Objective: To evaluate body composition differences between children that were born small (SGA) or large for gestational age (LGA) compared with their counterparts born adequate for gestational age (AGA). Methods: Body composition was assessed in 124 healthy Caucasian children (50% girls) aged 6-10, classified according to their birth weight for gestational age as AGA, SGA and LGA. Fat mass (FM), percentage of FM, lean mass (LM), bone mineral content (BMC) and bone mineral density were measured by dual-energy X-ray absorptiometry (DXA) in the whole body and at different body regions. Results: LM (adjusted for age and sex) and total BMC (adjusted for age, sex and weight) were both significantly higher in LGA children and lower in SGA when compared with those born AGA. After adjustments for height, LM and BMC differences between groups were not significant. In SGA children, truncal (P < 0.05) and abdominal fatness (P < 0.01) were higher when compared with both AGA and LGA children, after adjustments for age, sex and height. There were no differences in the percentage of total and central FM between children born LGA and AGA. Conclusions: During childhood, children born SGA had higher central adiposity regardless of their body size. Children born LGA seem to have a higher body size but with harmonic body composition and adequate body fat distribution. Small size for gestational age at birth could programme excess abdominal fat deposition in children, which is a major factor for the clustering of cardiovascular disease risk factors defining the metabolic syndrome.

Objetivo: Evaluar las diferencias que existen en la composición corporal de aquellos niños que nacieron pequeños (PEG) o grandes para su edad gestacional (GEG) en comparación con los que presentaban un peso adecuado al nacer (AEG). Métodos: La composición corporal se valoró en 124 niños caucásicos (50% niñas) con edades entre 6 y 10 años, clasificados según su peso al nacer como AEG, PEG y GEG. La masa grasa (MG), el porcentaje de MG, la masa magra (MM), el contenido mineral óseo (CMO) y la densidad mineral ósea se midieron mediante absorciometría dual de rayos X (DXA) tanto globalmente como en las diferentes regiones corporales. Resultados: La MM (ajustada por edad y sexo) y el CMO (ajustado por edad, sexo y peso) fueron mayores en los GEG y menores en los PEG al compararlos con los AEG; al ajustar la MM el CMO por la altura, dichas diferencias ya no fueron significativas. En los PEG, la grasa abdominal (p < 0,01) y en el tronco (p < 0,05) eran mayores que en los AEG y que en los GEG tras ajustar por edad, sexo y altura. No existían diferencias en el porcentaje de MG total corporal y en porcentaje de grasa central entre los niños nacidos GEG y AEG. Conclusiones: Durante la infancia, los niños que nacieron PEG tenían mayor adiposidad central independientemente de su tamaño corporal. Los nacidos GEG seguían siendo grandes pero con una distribución armónica de la composición corporal y una adecuada distribución de la grasa corporal. Nacer con poco peso puede programar la grasa abdominal durante la infancia, cuyo aumento constituye uno de los factores de riesgo cardiovascular que definen el síndrome metabólico.

Objectives: To analyse the effect of zinc supplementation in growth and nutritional status of a homogeneous group of newborns with intra uterine growth retardation and asymmetric growth. The effect of changes of zinc status on growth and leptin serum concentrations was also analysed. Population and methods: A double blind, randomised clinical trial was designed in order to detect differences in growth between zinc and placebo groups during the first 6 months of life. 31 infants were included either to the zinc group (n = 14) (38.8 ± 1.4 weeks GA, 2,171 ± 253 g body weight) or the placebo group (n = 17) (38.9 ± 1.1 weeks GA, 2,249 ± 220 g body weight). The zinc group received a supplement of 3 mg elemental zinc per day (as zinc sulphate). Results: There were not significant differences between groups for anthropometric measurements through the study period. We found a significant effect of the study group, in hair zinc concentrations, but not in serum zinc concentrations; post-hoc comparisons for hair zinc revealed that there were significant differences between groups at 1, 2, and 6 months of age. Changes in serum and hair zinc concentrations from baseline to 6 months, showed significant correlations with changes in weight/age and length/age z-scores, in the supplement group. Changes in leptin serum concentrations during follow-up, showed significant correlations with changes in sum of 4 skinfolds and weight/age z-score, in the placebo group. Changes in hair zinc concentration through the study period showed significant correlations with changes in leptin serum concentrations from baseline to 6 months of follow-up. Conclusions: In a homogeneous group of intra uterine growth retardation infants with asymmetric growth, 3 mg/day zinc supplementation do not show significant improvements in weight and length growth. Changes in zinc status were related with changes in weight and length during the first 6 months of life. Changes in leptin serum concentrations were related with changes in the anthropometric indices of body fat accretion.

