1,012 research outputs found

    Performance of the 12-item WHODAS 2.0 in prodromal Huntington disease

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    ACKNOWLEDGEMENTS We thank the PREDICT-HD sites, the study participants, the National Research Roster for Huntington Disease Patients and Families, the Huntington’s Disease Society of America and the Huntington Study Group. This publication was supported by the National Center for Advancing Translational Sciences, and the National Institutes of Health (NIH), through Grant 2 UL1 TR000442-06. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. This research is supported by the National Institutes of Health, National Institute of Neurological Disorders and Stroke (5R01NS040068) awarded to Dr Paulsen, CHDI Foundation, Inc (A3917) awarded to Dr Paulsen, Cognitive and Functional Brain Changes in Preclinical Huntington’s Disease (HD) (5R01NS054893) awarded to Dr Paulsen, 4D Shape Analysis for Modeling Spatiotemporal Change Trajectories in Huntington’s (1U01NS082086), Functional Connectivity in Premanifest Huntington’s Disease (1U01NS082083), and Basal Ganglia Shape Analysis and Circuitry in Huntington’s Disease (1U01NS082085).Peer reviewedPublisher PD

    Gill Damage to Atlantic Salmon (Salmo salar) Caused by the Common Jellyfish (Aurelia aurita) under Experimental Challenge

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    Peer-reviewed. Copyright © 2011 E.J. Baxter et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: Over recent decades jellyfish have caused fish kill events and recurrent gill problems in marine-farmed salmonids. Common jellyfish (Aurelia spp.) are among the most cosmopolitan jellyfish species in the oceans, with populations increasing in many coastal areas. The negative interaction between jellyfish and fish in aquaculture remains a poorly studied area of science. Thus, a recent fish mortality event in Ireland, involving Aurelia aurita, spurred an investigation into the effects of this jellyfish on marine-farmed salmon. Methodology/Principal Findings: To address the in vivo impact of the common jellyfish (A. aurita) on salmonids, we exposed Atlantic salmon (Salmo salar) smolts to macerated A. aurita for 10 hrs under experimental challenge. Gill tissues of control and experimental treatment groups were scored with a system that rated the damage between 0 and 21 using a range of primary and secondary parameters. Our results revealed that A. aurita rapidly and extensively damaged the gills of S. salar, with the pathogenesis of the disorder progressing even after the jellyfish were removed. After only 2 hrs of exposure, significant multi-focal damage to gill tissues was apparent. The nature and extent of the damage increased up to 48 hrs from the start of the challenge. Although the gills remained extensively damaged at 3 wks from the start of the challenge trial, shortening of the gill lamellae and organisation of the cells indicated an attempt to repair the damage suffered. Conclusions: Our findings clearly demonstrate that A. aurita can cause severe gill problems in marine-farmed fish. With aquaculture predicted to expand worldwide and evidence suggesting that jellyfish populations are increasing in some areas, this threat to aquaculture is of rising concern as significant losses due to jellyfish could be expected to increase in the future

    The transition between stochastic and deterministic behavior in an excitable gene circuit

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    We explore the connection between a stochastic simulation model and an ordinary differential equations (ODEs) model of the dynamics of an excitable gene circuit that exhibits noise-induced oscillations. Near a bifurcation point in the ODE model, the stochastic simulation model yields behavior dramatically different from that predicted by the ODE model. We analyze how that behavior depends on the gene copy number and find very slow convergence to the large number limit near the bifurcation point. The implications for understanding the dynamics of gene circuits and other birth-death dynamical systems with small numbers of constituents are discussed.Comment: PLoS ONE: Research Article, published 11 Apr 201

    Knowledge, Perceptions and Information about Hormone Therapy (HT) among Menopausal Women: A Systematic Review and Meta-Synthesis

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    BACKGROUND: The use of hormone therapy (HT) by menopausal women has declined since the Women's Health Initiative randomized trial (WHI) in 2002 demonstrated important harms associated with long-term use. However, how this information has influenced women's knowledge and attitudes is uncertain. We aimed to evaluate the attitudes and perceptions towards HT use, as well as specific concerns and information sources on HT since the WHI trial. METHOD/RESULTS: We did a systematic review to assess the attitudes and knowledge towards HT in women, and estimate the magnitude of the issue by pooling across the studies. Using meta-synthesis methods, we reviewed qualitative studies and surveys and performed content analysis on the study reports. We pooled quantitative studies using a random-effects meta-analysis. We analyzed 11 qualitative studies (n = 566) and 27 quantitative studies (n = 39251). Positive views on HT included climacteric symptom control, prevention of osteoporosis and a perceived improvement in quality of life. Negative factors reported included concerns about potential harmful effects, particularly cancer risks. Sources of information included health providers, media, and social contact. By applying a meta-synthesis approach we demonstrate that these findings are broadly applicable across large groups of patients. CONCLUSIONS: Although there are clear hazards associated with long-term HT use, many women view HT favorably for climacteric symptom relief. Media, as a source of information, is often valued as equivalent to health providers

