Trends in physical activity and sedentary behaviour in adolescence: ethnic and socioeconomic differences

Objective: To assess developmental trends in physical activity and sedentary behaviour in British adolescents in relation to sex, ethnicity and socioeconomic status (SES).Design: A 5-year longitudinal study of a diverse cohort of students aged 11 - 12 years at baseline in 1999.Setting: 36 London schools sampled using a stratified random sampling procedure.Participants: A total of 5863 students categorised as white, black or Asian, and stratified for SES using the Townsend Index.Main outcome measures: Number of days per week of vigorous activity leading to sweating and breathing hard. Hours of sedentary behaviour, including watching television and playing video games. Data were analysed using multilevel, linear, mixed models.Results: Marked reductions in physical activity and increases in sedentary behaviour were noticed between ages 11 - 12 and 15 - 16 years. Boys were more active than girls, and the decline in physical activity was greater in girls (46% reduction) than in boys (23%). Asian students were less active than whites, and this was also true of black girls but not boys. Black students were more sedentary than white students. Levels of sedentary behaviour were greater in respondents from lower SES. Most differences between ethnic and SES groups were present at age 11 years, and did not evolve over the teenage years.Conclusions: Physical activity declines and sedentary behaviour becomes more common during adolescence. Ethnic and SES differences are observed in physical activity and sedentary behaviour in British youth that anticipate adult variations in adiposity and cardiovascular disease risk. These are largely established by age 11 - 12 years, so reversing these patterns requires earlier intervention

High-throughput mapping of protein occupancy identifies functional elements without the restriction of a candidate factor approach

There are a variety of in vivo and in vitro methods to determine the genome-wide specificity of a particular trans-acting factor. However there is an inherent limitation to these candidate approaches. Most biological studies focus on the regulation of particular genes, which are bound by numerous unknown trans-acting factors. Therefore, most biological inquiries would be better addressed by a method that maps all trans-acting factors that bind particular regions rather than identifying all regions bound by a particular trans-acting factor. Here, we present a high-throughput binding assay that returns thousands of unbiased measurements of complex formation on nucleic acid. We applied this method to identify transcriptional complexes that form on DNA regions upstream of genes involved in pluripotency in embryonic stem cells (ES cells) before and after differentiation. The raw binding scores, motif analysis and expression data are used to computationally reconstruct remodeling events returning the identity of the transcription factor(s) most likely to comprise the complex. The most significant remodeling event during ES cell differentiation occurred upstream of the REST gene, a transcriptional repressor that blocks neurogenesis. We also demonstrate how this method can be used to discover RNA elements and discuss applications of screening polymorphisms for allelic differences in binding

Obesity and cardiovascular disease risk factors among adult Sudanese

Subjects and methods: In this study, the effect of obesity on the development of dyslipidemia, hypertension and glucose intolerance among Sudanese adults attending weight reduction programs was investigated. According to the BMI (Body mass index), 98 overweight/obese and 60 normal weight adults were included. Anthropometric measures were taken, lipid profile and C – reactive protein (CRP) were determined using commercial kits.Results: Obesity related dyslipidemia seems to affect overweight/obese males more than females. On the other hand, overweight /obesity among females, not like males, was found to be associated with high blood pressure probably due inflammation, as determined by CRP level.Conclusion and recommendation: Obesity related dyslipidemia is more prominent among males while obesity related hypertension is a phenomenon among females probably due to release of CRP. We recommend a more detailed study of inflammatory cytokines, in relation to obesity, that mayreflect the mass and/or activity of the adipose tissue.Key words: overweight, dyslipedemia, CVD

Mutation studies of the gene encoding YuiC, a stationary phase survival protein in Bacillus subtilis

