Bootstrap parametric GB2 and bootstrap nonparametric distributions for studying shiga toxin-producing Escherichia coli strains growth rate variability.

Shiga toxin-producing Escherichia coli (VTEC) strains, including the serotype O157:H7, are considered foodborne pathogens. Transmission occurs through consumption of undercooked meat, unpasteurized dairy products, vegetables, or contaminated water. The variability of pathogenic and nonpathogenic E. coli strains growth parameters at different temperatures and in different media was studied. Bootstrap parametric (Generalized Beta of the Second Kind, GB2) or nonparametric models were used. GB2 estimations show increased growth rates and shortened lag times with increased temperature, as expected. Similar estimations were obtained using the nonparametric model. Parametric and nonparametric growth rate confidence intervals were wider with increased temperature; lag times confidence intervals were wider with decreased temperature. The nonparametric method gives similar confidence intervals to the parametric method, confirming its suitability for growth parameters estimation. The estimations obtained from nonpathogenic E. coli strains approximate distributions from pathogenic E. coli strains.

Different displacement of bioimpedance vector due to Ag/AgCl electrode effect.

BACKGROUND/OBJECTIVES: Bioelectrical impedance vector analysis (BIVA) is increasingly used in clinical research to assess soft tissue hydration. It is known that physical characteristics of electrodes, such as low intrinsic impedance, low electrode/skin contact impedance and type of gel, affect the reliability of noninvasive bioimpedance assessments. The aim of this study was to determine the effect of intrinsic impedance of electrode on the bioimpedance vector displacement in RXc graph. SUBJECTS/METHODS: The intrinsic impedance is measured in nine pregelled disposable Ag/AgCl electrodes usually used for bioimpedance measures. The BIVA method is performed on 35 healthy volunteers using a 50 kHz phase-sensitive bioimpedance analyzer (BIA 101 Anniversary) with the lowest intrinsic impedance electrode and highest. The individual bioimpedance vector is plotted on the bivariate normal interval of reference population. The differences in the mean bioimpedance vectors obtained with each electrode are plotted, with their 95% confidence ellipses, on the dRXc graph. The paired one-sample Hotelling's T2-test is used to compare the differences of the mean bioimpedance vectors. RESULTS: We found large variability in intrinsic resistance (11-665 Ω) and reactance (0.25-2.5 Ω) values of the electrodes analyzed and significant displacement (P<0.05) of bioimpedance vector positions in healthy adults according to the paired one-sample Hotelling's T2-test. CONCLUSIONS: A robust study of all physical characteristics of commercial Ag/AgCl electrodes is necessary to reach consensus on pregelled Ag/AgCl electrodes valid for bioimpedance measurement. This information will enable BIVA users to avoid systemic errors when performing BIVA assessments, specifically when these measurements are used for clinical interpretations.

Body composition analysis in older adults with dementia. Anthropometry and bioelectrical impedance analysis: a critical review.

In clinical practice, geriatric nutritional assessment usually includes nutritional screening, a simple anthropometric assessment, measurement of various biochemical parameters, such as serum albumin, and sometimes (not always) body composition analysis (BCA). However, there is a high prevalence of undiagnosed malnutrition in patients with dementia. Several factors contribute to this situation; probably, the most notable is the methodology used to assess body composition (BC). In this regard, for BCA, techniques are needed that are noninvasive, affordable, safe, simple and that require the minimum possible collaboration by the elderly patient. Consequently, body mass index (BMI) and waist circumference (WC) are widely used as indicators of overall and central adiposity, respectively; however, there is no consensus on the cutoffs for the elderly, and changes in BC (especially muscle-mass depletion) are masked by normal values of BMI and WC. Bioimpedance analysis is a simple, cost-effective and precise method for BCA, provided that cross-validated equations are used. Its main disadvantage is that it is highly sensitive to changes in body water (overhydration or dehydration), leading to substantial errors in BC estimates. However, using Bioelectrical Impedance Vector Analysis errors are minimized, as there is no need for the subject to be normally hydrated and it does not require the use of predictive models.

[Presence of malnutrition and risk of malnutrition in institutionalized elderly with dementia according to the type and deterioration stage]. / Presencia de malnutrición y riesgo de malnutrición en ancianos institucionalizados con demencia en función del tipo y estadío evolutivo.

