Nora Slobodianik

Nutritional status in patients with HIV infection and AIDS.

The aim of this study was to evaluate the nutritional status of adults with HIV infection or with AIDS through the use of biochemical parameters. The study was performed on 43 patients (19 HIV+ and 24 AIDS patients), between 26 and 44 years of age, from low and medium socioeconomic status, with access to health care services; 35 patients were under highly active antiretroviral therapy (HAART) treatment. Body weight and height were determined, and the Body Mass Index calculated (kg/m2). Blood samples were collected from fasting patients. Plasma cholesterol (total, HDL and LDL), triacylglycerol, total protein, apolipoproteins A-I and B, albumin, transthyretin, retinol binding protein, and ceruloplasmin concentrations were determined. Plasma levels of zinc, copper, and selenium were determined in a haemolysis-free sample by flame atomic absorption spectrometry. Statistical analyses were performed with the Students t-test. AIDS patients showed changes in biochemical parameters, particularly an increase in fibrinogen and a trend to decreased transthyretin levels. These findings stress the importance of the inclusion of functional biochemical parameters in the periodic evaluation of these patients. This would allow an early assessment of the need for appropriate nutritional support, implemented along with the specific retroviral treatment. This would aim at delaying the progression of the disease, and might improve the prospects of survival and quality of life.

Potentiation of omega-3 fatty acid antidepressant-like effects with low non-antidepressant doses of fluoxetine and mirtazapine.

Despite the advances in psychopharmacology, the treatment of depressive disorders is still not satisfactory. Side effects and resistance to antidepressant drugs are the greatest complications during treatment. Based on recent evidence, omega-3 fatty acids may influence vulnerability and outcome in depressive disorders. The aim of this study was to further characterize the omega-3 antidepressant-like effect in rats in terms of its behavioral features in the depression model forced swimming test either alone or in combination with antidepressants fluoxetine or mirtazapine. Ultimately, we prompted to determine the lowest dose at which omega-3 fatty acids and antidepressant drugs may still represent a pharmacological advantage when employed in combined treatments. Chronic diet supplementation with omega-3 fatty acids produced concentration-dependent antidepressant-like effects in the forced swimming test displaying a behavioral profile similar to fluoxetine but different from mirtazapine. Fluoxetine or mirtazapine at antidepressant doses (10 and 20 mg/kg/day, respectively) rendered additive effects in combination with omega-3 fatty acid supplementation (720 mg/kg/day). Beneficial effects of combined treatment were also observed at sub-effective doses (1 mg/kg/day) of fluoxetine or mirtazapine, since in combination with omega-3 fatty acids (720 mg/kg/day), antidepressants potentiated omega-3 antidepressant-like effects. The antidepressant-like effects occurred in the absence of changes in brain phospholipid classes. The therapeutic approach of combining omega-3 fatty acids with low ineffective doses of antidepressants might represent benefits in the treatment of depression, especially in patients with depression resistant to conventional treatments and even may contribute to patient compliance by decreasing the magnitude of some antidepressant dose-dependent side effects.

Nutrition disorders and immunologic parameters: study of the thymus in growing rats

OBJECTIVES We studied the effect of a low-quality dietary protein on cellular proliferation and maturation in the thymus of growing rats over time. METHODS After weaning Wistar rats were fed a diet containing 6.5 g/100 g of corn flour for 6, 10, 18, and 45 d (M groups). For comparison, other rats were fed a diet containing 6.5 g/100 g of casein (Cas groups), and well-nourished age-matched control rats were fed a commercial laboratory diet (C groups). Food intake, body weight, thymus weight, total number of thymocytes, and the percentages of CD43(+) and Thy1(+) thymocyte phenotypic antigen determinants were measured. RESULTS M versus Cas and C groups showed significant differences (P < 0.01) in body and thymus weights after 6 d of feeding, and the total number of thymocytes and the percentages of CD43(+) and Thy1(+) were significantly lower after 10 d of feeding. The results indicated that consuming a cereal diet for short or long periods causes thymus atrophy in growing rats, with significant reductions in the total number of T-cells concomitant with increases in the number of immature thymocytes. CONCLUSIONS The data showed that, in addition to low-protein concentration, low-quality dietary protein is a limiting factor in certain steps of cellular intrathymic pathways, probably related to the requirement of specific amino acids for optimal immune response.

