1,806 research outputs found

    Signal reconstruction of pulmonary vein recordings using a phenomenological mathematical model: Application to pulmonary vein isolation therapy

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    This is the final version of the article. Available from Frontiers Media via the DOI in this record.Atrial fibrillation (AF), the most prevalent cardiac arrhythmia, is commonly initiated by ectopic beats originating from a small myocardial sleeve extending over the pulmonary veins. Pulmonary vein isolation therapy attempts to isolate the pulmonary veins from the left atrium by ablating tissue, commonly by using radiofrequency ablation. During this procedure, the cardiologist records electrical activity using a lasso catheter, and the activation pattern recorded is used as a guide toward which regions to ablate. However, poor contact between electrode and tissue ca n lead to important regions of electrical activity not being recorded in clinic. We reproduce these signals through the use of a phenomenological model of the cardiac action potential on a cylinder, which we fit to post-AF atrial cells, and model the bipolar electrodes of the lasso catheter by an approximation of the surface potential. The resulting activation pattern is validated by direct comparison with those of clinical recordings. A potential application of the model is to reconstruct the missing electrical activity, minimizing the impact of the information loss on the clinical procedure, and we present results to demonstrate this.JT acknowledges the generous support of the Wellcome Trust via Institutional Strategic Support Award (WT105618MA). JT further acknowledges financial support of the EPSRC via grant EP/N014391/1. HG acknowledges the financial support of the University of Exeter

    Genetic evidence that higher central adiposity causes gastro-oesophageal reflux disease: a Mendelian-randomization study

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    Background: Gastro-oesophageal reflux disease (GORD) is associated with multiple risk factors but determining causality is difficult. We used a genetic approach [Mendelian randomization (MR)] to identify potential causal modifiable risk factors for GORD. Methods: We used data from 451 097 European participants in the UK Biobank and defined GORD using hospital-defined ICD10 and OPCS4 codes and self-report data (N = 41 024 GORD cases). We tested observational and MR-based associations between GORD and four adiposity measures [body mass index (BMI), waist-hip ratio (WHR), a metabolically favourable higher body-fat percentage and waist circumference], smoking status, smoking frequency and caffeine consumption. Results: Observationally, all adiposity measures were associated with higher odds of GORD. Ever and current smoking were associated with higher odds of GORD. Coffee consumption was associated with lower odds of GORD but, among coffee drinkers, more caffeinated-coffee consumption was associated with higher odds of GORD. Using MR, we provide strong evidence that higher WHR and higher WHR adjusted for BMI lead to GORD. There was weak evidence that higher BMI, body-fat percentage, coffee drinking or smoking caused GORD, but only the observational effects for BMI and body-fat percentage could be excluded. This MR estimated effect for WHR equates to a 1.23-fold higher odds of GORD per 5-cm increase in waist circumference. Conclusions: These results provide strong evidence that a higher waist-hip ratio leads to GORD. Our study suggests that central fat distribution is crucial in causing GORD rather than overall weight.This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site.S.E.J. is funded by the Medical Research Council (grant: MR/M005070/1). A.R.W., T.M.F and H.Y. are supported by the European Research Council grants: SZ-245 50371-GLUCOSEGENES-FP7-IDEAS-ERC and 323195. H.Y. is also funded by the Diabetes UK RD Lawrence fellowship (grant: 17/0005594). R.N.B. is funded by the Wellcome Trust and Royal Society, grant 104150/Z/14/Z. J.T. is supported by an Academy of Medical Sciences (AMS) Springboard award, which is supported by the AMS, the Wellcome Trust, GCRF, the Government Department of Business, Energy and Industrial strategy, the British Heart Foundation and Diabetes UK (SBF004\1079). N.A.K. declares personal fees from Falk, Takeda and Pharmacosmos; other fees from Janssen; and non-financial support from Janssen, AbbVie and Celltrion outside the submitted work. J.R.G. received honoraria from Falk, AbbVie and Shield therapeutics, outside the submitted work for unrelated topics. T.A. reports grants from AbbVie, MSD, Napp Pharmaceuticals, Celltrion, Pfizer, Janssen and Celgene during this study; personal fees and non-financial support from Immunodiagnostik; personal fees and non-financial support from Napp Pharmaceuticals, AbbVie and MSD; personal fees from Celltrion and Pfizer; grants and personal fees from Takeda; and grants and non-financial support from Tillotts, outside the submitted work.published version, accepted version (12 month embargo), submitted versio

