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Background: Human milk is considered the best source of nutrition for young infants. However, if mothers cannot provide adequate breast milk or if infants are premature or have a low birth weight, breast-feeding must often be replaced or complemented with infant formulas (IFs). The interactions between infant formula components (proteins, fats, carbohydrates, vitamin and minerals) mainly affect carbohydrates and proteins (Maillard reaction, MR), but those involving proteins are especially important in products used in infant feeding because of the high protein requirements of infants. On the other hand, fatty acids (FAs) are considered important in infant development. Objectives: The aim of the present work was to test the stability of IFs made with different ingredients, analyzing the available lysine losses (for protein stability) and the FAs content and the peroxide value (for fat stability) during stored at normal and adverse conditions and to propose a faster control of that stability. Methods: Available lysine analyzed by high-performance liquid chromatography (HPLC), lipid oxidation by titrimetric method and FAs profile by gas chromatography (GC) were determined in four types of IFs prepared with intact and partially hydrolyzed proteins and different carbohydrates (lactose or maltodextrins) during storage at 4, 20 and 30 ºC for 24 months at normal water activity (Aw=0.1-0.4), and at Aw of 0.65 at 20 and 30 ºC for 4 weeks. These IFs were prepared twice (IF1 and IF2) in different batches by a Spanish dietary product company. Results: At 30ºC, available lysine losses were 40-50% in all IFs analyzed. The behavior and percentage lysine loss between 1 and 4 weeks of storage at 30 °C with Aw=0.65 was similar to those obtained after 24 months of storage at 30 °C. No significant changes were observed in fatty acid profile during storage. Oxidation was only observed in opened packs and after 4 weeks/30 °C/Aw=0.65. Conclusions: The losses of available lysine increase to higher time and storage temperatures. The FAs shows a good stability for any storage condition; however peroxide values prove more sensitive than FAs changes for evaluating fat oxidation during the storage of IFs.

Antecedentes: La leche materna es la mejor fuente nutricional para niños recién nacidos. Sin embargo, cuando las madres no pueden proveer leche, o si los niños son prematuros o tienen bajo peso al nacer, la lactancia debe ser reemplazada o complementada con fórmulas infantiles (IFs). La interacción entre los componentes de las IFs (proteínas, grasas, carbohidratos, vitaminas y minerales) principalmente afecta carbohidratos y proteínas (Reacción de Maillard, MR), pero los que implican proteínas son especialmente importantes en alimentación infantil debido a los altos requerimientos de proteína de los lactantes. Por otra parte, los ácidos grasos (FAs) son considerados importantes en el desarrollo de los niños. Objetivos: El objetivo fue evaluar la estabilidad de IFs elaboradas con diferentes ingredientes, analizando lisina útil (para estabilidad de proteínas), contenido de FAs y valor de peróxidos (para estabilidad de grasas) durante el almacenamiento bajo condiciones normales y adversas, y proponer un control más rápido de la estabilidad. Metodos: Los análisis de lisina útil por cromatografía liquida de alta resolución (HPLC), oxidación lipídica por el método de titulación y el perfil de FAs por cromatografía de gases (GC) fueron determinados en cuatro tipos de IFs preparadas con proteínas intactas y parcialmente hidrolizadas con diferentes carbohidratos (lactosa y maltodextrinas) durante el almacenamiento a 4, 20 y 30ºC por 24 meses a actividad de agua normal (Aw=0,1-0,4), y a Aw de 0,65 a 20 y 30 ºC por 4 semanas. Estas IFs fueron preparadas dos veces (IF1 y IF2 ) en baches diferentes por una empresa Española de productos dietarios. Resultados: A 30ºC, las pérdidas de lisina útil fueron de 40-50% en todas las IFs analizadas. El comportamiento y porcentaje de pérdidas de lisina entre la 1 y 4 semana de conservación a 30 °C con Aw=0,65 fue similar a las obtenidas tras 24 de almacenamiento a 30 °C. No se observaron cambios significativos en el perfil de FAs durante el almacenamiento. Oxidación solo se observo en los envases abiertos y después de 4 semanas/30 °C/Aw=0.65. Conclusiones: Las pérdidas de lisina útil incrementan a mayor tiempo y temperatura de almacenamiento. Los FAs muestran una buena estabilidad para cualquiera de las condiciones de almacenamiento, sin embargo el valor de peróxidos evidencia mayor sensibilidad que los cambios en FAs para evaluar la oxidación de las grasas durante el almacenamiento de IFs.

