RESUMO
BACKGROUND: The medical body composition analyzer (mBCA) incorporates advances in multifrequency technology and has been validated using a 4-compartment (4C) model in adults but not in youths aged <18 y. OBJECTIVES: This study aimed to formulate a 4C model based on 3 reference methods and develop and validate a body composition prediction equation for the mBCA in youths aged 10â17 y. METHODS: The body density of 60 female and male youths was measured by air displacement plethysmography, total body water by deuterium oxide dilution, and BMC by DXA. Data from the equation group (n = 30) were used to formulate a 4C model. The all-possible-regressions method was used to select variables. The model was validated in a second cohort (n = 30) in a random split design. The accuracy, precision, and potential bias were evaluated by the Bland and Altman procedure. RESULTS: Mean age, weight (W), height (H), waist circumference, and z-score of BMI were 13.6 ± 2.3 y, 54.5 ± 15.5 kg, 156 ± 11.9 cm, 75.5 ± 10.9 cm, and 0.70 ± 1.32 z, respectively. The prediction equation was as follows: FFM in kg (FFMkg) = ([0.2081] ∗ [W] + [0.8814] ∗ [H2cm/RΩ] + [0.2055 ∗ XcΩ])-15.343; R2 = 0.96; standardized root-mean-square error (SRMSE) = 2.18 kg. FFM did not differ between the 4C method (38.9 ± 12.0 kg) and the mBCA (38.4 ± 11.4 kg) (P > 0.05). The relationship between these 2 variables did not deviate from the identity line, was not significantly different from 0, and the slope was not significantly different from 1.0. In the precision prediction model of mBCA, the R2 value was 0.98 and SRMSE was 2.1. No significant bias was found when regressing differences between methods and their means (P = 0.08). CONCLUSIONS: The equation for the mBCA was accurate, precise, had no significant bias, had substantial strength of agreement and could be used in this age group when subjects were preferentially within the constraints of a specified body size.
Assuntos
Tecido Adiposo , Composição Corporal , Adulto , Humanos , Masculino , Feminino , Adolescente , Óxido de Deutério/metabolismo , Tecido Adiposo/metabolismo , Pletismografia , Impedância Elétrica , Absorciometria de Fóton , Reprodutibilidade dos Testes , Água CorporalRESUMO
Se presenta conceptos del saber hacer investigación científica asociada a la calidad de las mediciones, y dentro de ella sobre la calidad intrínseca de la medición de variables, dirigida a dos condiciones de la misma: la precisión y exactitud. Se describe formas de evaluación de la precisión como ser el coeficiente de variación y el error técnico de las mediciones. Por otro lado se describe formas de evaluación de la exactitud como son la regresión linear y el puntaje Z. También se sugieren y se describen las acciones y las herramientas para mejorar tanto la precisión como la exactitud. El análisis de agua enriquecida con oxido de deuterio, es una temática que fue tomada en cuenta por la Agencia Internacional de Energía Atómica (IAEA), Viena, Austria, en la gestión 2021, y se organizó una actividad mediante el "Estudio de Interlaboratorios, Oxido de Deuterio por FTIR 2021". El propósito fue asegurar la calidad integral en la capacidad construida en el uso de técnicas de isotopos estables para la evaluación del estado de salud y nutricional. Así mismo, evaluar la calidad de medición de la exactitud relativa sobre el enriquecimiento del agua con óxido de deuterio en 43 laboratorios a nivel internacional, grupo en cual se incluyó al Laboratorio de Biología Atómica (LABA) de la Unidad de Crecimiento y Desarrollo (UCREDE). Se utilizó la regresión linear y el puntaje Z para evaluar la exactitud. Se concluye que los resultados demostraron un muy buen rendimiento en exactitud relativa con los equipos FTIR que midieron el enriquecimiento de deuterio en muestras de agua.
Concepts of knowing how to do scientific research associated with the quality of measurements are presented, and within it on the intrinsic quality of the measurement of variables, aimed at two conditions of the same: precision and accuracy. Forms of precision evaluation are described, such as the coefficient of variation and the technical error of the measurements. On the other hand, forms of accuracy evaluation are described, such as linear regression and Z-score. Actions and tools to improve both precision and accuracy are also suggested and described. The analysis of water enriched with deuterium oxide is a topic that was taken into account by the International Atomic Energy Agency (IAEA), Vienna, Austria, in the 2021 management, and an activity was organized through the Interlaboratory Study, Deuterium Oxide by FTIR 2021. The purpose was to ensure comprehensive quality in the capacity built in the use of stable isotope techniques for the evaluation of health and nutritional status. Likewise, to evaluate the quality of measurement of the relative accuracy of the enrichment of water with deuterium oxide in 43 laboratories at the international level, a group that included the Atomic Biology Laboratory (LABA) of the Growth and Development Unit (UCREDE ). Linear regression and Z-score were used to assess accuracy. It is concluded that the results demonstrated a very good performance in relative accuracy with the FTIR equipment that measured deuterium enrichment in water samples.
