542 research outputs found

    Consensus-based statements for the management of mitochondrial stroke-like episodes [version 1; peer review: 2 approved]

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    BACKGROUND: Focal-onset seizures and encephalopathy are prominent features of a stroke-like episode, which is a severe neurological manifestation associated with subtypes of mitochondrial disease. Despite more than 30 years of research, the acute treatment of stroke-like episodes remains controversial. METHODS: We used the modified Delphi process to harness the clinical expertise of a group of mitochondrial disease specialists from five European countries to produce consensus guidance for the acute management of stroke-like episodes and commonly associated complications. RESULTS: Consensus on a new definition of mitochondrial stroke-like episodes was achieved and enabled the group to develop diagnostic criteria based on clinical features, neuroimaging and/or electroencephalogram findings. Guidelines for the management of strokelike episodes were agreed with aggressive seizure management strongly recommended at the outset of stroke-like episodes. CONCLUSIONS: Our consensus statement defines stroke-like episodes in terms of an epileptic encephalopathy and we have used this to revise both diagnostic criteria and guidelines for management. A prospective, multi-centre, randomised controlled trial is required for evaluating the efficacy of any compound on modifying the trajectory of stroke-like episodes

    Scaling leaf respiration with nitrogen and phosphorus in tropical forests across two continents

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    Leaf dark respiration (Rdark) represents an important component controlling the carbon balance in tropical forests. Here, we test how nitrogen (N) and phosphorus (P) affect Rdark and its relationship with photosynthesis using three widely separated tropical forests which differ in soil fertility. Rdark was measured on 431 rainforest canopy trees, from 182 species, in French Guiana, Peru and Australia. The variation in Rdark was examined in relation to leaf N and P content, leaf structure and maximum photosynthetic rates at ambient and saturating atmospheric CO2 concentration. We found that the site with the lowest fertility (French Guiana) exhibited greater rates of Rdark per unit leaf N, P and photosynthesis. The data from Australia, for which there were no phylogenetic overlaps with the samples from the South American sites, yielded the most distinct relationships of Rdark with the measured leaf traits. Our data indicate that no single universal scaling relationship accounts for variation in Rdark across this large biogeographical space. Variability between sites in the absolute rates of Rdark and the Rdark : photosynthesis ratio were driven by variations in N- and P-use efficiency, which were related to both taxonomic and environmental variability

    Blood pressure reduction and clinical outcomes with angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers: protocol for a systematic review and meta-regression analysis

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    Background Angiotensin-converting enzyme inhibitors (ACEis) and angiotensin II receptor blockers (ARBs) efficaciously reduce systolic blood pressure (BP), a well-established risk factor for myocardial infarction (MI). Both inhibit the renin-angiotensin system, albeit through different mechanisms, and produce similar reductions in BP. However, in parallel meta-analyses of ACEi and ARB trials, ACEis reduce risk of MI whereas ARBs do not—a phenomenon described as the ‘ARB-MI paradox’. In addition, ACEis reduce all-cause mortality, whereas ARBs do not, which appears to be independent of BP lowering. The divergent cardiovascular effects of ACE inhibitors and ARBs, despite similar BP reductions, are counter-intuitive. This systematic review aims to ascertain the extent to which clinical outcomes in randomised trials of ACEi and ARBs are attributable to reductions in systolic BP. Methods A comprehensive search of bibliographic databases will be performed to identify all randomised studies of agents of the ACEi and ARB class. Placebo and active comparator-controlled studies that report clinical outcomes, with greater than 500 person-years of follow-up in each study arm, will be included. Two independent reviewers will screen study records against a priori-defined eligibility criteria and perform data extraction. The Cochrane Risk of Bias Tool will be applied to all included studies. Studies retracted subsequent to initial publication will be excluded. Primary outcomes of interest include MI and all-cause mortality; secondary outcomes include stroke, heart failure, revascularisation and cardiovascular mortality. Meta-regression will be performed, evaluating the relationship between attained reduction in systolic BP and relative risk of each outcome, stratified by drug class. Where a BP-dependent effect exists (two-tailed p value < 0.05), relative risks, standardised per 10 mmHg difference in BP, will be reported for each study outcome. Publication bias will be examined using Funnel plots, and calculation of Egger’s statistic. Discussion This systematic review will provide a detailed synthesis of evidence regarding the relationship between BP reduction and clinical outcomes with ACEi and ARBs. Greater understanding of the dependency of the effect of each class on BP reduction will advance insight into the nature of the ARB-MI paradox and guide the future usage of these agents. Systematic review registration PROSPERO CRD4201707298

    Mineralizable nitrogen and denitrification enzyme activity drive nitrate concentrations in well-drained stony subsoil under lucerne (Medicago sativa L.)

