Mardone Cavalcante França

Socioeconomic conditions as determining factors in the prevalence of systemic and ocular toxoplasmosis in Northeastern Brazil

OBJECTIVE To determine the prevalence of systemic and ocular toxoplasmosis among 1024 students in the city of Natal, Northeastern Brazil, and correlate it with demographic, socioeconomic and epidemiological risk factors. METHODS The study population was randomly selected, asked to fill out a questionnaire, provide a blood sample for IgG and IgM (MEIA) serology and a hemogram, and undergo an eye examination. RESULTS The seroprevalence for IgG was 46% (95% CI = 42.9-49.2%) and that for IgM was 1.4% (95% CI = 0.8-2.4%). The prevalence of ocular lesions was 1.15% (95% CI = 0.6-2.0%). In the univariate analyses, confirmed by multivariate analysis, the socioeconomic conditions were determinants in the prevalence of systemic and ocular toxoplasmosis (mothers schooling = literacy/OR = 2.9 and p < 0.001). CONCLUSIONS The prevalence of systemic toxoplasmosis, although high, was lower than that found in studies performed in the South and Southeast of Brazil, and the incidence of ocular lesions was totally different, being lower by a factor varying from 5 to 17. Although important epidemiological variables, such as owning a cat, drinking unfiltered water or having had contact with lakes or rivers, were found to be correlated with toxoplasmosis in the preliminary analysis, they lost their influence when included in the logistic model. However, further studies must be undertaken to identify the reasons for these findings, including the determination of the strains of Toxoplasma gondii encountered in different regions of the country and the sources of the water utilized by these populations.

Positive effects of zinc supplementation on growth, GH, IGF1, and IGFBP3 in eutrophic children.

Abstract Zinc is an essential micronutrient for growth and development. Its deficiency causes growth retardation in children and adolescents. The present study analyzes the effect of zinc on growth hormone (GH) secretion, insulin-like growth factor 1 (IGF1), and insulin-like growth factor-binding protein 3 (IGFBP3) in normal children before puberty. Thirty normal children were studied, 15 boys and 15 girls, aged 6–9 years. They were orally supplemented with 5 mg Zn/day for 3 months and 0.06537 mg Zn/kg body weight was injected before and after oral supplementation. Dietary intake and anthropometric measurements were assessed at baseline and end of study. Plasma GH levels increased during intravenous zinc administration and IGF1 and IGFBP3 increased after oral zinc supplementation. There was a positive correlation between the areas under the curves of GH and zinc after oral supplementation. Zinc supplementation was possibly effective in improving the body zinc status of the children, secretory levels of IGF1 and IGFBP3, GH potentialization, and height.

Oral zinc supplementation decreases the serum iron concentration in healthy schoolchildren: a pilot study.

The recognized antagonistic actions between zinc and iron prompted us to study this subject in children. A convenience sample was used. Thirty healthy children between 8 and 9 years of age were studied with the aim of establishing the effect of a 3-mo oral zinc supplementation on iron status. Fifteen individuals were given a placebo (control group), and 15 were given 10 mg Zn/day (experimental group). Blood samples were collected at 0, 60, 120, 180 and 210 min after a 12-h overnight fast, before and after placebo or zinc supplementation. This supplementation was associated with significant improvements in energy, protein, fat, carbohydrate, fiber, calcium, iron, and zinc intake in accordance with the recommendations for age and sex. The basal serum zinc concentration significantly increased after oral zinc supplementation (p < 0.001). However, basal serum iron concentrations and area under the iron curves significantly decreased in the experimental group (p < 0.0001) and remained at the same level throughout the 210-min study. The values obtained for hemoglobin, mean corpuscular volume, ferritin, transferrin, transferrin saturation, ceruloplasmin and total protein were within normal reference ranges. In conclusion, the decrease in serum iron was likely due to the effects of chronic zinc administration, and the decrease in serum iron was not sufficient to cause anemia.

Sensitivity of zinc kinetics and nutritional assessment of children submitted to venous zinc tolerance test.

