3,164 research outputs found

    The Great Eruption of Eta Carinae

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    During the years 1838-1858, the very massive star {\eta} Carinae became the prototype supernova impostor: it released nearly as much light as a supernova explosion and shed an impressive amount of mass, but survived as a star.1 Based on a light-echo spectrum of that event, Rest et al.2 conclude that "a new physical mechanism" is required to explain it, because the gas outflow appears cooler than theoretical expectations. Here we note that (1) theory predicted a substantially lower temperature than they quoted, and (2) their inferred observational value is quite uncertain. Therefore, analyses so far do not reveal any significant contradiction between the observed spectrum and most previous discussions of the Great Eruption and its physics.Comment: To appear in Nature, a brief communication arising in response to Rest et al. 2012. Submitted to Nature February 17, 201

    An online survey of Australian physicians reported practice with the off-label use of nebulised frusemide

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    Background: Off-label prescribing is common in palliative care. Despite inconsistent reports of the benefit of nebulised frusemide for breathlessness, its use continues to be reported. Methods. An online survey was emailed to 249 members of the Australian and New Zealand Society of Palliative Medicine to estimate the use of nebulised frusemide for breathlessness by Australian physicians involved in palliative care in the previous 12 months. Results: There were 52/249 (21%) respondents to the survey. The majority (44/52; 85%) had not prescribed nebulised frusemide in the previous 12 months. The most common (18/44; 43%) reason for not prescribing nebulised frusemide was a belief that there was not enough evidence to support its use. Whilst only a few respondents (8/52; 15%) reported having used nebulised frusemide, all that had used it thought there was at least some benefit in relieving breathlessness. Conclusion: This report adds to the series of case studies reporting some benefit from nebulised frusemide in relieving breathlessnes. © 2012 Newton et al.; licensee BioMed Central Ltd

    Investing in Skilled Specialists to Grow Hospital Infrastructure for Quality Improvement.

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    OBJECTIVES: Hospitals can reduce labor costs by hiring lowest skill possible for the job, stretching clinical hours, and reducing staff not at bedside. However, these labor constraints designed to reduce costs may paradoxically increase costs. Specialty staff, such as board-certified clinicians, can redesign health systems to evaluate the needs of complex patients and prevent complications. The aim of the study was to evaluate whether investing in skilled specialists for supporting hospital quality infrastructure improves value and performance. METHODS: We evaluated pressure injury rates as an indicator of performance in a retrospective observational cohort of 55 U.S. academic hospitals from the Vizient clinical database between 2007 and 2012. Pressure injuries were defined by U.S. Agency for Healthcare Research and Quality (AHRQ) Patient Safety Indicator 3 (PSI-03) for stage 3, 4, and unstageable pressure injuries not present on admission in hospitalized adults. We compared ratios of board-certified wound care nurses per 1000 hospital beds to hospital-acquired pressure injury rates in these hospitals using mixed-effects regression of hospital quarters. RESULTS: High-performing hospitals invested in prevention infrastructure with skilled specialists and observed performance improvements. Regression indicated that by adding one board-certified wound care nurse per 1000 hospital beds, hospitals had associated decreases in pressure injury rates by -17.7% relative to previous quarters, controlling for other interruptions. Highest performers supplied fewer skilled specialists and achieve improved outcomes. CONCLUSIONS: Skilled specialists bring important value to health systems as a representation of investment in infrastructure, and the proportion of these specialists could be scaled relative to the hospital's patient capacity. Policy should support hospitals to make investments in infrastructure to drive down patient costs and improve quality

    In pursuit of certainty: Can the systematic review process deliver?

