431 research outputs found

    Using Physical Chemistry To Differentiate Nicotinic from Cholinergic Agonists at the Nicotinic Acetylcholine Receptor

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    The binding of three distinct agonists - acetylcholine (ACh), nicotine, and epibatidine - to the nicotinic acetylcholine receptor has been probed using unnatural amino acid mutagenesis. ACh makes a cation−π interaction with Trp α149, while nicotine employs a hydrogen bond to a backbone carbonyl in the same region of the agonist binding site. The nicotine analogue epibatidine achieves its high potency by taking advantage of both the cation−π interaction and the backbone hydrogen bond. A simple structural model that considers only possible interactions with Trp α149 suggests that a novel aromatic C - H···O=C hydrogen bond further augments the binding of epibatidine. These studies illustrate the subtleties and complexities of the interactions between drugs and membrane receptors and establish a paradigm for obtaining detailed structural information

    Chemical-Scale Studies on the Role of a Conserved Aspartate in Preorganizing the Agonist Binding Site of the Nicotinic Acetylcholine Receptor

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    The nicotinic acetylcholine receptor and related Cys-loop receptors are ligand-gated ion channels that mediate fast synaptic transmission throughout the central and peripheral nervous system. A highly conserved aspartate residue (D89) that is near the agonist binding site but does not directly contact the ligand plays a critical part in receptor function. Here we probe the role of D89 using unnatural amino acid mutagenesis coupled with electrophysiology. Homology modeling implicates several hydrogen bonds involving D89. We find that no single hydrogen bond is essential to proper receptor function. Apparently, the side chain of D89 establishes a redundant network of hydrogen bonds; these bonds preorganize the agonist binding site by positioning a critical tryptophan residue that directly contacts the ligand. Earlier studies of the D89N mutant led to the proposal that a negative charge at this position is essential for receptor function. However, we find that receptors with neutral side chains at position 89 can function well, if the side chain is less perturbing than the amide of asparagine (nitro or keto groups allow function) or if a compensating backbone mutation is introduced to relieve unfavorable electrostatics

    Visual analysis of global comparative mapping of the practice domains of the nurse practitioner/advanced practice nursing role in respondent countries.

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    Internationally, there is increasing demand for nurse practitioner (NP) and advanced practice nursing (APN) roles; however, high variability exists in how NP/APN roles are defined and understood. The aim of this research was to improve our understanding of how the NP/APN is defined globally by: 1) examining role definitions, competencies, and standards of practice for advanced practice nurses internationally; 2) describing from a global perspective the core concepts and common features of NP/APN associated with practice domains; and 3) exploring the utility of text mining and visual analytics in identifying the clustered core concepts common to NP/APN roles organized around the five advanced practice domains of the Strong Advanced Practice Model. This article describes the findings of a secondary analysis of an international NP/APN competency mapping project, using innovative text mining and visual analysis techniques to reexamine and summarize the NP/APN role in 19 countries from Africa, Australia, Asia, Europe, and North America. Although weak aggrupation/associations suggest that further work is needed to define the domains of advanced practice with associated model development, visual analysis points to the identification of common concepts and linkages between concepts for each practice domain of advanced practice outlined in the Strong Model. The secondary text mining and visual analysis presented in this article allows for comparison of core elements between advanced practice role descriptions, standards, and competencies globally to ultimately provide a global perspective on the common features of NP/APN roles and areas where further delineation is required

    PRIVATE SAVINGS IN TRANSITION ECONOMIES: ARE THERE TERMS OF TRADE SHOCKS?

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    The paper examines the impact of terms of trade shocks on private savings in the transition economies after accounting for the effect of other determinants. Economic agents in the transition economies are subject to tight credit constraints which are more pronounced during bad state of nature. Thus, adverse shocks to commodity prices in the world market can force them to reduce savings by a larger amount than they would otherwise have. Empirical analysis using a dynamic panel model and data from twenty one transition economies confirm that most of the determinants of savings identified in the literature also apply to the transition economies. Favorable movements in both the permanent and transitory components of the terms of trade have a significant positive impact on private savings with transitory movements having a larger impact than the permanent component. This reflects the lack of access to foreign borrowing that many of the transition economies have faced during the last decade. Although the impact of terms of trade shocks are found to be asymmetric, the magnitude of the impact appears to be small. The results are robust for alternative estimators, determinants, and country groupings.http://deepblue.lib.umich.edu/bitstream/2027.42/39958/3/wp572.pd