    Influence of family history on penetrance of hereditary cancers in a population setting

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    This is the final version. Available on open access from Elsevier via the DOI in this recordData sharing statement: All data used in this study can be accessed via application to UK Biobank and approval via the data access committee. The authors are not permitted to directly share this data. The code used to perform GRS is available at https://github.com/hdg204/Rdna-nexus. Variants classified as pathogenic and used in this study are defined in the methods and can be replicated, however a list is available on request.BACKGROUND: We sought to investigate how penetrance of familial cancer syndromes varies with family history using a population-based cohort. METHODS: We analysed 454,712 UK Biobank participants with exome sequence and clinical data (data collected between March 2006 and June 2021). We identified participants with a self-reported family history of breast or colorectal cancer and a pathogenic/likely pathogenic variant in the major genes responsible for hereditary breast cancer or Lynch syndrome. We calculated survival to cancer diagnosis (controlled for sex, death, recruitment centre, screening and prophylactic surgery). FINDINGS: Women with a pathogenic BRCA1 or BRCA2 variant had an increased risk of breast cancer that was higher in those with a first-degree family history (relative hazard 10.3 and 7.8, respectively) than those without (7.2 and 4.7). Penetrance to age 60 was also higher in those with a family history (44.7%, CI 32.2-59.3 and 24.1%, CI 17.5-32.6) versus those without (22.8%, CI 15.9-32.0 and 17.9%, CI 13.8-23.0). A similar pattern was seen in Lynch syndrome: individuals with a pathogenic MLH1, MSH2 or MSH6 variant had an increased risk of colorectal cancer that was significantly higher in those with a family history (relative hazard 35.6, 48.0 and 9.9) than those without (13.0, 15.4 and 7.2). Penetrance to age 60 was also higher for carriers of a pathogenic MLH1 or MSH2 variant in those with a family history (30.9%, CI 18.1-49.3 and 38.3%, CI 21.5-61.8) versus those without (20.5% CI 9.6-40.5 and 8.3% CI 2.1-30.4), but not for MSH6 (6.5% CI 2.7-15.1 with family history versus 8.3%, CI 5.1-13.2). Relative risk increases were also observed both within and across conditions. INTERPRETATION: Individuals with pathogenic cancer syndrome variants may be at a less elevated risk of cancer in the absence of a first-degree family history, so in the context of results return, family history should be considered when counselling patients on the risks and benefits of potential follow-up care. FUNDING: The current work is supported by the MRC (grant no MR/T00200X/1). The MRC had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.Medical Research Council (MRC

    Backbone rigidity and static presentation of guanidinium groups increases cellular uptake of arginine-rich cell-penetrating peptides

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    In addition to endocytosis-mediated cellular uptake, hydrophilic cell-penetrating peptides are able to traverse biological membranes in a non-endocytic mode termed transduction, resulting in immediate bioavailability. Here we analysed structural requirements for the non-endocytic uptake mode of arginine-rich cell-penetrating peptides, by a combination of live-cell microscopy, molecular dynamics simulations and analytical ultracentrifugation. We demonstrate that the transduction efficiency of arginine-rich peptides increases with higher peptide structural rigidity. Consequently, cyclic arginine-rich cell-penetrating peptides showed enhanced cellular uptake kinetics relative to their linear and more flexible counterpart. We propose that guanidinium groups are forced into maximally distant positions by cyclization. This orientation increases membrane contacts leading to enhanced cell penetration

    Characterization of n-Hexane sub-fraction of Bridelia micrantha (Berth) and its antimycobacterium activity

