99 research outputs found

    Non-equilibrium dynamics and floral trait interactions shape extant angiosperm diversity.

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    Why are some traits and trait combinations exceptionally common across the tree of life, whereas others are vanishingly rare? The distribution of trait diversity across a clade at any time depends on the ancestral state of the clade, the rate at which new phenotypes evolve, the differences in speciation and extinction rates across lineages, and whether an equilibrium has been reached. Here we examine the role of transition rates, differential diversification (speciation minus extinction) and non-equilibrium dynamics on the evolutionary history of angiosperms, a clade well known for the abundance of some trait combinations and the rarity of others. Our analysis reveals that three character states (corolla present, bilateral symmetry, reduced stamen number) act synergistically as a key innovation, doubling diversification rates for lineages in which this combination occurs. However, this combination is currently less common than predicted at equilibrium because the individual characters evolve infrequently. Simulations suggest that angiosperms will remain far from the equilibrium frequencies of character states well into the future. Such non-equilibrium dynamics may be common when major innovations evolve rarely, allowing lineages with ancestral forms to persist, and even outnumber those with diversification-enhancing states, for tens of millions of years

    Outcome-related metabolomic patterns from 1H/31P NMR after mild hypothermia treatments of oxygen–glucose deprivation in a neonatal brain slice model of asphyxia

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    Human clinical trials using 72 hours of mild hypothermia (32°C–34°C) after neonatal asphyxia have found substantially improved neurologic outcomes. As temperature changes differently modulate numerous metabolite fluxes and concentrations, we hypothesized that 1H/31P nuclear magnetic resonance (NMR) spectroscopy of intracellular metabolites can distinguish different insults, treatments, and recovery stages. Three groups of superfused neonatal rat brain slices underwent 45 minutes oxygen–glucose deprivation (OGD) and then were: treated for 3 hours with mild hypothermia (32°C) that began with OGD, or similarly treated with hypothermia after a 15-minute delay, or not treated (normothermic control group, 37°C). Hypothermia was followed by 3 hours of normothermic recovery. Slices collected at different predetermined times were processed, respectively, for 14.1 Tesla NMR analysis, enzyme-linked immunosorbent assay (ELISA) cell-death quantification, and superoxide production. Forty-nine NMR-observable metabolites underwent a multivariate analysis. Separated clustering in scores plots was found for treatment and outcome groups. Final ATP (adenosine triphosphate) levels, severely decreased at normothermia, were restored equally by immediate and delayed hypothermia. Cell death was decreased by immediate hypothermia, but was equally substantially greater with normothermia and delayed hypothermia. Potentially important biomarkers in the 1H spectra included PCr-1H (phosphocreatine in the 1H spectrum), ATP-1H (adenosine triphosphate in the 1H spectrum), and ADP-1H (adenosine diphosphate in the 1H spectrum). The findings suggest a potential role for metabolomic monitoring during therapeutic hypothermia

    Effectiveness of the 23-valent pneumococcal polysaccharide vaccine against vaccine serotype pneumococcal pneumonia in adults: A case-control test-negative design study.

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    BACKGROUND: Vaccination with the 23-valent pneumococcal polysaccharide vaccine (PPV23) is available in the United Kingdom to adults aged 65 years or older and those in defined clinical risk groups. We evaluated the vaccine effectiveness (VE) of PPV23 against vaccine-type pneumococcal pneumonia in a cohort of adults hospitalised with community-acquired pneumonia (CAP). METHODS AND FINDINGS: Using a case-control test-negative design, a secondary analysis of data was conducted from a prospective cohort study of adults (aged ≥16 years) with CAP hospitalised at 2 university teaching hospitals in Nottingham, England, from September 2013 to August 2018. The exposure of interest was PPV23 vaccination at any time point prior to the index admission. A case was defined as PPV23 serotype-specific pneumococcal pneumonia and a control as non-PPV23 serotype pneumococcal pneumonia or nonpneumococcal pneumonia. Pneumococcal serotypes were identified from urine samples using a multiplex immunoassay or from positive blood cultures. Multivariable logistic regression was used to derive adjusted odds of case status between vaccinated and unvaccinated individuals; VE estimates were calculated as (1 - odds ratio) × 100%. Of 2,357 patients, there were 717 PPV23 cases (48% vaccinated) and 1,640 controls (54.5% vaccinated). The adjusted VE (aVE) estimate against PPV23 serotype disease was 24% (95% CI 5%-40%, p = 0.02). Estimates were similar in analyses restricted to vaccine-eligible patients (n = 1,768, aVE 23%, 95% CI 1%-40%) and patients aged ≥65 years (n = 1,407, aVE 20%, 95% CI -5% to 40%), but not in patients aged ≥75 years (n = 905, aVE 5%, 95% CI -37% to 35%). The aVE estimate in relation to PPV23/non-13-valent pneumococcal conjugate vaccine (PCV13) serotype pneumonia (n = 417 cases, 43.7% vaccinated) was 29% (95% CI 6%-46%). Key limitations of this study are that, due to high vaccination rates, there was a lack of power to reject the null hypothesis of no vaccine effect, and that the study was not large enough to allow robust subgroup analysis in the older age groups. CONCLUSIONS: In the setting of an established national childhood PCV13 vaccination programme, PPV23 vaccination of clinical at-risk patient groups and adults aged ≥65 years provided moderate long-term protection against hospitalisation with PPV23 serotype pneumonia. These findings suggest that PPV23 vaccination may continue to have an important role in adult pneumococcal vaccine policy, including the possibility of revaccination of older adults

    Pneumococcal serotype trends, surveillance and risk factors in UK adult pneumonia, 2013-18.

