Commentary on “Why people should run after positive affective experiences instead of health benefits”

Maltagliati et al.1 recently highlighted the vital role of affective experiences in promoting physical activity(PA).The authors suggested that positive affective experiences,rather than health benefits,can tip the balance in favor of PA over sedentary alternatives.The authors proposed a new formal decision model between PA and sedentary alternatives and reported that when health benefits are the unique reason to action,the costs of PA(e.g.,effort)and the subjective value(SV)of sedentary alternatives(V_(sed))are the main drivers of decision-making processes.

Prevalence and factors associated with irritable bowel syndrome among university students in Lebanon:Findings from a cross-sectional study

AIM: To describe the bowel habits and the prevalence of irritable bowel syndrome(IBS) and to investigate the influence of health behavior and social factors on IBS prevalence in university students. METHODS: This cross-sectional study was conducted at five major universities in Greater Beirut and its suburbs, between February and June 2014. Using a convenience sample, a total of 813 students aged 18 years old and above participated in this study. Participants were asked to complete a comprehensive anonymous questionnaire which detailed characteristics on socio-demographic, health-related, and lifestyle factors, as well as IBS. The ROME Ⅲ criteria were used as a tool to ascertain IBS. A χ2 test was used to determine differences between categorical variables; stepwise logistic regression was used to measure the association between IBS and its risk factors.RESULTS: An overall prevalence of IBS of 20% was recorded among university students. The bivariate analysis showed that females were significantly more likely to report having IBS than males(29.1% vs 18.2%, P < 0.01). Those living at the school dormitory or in a private residence(39.5%) were more likely to have IBS than those living with their families(16.3%)(P < 0.01). The multivariate analysis showed that those who had a relatively high family income level(US$ > 2000) were almost 6 times more likely to report havingIBS than their counterparts.CONCLUSION: This is the first study to describe the nature of IBS among young adults in Lebanon. The prevalence of IBS among university students in our sample was higher than that reported in the West.

A Note on Improving Inference of Relative Risk

Relative risk is a popular measure to compare risk of an outcome in the exposed group to the unexposed group. By applying the delta method and Central Limit Theorem, [1] derives two approximate confidence intervals for the relative risk, and [2] approximates the confidence interval for the relative risk via the likelihood ratio statistic. Both of these approximations require sample size to be large. In this paper, by adjusting the likelihood ratio statistic obtained by [2], a new method is proposed to obtain the confidence interval for the relative risk. Simulation results showed that the proposed method is extremely accurate even when the sample size is small.

Group Exercise versus Personal Training for Prostate Cancer Patients: A Pilot Randomized Trial

Background: Previous studies have demonstrated psychosocial and physical benefit from exercise for older men treated with androgen deprivation therapy (ADT) for prostate cancer (PCa). To date, different intervention delivery methods have not been assessed. This study compared the effect of group-based exercise (GBE) to personal training (PT) in men undergoing ADT for PCa. Methods: 13 participants (mean age = 68.2, SD = 7.2) were randomly assigned to GBE or PT for 8 weeks. Participants exercised for 60 minutes three times per week at a moderate-vigorous intensity. Results: 10 participants completed the intervention. At post-intervention, the PT group improved: fatigue, systolic BP, waist circumference, body fat percentage, and maximal leg strength;participants in the GBE group improved leg strength. At 8 weeks, maximal upper body strength in the PT group was greater than the GBE group. There were no adverse events associated with moderate-high intensity training in this population of older men. Conclusion: PT may be more efficacious than GBE in improving several physical fitness outcomes and fatigue in men with PCa who are androgen deprived. Due to the small sample size and attrition, these results require cautious interpretation and confirmation from adequately powered trials.

