5,634 research outputs found

    Gauge theories as a geometrical issue of a Kaluza-Klein framework

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    We present a geometrical unification theory in a Kaluza-Klein approach that achieve the geometrization of a generic gauge theory bosonic component. We show how it is possible to derive the gauge charge conservation from the invariance of the model under extra-dimensional translations and to geometrize gauge connections for spinors, thus we can introduce the matter just by free spinorial fields. Then, we present the applications to i)a pentadimensional manifold V4⊗S1V^{4}\otimes S^{1}, so reproducing the original Kaluza-Klein theory, unless some extensions related to the rule of the scalar field contained in the metric and the introduction of matter by spinors with a phase dependence from the fifth coordinate, ii)a seven-dimensional manifold V4⊗S1⊗S2V^{4}\otimes S^{1}\otimes S^{2}, in which we geometrize the electro-weak model by introducing two spinors for any leptonic family and quark generation and a scalar field with two components with opposite hypercharge, responsible of spontaneous symmetry breaking.Comment: 37 pages, no figure

    World Allergy Organization (WAO) Diagnosis and Rationale for Action against Cow's Milk Allergy (DRACMA) Guidelines update - IV - A quality appraisal with the AGREE II instrument

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    Since the publication of The World Allergy Organization (WAO) Diagnosis and Rationale for Action against Cow's Milk Allergy (DRACMA) Guidelines in 2010, a number of other guidelines, expert opinions, and position papers relating to the management of cow's milk allergy (CMA) have been published. We aimed to systematically review the quality of the guidelines on CMA diagnosis and management in children and/or adults published between 2010 and 2020

    How are "teaching the teachers" courses in evidence based medicine evaluated? A systematic review

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    Background Teaching of evidence-based medicine (EBM) has become widespread in medical education. Teaching the teachers (TTT) courses address the increased teaching demand and the need to improve effectiveness of EBM teaching. We conducted a systematic review of assessment tools for EBM TTT courses. To summarise and appraise existing assessment methods for teaching the teachers courses in EBM by a systematic review. Methods We searched PubMed, BioMed, EmBase, Cochrane and Eric databases without language restrictions and included articles that assessed its participants. Study selection and data extraction were conducted independently by two reviewers. Results Of 1230 potentially relevant studies, five papers met the selection criteria. There were no specific assessment tools for evaluating effectiveness of EBM TTT courses. Some of the material available might be useful in initiating the development of such an assessment tool. Conclusion There is a need for the development of educationally sound assessment tools for teaching the teachers courses in EBM, without which it would be impossible to ascertain if such courses have the desired effect

    AIM2 recognizes cytosolic dsDNA and forms a caspase-1-activating inflammasome with ASC

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    The innate immune system senses nucleic acids by germline-encoded pattern recognition receptors. RNA is sensed by Toll-like receptor members TLR3, TLR7 and TLR8, or by the RNA helicases RIG-I (also known as DDX58) and MDA-5 (IFIH1). Little is known about sensors for cytoplasmic DNA that trigger antiviral and/or inflammatory responses. The best characterized of these responses involves activation of the TANK-binding kinase (TBK1)-interferon regulatory factor 3 (IRF3) signalling axis to trigger transcriptional induction of type I interferon genes. A second, less well-defined pathway leads to the activation of an 'inflammasome' that, via caspase-1, controls the catalytic cleavage of the pro-forms of the cytokines IL1beta and IL18 (refs 6, 7). Using mouse and human cells, here we identify the PYHIN (pyrin and HIN domain-containing protein) family member absent in melanoma 2 (AIM2) as a receptor for cytosolic DNA, which regulates caspase-1. The HIN200 domain of AIM2 binds to DNA, whereas the pyrin domain (but not that of the other PYHIN family members) associates with the adaptor molecule ASC (apoptosis-associated speck-like protein containing a caspase activation and recruitment domain) to activate both NF-kappaB and caspase-1. Knockdown of Aim2 abrogates caspase-1 activation in response to cytoplasmic double-stranded DNA and the double-stranded DNA vaccinia virus. Collectively, these observations identify AIM2 as a new receptor for cytoplasmic DNA, which forms an inflammasome with the ligand and ASC to activate caspase-1

    CPAP as treatment of sleep apnea after stroke: A meta-analysis of randomized trials.