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    Background: There has been increasing emphasis on evidence-based approaches to improve patient outcomes through rigorous, standardised and well-validated approaches. Clinical guidelines drive this process and are largely developed based on the findings of systematic reviews (SRs). This paper presents a discussion of the SR process in providing decisive information to shape and guide clinical practice, using a purpose-built review database: the Cochrane reviews; and focussing on a highly prevalent medical condition: hypertension. Methods. We searched the Cochrane database and identified 25 relevant SRs incorporating 443 clinical trials. Reviews with the terms 'blood pressure' or 'hypertension' in the title were included. Once selected for inclusion, the abstracts were assessed independently by two authors for their capacity to inform and influence clinical decision-making. The inclusions were independently audited by a third author. Results: Of the 25 SRs that formed the sample, 12 provided conclusive findings to inform a particular treatment pathway. The evidence-based approaches offer the promise of assisting clinical decision-making through clarity, but in the case of management of blood pressure, half of the SRs in our sample highlight gaps in evidence and methodological limitations. Thirteen reviews were inconclusive, and eight, including four of the 12 conclusive SRs, noted the lack of adequate reporting of potential adverse effects or incidence of harm. Conclusions: These findings emphasise the importance of distillation, interpretation and synthesis of information to assist clinicians. This study questions the utility of evidence-based approaches as a uni-dimensional approach to improving clinical care and underscores the importance of standardised approaches to include adverse events, incidence of harm, patient's needs and preferences and clinician's expertise and discretion. © 2013 Saltman et al; licensee BioMed Central Ltd

    Arf GTPase interplay with Rho GTPases in regulation of the actin cytoskeleton

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    The Arf and Rho subfamilies of small GTPases are nucleotide-dependent molecular switches that act as master regulators of vesicular trafficking and the actin cytoskeleton organization. Small GTPases control cell processes with high fidelity by acting through distinct repertoires of binding partners called effectors. While we understand a great deal about how these GTPases act individually, relatively little is known about how they cooperate, especially in the control of effectors. This review highlights how Arf GTPases collaborate with Rac1 to regulate actin cytoskeleton dynamics at the membrane via recruiting and activating the Wave Regulatory Complex (WRC), a Rho effector that underpins lamellipodia formation and macropinocytosis. This provides insight into Arf regulation of the actin cytoskeleton, whilst putting the spotlight on small GTPase cooperation with emerging evidence of its importance in fundamental cell biology and interactions with pathogenic bacteria

    Barriers and enablers to adherence to anticoagulation in heart failure with atrial fibrillation: patient and provider perspectives

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    © 2017 John Wiley & Sons Ltd Aims & Objectives: The purpose of this study was to elucidate the barriers and enablers to adherence to anticoagulation in individuals with chronic heart failure (CHF) with concomitant atrial fibrillation (AF) from the perspective of patients and providers. Background: CHF and AF commonly coexist and are associated with increased stroke risk and mortality. Oral anticoagulation significantly reduces stroke risk and improves outcomes. Yet, in approximately 30% of cases, anticoagulation is not commenced for a variety of reasons. Design: Qualitative study using narrative inquiry. Methods: Data from face-to-face individual interviews with patients and information retrieved from healthcare file note review documented the clinician perspective. This study is a synthesis of the two data sources, obtained during patient clinical assessments as part of the Atrial Fibrillation And Stroke Thromboprophylaxis in hEart failuRe (AFASTER) Study. Results: Patient choice and preference were important factors in anticoagulation decisions, including treatment burden, unfavourable or intolerable side effects and patient refusal. Financial barriers included cost of travel, medication cost and reimbursement. Psychological factors included psychiatric illness, cognitive impairment and depression. Social barriers included homelessness and the absence of a caregiver or lack of caregiver assistance. Clinician reticence included fear of falls, frailty, age, fear of bleeding and the challenges of multimorbidity. Facilitators to successful prescription and adherence were caregiver support, reminders and routine, self-testing and the use of technology. Conclusions: Many barriers remain to high-risk individuals being prescribed anticoagulation for stroke prevention. There are a number of enabling factors that facilitate prescription and optimise treatment adherence. Nurses should challenge these treatment barriers and seek enabling factors to optimise therapy. Relevance to clinical practice: Nurses can help patients and caregivers to understand complex anticoagulant risk-benefit information, and act as a patient advocate when making complex stroke prevention decisions