Assuntos
Água , Óxido de Deutério , Pesquisa , Estado Nutricional , AltitudeRESUMO
The evaluation of body composition (BC) is relevant in the evaluation of children's health-disease states. Different methods and devices are used to estimate BC. The availability of methods and the clinical condition of the patient usually defines the ideal approach to be used. In this cross-sectional study, we evaluate the accuracy of different methods to estimate BC in Mexican children and adolescents, using the 4-C model as the reference. In a sample of 288 Mexican children and adolescents, 4-C body composition assessment, skinfold-thickness (SF), dual-energy X-ray absorptiometry (DXA), air displacement plethysmography (ADP), and deuterium dilution (D2O) were performed, along with MRI in a subsample (52 participants). The analysis of validity was performed by correlation analysis, linear regression, and the Bland-Altman method. All methods analyzed showed strong correlations for FM with 4-C values and between each other; however, DXA and MRI overestimated FM, whereas skinfolds and ADP under-estimated FM. Conclusion: The clinical assessment of BC by means of SF, ADP, DXA, MRI and D2O correlated well with the 4-C model and between them, providing evidence of their clinical validity and utility. The results from different methods are not interchangeable. Preference between methods may depend on their availability and the specific clinical setting.
Assuntos
Composição Corporal , Pletismografia , Absorciometria de Fóton/métodos , Adolescente , Criança , Estudos Transversais , Óxido de Deutério , Humanos , Imageamento por Ressonância Magnética , Pletismografia/métodosRESUMO
Thirty-six Nellore steers at 20 months of age on average and initial body weight of 360 kg, fed ad libitum for 78 days and two levels of feed restriction for 58 days and posterior ad libitum feeding for 78 days were used to estimate body composition using the methods of indirect deuterium oxide or the 9th-10th-11thribs cut. The body water content was calculated with equations established for Nellore steers. The chemical body composition was different for the ether extract content. The animals subjected to feed restriction presented higher body fat content when estimated by deuterium than by the rib cut. The deuterium oxide or 9th-10th-11thribs cut methods used for body composition determination were effective to estimate body contents for animals fed ad libitum, however, not for animals on feed restriction. Comparatively, the indirect method of deuterium oxide was better than the 9th-10th-11thribs cut method to estimate body composition in Nellore steers submitted to feed restriction; however, both methods were similar in animals fed ad libitum.(AU)
Assuntos
Animais , Bovinos , Restrição Calórica/métodos , Restrição Calórica/veterinária , Composição Corporal , Peso Corporal , Água Corporal , Costelas , Óxido de DeutérioRESUMO
Leishmania are sandfly-transmitted protists that induce granulomatous lesions in their mammalian host. Although infected host cells in these tissues can exist in different activation states, the extent to which intracellular parasites stages also exist in different growth or physiological states remains poorly defined. Here, we have mapped the spatial distribution of metabolically quiescent and active subpopulations of Leishmania mexicana in dermal granulomas in susceptible BALB/c mice, using in vivo heavy water labeling and ultra high-resolution imaging mass spectrometry. Quantitation of the rate of turnover of parasite and host-specific lipids at high spatial resolution, suggested that the granuloma core comprised mixed populations of metabolically active and quiescent parasites. Unexpectedly, a significant population of metabolically quiescent parasites was also identified in the surrounding collagen-rich, dermal mesothelium. Mesothelium-like tissues harboring quiescent parasites progressively replaced macrophage-rich granuloma tissues following treatment with the first-line drug, miltefosine. In contrast to the granulomatous tissue, neither the mesothelium nor newly deposited tissue sequestered miltefosine. These studies suggest that the presence of quiescent parasites in acute granulomatous tissues, together with the lack of miltefosine accumulation in cured lesion tissue, may contribute to drug failure and nonsterile cure.IMPORTANCE Many microbial pathogens switch between different growth and physiological states in vivo in order to adapt to local nutrient levels and host microbicidal responses. Heterogeneity in microbial growth and metabolism may also contribute to nongenetic mechanisms of drug resistance and drug failure. In this study, we have developed a new approach for measuring spatial heterogeneity in microbial metabolism in vivo using a combination of heavy water (2H2O) labeling and imaging mass spectrometry. Using this approach, we show that lesions contain a patchwork of metabolically distinct parasite populations, while the underlying dermal tissues contain a large population of metabolically quiescent parasites. Quiescent parasites also dominate drug-depleted tissues in healed animals, providing an explanation for failure of some first line drugs to completely eradicate parasites. This approach is broadly applicable to study the metabolic and growth dynamics in other host-pathogen interactions.
