Vitamin D-binding protein is inversely associated with the incidence of gastrointestinal and ear infections in school-age children.

Circulating 25-hydroxy vitamin D (25(OH)D) is related to decreased rates of gastrointestinal and ear infections in school-age children. Vitamin D-binding protein (DBP) transports 25(OH)D and exerts immunological functions; however, it is unknown whether DBP is associated with infectious morbidity in children. We quantified plasma DBP concentrations in 540 school-age children at the time of recruitment into a cohort study in Bogotá, Colombia and obtained daily information on infectious morbidity symptoms and doctor visits during the school year. We compared the incidence rates of gastrointestinal and respiratory symptoms across quartiles of DBP concentration by estimating adjusted incidence rate ratios (IRRs) with 95% confidence interval (CI). We also estimated the per cent of the associations between DBP and morbidity that were mediated through 25(OH)D using a counterfactual frame. Mean ± s.d. DBP concentration was 2650 ± 1145 nmol/l. DBP was inversely associated with the rates of diarrhoea with vomiting (IRR for quartiles 2-4 vs. 1 = 0.48; 95% CI 0.25-0.92; P = 0.03) and earache/ear discharge with fever (IRR for quartiles 2-4 vs. 1 = 0.29; 95% CI 0.12-0.71; P = 0.006). The DBP-morbidity associations were not mediated through 25(OH)D. We conclude that plasma DBP predicts lower incidence of gastrointestinal and ear infections in school-age children independent of 25(OH)D.

Screening for biosurfactant production by 2,4,6-trinitrotoluene-transforming bacteria.

AIMS: To isolate and identify TNT-transforming cultures from explosive-contaminated soils with the ability to produce biosurfactants. METHODS AND RESULTS: Bacteria (pure and mixed cultures) were selected based on their ability to transform TNT in minimum media with TNT as the sole nitrogen source and an additional carbon source. TNT-transforming bacteria were identified by 16S rRNA gene sequencing. TNT transformation rates were significantly lower when no additional carbon or nitrogen sources were added. Surfactant production was enabled by the presence of TNT. Fourteen cultures were able to transform the explosive (>50%); of these, five showed a high transformation capacity (>90%), and six produced surfactants. CONCLUSIONS: All explosive-transforming cultures contained Proteobacteria of the genera Achromobacter, Stenotrophomonas, Pseudomonas, Sphingobium, Raoultella, Rhizobium and Methylopila. These cultures transformed TNT when an additional carbon source was added. Remarkably, Achromobacter spanius S17 and Pseudomonas veronii S94 have high TNT transformation rates and are surfactant producers. SIGNIFICANCE AND IMPACT OF THE STUDY: TNT is a highly toxic, mutagenic and carcinogenic nitroaromatic explosive; therefore, bioremediation to eliminate or mitigate its presence in the environment is essential. TNT-transforming cultures that produce surfactants are a promising method for remediation. To the best of our knowledge, this is the first report that links surfactant production and TNT transformation by bacteria.

Alpha-linolenic acid (ALA) is inversely related to development of adiposity in school-age children.

BACKGROUND/OBJECTIVES: Studies in adults indicate that dietary polyunsaturated fatty acid (PUFA) composition may play a role in development of adiposity. Because adipocyte quantity is established between late childhood and early adolescence, understanding the impact of PUFAs on weight gain during the school-age years is crucial to developing effective interventions. SUBJECTS/METHODS: We quantified N-3 and N-6 PUFAs in serum samples of 668 Colombian schoolchildren aged 5-12 years at the time of recruitment into a cohort study, using gas-liquid chromatography. Serum concentrations of N-3 (alpha-linolenic acid (ALA), eicosapentaenoic acid, docosahexaenoic acid) and N-6 PUFAs (linoleic acid, gamma-linolenic acid, dihomo-gamma-linolenic acid, arachidonic acid) were determined as percentage total fatty acids. Children's anthropometry was measured annually for a median of 30 months. We used mixed-effects models with restricted cubic splines to construct population body mass index-for-age z-score (BAZ) growth curves for age- and sex-specific quartiles of each PUFA. RESULTS: N-3 ALA was inversely related to BAZ gain after adjustment for sex, baseline age and weight status, as well as household socioeconomic level. Estimated BAZ change between 6 and 14 years among children in the highest quartile of ALA compared with those in the lowest quartile was 0.45 (95% confidence interval: 0.07, 0.83) lower (P-trend=0.006). CONCLUSIONS: N-3 ALA may be protective against weight gain in school-age children. Whether improvement in PUFA status reduces adiposity in pediatric populations deserves evaluation in randomized trials.

Iron status and linear growth: a prospective study in school-age children.

