2,143 research outputs found
Recreation of the terminal events in physiological integrin activation.
Increased affinity of integrins for the extracellular matrix (activation) regulates cell adhesion and migration, extracellular matrix assembly, and mechanotransduction. Major uncertainties concern the sufficiency of talin for activation, whether conformational change without clustering leads to activation, and whether mechanical force is required for molecular extension. Here, we reconstructed physiological integrin activation in vitro and used cellular, biochemical, biophysical, and ultrastructural analyses to show that talin binding is sufficient to activate integrin alphaIIbbeta3. Furthermore, we synthesized nanodiscs, each bearing a single lipid-embedded integrin, and used them to show that talin activates unclustered integrins leading to molecular extension in the absence of force or other membrane proteins. Thus, we provide the first proof that talin binding is sufficient to activate and extend membrane-embedded integrin alphaIIbbeta3, thereby resolving numerous controversies and enabling molecular analysis of reconstructed integrin signaling
A Study of the Diverse T Dwarf Population Revealed by WISE
We report the discovery of 87 new T dwarfs uncovered with the Wide-field
Infrared Survey Explorer (WISE) and three brown dwarfs with extremely red
near-infrared colors that exhibit characteristics of both L and T dwarfs. Two
of the new T dwarfs are likely binaries with L7+/-1 primaries and mid-type T
secondaries. In addition, our follow-up program has confirmed 10 previously
identified T dwarfs and four photometrically-selected L and T dwarf candidates
in the literature. This sample, along with the previous WISE discoveries,
triples the number of known brown dwarfs with spectral types later than T5.
Using the WISE All-Sky Source Catalog we present updated color-color and
color-type diagrams for all the WISE-discovered T and Y dwarfs. Near-infrared
spectra of the new discoveries are presented, along with spectral
classifications. To accommodate later T dwarfs we have modified the integrated
flux method of determining spectral indices to instead use the median flux.
Furthermore, a newly defined J-narrow index differentiates the early-type Y
dwarfs from late-type T dwarfs based on the J-band continuum slope. The K/J
indices for this expanded sample show that 32% of late-type T dwarfs have
suppressed K-band flux and are blue relative to the spectral standards, while
only 11% are redder than the standards. Comparison of the Y/J and K/J index to
models suggests diverse atmospheric conditions and supports the possible
re-emergence of clouds after the L/T transition. We also discuss peculiar brown
dwarfs and candidates that were found not to be substellar, including two Young
Stellar Objects and two Active Galactic Nuclei. The coolest WISE-discovered
brown dwarfs are the closest of their type and will remain the only sample of
their kind for many years to come.Comment: Accepted to ApJS on 15 January 2013; 99 pages in preprint format, 30
figures, 12 table
A T8.5 Brown Dwarf Member of the Xi Ursae Majoris System
The Wide-field Infrared Survey Explorer has revealed a T8.5 brown dwarf (WISE
J111838.70+312537.9) that exhibits common proper motion with a
solar-neighborhood (8 pc) quadruple star system - Xi Ursae Majoris. The angular
separation is 8.5 arc-min, and the projected physical separation is about 4000
AU. The sub-solar metallicity and low chromospheric activity of Xi UMa A argue
that the system has an age of at least 2 Gyr. The infrared luminosity and color
of the brown dwarf suggests the mass of this companion ranges between 14 and 38
Jupiter masses for system ages of 2 and 8 Gyr respectively.Comment: AJ in press, 12 pages LaTeX with 6 figures. More astrometric data and
a laser guide star adaptive optics image adde
Symptoms and quality of life in patients with suspected angina undergoing CT coronary angiography: a randomised controlled trial.
BACKGROUND: In patients with suspected angina pectoris, CT coronary angiography (CTCA) clarifies the diagnosis, directs appropriate investigations and therapies, and reduces clinical events. The effect on patient symptoms is currently unknown. METHODS: In a prospective open-label parallel group multicentre randomised controlled trial, 4146 patients with suspected angina due to coronary heart disease were randomised 1:1 to receive standard care or standard care plus CTCA. Symptoms and quality of life were assessed over 6 months using the Seattle Angina Questionnaire and Short Form 12. RESULTS: Baseline scores indicated mild physical limitation (74±0.4), moderate angina stability (44±0.4), modest angina frequency (68±0.4), excellent treatment satisfaction (92±0.2) and moderate impairment of quality of life (55±0.3). Compared with standard care alone, CTCA was associated with less marked improvements in physical limitation (difference -1.74 (95% CIs, -3.34 to -0.14), p=0.0329), angina frequency (difference -1.55 (-2.85 to -0.25), p=0.0198) and quality of life (difference -3.48 (-4.95 to -2.01), p<0.0001) at 6 months. For patients undergoing CTCA, improvements in symptoms were greatest in those diagnosed with normal coronary arteries or who had their preventative therapy discontinued, and least in those with moderate non-obstructive disease or had a new prescription of preventative therapy (p<0.001 for all). CONCLUSIONS: While improving diagnosis, treatment and outcome, CTCA is associated with a small attenuation of the improvements in symptoms and quality of life due to the detection of moderate non-obstructive coronary artery disease. TRIAL REGISTRATION NUMBER: NCT01149590
Discordant American College of Physicians and international rheumatology guidelines for gout management: consensus statement of the Gout, Hyperuricemia and Crystal-Associated Disease Network (G-CAN).
