218 research outputs found

    Real-world context, interest, understanding, and retention

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    This study investigated the use of real-world contexts during instruction in a high school physics class - through building file folder bridges- and the resulting effect upon student interest in the subject matter, level of understanding, and degree of retention. In particular, the study focused upon whether increases in student interest were attained through the use of real-world contexts, and if the elevated interest level led to a higher degree of subject matter understanding than would be achieved using more traditional teaching methods. The study also determined whether using real-world contexts ultimately resulted in achievement of greater levels of knowledge retention by students. Class observations during traditionally taught units and during units that incorporated real-world contexts, along with a post-graduation questionnaire, were used to assess differences in student interest levels. Student pre- and post-unit test scores were evaluated and compared to determine if statistical differences existed in levels of understanding resulting from the different teaching methods. The post-graduation questionnaire results provided evidence of retention that could be related back to teaching methods. The results of this study revealed the importance of incorporating real-world contexts into science and mathematics courses. Students better understood the relevance of the lessons, which led to higher levels of interest and greater understanding than was achieved through more traditional teaching methods. The use of real-world contexts improved knowledge retention

    Reframing perceptions: A phenomenological inquiry into students’ written reflections on learning about mindfulness

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    Introduction Mindfulness practices offer approaches to reflection that have been argued to contribute to positive outcomes for students in the health professions. Despite calls for more phenomenological investigations in the field, few studies examine the lived experience of learning about mindfulness in professional schools.  Objective The objective of this study was to inquire into first-hand written accounts of students’ experiences of learning about mindfulness.  Methods This study reports on occupational therapy health professions students’ phenomenological reflections written during and following a 5 week, 15 hour, mindfulness elective course offered at a Canadian University. The study adopts a hermeneutic phenomenological methodology and is informed by theoretical frameworks of embodiment and practice theories. An indepth thematic analysis of twenty-one students' written reflections on the experience of integrating mindfulness practices into their lives was undertaken.  Results Predominant themes identified in students’ written reflections include: reframing perceptions, ‘being’ while ‘doing’, witnessing the struggle, and compassion for self and others.  Conclusions This research contributes richly textured accounts that advance understandings about the affordances of mindfulness education in the lives of future health care practitioners. The results also hold implications for educational design in higher education professional school contexts, considerations of mindfulness practices in future professional practitioners’ everyday and workplace occupations, and identification of promising avenues for future research. This study is funded by the Social Science and Humanities Research Council of Canada (SSHRC).&nbsp

    MAP kinases bind endothelial nitric oxide synthase

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    AbstractEndothelial nitric oxide synthase (eNOS) contains a motif similar to recognition sequences in known MAPK binding partners. In optical biosensing experiments, eNOS bound p38 and ERK with ∼100nM affinity and complex kinetics. Binding is diffusion-limited (kon∼.15×106M−1s−1). Neuronal NOS also bound p38 but exhibited much slower and weaker binding. p38-eNOS binding was inhibited by calmodulin. Evidence for a ternary complex was found when eNOS bound p38 was exposed to CaM, increasing the apparent dissociation rate. These observations strongly suggest a direct role for MAPK in regulation of NOS with implications for signaling pathways including angiogenesis and control of vascular tone

    Inhibition of Glutathione Peroxidase

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    Glutathione peroxidase (GPx) is an intracellular antioxidant enzyme that mediates the amount of hydrogen peroxide present in cells. Through this activity, GPx aids in the regulation of cellular processes that use hydrogen peroxide, including growth and proliferation. It may be desirable to inhibit GPx in certain diseased states, e.g. cancer, where GPx is over expressed. The Tapu lab is making N-heterocyclic compounds that have shown efficiency inhibiting thioredoxin reductase, which is another selenocysteine containing enzyme. Our aim is to test similar compounds to see if they have the ability to inhibit GPx. In order to test these compounds, we have to be able to assay the activity of GPx. I will present my work developing the GPx assay so that we can test the. N-heterocyclic compounds from the Tapu laboratory. The GPx assay is coupled to glutathione reductase (GRase). Since oxidized glutathione is a product of the GPx assay, we can monitor GPx activity through the oxidation of NADPH by GRase and use this to test inhibition by the Tapu lab compounds

    Endothelial Nitric Oxide Synthase is Regulated by ERK Phosphorylation at Ser602

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    eNOS (endothelial nitric oxide synthase) contains a MAPK (mitogen-activated protein kinase)-binding site associated with a major eNOS control element. Purified ERK (extracellular-signal-regulated kinase) phosphorylates eNOS with a stoichiometry of 2–3 phosphates per eNOS monomer. Phosphorylation decreases NO synthesis and cytochrome c reductase activity. Three sites of phosphorylation were detected by MS. All sites matched the SP and TP MAPK (mitogen-activated protein kinase) phosphorylation motif. Ser602 lies at the N-terminal edge of the 42-residue eNOS AI (autoinhibitory) element. The pentabasic MAPK-binding site lies at the opposite end of the AI, and other critical regulatory features are between them. Thr46 and Ser58 are located in a flexible region associated with the N terminus of the oxygenase domain. In contrast with PKC (protein kinase C), phosphorylation by ERK did not significantly interfere with CaM (calmodulin) binding as analysed by optical biosensing. Instead, ERK phosphorylation favours a state in which FMN and FAD are in close association and prevents conformational changes that expose reduced FMN to acceptors. The close associations between control sites in a few regions of the molecule suggest that control of signal generation is modulated by multiple inputs interacting directly on the surface of eNOS via overlapping binding domains and tightly grouped targets