Assuntos
Óxido de Deutério , Granuloma/parasitologia , Interações Hospedeiro-Parasita , Processamento de Imagem Assistida por Computador/métodos , Leishmania mexicana/metabolismo , Leishmaniose Cutânea/parasitologia , Espectrometria de Massas/métodos , Pele/patologia , Animais , Modelos Animais de Doenças , Feminino , Marcação por Isótopo , Leishmaniose Cutânea/patologia , Macrófagos/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Músculos/parasitologia , Músculos/patologia , Pele/parasitologiaRESUMO
It is possible to gain a deeper insight into the role of water in biology by using physicochemical variant molecules, such as deuterium oxide (D2 O); however, D2 O is toxic to multicellular organisms in high concentrations. By using a unique desiccation-rehydration process, we demonstrate that the anhydrobiotic nematode Panagrolaimus superbus is able to tolerate and proliferate in 99 % D2 O. Moreover, we analysed P. superbus' water-channel protein (aquaporin; AQP), which is associated with dehydration/rehydration, by comparing its primary structure and modelling its tertiary structure in silico. Our data evidence that P. superbus' AQP is an aquaglyceroporin, a class of water channel known to display a wider pore; this helps to explain the rapid and successful organismal influx of D2 O into this species. This is the first demonstration of an animal able to withstand high D2 O levels, thus paving a way for the investigation of the effects D2 O on higher levels of biological organization.
Assuntos
Óxido de Deutério/metabolismo , Nematoides/metabolismo , Sequência de Aminoácidos , Animais , Aquaporinas/química , Aquaporinas/metabolismo , Proteínas de Helminto/química , Proteínas de Helminto/metabolismo , Humanos , Nematoides/crescimento & desenvolvimento , Estrutura Terciária de Proteína , Alinhamento de SequênciaRESUMO
OBJECTIVE: To explore changes in the nutritional status of pediatric cancer patients before and after chemotherapy and evaluate the correlation between deuterium oxide dilution, bioelectric impedance analysis, and anthropometry for assessment of body composition. METHODS: This study included 14 children (aged 5.6 to 13.6 years) and classified them as having hematologic or solid tumors. They had their body composition analyzed according to deuterium oxide, bioelectric impedance, and anthropometric measurements before the first chemotherapy cycle and after three and six months of therapy. RESULTS: The patients in the hematologic tumor group had an increase in weight, height, body mass index, waist, hip, and arm circumference, subscapular skinfold thickness, and fat mass with the isotope dilution technique during chemotherapy. In the solid tumor group, the children showed a reduction in fat-free mass when assessed by bioimpedance analysis. We found a positive correlation between the triceps skinfold thickness and fat mass determined by bioimpedance analysis and deuterium oxide. The arm muscle circumference correlated with the fat-free mass estimated by bioimpedance analysis and deuterium oxide. CONCLUSIONS: Patients with hematologic tumors had an increase in body weight, height, and fat mass, which was not identified in the solid tumor group. The positive correlation between anthropometry (triceps skinfold thickness and arm muscle circumference), deuterium oxide dilution, and bioelectric impedance analysis shows the applicability of anthropometry in clinical practice.
Assuntos
Antropometria/métodos , Óxido de Deutério/metabolismo , Impedância Elétrica , Estado Nutricional , Adolescente , Composição Corporal , Criança , Pré-Escolar , Óxido de Deutério/administração & dosagem , Feminino , Humanos , Masculino , Neoplasias/fisiopatologiaRESUMO
Thirty-six Nellore steers at 20 months of age on average and initial body weight of 360 kg, fed ad libitum for 78 days and two levels of feed restriction for 58 days and posterior ad libitum feeding for 78 days were used to estimate body composition using the methods of indirect deuterium oxide or the 9th-10th-11thribs cut. The body water content was calculated with equations established for Nellore steers. The chemical body composition was different for the ether extract content. The animals subjected to feed restriction presented higher body fat content when estimated by deuterium than by the rib cut. The deuterium oxide or 9th-10th-11thribs cut methods used for body composition determination were effective to estimate body contents for animals fed ad libitum, however, not for animals on feed restriction. Comparatively, the indirect method of deuterium oxide was better than the 9th-10th-11thribs cut method to estimate body composition in Nellore steers submitted to feed restriction; however, both methods were similar in animals fed ad libitum.