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    <p>Abstract</p> <p>Background</p> <p>Tuberculosis, caused by <it>Mycobacterium tuberculosis </it>(MTB), is the most notified disease in the world. Development of resistance to first line drugs by MTB is a public health concern. As a result, there is the search for new and novel sources of antimycobacterial drugs for example from medicinal plants. In this study we determined the <it>in vitro </it>antimycobacterial activity of <it>n</it>-Hexane sub-fraction from <it>Bridelia micrantha </it>(Berth) against MTB H<sub>37</sub>Ra and a clinical isolate resistant to all five first-line antituberculosis drugs.</p> <p>Methods</p> <p>The antimycobacterial activity of the <it>n</it>-Hexane sub-fraction of ethyl acetate fractions from acetone extracts of <it>B. micrantha </it>barks was evaluated using the resazurin microplate assay against two MTB isolates. Bioassay-guided fractionation of the ethyl acetate fraction was performed using 100% <it>n</it>-Hexane and Chloroform/Methanol (99:1) as solvents in order of increasing polarity by column chromatography and Resazurin microtiter plate assay for susceptibility tests.</p> <p>Results</p> <p>The <it>n</it>-Hexane fraction showed 20% inhibition of MTB H<sub>37</sub>Ra and almost 35% inhibition of an MTB isolate resistant to all first-line drugs at 10 μg/mL. GC/MS analysis of the fraction resulted in the identification of twenty-four constituents representing 60.5% of the fraction. Some of the 24 compounds detected included Benzene, 1.3-bis (3-phenoxyphenoxy (13.51%), 2-pinen-4-one (10.03%), N(b)-benzyl-14-(carboxymethyl) (6.35%) and the least detected compound was linalool (0.2%).</p> <p>Conclusions</p> <p>The results show that the <it>n-</it>Hexane fraction of <it>B. micrantha </it>has antimycobacterial activity.</p

    Trial baseline characteristics of a cluster randomised controlled trial of a school-located obesity prevention programme; the Healthy Lifestyles Programme (HeLP) trial

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    This is the final version of the article. Available from BioMed Central via the DOI in this record.Background We have developed a healthy lifestyles programme (HeLP) for primary school aged children (9–10 years), currently being evaluated in a definitive cluster randomised controlled trial. This paper descriptively presents the baseline characteristics of trial children (BMI, waist circumference, % body fat, diet and physical activity) by gender, cluster level socio-economic status, school size and time of recruitment into the trial. Methods Schools were recruited from across the South West of England and allocated 1:1 to either intervention (HeLP) or control (usual practice) stratified by the proportion of children eligible for free school meals (FSM, 1 Year 5 class). The primary outcome is change in body mass index standard deviation score (BMI sds) at 24 months post-randomisation. Secondary outcomes are BMI sds at 18 months, waist circumference and percentage body fat sds at 18 and 24 months, proportion of children classified as underweight, overweight and obese at 18 and 24 months, physical activity (for a sub-sample) and food intake at 18 months. Results At baseline 11.4% and 13.6% of children were categorised as overweight or obese respectively. A higher percentage of girls than boys (25.3% vs 24.8%) and children from schools in FSM category 2 (28.2% vs 23.2%) were overweight or obese. Children were consuming a mean (range) of 4.15 (0–13) energy dense snacks (EDS) and 3.23 (0–9) healthy snacks (HS) per day with children from schools in FSM category 2 consuming more EDS and negative food markers and less HS and positive food markers. Children spent an average 53.6 min per day (11.9 to 124.8) in MVPA and thirteen hours (779.3 min) per day (11 h to 15 h) doing less than ‘light’ intensity activity. Less than 5% of children achieved the Departments of Health’s recommendation of 60 min of MVPA every day. Conclusion We have excellent completeness of baseline data for all measures and have achieved compliance to accelerometry not seen before in other large scale studies. Our anthropometric baseline data is representative of local and national data for children this age and reflects the gender and socio-economic variations expected of children this age in relation to physical activity and weight status.The definitive trial of HeLP is funded by the UK National Institute for Health Research (NIHR) Public Health Research Programme (10/3010/01) and a full report will be published on the NIHR website. Intervention materials and delivery was funded by the Peninsula College of Medicine and Dentistry. PenCLAHRC provided methodological support during the transition from the exploratory trial to the definitive evaluation