OBJECTIVE: To determine if there exist differences in the nutritional status of patients with dementia according to the type and severity of the disease. METHOD: In this cross-sectional study we carried out an assessment of the nutritional status (anthropometrical assessment, Mini Nutritional Assessment, Chang's protocol) in 83 institutionalized elderly diagnosed with dementia at evolutionary states of 5, 6, and 7 of GDS (Global Deterioration Scale) and FAST (Functional Assessment Stating). The results were analyzed by the Chi-squared, ANOVA, or Kruskal-Wallis tests, the Scheffé's posteriori contrasts, and the linear trend test. Significance was considered at p < 0.05. RESULTS: The mean age of the patients was 81.22 years. The BMI revealed that 21% of the sample were at risk for malnourishment and 14.5% were malnourished. However, by using the MNA, 56.6% of the patients were at risk for malnourishment and 41% were malnourished. According to the Chang's method, the percentage of malnourished patients was increased to 75.9%. None of these variables showed an association with the type of dementia. A significant association was observed between the evolutionary state of dementia and the BMI (p = 0.004), MNA (p = 0.002 and p = 0.006 for the score and the category, respectively), the muscle circumference of the arm (p = 0.043) and the calf circumference (p = 0.043) but not with the percentage of fat mass nor the nutritional diagnosis established by the Chang's method (degree and type of MN). The linear trend test confirmed that both the MNA and BMI scores and the muscle circumference of the arm and the calf circumference were lower in the more severe dementia states. CONCLUSION: Irrespective of the type of dementia, the presence of malnourishment in institutionalized elderly increases in parallel to the evolutionary degree of the dementia.

[Nutrition and bone health in children]. / Nutrición infantil y salud ósea.

Adequate nutrient intake is an important component of maintaining bone health, and should be encouraged in all age groups. Osteoporosis is a disease in which the density and quality of bone are reduced, leading to weakness of the skeleton and increased risk of fracture, particularly of the spine and hip. Osteoporosis is a global public health problem which currently affects a great proportion of women and men, and is increasing in significance as the population of the world both grows in size and lives longer. Bone loss does not have any symptoms, and often the first sign of having osteoporosis is a fracture. Studies in children and adolescents have shown that calcium and Vitamin D supplements seems to enhance the rate of bone mineral acquisition, and can play a role in osteoporosis prevention. In this paper we review some of the more important questions about this condition, its pathogenesis, diagnosis, and prevention.

Nutrición infantil y salud ósea / Nutrition and bone health in children

Mantener un adecuado estado nutricional en todas las etapas de la vida es decisivo para lograr un metabolismo óseo que favorezca la salud. La osteoporosis se caracteriza por una alteración en la cantidad y calidad de la mineralización ósea, lo que origina una fragilidad del esqueleto con riesgo aumentado de fracturas, especialmente vertebrales y de cadera. Es un problema público a nivel mundial, que afecta a una proporción elevada de hombres y mujeres, y que se desarrolla de forma asintomática hasta que se manifiesta de forma imprevista y causa una fractura del esqueleto. Estudios en niños han demostrado que el desarrollo de osteoporosis en la edad adulta puede verse condicionada por el estado nutricional durante la infancia, especialmente en lo referente a los aportes de calcio y vitamina D. No obstante, existen aún muchas cuestiones abiertas, tanto en lo referente a su patogenia y diagnóstico como a su tratamiento; algunas de éstas se revisan en este trabajo (AU)

Adequate nutrient intake is an important component of maintaining bone health, and should be encouraged in all age groups. Osteoporosis is a disease in which the density and quality of bone are reduced, leading to weakness of the skeleton and increased risk of fracture, particularly of the spine and hip. Osteoporosis is a global public health problem which currently affects a great proportion of women and men, and is increasing in significance as the population of the world both grows in size and lives longer. Bone loss does not have any symptoms, and often the first sign of having osteoporosis is a fracture. Studies in children and adolescents have shown that calcium and Vitamin D supplements seems to enhance the rate of bone mineral acquisition, and can play a role in osteoporosis prevention. In this paper we review some of the more important questions about this condition, its pathogenesis, diagnosis, and prevention (AU)

Gasto energetic y obesidad / Energy output and obesity

Se efectúa un trabajo de revisión sobre el gasto energético, sus componentes y métodos de valoración del mismo, centrado en la aplicación de todos estos conceptos sobre la obesidad infantil y la juvenil. La parte teórica inicial del trabajo está orientada a la comprensión adecuada del estudio efectuado en una población de 70 niños y adolescentes obesos que se describe en una segunda parte. El gasto calórico en reposo (GER) fue determinado por calorimetría indirecta y por las ecuaciones clásicas de estimación del gasto, generando el dato del gasto energético total (GET), tras determinar el factor de actividad física (FA). Se analizan de forma combinada los datos relativos a la ingesta calórica, mediante encuesta de tres días no consecutivos incluyendo un festivo y los datos del cociente respiratorio (CI) y la oxidación de sustratos (AU)

We present and energy expenditure review, its components and mechanism of evaluation focused on infantile and juvenile obesity. The initial theorical part is oriented to the correct comprehension of the study made in an population of obese children and adolescents (range 8-18 years) that we describe in the second part. Initial nutritional assessment included anthropometrics and bioimpedance. The resting energy expenditure (REE) was measured by indirect calorimetry and by the classics equations’ for the estimation of energy expenditure, giving rise to the total energy expenditure value (TEE) taking into account the physical activity (PA). We perform a multivariate analysis of the caloric intake estimated by, a three non consecutive day including a holiday, intake surveys the respiratory quotient (RQ) and the substrate oxidation (AU)