Assuntos
Animais , Bovinos , Composição Corporal , Peso Corporal , Restrição Calórica/métodos , Restrição Calórica/veterinária , Água Corporal , Costelas , Óxido de DeutérioRESUMO
ABSTRACT Objective: To explore changes in the nutritional status of pediatric cancer patients before and after chemotherapy and evaluate the correlation between deuterium oxide dilution, bioelectric impedance analysis, and anthropometry for assessment of body composition. Methods: This study included 14 children (aged 5.6 to 13.6 years) and classified them as having hematologic or solid tumors. They had their body composition analyzed according to deuterium oxide, bioelectric impedance, and anthropometric measurements before the first chemotherapy cycle and after three and six months of therapy. Results: The patients in the hematologic tumor group had an increase in weight, height, body mass index, waist, hip, and arm circumference, subscapular skinfold thickness, and fat mass with the isotope dilution technique during chemotherapy. In the solid tumor group, the children showed a reduction in fat-free mass when assessed by bioimpedance analysis. We found a positive correlation between the triceps skinfold thickness and fat mass determined by bioimpedance analysis and deuterium oxide. The arm muscle circumference correlated with the fat-free mass estimated by bioimpedance analysis and deuterium oxide. Conclusions: Patients with hematologic tumors had an increase in body weight, height, and fat mass, which was not identified in the solid tumor group. The positive correlation between anthropometry (triceps skinfold thickness and arm muscle circumference), deuterium oxide dilution, and bioelectric impedance analysis shows the applicability of anthropometry in clinical practice.
RESUMO Objetivo: Verificar mudanças no estado nutricional de crianças com câncer antes e após o tratamento quimioterápico e avaliar a correlação entre diluição de óxido de deutério, análise de impedância bioelétrica (BIA) e dados antropométricos. Métodos: Quatorze crianças (entre 5,6 e 13,6 anos de idade) foram incluídas e classificadas como tendo tumores hematológicos ou sólidos. A composição corporal foi medida pelo óxido de deutério, impedância bioelétrica e medidas antropométricas antes da primeira quimioterapia e após três e seis meses de terapia. Resultados: Os pacientes do grupo de tumores hematológicos aumentaram o peso, a estatura, o índice de massa corporal, a circunferência da cintura, quadril e braço, dobra cutânea subescapular e a massa gorda com a técnica de diluição isotópica durante o tratamento quimioterápico. No grupo de tumores sólidos, as crianças mostraram uma redução na massa magra quando avaliadas por análise de impedância. Houve uma correlação positiva entre a dobra cutânea tricipital e a massa gorda determinadas pela análise de impedância e pelo óxido de deutério. A circunferência muscular do braço correlacionou-se com a massa magra estimada pela análise de impedância e pelo óxido de deutério. Conclusões: Pacientes com tumores hematológicos tiveram aumento no peso corporal, estatura e massa gorda, o que não foi observado naqueles com tumores sólidos. A boa correlação entre a antropometria (dobra cutânea tricipital e circunferência muscular do braço), a diluição do óxido de deutério e a análise da impedância bioelétrica mostra a aplicabilidade da antropometria na prática clínica.
Assuntos
Humanos , Masculino , Feminino , Pré-Escolar , Criança , Adolescente , Antropometria/métodos , Estado Nutricional , Impedância Elétrica , Óxido de Deutério/metabolismo , Composição Corporal , Óxido de Deutério/administração & dosagem , Neoplasias/fisiopatologiaRESUMO
The aim of this study was determine the energy and protein requirements for maintenance and gain of Nellore steers. Thirty six Nellore steers with an average weight and age of 359±13 kg and 20 months at the beginning of the trial were individually fed for 56. The steers were fed the same diet (76.43% TDN and 13.62% CP) in three levels of dry matter (DM) intake, ad libitum, 75 g DM/kg BW0.75 and 60 g DM/kg BW0.75. The initial and final body composition was estimated with the marker deuterium oxide that allowed repeated water estimate in the same animal. Deuterium in blood samples was analyzed by mass spectrometry. The effects of intake levels, comparison of intercept and slope among feeding level, and equations were evaluated by the analysis of variance, adopting P<0.05 as a significant level. The net energy for maintenance was 75 kcal/kg EBW 0.75 or 70 kcal/kg BW 0.75. The net energy for gain for steers with 350 to 450 kg weight was 5.1 to 6.1Mcal. The efficiency of energy utilization for maintenance, km, was 0.7492 and for weight gain, kg, was 0.3404. The metabolizable protein requirement for maintenance was 4.32 * BW0.75and the net protein for gain was estimated with the equation NPg= (254.68*EBWG) (29.38*RE). The technique of deuterium oxide marker used to estimate energy and protein requirement for maintenance and weight gain at Nellore steers confirm the hypothesis presented in NRC, that NEmis lower than the requirement for taurine cattle. On the other hand, the reverse was true for the NP requirement for maintenance and for weight gain. We consider that indirect method using D2O for estimate body composition in zebu cattle was suitable to determine nutrient requirements.(AU)
