Chronic treatment with glucocorticoids increases the mass of adipose tissue and promotes metabolic syndrome. However little is known about the molecular effects of dexamethasone on adipose biology. Here, we demonstrated that dexamethasone induces progenitor cells to undergo adipogenesis. In the adipogenic pathway, at least two cell types are found: cells with the susceptibility to undergo staurosporine-induced adipose conversion and cells that require both staurosporine and dexamethasone to undergo adipogenesis. Dexamethasone increased and accelerated the expression of main adipogenic genes such as pparg2, cebpa and srebf1c. Also, dexamethasone altered the phosphorylation pattern of C/EBPβ, which is an important transcription factor during adipogenesis. Dexamethasone also had effect on mature adipocytes mature adipocytes causing the downregulation of some lipogenic genes, promoted a lipolysis state, and decreased the uptake of glucose. These paradoxical effects appear to explain the complexity of the action of glucocorticoids, which involves the hyperplasia of adipose cells and insulin resistance.

Adipose cells store lipids in the cytoplasm and signal systemically through secretion of adipokines and other molecules that regulate body energy metabolism. Differentiation of fat cells and its regulation has been the focus of extensive research since the early 1970s. In this review, we had attempted to examine the research bearing on the control of adipose cell differentiation, some of it dating back to the early days when Howard Green and his group described the preadipocyte cell lines 3T3-L1 and 3T3-F442A during 1974-1975. We also concentrated our attention on research published during the last few years, emphasizing data described on transcription factors that regulate adipose differentiation, outside of those that were reported earlier as part of the canonical adipogenic transcriptional cascade, which has been the subject of ample reviews by several groups of researchers. We focused on the studies carried out with the two preadipocyte cell culture models, the 3T3-L1 and 3T3-F442A cells that have provided essential data on adipose biology.

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Introduction: Parenting stress and parental adjustment could implicate key differences in the relational dynamics that parents establish with their children, particularly when families come from vulnerable social contexts. Method: Participants were 142 fathers and mothers from a risk neighborhood of Chile. The variables examined were parenting stress (parental distress, parent–child dysfunctional interaction and difficult child) and parental adjustment (depression, anxiety, and stress). Parents also completed a sociodemographic characterization survey. The statistical analyses were a correlation analysis and multiple linear regression analyses. Results: Overall, not all components of parenting stress were related to parental adjustment. Only parental distress was found as a significant predictor of poor parental adjustment (greater depression, anxiety, and stress), but not parent–child dysfunctional interaction and having a difficult child. Conclusions: The present study findings highlight the influence of stress on parenting as a relevant dimension of research for the improvement of the intervention deployed by the state regarding the protection of vulnerable Chilean children, providing multiple clinical and psychosocial applications for research and intervention purposes.

The objective was to analyze anthropometric and physical performance variables as a function of chronological age and biological maturity in young Chilean tennis players. The study was observational, cross-sectional, with descriptive and analytical characteristics. Eighty-seven tennis players were evaluated (58 men 15.1 ± 0.8 years and 29 women, 15.3 ± 0.8 years). The measured anthropometric variables were a sprint test of 20m; a modified agility test; a sit-and-reach test and shoulder flexibility; manual grip strength; horizontal jump in feet; a medicine ball throw; a countermovement vertical jump; an abalakov vertical jump and a 20-m shuttle-run test. The growth velocity acceleration peak (APHV), skeletal muscle mass and fat mass were calculated, R2 and standard error of estimate (SEE) were examined. The results show that chronological age explained the anthropometric variables between 1 and 23% in men and 1 and 29% in women; by biological age, variables were explained between 3 and 53% in men and 2 and 42% in women. Of the physical performance variables, chronological age described between 2 and 24% of them in men and 1 and 29% in women; the same were explained by biological age between 1 and 19% in men and 1 and 26% in women. We conclude that anthropometric variables showed a better relationship with biological age, except for volume of fat tissue, while physical performance variables showed low association with both biological and chronological age.

ResumenLa presente investigación tuvo por objetivo analizar las representaciones sociales de estudiantes chilenos respecto al significado que tiene para ellos la Educación Física, disciplina que estudian. Se utilizó un diseño no experimental, de corte transversal y carácter mixto; la muestra estuvo compuesta por 200 estudiantes de la carrera de Pedagogía en Educación Física de 12 universidades del país, seleccionados bajo un criterio no probabilístico intencionado. Los resultados muestran como palabras definidoras con mayor peso semántico: salud, deporte, motricidad y movimiento. Se concluye que las representaciones sociales de esta especialidad están vinculadas a la salud y bienestar, asociadas al movimiento y estudio de la motricidad humana, otorgando un valor pedagógico a través de elementos como la actividad física, la recreación y el deporte.

