Effect of maternal dietary amino acid pattern on rat offspring.

The effect of lifetime feeding to gravid rats of diets containing different indispensable amino acid patterns on body and brain composition of the offspring was studied. Two groups of rats were fed, from weaning to delivery, either experimental diet B or diet I. Both diets contained the same amount of total nitrogen (3.14%), available lysine (0.4%) and "complete protein to total protein ratio" (22.5%), but whereas diet I provided an excess of indispensable amino acids over the amount of limiting amino acid, diet B supplied all of the indispensable amino acids in marginal amounts and in a rather well balanced pattern. The nitrogen content of diet B was matched to the nitrogen content of diet I by addition of a mixture of dispensable amino acids. A control group fed stock diet (C) was run simultaneously. Birth body weight, carcass nitrogen to water ratio, and brain weight of pups were significantly lower in B than in I. The figures for I were not significantly different from the controls. Brain DNA content in B was significantly lower than in C, but in I it was lower than for both B and C. Nitrogen to water ratio and brain DNA content of group B were low when compared to the standard curves for our colony; however, DNA content was normal for the degree of body development. On the other hand, in group I brain DNA was preferentially affected, as if body and brain maturity were dissociated.

Immunoglobulin A level in human milk from mothers delivering preterm.

Little information is available on immunoglobulin content of milk from mothers of preterm babies. In this study we have measured IgA levels in samples from preterm and term mothers during the 1st month postpartum. The concentration of IgA tended to be constant in the preterm group (about 251 mg/dl) while it showed a decreasing trend in the term group (from 212.8 +/- 19.9 to 171.6 +/- 12.8 mg/dl). From day 10 onward IgA levels in preterm milk were significantly higher than in term milk (p less than 0.002). These findings support the idea that premature infants fed their own mothers' milk would benefit from more stable levels of IgA, at a time when their mucosal immune system is poorly developed.

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.

[Nutritional evaluation of protein concentrates of beans (Phaseolus vulgaris) and lentils (Lens esculenta)]. / Evaluación nutricional de concentrados proteicos de porotos (Phaseolus vulgaris) y de lentejas (Lens esculenta).

The composition and nutritive value were determined in navy bean meal (Phaseolus vulgaris) and lentil meal (Lens esculenta), and in their respective protein concentrates obtained through extraction followed by isoelectric precipitation. Sulfur amino acids per gram of nitrogen were lower in the concentrates than in the meals, while there was no difference for lysine and threonine. The white bean protein concentrate had a lower biological value than the meal but better digestibility, although trypsin inhibitor concentration was unchanged. Digestibility greatly improved with heating but it did not increase beyond 81% even after autoclaving. Autoclaved samples supplemented with methionine reached a biological value of 83. The lentil protein concentrate also had a lower biological value than the meal but digestibility was high for both samples (91%) and remained unchanged after heating. Trypsin inhibitors were absent. After supplementing with methionine, a biological value of only 63 was obtained, due to the low level of tryptophan, the second limiting amino acid. In spite of the concentrates' lower biological value, it was proved that they equalled the meals' potential for complementing cereal, as their content in lysine and threonine is high. The concentrates have the additional advantage of allowing effective supplementation without increasing the legume-cereal ratio.

[Serum creatine phosphokinase activity: analysis of information provided by different ways of expressing the results]. / Actividad de creatin-fosfoquinasa en suero: análisis de la información suministrada por differentes formas de expresión de los resultados

An experimental model with undernourished rats fed experimental diets containing either imbalanced proteins or low amount of well balanced proteins was used to evaluate the utility of serum CPK activity determination in human malnutrition. Special attention was given on the information provided by four ways of expression of the enzymatic activity. CPK activity was expressed as: 1) Specific activity, 2) Activity per ml serum, 3) Total activity per rat and 4) Total activity per 100 g body weight. Statystical analysis showed: a) Activity expressed per mg serum protein or per ml serum did not agree with the known physiological phenomena induced on muscle by the experimental diets: CPK activity values expressed in these ways are not useful in malnutrition studies. b) Serum total activity of CPK per rat provides a similar information to the creatinin/height index, which is easier to perform. c) Total CPK activity per 100 g body weight demonstrated to be adequate to provide information about muscle mass in rats under controlled experimental conditions. However, it is not possible to use this form of expressing CPK activity in human malnutrition, because it would be also necessary to know: plasma volumen, age, actual body weight, clinical and the nutritional background, etc., of the patient for an accurate interpretation of results.

