286 research outputs found

    Left atrial deformation analysis by speckle tracking echocardiography to predict exercise capacity after myocardial infarction

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    Introduction: Left atrial (LA) size and function are associated with outcome after myocardial infarction (MI). In this study we aimed to assess the impact of LA function as a predictor of exercise capacity through speckle tracking echocardiography. Methods: A total of 94 patients (mean age 54.8 +/- 11.0 years; 82% male) were enrolled one month after MI. Echocardiography was used to assess LA volumes and various indices of LA conduit, contraction and reservoir function. LA deformation was assessed by two-dimensional speckle tracking to calculate strain and strain rate at different phases of the cardiac cycle. Exercise capacity was assessed by oxygen uptake (VO2) on cardiopulmonary exercise testing. Results: Increased LA volumes, especially LA volume before atrial contraction, were correlated with reduced peak VO2 and reduced VO2 at anaerobic threshold. Decreased peak VO2 was associated with reduced LA conduit function (p=0.24; p=0.02), but not with LA booster function (p=-0.07; p=0.53). Lower peak atrial longitudinal strain was associated with worse exercise capacity (p=0.24; p=0.02). Conclusions: After MI, increased LA volumes were markers of decreased functional capacity that was associated with decreased LA conduit function, but not with LA contractile function. In these patients, LA longitudinal strain analysis may be useful to predict reduced exercise capacity. (C) 2018 Sociedade Portuguesa de Cardiologia. Published by Elsevier Espana, S.L.U.This work was supported by the Portuguese Foundation for Science and Technology grants PEst-C/SAU/UI0051/2011 and EXCL/BIM-MEC/0055/2012 through the Cardiovascular R&D Unit and by European Commission grant FP7-Health-2010; MEDIA-261409

    Optimal control for an irrigation planning problem: characterisation of solution and validation of the numerical results

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    In a previous study, the authors developed the planning of the water used in the irrigation systems of a given farmland in order to ensure that the field cultivation is in a good state of preservation. This planning was modelled and tackled as an optimal control problem: minimize the water flow (control) so that the extent water amount in the soil (trajectory) fulfils the cultivation water requirements. In this paper, we characterize the solution of our problem guaranteeing the existence of the solution and applying the necessary and sufficient conditions of optimality. We validate the numerical results obtained previously, comparing the analytical and numerical solutions.PEst-OE/MAT/UI0013/2014 and PEST-C/FIS/UI607/2013, European Union FP7 (FP7-PEOPLE-2010-ITN, Grant Agreement no. 264735- SADCO), FCT projects PTDC/EEA-CRO/116014/2009 and PTDC/EEI-AUT/1450/201

    The Psychedelic State Induced by Ayahuasca Modulates the Activity and Connectivity of the Default Mode Network

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    The experiences induced by psychedelics share a wide variety of subjective features, related to the complex changes in perception and cognition induced by this class of drugs. A remarkable increase in introspection is at the core of these altered states of consciousness. Self-oriented mental activity has been consistently linked to the Default Mode Network (DMN), a set of brain regions more active during rest than during the execution of a goal-directed task. Here we used fMRI technique to inspect the DMN during the psychedelic state induced by Ayahuasca in ten experienced subjects. Ayahuasca is a potion traditionally used by Amazonian Amerindians composed by a mixture of compounds that increase monoaminergic transmission. In particular, we examined whether Ayahuasca changes the activity and connectivity of the DMN and the connection between the DMN and the task-positive network (TPN). Ayahuasca caused a significant decrease in activity through most parts of the DMN, including its most consistent hubs: the Posterior Cingulate Cortex (PCC)/Precuneus and the medial Prefrontal Cortex (mPFC). Functional connectivity within the PCC/Precuneus decreased after Ayahuasca intake. No significant change was observed in the DMN-TPN orthogonality. Altogether, our results support the notion that the altered state of consciousness induced by Ayahuasca, like those induced by psilocybin (another serotonergic psychedelic), meditation and sleep, is linked to the modulation of the activity and the connectivity of the DMN.The Brazilian Federal Agencies: CNPq, CAPES; FINEP; The Sao Paulo State financial agency (FAPESP)

    Stimulation of endothelial progenitor cells: a new putative effect of several cardiovascular drugs

