Relationship between Body Mass Index and Percent Body Fat in Vietnamese: Implications for the Diagnosis of Obesity

BackgroundThe burden of obesity in Vietnam has not been well defined because there is a lack of reference data for percent body fat (PBF) in Asians. This study sought to define the relationship between PBF and body mass index (BMI) in the Vietnamese population.MethodsThe study was designed as a comparative cross-sectional investigation that involved 1217 individuals of Vietnamese background (862 women) aged 20 years and older (average age 47 yr) who were randomly selected from the general population in Ho Chi Minh City. Lean mass (LM) and fat mass (FM) were measured by DXA (Hologic QDR 4500). PBF was derived as FM over body weight.ResultsBased on BMI ≥30, the prevalence of obesity was 1.1% and 1.3% for men and women, respectively. The prevalence of overweight and obesity combined (BMI ≥25) was ~24% and ~19% in men and women, respectively. Based on the quadratic relationship between BMI and PBF, the approximate PBF corresponding to the BMI threshold of 30 (obese) was 30.5 in men and 41 in women. Using the criteria of PBF >30 in men and PBF >40 in women, approximately 15% of men and women were considered obese.ConclusionThese data suggest that body mass index underestimates the prevalence of obesity. We suggest that a PBF >30 in men or PBF >40 in women is used as criteria for the diagnosis of obesity in Vietnamese adults. Using these criteria, 15% of Vietnamese adults in Ho Chi Minh City was considered obese.     

Having a Lot of a Good Thing: Multiple Important Group Memberships as a Source of Self-Esteem

Membership in important social groups can promote a positive identity. We propose and test an identity resource model in which personal self-esteem is boosted by membership in additional important social groups. Belonging to multiple important group memberships predicts personal self-esteem in children (Study 1a), older adults (Study 1b), and former residents of a homeless shelter (Study 1c). Study 2 shows that the effects of multiple important group memberships on personal self-esteem are not reducible to number of interpersonal ties. Studies 3a and 3b provide longitudinal evidence that multiple important group memberships predict personal self-esteem over time. Studies 4 and 5 show that collective self-esteem mediates this effect, suggesting that membership in multiple important groups boosts personal self-esteem because people take pride in, and derive meaning from, important group memberships. Discussion focuses on when and why important group memberships act as a social resource that fuels personal self-esteem.     

Amyloid-Related Memory Decline in Preclinical Alzheimer’s Disease Is Dependent on APOE ε4 and Is Detectable over 18-Months

High levels of β-amyloid (Aβ) in the brain and carriage of the APOE ε4 allele have each been linked to cognitive impairment in cognitively normal (CN) older adults. However, the relationship between these two biomarkers and cognitive decline is unclear. The aim of this study was to investigate the relationship between cerebral Aβ level, APOE ε4 carrier status, and cognitive decline over 18 months, in 317 cognitively healthy (CN) older adults (47.6% males, 52.4% females) aged between 60 and 89 years (Mean = 69.9, SD = 6.8). Cognition was assessed using the Cogstate Brief Battery (CBB) and the California Verbal Learning Test, Second Edition (CVLT-II). Planned comparisons indicated that CN older adults with high Aβ who were also APOE ε4 carriers demonstrated the most pronounced decline in learning and working memory. In CN older adults who were APOE ε4 non-carriers, high Aβ was unrelated to cognitive decline in learning and working memory. Carriage of APOE ε4 in CN older adults with low Aβ was associated with a significantly increased rate of decline in learning and unexpectedly, improved cognitive performance on measures of verbal episodic memory over 18 months. These results suggest that Aβ and APOE ε4 interact to increase the rate of cognitive decline in CN older adults and provide further support for the use of Aβ and APOE ε4 as biomarkers of early Alzheimer’s disease.     

Physical Activity in Vietnam: Estimates and Measurement Issues

IntroductionOur aims were to provide the first national estimates of physical activity (PA) for Vietnam, and to investigate issues affecting their accuracy.MethodsMeasurements were made using the Global Physical Activity Questionnaire (GPAQ) on a nationally-representative sample of 14706 participants (46.5% males, response 64.1%) aged 25−64 years selected by multi-stage stratified cluster sampling.ResultsApproximately 20% of Vietnamese people had no measureable PA during a typical week, but 72.9% (men) and 69.1% (women) met WHO recommendations for PA by adults for their age. On average, 52.0 (men) and 28.0 (women) Metabolic Equivalent Task (MET)-hours/week (largely from work activities) were reported. Work and total PA were higher in rural areas and varied by season. Less than 2% of respondents provided incomplete information, but an additional one-in-six provided unrealistically high values of PA. Those responsible for reporting errors included persons from rural areas and all those with unstable work patterns. Box-Cox transformation (with an appropriate constant added) was the most successful method of reducing the influence of large values, but energy-scaled values were most strongly associated with pathophysiological outcomes.ConclusionsAround seven-in-ten Vietnamese people aged 25–64 years met WHO recommendations for total PA, which was mainly from work activities and higher in rural areas. Nearly all respondents were able to report their activity using the GPAQ, but with some exaggerated values and seasonal variation in reporting. Data transformation provided plausible summary values, but energy-scaling fared best in association analyses.     

