300 research outputs found

    Novel Distances for Dollo Data

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    We investigate distances on binary (presence/absence) data in the context of a Dollo process, where a trait can only arise once on a phylogenetic tree but may be lost many times. We introduce a novel distance, the Additive Dollo Distance (ADD), which is consistent for data generated under a Dollo model, and show that it has some useful theoretical properties including an intriguing link to the LogDet distance. Simulations of Dollo data are used to compare a number of binary distances including ADD, LogDet, Nei Li and some simple, but to our knowledge previously unstudied, variations on common binary distances. The simulations suggest that ADD outperforms other distances on Dollo data. Interestingly, we found that the LogDet distance performs poorly in the context of a Dollo process, which may have implications for its use in connection with conditioned genome reconstruction. We apply the ADD to two Diversity Arrays Technology (DArT) datasets, one that broadly covers Eucalyptus species and one that focuses on the Eucalyptus series Adnataria. We also reanalyse gene family presence/absence data on bacteria from the COG database and compare the results to previous phylogenies estimated using the conditioned genome reconstruction approach

    Comparison of fixed cell-based assay to radioimmunoprecipitation assay for acetylcholine receptor antibody detection in myasthenia gravis

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    Objective: To compare specificity and sensitivity of a commercially available fixed cell-based assay (F-CBA) to radioimmunoprecipitation assay (RIPA) for acetylcholine receptor antibody (anti-AChR) detection in myasthenia gravis (MG). Methods: In this retrospective diagnostic cohort study we reviewed the clinical information of suspected MG patients evaluated at the London Health Sciences Centre MG clinic who had anti-AChR RIPA and then F-CBA performed, in order to classify them as MG or non-MG. Classification of each patient as anti-AChR F-CBA-negative/positive, RIPA-negative/positive, and MG/non-MG permitted specificity and sensitivity calculations for each assay. Results: Six-hundred-eighteen patients were included in study analysis. The median patient age at time of sample collection was 45.8 years (range: 7.5–87.5 years) and 312/618 (50.5%) were female. Of 618 patients, 395 (63.9%) were classified as MG. Specificity of both F-CBA and RIPA was excellent (99.6% vs. 100%, P \u3e 0.99). One F-CBA-positive patient was classified as non-MG, although in retrospect ocular MG with functional overlay was challenging to exclude. Sensitivity of F-CBA was significantly higher than RIPA (76.7% vs. 72.7%, P = 0.002). Overall, 20/97 (21%) otherwise seronegative MG (SNMG) patients after RIPA evaluation had anti-AChR detected by F-CBA. Conclusions: In our study anti-AChR F-CBA and RIPA both had excellent specificity, while F-CBA had 4% higher sensitivity for MG and detected anti-AChR in 21% of SNMG patients. Our findings indicate that F-CBA is a viable alternative to RIPA for anti-AChR detection. Prospective studies comparing F-CBA, RIPA and L-CBA are needed to determine optimal anti-AChR testing algorithms in MG

    Prognosis of West Nile virus associated acute flaccid paralysis: a case series

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    Introduction: Little is known about the long-term health related quality of life outcomes in patients with West Nile virus associated acute flaccid paralysis. We describe the quality of life scores of seven patients with acute flaccid paralysis who presented to hospital between 2003 and 2006, and were followed for up to two years. Case presentations: Between 2003 and 2006, 157 symptomatic patients with West Nile virus were enrolled in a longitudinal cohort study of West Nile virus in Canada. Seven patients (4%) had acute flaccid paralysis. The firs

    "A randomized trial of initiation of chronic non-invasive mechanical ventilation at home vs in-hospital in patients with Neuromuscular Disease and thoracic cage disorder":The Dutch Homerun Trial

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    Background: There is an increasing demand for home mechanical ventilation (HMV) in patients with chronic respiratory insufficiency. At present, noninvasive ventilation is exclusively initiated in a clinical setting at all four centers for HMV in the Netherlands. In addition to its high societal costs and patient discomfort, commencing HMV is often delayed because of a lack of hospital bed capacity. Research Question: Is HMV initiation at home, using a telemonitoring approach, noninferior to in-hospital initiation in a nationwide study? Study Design and Methods: We conducted a nationwide, randomized controlled noninferiority trial, in which every HMV center recruited 24 patients (home [n = 12] vs hospital [n = 12]) with a neuromuscular disease or thoracic cage disorder, all with an indication to start HMV. Change in arterial CO 2 (PaCO 2) over a 6-month period was considered the primary outcome, and quality of life and costs were assessed as secondary outcomes. Results: A total of 96 patients were randomized, most of them diagnosed with neuromuscular disease. We found a significant improvement in PaCO 2 within both groups (home: from 6.1 to 5.6 kPa [P <.01]; hospital: from 6.3 to 5.6 kPa [P <.01]), with no significant differences between groups. Health-related quality of life showed significant improvement on various subscales; however, no significant differences were observed between the home and hospital groups. From a societal perspective, a cost reduction of more than €3,200 (3,793)perpatientwasevidentinthehomegroup.Interpretation:Thisnationwide,multicenterstudyshowsthatHMVinitiationathomeisnoninferiortohospitalinitiation,asitshowsthesameimprovementingasexchangeandhealthrelatedqualityoflife.Infact,fromapatientsperspective,itmightevenbeamoreattractiveapproach.Inaddition,startingathomesavesover3,200(3,793) per patient was evident in the home group. Interpretation: This nationwide, multicenter study shows that HMV initiation at home is noninferior to hospital initiation, as it shows the same improvement in gas exchange and health-related quality of life. In fact, from a patient's perspective, it might even be a more attractive approach. In addition, starting at home saves over €3,200 (3,793) per patient over a 6-month period. Trial Registry: ClinicalTrials.gov; No.: NCT03203577; URL: www.clinicaltrials.gov

