45,732 research outputs found

    Circadian variations in aortic stiffness, sympathetic vasoconstriction, and post-ischemic vasodilation in adults with and without type 2 diabetes.

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    The current literature reveals a lack of information on the circadian variations of some important cardiovascular risk factors related to the work of the heart or the capacity to provide blood and oxygen to various tissues. These factors include aortic stiffness, peripheral vasoconstrictor responsiveness, and post-ischemic vasodilation capacity. Furthermore, it is not clear whether the impact of an external stressor capable of activating the sympathetic nervous system could have greater repercussions on the cardiovascular system in the morning than in the evening. Given the higher incidence of acute cardiovascular events in the morning than in the evening, the studies undertaken in this thesis aim to investigate the circadian variations of these factors that are linked to cardiovascular risk, both at rest and during acute activation of the sympathetic nervous system. Type 2 diabetes (T2DM) is a condition that induces deleterious changes in cardiovascular function, impacting cardiovascular mortality and morbidity. Thus, the impact of diabetes will be evaluated. As a secondary purpose, considering the sex differences in the incidence and prognosis of cardiovascular disease, the effect of sex will be evaluated. Aortic stiffness proved not to be increased in the morning compared to the evening at specific times when the cardiovascular risk is significantly different, both at rest and during sympathetic activation. However, while healthy older women show similar aortic stiffness values compared to their male counterparts during acute stress, older women with T2DM reported greater aortic stiffness compared to men with T2DM. The post-ischemic forearm vasodilation is blunted in the morning compared to the evening in healthy elderly and such an attenuated vasodilation capacity impairs blood flow supply towards the ischemic area. The presence of T2DM does not affect vasodilation capacity and reactive hyperemia, but induces circadian variations in arterial pressure. The peripheral vasoconstriction triggered by a standardized sympathetic stressor is similar between morning and evening, regardless of the presence of T2DM and reduced baseline vascular conductance values in the morning. However, the peripheral vasoconstriction responsiveness is blunted in individuals with T2DM than in healthy ones as sympathetic activation induces vasodilation on the contralateral forearm in individuals with T2DM and vasoconstriction in healthy age-matched subjects. This finding highlights a neurovascular response to an external stressor altered by T2DM. Taken together, our findings suggest that the baseline state of constriction of the peripheral vascular tissue is greater in the morning than in the evening, but this fact is not due to greater sympathetic vasoconstriction responsiveness in the morning. Higher morning vasoconstriction at baseline however affects the capacity of a vascular tissue to dilate and, in turn, to supply blood to an ischemic tissue. Similar sympathetic vasoconstriction responsiveness between morning and evening is a likely factor explaining similar or lower values of central artery stiffness in the morning than in the evening, not only at rest but also during sympathetic excitation. Paradoxically, adults with T2DM report an increase in sympathetic-mediated dilatation capacity on the vascular tissue, which might be a defense mechanism that allows to reduce the central pressor response during sympathetic excitation

    „Ich war mutig“: Eine qualitative Studie zur Rekonstruktion kindlicher Perspektiven auf Erfahrungen im pferdegestützten Setting

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    Das vorliegende kumulative Dissertationsprojekt besteht aus fünf Fachbeiträgen und befasst sich mit pferdegestützten Interventionen aus der Perspektive von Kindern. Zunächst wird eine kritische Auseinandersetzung mit dem Forschungsfeld tiergestützter Interventionen vorgenommen, da hier häufig Erklärungsansätze herangezogen werden, die wissenschaftlich nicht abgesichert sind. Diese Ansätze sollen in der eigenen Arbeit nicht reproduziert werden. Für die Erhebung des Forschungsstandes werden Studien herangezogen, welche sich mit der psychischen, sozialen und emotionalen Wirkung pferdegestützter Interventionen bei Kindern befassen. Das bearbeitete Forschungsdesiderat ergab sich aus der Betrachtung bestehender Studien, da die Kinderperspektive in diesem Zusammenhang bisher kaum wissenschaftlich betrachtet wurde. Um zu verstehen, was für Kinder an pferdegestützten Interventionen relevant ist, wird ein Forschungsdesign verwendet, welches die Kinder in den Forschungsprozess einbezieht, sodass sie ihre eigenen Relevanzen explizieren können. Somit wird eine neue Perspektive auf bestehende Forschungsergebnisse eröffnet, welche ein tieferes Verständnis für die Wirkweisen pferdegestützter Interventionen bietet und die Möglichkeit zur Evaluation der praktischen Durchführung beinhaltet. Die Ergebnisse beruhen auf der Befragung von 23 Kindern die wöchentlich an einer pferdegestützten Intervention teilnahmen. Die meisten der Kinder lebten zum Zeitpunkt des Interviews in Einrichtungen der Kinder- und Jugendhilfe und nicht bei ihren Familien und standen somit unter erhöhter psychosozialer Belastung. Wie Kinder pferdegestützte Förderung wahrnehmen, wird mit Hilfe von offenen Leitfadeninterviews und der Grounded Theory herausgearbeitet. Als zusätzliche Ausdrucksmöglichkeit der Kinder wurden Bilder, die sie vom pferdegestützten Setting malten, als ergänzendes Material genutzt und mittels Segmentanalyse ausgewertet. Am Ende der Arbeit ist festzuhalten, dass in pferdegestützten Interventionen, mit dem Ziel der Förderung von mentaler Gesundheit, reitpädagogische Fachkräfte Situationen mit Pferden konstruieren, die das interpersonale Vertrauen und das Selbstvertrauen von Kindern stärken, indem gezielt die Bewältigung von Herausforderungen mit dem Pferd unterstützend angeleitet wird. Insbesondere die zentrale Rolle der reitpädagogischen Fachkraft sowie relevante Wirkfaktoren werden vertieft betrachtet

