Publications by authors named "Martina Valencia"

The coronavirus-disease-2019 (COVID-19) pandemic has had a devastating physical and psychological impact on society, especially on students. In this study, we describe the levels of physical activity (Physical-Activity-Questionnaire-Short-Form (IPAQ-SF)), Burnout (School-Burnout-Inventory for students (SBI-U)) and engagement (Utrecht-Work-Engagement-Scale-9 items (UWES-9S)) in a cohort of Latin American higher education students during the COVID-19 pandemic in 2020. We also determined whether physical activity, Burnout, and engagement are related according to gender and area of study.

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During prenatal life, exposure to synthetic glucocorticoids (SGCs) can alter normal foetal development, resulting in disease later in life. Previously, we have shown alterations in the dendritic cytoarchitecture of Purkinje cells in adolescent rat progeny prenatally exposed to glucocorticoids. However, the molecular mechanisms underlying these alterations remain unclear.

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Preterm babies treated with synthetic glucocorticoids in utero exhibit behavioural alterations and disturbances in brain maturation during postnatal life. Accordingly, it has been shown in preclinical studies that SGC exposure at a clinical dose alters the presynaptic and postsynaptic structures and results in synaptic impairments. However, the precise mechanism by which SGC exposure impairs synaptic protein expression and its implications are not fully elucidated.

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Several studies have indicated that abnormal prenatal changes in the circulating glucocorticoids (GCs), induced by either maternal stress or exogenous GC administration, significantly alter the development of Purkinje cells (PCs). Among the suggested mechanisms that could mediate this GC-dependent PC susceptibility are changes in the expression of type-1 metabotropic glutamate receptors (mGluR1). In the current study, we analyzed whether a single course of prenatally administered betamethasone phosphate (BET) in pregnant rats increased the immunohistochemical expression of mGluR1 in PCs and decreased PC dendritic growth.

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Previous animal studies have indicated that excessive prenatal circulating glucocorticoid (GC) levels induced by the antenatal administration of synthetic GC (sGC) significantly alter neuronal development in the cerebellar and hippocampal neurons of the offspring. However, it is unknown whether antenatal sGC administration results in long-term neocortical pyramidal cell impairment. In the current study, we examined whether an equivalent therapeutic dose of antenatal betamethasone phosphate (BET) in pregnant rats alters the Golgi-stained basilar dendritic length and histochemical expression of dendritic microtubule-associated protein 2 (MAP2) of neocortical pyramidal cells in infant, adolescent, and young adult offspring.

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Using classic Golgi staining methods, we previously showed that the administration of synthetic glucocorticoid betamethasone in equivalent doses to those given in cases of human premature birth generates long-term alterations in Purkinje cell dendritic development in the cerebellar cortex. In the present study, we evaluated whether betamethasone alters the immunohistochemical expression of proteins that participate in cerebellar Purkinje cell dendritic development and maintenance, including microtubule-associated protein 2 (MAP2), brain-derived neurotrophic factor (BDNF) and the tyrosine kinase B receptor (TrkB), which are located predominantly in the cerebellar molecular layer where Purkinje cell dendritogenesis occurs. Consistent with our previous Golgi stain studies, we observed that animals prenatally exposed to a single course of betamethasone showed long-term alterations in the expression of MAP2, BDNF and TrkB.

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In the current study, we analyzed the impact of antenatal betamethasone on macroscopic cerebellar development, Purkinje cell morphology and the expression of the neuroprotective protein calbindin-D28k. Pregnant rats (Sprague-Dawley) were randomly divided into two experimental groups: control (CONT) and betamethasone-treated (BET). At gestational day 20 (G20), BET dams were subcutaneously injected with a solution of 0.

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Background: Prenatal stress (PS) in experimental animals causes long-lasting changes in Purkinje cell dendritic morphology. Furthermore, these structural changes are associated with an increase in anxiogenic behaviors in the elevated plus maze (EPM) and open-field (OF) test.

Objectives: As environmental enrichment (EE) has significant restorative effects on brain neurons and behavior, the aim of this study was to evaluate if postweaning EE mitigates the decrease in Purkinje cell dendritic expansion and exploratory behavior induced by PS in mice.

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Background: Preterm babies treated with synthetic glucocorticoids (sGC) in utero exhibit behavioral alterations and disturbances in brain maturation during infancy. However, the effects on dentate granule cell morphology and spatial memory in rats that were given clinically equivalent doses of antenatal betamethasone remain unclear.

Methods: Pregnant rats were randomly divided into the following two experimental groups: control (CON) and betamethasone-treated (BET) groups.

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