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    OBJECTIVE To perform a systematic review and meta-analysis of randomized controlled trials (RCTs) examining the effectiveness of continuous positive airway pressure (CPAP) in stroke patients with sleep disordered breathing (SDB). METHODS In a systematic literature search of electronic databases (MEDLINE, Embase, and the Cochrane Library) from 1980 to November 2016, we identified RCTs that assessed CPAP compared to standard care or sham CPAP in adult patients with stroke or TIA with SDB. Mean CPAP use, odds ratios (ORs), and standardized mean differences (SMDs) were calculated. The prespecified outcomes were adherence to CPAP, neurologic improvement, adverse events, new vascular events, and death. RESULTS Ten RCTs (564 participants) with CPAP as intervention were included. Two studies compared CPAP with sham CPAP; 8 compared CPAP with usual care. Mean CPAP use across the trials was 4.53 hours per night (95% confidence interval [CI] 3.97-5.08). The OR of dropping out with CPAP was 1.83 (95% CI 1.05-3.21,= 0.033). The combined analysis of the neurofunctional scales (NIH Stroke Scale and Canadian Neurological Scale) showed an overall neurofunctional improvement with CPAP (SMD 0.5406, 95% CI 0.0263-1.0548) but with a considerable heterogeneity (= 78.9%,= 0.0394) across the studies. Long-term survival was improved with CPAP in 1 trial. CONCLUSION CPAP use after stroke is acceptable once the treatment is tolerated. The data indicate that CPAP might be beneficial for neurologic recovery, which justifies larger RCTs

    Setting clinical performance specifications to develop and evaluate biomarkers for clinical use

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    Background: Biomarker discovery studies often claim ‘promising’ findings, motivating further studies and marketing as medical tests. Unfortunately, the patient benefits promised are often inadequately explained to guide further evaluation, and few biomarkers have translated to improved patient care. We present a practical guide for setting minimum clinical performance specifications to strengthen clinical performance study design and interpretation. Methods: We developed a step-by-step approach using test evaluation and decision-analytic frameworks and present with illustrative examples. Results: We define clinical performance specifications as a set of criteria that quantify the clinical performance a new test must attain to allow better health outcomes than current practice. We classify the proposed patient benefits of a new test into three broad groups and describe how to set minimum clinical performance at the level where the potential harm of false-positive and false-negative results does not outweigh the benefits. (1) For add-on tests proposed to improve disease outcomes by improving detection, define an acceptable trade-off for false-positive versus true-positive results; (2) for triage tests proposed to reduce unnecessary tests and treatment by ruling out disease, define an acceptable risk of false-negatives as a safety threshold; (3) for replacement tests proposed to provide other benefits, or reduce costs, without compromising accuracy, use existing tests to benchmark minimum accuracy levels. Conclusions: Researchers can follow these guidelines to focus their study objectives and to define statistical hypotheses and sample size requirements. This way, clinical performance studies will allow conclusions about whether test performance is sufficient for intended use

    Frequency and evolution of sleep-wake disturbances after ischemic stroke: A 2-year prospective study of 437 patients.

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    OBJECTIVE In the absence of systematic and longitudinal data, this study prospectively assessed both frequency and evolution of sleep-wake disturbances (SWD) after stroke. METHODS In 437 consecutively recruited patients with ischemic stroke or transient ischemic attack (TIA), stroke characteristics and outcome were assessed within the 1st week and 3.2 ± 0.3 years (M±SD) after the acute event. SWD were assessed by interview and questionnaires at 1 and 3 months as well as 1 and 2 years after the acute event. Sleep disordered breathing (SDB) was assessed by respirography in the acute phase and repeated in one fifth of the participants 3 months and 1 year later. RESULTS Patients (63.8% male, 87% ischemic stroke and mean age 65.1 ± 13.0 years) presented with mean NIHSS-score of 3.5 ± 4.5 at admission. In the acute phase, respiratory event index was >15/h in 34% and >30/h in 15% of patients. Over the entire observation period, the frequencies of excessive daytime sleepiness (EDS), fatigue and insomnia varied between 10-14%, 22-28% and 20-28%, respectively. Mean insomnia and EDS scores decreased from acute to chronic stroke, whereas restless legs syndrome (RLS) percentages (6-9%) and mean fatigue scores remained similar. Mean self-reported sleep duration was enhanced at acute stroke (month 1: 07:54 ± 01:27h) and decreased at chronic stage (year 2: 07:43 ± 01:20h). CONCLUSIONS This study documents a high frequency of SDB, insomnia, fatigue and a prolonged sleep duration after stroke/TIA, which can persist for years. Considering the negative effects of SWD on physical, brain and mental health these data suggest the need for a systematic assessment and management of post-stroke SWD

    Delivering safe and effective test-result communication, management and follow-up : a mixed-methods study protocol