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    Nitrogen (N) inputs to agricultural systems contribute substantially to soil nitrate (NO₃¯) concentrations, which increase NO₃¯ leaching and contamination of groundwater. The influence of soil microbes in regulating NO₃¯ concentrations in the topsoil are well studied but it is often assumed that microbial regulation of NO₃¯ concentrations in the subsoil is negligible. The aim of this study was to test this assumption by determining the relationships between microbial properties and NO₃¯ concentrations in both the subsoil and the topsoil. We measured the size of the mineralizable N (Nm) pool, microbial properties (microbial biomass, bacterial richness), nitrifier gene abundance (amoA gene copy number), denitrifier gene abundance (nirK and nirS gene copy number), denitrifier enzyme activity and NO₃¯ concentrations in the topsoil and the subsoil in a well-drained stony soil under an established lucerne crop. We used structural equation modelling (SEM) to identify and compare the linkages of microbial properties with NO₃¯ concentrations at each depth. In the topsoil, we found higher Nm, gene abundance, denitrification enzyme activity, bacterial richness, and microbial biomass than those in the subsoil, but there were no relationships between these variables and NO₃¯ concentrations in the topsoil (the SEM model explained 0.06% of the variability in NO₃¯ concentrations). In contrast, in the subsoil, NO₃¯ concentrations were strongly correlated with bacterial amoA abundance and denitrification enzyme activity, with both variables associated significantly with Nm. We found that bacterial richness was also associated with Nm in the subsoil. Our findings highlight that microbial properties are associated with NO₃¯ concentrations in the subsoil (the SEM model explained 82% the variability in NO₃¯ concentrations) and this suggest that nitrification and denitrification may contribute to regulating NO₃¯ concentrations in the subsoil. Our findings also suggest that denitrification contributes to reducing NO₃¯ concentrations in the subsoil. We conclude that studies addressing drivers of NO₃¯ leaching need to consider the potential for microbially-mediated attenuation (or an increase) in NO₃¯ concentrations throughout the soil profile

    Challenges of caring for children with mental disorders: Experiences and views of caregivers attending the outpatient clinic at Muhimbili National Hospital, Dar es Salaam - Tanzania

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    It is estimated that world-wide up to 20 % of children suffer from debilitating mental illness. Mental disorders that pose a significant concern include learning disorders, hyperkinetic disorders (ADHD), depression, psychosis, pervasive development disorders, attachment disorders, anxiety disorders, conduct disorder, substance abuse and eating disorders. Living with such children can be very stressful for caregivers in the family. Therefore, determination of challenges of living with these children is important in the process of finding ways to help or support caregivers to provide proper care for their children. The purpose of this study was to explore the psychological and emotional, social, and economic challenges that parents or guardians experience when caring for mentally ill children and what they do to address or deal with them. A qualitative study design using in-depth interviews and focus group discussions was applied. The study was conducted at the psychiatric unit of Muhimbili National Hospital in Tanzania. Two focus groups discussions (FGDs) and 8 in-depth interviews were conducted with caregivers who attended the psychiatric clinic with their children. Data analysis was done using content analysis. The study revealed psychological and emotional, social, and economic challenges caregivers endure while living with mentally ill children. Psychological and emotional challenges included being stressed by caring tasks and having worries about the present and future life of their children. They had feelings of sadness, and inner pain or bitterness due to the disturbing behaviour of the children. They also experienced some communication problems with their children due to their inability to talk. Social challenges were inadequate social services for their children, stigma, burden of caring task, lack of public awareness of mental illness, lack of social support, and problems with social life. The economic challenges were poverty, child care interfering with various income generating activities in the family, and extra expenses associated with the child's illness. Caregivers of mentally ill children experience various psychological and emotional, social, and economic challenges. Professional assistance, public awareness of mental illnesses in children, social support by the government, private sector, and non-governmental organizations (NGOs) are important in addressing these challenges

    The Secret Life of the Anthrax Agent Bacillus anthracis: Bacteriophage-Mediated Ecological Adaptations