Initial impacts and field validation of host range for Boreioglycaspis melaleucae Moore (Hemiptera: Psyllidae), a biological control agent of the invasive tree Melaleuca quinquenervia (Cav.) Blake (Myrtales: Myrtaceae: Leptospermoideae)

Invasion of south Florida wetlands by the Australian paperbark tree, Melaleuca quinquenervia (Cav.) S.T. Blake (melaleuca), has caused adverse economic and environmental impacts. The tree's biological attributes and favorable ambient biophysical conditions combine to complicate efforts to restore and maintain south Florida ecosystems. Management requires an integrated strategy that deploys multiple biological control agents to forestall reinvasion and to supplement other control methods, thereby lessening recruitment and regeneration after removal of existing trees. This biological control program began during 1997 when an Australian weevil, Oxyops vitiosa (Pascoe), was released. A second Australian insect, the melaleuca psyllid (Boreioglycaspis melaleucae Moore), first introduced during 2002, has also widely established. After inoculation of the psyllid in a field study, only 40% of seedlings survived herbivory treatments compared with 95% survival in controls. The resultant defoliation also reduced growth of the surviving seedlings. A weevil-induced decline at a site comprised mainly of coppicing stumps had slowed after a 70% reduction. Psyllids colonized the site, and 37% of the remaining coppices succumbed within 10 mo. The realized ecological host range of B. melaleucae was restricted to M. quinquenervia; 18 other nontarget plant species predicted to be suboptimal or nonhosts during laboratory host range testing were unaffected when interspersed with psyllid-infested melaleuca trees in a common garden study. Evaluations are ongoing, but B. melaleucae is clearly reducing seedling recruitment and stump regrowth without adversely impacting other plant species. Manifestation of impacts on mature trees will require more time, but initial indications suggest that the psyllid will be an effective supplement to the weevil.     

Structural Features of Membrane-bound Glucocerebrosidase and α-Synuclein Probed by Neutron Reflectometry and Fluorescence Spectroscopy

Mutations in glucocerebrosidase (GCase), the enzyme deficient in Gaucher disease, are a common genetic risk factor for the development of Parkinson disease and related disorders, implicating the role of this lysosomal hydrolase in the disease etiology. A specific physical interaction exists between the Parkinson disease-related protein α-synuclein (α-syn) and GCase both in solution and on the lipid membrane, resulting in efficient enzyme inhibition. Here, neutron reflectometry was employed as a first direct structural characterization of GCase and α-syn·GCase complex on a sparsely-tethered lipid bilayer, revealing the orientation of the membrane-bound GCase. GCase binds to and partially inserts into the bilayer with its active site most likely lying just above the membrane-water interface. The interaction was further characterized by intrinsic Trp fluorescence, circular dichroism, and surface plasmon resonance spectroscopy. Both Trp fluorescence and neutron reflectometry results suggest a rearrangement of loops surrounding the catalytic site, where they extend into the hydrocarbon chain region of the outer leaflet. Taking advantage of contrasting neutron scattering length densities, the use of deuterated α-syn versus protiated GCase showed a large change in the membrane-bound structure of α-syn in the complex. We propose a model of α-syn·GCase on the membrane, providing structural insights into inhibition of GCase by α-syn. The interaction displaces GCase away from the membrane, possibly impeding substrate access and perturbing the active site. GCase greatly alters membrane-bound α-syn, moving helical residues away from the bilayer, which could impact the degradation of α-syn in the lysosome where these two proteins interact.     

Quantifying the emergence of dengue in Hanoi, Vietnam: 1998-2009

Background

An estimated 2.4 billion people live in areas at risk of dengue transmission, therefore the factors determining the establishment of endemic dengue in areas where transmission suitability is marginal is of considerable importance. Hanoi, Vietnam is such an area, and following a large dengue outbreak in 2009, we set out to determine if dengue is emerging in Hanoi.

