Maria Esther Rio

Effect of short term refeeding on the thymus of growing rats after marginal and severe protein deprivation

Abstract The recovery of thymus of growing rats after marginal and severe protein deprivation at weaning was studied. Diets containing 15% or 20% casein were fed during a five day experimental period; age-matched control groups (36 and 45 days of age) received stock diet from weaning. At the end of the refeeding period body weight (bw) was determined and animals were killed. Thymus was removed; weight and cell number were determined. The mature T cell population was characterized by indirect immunofluorescence using the monoclonal antibody W3/13. Body weight (g) and thymus weight (mg) increased significantly in all the experimental groups after 5 days of refeeding; in spite of this none of them reached the values of their age-matched control (p 0.75 (g) were observed in the marginal protein deprived rats refed with 15% or 20% protein diet when compared to their respective age-matched control; thymus weight of severe depleted animals remained significantly lower. All experimental groups showed higher number of thymocytes tran the respective protein deprived group; after refeeding with both diets only the marginal deprived group reached the values of the age-matched control. None of the refed groups reached the percentage and absolute number of mature W3/13 + T cell population found in the respective well nourished controls; nevertheless, the percentage of W3/13 + cells was significantly higher in the groups fed the 20% protein diet. These results confirm the interaction between dielary protein concentration and the degree of wasting; they also point to the time of refeeding as all important factor since a short period is enough to reverse the damage produced by marginal protein malnutrition on cellular proliferation, but not on the appearance of specific antigenic determinants.

The molar ratio of retinol-binding protein to transthyretin in the assessment of vitamin A status in adults. Proposal of a cut-off point.

Abstract The molar ratio of retinol-binding protein to transthyretin (RBP:TTR) has been proposed as an indirect method to assess vitamin A status in children with inflammation. Neither reference values nor appropriate cut-off point are available for adults. RBP, TTR and retinol were determined in plasma from 100 healthy adults and 31 low-risk surgical patients with no inflammatory response. RBP:TTR percentile distribution from 99 healthy adults with plasma retinol ≥0.7 μmol/l was: 2.5th = 0.24; 5th = 0.31; 10th = 0.32; 25th = 0.41; 50th = 0.47; 75th = 0.54; 90th = 0.67; 95th = 0.78 and 97.5th = 0.81. In order to define a cut-off point, receiver operating characteristic (ROC) curve was constructed, using plasma retinol as gold standard. ROC curve was based on data from the 131 studied subjects, 11 of whom (8.4%) were classified as deficient on the basis of plasma retinol <0.7 μmol/l. According to ROC curve criteria, RBP:TTR ratio was considered a good test, the area under the curve being 0.822, p<0.001. A cut-off-point of ≤0.37 is proposed to detect vitamin A deficiency in adults, since it allows reaching high sensitivity (81.8%), specificity (79.2%) and predictive value (79.4%). The proposed cut-off point falls between 13th and 14th percentiles.

Lactic Acid Fermented Products as Vehicles for Probiotics

For thousands of years microbial cultures have been used to ferment foods and prepare different kind of products. Unstable primary foodstuffs such milk, meat and vegetables can be conserved for relatively long periods of time (Table 1), maintaining their nutritious and caloric value by the use of lactic acid fermentation. Several traditional soured milks such as kefir, koumis, leben and others were used as foods and often therapeutically, before the existence of the actual knowledge on probiotics. The origins of cultured dairy products can be traced in the Bible and the sacred books of Hinduism. Metchnikoff at the beginning of the XX century proposed the beneficial effects of the lactic acid bacteria (LAB) on health and longevity.

Déficit de vitamina A en una población infantil de alto riesgo social en Argentina

Introduccion: La vitamina A es muy importante en su rol nutricional y es un factor critico en la salud y supervivencia del nino. Objetivo: El objetivo de este trabajo fue evaluar los niveles de vitamina A en ninos provenientes de hogares con necesidades basicas insatisfechas (NBI) de tres areas del pais y determinar las relaciones que pudieran existir entre esos niveles y ciertas variables clinicas, antropometricas, alimentarias y socieconomicas. Poblacion: Todos los ninos de 0,5 a 2,11 anos de hogares con NBI que concurrie-ron de septiembre a diciembre de 1995 a determinados centros de salud apara control con los medicos involucrados en este estudio. Fueron criterios de exclu-sion los ninos con enfermedades croni-cas o actuales, no asi los desnutridos. Se estudiaron en Buenos Aires 268 ninos, en Chaco 140 ninos y en corrientes 195 ninos. Material y metodos: En cada centro de salud el medico realizo: recoleccion de informacion mediante: A) un cuestiona-rio con datos personales, antecedentes nutricionales, antecedentes patologicos, inmunizaciones, B) examen clinico y evaluacion antropometrica, c)extraccion de muestras de sangre de cada nino para dosaje de retinol plasmatico de acuerdo a tecnicas estandarizadas. El limite inferior normal de retinol fue establecido en 20 ug/dl. Resultados: Se encontro una alta prevalencia de deficit de vitamina A en 26%, 32% y 46% de los ninos estudia-dos en Buenos Aires, Chaco y Corrientes, respectivamente, no se encontraron relaciones entre el retinol y las variables socioeconomicas, de morbilidad y nutricionales. Conclusioens: Los resultados sobre 603 ninos estudiados revelan severo deficit de vitamina A en ninos de 0,5 a 2,11 anos de edad pertenecientes a hogares con NBI en tres areas estudiadas en Buenos Aires, Chaco y Corrientes