Assuntos
Animais , Bovinos , Aumento de Peso , Composição Corporal , Crescimento e Desenvolvimento , Óxido de Deutério/análise , Necessidades Nutricionais , BiomarcadoresRESUMO
The aim of this study was determine the energy and protein requirements for maintenance and gain of Nellore steers. Thirty six Nellore steers with an average weight and age of 359±13 kg and 20 months at the beginning of the trial were individually fed for 56. The steers were fed the same diet (76.43% TDN and 13.62% CP) in three levels of dry matter (DM) intake, ad libitum, 75 g DM/kg BW0.75 and 60 g DM/kg BW0.75. The initial and final body composition was estimated with the marker deuterium oxide that allowed repeated water estimate in the same animal. Deuterium in blood samples was analyzed by mass spectrometry. The effects of intake levels, comparison of intercept and slope among feeding level, and equations were evaluated by the analysis of variance, adopting P<0.05 as a significant level. The net energy for maintenance was 75 kcal/kg EBW 0.75 or 70 kcal/kg BW 0.75. The net energy for gain for steers with 350 to 450 kg weight was 5.1 to 6.1Mcal. The efficiency of energy utilization for maintenance, km, was 0.7492 and for weight gain, kg, was 0.3404. The metabolizable protein requirement for maintenance was 4.32 * BW0.75and the net protein for gain was estimated with the equation NPg= (254.68*EBWG) (29.38*RE). The technique of deuterium oxide marker used to estimate energy and protein requirement for maintenance and weight gain at Nellore steers confirm the hypothesis presented in NRC, that NEmis lower than the requirement for taurine cattle. On the other hand, the reverse was true for the NP requirement for maintenance and for weight gain. We consider that indirect method using D2O for estimate body composition in zebu cattle was suitable to determine nutrient requirements.
Assuntos
Animais , Bovinos , Aumento de Peso , Composição Corporal , Crescimento e Desenvolvimento , Necessidades Nutricionais , Óxido de Deutério/análise , BiomarcadoresRESUMO
An objective method of assessing breastfeeding practices is required to evaluate progress toward the World Health Organization Global Target 2025: to increase exclusive breastfeeding (EBF) rates in the first 6 months to at least 50% by 2025. Currently, assessment of EBF at the population level is based on mother or caregiver reporting, which risks recall and social desirability bias. A more objective method is the deuterium oxide dose to mother (DTM) technique, in which lactating mothers are given a small amount of deuterium-labeled water. The infant receives deuterium during breastfeeding, and a compartmental model is used to determine the amount of human milk consumed by the infant, and the exclusivity of breastfeeding practices. If the amount of human milk consumed by an infant is determined using the DTM technique and the concentration of nutritional components or potentially toxic contaminants is measured, then the infant's intake of essential nutrients or environmental contaminants can be ascertained.
Assuntos
Aleitamento Materno , Óxido de Deutério/farmacocinética , Ingestão de Alimentos , Leite Humano/química , Adulto , África Subsaariana , Ásia , Peso Corporal , Óxido de Deutério/administração & dosagem , Óxido de Deutério/análise , Feminino , Infecções por HIV , Humanos , Lactente , Recém-Nascido , Masculino , México , Micronutrientes/análise , Resíduos de Praguicidas/análise , Saliva/química , Deficiência de Vitamina A/etiologia , Abastecimento de ÁguaRESUMO
OBJECTIVE: To investigate the influence of changes in energy balance and body composition on the rate of weight loss throughout 1 year of Roux-en-Y gastric bypass. METHODS: Variables were collected pre-, 6, and 12 months (M) post-surgery from 18 women (BMI ≥ 40 and ≤ 50 kg m-2, 20 to 45 years). Total energy expenditure (TEEm), fat-free mass (FFM), and fat mass (FM) were measured by doubly labeled water. Self-reported energy intake (EIsr) was obtained from three non-consecutive food diaries. Metabolic adaptation was assessed via deviations from TEE predictive equation, and the calculated energy intake (EIc) via the sum of TEE and change in body stores. RESULTS: BMI significantly decreased (mean ± SD) from 45 ± 2 kg m-2 to 32 ± 3 kg m-2 at 6 M, and to 30 ± 3 kg m-2 at 12 M after surgery. The TEEm reduced significantly at both time points when compared with pre-surgery (6 M: - 612 ± 317 kcal day-1; 12 M: - 447 ± 516 kcal day-1). At 6 M, a metabolic adaptation was observed and the energy balance was - 1151 ± 195 kcal day-1, while at 12 M it was - 332 ± 158 kcal day-1. Changes in the values of TEEm were associated with changes in body weight at 12 M post-surgery. A significant underreporting was observed for EIsr (1057 ± 385 kcal day-1) vs. EIc (2083 ± 309 kcal day-1) at 12 M post-operative. CONCLUSION: The higher rate of weight loss at 6 M post-surgery was a response to energy imbalance, which was caused by high restriction in energy intake even with the presence of metabolic adaptation at this time. The EIsr was not sufficiently accurate to assess the energy consumption of this population. REGISTRATION OF CLINICAL TRIALS (OBSERVATIONAL STUDY): Brazilian Clinical Trials Registry: RBR-8k5jsj. Universal Trial Number: U1111-1206-0858.