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INTRODUCTION: Cardiovascular diseases (CVDs) represent the main cause of morbi-mortality in western countries. Serum cholesterol levels have been related to cardiovascular disease (CVD). Egg intake has been indirectly related to the risk of developing CVD because of its high cholesterol content. OBJECTIVE: The aim of the present study was to examine the association between egg intake and CVD risk factors in adolescents, assessing the possible influence of physical activity. METHODS: We studied 380 adolescents enrolled in the HELENA (HEalthy Lifestyle in Europe by Nutrition in Adolescence) study. Food intake was estimated by 2 nonconsecutive 24 h recalls. We measured adiposity indicators, lipid profile, blood glucose and insulin levels, insulin resistance, blood pressure and cardiorespiratory fitness. A CVD risk score was computed as a measure of the overall CVD risk profile. Physical activity was objectively measured by accelerometry. Sexual development was examined. Socioeconomic and smoking statuses were obtained by questionnaire. The association between egg intake and CVD risk factors was examined using a multilevel analysis adjusted for potential confounders. RESULTS: Egg intake was not associated with lipid profile, adiposity, insulin resistance, blood pressure, cardiorespiratory fitness or the integrated CVD risk score. This lack of association was not influenced by physical activity. CONCLUSIONS: The findings of the present study suggest that egg intake is not associated with a less favorable lipid or CVD risk profile in adolescents. This lack of association is not influenced by the level of physical activity.

Introducción: Las enfermedades cardiovasculares (ECVs) suponen la principal causa de morbi-mortalidad en los países occidentales. El incremento del colesterol plasmático se ha relacionado con el desarrollo de ECV. El huevo, por su alto contenido en colesterol, ha sido indirectamente relacionado con el riesgo de desarrollar ECVs. Objetivo: Examinar la asociación entre ingesta de huevo y factores de riesgo cardiovascular en adolescentes, estudiando si dicha relación está influenciada por la actividad física. Método: Se estudiaron 380 adolescentes pertenecientes al estudio HELENA (HEalthy Lifestyle in Europe by Nutrition in Adolescence). La ingesta de alimentos se estimó mediante anamnesis nutricional de dos días no consecutivos. Se midieron indicadores de adiposidad, perfil lipídico, glucosa, insulina, resistencia a la insulina, tensión arterial y capacidad aeróbica. Se calculó un índice integrado de riesgo cardiovascular (IRCV) como medida del perfil cardiovascular global. La actividad física se midió mediante acelerometría. Se examinó el desarrollo madurativo. El estatus socioeconómico y consumo de tabaco se obtuvieron mediante cuestionario. La asociación entre ingesta de huevo y factores de riesgo de ECV se examinó mediante un modelo de regresión multinivel ajustado por factores de confusión. Resultados: La ingesta de huevo no se asoció con perfil lipídico, nivel de adiposidad, tensión arterial, resistencia a la insulina, capacidad aeróbica o IRCV (todos P > 0,05). Esta falta de asociación no estuvo influenciada por el nivel de actividad física. Conclusiones: Estos resultados sugieren que no existe asociación entre ingesta de huevo y perfil lipídico, adiposidad, resistencia a la insulina, tensión arterial, capacidad aeróbica o el IRCV en adolescentes. La actividad física no influencia dicha falta de asociación.

Introducción: Se ha afirmado que el consumo adecuado de los productos lácteos puede ser beneficioso para la prevención y el tratamiento de la diabetes mellitus tipo 2 (DMT2). Objetivos: El objetivo de esta revisión es analizar críticamente la principal evidencia científica sobre este tema. Métodos: MEDLINE, PubMed, Science Direct, SCIELO y LILACS fueron consultadas para estudios publicados en los últimos 12 años explorando los efectos del consumo de productos lácteos o sus componentes (calcio, vitamina D y magnesio) en la DMT2. Resultados y discusión: Los estudios epidemiológicos indican que el consumo de por lo menos tres porciones de productos lácteos bajos en grasa al día como parte de una dieta saludable, es crucial para reducir el riesgo de desarrollar DMT2. La mayoría de los estudios de intervención analizados reportaron efectos benéficos del aumento del calcio y de la ingestión de vitamina D en la mejora de la sensibilidad a la insulina y la prevención de DMT2. Conclusiones: Aunque el impacto del consumo de productos lácteos para tratar DMT2 necesita más investigación, el consumo de productos lácteos bajos en grasa puede ser una importante estrategia para prevenir y controlar la DMT2.

