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L B Houtkooper S B Going T G Lohman A F Roche M Van Loan 《Journal of applied physiology》1992,72(1):366-373
The purposes of this study were to develop and cross-validate the "best" prediction equations for estimating fat-free body mass (FFB) from bioelectrical impedance in children and youth. Predictor variables included height2/resistance (RI) and RI with anthropometric data. FFB was determined from body density (underwater weighing) and body water (deuterium dilution) (FFB-DW) and from age-corrected density equations, which account for variations in FFB water and bone content. Prediction equations were developed using multiple regression analyses in the validation sample (n = 94) and cross-validated in three other samples (n = 131). R2 and standard error of the estimate (SEE) values ranged from 0.80 to 0.95 and 1.3 to 3.7 kg, respectively. The four samples were then combined to develop a recommended equation for estimating FFB from three regression models. R2 and SEE values and coefficients of variation from these regression equations ranged from 0.91 to 0.95, 2.1 to 2.9 kg, and 5.1 to 7.0%, respectively. As a result of all cross-validation analyses, we recommend the equation FFB-DW = 0.61 RI + 0.25 body weight + 1.31, with a SEE of 2.1 kg and adjusted R2 of 0.95. This study demonstrated that RI with body weight can predict FFB with good accuracy in Whites 10-19 yr old. 相似文献
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Temporal genetic variation in Aedes aegypti populations in Ho Chi Minh City (Vietnam) 总被引:3,自引:0,他引:3
Aedes aegypti, the main vector of dengue viruses in Asia, displays variation in population density over time. The larval habitats of this species being unevenly distributed and transient (depending on cycles of drought and flood), the forces generating temporal variation in gene frequencies in populations are studied. We sampled seven mosquito populations from Ho Chi Minh City (Vietnam) and its suburbs on five occasions between April 1999 and August 2000. We investigated genetic variation by studying isoenzyme and microsatellite polymorphism and susceptibility to a dengue 2 virus strain. Ae. aegypti populations collected during the dry season (January-April) showed genetic differentiation (F(ST) = 0.016, P < 10(-6) for isoenzymes) and showed more differentiated infection rates of the dengue 2 virus. The genetic structure of the population is less marked during the rainy season (F(ST) = 0.081, P < 10(-6)). Thus, environmental factors, such as rainfall and factors related to human activity, such as breeding site density and insecticide treatment, control the genetic structure of Ae. aegypti populations in the short term. The implications of studies of this kind for the design of future control programmes are discussed. 相似文献
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Estimates of body fat mass gained during human pregnancy are necessary to assess the composition of gestational weight gained and in studying energy requirements of reproduction. However, commonly used methods of measuring body composition are not valid during pregnancy. We used measurements of total body water (TBW), body density, and bone mineral content (BMC) to apply a four-component model to measure body fat gained in nine pregnant women. Measurements were made longitudinally from before conception; at 8-10, 24-26, and 34-36 wk gestation; and at 4-6 wk postpartum. TBW was measured by deuterium dilution, body density by hydrodensitometry, and BMC by dual-energy X-ray absorptiometry. Body protein was estimated by subtracting TBW and BMC from fat-free mass. By 36 wk of gestation, body weight increased 11.2 +/- 4.4 kg, TBW increased 5.6 +/- 3.3 kg, fat-free mass increased 6.5 +/- 3.4 kg, and fat mass increased 4.1 +/- 3.5 kg. The estimated energy cost of fat mass gained averaged 44,608 kcal (95% confidence interval, -31, 552-120,768 kcal). The large variability in the composition of gestational weight gained among the women was not explained by prepregnancy body composition or by energy intake. This variability makes it impossible to derive a single value for the energy cost of fat deposition to use in estimating the energy requirement of pregnancy. 相似文献
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Whole genome analysis of Vietnamese G2P[4] rotavirus strains possessing the NSP2 gene sharing an ancestral sequence with Chinese sheep and goat rotavirus strains 下载免费PDF全文
Loan Phuong Do Toyoko Nakagomi Punita Gauchan Miho Kaneko Chantal Agbemabiese Anh Duc Dang Osamu Nakagomi 《Microbiology and immunology》2015,59(10):605-613