Objective: The purposes of this study were to investigate the kinetics of zinc in schoolchildren between the ages of 6 and 9 years, of both sexes, and to verify its sensitivity in detecting alterations in body zinc status. Methods: Nutritional assessment was performed by body mass index. Food intake, venous zinc tolerance test, and zinc kinetics were carried out before and after 3-month oral zinc supplementation. Results: Of the 42 children studied, 76.2% had healthy weight. Only energy, calcium, and fiber intake were suboptimal before and after oral zinc supplementation. Serum zinc and total-body zinc clearance, although at normal levels, increased significantly after zinc supplementation. Conclusion: We concluded, therefore, that kinetics is a sensitive tool for detecting changes in body zinc status, even in children without a deficiency of this mineral. Furthermore, kinetics showed a positive response to supplementation and may be a sensitive parameter for evaluating the efficacy of this therapy.

Effect of Diet Intervention and Oral Zinc Supplementation on Metabolic Control in Berardinelli-Seip Syndrome

Background/Aims: Berardinelli-Seip syndrome (BSS), also termed congenital generalized lipodystrophy or congenital generalized lipoatropic diabetes, is a rare autosomal recessive disease characterized by the nearly complete absence of metabolically active adipose tissue from birth, extreme insulin resistance, diabetes mellitus, and hepatomegaly. The aim of this study was to evaluate the effect of diet intervention and oral zinc supplementation on the metabolic control of BSS patients. Methods: During a 3-month period, 10 BSS patients received individualized diets and oral zinc supplementation. Food intake, clinical laboratory parameters, serum zinc and leptin, and plasma C-peptide concentrations were evaluated at the beginning of the study and after 3 months. Results: At the beginning of the study, all patients had elevated energy, protein, total fat, carbohydrate, calcium, iron, and zinc intakes. After 3 months, all of these parameters had decreased. Total fiber intakes remained low before and after diet intervention and oral zinc supplementation, and plasma levels of fasting glucose remained high. In contrast, glycated hemoglobin decreased significantly. Plasma leptin, C-peptide, and serum zinc levels increased during venous zinc tolerance testing, but there were no significant differences between the 2 curves obtained before and after diet intervention and oral zinc supplementation. Conclusions: Diet intervention and oral zinc supplementation were effective at controlling energy consumption, macronutrients, and glycated hemoglobin. Zinc likely acts as an adjunct therapy, thereby improving the effectiveness of leptin.

Zinc pharmacokinetic parameters in the determination of body zinc status in children

Background/Objectives:Serum or tissue zinc concentrations are often used to assess body zinc status. However, all of these methods are relatively inaccurate. Thus, we investigated three different kinetic methods for the determination of zinc clearance to establish which of these could detect small changes in the body zinc status of children.Subjects/Methods:Forty apparently healthy children were studied. Renal handling of zinc was investigated during intravenous zinc administration (0.06537 mg Zn/kg of body weight), both before and after oral zinc supplementation (5 mg Zn/day for 3 months). Three kinetic methods were used to determine zinc clearance: CZn-Formula A and CZn-Formula B were both used to calculate systemic clearance; the first is a general formula and the second is used for the specific analysis of a single-compartment model; CZn-Formula C is widely used in medical practices to analyze kinetic routine.Results:Basal serum zinc values, which were within the reference range for healthy children, increased significantly after oral zinc supplementation. The three formulas used gave different results for zinc clearance both before and after oral zinc supplementation. CZn-Formula B showed a positive correlation with basal serum zinc concentration after oral supplementation (R2=0.1172, P=0.0306). In addition, CZn-Formula B (P=0.0002) was more effective than CZn-Formula A (P=0.6028) and CZn-Formula C (P=0.0732) in detecting small variations in body zinc status.Conclusions:All three of the formulas used are suitable for studying zinc kinetics; however, CZn-Formula B is particularly effective at detecting small changes in body zinc status in healthy children.