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.

Total salivary IgA, serum C3c and IgA in obese school children

Studies of the immunologic function in adult obese humans and experimental models indicate that excess adiposity is associated with impairments in host defense mechanisms. The aim of this work was to analyze the secretory and humoral immune system in obese children (n = 105, 55 boys, 50 girls ), between 6 and 13 years of age. Samples of non-stimulated saliva and whole blood were collected from fasting patients. Total salivary IgA (IgAsal), serum C3 complement (C3c) and Immunoglobulin A (IgA) were determined by quantitative radial immunodifussion on agar gel layers ( Diffu-plate, Biocienti;fica SA ). Results, expressed as mg/dl, were compared to laboratory reference values from healthy children of either sex in the same range of age that belong to the same socioeconomic class (n = 60). Data (Mean +/- 1 SD) of the whole population were: IgAsal: 11.4 +/- 4.8 vs 14.8 +/- 6.9; C3c: 190.7 +/- 53.1 vs 126.3 +/- 45.5; IgA: 194.5 +/- 101.5 vs 157.2 +/- 19.9. Data distribution showed higher frecuencies near the zone of the highest reference values for serum C3c; when results of IgA and IgAsal were expressed as percentage of the mean reference value, 51% and 48.6% of the whole studied population presented data lower than 100% and 75% respectively. These results show a compromised secretory immune system without incidence of clinical symptoms and infections, whereas humoral immunity might not be profoundly affected.

Immunoglobulin A levels in southern elephant seal (Mirounga leonina) milk during the suckling period

Immunoglobulin A (IgA) levels in milk samples from southern elephant seals at King George Island, Antarctica are reported. IgA levels were determined throughout the suckling period (approximately 23 days). The IgA concentration in southern elephant seal milk was lower than in other mammals and, unlike most mammalian milk, was not high during early lactation. There was not a definite pattern in IgA levels, which fluctuated within narrow limits throughout the suckling period (mean +/- SD, 30.81 +/- 6.38 mg IgA/100 g milk). If IgG was present, its level was too low to be detected by the method used. This is the first evidence in Southern elephant seal of the possibility of transmission of passive immunity after birth involving secretion of IgA in the milk.

IMMUNOGLOBULIN M SERUM LEVELS IN FEMALES AND PUPS OF SOUTHERN ELEPHANT SEAL (MIROUNGA LEONINA) DURING THE SUCKLING PERIOD

This paper reports Immunoglobulin M (IgM) levels in serum samples from eight female-pup pairs of southern elephant seals (Mirounga leonina), at King George Island, Antarctica. IgM levels were determined on sera obtained from sequential sampling throughout the suckling period (approximately 23 days). The IgM concentration in southern elephant seal serum was measured by single radial immunodiffusion on agarose plates. Female IgM levels (123.5-613.0 mg/dL, n = 8) were significantly higher than pup levels (5.9-123.6 mg/dL, n = 8). Both groups showed an increasing trend throughout the entire suckling period, with significant differences in relation to stages of lactation. Pup IgM levels on the first day of life (mean +/- SD, 7.6 +/- 2.9 mg/dL, n = 3) suggest that endogenous synthesis takes place before birth.

