RESUMO
BACKGROUND: Little information is available on the validity of anthropometry or impedance-based equations for prediction of total body water (TBW) in African children. This study was designed to validate and develop equations to predict total body water in Cameroonian children. METHODS: TBW was measured by deuterium dilution in 102 children between 24 and 60 months of age and compared with the ones predicted by 5 anthropometric and 7 BIA equations. Multiple linear regression analysis was used to develop prediction equations for TBW from anthropometric parameters. RESULTS: Unacceptable discrepancies in the estimates of TBW at individual level were noted with all the equations tested. The following new anthropometry and BIA equations for the estimation of TBW were respectively developed: TBW = 6.488 + 0.434 × sex−0.039 × age + 0.670 × weight−0.081 × MUAC (cm)−0.372 × BMI (adjustedR2= 0.71,RMSE = 3.6), and TBW =−6.206 + 0.0037 × height2/Z−0.041 × age + 0.265 × weight + 0.1214 × height (adjustedR2=0.68, RMSE = 1.4). The cross-validation procedures revealed that the predicted values of TBW compared with measured values are accurate at a group level. CONCLUSION: The current published anthropometric and BIA equations are invalid for the estimation of TBW in Cameroonian preschool children. The newly developed anthropometry or BIA prediction equations are valid for use in Cameroonian children aged 2460 months
Assuntos
Humanos , Masculino , Feminino , Pré-Escolar , Antropometria/métodos , Água Corporal/química , Deutério/análise , Deutério/farmacocinética , Impedância ElétricaRESUMO
AIM: To compare the uptake of 11C-deuterodeprenyl (11C-DED) and 11C-methionine (11C-MET) in three human glioma cell lines and study the relationship with glial fibrillary acid protein (GFAP) and monoamine oxidase B (MAO B) expression. 11C-DED is used in positron emission tomography imaging as a marker of astrocytosis in various central nervous system pathologies. It binds irreversibly to MAO B, a glial dimeric enzyme with increased activity in some neurological pathologies. MATERIALS AND METHODS: Binding and internalization studies of 11C-MET and 11C-DED were performed in astrocytoma grade III, glioblastoma grade IV, and radio-resistant glioblastoma grade IV cells. Immunofluorescence was used. RESULTS: 11C-MET specific activity bound to membrane was 9.0%-11.1% and that internalized was 88.9%-91.0%. 11C-DED specific activity bound to membrane was 34.8%-58.0% and that internalized was 38.7%-65.2%. Immunocytochemistry revealed GFAP and MAO B expression. CONCLUSIONS: The expression of MAO B measured by 11C-DED uptake or immunocytochemistry was not significantly different in grade III or IV cells. The GFAP signal was higher for grade IV compared to grade III. 11C-MET uptake was high in all the tumor cells. 11C-DED is a dopamine analogue and the transport across cell membranes is expected to be mediated by DAT receptors present in astrocytes. Reactive astrocytes surround tumor lesions; so the authors suggest that the 11C-DED uptake might be caused by the reactive astrocytosis and not by MAO B expression in tumor cells.
Assuntos
Astrócitos/metabolismo , Astrocitoma/diagnóstico por imagem , Neoplasias Encefálicas/diagnóstico por imagem , Gliose/metabolismo , Compostos Radiofarmacêuticos/farmacocinética , Radioisótopos de Carbono/farmacocinética , Linhagem Celular Tumoral , Deutério/farmacocinética , Proteína Glial Fibrilar Ácida/metabolismo , Humanos , Metionina/farmacocinética , Monoaminoxidase/metabolismo , Tomografia por Emissão de Pósitrons/métodos , Selegilina/farmacocinéticaRESUMO
UNLABELLED: There is an increasing interest about the use of stable isotopes for body composition analysis in pediatrics. To ensure the success of total body water analysis by the deuterium dilution method, it is fundamental to determine the equilibrium time (plateau) of deuterium in the body fluid studied. OBJECTIVES: We report here the equilibration time of deuterium oxide in the saliva of newborns after oral intake of the isotope. METHODS: Twenty healthy term newborn infants, 10 males and 10 females, were analyzed. Saliva was collected from each newborn before the oral administration of a 100 mg/kg dose of deuterium oxide (baseline sample) and then at 1-hour intervals for 5 hours after administration. Deuterium enrichment of saliva was determined by isotope ratio mass spectrometry according to the recommendations of the International Atomic Energy Agency. RESULTS: The plateau time of deuterium in saliva occurred 3 hours after oral administration of the stable isotope. CONCLUSION: These data are essential for further studies on the body composition of newborn infants. To the best of our knowledge, this is the first study regarding the equilibration time of deuterium in the saliva of term newborns.