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    The role of vascular endothelium in cardiovascular disorders is well recognized. Mature endothelial cells contribute to the repair of endothelial injury, but they only have a limited capacity to do so. This has led to growing interest and further investigation into circulating endothelial progenitor cells (EPCs) and their role in vascular healing, repair, and postnatal neovascularization. The current perception of vascular health is that of a balance between ongoing injury and resultant vascular repair, mediated at least in part by circulating EPCs. Circulating EPCs play an important role in accelerating endothelialization at areas of vascular damage, and EPC enumeration is a viable strategy for assessing reparative capacity. Recent studies have shown that EPCs are affected both in number and function by several cardiovascular risk factors as well as various cardiovascular disease states, such as hypertension, hypercholesterolemia, and coronary artery disease. The present review summarizes the most relevant studies on the effects of cardiovascular drugs on vascular function and EPCs, focusing on their mechanisms of action

    Coriolus versicolor biomass increases dendritic arborization of newly-generated neurons in mouse hippocampal dentate gyrus

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    Brain cognitive reserve refers to the ability of the brain to manage different challenges that arise throughout life, making it resilient to neuropathology. Hippocampal adult neurogenesis has been considered to be a relevant contributor for brain cognitive reserve and brain plasticity. Coriolus versicolor (CV), a common healthful mushroom, has been receiving increasing attention by its antitumoral, anti-inflammatory, antioxidant, antibacterial, and immunomodulatory properties, including in the hippocampus. Herein, we evaluated whether CV biomass oral administration for 2.5 months enhances hippocampal neurogenic reserve under normal/physiological conditions, by quantifying hippocampal dentate gyrus (DG) granular cell layer (GCL) and subgranular zone (SGZ) volumes, proliferation, number and dendritic complexity features of hippocampal newly-generated neurons. We also analyzed β-catenin levels in DG newly-generated immature neurons, because it plays a major role in neurogenesis. Although no differences were observed in the volume of GCL and SGZ layers, in proliferation and in the number of newly-generated neurons of controls and CV-administered mice, we found that CV administration promotes a significant increase in dendritic length and branching and total dendritic volume of immature neurons, suggesting a positive effect of oral CV administration in the hippocampal neurogenic reserve. We also observed that β-catenin levels are increased both in the nucleus and cytoplasm of DG immature neurons, suggesting that Wnt/β-catenin signalling may play an important role in the CV positive effect on the differentiation of these cells. These data unveil a so far unexplored neurogenic potential of CV supplementation, which emerges as a possible preventive strategy for different neurological conditions.This work was supported by Mycology Research Laboratories, Ltd. This work was financed by the European Regional Development Fund (ERDF), through the Centro 2020 Regional Operational Programme under projects CENTRO-01-0145-FEDER-000012-HealthyAging2020 and CENTRO-01-0145-FEDER-000008 - BrainHealth 2020, and through the COMPETE 2020 - Operational Programme for Competitiveness and Internationalisation and Portuguese national funds via FCT – Fundação para a Ciência e a Tecnologia, under project POCI-01-0145-FEDER-007440 and Strategic Project 2015- UID/NEU/04539/2013. EF and SIM are holders of FCT postdoctoral grant (SFRH/BPD/86551/2012 and SFRH/BPD/99219/2013, respectively). J.V. salary was supported by an Ikerbasque Research Fellow grant

    Xylo-oligosaccharides display a prebiotic activity when used to supplement wheat or corn-based diets for broilers

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    It is now well established that exogenous β-1,4-xylanases improve the nutritive value of wheat-based diets for poultry. Among other factors, the mechanism of action of exogenous enzymes may involve a microbial route resulting from the generation of prebiotic xylo-oligosaccharides (XOS) in the birds' gastro-intestinal (GI) tract. In a series of three experiments, the effect of XOS on the performance of broilers fed wheat or corn-based diets was investigated. In experiment 1, birds receiving diets supplemented with XOS displayed an increased weight gain (P = 0.08). The capacity of XOS to improve the performance of animals during a longer trial (42 d) was investigated (Experiment 2). The data revealed that diet supplementation with XOS, tested at two incorporation rates (0.1 and 1 g/kg), or with an exogenous β-1,4-xylanase resulted in an increased nutritive value of the wheat-based diet. An improvement in animal performance was accompanied by a shift in the microbial populations colonizing the upper portions of the GI tract. XOS were also able to improve the performance of broilers fed a corn-based diet, although the effects were not apparent at incorporation rates of 10 g/kg. Together these studies suggest that in some cases the capacity of β-1,4-xylanases to improve the nutritive value of wheat-based diets is more related to their ability to produce prebiotic XOS than to their ability to degrade arabinoxylans. The extremely low quantities of XOS used in this study also challenge the depiction of a prebiotic being a quantitatively fermented substrate. These data also bring into question the validity of the "cell wall" mechanism, as XOS elicited an effect with clearly no action on endosperm cell wall integrity and yet the performance effects noted were equivalent or superior to the added enzymes.publishe
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