ABSTRACT
Vitamin E usually works as a biological antioxidant, preventing the oxidation of polyunsaturated fatty acids and proteins, for which it is considered an important protective factor in the development of diseases related to oxidative processes. Beyond its antioxidant properties, it has been involved also in genetic expression, mitochondrial metabolism, cell differentiation and immune system regulation. From the point of view of its antioxidant protection properties, values > or = 1200-1300 micrograms/dL are considered optimum levels (standardized according to plasmatic lipid levels). In relation to the beneficial advantage effects of vitamin E on primary or secondary atherosclerotic disease, data are not conclusive. Vitamin A is part of the organism's defense barrier against free radicals. Its antioxidant mechanism of action includes scavenging of single oxygen and thiol free radicals, and it also could be related to processes that involve genetic expression and cell differentiation. As an antioxidant, vitamin A plasmatic levels > or = 80 micrograms/dL are considered optimal. The highest risk of using this vitamin is related to its acute or chronic toxicity. Quantification of serum vitamin E (alpha tocopherol) and vitamin A (retinol) are made by high performance liquid chromatography (HPLC), method of high precision, sensitivity and reproducibility.
Subject(s)
Humans , Infant , Adult , Antioxidants , Vitamin A , Vitamin E , Antioxidants , Carotenoids , Chromatography , Cardiovascular Diseases/prevention & control , Hematologic Diseases/drug therapy , Free Radical Scavengers , Immune System , Inflammation/prevention & control , Lipid Peroxidation , Neoplasms , Nutritional Requirements , Oxidation-Reduction , Plants , Specimen Handling , Vitamin A , Vitamin EABSTRACT
En algunos individuos con limitaciones funcionales y/o en ciertas áreas de trabajo, la determinación precisa de talla y peso presenta dificultades. Existe sin embargo, la alternativa de estimar estas variables a través de mediciones de segmentos corporales como la altura de la rodilla (AR) y la circunferencia media del brazo (CMB). En una muestra de 113 niños venezolanos de ambos sexos, clínicamente normales, de edades entre 9 y 14 años, se evaluaron las ecuaciones sugeridas por los Laboratorios Ross para estas estimaciones. Se evidenció la necesidad de ajustar estas ecuaciones a la población en estudio mediante análisis de regresión múltiple. Esto permitió generar tablas de talla y peso estimados a partir de AR y CMB para niños venezolanos.