    Glutaredoxin-1 up-regulation induces soluble vascular endothelial growth factor receptor 1, attenuating post-ischemia limb revascularization

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    Glutaredoxin-1 (Glrx) is a cytosolic enzyme that regulates diverse cellular function by removal of GSH adducts from S-glutathionylated proteins including signaling molecules and transcription factors. Glrx is up-regulated during inflammation and diabetes. Glrx overexpression inhibits VEGF-induced endothelial cell (EC) migration. The aim was to investigate the role of up-regulated Glrx in EC angiogenic capacities and in vivo revascularization in the setting of hind limb ischemia. Glrx overexpressing EC from Glrx transgenic mice (TG) showed impaired migration and network formation and secreted higher level of soluble VEGF receptor 1 (sFlt), an antagonizing factor to VEGF. After hind limb ischemia surgery Glrx TG mice demonstrated impaired blood flow recovery, associated with lower capillary density and poorer limb motor function compared to wild type littermates. There were also higher levels of anti-angiogenic sFlt expression in the muscle and plasma of Glrx TG mice after surgery. Non-canonical Wnt5a is known to induce sFlt. Wnt5a was highly expressed in ischemic muscles and EC from Glrx TG mice, and exogenous Wnt5a induced sFlt expression and inhibited network formation in human microvascular EC. Adenoviral Glrx-induced sFlt in EC was inhibited by a competitive Wnt5a inhibitor. Furthermore, Glrx overexpression removed GSH adducts on p65 in ischemic muscle and EC, and enhanced nuclear factor kappa B (NF-kB) activity which was responsible for Wnt5a-sFlt induction. Taken together, up-regulated Glrx induces sFlt in EC via NF-kB -dependent Wnt5a, resulting in attenuated revascularization in hind limb ischemia. The Glrx-induced sFlt may be a part of mechanism of redox regulated VEGF signaling

    Comparative analysis of glutaredoxin domains from bacterial opportunistic pathogens

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    NMR structures of the glutaredoxin (GLXR) domains from Br. melitensis and Ba. henselae have been determined as part of the SSGCID initiative. Comparison of the domains with known structures reveals overall structural similarity between these proteins and previously determined E. coli GLXR structures, with minor changes associated with the position of helix 1 and with regions that diverge from similar structures found in the closest related human homolog

    The RNA-Binding Protein KSRP Promotes Decay of β-Catenin mRNA and Is Inactivated by PI3K-AKT Signaling

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    β-catenin plays an essential role in several biological events including cell fate determination, cell proliferation, and transformation. Here we report that β-catenin is encoded by a labile transcript whose half-life is prolonged by Wnt and phosphatidylinositol 3-kinase–AKT signaling. AKT phosphorylates the mRNA decay-promoting factor KSRP at a unique serine residue, induces its association with the multifunctional protein 14-3-3, and prevents KSRP interaction with the exoribonucleolytic complex exosome. This impairs KSRP's ability to promote rapid mRNA decay. Our results uncover an unanticipated level of control of β-catenin expression pointing to KSRP as a required factor to ensure rapid degradation of β-catenin in unstimulated cells. We propose KSRP phosphorylation as a link between phosphatidylinositol 3-kinase–AKT signaling and β-catenin accumulation

    Not1 mediates recruitment of the deadenylase Caf1 to mRNAs targeted for degradation by tristetraprolin

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    The carbon catabolite repressor protein 4 (Ccr4)–Negative on TATA (Not) complex controls gene expression at two levels. In the nucleus, it regulates the basal transcription machinery, nuclear receptor-mediated transcription and histone modifications. In the cytoplasm, the complex is required for messenger RNA (mRNA) turnover through its two associated deadenylases, Ccr4 and Caf1. Not1 is the largest protein of the Ccr4–Not complex and serves as a scaffold for other subunits of the complex. Here, we provide evidence that human Not1 in the cytoplasm associates with the C-terminal domain of tristetraprolin (TTP), an RNA binding protein that mediates rapid degradation of mRNAs containing AU-rich elements (AREs). Not1 shows extensive interaction through its central region with TTP, whereas binding of Caf1 is restricted to a smaller central domain within Not1. Importantly, Not1 is required for the rapid decay of ARE-mRNAs, and TTP can recruit the Caf1 deadenylase only in presence of Not1. Thus, cytoplasmic Not1 provides a platform that allows a specific RNA binding protein to recruit the Caf1 deadenylase and thereby trigger decay of its target mRNAs
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