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.     

Negative Feedback Synchronizes Islets of Langerhans

Insulin is released from the pancreas in pulses with a period of ∼ 5 min. These oscillatory insulin levels are essential for proper liver utilization and perturbed pulsatility is observed in type 2 diabetes. What coordinates the many islets of Langerhans throughout the pancreas to produce unified oscillations of insulin secretion? One hypothesis is that coordination is achieved through an insulin-dependent negative feedback action of the liver onto the glucose level. This hypothesis was tested in an in vitro setting using a microfluidic system where the population response from a group of islets was input to a model of hepatic glucose uptake, which provided a negative feedback to the glucose level. This modified glucose level was then delivered back to the islet chamber where the population response was again monitored and used to update the glucose concentration delivered to the islets. We found that, with appropriate parameters for the model, oscillations in islet activity were synchronized. This approach demonstrates that rhythmic activity of a population of physically uncoupled islets can be coordinated by a downstream system that senses islet activity and supplies negative feedback. In the intact animal, the liver can play this role of the coordinator of islet activity.     

Altered SK3/KCa2.3-mediated migration in adenomatous polyposis coli (Apc) mutated mouse colon epithelial cells

Lost of adenomatous polyposis coli gene (Apc) disturbs the migration of intestinal epithelial cells but the mechanisms have not been fully characterized. Since we have demonstrated that SK3/KCa2.3 channel promotes cancer cell migration, we hypothesized that Apc mutation may affect SK3/KCa2.3 channel-mediated colon epithelial cell motility. We report evidence that SK3/KCa2.3 channel promotes colon epithelial cells motility. Following Apc mutation SK3/KCa2.3 expression is largely reduced leading to a suppression of the SK3/KCa2.3 channel mediated-cell migration. Our findings reveal a previously unknown function of the SK3/KCa2.3 channel in epithelial colonic cells, and suggest that Apc is a powerful regulator SK3/KCa2.3 channel.     

Mechanical stretch inhibits oxidized low density lipoprotein-induced apoptosis in vascular smooth muscle cells by up-regulating integrin alphavbeta3 and stablization of PINCH-1

To determine the mechanisms involved in regulating the balance between apoptosis and survival in vascular smooth muscle cells (VSMC), we studied anti-apoptotic stimuli that can counteract pro-apoptotic events in the process of early atherosclerotic lesions formation. Such a process involves VSMC accumulation even in the presence of oxidized low density lipoprotein (Ox-LDL). In the arch of the aorta, we find that integrin beta3 is higher than in descending arteries. In the advanced atherosclerosis lesion, we found an inverse correlation between the level of integrin beta3 and apoptosis (deoxynucleotidyltransferase-mediated dUTP nick end labeling-positive). We also found an increase in integrin alphaVbeta3 (but not integrin beta1) expression in VSMC that are subjected to cyclic stretch. VSMC subjected to stretch as well as VSMC with forced expression of alphaVbeta3 were demonstrated to be resistant to Ox-LDL-induced cytoskeleton disruption and apoptosis. The anti-apoptotic effect of stretch was abolished by treatment of VSMC with small interfering RNA against integrin beta3 as well as VSMC isolated from integrin beta3 knock-out mice. Disruption of the cytoskeleton abolished the protective effect of stretch or alphaVbeta3 overexpression on Ox-LDL-induced activation of Bax and apoptosis. We also demonstrated that stretch-mediated protection of Ox-LDL-induced apoptosis involved stabilization of PINCH-1; Ox-LDL decreased the level of PINCH-1, but the application of mechanical stretch or overexpression of either integrin beta1 or integrin beta3 prevented its down-regulation. In the arteries of integrin beta3 null mice, there were lower levels of PINCH-1 and ILK-1. Moreover, deletion of integrin beta3 in VSMC abolished the stretch protective effect on PINCH-1. Small interfering RNA-mediated knockdown of PINCH-1 disrupted the cytoskeleton and caused apoptosis of VSMC. These findings provided experimental evidence that mechanical stretch acted as a survival factor in the arches of aortas. Furthermore, mechanical stretch prevented VSMC from apoptosis via a mechanism that involves alphaVbeta3 integrin expression, stabilization of PINCH-1, and remodeling of the cytoskeleton.     