    Survival End Points for Huntington Disease Trials Prior to a Motor Diagnosis

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    IMPORTANCE: Predictive genetic testing in Huntington disease (HD) enables therapeutic trials in HTT gene expansion mutation carriers prior to a motor diagnosis. Progression-free survival (PFS) is the composite of a motor diagnosis or a progression event, whichever comes first. OBJECTIVE: To determine if PFS provides feasible sample sizes for trials with mutation carriers who have not yet received a motor diagnosis. DESIGN, SETTING AND PARTICIPANTS: This study uses data from the 2-phase, longitudinal cohort studies called Track and from a longitudinal cohort study called the Cooperative Huntington Observational Research Trial (COHORT). Track had 167 prediagnosis mutation carriers and 156 noncarriers, whereas COHORT had 366 prediagnosis mutation carriers and noncarriers. Track studies were conducted at 4 sites in 4 countries (Canada, France, England, and the Netherlands) from which data were collected from January 17, 2008, through November 17, 2014. The COHORT was conducted at 38 sites in 3 countries (Australia, Canada, and the United States) from which data were collected from February 14, 2006, through December 31, 2009. Results from the Track data were externally validated with data from the COHORT. The required sample size was estimated for a 2-arm prediagnosis clinical trial. Data analysis took place from May 1, 2016, to June 10, 2017. MAIN OUTCOMES AND MEASURES: The primary end point is PFS. Huntington disease progression events are defined for the Unified Huntington's Disease Rating Scale total motor score, total functional capacity, symbol digit modalities test, and Stroop word test. RESULTS: Of Track’s 167 prediagnosis mutation carriers, 93 (55.6%) were women, and the mean (SD) age was 40.06 (8.92) years; of the 156 noncarriers, 87 (55.7%) were women, and the mean (SD) age was 45.58 (10.30) years. Of the 366 COHORT participants, 229 (62.5%) were women and the mean (SD) age was 42.21 (12.48) years. The PFS curves of the Track mutation carriers showed good external validity with the COHORT mutation carriers after adjusting for initial progression. For required sample size, PFS with a motor diagnosis or total motor score progression required about 4 times fewer participants than a motor diagnosis alone. Including additional cognitive progression events further reduced the number. For example, a 3-year trial with 10% attrition and a treatment effect of 50% requires a total of 661 with motor diagnosis as the survival end point but only 177 with a total motor score PFS. CONCLUSIONS AND RELEVANCE: Reasonably sized prediagnosis Huntington disease trials can be planned with PFS, and there is evidence of generalizability of this approach

    Atmospheric oxygen regulation at low Proterozoic levels by incomplete oxidative weathering of sedimentary organic carbon

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    It is unclear why atmospheric oxygen remained trapped at low levels for more than 1.5 billion years following the Paleoproterozoic Great Oxidation Event. Here, we use models for erosion, weathering and biogeochemical cycling to show that this can be explained by the tectonic recycling of previously accumulated sedimentary organic carbon, combined with the oxygen sensitivity of oxidative weathering. Our results indicate a strong negative feedback regime when atmospheric oxygen concentration is of order pO2∼0.1 PAL (present atmospheric level), but that stability is lost at pO2<0.01 PAL. Within these limits, the carbonate carbon isotope (δ13C) record becomes insensitive to changes in organic carbon burial rate, due to counterbalancing changes in the weathering of isotopically light organic carbon. This can explain the lack of secular trend in the Precambrian δ13C record, and reopens the possibility that increased biological productivity and resultant organic carbon burial drove the Great Oxidation Event

    The treatment of migraines and tension-type headaches with intravenous and oral niacin (nicotinic acid): systematic review of the literature

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    BACKGROUND: Migraine and tension-type headaches impose a tremendous economic drain upon the healthcare system. Intravenous and oral niacin has been employed in the treatment of acute and chronic migraine and tension-type headaches, but its use has not become part of contemporary medicine, nor have there been randomized controlled trials further assessing this novel treatment. We aimed to systematically review the evidence of using intravenous and/or oral niacin as a treatment for migraine headaches, tension-type headaches, and for headaches of other etiologic types. METHODS: We searched English and non-English language articles in the following databases: MEDLINE (1966–February 2004), AMED (1995–February 2004) and Alt HealthWatch (1990–February 2004). RESULTS: Nine articles were found to meet the inclusion criteria and were included in this systematic review. Hypothetical reasons for niacin's effectiveness include its vasodilatory properties, and its ability to improve mitochondrial energy metabolism. Important side effects of niacin include flushing, nausea and fainting. CONCLUSION: Although niacin's mechanisms of action have not been substantiated from controlled clinical trials, this agent may have beneficial effects upon migraine and tension-type headaches. Adequately designed randomized trials are required to determine its clinical implications
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