In November 2016, the American College of Physicians (ACP) published a clinical practice guideline on the management of acute and recurrent gout. This guideline differs substantially from the latest guidelines generated by the American College of Rheumatology (ACR), European League Against Rheumatism (EULAR) and 3e (Evidence, Expertise, Exchange) Initiative, despite reviewing largely the same body of evidence. The Gout, Hyperuricemia and Crystal-Associated Disease Network (G-CAN) convened an expert panel to review the methodology and conclusions of these four sets of guidelines and examine possible reasons for discordance between them. The G-CAN position, presented here, is that the fundamental pathophysiological knowledge underlying gout care, and evidence from clinical experience and clinical trials, supports a treat-to-target approach for gout aimed at lowering serum urate levels to below the saturation threshold at which monosodium urate crystals form. This practice, which is truly evidence-based and promotes the steady reduction in tissue urate crystal deposits, is promoted by the ACR, EULAR and 3e Initiative recommendations. By contrast, the ACP does not provide a clear recommendation for urate-lowering therapy (ULT) for patients with frequent, recurrent flares or those with tophi, nor does it recommend monitoring serum urate levels of patients prescribed ULT. Results from emerging clinical trials that have gout symptoms as the primary end point are expected to resolve this debate for all clinicians in the near term future
Decision modelling in donation after circulatory death (DCD) liver transplantation.
Introduction: Donation after circulatory death (DCD) liver allografts are increasingly used for transplantation. However, the post-transplantation clinical and quality of life outcomes of DCD recipients are traditionally considered to be inferior compared with donation after brain death (DBD) allograft recipients. Decision making for such marginal organs can be difficult. This study investigated the optimal decision to accept or decline a DCD liver allograft for a patient based on their current health. Methods: A Markov decision process model was constructed to predict the 5 year clinical course of patients on the liver transplant waiting list. Clinical outcomes were determined from the UK Transplant registry or appropriate literature. Quality-adjusted life years (QALYs) were determined using the condition-specific “Short form of liver disease quality of life” (SF-LDQOL) questionnaire. Results: There were 293 / 374 (78.3%) eligible patients who completed the SF-LDQOL questionnaire. Seventy-three respondents (24.9%) were pre-transplant and 220 were post-transplant (DBD-recipient, 57.0%; DCD-recipient, 10.2%; re-transplant recipient, 7.9%). Predictive modelling indicated that quality-adjusted life years (QALYs) gained at 5 years were significantly higher in DCD-recipients (3.77, 95% CI=3.44–4.10) compared to those who remained on the waiting list for a DBD transplant with model of end-stage liver disease (MELD) scores of 15-20 (3.36, 95% CI=3.28–3.43), or >20 (3.07, 95% CI=3.00–3.14). There was no significant advantage for individuals with MELD scores <15 (3.55, 95% CI=3.47–3.63). Conclusion: This model predicts that patients on the UK liver transplant waiting list with MELD scores >15 should receive an offered DCD allograft based on the QALYs gained at 5 years. This analysis only accounts for donor-recipient risk pairings seen in current practice. The optimal decision for patients with MELD scores <15 remains unclear, however a survival benefit was observed when a DCD organ was accepted
Fine-Scale Mapping of the 4q24 Locus Identifies Two Independent Loci Associated with Breast Cancer Risk
Background: A recent association study identified a common variant (rs9790517) at 4q24 to be associated with breast cancer risk. Independent association signals and potential functional variants in this locus have not been explored.
Methods: We conducted a fine-mapping analysis in 55,540 breast cancer cases and 51,168 controls from the Breast Cancer Association Consortium.
Results: Conditional analyses identified two independent association signals among women of European ancestry, represented by rs9790517 [conditional P = 2.51 × 10−4; OR, 1.04; 95% confidence interval (CI), 1.02–1.07] and rs77928427 (P = 1.86 × 10−4; OR, 1.04; 95% CI, 1.02–1.07). Functional annotation using data from the Encyclopedia of DNA Elements (ENCODE) project revealed two putative functional variants, rs62331150 and rs73838678 in linkage disequilibrium (LD) with rs9790517 (r2 ≥ 0.90) residing in the active promoter or enhancer, respectively, of the nearest gene, TET2. Both variants are located in DNase I hypersensitivity and transcription factor–binding sites. Using data from both The Cancer Genome Atlas (TCGA) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), we showed that rs62331150 was associated with level of expression of TET2 in breast normal and tumor tissue.
Conclusion: Our study identified two independent association signals at 4q24 in relation to breast cancer risk and suggested that observed association in this locus may be mediated through the regulation of TET2.
Impact: Fine-mapping study with large sample size warranted for identification of independent loci for breast cancer risk
Readiness for implementation of novel digital health interventions for postoperative monitoring:a systematic review and clinical innovation network analysis
An increasing number of digital health interventions (DHIs) for remote postoperative monitoring have been developed and evaluated. This systematic review identifies DHIs for postoperative monitoring and evaluates their readiness for implementation into routine health care. Studies were defined according to idea, development, exploration, assessment, and long-term follow-up (IDEAL) stages of innovation. A novel clinical innovation network analysis used coauthorship and citations to examine collaboration and progression within the field. 126 DHIs were identified, with 101 (80%) being early stage innovations (IDEAL stage 1 and 2a). None of the DHIs identified had large-scale routine implementation. There is little evidence of collaboration, and there are clear omissions in the evaluation of feasibility, accessibility, and the health-care impact. Use of DHIs for postoperative monitoring remains at an early stage of innovation, with promising but generally low-quality supporting evidence. Comprehensive evaluation within high-quality, large-scale trials and real-world data are required to definitively establish readiness for routine implementation
Validation of the OAKS prognostic model for acute kidney injury after gastrointestinal surgery
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