707 research outputs found

    A re-examination of the BEST Trial using composite outcomes, including emergency department visits

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    Objectives: The influence of choice of endpoint on trial size, duration, and interpretation of results was examined in patients with heart failure who were enrolled in BEST (Beta-blocker Evaluation of Survival Trial). Background: The choice of endpoints in heart failure trials has evolved over the past 3 decades. Methods: In the BEST trial, we used Cox regression analysis to examine the effect of bucindolol on the current standard composite of cardiovascular death or heart failure hospitalization (CVD/HFH) compared with the original primary mortality endpoint and the expanded composite that included emergency department (ED) visits. We also undertook an analysis of recurrent events primarily using the Lin, Wei, Ying, and Yang model. Results: Overall, 448 (33%) patients on placebo and 411 (30%) patients on bucindolol died (hazard ratio [HR]: 0.90; 95% confidence interval [CI]: 0.78 to 1.02; p = 0.11). A total of 730 (54%) patients experienced CVD/HFH on placebo and 624 (46%) on bucindolol (HR: 0.80; 95% CI: 0.72 to 0.89; p < 0.001). Adding ED visits increased these numbers to 768 (57%) and 668 (49%), respectively (HR: 0.81; 95% CI: 0.73 to 0.90; p < 0.001). A total of 568 (42%) patients on placebo experienced HFH compared with 476 (35%) patients on bucindolol (HR: 0.78; 95% CI: 0.69 to 0.89; p < 0.001), with a total of 1,333 and 1,124 admissions, respectively. With the same statistical assumptions, using the composite endpoint instead of all-cause mortality would have reduced the trial size by 40% and follow-up duration by 69%. The rate ratio for recurrent events (CVD/HFH) was 0.83 (95% CI: 0.73 to 0.94; p = 0.003). Conclusions: Choice of endpoint has major implications for trial size and duration, as well as interpretation of results. The value of broader composite endpoints and inclusion of recurrent events needs further investigation. (Beta Blocker Evaluation in Survival Trial [BEST]; NCT00000560

    Analysis of recurrent events with an associated informative dropout time: Application of the joint frailty model.

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    This paper considers the analysis of a repeat event outcome in clinical trials of chronic diseases in the context of dependent censoring (e.g. mortality). It has particular application in the context of recurrent heart failure hospitalisations in trials of heart failure. Semi-parametric joint frailty models (JFMs) simultaneously analyse recurrent heart failure hospitalisations and time to cardiovascular death, estimating distinct hazard ratios whilst individual-specific latent variables induce associations between the two processes. A simulation study was carried out to assess the suitability of the JFM versus marginal analyses of recurrent events and cardiovascular death using standard methods. Hazard ratios were consistently overestimated when marginal models were used, whilst the JFM produced good, well-estimated results. An application to the Candesartan in Heart failure: Assessment of Reduction in Mortality and morbidity programme was considered. The JFM gave unbiased estimates of treatment effects in the presence of dependent censoring. We advocate the use of the JFM for future trials that consider recurrent events as the primary outcome. © 2016 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd

    Focus on changing fire regimes: interactions with climate, ecosystems, and society

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    Fire is a complex Earth system phenomenon that fundamentally affects vegetation distributions, biogeochemical cycling, climate, and human society across most of Earth’s land surface. Fire regimes are currently changing due to multiple interacting global change drivers, most notably climate change, land use, and direct human influences via ignition and suppression. It is therefore critical to better understand the drivers, patterns, and impacts of these changing fire regimes now and continuing into the future. Our review contributes to this focus issue by synthesizing results from 27 studies covering a broad range of topics. Studies are categorized into (i) Understanding contemporary fire patterns, drivers, and effects; (ii) Human influences on fire regimes; (iii) Changes in historical fire regimes; (iv) Future projections; (v) Novel techniques; and (vi) Reviews. We conclude with a discussion on progress made, major remaining research challenges, and recommended directions

    Rethinking the Core List of Journals for Libraries that Serve Schools and Colleges of Pharmacy.

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    The Core List of Journals for Libraries that Serve Schools and Colleges of Pharmacy is a guide for developing and maintaining pharmacy-affiliated library collections. A work group was created to update the list and design a process for updating that will streamline future revisions. Work group members searched the National Library of Medicine catalog for an initial list of journals and then applied inclusion criteria to narrow the list. The work group finalized the fifth edition of the list with 225 diverse publications and produced a sustainable set of criteria for journal inclusion, providing a structured, objective process for future updates

    Plasmodium falciparum ligand binding to erythrocytes induce alterations in deformability essential for invasion

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    The most lethal form of malaria in humans is caused by Plasmodium falciparum. These parasites invade erythrocytes, a complex process involving multiple ligand-receptor interactions. The parasite makes initial contact with the erythrocyte followed by dramatic deformations linked to the function of the Erythrocyte binding antigen family and P. falciparum reticulocyte binding-like families. We show EBA-175 mediates substantial changes in the deformability of erythrocytes by binding to glycophorin A and activating a phosphorylation cascade that includes erythrocyte cytoskeletal proteins resulting in changes in the viscoelastic properties of the host cell. TRPM7 kinase inhibitors FTY720 and waixenicin A block the changes in the deformability of erythrocytes and inhibit merozoite invasion by directly inhibiting the phosphorylation cascade. Therefore, binding of P. falciparum parasites to the erythrocyte directly activate a signaling pathway through a phosphorylation cascade and this alters the viscoelastic properties of the host membrane conditioning it for successful invasion