[Determination of folates in food. Comparative and critical study]. / La determinación de folatos en alimentos. Estudio crítico y comparativo

A study on the microbiologic method for folate determination in natural products was carried out. The variables that must be considered were analyzed previous to the application of this technique, that is: nature of combinations of the compounds with vitamin activity, function and distribution of the conjugases, capacity of absorption of the polyglutamates present in foods, natural inhibitors of the conjugases and the importance of the selection of the microorganism used. Based on the preliminary investigations a modified microbiological microtechnique is proposed and its importance for some nutricional aspects is discussed.

[Enrichment of wheat flour with sunflower and soya flour for bakery products]. / Enriquecimiento de la harina de trigo con harinas de soja y girasol para la obtencion de productos de panaderia

In order to improve the nutritive value of wheat protein, with a wheat flour, defated soybean flour and sunflower seed flour were mixed on the basis of their amino acid composition. The highest nutritive value, 86 expressed as CS, was obtained with 60% wheat flour + 28% defatted soybean flour + 12% defatted sunflower seed flour. The mixture was used to prepare: a) sea-biscuits, baked in a traditional bakery oven, and b) crackers, baked in an electric endless oven. Similar products, baked with wheat flour alone, were studied as controls. Chemical composition, total lysine, methionine, cystine, threonine and available lysine content were determine on the raw flours and mixture. Protein, fats and available lysine were determined on the bakery products. The nutritive value of the latter was assessed by their NPUop from which NPUst was calculated. The results showed an increase in the protein content of the enriched bakery products up to 60% over the controls. The nutritive value of the products was lower than the calculated figure for the raw mixture. Products b had the highest NPUst (56.4), surpassing the figures for the control (33.3) and also for product a (53.5). These values agreed with the figures for lysine availability which decreased with heat according to the cooking process. These data and the good acceptability of the crackers suggest that their enrichment with soybean and sunflowers seed concentrates asayed, could help to fulfill protein requirements in children.

[Relation between erythrocyte free protoporphyrins and usual iron intake in a group of University of Buenos Aires students]. / Relación entre protoporfirinas libres en glóbulo rojo e ingesta habitual de hierro en un grupo de estudiantes de la Universidad de Buenos. Aires.

In order to analyze the interrelationships between free erythrocyte protoporphyrins and the usual iron intake in adult students, biochemical, and hematological values, and dietary daily intake, obtained using the recall method during seven days, were studied. Hematocrit (Hto.), hemoglobin (Hb) and free erythrocyte protoporphyrins (FEP) were determined in a group of 145 female university students, healthy according to the standard parameters of the Buenos Aires University Health Department. Mean iron intake was 23.0 +/- 1.5 mg per day, about 44% being provided by animal sources; 74.5% of the population was within the recommended daily intake according to FAO/WHO; only 0.7% of the population did not cover protein requirements while 35% did not cover energy needs. Hto. and Hb were below normal levels in 7.8% of the population when compared with standards according to ICNND. To obtain information about normal values to FEP, expressed as microgram/100 ml red cells (FEP% r.c.) and FEP/Hb ratio, the group of students with adequate intake of energy and proteins who had normal values for Hb and Hto. was selected. This group, including 94 women, had a mean FEP% r.c. of 15.71 +/- 7.26 and a mean FEP/Hb ratio of 0.44 +/- 0.21. There was observed an inverse correlation between FEP% r.c. and FEP/Hb with total iron intake (r = 0.80 and r = 0.78, respectively) and between FEP% r.c. and Hb concentration (r = 0.81). These results confirm the usefulness of the free erythrocyte protoporphyrins determination as a good index of iron stores and usual intake of this population.