El taekwondo (TKD) es caracterizado como un deporte intermitente y de alta-intensidad donde predominan la ejecución de movimientos rápidos y explosivos, con desplazamientos continuos y cambios de dirección (COD). Objetivo. El propósito de este estudio fue examinar la asociación entre la prueba TSAT y la fuerza explosiva y la velocidad lineal en 5-M en competidores de TKD de nivel nacional de ambos sexos. Material y métodos. A través de un diseño correlacional 14 competidores de ambos sexos que compiten habitualmente en torneos de nivel regional y nacional, (edad 19 ± 3 años; talla 164 ± 10 cm; peso corporal 62 ± 10 kg; experiencia 7.2 ± 2.9 años) participaron en este estudio. Como indicadores de fuerza explosiva se evaluó squat jump (SJ) y countermovement jump (CMJ), además de la velocidad lineal en 5-m (5-M) y la prueba de agilidad específica en taekwondo (TSAT) Resultados. Entre los principales hallazgos de este estudio se documentó una relación directa (r = .70) entre 5-M y TSAT; una relación inversa (r = -.63) entre SJ; CMJ (r = -.53) y TSAT respectivamente. Conclusiones. Nuestros datos muestran que la prueba de TSAT se relaciona con la velocidad lineal en 5-m y la fuerza explosiva. Los entrenadores deberían considerar el entrenamiento de estas cualidades, utilizando ejercicios similares para desarrollar la agilidad en competidores de TKD. Abstract. Taekwondo (TKD) is characterized as an intermittent and high-intensity sport in which predominates the execution of fast and explosive movements, with continuous movements and changes of direction (COD). Objective. The purpose of this study was to examine the association between the TSAT test, explosive strength, and 5-M line speed in national level TKD competitors of both sexes. Material and method. Through a correlational design, 14 competitors of both sexes who regularly compete in regional and national tournaments (age 19 ± 3 years; size 164 ± 10 cm; body weight 62 ± 10 kg; experience 7.2 ± 2.9 years), participated in this study. As indicators of explosive strength, squat jump (SJ) and countermovement jump (CMJ) were evaluated, as well as the 5-m linear speed (5-M) and the taekwondo-specific agility test (TSAT). Results. Among the main findings of this study, a direct relationship (r = .70) between 5-M and TSAT and an inverse relationship (r = -.63) between SJ, CMJ (r = -.53), and TSAT were documented, respectively. Conclusions. Our data shows that the TSAT test is related to 5-m linear velocity and explosive force. Coaches should consider training these qualities, using similar exercises to develop agility in TKD competitors.

El presente estudio tiene como objetivo analizar y comparar las actitudes hacia la educación física de escolares chilenos y alemanes, centrándose en el grado de importancia que ellos le otorgan a la asignatura y en el grado de conformidad que tienen con las clases que están recibiendo, según país, género y curso. Fueron encuestados 2.748 escolares de las regiones de la Araucanía en Chile (50%), y del Sarre en Alemania (50%). Se utilizó el “Cuestionario de Actitudes de los Escolares hacia la Educación Física”, elaborado y validado por el Instituto de Ciencias del Deporte de la Universidad del Sarre de Alemania. Los resultados indican que la mayoría de los escolares presentan actitudes positivas hacia la educación física. Se encontraron diferencias significativas entre el alumnado de ambos países, en donde los escolares de Chile le otorgan un mayor grado de importancia a la educación física que los escolares de Alemania, mientras que los escolares alemanes manifiestan un mayor grado de conformidad hacia la educación física que los escolares chilenos. Se establece que los varones le otorgan mayor importancia a la educación física que las damas, mientras que en el grado de conformidad estas diferencias según sexo no se presentan. Por último, se confirma que a medida que va aumentando la edad estas apreciaciones favorables hacia la educación física disminuyen. Los resultados de esta investigación indican que existe una favorable disposición del alumnado hacia la educación física, la cual se debe aprovechar para lograr mejores aprendizajes.Abstract: The object of the present study was to analyze and compare attitudes towards physical education among Chilean and German schoolchildren, concentrating on the degree of importance that they attribute to the subject and their degree of conformance with the classes that they receive, by country, gender, and school grade. A survey was applied to 2,748 schoolchildren in the Araucanía Region of Chile (50%) and the federal state of Saarland in Germany (50%). The survey used the “Questionnaire on Schoolchildren's Attitudes to Physical Education”, drafted and validated by the Institute of Sport Sciences of the University of Saarland in Germany. Results indicate that the majority of schoolchildren present positive attitudes towards physical education. Significant differences were found between pupils from the two countries: schoolchildren in Chile attribute a greater degree of importance to physical education than those in Germany, while German schoolchildren express a greater degree of conformance with physical education than Chileans. It was found that boys attribute greater importance to physical education than girls, but that no gender differences exist regarding the degree of conformance. Finally, it was found that as children advance in age, favorable opinions on physical education diminish. The results of this work indicate that pupils have a favorable disposition towards physical education, which should be exploited to increase learning.