    Q methodology and a Delphi poll: a useful approach to researching a narrative approach to therapy

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    Q methodology and a Delphi poll combined qualitative and quantitative methods to explore definitions of White and Epston's (1990) narrative approach to therapy among a group of UK practitioners. A Delphi poll was used to generate statements about narrative therapy. The piloting of statements by the Delphi panel identified agreement about theoretical ideas underpinning narrative therapy and certain key practices. A wider group of practitioners ranked the statements in a Q sort and made qualitative comments about their sorting. Quantitative methods (principal components analysis) were used to extract eight accounts of narrative therapy, five of which are qualitatively analysed in this paper. Agreement and differences were identified across a range of issues, including the social construction of narratives, privileging a political stance or narrative techniques and the relationship with other therapies, specifically systemic psychotherapy. Q methodology, combined with the Delphi poll, was a unique and innovative feature of this study

    Calcifying algae maintain settlement cues to larval abalone following algal exposure to extreme ocean acidification

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    Ocean acidification (OA) increasingly threatens marine systems, and is especially harmful to calcifying organisms. One important question is whether OA will alter species interactions. Crustose coralline algae (CCA) provide space and chemical cues for larval settlement. CCA have shown strongly negative responses to OA in previous studies, including disruption of settlement cues to corals. In California, CCA provide cues for seven species of harvested, threatened, and endangered abalone. We exposed four common CCA genera and a crustose calcifying red algae, Peyssonnelia (collectively CCRA) from California to three pCO levels ranging from 419-2,013 µatm for four months. We then evaluated abalone (Haliotis rufescens) settlement under ambient conditions among the CCRA and non-algal controls that had been previously exposed to the pCO treatments. Abalone settlement and metamorphosis increased from 11% in the absence of CCRA to 45-69% when CCRA were present, with minor variation among CCRA genera. Though all CCRA genera reduced growth during exposure to increased pCO , abalone settlement was unaffected by prior CCRA exposure to increased pCO . Thus, we find no impacts of OA exposure history on CCRA provision of settlement cues. Additionally, there appears to be functional redundancy in genera of CCRA providing cues to abalone, which may further buffer OA effects

    Depalmitoylated Ras traffics to and from the Golgi complex via a nonvesicular pathway

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    Palmitoylation is postulated to regulate Ras signaling by modulating its intracellular trafficking and membrane microenvironment. The mechanisms by which palmitoylation contributes to these events are poorly understood. Here, we show that dynamic turnover of palmitate regulates the intracellular trafficking of HRas and NRas to and from the Golgi complex by shifting the protein between vesicular and nonvesicular modes of transport. A combination of time-lapse microscopy and photobleaching techniques reveal that in the absence of palmitoylation, GFP-tagged HRas and NRas undergo rapid exchange between the cytosol and ER/Golgi membranes, and that wild-type GFP-HRas and GFP-NRas are recycled to the Golgi complex by a nonvesicular mechanism. Our findings support a model where palmitoylation kinetically traps Ras on membranes, enabling the protein to undergo vesicular transport. We propose that a cycle of depalmitoylation and repalmitoylation regulates the time course and sites of Ras signaling by allowing the protein to be released from the cell surface and rapidly redistributed to intracellular membranes

    Cellular Targeting in Autoimmunity

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    Many biologic agents that were first approved for the treatment of malignancies are now being actively investigated and used in a variety of autoimmune diseases such as rheumatoid arthritis (RA), antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, systemic lupus erythematosus (SLE), and Sjogren’s syndrome. The relatively recent advance of selective immune targeting has significantly changed the management of autoimmune disorders, and in part, can be attributed to the progress made in understanding effector cell function and their signaling pathways. In this review, we will discuss the recent FDA approved biologic therapies that directly target immune cells as well as the most promising investigational drugs affecting immune cell function and signaling for the treatment of autoimmune disease

    Dendritic cell based PSMA immunotherapy for prostate cancer using a CD40-targeted adenovirus vector

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    Human prostate tumor vaccine and gene therapy trials using ex vivo methods to prime dendritic cells (DCs) with prostate specific membrane antigen (PSMA) have been somewhat successful, but to date the lengthy ex vivo manipulation of DCs has limited the widespread clinical utility of this approach. Our goal was to improve upon cancer vaccination with tumor antigens by delivering PSMA via a CD40-targeted adenovirus vector directly to DCs as an efficient means for activation and antigen presentation to T-cells. To test this approach, we developed a mouse model of prostate cancer by generating clonal derivatives of the mouse RM-1 prostate cancer cell line expressing human PSMA (RM-1-PSMA cells). To maximize antigen presentation in target cells, both MHC class I and TAP protein expression was induced in RM-1 cells by transduction with an Ad vector expressing interferon-gamma (Ad5-IFNγ). Administering DCs infected ex vivo with CD40-targeted Ad5-huPSMA, as well as direct intraperitoneal injection of the vector, resulted in high levels of tumor-specific CTL responses against RM-1-PSMA cells pretreated with Ad5-IFNγ as target cells. CD40 targeting significantly improved the therapeutic antitumor efficacy of Ad5-huPSMA encoding PSMA when combined with Ad5-IFNγ in the RM-1-PSMA model. These results suggest that a CD-targeted adenovirus delivering PSMA may be effective clinically for prostate cancer immunotherapy
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