Nutritional assessment methods for zinc supplementation in prepubertal non-zinc-deficient children

Background Zinc is an essential nutrient that is required for numerous metabolic functions, and zinc deficiency results in growth retardation, cell-mediated immune dysfunction, and cognitive impairment. Objective This study evaluated nutritional assessment methods for zinc supplementation in prepubertal non-zinc-deficient children. Design We performed a randomised, controlled, triple-blind study. The children were divided into a control group (10% sorbitol, n=31) and an experimental group (10 mg Zn/day, n=31) for 3 months. Anthropometric and dietary assessments as well as bioelectrical measurements were performed in all children. Results Our study showed (1) an increased body mass index for age and an increased phase angle in the experimental group; (2) a positive correlation between nutritional assessment parameters in both groups; (3) increased soft tissue, and mainly fat-free mass, in the body composition of the experimental group, as determined using bioelectrical impedance vector analysis; (4) increased consumption of all nutrients, including zinc, in the experimental group; and (5) an increased serum zinc concentration in both groups (p<0.0001). Conclusions Given that a reference for body composition analysis does not exist for intervention studies, longitudinal studies are needed to investigate vector migration during zinc supplementation. These results reinforce the importance of employing multiple techniques to assess the nutritional status of populations.

Kinetics of zinc status and zinc deficiency in Berardinelli-Seip syndrome.

Berardinelli-Seip syndrome (BSS) is a very rare disorder characterized by near-complete absence of adipose tissue from birth or early infancy, hypoleptinemia, hypertriglyceridemia, insulin resistance, diabetes mellitus, and other clinical signals. It is caused by mutations in AGPAT2 or Gng3lg. We evaluated 10 BSS patients and 10 healthy subjects. A single dose of 382.43 μmol zinc was administered intravenously before and after 3 months of oral zinc supplementation. Blood samples were collected from the contralateral arm at 0, 30, 60, 90, and 120 min after zinc injection. Plasma and serum were obtained to measure hematological and biochemical parameters. Urine was collected to measure creatinine, protein, and zinc. Basal serum zinc levels were similar in controls and BSS patients. However, serum zinc profiles were significant reduced in BSS patients in comparison with controls. The change in total-body zinc clearance was more significant in BSS patients, indicating that these patients had suboptimum zinc deficiency.

Serum zinc reference intervals and its relationship with dietary, functional, and biochemical indicators in 6- to 9-year-old healthy children

Background Zinc is an important cause of morbidity, particularly among young children. The dietary, functional, and biochemical indicators should be used to assess zinc status and to indicate the need for zinc interventions. Objective The purpose of this study was to determine the zinc status and reference intervals for serum zinc concentration considering dietary, functional, and biochemical indicators in apparently healthy children in the Northeast Region of Brazil. Design The cross-sectional study included 131 healthy children: 72 girls and 59 boys, aged between 6 and 9 years. Anthropometric assessment was made by body mass index (BMI) and age; dietary assessment by prospective 3-day food register, and an evaluation of total proteins was performed. Zinc in the serum samples was analyzed in triplicate in the same assay flame, using atomic absorption spectrophotometry. Results With respect to dietary assessment, only the intake of fiber and calcium was below the recommendations by age and gender. All subjects were eutrophic according to BMI and age classification. Zinc intake correlated with energy (p=0.0019), protein (p=0.0054), fat (p<0.0001), carbohydrate (p=0.0305), fiber (p=0.0465), calcium (p=0.0006), and iron (p=0.0003) intakes. Serum zinc correlated with protein intake (p=0.0145) and serum albumin (p=0.0141), globulin (p=0.0041), and albumin/globulin ratio (p=0.0043). Biochemical parameters were all within the normal reference range. Reference intervals for basal serum zinc concentration were 0.70–1.14 µg/mL in boys, 0.73–1.17 µg/mL in girls, and 0.72–1.15 µg/mL in the total population. Conclusions This study presents pediatric reference intervals for serum zinc concentration, considering dietary, functional, and biochemical indicators, which are useful to establish the zinc status in specific groups. In this regard, there are few studies in the literature conducted under these conditions, which make it an innovative methodology.