833 research outputs found

    Physical activity and change in quality of life during menopause -an 8-year follow-up study

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    <p>Abstract</p> <p>Background and objectives</p> <p>The aim of this study was to study the role of menopausal status and physical activity on quality of life.</p> <p>Methods</p> <p>A total of 1,165 Finnish women aged 45-64 years from a national representative population-based study were followed up for 8 years. Study participants completed the Health 2000 study questionnaire and follow-up questionnaire in 2008. Ordinal logistic regression analysis was used to measure the effect of menopausal status on global quality of life (QoL). Other variables included in the analyses were age, education, change of physical activity as assessed with metabolic equivalents, change of weight and hormone therapy (HRT) use.</p> <p>Results</p> <p>Peri- and postmenopausal women increased their physical activity (28% and 27%) during the eight-year follow up period slightly more often than premenopausal (18%) women (p = 0.070). Menopausal status was not significantly correlated with change of QoL. QoL of the most highly educated women was more likely to improve than among the less educated (e<sup>b </sup>= 1.28, 95%CI 1.08 to 1.51 p = 0.002). Women whose physical activity increased or remained stable had greater chances for improved QoL than women whose physical activity decreased (e<sup>b </sup>= 1.49, 95%CI 1.23 p < 0.001 to 1.80, e<sup>b </sup>= 1.46, 95%CI 1.24 to 1.73 p < 0.001 respectively). Women whose weight remained stable during follow-up also improved their QoL compared to women who gained weight (e<sup>b </sup>= 1.26, 95%CI 1.07 to 1.50 p > 0.01). Women who had never used HRT had 1.26 greater odds for improved QoL (95%CI 1.02 to 1.56 p = < 0.05).</p> <p>Conclusion</p> <p>Improvement of global QoL is correlated with stable or increased physical activity, stable weight and high education, but not with change in menopausal status.</p

    Environmental Controls of InSAR-Based Periglacial Ground Dynamics in a Sub-Arctic Landscape

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    Periglacial environments are characterized by highly dynamic landscapes. Freezing and thawing lead to ground movement, associated with cryoturbation and solifluction. These processes are sensitive to climate change and variably distributed depending on multiple environmental factors. In this study, we used multi-geometry Sentinel-1 Synthetic Aperture Radar Interferometry (InSAR) to investigate the spatial distribution of the mean annual ground velocity in a mountainous landscape in Northern Norway. Statistical modeling was employed to examine how periglacial ground velocity is related to environmental variables characterizing the diverse climatic, geomorphic, hydrological and biological conditions within a 148 km(2) study area. Two-dimensional (2D) InSAR results document mean annual ground velocity up to 15 mm/yr. Vertical and horizontal velocity components in the East-West plane show variable spatial distribution, which can be explained by the characteristics of cryoturbation and solifluction operating differently over flat and sloping terrain. Statistical modeling shows that slope angle and mean annual air temperature variables are the most important environmental factors explaining the distribution of the horizontal and vertical components, respectively. Vegetation and snow cover also have a local influence, interpreted as indicators of the ground material and moisture conditions. The results show contrasted model performance depending on the velocity component used as a response variable. In general, our study highlights the potential of integrating radar remote sensing and statistical modeling to investigate mountainous regions and better understand the relations between environmental factors, periglacial processes and ground dynamics.Peer reviewe

    Role of the potassium/lysine cationic center in catalysis and functional asymmetry in membrane-bound pyrophosphatases

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    /Lys center was identified as part of the mechanism underlying this effect. These findings suggest that the mPPase homodimer possesses an asymmetry of active site performance that may be an ancient prototype of the rotational binding-change mechanism of F-type ATPases

    Na+-translocating Membrane Pyrophosphatases Are Widespread in the Microbial World and Evolutionarily Precede H+-translocating Pyrophosphatases

