4,453 research outputs found

    The big question remains unanswered

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    Surgical management of aortic root disease in Marfan syndrome and other congenital disorders associated with aortic root aneurysms

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    Elective root replacement in Marfan syndrome has improved life expectancy in affected patients. Three forms of surgery are now available: total root replacement (TRR) with a valved conduit, valve sparing root replacement (VSRR) and personalised external aortic root support (PEARS) with a macroporous mesh sleeve. TRR can be performed irrespective of aortic dimensions and a mechanical replacement valve is a secure and near certain means of correcting aortic valve regurgitation but has thromboembolic and bleeding risks. VSRR offers freedom from anticoagulation and attendant risks of bleeding but reoperation for aortic regurgitation runs at 1.3% per annum. A prospective multi-institutional study has found this to be an underestimate of the true rate of valve-related adverse events. PEARS conserves the aortic root anatomy and optimises the chance of maintaining valve function but average follow-up is under 5 years and so the long-term results are yet to be determined. Patients are on average in their 30s and so the cumulative lifetime need for reoperation, and of any valve-related complications, are consequently substantial. With lowering surgical risk of prophylactic root replacement, the threshold for intervention has reduced progressively over 30 years to 4.5 cm and so an increasing number of patients who are not destined to have a dissection are now having root replacement. In evaluation of these three forms of surgery, the number needed to treat to prevent dissection and the balance of net benefit and harm in future patients must be considered

    A new device for acquiring ground truth on the absorption of light by turbid waters

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    The author has identified the following significant results. A new device, called a Spectral Attenuation Board, has been designed and tested, which enables ERTS-1 sea truth collection teams to monitor the attenuation depths of three colors continuously, as the board is being towed behind a boat. The device consists of a 1.2 x 1.2 meter flat board held below the surface of the water at a fixed angle to the surface of the water. A camera mounted above the water takes photographs of the board. The resulting film image is analyzed by a micro-densitometer trace along the descending portion of the board. This yields information on the rate of attenuation of light penetrating the water column and the Secchi depth. Red and green stripes were painted on the white board to approximate band 4 and band 5 of the ERTS MSS so that information on the rate of light absorption by the water column of light in these regions of the visible spectrum could be concurrently measured. It was found that information from a red, green, and white stripe may serve to fingerprint the composition of the water mass. A number of these devices, when automated, could also be distributed over a large region to provide a cheap method of obtaining valuable satellite ground truth data at present time intervals

    Should doctors leave the history of medicine to historians?

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    A 'compare and contrast' exercise: wrapping versus personalised external aortic root support (PEARS)

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    Wrapping of the aorta and personalised external aortic root support (PEARS) both have the purpose of preventing further expansion of the ascending aorta in order to reduce the risk of aortic dissection and to spare the patient the disastrous consequences of aortic rupture. For the first time, Plonek and colleagues have reported systematically the CT appearances of a series of cases of wrapping. They illustrate the important finding that there are residual spaces between the aorta and the wrap. PEARS by contrast is intimately in contact with the aorta due to its personalised design and is fully incorporated due it construction from a porous mesh. A limitation of PEARS is that it is, of its nature, a planned and elective operation while wrapping can be undertaken during an emergency operation and can be used without prior planning as an intraoperative decision

    Predicting Students’ Physical Activity and Health-Related Well-Being: A Prospective Cross-Domain Investigation of Motivation Across School Physical Education and Exercise Settings \ud

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    A three-wave prospective design was used to assess a model of motivation guided by self-determination theory (Ryan & Deci, 2008) spanning the contexts of school physical education (PE) and exercise. The outcome variables examined were health-related quality of life (HRQoL), physical self-concept (PSC), and 4 days of objectively assessed estimates of activity. Secondary school students (n = 494) completed questionnaires at three separate time points and were familiarized with how to use a sealed pedometer. Results of structural equation modeling supported a model in which perceptions of autonomy support from a PE teacher positively predicted PE-related need satisfaction (autonomy, competence, and relatedness). Competence predicted PSC, whereas relatedness predicted HRQoL. Autonomy and competence positively predicted autonomous motivation toward PE, which in turn positively predicted autonomous motivation toward exercise (i.e., 4-day pedometer step count). Autonomous motivation toward exercise positively predicted step count, HRQoL, and PSC. Results of multisample structural equation modeling supported gender invariance. Suggestions for future work are discussed.\ud \u

    Video assisted thoracic surgery for treatment of pneumothorax and lung resections: systematic review of randomised clinical trials

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    <b>Objectives</b> To determine if video assisted thoracic surgery is associated with better clinical outcomes than thoracotomy for three common procedures: surgery for pneumothorax, minor resections, and lobectomy. <b>Design</b> Systematic review of randomised clinical trials. <b>Data sources</b> Medline, Embase, Cochrane database of systematic reviews, Cochrane controlled trials register. Reference lists of relevant articles and reviews. <b>Methods</b> Criteria for inclusion were random allocation of patients and no concurrent use of another experimental medication or device. At least two authors performed and confirmed data abstraction and analyses. Information on quality of trials, demographics, frequency of the events, and numbers randomised were collected. <b>Results</b> 12 trials randomised 670 patients. Video assisted thoracic surgery was associated with shorter length of stay (reduction ranged from 1.0 to 4.2 days) and less pain or use of pain medication than thoracotomy in the five out of seven trials in which the technique was used for pneumothorax or minor lung resection. In the treatment of pneumothorax, video assisted thoracic surgery was associated with substantially fewer recurrences than pleural drainage in two trials (from 20 to 53 events prevented per 100 treated patients). No substantial advantages were observed for video assisted thoracic surgery in lobectomies. <b>Conclusions</b> Video assisted thoracic surgery is associated with better outcomes and seems to have a complication profile comparable with that of thoracotomy for the treatment of pneumothorax and minor resections. As for lobectomy, further studies are needed to determine how it compares with thoracotomy

    The risk of editorial complicity in publishing claims for unproven treatments

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