    Genome sequencing of the extinct Eurasian wild aurochs, Bos primigenius, illuminates the phylogeography and evolution of cattle

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    Background Domestication of the now-extinct wild aurochs, Bos primigenius, gave rise to the two major domestic extant cattle taxa, B. taurus and B. indicus. While previous genetic studies have shed some light on the evolutionary relationships between European aurochs and modern cattle, important questions remain unanswered, including the phylogenetic status of aurochs, whether gene flow from aurochs into early domestic populations occurred, and which genomic regions were subject to selection processes during and after domestication. Here, we address these questions using whole-genome sequencing data generated from an approximately 6,750-year-old British aurochs bone and genome sequence data from 81 additional cattle plus genome-wide single nucleotide polymorphism data from a diverse panel of 1,225 modern animals. Results Phylogenomic analyses place the aurochs as a distinct outgroup to the domestic B. taurus lineage, supporting the predominant Near Eastern origin of European cattle. Conversely, traditional British and Irish breeds share more genetic variants with this aurochs specimen than other European populations, supporting localized gene flow from aurochs into the ancestors of modern British and Irish cattle, perhaps through purposeful restocking by early herders in Britain. Finally, the functions of genes showing evidence for positive selection in B. taurus are enriched for neurobiology, growth, metabolism and immunobiology, suggesting that these biological processes have been important in the domestication of cattle. Conclusions This work provides important new information regarding the origins and functional evolution of modern cattle, revealing that the interface between early European domestic populations and wild aurochs was significantly more complex than previously thought

    Detection of Maternal Alcohol Use Problems in the Pediatric Emergency Department

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    Maternal alcohol use problems may impact the health and well-being of children, but often remain unrecognized. Mothers of young children seldom seek outpatient care for themselves; thus, pediatric settings may present an opportunity for the detection of maternal alcohol use problems. This study examines the feasibility of screening for and prevalence of alcohol use problems in mothers of young children in the context of seeking pediatric emergency care. We also examined the relationship of maternal alcohol use problems with use of pediatric emergency care. Methods : A total of 361 English-speaking mothers of children aged 7 and younger completed screening measures during their child's emergency care visit. TWEAK was used to screen for alcohol use problems. The screening survey also included information on children's health status and health care use, demographics, and the Center for Epidemiological Studies Depression Scale. Results : Of the women approached, 90% agreed to complete the screening measure. On the basis of cutoff score of 2 or more, 7% of women had elevated TWEAK scores. Those women with a TWEAK score >2 reported greater use of the pediatric emergency department (PED) than women scoring below the cutoff. On the basis of multivariate analyses, significant predictors of recent PED use included the presence of child chronic illness, younger maternal age, and TWEAK score. Conclusions : Screening for alcohol use problems among mothers of young children using the TWEAK appears to be feasible in a busy PED setting. The PED setting is promising for identifying risk drinking among women who may be less likely to be otherwise detected and for whom alcohol use may be impacting child outcomes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66222/1/j.1530-0277.2006.00132.x.pd

    The earth as a radio source

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    The primary characteristics of radio emission from the earth's magnetosphere are summarized, the origins of these missions are considered and similarities to other astronomical radio sources discussed. The auroral kilometric radiation has features very similar to Io-related decametric radiation from Jupiter and from Saturn. The radiation at fp and 2 fp upstream of the bow shock appears to be generated by the same mechanism as type III solar radio bursts. The beaming of the auroral kilometric radiation into a cone shaped region over the polar cap has some similarity to the angular distribution of radiation from Io and to the beaming of radio emission from pulsars
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