BACKGROUND: Studies regarding the role of iron on linear growth have yielded heterogeneous results. Some trials indicate that iron supplementation of iron-replete infants leads to slower-length gain. However, little is known of the relation between iron status and linear growth in school-age children. METHODS: We quantified plasma ferritin, mean corpuscular volume (MCV), and hemoglobin in 2714 children aged 5-12 years at recruitment into a cohort study. Height was measured periodically for a median of 30 months. Height-for-age Z-scores (HAZ) were calculated using the World Health Organization growth reference. Mixed effects models with restricted cubic splines were used to construct population HAZ-for-age growth curves for sex- and age-specific quartiles of each iron status indicator. RESULTS: Ferritin and MCV were each inversely related to attained HAZ among boys after the adjustment for baseline age, baseline body mass index-for-age Z-score and socioeconomic status. There was a decreasing monotonic relation between quartiles of ferritin and estimated change in HAZ from ages 6 to 14 years (P trend=0.001); boys in the 4th quartile experienced a HAZ change that was 0.46 Z lower than that of boys in the 1st quartile (P=0.0006). Similarly, we observed smaller HAZ change among boys in the highest quartile of MCV in comparison with those in the 1st quartile (P trend=0.001). Hemoglobin was not related to linear growth in boys. None of the iron-status indicators were associated with linear growth in girls. CONCLUSIONS: Higher iron status, as indicated by ferritin and MCV, is related to slower linear growth in iron-replete school-age boys.

Chronic inflammation is associated with overweight in Colombian school children.

BACKGROUND AND AIMS: To examine the cross-sectional associations of inflammatory markers in plasma including C-reactive protein (CRP) and ferritin, and white blood cell (WBC) count, with overweight, skinfold sum (subscapular + triceps), and skinfold ratio (subscapular/triceps) among children from Bogotá, Colombia. METHODS AND RESULTS: The sample (n = 2614) represented low- and middle-income children, aged 5-12 years, from Bogotá. We assessed their anthropometry, sociodemographic characteristics, and circulating inflammatory markers. We defined overweight, including obesity, according to the International Obesity Task Force BMI criteria. After adjustment for potential confounders, children in the fourth quartile of the CRP distribution had a 37% higher prevalence of overweight compared to those in the first quartile (P for trend = 0.03); and children in the fourth quartile of ferritin had a 67% greater prevalence of overweight compared to children in the first quartile (P for trend <0.001). Children in the highest 3 quartiles of the WBC distribution had a 35% higher prevalence of overweight than those in the first quartile (P = 0.03). Ferritin was significantly and positively associated with skinfold sum (P for trend < 0.001), while WBC was significantly and positively associated with skinfold ratio (P for trend < 0.001). There was a significant interaction between CRP and ferritin; children in the highest quartiles of CRP and ferritin had twice the prevalence of overweight compared to those below the highest quartiles (P = 0.001). CONCLUSION: Biomarkers of chronic inflammation are positively associated with child overweight. WBC is positively related to skinfold ratio, a proxy for truncal adiposity.

First Report of Stewart's Wilt of Maize in Argentina Caused by Pantoea stewartii.

Stewart's wilt is a serious disease of corn (Zea mays L.) caused by the bacterium Pantoea stewartii subsp. stewartii (Pss). Typical symptoms of infected fields and dent corn are longitudinal streaks with irregular or wavy margins, which are parallel to the veins and may extend the length of the leaf. These pale to green yellow lesions become dry and brown as the disease progresses producing a leaf blight (4). During the growing seasons 2010 to 2011 and 2011 to 2012, symptoms of bacterial leaf blight of corn were observed in central Argentina maize fields, with an incidence of 54% in Córdoba province. To identify the pathogen, leaves from 10 symptomatic maize plants per field were collected from 15 fields covering a representative geographical area. High populations of morphologically uniform bacteria were isolated from leaf tissues by conventional methods using King's medium B agar (2). Ten representative facultatively anaerobic gram-negative, non-fluorescing, non-motile, catalase positive and oxidase negative rod-shaped and yellow-pigmented bacterial isolates were evaluated further. The biochemical profile obtained was: fermentative metabolism, negative indol, acetoin and hydrogen sulfide production, negative gelatin hydrolysis (22°C), positive acid production from D-glucose and lactose, negative gas production from D-glucose, and negative nitrate reduction (1). All the isolates produced a 300-bp band with PCR using the species specific primer pair PST3581/PST3909c (3). The Pss ATCC 8199 and Pseudomonas fluorescens ATCC 13525 strains were used as positive and negative controls for the PCR assays, respectively. The pathogenicity test was performed by stem inoculation of five to ten P2069 YR maize plants (one to two leaf growth stage) grown in growth chamber. Plants were inoculated by syringe with a 107 to 108 cell/ml bacterial suspension and kept in a humid chamber at 25 to 27°C. Plants inoculated with Pss ATCC 8199 or with sterile water were used as positive and negative control treatments, respectively. The development of symptoms similar to those originally found in the field was observed on all the plants inoculated with the different isolates at 7 to 10 days post inoculation. In addition, symptoms on inoculated plants were similar to those observed for the positive control treatment. No symptoms were found on negative controls. Koch's postulates were fulfilled since bacteria isolated from symptomatic tissue had identical characteristics to isolates used to inoculate plants and to the reference Pss strain for biochemical tests and PCR reaction mentioned above. To our knowledge, this is the first report of P. stewartii subsp. stewartii isolated from diseased maize in Argentina. References: (1) J. G. Holt et al. Page 179 in: Bergey's manual of determinative bacteriology. Williams and Wilkins, Baltimore, MD, 1994. (2) OEPP/EPPO. Bulletin OEPP/EPPO Bulletin, 36: 111, 2006. Pantoea stewartii subsp. stewartii diagnostic. (3) A. Wensing et al. Appl. Environ. Microbiol. 76:6248, 2010. (4) D. G. White Page 4 in: Compendium of corn disease. The American Phytopathology Society, 1999.