Vitamin A and zinc levels in gastroenterological surgical patients: Relation with inflammation and postoperative complications

INTRODUCTION It is accepted that even mild nutrient depletion may affect the evolution of the surgical patient. OBJECTIVE To evaluate the influence of preoperative levels of plasma retinol and zinc on postoperative evolution of surgical patients; to evaluate the influence of inflammation on both level markers. METHODS Plasma retinol and zinc were determined in 50 patients before programmed gastroenterological surgeries. To detect global malnutrition BMI and weight loss percentage (WL%) were included. C-reactive protein (CRP) was included as inflammation marker. During follow up postoperative complications were recorded. The present analysis was carried out in 43 patients with complete information. RESULTS Low retinol values (< 20 μg/dl) were founded in 3 cases and low Zn values (< 85 μg/dl) in 20 cases, being 9 of them indicative of severe deficiency (< 70 μg/dl). Postoperative complications were recorded in 17 patients; patients with complications presented lower values of plasma Zn (78.4 ± 25.8 vs. 87.8 ± 25.7 μg/dl) and retinol (36.9 ± 14.5 vs. 49.7 ± 20.6; P = 0.0318) than those with no complications; the number of patients with complications decreased when retinol and Zn ranges increased. No relation between BMI or WL% and appearance of complications was founded; patients with higher WL% were those with higher usual weight. Inflammation affected both markers: retinol dropped from 50.1 ± 17.2 to 44.0 ±20.8 and to 23.7 ± 4.0 μg/dl for CRP ranges of < 0.5, 0.5-3.9 and ≥ 4 mg/dl, respectively (p = 0.0193); levels of zinc fell from 90.1 ± 17.8 to 85.2 ± 29.9 and to 55.0 ± 25.9 μg/dl for the same CRP ranges (P = 0.0195). Zn level influenced retinol level, dropping to 33.1 ± 11.7 μg/dl of retinol in the Zn severe deficiency group (P = 0.0386). CONCLUSIONS The obtained results confirm the influence of vitamin A and zinc on postoperative evolution of the surgical patient, while alert about the interrelationships among vitamin A, zinc and inflammation, which lead to difficulty to establish the real source of deficiencies. Beyond these difficulties, retinol and zinc plasma levels determine the nutrient availability for the body and appear as promissory markers of surgical risk.

Apolipoproteins A-I and B as Predictors of Complications in Gallbladder Lithiasis Surgical Patients

Specific serum proteins have been traditionally used in the assessment of protein-energy malnutrition. Some short half-life serum proteins have been related to the appearance of postoperative complications in surgical patients with low-risk pathologies that, far from undernutrition, showed a trend toward overweight and obesity. Apolipoproteins have been proposed as potential tools to assess protein status and nutritional recovery, so we investigated apolipoproteins A-I and B as new tools with prognostic value to detect postoperative complications. We analyzed the interrelation between apolipoproteins level and the appearance of complications after programed surgical procedures of gallbladder lithiasis. Assessment was performed, and postoperative complications were recorded in 52 patients (39 women and 13 men, age range = 21-69 y). Assessment included measurements of weight and height and determinations of apolipoprotein A-I and B by quantitative radial immunodiffusion on gel layers. Apolipoproteins levels showed no statistical differences between complicated and uncomplicated patients. The apolipoproteins included in this study did not predict surgical complications because abnormal values were not associated with the presence of complications in this kind of patient.

Hypothesis on the time course of antigen dependent changes in lymphoid organs proved by experimental data of depleted growing rats'mesenteric lymph nodes

The results described in this paper partially agree with the hypothesis that mesenteric lymph nodes (MLN) of depleted growing rats recover their antigen specific determinants after the oral administration of 20% casein for 5-9 days following the time course of antigen dependent changes observed in virgin lymph nodes. With respect to the 39 days old control group, depleted MLN showed a highly diminished number of mature T cells (W3/13+) as well as surface and intracellular alpha heavy chain (alpha s and alpha cit). The oral administration of a 20% casein diet during 5 days tends to restore the appearance of these determinants; however, normal values were not attained even if refeeding was continued for 9 days. The discrepancy between the proposed hypothesis and the observed results might be ascribed to: a) defective migration of T cells from thymus; b) the diminished number of TH cells involved in terminal differentiation; c) inability of B cells to respond to T cell-derived factors.

Theory about interrelationships between macromineral nutrients and growth rate during recovery from undernutrition

Previous papers of our group have reported that, in the first stages of nutritional recovery, the needs of undernourished infants, in terms of Protein Calories percentage (P%) were higher than normal, and similar to those of other mammals which double their birth weight faster than man. During this period, a high dietary P% produces an accelerated catch-up growth. Therefore, Calcium and Phosphorus balances increase proportionally to weight gain rate (WGR), and Calcium retention per gram of new tissue is dependent on dietary Calcium/Protein ratio. On the other hand, Bernhart demonstrated that there was a direct correlation between the growth rate of the sucklings of several species, including humans, and the percentage of protein and ash in the fluid milk. As a consequence of these facts, we assume that during catch-up growth, in order to attain a normal body composition, dietary level of essential minerals must be related to factors affecting weight gain. These relationships suggest the hypothesis that, during the recovery from undernutrition, in order to meet the needs of the catch-up growth allowed by the Protein/Calories ratio, Calcium and Phosphorus milk concentrations would be in relation to the Protein/Calorie concentration. In this way, Calcium and Phosphorus concentrations might be the limiting factors for attaining a normal body composition. This hypothesis might also be generalized to other minerals in order to prevent them from becoming the limiting factors for attaining a normal body composition.