Mitophagy Regulation in Skeletal Muscle:Effect of Endurance Exercise and Age

Mitochondria are essential energy-providing organelles that are required in the maintenance of healthy skeletal muscle.As such,the removal of damaged mitochondria,through mitophagy,is necessary to maintain mitochondrial quality.In aging muscle,mitochondrial content and function are often found to be reduced compared to young individuals.This occurs despite the fact that measures of mitophagy are elevated,suggesting that mitophagy is insufficiently high to remove all of the dysfunctional organelles in aging muscle.Recent evidence has shown that acute exercise promotes mitophagic signaling,leading to organelle degradation.This exercise-induced signaling is attenuated in aging muscle,suggesting that aging muscle loses its capacity for mitochondrial turnover in response to exercise.This contributes to the reduction in muscle health in elderly individuals.Chronic exercise training improves mitochondrial content and function,even in aging muscle,leading to reduced mitophagy signaling.Thus,exercise training should be prescribed for both young and elderly populations to pro-mote the maintenance of a healthy mitochondrial pool,through the stimulation of both organelle biogenesis and mitophagy.

Hot topics in muscle metabolism and adaptation

This special issue highlights comprehensive reviews and researches on topics in fundamentally important areas of skeletal muscle physiology.1–6 The most important adaptive response of skeletal muscle to exercise,particularly resistant exercise,is increased protein synthesis,which is critical for promoting muscle hypertrophy and/or preventing atrophy.This process plays an essential role in promoting and maintaining skeletal muscle contractile and metabolic functions.

Role of Positive Selection Pressure on the Evolution of H5N1 Hemagglutinin

The surface glycoprotein hemagglutinin （HA） helps the influenza A virus to evade the host immune system by antigenic variation and is a major driving force for viral evolution. In this study, the selection pressure on HA of H5N1 influenza A virus was analyzed using bioinformatics algorithms. Most of the identified positive selection （PS） sites were found to be within or adjacent to epitope sites. Some of the identified PS sites are consistent with previous experimental studies, providing further support to the biological significance of our findings. The highest frequency of PS sites was observed in recent strains isolated during 2005-2007. Phylogenetic analysis was also conducted on HA sequences from various hosts. Viral drift is almost similar in both avian and human species with a progressive trend over the years. Our study reports new mutations in functional regions of HA that might provide markers for vaccine design or can be used to predict isolates of pandemic potential.

A Novel Interpretation of Structural Dot Plots of Genomes Derived from the Analysis of Two Strains of Neisseria meningitidis

Neisseria meningitidis is the agent of invasive meningococcal disease, including cerebral meningitis and septicemia. Because the diseases caused by different clonal groups （sequence types） have their own epidemiological characteristics, it is important to understand the differences among the genomes of the N. meningitidis clonal groups. To this end, a novel interpretation of a structural dot plot of genomes was devised and applied; exact nu- cleotide matches between the genomes ofN. meningitidis serogroup A strain Z2491 and serogroup B strain MC58 were identified, leading to the specification of various structural regions. Known and putative virulence genes for each N. meningitidis strain were then classified into these regions. We found that virulence genes of MC58 tend more to the translocated regions （chromosomal segments in new sequence contexts） than do those of Z2491, notably tending towards the interface between one of the translocated regions and the collinear region. Within the col- linear region, virulence genes tend to occur within 16 kb of gaps in the exact matches. Verification of these tendencies using genes clustered in the cps locus was sufficiently supportive to suggest that these tendencies can be used to focus the search for and understanding of virulence genes and mechanisms of pathogenicity in these two organisms.

Exercise is mitochondrial medicine for muscle

Mitochondria are vital organelles that provide energy for muscle function.When these organelles become dysfunctional,they produce less energy as well as excessive levels of reactive oxygen species which can trigger muscle atrophy,weakness and loss of endurance.In this review,molecular evidence is provided to show that exercise serves as a useful therapeutic countermeasure to overcome mitochondrial dysfunction,even when key regulators of organelle biogenesis are absent.These findings illustrate the complexity and compensatory nature of exercise-induced molecular signaling to transcription,as well as to post-transcriptional events within the mitochondrial synthesis and degradation(i.e.turnover)pathways.Beginning with the first bout of contractile activity,exercise exerts a medicinal effect to improve mitochondrial health and whole muscle function.