Assuntos
Metabolismo Energético/fisiologia , Derivação Gástrica , Redução de Peso/fisiologia , Adulto , Óxido de Deutério , Humanos , Estudos Longitudinais , Pessoa de Meia-Idade , Adulto JovemRESUMO
El objetivo del estudio fue determinar la validez del porcentaje de grasa corporal (% GC) estimado por la ecuación de Slaughter en escolares costarricenses. Participaron 54 niños y 49 niñas con una edad promedio 7.8 ± 1.0 años. El óxido de deuterio (D2O) fue el método de referencia para determinar la masa grasa (FM) expresada como % GC. Se utilizó un análisis de regresión lineal y prueba t para determinar la asociación y las diferencias entre el %GC por la ecuación de Slaughter y D2O. La concordancia entre métodos se determinó por el coeficiente de correlación de concordancia (CCC) de Lin. La medición de acuerdo entre los métodos se analizó mediante el procedimiento de Bland-Altman. El % GC entre métodos fue significativamente diferente en niños (26.3 ± 7.4% vs 22.4 ± 7.0%) y niñas (33.2 ± 5.7% vs 26.1 ± 5.7%). La asociación entre métodos no fue significativa en niños (R2 = 0.76, p <0.0001) y niñas (R2 = 0.24, p <0.0001). Los gráficos de Bland-Altman mostraron que la ecuación de Slaughter subestimó el % GC en 6,0% en niños y 3,5% en niñas, en comparación con D2O. El CCC de Lin identificó una fuerza de concordancia pobre entre métodos, niños ρc= 0.87 y niñas ρc= 0.56. Con los resultados se concluye que la ecuación de Slaughter registró baja concordancia del % GC en comparación con el D2O en escolares costarricenses(AU)
The aim of the study was to determine the validity of the body fat percentage (% GC) estimated by the Slaughter equation in Costa Rican school children. The sample consisted of 54 male and 49 female, mean age 7.8 ± 1.0 years. Deuterium oxide dilution (D2O) was the reference method to determine the fat mass (FM) expressed as BF%. Linear regression analyses and paired sample t-tests were used to test association and mean differences between Slaughter equation and D2O BF%. Concordance between Slaughter equation and D2O BF% was determined by Lin's concordance correlation coefficient (CCC). Measurement of agreement between the two methods was analyzed using the Bland-Altman procedure. Measurements of BF% by Slaughter equation and D2O were significantly different for boys (26.3 ± 7.4% vs 22.4 ± 7.0%) and for girls (33.2 ± 5.7% vs 26.1 ± 5.7%). Non-significant association between methods was found in males (R2 = 0.76, p <0.0001) and females (R2 = 0.24, p <0.0001). Bland-Altman plots showed that Slaughter equation underestimated the %BF in a 6.0% for boys and in a 3.5% for girls compared with D2O. Lin's CCC identified poor strength of concordance between the two methods, for boys ρc= 0.87 and for girls ρc= 0.56. With the results we conclude that the Slaughter equation registered low agreement of BF% compared against the one obtained by D2O in Costa Rican school children(AU)
Assuntos
Humanos , Masculino , Feminino , Criança , Composição Corporal/genética , Óxido de Deutério/metabolismo , Distribuição da Gordura Corporal , Obesidade Infantil , Alimentos, Dieta e NutriçãoRESUMO
Vector-borne diseases have increased pesticide use in urban areas (UA) and agricultural areas (AA) in Mexico. Breast milk can be contaminated by pesticide exposure. The objective of the study was to measure breast milk intake by deuterium oxide dilution as well as organochlorine and pyrethroid transfer from mother to infant in AA and UA of Sonora, Mexico. Human milk intake was determined by the 'dose-to-mother' technique using deuterium oxide (D2O) dilution. Mothers' body composition was also assessed by this technique and the intercept method. Pyrethroids (deltamethrin, cypermethrin and cyhalothrin) and organochlorine pesticide residues (p,p'- DDT, p,p'- DDE, p,p'- DDD) in breast milk samples were measured by gas chromatography. Sixty-two lactating women and their infants participated in the study, 32 lived in the UA and 30 lived in the AA. Breast milk intake was approximately 100 mL higher in the AA than in the UA 799 ± 193 and 707 ± 201 mL/day, respectively (p < 0.05). The concentrations of p,p'- DDT and cypermethrin levels in breast milk were higher in the UA than in the AA (p < 0.05 and p = 0.001, respectively). None of the pyrethroids and organochlorine pesticides studied surpassed the Acceptable Daily Intake (ADI) in milk for humans according to EPA and FAO/WHO. In conclusion, breast milk intake was higher in the AA compared to the UA. The p,p'- DDT and cypermethrin levels in breast milk were higher in the UA compared to the AA. Since pesticide levels in human milk did not exceed the ADI, breastfeeding is still a safe practice and should be encouraged.