Hemoglobin concentration is inversely associated with erythrocyte folate concentrations in Colombian school-age children, especially among children with low vitamin B12 status.

BACKGROUND: While the majority of cases of nutritional anemia in developing countries are caused by iron deficiency, other micronutrient deficiencies may also be involved. In Colombia, it was recently reported that 38% of school children were anemic; yet, the rate of iron deficiency was only 3.6%. OBJECTIVE: To determine if micronutrients other than iron were responsible for low hemoglobin concentrations in Colombian school children. METHODS: We examined hemoglobin concentrations in relation to plasma ferritin, vitamin A, vitamin B12, and erythrocyte folate levels in a representative sample of 2812 low- and middle-income children (5-12 years) from Bogotá, Colombia. RESULTS: In multivariate analysis, hemoglobin concentration was positively associated with child's age, mother's age, household's socioeconomic stratum, and family income. Low ferritin was related to 3.6 g/l lower hemoglobin concentration (95% confidence interval=-6.0, -1.3). Unexpectedly, we found an inverse trend in hemoglobin concentration by quartiles of erythrocyte folate; the adjusted hemoglobin concentration difference between the highest and lowest folate quartiles was -6.0 g/l (95% confidence interval=-7.2, -4.9; P for trend <0.0001). This difference was greatest among children with vitamin B12 concentration <148 pmol/l (-11.5 g/l), followed by children with vitamin B12 concentration 148-221 pmol/l (-7.7 g/l), and smallest in children with vitamin B12 concentration >221 pmol/l (-5.7 g/l); P for interaction=0.04. CONCLUSIONS: Hemoglobin concentration is inversely related to erythrocyte folate concentrations in a setting where folate fortification was adopted more than a decade ago. The impact of improving vitamin B12 status on this inverse relationship should be examined.

Environmental and personal correlates of fruit and vegetable consumption in low income, urban Mexican children.

BACKGROUND: Epidemiological evidence suggests that populations with high fruit and vegetable (FV) consumption have a lower risk for childhood obesity, cancer and cardiovascular diseases. There are no studies that address the correlates of FV intake in Mexican children; therefore, the aim of this study was to identify the frequency of FV consumption by children in Mexico City's low income state schools and their personal (preferences, expectancy, knowledge and self-efficacy) and environmental (accessibility and person in charge of cooking at home) correlates. METHODS: A validated questionnaire to assess accessibility, expectancy, self-efficacy, preference and knowledge; and a 2-day dietary recall were used to assess the FV intake and its correlates in 327 children. Statistical analysis included chi-square and stepwise logistic regression. RESULTS: Average consumption of FV was once a day with a higher proportion of girls consuming FV 3 or more times per day (15.2% versus 6.7%; P < 0.01). The environmental factors that influenced a higher consumption of FV were the mother being responsible for cooking at home (P < 0.02) and accessibility to FV (P < 0.01); whereas the personal factors were self-efficacy (P < 0.05) and preference (P < 0.03) to vegetables. CONCLUSION: Correlates of fruit and vegetable consumption in children from Mexico City's State Schools were being female and accessibility to fruits and vegetables. Home and school environments are decisive for the children to increase FV consumption. Creative ways to encourage FV consumption in boys should be explored. These factors should be considered when designing programmes aimed at increasing consumption of fruits and vegetables in children.

Caracterización de un nuevo material para uso como tejido sustituto en radioterapía / Caracteristcs of material new for use with tejido substitute in rediotherapy

Introducción:Dada la necesidad de un material que reiniera las características apropiadas para se utilizado como tejido sustituto en la práctica de la radioterapía, se elaboró un material con base en tejido blando de pescado, agua y glicerina. Objetivos:Describir la caracterización dosimétrica y química para determinar la viabilidad de la utilización como maniquí o bolus. Matriales, métodos y resultados: eL material, no es degradable por la radiaación, es reciclable y además tiene una composición elemental muy cercana a la ideal. Debido a que su origen es un tejido animal, se encontraron proporciones relativamente altas de silicio y calcio que podrían disminuirse. El análisis dosimétrico se realizó con radiación gamma (Co-60) y rayos de alta energ1a (6MV) midiendo los coeficientyes de atenuación lineal y los porcentajes de dosis en profundidad. En los coeficientes de atenuación lineal se encontró una relación con respecto al agua de 0,990, para Co-60 y de 0,987 para 6MV. Conclusiones: la densidad electrónica y la dosis en profundidad, de acuerdo con los resultados obtenidos, presentan ventajas respecto a otros materiales utilizados convencionalmente.