Autorregulación del aprendizaje: una revisión sistemática en revistas de la base SciELO / Self'Regulated Learning: A Systematic Review Based in Scielo Journals

El concepto de autorregulación del aprendizaje ha asumido una importancia creciente en la literatura, ya que la investigación ha sugerido que los alumnos participan activamente en su proceso de aprendizaje, monitorizando y regulando su proceso de estudio con el fin de alcanzar determinados objetivos. La información recogida en revistas indexadas en la base Scielo, en cuanto a la autorregulación, todavía no ha sido sistematizada convenientemente. Por ello, se ha realizado una revisión sistemática de la literatura, con base en datos SciELO.org, en el período comprendido entre el año 2001 y el año 2011, para analizar las evidencias recogidas en diferentes investigaciones sobre: a) la naturaleza del aprendizaje autorregulado, b) su evaluación, c) la promoción de habilidades para la autorregulación y su utilidad en el contexto educativo y d) la posibilidad de implicación de los profesores en la promoción de dicho aprendizaje.

The concept of self-regulation in learning has been assuming a rising importance in the literature once the research has suggested that students participate actively in their learning process, monitoring and regulating their study process to achieve self-set goals. Nevertheless, the information about self-regulation has not been yet systematized on the journals indexed in Scielo. Therefore, the current study performed a systematic review of the literature on Scielo.org, between the period 2001 and 2011 to analyze the existence evidence regarding: a) the nature of self-regulated learning, b) it's assessment, c) the promotion of self-regulated skills and their usefulness in the context of education, and d) the potential implication of teachers on the promotion of lifelong learning.

Functional characterization of phosphodiesterases 4 in the rat carotid body: effect of oxygen concentrations.

The non-specific cAMP phosphodiesterase (PDE) inhibitor isobutyl- methylxanthine (IBMX) has been used to manipulate cAMP levels in carotid body (CB) preparations but the characterization of different PDE isoforms in CB has never been performed. PDE4 is one of the PDE families that uses cAMP as a specific substrate and changes its activity and affinity for drug inhibitors according to the degree of its phosphorylation. We investigated the effects of hypoxia on cAMP accumulation induced by different PDE4 inhibitors in the CB based on the hypothesis that acute changes in O(2) could interfere with their affinity.Concentration-response curves for the effects of the PDE4 selective inhibitors, rolipram and Ro 20-1724 and IBMX on cAMP were obtained in CBs, removed from rats and incubated in normoxia (20%O(2)) or hypoxia (5%O(2)).No differences were found between cAMP concentrations in normoxic and hypoxic conditions in the absence of PDE inhibitors. In both conditions, the E(max) calculated for IBMX was similar to that of the specific PDE4 inhibitors. Hypoxia shifted the concentration response curves to the left with the following rank order of potency IBMX> RO 20-1724=rolipram and increased E(max) by about 25%.This pharmacological approach supports the hypothesis that there is PDE4 activity in CBs that is enhanced by acute hypoxia although the low potency of the PDE4 inhibitors to increase cAMP do not support an important role for PDE4 activation in the O(2)-sensing machinery at the CB.

Bicarbonate-regulated soluble adenylyl cyclase (sAC) mRNA expression and activity in peripheral chemoreceptors.

UNLABELLED: Peripheral arterial chemoreceptors in the carotid body (CB) are modulated by pH/CO(2). Soluble adenylyl cyclase (sAC) is directly stimulated by bicarbonate ions (HCO(3)). Because CO(2)/HCO(3) mediates depolarization in chemoreceptors, we hypothesized that sAC mRNA would be expressed in the CB, and its expression and function would be regulated by CO(2)/HCO(3).Sprague-Dawley rats at postnatal days 16-17 were used to compare sAC mRNA gene expression between CB and non-chemosensitive tissues: superior cervical (SCG), petrosal (PG) and nodose ganglia (NG) by quantitative real time-PCR. Rat sAC gene expression was standardized to the expression of GAPDH (housekeeping gene) and the data were analyzed with the Pfaffl method. Gene and protein expression, and sAC regulation in the testis was used as a positive control. To determine the regulation of sAC mRNA expression and activity, all tissues were exposed to increasing concentrations of bicarbonate (0, 24, 44 mM, titrated with CO(2) and maintained a constant pH of 7.40). RESULTS: sAC mRNA expression was between 2-11% of CB expression in the SCG, PG and NG. Furthermore, only in the CB did HCO(3) upregulate sAC gene expression and increase cAMP levels. CONCLUSION: sAC mRNA and protein expression is present in peripheral arterial chemoreceptors and non-chemoreceptors. In the CB, CO(2)/HCO(3) not only activated sAC but also regulated its expression, suggesting that sAC may be involved in the regulation of cAMP levels in response to hyper/hypocapnia.

[Anticardiolipin antibodies in patients with cerebral vascular accident]. / Anticorpos anticardiolipina em doentes com acidente vascular cerebral.

Through a prospective controlled study of 81 non-selected patients with acute cerebral ischemia, admitted to the hospital over the period of one year, anticardiolipin antibodies (IgG and IgM) were compared to a control group with the objective of evaluating their place as independent risk factors for stroke. Stroke patients' anticardiolipin antibodies (ACA) were again measured at 6 months and compared to the initial values. At the time of the acute ischemic event, the patients' mean ACA IgM was significantly higher than that of the controls and, at 6 months, the patients' mean ACA IgG and IgM were significantly lower than at the time of stroke. Furthermore, through logistic regression analysis and taking into account all other stroke risk factors present in the patient population, ACA IgM's association with stroke was statistically significant. We conclude that ACA may have a role in the pathogenesis of acute cerebral ischemia. Their cross-reactivity with anti-oxidised LDL antibodies may constitute a link between atherosclerosis and thrombosis.