Assuntos
Aleitamento Materno/efeitos adversos , Óxido de Deutério/farmacocinética , Leite Humano/química , Praguicidas/análise , Adulto , Agricultura , Cromatografia Gasosa , Feminino , Humanos , Hidrocarbonetos Clorados/análise , Hidrocarbonetos Clorados/farmacocinética , Lactente , México , Mães , Praguicidas/farmacocinética , Piretrinas/análise , Piretrinas/farmacocinética , Adulto JovemRESUMO
BACKGROUND: Several studies have reported increased resting energy expenditure (REE) in human immunodeficiency virus (HIV)-infected patients with HIV-associated lipodystrophy syndrome (HALS). However, limited data exist on the total energy expenditure (TEE). This study was aimed at evaluating the REE and TEE of HIV-infected patients with and without HALS by using the doubly labeled water (DLW) technique and the activity monitor based on accelerometry system (AM), and comparing the results obtained using both methods. METHODS: Evaluated total of 45 HIV+ men undergoing antiretroviral therapy, including 18 LIPO- (without lipodystrophy) and 27 LIPO+ (with lipodystrophy) individuals were evaluated. Habitual physical activity patterns were measured by using the ActivPAL™ AM system, REE by indirect calorimetry, and TEE by DLW and AM. RESULTS: No significant differences were found between LIPO- and LIPO+ in REE (1,433 ± 196 vs. 1,510 ± 203 kcal), TEE-DLW (2,691 ± 856 vs. 2,618 ± 415 kcal) and TEE-AM (2,560 ± 458 vs. 2,594 ± 456 kcal), respectively. RQ was a predictor of REE in LIPO+. TEE estimated by the AM had a moderate correlation with DLW, but there was a wide variance in the intra-subject results. CONCLUSIONS: TEE is not increased in HIV-infected patients with HALS. AM should be used with caution for TEE evaluation during clinical practice.
Assuntos
Antirretrovirais/uso terapêutico , Metabolismo Energético , Síndrome de Lipodistrofia Associada ao HIV/metabolismo , Acelerometria , Adulto , Calorimetria Indireta , Óxido de Deutério , Infecções por HIV/tratamento farmacológico , Infecções por HIV/metabolismo , Síndrome de Lipodistrofia Associada ao HIV/tratamento farmacológico , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Adulto JovemRESUMO
In Mexico, infants (0-2 years old) show the highest prevalence of vitamin A deficiency (VAD), measured by serum retinol concentrations. Thus, we consider that low vitamin A (VA) intake through breast milk (BM) combined with poor weaning practices are the main factors that contribute to VAD in this group. We combined the assessment of VA status in lactating women using BM retinol and a stable isotope 'dose-to-mother' technique to measure BM production in women from urban and agricultural areas. Infants' mean BM intake was 758 ± 185 mL, and no difference was observed between both areas (p = 0.067). Mean BM retinol concentration was 1.09 µmol/L, which was significantly lower for the agricultural area (p = 0.028). Based on BM retinol concentration, 57% of women were VAD; although this prevalence fell to 16% when based on fat content. Regardless of the VA biomarker used here, infants from the urban and agricultural areas cover only 66% and 49% of their dietary adequate intake from BM, respectively (p = 0.054). Our data indicate that VAD is still a public health concern in Mexico. Adopting both methods to assess VA transfer from the mother to the breastfed child offers an innovative approach towards the nutritional assessment of vulnerable groups.