The identification of potent, selective, and bioavailable cathepsin S inhibitors

Highly potent, selective, and bioavailable inhibitors of human, mouse, or rat cathepsin S are described. The key structural features combine a sulfonyl moiety attached to a large group in P2 and a small substituent in P3.     

The Arabidopsis ATNRT2.7 nitrate transporter controls nitrate content in seeds

In higher plants, nitrate is taken up by root cells where Arabidopsis thaliana NITRATE TRANSPORTER2.1 (ATNRT2.1) chiefly acts as the high-affinity nitrate uptake system. Nitrate taken up by the roots can then be translocated from the root to the leaves and the seeds. In this work, the function of the ATNRT2.7 gene, one of the seven members of the NRT2 family in Arabidopsis, was investigated. High expression of the gene was detected in reproductive organs and peaked in dry seeds. beta-Glucuronidase or green fluorescent protein reporter gene expression driven by the ATNRT2.7 promoter confirmed this organ specificity. We assessed the capacity of ATNRT2.7 to transport nitrate in Xenopus laevis oocytes or when it is expressed ectopically in mutant plants deficient in nitrate transport. We measured the impact of an ATNRT2.7 mutation and found no difference from the wild type during vegetative development. By contrast, seed nitrate content was affected by overexpression of ATNRT2.7 or a mutation in the gene. Finally, we showed that this nitrate transporter protein was localized to the vacuolar membrane. Our results demonstrate that ATNRT2.7 plays a specific role in nitrate accumulation in the seed.     

Overexpression of phospholipase C-gamma1 inhibits NGF-induced neuronal differentiation by proliferative activity of SH3 domain

Since the biological role of phospholipase C (PLC) gamma1 in neuronal differentiation still barely understood, here, we report that overexpression of PLC gamma1 inhibits neurite outgrowth and prolonged proliferation ability of PLC gamma1 contribute to the alteration of cell cycle regulatory proteins, subsequently exiting from cell growth arrest. Deletion of the SH3 or the entire SH223 domains, but not deletion of the N-SH2 or both the N-SH2 and C-SH2 domains expressing cells abolishes the differentiation-inhibitory effects of PLC gamma1, displaying depression of PCNA and elevation of cyclin D1. Moreover, these cells declined CDK1 and CDK2 expression and increased p21WAF-1, accompanying with G2/M accumulation. Some antiproliferative reagents are able to restore neurite outgrowth in PLC gamma1 cells, showing G2/M arrest. Our findings suggest that the proliferation activity of PLC gamma1 via its SH3 domain may be coupled with the flight from growth arrest by NGF, thereby inhibiting neuronal differentiation.     

Focus: Addiction: A Feasibility Study of Bilateral Anodal Stimulation of the Prefrontal Cortex Using High-Definition Electrodes in Healthy Participants

Transcranial direct current stimulation (tDCS) studies often use one anode to increase cortical excitability in one hemisphere. However, mental processes may involve cortical regions in both hemispheres. This study’s aim was to assess the safety and possible effects on affect and working memory of tDCS using two anodes for bifrontal stimulation. A group of healthy subjects participated in two bifrontal tDCS sessions on two different days, one for real and the other for sham stimulation. They performed a working memory task and reported their affect immediately before and after each tDCS session. Relative to sham, real bifrontal stimulation did not induce significant adverse effects, reduced decrement in vigor-activity during the study session, and did not improve working memory. These preliminary findings suggest that bifrontal anodal stimulation is feasible and safe and may reduce task-related fatigue in healthy participants. Its effects on neuropsychiatric patients deserve further study.