Southern elephant seals: IgM concentration in milk of cows and serum of their pups

Abstract Serum and milk Immunoglobulin M (IgM) concentrations in 11 mother-pup pairs were measured in southern elephant seals (Mirounga leonina) throughout lactation during 2 breeding seasons at King George Island. Samples were obtained sequentially throughout the suckling period (approximately 23 days). The IgM concentration was measured by single radial immunodiffusion on agarose plates. Milk IgM concentrations showed significant differences throughout lactation, with the highest concentrations on the 1st day (x=989.7 mg/dL skimmed milk; SD=433.2) followed by a sharp fall during the next 3–6 days of the suckling period. The ratio of milk IgM/serum IgM concentrations from mothers ranged from 0.21 to 21.92, with highest values in the 1st day of lactation (x=8.25, SD=5.4) and a decrease in concentration as lactation progressed. This was due to the fact that, throughout lactation, milk IgM concentrations fell while serum IgM values showed an increasing trend. Pups showed the lowest serum IgM values in the 1st day of the suckling period (x=13.0 mg/dL, SD=4.3) with an increasing trend as lactation progressed. Despite the high IgM concentrations of milk at day 1 of lactation, by 1 week of age pups had serum IgM concentrations only slightly greater than at birth. This suggests that much of this Ig was newly formed and little or no milk IgM was absorbed during the 1st week. Possibly, the function of ingested IgM is to provide local immunity in the pups gut, during the first few days of postnatal life.

Potential markers of the nutritional status in an experimental model.

The activity of adenine deaminase (ADA) and purine nucleoside phosphorylase (PNP) as potential nutritional markers was analyzed in an experimental model. Weanling Wistar rats were fed a protein-free diet ad libitum to obtain a severe degree of wasting. An age-matched control group received a stock diet. At the end of the experiment, body weight (BW) and thymus weight (TW) were determined. Activity of ADA and PNP was determined on thymocytes of protein-deprived and control rats; the results, expressed as micromoles of uric acid x 10(-1)/W (W = TW/BW(0.75)), were 17.0 +/- 2.6 versus 9.1 +/- 3.0 for ADA and 11.5 +/- 4.2 versus 3.9 +/- 1.0 for PNP (P < 0.01). These results suggest that the nutritional stress provoked by the administration of a protein-free diet from weaning onward affects the development of thymocytes. Moreover, the increase in the activity of ADA and PNP would be an alternative mechanism to avoid the accumulation of high levels of deoxynucleotides, which would be toxic for T lymphocytes. However, some investigators have observed an increase of ADA activity in human serum under some adverse conditions; for this reason and taking into account the present findings, it would be interesting to determine the relation between the activity of ADA and PNP in thymocytes and serum in experimental models to analyze and propose these biochemical parameters as potential and useful markers of nutritional status; it also would be interesting to test this relation in human studies.

Inflammatory biomarker profile in children with cystic fibrosis: preliminary study

The aim of this preliminary study was to determine specific proteins, related to inflammation process and nutritional status as well as to total antioxidant capacity, in children suffering from cystic fibrosis (CF). The study was performed on 17 nonhospitalized children (12 boys and 5 girls) with CF aged 3 months to 10 years, who were assisted at the Nutrition Service from Pedro de Elizalde Hospital. Transferrin, transthyretin, ceruloplasmin (Cp), haptoglobin, C-reactive protein (CRP) and fibrinogen were measured by single radial immunodiffusion techniques. Total antioxidant capacity (TAC) was determined by a decolorization assay. Statistical analyses were performed by the Students t test. Transferrin and transthyretin values were lower in CF patients in comparison with data obtained from healthy children (reference group, RG). The decreased transferrin concentration and the tendency towards low plasma transthyretin values suggested an abnormal nutritional status. However, higher Cp and haptoglobin levels were shown in patients than in RG. The fact that 23 and 50% of patients exceeded the desirable values for fibrinogen (<285.0 mg/dl) and CRP (<0.2 mg/dl), respectively, should be highlighted. The TAC (mM; Trolox equivalents) was shown to be lower in the CF group than in RG. The diminished TAC concomitant with an increased plasma Cp concentration would exacerbate the inflammatory status and could explain the depression of the immune system. These preliminary results could explain the need to include biochemical and functional parameters in the early nutritional status evaluation in CF patients in order to use appropriate nutritional and pharmacological therapies and consequently to improve their survival and quality of life.