Assuntos
Aleitamento Materno , Dieta , Lactação/metabolismo , Fenômenos Fisiológicos da Nutrição Materna , Leite Humano/química , Deficiência de Vitamina A/etiologia , Vitamina A/administração & dosagem , Adolescente , Adulto , Pré-Escolar , Óxido de Deutério , Feminino , Humanos , Técnicas de Diluição do Indicador , Lactente , México/epidemiologia , Mães , Estado Nutricional , Prevalência , Deficiência de Vitamina A/epidemiologia , Adulto JovemRESUMO
The main aim goal of this review was to gather information about recent publications related to deuterium oxide (D2O), and its use as a scientific tool related to human health. Searches were made in electronic databases Pubmed, Scielo, Lilacs, Medline and Cochrane. Moreover, the following patent databases were consulted: EPO (Espacenet patent search), USPTO (United States Patent and Trademark Office) and Google Patents, which cover researches worldwide related to innovations using D2O.
Assuntos
Pesquisa Biomédica/métodos , Biotecnologia/métodos , Óxido de Deutério , Óxido de Deutério/administração & dosagem , Óxido de Deutério/química , Óxido de Deutério/uso terapêutico , HumanosRESUMO
BACKGROUND/OBJECTIVES: The accuracy of dietary assessment methods has rarely been validated using precise techniques. The objective of this work was to evaluate the validity of energy intake (EI) estimated with food records (FRs) and 24-h recalls (24hRs) against total energy expenditure (EE) estimated by the doubly labeled water (DLW) method. In addition, the magnitude of EI under-reporting was assessed along with its associated characteristics. SUBJECTS/METHODS: The studied group included 83 adults between 20 and 60 years of age who were recruited from a population-based sample. Within-person variation-adjusted means of EI estimated from two FRs and three 24hRs were compared with EE estimated using the DLW method multiple-point protocol. The Wilcoxon signed-rank test was used to assess the differences between EI and EE, whereas Bland-Altman and survival-agreement plots assessed the agreement between the estimates. RESULTS: The mean EE (2540 kcal) was greater than the mean reported EI for both dietary assessment methods (FR: 1774 kcal; 24hR: 1658 kcal, P<0.01). The frequency of under-reporting was lower (20%) for EI estimated with the 24hR than that estimated with the FR (32%). Men presented lower magnitude of under-reported EI than women did. For women, differences between EI and EE were lower with FR than with 24hR. Overall, FR and 24hR showed similar performance. The mean under-reported EI was ~30% for both methods. CONCLUSIONS: Irregular meal habits, smoking and low education were associated with the under-report of EI. Both FR and 24hR are subjected to bias suggesting the need of refining the procedures applied in dietary assessment methods.
Assuntos
Óxido de Deutério/metabolismo , Registros de Dieta , Ingestão de Energia , Metabolismo Energético , Adulto , Viés , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Necessidades Nutricionais , Valor Preditivo dos Testes , Adulto JovemRESUMO
BACKGROUND: Diet is related to the prevention of chronic diseases, but assessing dietary intake is a complex task, especially in socially vulnerable populations. OBJECTIVES: To assess the accuracy of the 24-hour food recall (24HFR) and the food frequency questionnaire (FFQ) methods in socially vulnerable women in Brazil and compare these methods against doubly labeled water (DLW). DESIGN: Cross-sectional study. Energy intake (EI) was measured using 3 24HFRs and 1 FFQ. Total energy expenditure (TEE) was measured using DLW. Cutoff points were calculated to assess underreporting and overreporting using both the difference and the ratio between the EI and TEE. PARTICIPANTS/SETTING: Sixty-seven socially vulnerable, nondieting adult women with stable body weight and mothers of malnourished children. MAIN OUTCOME MEASURES: EI, in kilocalories, derived from 24HFR and FFQ. STATISTICAL ANALYSES: Repeated measures analysis of variance was used to compare EI and TEE and Bland-Altman graphs were plotted to assess the agreement between these variables. Spearman correlation coefficient between the ratio of EI to TEE and socioeconomic or anthropometric variables was calculated. RESULTS: Mean TEE was 2,186 kcal (95% CI 2,063 to 2,309 kcal). EI obtained through 24HFR (mean=1,848.6 kcal [95% CI 1,737.5 to 1,959.7 kcal]) was significantly lower than TEE (P=0.01), and significantly lower than the EI obtained through FFQ (mean=2,084.5 [95% CI 1,929.0 to 2,240.0 kcal]; P<0.01). There were no statistically significant differences between the EI values of FFQ and TEE (P=0.89). The distribution of underreporters, nonunderreporters, and overreporters were more homogenous in the FFQ method. There was a positive correlation between body fat percentage and underreporting in the FFQ method (r=0.245; P=0.046). CONCLUSIONS: The methods of assessing dietary intake in our study showed poor agreement with TEE obtained by DLW. These may, therefore, not be the most suitable methods for assessing EI in this population.