    Neuroprotective Properties of Peptides

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    The development of a treatment strategy for neurodegenerative disorders is a serious issue for the healthcare world and a crucial subject of discussion. In the past two decades, a lot of focus has been placed on identifying the pathophysiological processes involved in neuronal death linked to neurodegenerative disorders and developing a variety of treatment options for neuroprotection. Numerous research teams have studied the use of peptides as neuroprotective treatments for different types of neurodegenerative disorders for a long time. The review aims to provide details about the roles of erythropoietin (EPO), glucagon-like peptide-1 (GLP-1), granulocyte colony-stimulating factor (G-CSF), and oxytocin (OXT) in neurodegenerative disorders as well as what cellular and molecular mechanisms they trigger to elicit the neuroprotective action, with a focus on neurodegenerative disorders

    Corticosterone enhances formation of non-fear but not fear memory during infectious illness

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    IntroductionSurvivors of critical illness are at high risk of developing post-traumatic stress disorder (PTSD) but administration of glucocorticoids during the illness can lower that risk. The mechanism is not known but may involve glucocorticoid modulation of hippocampal- and amygdala-dependent memory formation. In this study, we sought to determine whether glucocorticoids given during an acute illness influence the formation and persistence of fear and non-fear memories from the time of the illness.MethodsWe performed cecal ligation and puncture in male and female mice to induce an acute infectious illness. During the illness, mice were introduced to a neutral object in their home cage and separately underwent contextual fear conditioning. We then tested the persistence of object and fear memories after recovery.ResultsGlucocorticoid treatment enhanced object discrimination but did not alter the expression of contextual fear memory. During context re-exposure, neural activity was elevated in the dentate gyrus irrespective of fear conditioning.ConclusionsOur results suggest that glucocorticoids given during illness enhance hippocampal-dependent non-fear memory processes. This indicates that PTSD outcomes in critically ill patients may be improved by enhancing non-fear memories from the time of their illness

    Neuroanatomical and gene expression features of the rabbit accessory olfactory system. Implications of pheromone communication in reproductive behaviour and animal physiology

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    Mainly driven by the vomeronasal system (VNS), pheromone communication is involved in many species-specific fundamental innate socio-sexual behaviors such as mating and fighting, which are essential for animal reproduction and survival. Rabbits are a unique model for studying chemocommunication due to the discovery of the rabbit mammary pheromone, but paradoxically there has been a lack of knowledge regarding its VNS pathway. In this work, we aim at filling this gap by approaching the system from an integrative point of view, providing extensive anatomical and genomic data of the rabbit VNS, as well as pheromone-mediated reproductive and behavioural studies. Our results build strong foundation for further translational studies which aim at implementing the use of pheromones to improve animal production and welfare