Because imminent introduction into Vietnam of a vaccine against Rotavirus A is anticipated, baseline information on the whole genome of representative strains is needed to understand changes in circulating strains that may occur after vaccine introduction. In this study, the whole genomes of two G2P[4] strains detected in Nha Trang, Vietnam in 2008 were sequenced, this being the last period during which virtually no rotavirus vaccine was used in this country. The two strains were found to be > 99.9% identical in sequence and had a typical DS‐1 like G2‐P[4]‐I2‐R2‐C2‐M2‐A2‐N2‐T2‐E2‐H2 genotype constellation. Analysis of the Vietnamese strains with > 184 G2P[4] strains retrieved from GenBank/EMBL/DDBJ DNA databases placed the Vietnamese strains in one of the lineages commonly found among contemporary strains, with the exception of the NSP2 and NSP4 genes. The NSP2 genes were found to belong to a previously undescribed lineage that diverged from Chinese sheep and goat rotavirus strains, including a Chinese rotavirus vaccine strain LLR with 95% nucleotide identity; the time of their most recent common ancestor was 1975. The NSP4 genes were found to belong, together with Thai and USA strains, to an emergent lineage (VIII), adding further diversity to ever diversifying NSP4 lineages. Thus, there is a need to enhance surveillance of locally‐circulating strains from both children and animals at the whole genome level to address the effect of rotavirus vaccines on changing strain distribution. 相似文献
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Amanda C. Crisostomo Loan Dang Jyothi L. Digambaranath Andrea C. Klaver David A. Loeffler Jeremiah J. Payne Lynnae M. Smith Adam L. Yokom John M. Finke 《Analytical biochemistry》2015
Surface plasmon resonance was used to investigate the kinetics, affinity, and specificity of binding between anti-Aβ (beta-amyloid) IgG antibodies and oligomeric Aβ. Two factors were needed to accurately characterize the IgG binding kinetics. First, a bivalent model was necessary to properly fit the kinetic association and dissociation sensograms. Second, a high concentration of IgG was necessary to overcome a significant mass transport limitation that existed regardless of oligomer density on the sensor surface. Using high IgG concentrations and bivalent fits, consistent kinetic parameters were found at varying sensor surface ligand densities. A comparison of binding specificity, affinity, and kinetic flux between monoclonal and natural human anti-Aβ IgG antibodies revealed the following findings. First, monoclonal antibodies 6E10 and 4G8 single-site binding affinity is similar between Aβ oligomers and monomers. Second, natural human anti-Aβ IgG binding readily binds Aβ oligomers but does not bind monomers. Third, natural human anti-Aβ IgG binds Aβ oligomers with a higher affinity and kinetic flux than 6E10 and 4G8. Both the current analytical methodology and antibody binding profiles are important for advances in antibody drug development and kinetic biomarker applications for Alzheimer’s disease. 相似文献
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Childhood obesity is a growing problem in the United States. Parental perception of their children's weight status is a key factor that needs to be considered when developing prevention programs for preschool children. Using a randomly selected sample of participants of Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in Los Angeles County, we assessed accuracy of maternal perceptions of their children's weight status by comparing children's weight classification to the mothers' response to the question “Do you consider your child to be overweight, underweight or about right weight for (his) (her) height?” Additionally, we identified possible predictors of accurate maternal perception of their children's weight status by conducting a logistic regression model with child's gender, child's birth weight, maternal age, maternal BMI, maternal education, maternal acculturation level, and maternal language preference as potential predictors. Almost all mothers in the study classified their overweight or obese child as being about the right weight (93.6% and 77.5% of mothers, respectively). Maternal BMI and child's birth weight were the only predictors of maternal perception of their child's weight. Both were negatively associated with accuracy, with higher maternal BMI and higher infant birthweight associated with less accurate maternal perception of child weight. Parents need to be educated on the importance of childhood obesity and how to identify if their children are overweight or obese. If parents fail to recognize that their overweight child is overweight, then it is unlikely that they will recognize that interventions targeting obesity are relevant to their families. 相似文献