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    Ecological and genetic factors that govern the occurrence and persistence of anthrax reservoirs in the environment are obscure. A central tenet, based on limited and often conflicting studies, has long held that growing or vegetative forms of Bacillus anthracis survive poorly outside the mammalian host and must sporulate to survive in the environment. Here, we present evidence of a more dynamic lifecycle, whereby interactions with bacterial viruses, or bacteriophages, elicit phenotypic alterations in B. anthracis and the emergence of infected derivatives, or lysogens, with dramatically altered survival capabilities. Using both laboratory and environmental B. anthracis strains, we show that lysogeny can block or promote sporulation depending on the phage, induce exopolysaccharide expression and biofilm formation, and enable the long-term colonization of both an artificial soil environment and the intestinal tract of the invertebrate redworm, Eisenia fetida. All of the B. anthracis lysogens existed in a pseudolysogenic-like state in both the soil and worm gut, shedding phages that could in turn infect non-lysogenic B. anthracis recipients and confer survival phenotypes in those environments. Finally, the mechanism behind several phenotypic changes was found to require phage-encoded bacterial sigma factors and the expression of at least one host-encoded protein predicted to be involved in the colonization of invertebrate intestines. The results here demonstrate that during its environmental phase, bacteriophages provide B. anthracis with alternatives to sporulation that involve the activation of soil-survival and endosymbiotic capabilities

    Pathogenic variants in MT-ATP6: A UK-based Mitochondrial Disease Cohort Study

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    Distinct clinical syndromes have been associated with pathogenic MT-ATP6 variants. In this cohort study, we identified 125 individuals (60 families) including 88 clinically affected individuals and 37 asymptomatic carriers. Thirty-one individuals presented with Leigh syndrome and seven with Neuropathy Ataxia Retinitis Pigmentosa. The remaining 50 patients presented with variable non-syndromic features including ataxia, neuropathy and learning disability. We confirmed maternal inheritance in 39 families, and demonstrated tissue segregation patterns and phenotypic threshold are variant-dependent. Our findings suggest that MT-ATP6-related mitochondrial disease is best conceptualised as a spectrum disorder and should be routinely included in genetic ataxia and neuropathy gene panels. This article is protected by copyright. All rights reserved

    Measurement of the branching fraction and CP content for the decay B(0) -> D(*+)D(*-)

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    This is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2002 APS.We report a measurement of the branching fraction of the decay B0→D*+D*- and of the CP-odd component of its final state using the BABAR detector. With data corresponding to an integrated luminosity of 20.4  fb-1 collected at the Υ(4S) resonance during 1999–2000, we have reconstructed 38 candidate signal events in the mode B0→D*+D*- with an estimated background of 6.2±0.5 events. From these events, we determine the branching fraction to be B(B0→D*+D*-)=[8.3±1.6(stat)±1.2(syst)]×10-4. The measured CP-odd fraction of the final state is 0.22±0.18(stat)±0.03(syst).This work is supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the A.P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation

    Measurement of D-s(+) and D-s(*+) production in B meson decays and from continuum e(+)e(-) annihilation at √s=10.6 GeV

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    This is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2002 APSNew measurements of Ds+ and Ds*+ meson production rates from B decays and from qq̅ continuum events near the Υ(4S) resonance are presented. Using 20.8 fb-1 of data on the Υ(4S) resonance and 2.6 fb-1 off-resonance, we find the inclusive branching fractions B(B⃗Ds+X)=(10.93±0.19±0.58±2.73)% and B(B⃗Ds*+X)=(7.9±0.8±0.7±2.0)%, where the first error is statistical, the second is systematic, and the third is due to the Ds+→φπ+ branching fraction uncertainty. The production cross sections σ(e+e-→Ds+X)×B(Ds+→φπ+)=7.55±0.20±0.34pb and σ(e+e-→Ds*±X)×B(Ds+→φπ+)=5.8±0.7±0.5pb are measured at center-of-mass energies about 40 MeV below the Υ(4S) mass. The branching fractions ΣB(B⃗Ds(*)+D(*))=(5.07±0.14±0.30±1.27)% and ΣB(B⃗Ds*+D(*))=(4.1±0.2±0.4±1.0)% are determined from the Ds(*)+ momentum spectra. The mass difference m(Ds+)-m(D+)=98.4±0.1±0.3MeV/c2 is also measured.This work was supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the Swiss NSF, A. P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation
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