Objetivos: Valorar el efecto de la suplementación con cinc en el crecimiento y estado nutricional de un grupo homogéneo de recién nacidos con retraso de crecimiento intra-uterino asimétrico. También se analizó el efecto de los cambios en el status del cinc en el crecimiento y las concentraciones séricas de leptina. Población y método: Se diseñó un ensayo clínico randomizado y doble ciego, con el fin de detectar diferencias en el crecimiento entre los grupos recibiendo cinc o placebo, durante los seis primeros meses de vida. 31 niños fueron incluidos en el grupo cinc (n = 14) (38,8 ± 1,4 semanas edad gestacional, 2.171 ± 253 g peso) o grupo placebo (n = 17) (38,9 ± 1.1 semanas edad gestacional, 2.249 ± 220 g peso). El grupo cinc recibió un suplemento de 3 mg de cinc elemental por día (en forma de sulfato de cinc). Resultados: No hubo diferencias significativas entre ambos grupos en cuanto a las medidas antropométricas a lo largo del período de estudio. Se observó un efecto significativo del grupo de estudio, en las concentraciones de cinc en el pelo, pero no en las concentraciones séricas de cinc; las comparaciones post-hoc para el cinc del pelo pusieron de manifiesto que había diferencias significativas entre los grupos, en los meses 1, 2 y 6 de edad. Los cambios en las concentraciones de cinc en el suero y en el pelo, desde el inicio del estudio hasta los 6 meses, mostraron correlaciones estadísticamente significativas con los cambios en peso/edad y longitud/edad (puntuación típica), en el grupo que recibió el suplemento de cinc. Los cambios en las concentraciones séricas de leptina durante el seguimiento, mostraron correlaciones estadísticamente significativas para la suma de 4 pliegues y para peso/edad (puntuación típica), en el grupo placebo. Los cambios en las concentraciones de cinc en el pelo mostraron correlaciones estadísticamente significativas con los cambios en las concentraciones séricas de leptina, desde el inicio del estudio hasta los 6 meses de seguimiento. Conclusiones: En un grupo homogéneo de niños con retraso de crecimiento intra-uterino asimétrico, el suplemento de cinc a una dosis de 3 mg/día, no origina mejora significativa en el crecimiento en peso y longitud. Los cambios en el status de cinc se relacionaron con los cambios en peso y longitud durante los 6 primeros meses de vida. Los cambios en las concentraciones séricas de leptina se relacionaron con los cambios en los índices antropométricos de acúmulo de grasa corporal.

This article is a transcription of an electronic symposium in which some active researchers were invited by the Brazilian Society for Neuroscience and Behavior (SBNeC) to discuss the last decade's advances in neurobiology of learning and memory. The way different parts of the brain are recruited during the storage of different kinds of memory (e.g., short-term vs long-term memory, declarative vs procedural memory) and even the property of these divisions were discussed. It was pointed out that the brain does not really store memories, but stores traces of information that are later used to create memories, not always expressing a completely veridical picture of the past experienced reality. To perform this process different parts of the brain act as important nodes of the neural network that encode, store and retrieve the information that will be used to create memories. Some of the brain regions are recognizably active during the activation of short-term working memory (e.g., prefrontal cortex), or the storage of information retrieved as long-term explicit memories (e.g., hippocampus and related cortical areas) or the modulation of the storage of memories related to emotional events (e.g., amygdala). This does not mean that there is a separate neural structure completely supporting the storage of each kind of memory but means that these memories critically depend on the functioning of these neural structures. The current view is that there is no sense in talking about hippocampus-based or amygdala-based memory since this implies that there is a one-to-one correspondence. The present question to be solved is how systems interact in memory. The pertinence of attributing a critical role to cellular processes like synaptic tagging and protein kinase A activation to explain the memory storage processes at the cellular level was also discussed.