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    Introduction: The failure to follow-up pathology and medical imaging test results poses patient-safety risks which threaten the effectiveness, quality and safety of patient care. The objective of this project is to: (1) improve the effectiveness and safety of test-result management through the establishment of clear governance processes of communication, responsibility and accountability; (2) harness health information technology (IT) to inform and monitor test-result management; (3) enhance the contribution of consumers to the establishment of safe and effective test-result management systems. Methods and analysis: This convergent mixed-methods project triangulates three multistage studies at seven adult hospitals and one paediatric hospital in Australia. Study 1 adopts qualitative research approaches including semistructured interviews, focus groups and ethnographic observations to gain a better understanding of test-result communication and management practices in hospitals, and to identify patient-safety risks which require quality-improvement interventions. Study 2 analyses linked sets of routinely collected healthcare data to examine critical test-result thresholds and test-result notification processes. A controlled before-and-after study across three emergency departments will measure the impact of interventions (including the use of IT) developed to improve the safety and quality of test-result communication and management processes. Study 3 adopts a consumer-driven approach, including semistructured interviews, and the convening of consumer-reference groups and community forums. The qualitative data will identify mechanisms to enhance the role of consumers in test-management governance processes, and inform the direction of the research and the interpretation of findings. Ethics and dissemination: Ethical approval has been granted by the South Eastern Sydney Local Health District Human Research Ethics Committee and Macquarie University. Findings will be disseminated in academic, industry and consumer journals, newsletters and conferences

    Distribution of Alarin Immunoreactivity in the Mouse Brain

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    Alarin is a 25 amino acid peptide that belongs to the galanin peptide family. It is derived from the galanin-like peptide gene by a splice variant, which excludes exon 3. Alarin was first identified in gangliocytes of neuroblastic tumors and later shown to have a vasoactive function in the skin. Recently, alarin was demonstrated to stimulate food intake as well as the hypothalamic–pituitary–gonadal axis in rodents, suggesting that it might be a neuromodulatory peptide in the brain. However, the individual neurons in the central nervous system that express alarin have not been identified. Here, we determined the distribution of alarin-like immunoreactivity (alarin-LI) in the adult murine brain. The specificity of the antibody against alarin was demonstrated by the absence of labeling after pre-absorption of the antiserum with synthetic alarin peptide and in transgenic mouse brains lacking neurons expressing the GALP gene. Alarin-LI was observed in different areas of the murine brain. A high intensity of alarin-LI was detected in the accessory olfactory bulb, the medial preoptic area, the amygdala, different nuclei of the hypothalamus such as the arcuate nucleus and the ventromedial hypothalamic nucleus, the trigeminal complex, the locus coeruleus, the ventral chochlear nucleus, the facial nucleus, and the epithelial layer of the plexus choroideus. The distinct expression pattern of alarin in the adult mouse brain suggests potential functions in reproduction and metabolism

    Predicting for activity of second-line trastuzumab-based therapy in her2-positive advanced breast cancer

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    <p>Abstract</p> <p>Background</p> <p>In Her2-positive advanced breast cancer, the upfront use of trastuzumab is well established. Upon progression on first-line therapy, patients may be switched to lapatinib. Others however remain candidates for continued antibody treatment (treatment beyond progression). Here, we aimed to identify factors predicting for activity of second-line trastuzumab-based therapy.</p> <p>Methods</p> <p>Ninety-seven patients treated with > 1 line of trastuzumab-containing therapy were available for this analysis. Her2-status was determined by immunohistochemistry and re-analyzed by FISH if a score of 2+ was gained. Time to progression (TTP) on second-line therapy was defined as primary study endpoint. TTP and overall survival (OS) were estimated using the Kaplan-Meier product limit method. Multivariate analyses (Cox proportional hazards model, multinomial logistic regression) were applied in order to identify factors associated with TTP, response, OS, and incidence of brain metastases. <it>p </it>values < 0.05 were considered to indicate statistical significance.</p> <p>Results</p> <p>Median TTP on second-line trastuzumab-based therapy was 7 months (95% CI 5.74-8.26), and 8 months (95% CI 6.25-9.74) on first-line, respectively (n.s.). In the multivariate models, none of the clinical or histopthological features could reliably predict for activity of second-line trastuzumab-based treatment. OS was 43 months suggesting improved survival in patients treated with trastuzumab in multiple-lines. A significant deterioration of cardiac function was observed in three patients; 40.2% developed brain metastases while on second-line trastuzumab or thereafter.</p> <p>Conclusion</p> <p>Trastuzumab beyond progression showed considerable activity. None of the variables investigated correlated with activity of second-line therapy. In order to predict for activity of second-line trastuzumab, it appears necessary to evaluate factors known to confer trastuzumab-resistance.</p
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