7,561 research outputs found

    Prospective evaluation of BDProbeTec strand displacement amplification (SDA) system for diagnosis of tuberculosis in non-respiratory and respiratory samples.

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    Nucleic acid amplification techniques (NAATs) have been demonstrated to make significant improvements in the diagnosis of tuberculosis (TB), particularly in the time to diagnosis and the diagnosis of smear-negative TB. The BD ProbeTec strand displacement amplification (SDA) system for the diagnosis of pulmonary and non-pulmonary tuberculosis was evaluated. A total of 689 samples were analysed from patients with clinically suspected TB. Compared with culture, the sensitivity and specificity for pulmonary samples were 98 and 89 %, and against final clinical diagnosis 93 and 92 %, respectively. This assay has undergone limited evaluation for non-respiratory samples and so 331 non-respiratory samples were tested, identifying those specimens that were likely to yield a useful result. These were CSF (n = 104), fine needle aspirates (n = 64) and pus (n = 41). Pleural fluid (n = 47) was identified as a poor specimen. A concern in using the SDA assay was that low-positive samples were difficult to interpret; 7.8 % of specimens fell into this category. Indeed, 64 % of the discrepant results, when compared to final clinical diagnosis, could be assigned as low-positive samples. Specimen type did not predict likelihood of a sample being in the low-positive zone. Although the manufacturers do not describe the concept of a low-positive zone, we have found that it aids clinical diagnosis

    Severe hypothyroidism presenting as cardiac tamponade

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    Corresponding author: Siddharth Patel, Decatur Morgan HospitalWide-spread availability of thyroid stimulating hormone assays and routine screening have resulted in early diagnosis of hypothyroidism. Affordable thyroid hormone replacement therapy has ensured that the prevalence of complications of untreated hypothyroidism including cardiovascular complications remains extremely low. Although pericardial effusion can be seen in hypothyroidism especially in severe cases, cardiac tamponade is uncommon. Cardiac tamponade as the first presenting feature of hypothyroidism is a rarity. A 60-year-old man with a history of hypertension and stroke was brought to the hospital with chief complaints of fall and altered mental status. In the emergency room, he was found to have hypothermia and drowsiness, and his laboratory investigations showed severe hypothyroidism. CT scan of chest revealed a large pericardial effusion and an echocardiogram showed evidence of cardiac tamponade. He was taken for an emergent pericardiotomy with a pericardial window. Pericardial fluid and serum investigations confirmed untreated hypothyroidism as the cause of cardiac tamponade. The patient was treated with aggressive thyroid hormone replacement therapy and his clinical condition improved. This case highlights the importance of screening and treatment of hypothyroidism in at-risk populations. If untreated, hypothyroidism may rarely lead to a potentially life-threatening complication such as cardiac tamponade.Prutha Pathak (Gillings School of Global Public Health, University of North Carolina), Siddharth Patel (Decatur Morgan Hospital), Ashish Basu (Decatur Morgan Hospital), Mc Anto Antony (Medical University of South Carolina/AnMed Campus)Includes bibliographical references

    Diffusion tensor imaging reveals changes in microstructural integrity along compressed nerve roots that correlate with chronic pain symptoms and motor deficiencies in elderly stenosis patients

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    Age-related degenerative changes in the lumbar spine frequently result in nerve root compression causing severe pain and disability. Given the increasing incidence of lumbar spinal disorders in the aging population and the discrepancies between the use of current diagnostic imaging tools and clinical symptoms, novel methods of nerve root assessment are needed. We investigated elderly patients with stenosis at L4-L5 or L5-S1 levels. Diffusion tensor imaging (DTI) was used to quantify microstructure in compressed L5 nerve roots and investigate relationships to clinical symptoms and motor neurophysiology. DTI metrics (i.e. FA, MD, AD and RD) were measured at proximal, mid and distal segments along compressed (i.e. L5) and intact (i.e. L4 or S1) nerve roots. FA was significantly reduced in compressed nerve roots and MD, AD and RD were significantly elevated in the most proximal segment of the nerve root studied. FA was significantly correlated with electrophysiological measures of root function: minimum F-wave latency and peripheral motor conduction time (PMCT). In addition, FA along the compressed root also correlated with leg pain and depression score. There was also a relationship between RD and anxiety, leg pain and disability score and AD correlated with depression score. Taken together, these data show that DTI metrics are sensitive to nerve root compression in patients with stenosis as a result of age-related lumbar degeneration. Critically, they show that the changes in microstructural integrity along compressed L5 nerve roots are closely related to a number of clinical symptoms associated with the development of chronic pain as well as neurophysiological assessments of motor function. These inherent relationships between nerve root damage and phenotype suggest that the use DTI is a promising method as a way to stratify treatment selection and predict outcomes

