999 resultados para heart contraction


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The 2013 survey addressed the following objectives: Primary objectives : a) Distribution of health behaviors related to NCDs, particularly tobacco use, alcohol drinking, and physical activity ; b) Distribution of the main modifiable risk factors of NCDs, particularly blood pressure, adiposity markers, diabetes and blood lipids ; c) Rates of awareness, treatment and control of hypertension, diabetes and dyslipidemia ; d) Comparison of findings in the survey 2013 with results in previous similar NCD surveys in 1989, 1994, 2004 ; e) Dietary patterns ; f) Knowledge, attitudes and practices related to NCDs and NCD risk factors. Secondary objectives : g) Assessment of indicators of quality of health (e.g. SF‐12) ; h) Assessment of psychological stress and relation with NCD ; i) Assessment of several indicators of frailty (e.g. handgrip strength test, chair strand test, functional limitations) ; j) Assessment of knowledge and level of agreement with current policies on tobacco control ; k) Use of public and private health care services, particularly for NCDs ; l) Exposure to advice on health behaviors given by health professionals at health care level ; m) Burden of chronic diseases not related to the main NCDs (e.g. musculoskeletal, mental health, etc) ; n) Screening of selected cancers ; o) Assessment of the kidney function ; p) Frequency of heart arrhythmias (one‐lead ECG) and heart murmurs (auscultation) ; q) Assessment of bone mineral density (ultrasound of calcaneus) ; r) Exposure of the population to mass media, particularly in relation to health programs, and use by the population of new communication technologies ; s) Assessment of a number of social variables and their association with the variables measured in the survey ; t) More generally, the survey provides broad information (medical, social, environment, etc) that can be useful for tailoring NCD prevention and control programs.

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This report provides information on selected summary results of the National Survey of Noncommunicable Diseases in Seychelles in 2013‐2014 (Seychelles Heart Study IV). The survey is also referred shortly as the "2013 Survey" in this report. Overall crude results were reported in a comprehensive report in November 2014. Further detailed analyses and recommendations on particular topics will be performed separately.

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The key information processing units within gene regulatory networks are enhancers. Enhancer activity is associated with the production of tissue-specific noncoding RNAs, yet the existence of such transcripts during cardiac development has not been established. Using an integrated genomic approach, we demonstrate that fetal cardiac enhancers generate long noncoding RNAs (lncRNAs) during cardiac differentiation and morphogenesis. Enhancer expression correlates with the emergence of active enhancer chromatin states, the initiation of RNA polymerase II at enhancer loci and expression of target genes. Orthologous human sequences are also transcribed in fetal human hearts and cardiac progenitor cells. Through a systematic bioinformatic analysis, we identified and characterized, for the first time, a catalog of lncRNAs that are expressed during embryonic stem cell differentiation into cardiomyocytes and associated with active cardiac enhancer sequences. RNA-sequencing demonstrates that many of these transcripts are polyadenylated, multi-exonic long noncoding RNAs. Moreover, knockdown of two enhancer-associated lncRNAs resulted in the specific downregulation of their predicted target genes. Interestingly, the reactivation of the fetal gene program, a hallmark of the stress response in the adult heart, is accompanied by increased expression of fetal cardiac enhancer transcripts. Altogether, these findings demonstrate that the activity of cardiac enhancers and expression of their target genes are associated with the production of enhancer-derived lncRNAs.

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The identification and characterization of long noncoding RNA in a variety of tissues represent major achievements that contribute to our understanding of the molecular mechanisms controlling gene expression. In particular, long noncoding RNA play crucial roles in the epigenetic regulation of the adaptive response to environmental cues via their capacity to target chromatin modifiers to specific locus. In addition, these transcripts have been implicated in controlling splicing, translation and degradation of messenger RNA. Long noncoding RNA have also been shown to act as decoy molecules for microRNA. In the heart, a few long noncoding RNA have been demonstrated to regulate cardiac commitment and differentiation during development. Furthermore, recent findings suggest their involvement as regulators of the pathophysiological response to injury in the adult heart. Their high cellular specificity makes them attractive target molecules for innovative therapies and ideal biomarkers.

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Different asymmetries between expansion and contraction (radial motions) have been reported in the literature. Often these patterns have been regarded as implying different channels for each type of radial direction (outward versus inwards) operating at a higher level of visual motion processing. In two experiments (detection and discrimination tasks) we report reaction time asymmetries between expansion and contraction. Power functions were fitted to the data. While an exponent of 0.5 accounted for the expansion data better, a value of unity yielded the best fit for the contraction data. Instead of interpreting these differences as corresponding to different higher order motion detectors, we regard these findings as reflecting the fact that expansion and contraction tap two distinct psychophysical input channels underlying the processing of fast and slow velocities respectively.