    Development of recommendations for a minimum dataset for Identifying Social factors that Stratify Health Opportunities and Outcomes (ISSHOOs) in pain research

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    There is increasing recognition of the need for researchers to collect and report data that can illuminate health inequities. In pain research, routinely collecting equity-relevant data has the potential to inform about the generalisability of findings; whether the intervention has differential effects across strata of society; or it could be used to guide population targeting for clinical studies. Developing clarity and consensus on what data should be collected and how to collect it is required to prompt researchers to further consider equity issues in the planning, conduct, interpretation, and reporting of research. The overarching aim of the 'Identifying Social Factors that Stratify Health Opportunities and Outcomes' (ISSHOOs) in pain research project is to provide researchers in the pain field with recommendations to guide the routine collection of equity-relevant data. The design of this project is consistent with the methods outlined in the 'Guidance for Developers of Health Research Reporting Guidelines' and involves 4 stages: (i) Scoping review; (ii) Delphi Study; (iii) Consensus Meeting; and (iv) Focus Groups. This stakeholder-engaged project will produce a minimum dataset that has global, expert consensus. Results will be disseminated along with explanation and elaboration as a crucial step towards facilitating future action to address avoidable disparities in pain outcomes. </p

    Development of recommendations for a minimum dataset for Identifying Social factors that Stratify Health Opportunities and Outcomes (ISSHOOs) in pain research

    Get PDF
    There is increasing recognition of the need for researchers to collect and report data that can illuminate health inequities. In pain research, routinely collecting equity-relevant data has the potential to inform about the generalisability of findings; whether the intervention has differential effects across strata of society; or it could be used to guide population targeting for clinical studies. Developing clarity and consensus on what data should be collected and how to collect it is required to prompt researchers to further consider equity issues in the planning, conduct, interpretation, and reporting of research. The overarching aim of the 'Identifying Social Factors that Stratify Health Opportunities and Outcomes' (ISSHOOs) in pain research project is to provide researchers in the pain field with recommendations to guide the routine collection of equity-relevant data. The design of this project is consistent with the methods outlined in the 'Guidance for Developers of Health Research Reporting Guidelines' and involves 4 stages: (i) Scoping review; (ii) Delphi Study; (iii) Consensus Meeting; and (iv) Focus Groups. This stakeholder-engaged project will produce a minimum dataset that has global, expert consensus. Results will be disseminated along with explanation and elaboration as a crucial step towards facilitating future action to address avoidable disparities in pain outcomes. </p

    Development and measurement properties of the AxEL (attitude toward education and advice for low-back-pain) questionnaire

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    Introduction: Clinician time and resources may be underutilised if the treatment they offer does not match patient expectations and attitudes. We developed a questionnaire (AxEL-Q) to guide clinicians toward elements of first-line care that are pertinent to their patients with low back pain. Methods: We used guidance from the COSMIN consortium to develop the questionnaire and evaluated it in a sample of people with low back pain of any duration. Participants were recruited from the community, were over 18 years and fluent in English. Statements that represented first-line care were identified. Semantic scales were used to measure attitude towards these statements. These items were combined to develop the questionnaire draft. Construct validity was evaluated with exploratory factor analysis and hypotheses testing, comparing to the Back Beliefs Questionnaire and modified Pain Self-Efficacy Questionnaire. Reliability was evaluated and floor and ceiling effects calculated. Results: We recruited 345 participants, and had complete data for analysis for 313 participants. The questionnaire draft was reduced to a 3-Factor questionnaire through exploratory factor analysis. Factor 1 comprised 9 items and evaluated Attitude toward staying active, Factor 2 comprised 4 items and evaluated Attitude toward low back pain being rarely caused by a serious health problem, Factor 3 comprised 4 items and evaluated Attitude toward not needing to know the cause of back pain to manage it effectively. There was a strong inverse association between each factor and the Back Beliefs Questionnaire and a moderate positive association with the modified Pain Self-Efficacy Questionnaire. Each independent factor demonstrated acceptable internal consistency; Cronbach α Factor 1 = 0.92, Factor 2 = 0.91, Factor 3 = 0.90 and adequate interclass correlation coefficients; Factor 1 = 0.71, Factor 2 = 0.73, Factor 3 = 0.79. Conclusion: This study demonstrates acceptable construct validity and reliability of the AxEL-Q, providing clinicians with an insight into the likelihood of patients following first-line care at the outset

