approaches that target modifiable risk factors specific to the population of interest

    Observation of hard scattering in photoproduction events with a large rapidity gap at HERA

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    Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the γp\gamma p centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil
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