Methods and Principal Findings

We undertook a temporal and spatial analysis of 25,983 dengue cases notified in Hanoi between 1998 and 2009. Age standardized incidence rates, standardized age of infection, and Standardized Morbidity Ratios (SMR) were calculated. A quasi-Poisson regression model was used to determine if dengue incidence was increasing over time. Wavelet analysis was used to explore the periodicity of dengue transmission and the association with climate variables. After excluding the two major outbreak years of 1998 and 2009 and correcting for changes in population age structure, we identified a significant annual increase in the incidence of dengue cases over the period 1999–2008 (incidence rate ratio  = 1.38, 95% confidence interval  = 1.20–1.58, p value  = 0.002). The age of notified dengue cases in Hanoi is high, with a median age of 23 years (mean 26.3 years). After adjusting for changes in population age structure, there was no statistically significant change in the median or mean age of dengue cases over the period studied. Districts in the central, highly urban, area of Hanoi have the highest incidence of dengue (SMR>3).

Conclusions

Hanoi is a low dengue transmission setting where dengue incidence has been increasing year on year since 1999. This trend needs to be confirmed with serological surveys, followed by studies to determine the underlying drivers of this emergence. Such studies can provide insights into the biological, demographic, and environmental changes associated with vulnerability to the establishment of endemic dengue.     

BMI not WHR modulates BOLD fMRI responses in a sub-cortical reward network when participants judge the attractiveness of human female bodies

In perceptual terms, the human body is a complex 3d shape which has to be interpreted by the observer to judge its attractiveness. Both body mass and shape have been suggested as strong predictors of female attractiveness. Normally body mass and shape co-vary, and it is difficult to differentiate their separate effects. A recent study suggested that altering body mass does not modulate activity in the reward mechanisms of the brain, but shape does. However, using computer generated female body-shaped greyscale images, based on a Principal Component Analysis of female bodies, we were able to construct images which covary with real female body mass (indexed with BMI) and not with body shape (indexed with WHR), and vice versa. Twelve observers (6 male and 6 female) rated these images for attractiveness during an fMRI study. The attractiveness ratings were correlated with changes in BMI and not WHR. Our primary fMRI results demonstrated that in addition to activation in higher visual areas (such as the extrastriate body area), changing BMI also modulated activity in the caudate nucleus, and other parts of the brain reward system. This shows that BMI, not WHR, modulates reward mechanisms in the brain and we infer that this may have important implications for judgements of ideal body size in eating disordered individuals.     

Bcl-XL as a fusion protein for the high-level expression of membrane-associated proteins

An Escherichia coli plasmid vector for the high-level expression of hydrophobic membrane proteins is described. The plasmid, pBCL, directs the expression of a target polypeptide fused to the C terminus of a mutant form of the anti-apoptotic Bcl-2 family protein, Bcl-XL, where the hydrophobic C terminus has been deleted, and Met residues have been mutated to Leu to facilitate CNBr cleavage after a single Met inserted at the beginning of the target sequence. Fusion protein expression is in inclusion bodies, simplifying the protein purification steps. Here we report the high-level production of PLM, a membrane protein that is a member of the FXYD family of tissue-specific and physiological-state-specific auxiliary subunits of the Na,K-ATPase, expressed abundantly in heart and skeletal muscle. We demonstrate that milligram quantities of pure, isotopically labeled protein can be obtained easily and in little time with this system.     

Influence of language and ancestry on genetic structure of contiguous populations: A microsatellite based study on populations of Orissa

Background

Although cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, the severity of disease is highly variable indicating the influence of modifier genes. The intestines of Cftr deficient mice (CF mice: Cftr ^tm1Unc ) are prone to obstruction by excessive mucus accumulation and are used as a model of meconium ileus and distal intestinal obstruction syndrome. This phenotype is strongly dependent on the genetic background of the mice. On the C57Bl/6 background, the majority of CF mice cannot survive on solid mouse chow, have inflammation of the small intestine, and are about 30% smaller than wild type littermates. In this work potential modifier loci of the CF intestinal phenotype were identified.

Results

CF mice on a mixed genetic background (95% C57Bl/6 and 5% 129Sv) were compared to CF mice congenic on the C57Bl/6 background for several parameters of the intestinal CF phenotype. CF mice on the mixed background exhibit significantly greater survival when fed dry mouse chow, have reduced intestinal inflammation as measured by quantitative RT-PCR for marker genes, have near normal body weight gain, and have reduced mucus accumulation in the intestinal crypts. There was an indication of a gender effect for body weight gain: males did not show a significant improvement at 4 weeks of age, but were of normal weight at 8 weeks, while females showed improvement at both 4 and 8 weeks. By a preliminary genome-wide PCR allele scanning, three regions were found to be potentially associated with the milder phenotype. One on chr.1, defined by marker D1Mit36, one on chr. 9 defined by marker D9Mit90, and one on chr. 10, defined by marker D10Mit14.

Conclusion

Potential modifier regions were found that have a positive impact on the inflammatory phenotype of the CF mouse small intestine and animal survival. Identification of polymorphisms in specific genes in these regions should provide important new information about genetic modifiers of the CF intestinal phenotype.