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INTRODUCCIÓN: El litotriptor electrohidráulico ha revolucionado el tratamiento de la litiasis urinaria, produce ondas de choque por descarga energética en el agua, estando asociadas éstas a un ruido. Sabemos que el daño acústico sensorioneural es ocasionado por encima de los 85 decibelios. Nuestro objetivo es determinar si el uso del litotriptor Econolith 2000 tiene algún efecto significativo en la audición de pacientes y operadores. MATERIAL Y MÉTODO: 10 pacientes fueron intervenidos con Litotricia Extracorpórea en un solo procedimiento. Se les realizó audiometría previa y dentro de 24 h post-operatorias. Todos nuestros pacientes fueron protegidos con audífonos durante el transcurso del procedimiento. Se midió la intensidad de ruido en pabellón y sitios cercanos a éste. RESULTADOS: La intensidad de ruido medida dentro del pabellón fue de 96 decibelios y fuera de él 70. No hubo evidencia de daño acústico en los pacientes protegidos con audífonos. CONCLUSIONES: El litotriptor Econolith 2000 no produce daño auditivo en pacientes protegidos por audífonos. Se desconoce el efecto a largo plazo en los operadores, quienes no siempre se protegen, por lo que es recomendable en ellos, realizar audiometría cada 6 meses (AU)

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The anorexia of aging syndrome in humans is characterized by spontaneous body weight loss reflecting diminished food intake. We reported previously that old rats undergoing a similar phenomenon of progressive weight loss (i.e., senescent rats) also display altered feeding behavior, including reduced meal size and duration. Here, we tested the hypothesis that blunted responsiveness to neuropeptide Y (NPY), a feeding stimulant, occurs concurrently with senescence-associated anorexia/hypophagia. Young (8 mo old, n = 9) and old (24-30 mo old, n = 11) male Fischer 344 rats received intracerebroventricular NPY or artificial cerbrospinal fluid injections. In response to a maximum effective NPY dose (10 microg), the net increase in size of the first meal after injection was similar in old weight-stable (presenescent) and young rats (10.85 +/- 1.73 and 12.63 +/- 2.52 g/kg body wt (0.67), respectively). In contrast, senescent rats that had spontaneously lost approximately 10% of body weight had significantly lower net increases at their first post-NPY meal (1.33 +/- 0.33 g/kg body wt (0.67)) than before they began losing weight. Thus altered feeding responses to NPY occur in aging rats concomitantly with spontaneous decrements in food intake and body weight near the end of life.

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Previous work from this laboratory suggests that animals decrease their intake of an amino acid imbalanced diet (IMB), due in part to a drop in the concentration of the dietary limiting amino (DLAA) in the anterior piriform cortex (APC). Administration of the DLAA, but not of a non-limiting amino acid into the APC, blocks the anorectic response to IMB. To our knowledge, the effects of DLAA injections on intake of a diet devoid of the DLAA (DEV), have not been examined in areas outside the APC. We hypothesized that the LH is a potential chemosensory area for DLAA. Our objectives were: (1) to determine whether injections of the DLAA threonine into the lateral hypothalamus (LH) alter intake of a threonine-devoid diet (DEV); and (2) to examine the dose-response effects of threonine injections into the LH on intake of threonine-corrected diet (COR). Administration of threonine into the LH stimulated DEV intake during the first 6 h at the 0.25 and 1-nmol doses by approximately 26 and 24%, respectively. Threonine (0.25, 2.5 nmol) did not alter COR intake at any time during the first 12 h. Our results suggest that: (1) the LH, along with the APC, likely acts as a chemosensory brain area for indispensable amino acids; and (2) both the APC and LH are part of a circuit that is involved in the short term anorectic response to amino acid imbalanced diets.