    Atrial fibrillation and thromboprophylaxis in heart failure: The need for patient-centered approaches to address adherence

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    Atrial fibrillation is a common arrhythmia in heart failure and a risk factor for stroke. Risk assessment tools can assist clinicians with decision making in the allocation of thromboprophylaxis. This review provides an overview of current validated risk assessment tools for atrial fibrillation and emphasizes the importance of tailoring individual risk and the importance of weighing the benefits of treatment. Further, this review provides details of innovative and patient-centered methods for ensuring optimal adherence to prescribed therapy. Prior to initiating oral anticoagulant therapy, a comprehensive risk assessment should include evaluation of associated cardiogeriatric conditions, potential for adherence to prescribed therapy, frailty, and functional and cognitive ability. © 2013 Ferguson et al, publisher and licensee Dove Medical Press Ltd

    Cardiovascular disease in women: Implications for improving health outcomes

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    Objective: To collate data on women and cardiovascular disease in Australia and globally to inform public health campaigns and health care interventions. Design: Literature review. Results: •Women with acute coronary syndromes show consistently poorer outcomes than men, independent of comorbidity and management, despite less anatomical obstruction of coronary arteries and relatively preserved left ventricular function. Higher mortality and complication rates are best documented amongst younger women and those with ST-segment-elevation myocardial infarction.•Sex differences in atherogenesis and cardiovascular adaptation have been hypothesised, but not proven.•Atrial fibrillation carries a relatively greater risk of stroke in women than in men, and anticoagulation therapy is associated with higher risk of bleeding complications.•The degree of risk conferred by single cardiovascular risk factors and combinations of risk factors may differ between the sexes, and marked postmenopausal changes are seen in some risk factors.•Sociocultural factors, delays in seeking care and differences in self-management behaviours may contribute to poorer outcomes in women.•Differences in clinical management for women, including higher rates of misdiagnosis and less aggressive treatment, have been reported, but there is a lack of evidence to determine their effects on outcomes, especially in angina.•Although enrolment of women in randomised clinical trials has increased since the 1970s, women remain underrepresented in cardiovascular clinical trials. Conclusions: Improvement in the prevention and management of CVD in women will require a deeper understanding of women's needs by the community, health care professionals, researchers and government. © 2011 Royal College of Nursing, Australia

    A critical role for the chromatin remodeller CHD7 in anterior mesoderm during cardiovascular development

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    CHARGE syndrome is caused by spontaneous loss-of-function mutations to the ATP-dependant chromatin remodeller chromodomain-helicase-DNA-binding protein 7 (CHD7). It is characterised by a distinct pattern of congenital anomalies, including cardiovascular malformations. Disruption to the neural crest lineage has previously been emphasised in the aetiology of this developmental disorder. We present evidence for an additional requirement for CHD7 activity in the Mesp1-expressing anterior mesoderm during heart development. Conditional ablation of Chd7 in this lineage results in major structural cardiovascular defects akin to those seen in CHARGE patients, as well as a striking loss of cardiac innervation and embryonic lethality. Genome-wide transcriptional analysis identified aberrant expression of key components of the Class 3 Semaphorin and Slit-Robo signalling pathways in Chd7(fl/fl);Mesp1-Cre mutant hearts. CHD7 localises at the Sema3c promoter in vivo, with alteration of the local chromatin structure seen following Chd7 ablation, suggestive of direct transcriptional regulation. Furthermore, we uncover a novel role for CHD7 activity upstream of critical calcium handling genes, and demonstrate an associated functional defect in the ability of cardiomyocytes to undergo excitation-contraction coupling. This work therefore reveals the importance of CHD7 in the cardiogenic mesoderm for multiple processes during cardiovascular development
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