    From fields to a super-cluster: the role of the environment at z=0.84 with HiZELS

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    At z=0, clusters are primarily populated by red, elliptical and massive galaxies, while blue, spiral and lower-mass galaxies are common in low-density environments. Understanding how and when these differences were established is of absolute importance for our understanding of galaxy formation and evolution, but results at high-z remain contradictory. By taking advantage of the widest and deepest H-alpha narrow-band survey at z=0.84 over the COSMOS and UKIDSS UDS fields, probing a wide range of densities (from poor fields to rich groups and clusters, including a confirmed super-cluster with a striking filamentary structure), we show that the fraction of star-forming galaxies falls continuously from ~40% in fields to approaching 0% in rich groups/clusters. We also find that the median SFR increases with environmental density, at least up to group densities - but only for low and medium mass galaxies, and thus such enhancement is mass-dependent at z~1. The environment also plays a role in setting the faint-end slope (alpha) of the H-alpha luminosity function. Our findings provide a sharper view on galaxy formation and evolution and reconcile previously contradictory results at z~1: stellar mass is the primary predictor of star formation activity, but the environment also plays a major role.Comment: 5 pages, 4 figures, to appear in the proceedings of JENAM 2010 S2: `Environment and the Formation of Galaxies: 30 years later', ASSP, Springe

    Assessment of the nano-mechanical properties of healthy and atherosclerotic coronary arteries by atomic force microscopy.

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    Nano-indentation techniques might be better equipped to assess the heterogeneous material properties of plaques than macroscopic methods but there are no bespoke protocols for this kind of material testing for coronary arteries. Therefore, we developed a measurement protocol to extract mechanical properties from healthy and atherosclerotic coronary artery tissue sections. Young's modulus was derived from force-indentation data. Metrics of collagen fibre density were extracted from the same tissue, and the local material properties were co-registered to the local collagen microstructure with a robust framework. The locations of the indentation were retrospectively classified by histological category (healthy, plaque, lipid-rich, fibrous cap) according to Picrosirius Red stain and adjacent Hematoxylin & Eosin and Oil-Red-O stains. Plaque tissue was softer (p < 0.001) than the healthy coronary wall. Areas rich in collagen within the plaque (fibrous cap) were significantly (p < 0.001) stiffer than areas poor in collagen/lipid-rich, but less than half as stiff as the healthy coronary media. Young's moduli correlated (Pearson's ρ = 0.53, p < 0.05) with collagen content. Atomic force microscopy (AFM) is capable of detecting tissue stiffness changes related to collagen density in healthy and diseased cardiovascular tissue. Mechanical characterization of atherosclerotic plaques with nano-indentation techniques could refine constitutive models for computational modelling

    Point-Spread-Function-Aware Slice-to-Volume Registration: Application to Upper Abdominal MRI Super-Resolution

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    MR image acquisition of moving organs remains challenging despite the advances in ultra-fast 2D MRI sequences. Post-acquisition techniques have been proposed to increase spatial resolution a posteriori by combining acquired orthogonal stacks into a single, high-resolution (HR) volume. Current super-resolution techniques classically rely on a two-step procedure. The volumetric reconstruction step leverages a physical slice acquisition model. However, the motion correction step typically neglects the point spread function (PSF) information. In this paper, we propose a PSF-aware slice-to-volume registration approach and, for the first time, demonstrate the potential benefit of Super-Resolution for upper abdominal imaging. Our novel reconstruction pipeline takes advantage of different MR acquisitions clinically used in routine MR cholangiopancreatography studies to guide the registration. On evaluation of clinically relevant image information, our approach outperforms state-of-the-art reconstruction toolkits in terms of visual clarity and preservation of raw data information. Overall, we achieve promising results towards replacing currently required CT scans

    Isolated cardiophrenic angle node metastasis from ovarian primary. report of two cases

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    Ovarian cancer is the most lethal gynaecologic malignancy. It usually spreads out of the abdomen involving thoraco-abdominal organs and serosal surface. This disease is poorly curable and surgery, at early stage, is supposed to achieve the best survival outcome. In systemic dissemination, chemiotherapy is indicated, sometimes with neoadjuvant aim. The most common clinical expressions of advanced ovarian carcinoma are multiple adenopathy, neoplastic pleuritis, peritoneal seeding and distant metastasis, mainly hepatic and pulmonary. Isolated adenopathy of the mediastinum is rare and isolated bilateral have never been described before. We report two cases of isolated bilateral cardiophrenic angle lymphnode metastasis from ovarian carcinoma, without peritoneal and pleural involvement. Both patients were successfully resected through minimally invasive thoracic surgery. About the role of surgery, few data are available but survival seems to be longer after resection thus, more investigation is required to make the indication to surgery more appropriate in advanced cases
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