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A new method to obtain the signal associated with an electrophoretic blank is presented to be included in the calibration procedures. The signal assigned to the blank is obtained by direct integration of the background noise using extrapolated values of the base-peak width at different concentrations in order to obtain the zero concentration. Detection limits that are better adjusted to a statistical evaluation are thus implemented, as recommended by the International Union of Pure and Applied Chemistry (IUPAC). The detection limit has been examined for a series of linear alkyl benzenesulfonates (C10-C13) and total linear alkyl benzenesulfonates that are widely used in many different commercial products.

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The rationale for this study was to test the hypothesis that peripherally released peptide YY (PYY) acts in the vagal nuclear complex of the medulla oblongata to modulate vagal tone centrally. The objective was to determine whether circulating PYY gains access to and binds to the receptors identified in the dorsal vagal complex (DVC) under physiological conditions. Specific brain regions were microdissected after intravenous 125I-labeled PYY and 131I-labeled bovine serum albumin infusions to determine saturable accumulation of PYY in the brain and to determine if there were changes in plasma volume with large PYY infusions. Significant (P < 0.05) saturable binding was observed in the region of the brain stem containing the DVC and the pituitary. There were no significant changes in plasma volume in any region after the infusion of the excess nonradioactive PYY. We conclude that under physiological conditions circulating PYY binds to sites in the pituitary and portions of the DVC that have PYY receptors and an incomplete blood-brain barrier but does not bind to other areas that have an intact blood-brain barrier. Therefore this peripheral hormone may act centrally to modulate the digestive system and is a member of a novel class of gut hormones that function as central neuromodulators.

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Quantitative receptor autoradiography localized a high-affinity binding site for 125I-peptide YY to the mucosa in rabbit distal colon. Scatchard binding analysis revealed a single-affinity binding site (KD = 0.29 nM) with binding specificity similar to other peptide YY-preferring receptors (peptide YY > or = neuropeptide Y >> pancreatic polypeptide). Radioligand binding studies using colonic mucosal membranes confirmed high-affinity peptide YY binding sites (KD = 0.26 nM) with time, temperature, and protein dependence, as well as saturability characteristic of receptor-ligand binding. Selective peptide analogues showed a subpopulation of these 125I-peptide YY binding sites to resemble the Y1-type neuropeptide Y receptor. Peptide YY may exert local antisecretory effects on the colonic epithelium via these binding sites.

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A technique for experimental determination of regional myocardial blood flow and heat generation has been developed, based on a heat-clearance method. This method allows repetitive and frequent measurements of regional blood flow without necessity for biopsy or microspheres. Testing was performed on a pedicle preparation, an intact segment of left ventricular myocardium dependent on a single diagonal coronary artery and situated in situ in the left ventricular free wall. Total blood flow to the pedicle was measured by an electromagnetic flow probe. A specially designed 3-thermistor microprobe was positioned in the pedicle to continuously sense temperature changes in the subepicardium, midmyocardium, and subendocardium. The theory underlying this method is based on a heat balance that includes local myocardial heating, conduction, and convection. Comparison of the predicted time- and position-dependent temperature with that measured experimentally allows extraction of the local myocardial blood flow and heating rates. This method allows resolution of differential flows in subendocardial, midmyocardial, and subepicardial myocardium and provides quantification of dynamic flow changes in each layer in response to various stimuli such as ischemia or pressor agents, without in itself causing damage to the myocardial microvasculature. Our data show total flow, based on summation of thermally calculated regional flows, to have correlation coefficients of 0.88 with both the flowmeter and microsphere results. Resting flow values for Nembutal-anaesthetized, open-chest dogs of 0.66 ml/(g . min) compare favorably with values obtained by microsphere studies. Infusion of norepinephrine increased total flow and all layer flows, but the increase in subendocardial flow with norepinephrine was less than the increase of the other layers, perhaps accounting for the vulnerability of this region during catecholamine stress. Local myocardial heating rates in subepicardial, midendocardial, and subendocardial layers are shown to follow the same dependence on local myocardial blood flow in response to anoxic stress or norepinephrine-induced vasodilation. Specifically, local heating rate increases to a factor of 10 at flow below resting level.

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