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    Membrane pyrophosphatases (PPases), divided into K+-dependent and K+-independent subfamilies, were believed to pump H+ across cell membranes until a recent demonstration that some K+-dependent PPases function as Na+ pumps. Here, we have expressed seven evolutionarily important putative PPases in Escherichia coli and estimated their hydrolytic, Na+ transport, and H+ transport activities as well as their K+ and Na+ requirements in inner membrane vesicles. Four of these enzymes (from Anaerostipes caccae, Chlorobium limicola, Clostridium tetani, and Desulfuromonas acetoxidans) were identified as K+-dependent Na+ transporters. Phylogenetic analysis led to the identification of a monophyletic clade comprising characterized and predicted Na+-transporting PPases (Na+-PPases) within the K+-dependent subfamily. H+-transporting PPases (H+-PPases) are more heterogeneous and form at least three independent clades in both subfamilies. These results suggest that rather than being a curious rarity, Na+-PPases predominantly constitute the K+-dependent subfamily. Furthermore, Na+-PPases possibly preceded H+-PPases in evolution, and transition from Na+ to H+ transport may have occurred in several independent enzyme lineages. Site-directed mutagenesis studies facilitated the identification of a specific Glu residue that appears to be central in the transport mechanism. This residue is located in the cytoplasm-membrane interface of transmembrane helix 6 in Na+-PPases but shifted to within the membrane or helix 5 in H+-PPases. These results contribute to the prediction of the transport specificity and K+ dependence for a particular membrane PPase sequence based on its position in the phylogenetic tree, identity of residues in the K+ dependence signature, and position of the membrane-located Glu residue

    Ecosystem shift of a mountain lake under climate and human pressure : A move out from the safe operating space

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    A multiproxy approach including chironomid, diatom, pollen and geochemical analyses was applied on short gravitational cores retrieved from an alpine lake (Lacul Balea) in the Southern Carpathians (Romania) to unveil how this lake responded to natural and anthropogenic forcing over the past 500 years.On the basis of chironomid and diatom assemblage changes, and supported by sediment chemical data and historical information, we distinguished two main phases in lake evolution. Before 1926 the lake was dominated by chironomids belonging to Micropsectra insignilobus-type and benthic diatoms suggesting well-oxygenated oligotrophic environment with only small-scale disturbance. We considered this state as the lake's safe operational space. After 1926 significant changes occurred: Tanytarsus lugens-type and T. mendax-type chironomids took over dominance and collector filterers increased until 1970 pointing to an increase in available nutrients. The diatom community showed the most pronounced change between 1950 and 1992 when planktonic diatoms increased. The highest trophic level was reconstructed between 1970 and 1992, while the indicator species of increasing nutrient availability, Asterionella formosa spread from 1982 and decreased rapidly at 1992. Statistical analyses evidenced that the main driver of the diatom community change was atmospheric reactive nitrogen (Nr) fertilization that drastically moved the community towards planktonic diatom dominance from 1950. The transformation of the chironomid community was primarily driven by summer mean temperature increase that also changed the dominant feeding guild from collector gatherers to collector falterers. Our results overall suggest that the speed of ecosystem reorganisation showed an unprecedented increase over the last 100 years; biological systems in many cases underwent threshold type changes, while several system components displayed non-hysteretic change between alternating community composition. We conclude that Lake Balea is outside of its safe operating space today. The main trigger of changes since 1926 was climate change and human impact acting synergically. (C) 2020 The Authors. Published by Elsevier B.V.Peer reviewe

    A Systematic Review of the Usefulness of Glial Fibrillary Acidic Protein for Predicting Acute Intracranial Lesions following Head Trauma