    Construction and validation of an developmental profile assessment tool for children with autistic spectrum disorder

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    Nos últimos anos a investigação tem dado particular relevância às alterações do Processamento Sensorial nas crianças com perturbações do espectro do autismo (PEA) e a literatura refere que entre 42% a 88% das crianças com PEA apresentam este tipo de disfunção. Nesta linha foi definido um projeto de investigação centrado na construção de uma escala que avalie a tradicional tríade que caracteriza as crianças com PEA (Interação, Comunicação e Comportamento e interesses repetitivos e estereotipados), enriquecida pela inclusão de um novo domínio: o Processamento Sensorial. Com a construção e validação desta escala pretendemos que pais e profissionais utilizem colaborativamente um instrumento de avaliação da intervenção que lhes permita monitorizar o processo de apoio e adequar as suas práticas. Neste artigo descrevemos os procedimentos e os resultados das sucessivas fases de construção do instrumento, desde as análises iniciais mais qualitativas até aos estudos centrados na análise quantitativa dos itens.During the last few years, research has focused on changes in Sensory Processing in children with Autistic Spectrum Disorder (ASD). As a result, literature has shown that between 42% and 88% of children with ASD present this type of disorder. Based on these findings, a research project was designed centring on the construction of a tool to assess the traditional triad that characterizes children with ASD (Interaction, Communication and Behaviour and Repetitive and Stereotyped Interests), to which was added a new domain: Sensory Processing. By constructing and validating this assessment tool, the intention is for parents and professionals to collaboratively apply this intervention assessment instrument in order to monitor the support process and adapt their practices. In this paper, we describe procedures and results of the successive stages entailed in constructing this instrument, from the first primarily qualitative analyses up to the studies centred on the quantitative item analysis.Fundação para a Ciência e Tecnologia (FCT)ABPEE - Associação Brasileira de Pesquisadores em Educação EspecialConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CAPESMinistério da Educação - BrasilMinistério da Ciência e da Tecnologia - BrasilGoverno Federal - Brasi

    The translation, validity and reliability of the German version of the Fremantle Back Awareness Questionnaire

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    Background: The Fremantle Back Awareness Questionnaire (FreBAQ) claims to assess disrupted self-perception of the back. The aim of this study was to develop a German version of the Fre-BAQ (FreBAQ-G) and assess its test-retest reliability, its known-groups validity and its convergent validity with another purported measure of back perception. Methods: The FreBaQ-G was translated following international guidelines for the transcultural adaptation of questionnaires. Thirty-five patients with non-specific CLBP and 48 healthy participants were recruited. Assessor one administered the FreBAQ-G to each patient with CLBP on two separate days to quantify intra-observer reliability. Assessor two administered the FreBaQ-G to each patient on day 1. The scores were compared to those obtained by assessor one on day 1 to assess inter-observer reliability. Known-groups validity was quantified by comparing the FreBAQ-G score between patients and healthy controls. To assess convergent validity, patient\u27s FreBAQ-G scores were correlated to their two-point discrimination (TPD) scores. Results: Intra- and Inter-observer reliability were both moderate with ICC3.1 = 0.88 (95%CI: 0.77 to 0.94) and 0.89 (95%CI: 0.79 to 0.94), respectively. Intra- and inter-observer limits of agreement (LoA) were 6.2 (95%CI: 5.0±8.1) and 6.0 (4.8±7.8), respectively. The adjusted mean difference between patients and controls was 5.4 (95%CI: 3.0 to 7.8, p\u3c0.01). Patient\u27s FreBAQ-G scores were not associated with TPD thresholds (Pearson\u27s r = -0.05, p = 0.79). Conclusions: The FreBAQ-G demonstrated a degree of reliability and known-groups validity. Interpretation of patient level data should be performed with caution because the LoA were substantial. It did not demonstrate convergent validity against TPD. Floor effects of some items of the FreBAQ-G may have influenced the validity and reliability results. The clinimetric properties of the FreBAQ-G require further investigation as a simple measure of disrupted self-perception of the back before firm recommendations on its use can be made
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