Aims: YuiC is a stationary phase survival (Sps) protein from the Firmicute Bacillus subtilis that possesses muralytic activity to cleave bacterial cell-wall peptidoglycan. It has a small lytic transglycosylase (MltA) fold analogous to the resuscitation promoting factors (Rpfs) of Actinobacteria which have a hybrid of a mini lysozyme and soluble lytic transglycosylase (Slt35/70) fold. The present study aimed at identifying key residues of YuiC/Sps that are catalytically active and studying the effect of B. subtilis cell growth upon sps/yuiC deletion. Methodology and results: Four forms of mutated yuiC were created through Site-directed, Ligase-Independent Mutagenesis Polymerase Chain Reaction (SLIM PCR) that include the substitutions of D129A, D151A, D162A and K102A. These individual mutated yuiC genes were cloned and expressed in the Escherichia coli BL21 (DE3) expression system and subsequently purified to homogeneity using affinity, cation exchange and size exclusion chromatography. The D129A variant was shown to be insoluble, indicating its role in maintaining the right protein folding of YuiC. The remaining three variants resulted in soluble proteins but were inactive on zymograms indicating that they may be responsible for catalysis. B. subtilis cells harbouring individual sps genes (yuiC, yabE, yocH and yorM) knocked out showed stationary phase defects and altered colony morphologies compared to the wild type. Conclusion, significance and impact of study: This study has identified the key residues involved in catalysis of YuiC, which are the D151, D162 and K102. These are conserved in Sps domains. The catalytic mechanism of YuiC is similar to the mechanism reported for Neisseria gonorrhoeae MltA. sps/yuiC knock outs have implied that each sps/yuiC has a significant role on B. subtilis late growth stage. The B. subtilis YuiC/Sps model has given an insight into Sps functions in the final growth stage of the Firmicutes, which members include etiologic agents of anthrax, botulism and listeriosis. Inhibition of Sps protein may inactivate pathogen replication and facilitate entrance into a non-contagious dormant sporulation stage

On the Price of Anarchy of Highly Congested Nonatomic Network Games

We consider nonatomic network games with one source and one destination. We examine the asymptotic behavior of the price of anarchy as the inflow increases. In accordance with some empirical observations, we show that, under suitable conditions, the price of anarchy is asymptotic to one. We show with some counterexamples that this is not always the case. The counterexamples occur in very simple parallel graphs.Comment: 26 pages, 6 figure

Computational modeling of low-density lipoprotein accumulation at the carotid artery bifurcation after stenting

Restenosis typically occurs in regions of low and oscillating wall shear stress, which also favor the accumulation of atherogenic macromolecules such as low-density lipoprotein (LDL). This study aims to evaluate LDL transport and accumulation at the carotid artery bifurcation following carotid artery stenting (CAS) by means of computational simulation. The computational model consists of coupled blood flow and LDL transport, with the latter being modeled as a dilute substance dissolved in the blood and transported by the flow through a convection-diffusion transport equation. The endothelial layer was assumed to be permeable to LDL, and the hydraulic conductivity of LDL was shear-dependent. Anatomically realistic geometric models of the carotid bifurcation were built based on pre- and post-stent computed tomography (CT) scans. The influence of stent design was investigated by virtually deploying two different types of stents (open- and closed-cell stents) into the same carotid bifurcation model. Predicted LDL concentrations were compared between the post-stent carotid models and the relatively normal contralateral model reconstructed from patient-specific CT images. Our results show elevated LDL concentration in the distal section of the stent in all post-stent models, where LDL concentration is 20 times higher than that in the contralateral carotid. Compared with the open-cell stents, the closed-cell stents have larger areas exposed to high LDL concentration, suggesting an increased risk of stent restenosis. This computational approach is readily applicable to multiple patient studies and, once fully validated against follow-up data, it can help elucidate the role of stent strut design in the development of in-stent restenosis after CAS

Cell wall peptidoglycan in Mycobacterium tuberculosis: An Achilles’ heel for the TB-causing pathogen

Tuberculosis (TB), caused by the intracellular pathogen Mycobacterium tuberculosis, remains one of the leading causes of mortality across the world. There is an urgent requirement to build a robust arsenal of effective antimicrobials, targeting novel molecular mechanisms to overcome the challenges posed by the increase of antibiotic resistance in TB. Mycobacterium tuberculosis has a unique cell envelope structure and composition, containing a peptidoglycan layer that is essential for maintaining cellular integrity and for virulence. The enzymes involved in the biosynthesis, degradation, remodelling and recycling of peptidoglycan have resurfaced as attractive targets for anti-infective drug discovery. Here, we review the importance of peptidoglycan, including the structure, function and regulation of key enzymes involved in its metabolism. We also discuss known inhibitors of ATP-dependent Mur ligases, and discuss the potential for the development of pan-enzyme inhibitors targeting multiple Mur ligases

A coproduct structure on the formal affine Demazure algebra

In the present paper we generalize the coproduct structure on nil Hecke rings introduced and studied by Kostant-Kumar to the context of an arbitrary algebraic oriented cohomology theory and its associated formal group law. We then construct an algebraic model of the T-equivariant oriented cohomology of the variety of complete flags.Comment: 28 pages; minor revision of the previous versio