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There are conflicting data on the prevalence of coronary events and the quality of the management of modifiable cardiovascular risk factors (CVRF) inHIV-infected patients. Methods.We performed a retrospective descriptive study to determine the prevalence of coronary events and to evaluate the management of CVRF in a Mediterranean cohort of 3760 HIV-1-infected patients from April 1983 through June 2011. Results.We identified 81 patients with a history of a coronary event (prevalence 2.15%); 83% of them suffered an acute myocardial infarction. At the time of the coronary event, CVRF were highly prevalent (60.5% hypertension, 48% dyslipidemia, and 16% diabetes mellitus).OtherCVRF, such as smoking, hypertension, lack of exercise, and body mass index, were not routinely assessed. After the coronary event, a significant decrease in total cholesterol ( � = 0.025) and LDLcholesterol ( � = 0.004) was observed. However, the percentage of patients whomaintained LDL-cholesterol > 100mg/dL remained stable (from 46% to 41%, � = 0.103). Patients using protease inhibitors associated with a favorable lipid profile increased over time ( � = 0.028). Conclusions.The prevalence of coronary events in our cohort is low. CVRF prevalence is high and theirmanagement is far from optimal. More aggressive interventions should be implemented to diminish cardiovascular risk in HIV-infected patients.

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Grâce à l'amélioration de la chirurgie cardiaque, les enfants avec une malformation cardiaque congénitale atteignent actuellement en grande majorité l'âge adulte avec une bonne qualité de vie. Un suivi cardiaque régulier est toutefois recommandé. La période de l'adolescence coïncide souvent avec la survenue de complications à moyen et long termes et la nécessité d'une reprise chirurgicale ou par cathétérisme interventionnel, en particulier chez les patients avec cardiopathie complexe. Par conséquent, il est primordial de débuter le processus de transition assez tôt et de la poursuivre jusqu'à l'âge adulte. Nous avons élaboré un programme de transition formel, adapté aux patients avec cardiopathie congénitale. With the improvement of congenital heart surgery, most children with congenital heart disease will survive into adulthood with a good quality of life. Regular cardiac follow-up is recommended for all patients. The adolescent period coincides often with medium and long term consequences and complications and repeat surgery or catheter interventions might be needed. It is therefore of prime importance to begin the transition process early and to pursue it well into adulthood. We have elaborated a formal transition program adapted to youngsters with congenital heart disease.

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This article provides expert opinion on the use of cardiovascular magnetic resonance (CMR) in young patients with congenital heart disease (CHD) and in specific clinical situations. As peculiar challenges apply to imaging children, paediatric aspects are repeatedly discussed. The first section of the paper addresses settings and techniques, including the basic sequences used in paediatric CMR, safety, and sedation. In the second section, the indication, application, and clinical relevance of CMR in the most frequent CHD are discussed in detail. In the current era of multimodality imaging, the strengths of CMR are compared with other imaging modalities. At the end of each chapter, a brief summary with expert consensus key points is provided. The recommendations provided are strongly clinically oriented. The paper addresses not only imagers performing CMR, but also clinical cardiologists who want to know which information can be obtained by CMR and how to integrate it in clinical decision-making.

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Weight regain after caloric restriction results in accelerated fat storage in adipose tissue. This catch-up fat phenomenon is postulated to result partly from suppressed skeletal muscle thermogenesis, but the underlying mechanisms are elusive. We investigated whether the reduced rate of skeletal muscle contraction-relaxation cycle that occurs after caloric restriction persists during weight recovery and could contribute to catch-up fat. Using a rat model of semistarvation-refeeding, in which fat recovery is driven by suppressed thermogenesis, we show that contraction and relaxation of leg muscles are slower after both semistarvation and refeeding. These effects are associated with (i) higher expression of muscle deiodinase type 3 (DIO3), which inactivates tri-iodothyronine (T3), and lower expression of T3-activating enzyme, deiodinase type 2 (DIO2), (ii) slower net formation of T3 from its T4 precursor in muscles, and (iii) accumulation of slow fibers at the expense of fast fibers. These semistarvation-induced changes persisted during recovery and correlated with impaired expression of transcription factors involved in slow-twitch muscle development. We conclude that diminished muscle thermogenesis following caloric restriction results from reduced muscle T3 levels, alteration in muscle-specific transcription factors, and fast-to-slow fiber shift causing slower contractility. These energy-sparing effects persist during weight recovery and contribute to catch-up fat.