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    BACKGROUND: Changes over the last 5 years (2013-18) in the serotypes implicated in adult pneumococcal pneumonia and the patient groups associated with vaccine-type disease are largely unknown. METHODS: We conducted a population-based prospective cohort study of adults admitted to two large university hospitals with community-acquired pneumonia (CAP) between September 2013 and August 2018. Pneumococcal serotypes were identified using a novel 24-valent urinary monoclonal antibody assay and from blood cultures. Trends in incidence rates were compared against national invasive pneumococcal disease (IPD) data. Persons at risk of vaccine-type pneumonia (pneumococcal conjugate vaccine (PCV)13 and pneumococcal polysaccharide vaccine (PPV)23) were determined from multivariate analyses. FINDINGS: Of 2934 adults hospitalised with CAP, 1075 (36.6%) had pneumococcal pneumonia. The annual incidence of pneumococcal pneumonia increased from 32.2 to 48.2 per 100 000 population (2013-18), predominantly due to increases in PCV13non7-serotype and non-vaccine type (NVT)-serotype pneumonia (annual incidence rate ratio 1.12, 95% CI 1.04 to 1.21 and 1.19, 95% CI 1.10 to 1.28, respectively). Incidence trends were broadly similar to IPD data. PCV13non7 (56.9% serotype 3) and PPV23non13 (44.1% serotype 8) serotypes were identified in 349 (32.5%) and 431 (40.1%) patients with pneumococcal pneumonia, respectively. PCV13-serotype pneumonia (dominated by serotype 3) was more likely in patients in the UK pneumococcal vaccination clinical risk group (adjusted OR (aOR) 1.73, 95% CI 1.31 to 2.28) while PPV23-serotype pneumonia was more likely in patients outside the clinical risk group (aOR 1.54, 95% CI 1.13 to 2.10). INTERPRETATION: The incidence of pneumococcal CAP is increasing, predominantly due to NVT serotypes and serotype 3. PPV23-serotype pneumonia is more likely in adults outside currently identified clinical risk groups

    Large-scale chromatin structure of inducible genes: transcription on a condensed, linear template

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    The structure of interphase chromosomes, and in particular the changes in large-scale chromatin structure accompanying transcriptional activation, remain poorly characterized. Here we use light microscopy and in vivo immunogold labeling to directly visualize the interphase chromosome conformation of 1–2 Mbp chromatin domains formed by multi-copy BAC transgenes containing 130–220 kb of genomic DNA surrounding the DHFR, Hsp70, or MT gene loci. We demonstrate near-endogenous transcription levels in the context of large-scale chromatin fibers compacted nonuniformly well above the 30-nm chromatin fiber. An approximately 1.5–3-fold extension of these large-scale chromatin fibers accompanies transcriptional induction and active genes remain mobile. Heat shock–induced Hsp70 transgenes associate with the exterior of nuclear speckles, with Hsp70 transcripts accumulating within the speckle. Live-cell imaging reveals distinct dynamic events, with Hsp70 transgenes associating with adjacent speckles, nucleating new speckles, or moving to preexisting speckles. Our results call for reexamination of classical models of interphase chromosome organization

    Dental Caries Risk Studies Revisited: Causal Approaches Needed for Future Inquiries

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    Prediction of high-risk individuals and the multi-risk approach are common inquiries in caries risk epidemiology. These studies prepared the ground for future studies; specific hypotheses about causal patterns can now be formulated and tested applying advanced statistical methods designed for causal studies, such as structural equation modeling, path analysis and multilevel modeling. Causal studies should employ measurements, analyses and interpretation of findings, which are in accordance to causal aims. Examples of causal empirical studies from medical and oral research are presented

    Metabolomics of Oxidative Stress in Recent Studies of Endogenous and Exogenously Administered Intermediate Metabolites

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    Aerobic metabolism occurs in a background of oxygen radicals and reactive oxygen species (ROS) that originate from the incomplete reduction of molecular oxygen in electron transfer reactions. The essential role of aerobic metabolism, the generation and consumption of ATP and other high energy phosphates, sustains a balance of approximately 3000 essential human metabolites that serve not only as nutrients, but also as antioxidants, neurotransmitters, osmolytes, and participants in ligand-based and other cellular signaling. In hypoxia, ischemia, and oxidative stress, where pathological circumstances cause oxygen radicals to form at a rate greater than is possible for their consumption, changes in the composition of metabolite ensembles, or metabolomes, can be associated with physiological changes. Metabolomics and metabonomics are a scientific disciplines that focuse on quantifying dynamic metabolome responses, using multivariate analytical approaches derived from methods within genomics, a discipline that consolidated innovative analysis techniques for situations where the number of biomarkers (metabolites in our case) greatly exceeds the number of subjects. This review focuses on the behavior of cytosolic, mitochondrial, and redox metabolites in ameliorating or exacerbating oxidative stress. After reviewing work regarding a small number of metabolites—pyruvate, ethyl pyruvate, and fructose-1,6-bisphosphate—whose exogenous administration was found to ameliorate oxidative stress, a subsequent section reviews basic multivariate statistical methods common in metabolomics research, and their application in human and preclinical studies emphasizing oxidative stress. Particular attention is paid to new NMR spectroscopy methods in metabolomics and metabonomics. Because complex relationships connect oxidative stress to so many physiological processes, studies from different disciplines were reviewed. All, however, shared the common goal of ultimately developing “omics”-based, diagnostic tests to help influence therapies
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