Exercise, the diurnal cycle of cortisol and cognitive impairment in older adults.

Exercise has been shown to reduce the risk of developing Mild Cognitive Impairment and Alzheimer's disease as well as to improve cognition in healthy and cognitively impaired individuals. However, the mechanisms of these benefits are not well understood. The stress hypothesis suggests that the cognitive benefits attributed to exercise may partially be mediated by changes in the cortisol secretion pattern. Chronic stress may increase the risk of AD and exacerbate the cognitive deficits and brain pathology characteristic of the condition while physical activity has been shown to attenuate most of stress consequences and risk factors for AD. Initially, research on the effects of cortisol on cognition and physical activity focused on cortisol levels at one time point but the circadian pattern of cortisol secretion is complex and it is still unclear which aspects are most closely associated with cognitive function. Thus, the aim of this review was to analyze the exercise/stress/cognition hypothesis focusing on the effects of the diurnal cycle of cortisol on cognitive function and physical activity in older adults with and without cognitive impairment.

Tiras reactivas de glucosa. Definición de un criterio de distribución entre equiposde atención primaria del presupuestoasignado a una gerencia

Objetivo: Definir el criterio de distribución entre los equipos de atención primaria (EAP) del presupuesto asignado para tiras reactivas de glucosa en un área de atención primaria. Diseño: Estudio descriptivo transversal. Emplazamiento: Área 11 de Atención Primaria de Madrid. Participantes: Pacientes diabéticos registrados en el Programa de Automonitorización de la Glucosa Sanguínea (AMGS), en el año 2001.Mediciones principales: Se analizó la frecuencia de autoanálisis recomendado, el consumo y coste medio anual por paciente, en función del tipo de tratamiento (con o sin insulina) y el nivel de atención que realiza el seguimiento: atención primaria (AP), atención especializada (AE) o colaboradoras/desplazados (Col/Desp) Resultados: El total de diabéticos incluidos en AMGS es de 15.615. El 45,1 por ciento está en tratamiento con insulina (TCI) y el 54,9 por ciento sin insulina (TSI). Un 77,4 por ciento son seguidos por AP y un 20 por ciento por AE. La frecuencia media mensual de autoanálisis recomendado es muy superior en AE que en AP, tanto en los pacientes TCI (44 frente a 29) como en los TSI (23 frente a 14).El coste medio anual por paciente es de 15.192 ptas. El coste por paciente TCI es un 52,2 por ciento más elevado si está en seguimiento por AE que en AP. En los pacientes TSI este incremento es del 44,1 por ciento. Conclusiones: El consumo de tiras reactivas de glucosa en cada EAP está determinado por el número y el tipo de pacientes (según tratamiento y quién realice el seguimiento), por lo que el criterio de distribución entre EAP del presupuesto de tiras reactivas debe incorporar estas variables (AU)

Muscle/heart isoform of mitochondrial adenine nucleotide translocase (ANT1) is transiently expressed during perinatal development in rat liver.

A postnatal increase in the content of mitochondrial ANT in rat liver which is related to the maturation of mitochondrial function has previously been reported [Schönfeld et al., Biochim. Biophys Acta 1144 (1993) 353-358]. In order to define the contribution of the ANT isoforms to this postnatal increase we have studied the expression of ANT1 and ANT2 isoforms in the liver during this period. The results show that in contrast to adult liver, perinatal liver expressed the ANT1 isoform at the mRNA and protein level, and that during this period the expression of ANT1 increased to a similar extent as total ANT content. It is concluded that the postnatal increase in ANT is mainly due to the ANT1 isoform and therefore, a role for the ANT1 isoform in the postnatal maturation of mitochondrial respiration in rat liver is suggested.

CCAAT/enhancer-binding proteins alpha and beta in brown adipose tissue: evidence for a tissue-specific pattern of expression during development.

CCAAT/enhancer-binding protein (C/EBP) alpha mRNA and its protein products C/EBP alpha and 30 kDa C/EBP alpha are expressed in rat brown-adipose tissue. Results also demonstrate the expression of C/EBP beta mRNA and its protein products C/EBP beta and liver inhibitory protein (LIP) in the tissue. The abundance of C/EBP alpha and C/EBP beta proteins in adult brown fat is similar to that found in adult liver. However, the expression of C/EBP alpha and C/EBP beta is specifically regulated in brown fat during development. C/EBP alpha, 30 kDa C/EBP alpha, C/EBP beta and LIP content is several-fold higher in fetal brown fat than in the adult tissue, or liver at any stage of development. Peak values are attained in late fetal life, in concurrence with the onset of transcription of the uncoupling protein (UCP) gene, the molecular marker of terminal brown-adipocyte differentiation. When adult rats are exposed to a cold environment, which is a physiological stimulus of brown-adipose tissue hyperplasia and UCP gene expression, a specific rise in C/EBP beta expression with respect to C/EBP alpha, 30 kDa C/EBP alpha and LIP is observed. Present data suggest that the C/EBP family of transcription factors has an important role in the development and terminal differentiation of brown-adipose tissue.

CCAAT/enhancer binding proteins alpha and beta are transcriptional activators of the brown fat uncoupling protein gene promoter.

Primary brown adipocytes differentiated in culture were transiently transfected with plasmids containing different extensions of the 5'-flanking region of the rat uncoupling protein gene placed upstream of the bacterial chloramphenicol acetyltransferase reporter gene. Co-transfection of expression vectors for CCAAT/enhancer binding protein (C/EBP) alpha and C/EBP beta trans-activated the rat uncoupling protein gene promoter due to sequences in the 5' proximal region. DNAse I footprint analysis showed the presence of two C/EBP binding sites at positions -457/-440 and -335/-318, which interact with purified C/EBP beta as well as with C/EBP proteins present in brown fat or liver nuclear extracts. Two copies of each site placed upstream of the enhancerless SV40 promoter confer C/EBP alpha and C/EBP beta responsiveness to this heterologous promoter when co-transfected into HepG2 cells. It is concluded that the UCP gene is a target for C/EBP-dependent transcriptional regulation. This suggests that the C/EBP family of transcription factors is involved in the establishment of the characteristic phenotype of the brown adipocyte.