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BACKGROUND: For free-breathing cardiovascular magnetic resonance (CMR), the self-navigation technique recently emerged, which is expected to deliver high-quality data with a high success rate. The purpose of this study was to test the hypothesis that self-navigated 3D-CMR enables the reliable assessment of cardiovascular anatomy in patients with congenital heart disease (CHD) and to define factors that affect image quality. METHODS: CHD patients ≥2 years-old and referred for CMR for initial assessment or for a follow-up study were included to undergo a free-breathing self-navigated 3D CMR at 1.5T. Performance criteria were: correct description of cardiac segmental anatomy, overall image quality, coronary artery visibility, and reproducibility of great vessels diameter measurements. Factors associated with insufficient image quality were identified using multivariate logistic regression. RESULTS: Self-navigated CMR was performed in 105 patients (55% male, 23 ± 12y). Correct segmental description was achieved in 93% and 96% for observer 1 and 2, respectively. Diagnostic quality was obtained in 90% of examinations, and it increased to 94% if contrast-enhanced. Left anterior descending, circumflex, and right coronary arteries were visualized in 93%, 87% and 98%, respectively. Younger age, higher heart rate, lower ejection fraction, and lack of contrast medium were independently associated with reduced image quality. However, a similar rate of diagnostic image quality was obtained in children and adults. CONCLUSION: In patients with CHD, self-navigated free-breathing CMR provides high-resolution 3D visualization of the heart and great vessels with excellent robustness.

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Fructose is a major component of dietary sugar and its overconsumption exacerbates key pathological features of metabolic syndrome. The central fructose-metabolising enzyme is ketohexokinase (KHK), which exists in two isoforms: KHK-A and KHK-C, generated through mutually exclusive alternative splicing of KHK pre-mRNAs. KHK-C displays superior affinity for fructose compared with KHK-A and is produced primarily in the liver, thus restricting fructose metabolism almost exclusively to this organ. Here we show that myocardial hypoxia actuates fructose metabolism in human and mouse models of pathological cardiac hypertrophy through hypoxia-inducible factor 1α (HIF1α) activation of SF3B1 and SF3B1-mediated splice switching of KHK-A to KHK-C. Heart-specific depletion of SF3B1 or genetic ablation of Khk, but not Khk-A alone, in mice, suppresses pathological stress-induced fructose metabolism, growth and contractile dysfunction, thus defining signalling components and molecular underpinnings of a fructose metabolism regulatory system crucial for pathological growth.

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AIMS: Notch1 signalling in the heart is mainly activated via expression of Jagged1 on the surface of cardiomyocytes. Notch controls cardiomyocyte proliferation and differentiation in the developing heart and regulates cardiac remodelling in the stressed adult heart. Besides canonical Notch receptor activation in signal-receiving cells, Notch ligands can also activate Notch receptor-independent responses in signal-sending cells via release of their intracellular domain. We evaluated therefore the importance of Jagged1 (J1) intracellular domain (ICD)-mediated pathways in the postnatal heart. METHODS AND RESULTS: In cardiomyocytes, Jagged1 releases J1ICD, which then translocates into the nucleus and down-regulates Notch transcriptional activity. To study the importance of J1ICD in cardiac homeostasis, we generated transgenic mice expressing a tamoxifen-inducible form of J1ICD, specifically in cardiomyocytes. Using this model, we demonstrate that J1ICD-mediated Notch inhibition diminishes proliferation in the neonatal cardiomyocyte population and promotes maturation. In the neonatal heart, a response via Wnt and Akt pathway activation is elicited as an attempt to compensate for the deficit in cardiomyocyte number resulting from J1ICD activation. In the stressed adult heart, J1ICD activation results in a dramatic reduction of the number of Notch signalling cardiomyocytes, blunts the hypertrophic response, and reduces the number of apoptotic cardiomyocytes. Consistently, this occurs concomitantly with a significant down-regulation of the phosphorylation of the Akt effectors ribosomal S6 protein (S6) and eukaryotic initiation factor 4E binding protein1 (4EBP1) controlling protein synthesis. CONCLUSIONS: Altogether, these data demonstrate the importance of J1ICD in the modulation of physiological and pathological hypertrophy, and reveal the existence of a novel pathway regulating cardiac homeostasis.