    he Determiners of Temporal Lobe Epilepsy Surgery Outcome in a Developing Country

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    Background: Epilepsy surgery has become a successful treatment option for patients with drug-resistant epilepsies. Objectives: This study aimed to assess temporal lobe epilepsy (TLE) surgery outcome and its association with epilepsy duration, the presence of pre-surgical generalized tonic-clonic seizure (GTCS), and brain MRI findings. Materials & Methods: This retrospective study was performed from 2016 to 2020 at Loghman-Hakim Hospital, Tehran, Iran. The patients’ demographic data, epilepsy type, duration, frequency, brain image findings, the selected surgical approaches, and histopathological findings were collected. The post-operative seizure outcome was expressed one year according to the proposed International League Against Epilepsy (ILAE) classification system. The independent sample t-test, chi-square, and one-way analysis of variance were applied to analyze the differences between variables in terms of quantitative and categorical data. Results: A total number of 69 TLE surgeries were enrolled in our study. No differences were found in the surgical outcome base on the ILAE classification system of patients with lesional vs non-lesional MRIs (P=0.834). In patients with mesial temporal sclerosis, no correlation was found between the surgical approaches including selective amygdalohippocampectomy, anterior temporal lobectomy, and post-operative seizure outcome (P=0.142). Seven patients (10.1%) developed post-operative functional seizures. Conclusion: In our study, the epilepsy duration and the presence of GTCSs before surgery had no effect on the surgery outcome. In patients with mesial temporal sclerosis, amygdalohippocampectomy, and anterior temporal lobectomy did not confer different surgical outcomes. TLE patients with normal MRI showed similar surgical outcomes as lesional patients. A significantly high proportion of our patients developed functional seizures, postoperatively

    The integration of yoga breathing techniques in cognitive behavioral therapy for post-traumatic stress disorder: A pragmatic randomized controlled trial

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    IntroductionIn trauma-focused Cognitive Behavioral Therapy (TF-CBT), stabilization techniques are used before confrontation ones to increase stress/affect tolerance and thus effectiveness of CBT. This study investigated the effects of pranayama, meditative yoga breathing and breath holding techniques, as a complimentary stabilization technique in patients with post-traumatic stress disorder (PTSD).MethodsSeventy-four PTSD-patients (84% female, 44.2 ± 13 years) were randomized to receive either pranayama at the beginning of each TF-CBT session or TF-CBT alone. The primary outcome was self-reported PTSD severity after 10 sessions of TF-CBT. Secondary outcomes included quality of life, social participation, anxiety, depression, distress tolerance, emotion regulation, body awareness, breath-holding duration, acute emotional reaction to stress, and adverse events (AEs). Intention-to-treat (ITT) and exploratory per-protocol (PP) analyses of covariance with 95% confidence intervals (CI) were performed.ResultsITT analyses revealed no significant differences on primary or secondary outcomes, except for breath-holding duration in favor of pranayama-assisted TF-CBT (20.81 s, 95%CI = 13.05|28.60). PP analyses of 31 patients without AEs during pranayama revealed significantly lower PTSD severity (−5.41, 95%CI = -10.17|-0.64) and higher mental quality of life (4.89, 95%CI = 1.38|8.41) than controls. In contrast, patients with AEs during pranayama breath holding reported significantly higher PTSD severity (12.39, 95%CI = 5.08|19.71) than controls. Concurrent somatoform disorders were found to be a significant moderator of change in PTSD severity (p = 0.029).ConclusionIn PTSD patients without concurrent somatoform disorders, the integration of pranayama into TF-CBT might reduce post-traumatic symptoms and increase mental quality of life more efficiently than TF-CBT alone. The results remain preliminary until they can be replicated by ITT analyses.Clinical trial registrationClinicalTrials.gov, identifier NCT03748121

    The introduction and current status of the multidimensional model of pain neurobiology

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    Conceptual models are useful because they guide our practical actions related to whatever is represented by the model; this includes research that reveals the limitations of these actions and the potential for their improvement. These statements apply to many aspects of daily life and especially to pain as a challenge for both clinical practice specifically and neurobiology generally. In the first half of the 20th century, our conceptual model of pain, to the extent that it existed at all, was based on evidence supporting the proposition that pain emerged from activity within a very spatially limited set of central nervous system (CNS) structures located within the cerebral cortex and it's oligosynaptic connections with the thalamus. This CNS activity was strongly associated with the activation of physiologically distinct and specialized somatovisceral afferent fibers. All, or nearly all, aspects of the pain experience were thought to arise from, and be modified by, changes in that localized CNS activity. There was no compelling and widely accepted reason to consider an alternative model. However, neurophysiological, neuroanatomical, behavioral, and clinical evidence emerging in the late mid-20th century prompted a reconsideration of the prevailing model of pain neurobiology. Based on this new evidence and the perceived limitations of the prevailing model, pain could then be reasonably conceived as a multidimensional experience arising from the conjoint activation of physiologically and anatomically distinct but interacting CNS structures each separately mediating sensory discriminative, affective, and cognitive aspects of pain. This brief historical review describes the intellectual climate at the time this multidimensional model was proposed, the dispositions for resisting or accepting it, and concludes with a comment on the current status of the model as a fusion of distributed activations that create a unified perception of pain
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