    Stereoselective synthesis of tetrahydroindolizines via catalytic formation of pyridinium ylides from diazo compounds

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    Commercially available iron (III) and copper (I) complexes catalyze new multicomponent cycloadditions between diazo compounds, pyridines and electrophilic alkenes to give alkaloid-inspired tetrahydroindolizidines in high yields and diastereoselectivities. Hitherto, catalytic formation of versatile pyridinium ylides from metal carbenes has been poorly developed; the broad utility demonstrated herein sets the stage for invention of further multicomponent reactions in future

    International Consensus Guidance for Management of Myasthenia Gravis

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    To update the 2016 formal consensus-based guidance for the management of myasthenia gravis (MG) based on the latest evidence in the literature. In October 2013, the Myasthenia Gravis Foundation of America appointed a Task Force to develop treatment guidance for MG, and a panel of 15 international experts was convened. The RAND/UCLA appropriateness method was used to develop consensus recommendations pertaining to 7 treatment topics. In February 2019, the international panel was reconvened with the addition of one member to represent South America. All previous recommendations were reviewed for currency, and new consensus recommendations were developed on topics that required inclusion or updates based on the recent literature. Up to 3 rounds of anonymous e-mail votes were used to reach consensus, with modifications to recommendations between rounds based on the panel input. A simple majority vote (80% of panel members voting "yes") was used to approve minor changes in grammar and syntax to improve clarity. The previous recommendations for thymectomy were updated. New recommendations were developed for the use of rituximab, eculizumab, and methotrexate as well as for the following topics: early immunosuppression in ocular MG and MG associated with immune checkpoint inhibitor treatment. This updated formal consensus guidance of international MG experts, based on new evidence, provides recommendations to clinicians caring for patients with MG worldwide

    International consensus guidance for management of myasthenia gravis

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    Altres ajuts: Supported by a grant from the Myasthenia Gravis Foundation of America (MGFA).To develop formal consensus-based guidance for the management of myasthenia gravis (MG). In October 2013, the Myasthenia Gravis Foundation of America appointed a Task Force to develop treatment guidance for MG, and a panel of 15 international experts was convened. The RAND/UCLA appropriateness methodology was used to develop consensus guidance statements. Definitions were developed for goals of treatment, minimal manifestations, remission, ocular MG, impending crisis, crisis, and refractory MG. An in-person panel meeting then determined 7 treatment topics to be addressed. Initial guidance statements were developed from literature summaries. Three rounds of anonymous e-mail votes were used to attain consensus on guidance statements modified on the basis of panel input. Guidance statements were developed for symptomatic and immunosuppressive treatments, IV immunoglobulin and plasma exchange, management of impending and manifest myasthenic crisis, thymectomy, juvenile MG, MG associated with antibodies to muscle-specific tyrosine kinase, and MG in pregnancy. This is an international formal consensus of MG experts intended to be a guide for clinicians caring for patients with MG worldwide

    Epidemiology's Continuing Contribution to Public Health: The Power of “Then and Now”

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    The 47th annual meeting of the Society for Epidemiologic Research hosted 17 invited speakers charged by the Executive Committee with presenting some of the many ways that epidemiologists have improved the health of the general population. There were 9 “Then and Now” sessions that were structured to focus on how early epidemiologists overcame research hurdles and advanced health through innovative strategies. For most topics, a longstanding expert was paired with an excellent contemporary epidemiologist working in the area, and both were given the freedom to deliver an integrated story about epidemiology's temporal role in protecting and promoting public health. Epidemiologic discoveries in cardiovascular, cancer, and perinatal epidemiology were discussed on day 1, followed by discussions of accomplishments in reducing exposures that adversely impact health (nutrition, environment/occupation, and tobacco use) on day 2. Topics with relevancy for many aspects of epidemiology were presented on day 3, including infectious diseases, social forces, and causal thinking in epidemiologic research. Given the large number of outstanding senior and junior epidemiologists that attended the meeting, choosing speakers was a unique challenge. What became evident from all sessions was the passion that epidemiologists have for population health, tempered with concerns for remaining true to epidemiologic principles, the timely adoption of innovative methods, and the responsible interpretation of research findings
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