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    Background: The extensive use of computed tomography (CT) after acute head injury is costly and carries potential iatrogenic risk. This systematic review examined the usefulness of blood-based glial fibrillary acidic protein (GFAP) for predicting acute trauma-related CT-positive intracranial lesions following head trauma. The main objective was to summarize the current evidence on blood-based GFAP as a potential screening test for acute CT-positive intracranial lesions following head trauma.Methods: We screened MEDLINE, EMBASE, Psychlnfo, CINAHL, Web of Science, the Cochrane Database, Scopus, Clinical Trials, OpenGrey, ResearchGate, and the reference lists of eligible publications for original contributions published between January 1980 and January 2017. Eligibility criteria included: (i) population: human head and brain injuries of all severities and ages; (ii) intervention: blood -based GFAP measurement <= 24 h post-injury; and (iii) outcome: acute traumatic lesion on non-contrast head CT <= 24 h post-injury. Three authors completed the publication screening, data extraction, and quality assessment of eligible articles.Results: The initial search identified 4,706 articles, with 51 eligible for subsequent full-text assessment. Twenty-seven articles were ultimately included. Twenty-four (89%) studies reported a positive association between GFAP level and acute trauma-related intracranial lesions on head CT. The area under the receiver operating characteristic curve for GFAP prediction of intracranial pathology ranged from 0.74 to 0.98 indicating good to excellent discrimination. GFAP seemed to discriminate mass lesions and diffuse injury, with mass lesions having significantly higher GFAP levels. There was considerable variability between the measured GFAP averages between studies and assays. No well-designed diagnostic studies with specific GFAP cutoff values predictive of acute traumatic intracranial lesions have been published.Conclusion: Intracranial CT-positive trauma lesions were associated with elevated GFAP levels in the majority of studies. Methodological heterogeneity in GFAP assessments and the lack of well-designed diagnostic studies with commercially validated GFAP platforms hinder the level of evidence, and variability in levels of GFAP with no clearly established cutoff for abnormality limit the clinical usefulness of the biomarker. However, blood based GFAP holds promise as a means of screening for acute traumatic CT-positive lesion following head trauma

    Isometric force production parameters during normal and experimental low back pain conditions

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    BACKGROUND: The control of force and its between-trial variability are often taken as critical determinants of motor performance. Subjects performed isometric trunk flexion and extension forces without and with experiment pain to examine if pain yields changes in the control of trunk forces. The objective of this study is to determine if experimental low back pain modifies trunk isometric force production. METHODS: Ten control subjects participated in this study. They were required to exert 50 and 75% of their isometric maximal trunk flexion and extension torque. In a learning phase preceding the non painful and painful trials, visual and verbal feedbacks were provided. Then, subjects were asked to perform 10 trials without any feedback. Time to peak torque, time to peak torque variability, peak torque variability as well as constant and absolute error in peak torque were calculated. Time to peak and peak dF/dt were computed to determine if the first peak of dF/dt could predict the peak torque achieved. RESULTS: Absolute and constant errors were higher in the presence of a painful electrical stimulation. Furthermore, peak torque variability for the higher level of force was increased with in the presence of experimental pain. The linear regressions between peak dF/dt, time to peak dF/dt and peak torque were similar for both conditions. Experimental low back pain yielded increased absolute and constant errors as well as a greater peak torque variability for the higher levels of force. The control strategy, however, remained the same between the non painful and painful condition. Cutaneous pain affects some isometric force production parameters but modifications of motor control strategies are not implemented spontaneously. CONCLUSIONS: It is hypothesized that adaptation of motor strategies to low back pain is implemented gradually over time. This would enable LBP patients to perform their daily tasks with presumably less pain and more accuracy

    Pulse pressure and age at menopause

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    BACKGROUND: The objective of this study was to study the association of early age at menopause with pulse pressure (PP), a marker of arterial stiffness, and PP change. METHODS: The effect of natural menopause was studied in 2484 women from the Atherosclerosis Risk in Communities (ARIC) Study who had not used hormone replacement therapy and who had not had a hysterectomy. The cross-sectional association of age with PP was evaluated in the entire cohort. The cross-sectional association of recalled age at menopause was evaluated in the 1688 women who were postmenopausal at baseline. PP change over 6 years was assessed in relation to menopausal age separately in women who were postmenopausal at baseline and in those whose menopause occurred during the 6-year interval. RESULTS: Chronological age was strongly and positively associated with PP in cross-sectional analyses, but not independently associated with PP change. While menopausal age was not associated cross-sectionally with PP, early age at menopause (age<45) was significantly and independently associated with a slightly larger increase in PP (8.4, 95% CI 7.0–9.8) than later menopause (6.5, 95% CI 5.8;7.2). However, among normotensive women the difference was not statistically significant (p = 0.07, 6.1 vs 4.7). CONCLUSIONS: Early age at menopause may be related to a greater increase in arterial stiffness, but the effect appears to be small and further evidence is needed
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