The impact of 24 weeks of supervised endurance versus resistance exercise training on left ventricular mechanics in healthy untrained humans.

BACKGROUND: In addition to the well-known cardiac structural adaptation to exercise training, little work examined changes in LV mechanics. With new regional and global indices available we sought to determine the effect of 24 weeks endurance versus resistance training on LV mechanics. METHODS AND RESULTS: 23 male subjects were randomly allocated to either a 24-week endurance- or resistance-training program. Pre- and post-training 2D echocardiographic images were acquired. Global LV mechanics (strain [ε]) were recorded in longitudinal, circumferential and radial planes. Rotation was assessed at apical and basal levels. In addition, longitudinal ε-volume loops, across the cardiac cycle, were constructed from simultaneous LV ε (longitudinal and transverse strain) and volume measurements across the cardiac cycle as a novel measure of LV mechanics. Marginal differences in ε and rotation data were found between groups. Post-training, we found no change in global peak ε data. Peak basal rotation significantly increased after training with changes in the endurance group (-2.2±1.9o to -4.5±3.3o) and the resistance group (-2.9±3.0o to -3.4±2.9o) . LV ε-volume loops revealed a modest rightward shift in both groups. CONCLUSIONS: Whilst most global and regional indices of LV mechanics were not significantly altered, 24 weeks of intense supervised exercise training increased basal rotation. Further studies that assess LV mechanics in larger cohorts of subjects and those with cardiovascular disease and risk factors may reveal important training impacts

Distinct Effects of Blood Flow and Temperature on Cutaneous Microvascular Adaptation

Aims: We performed two experiments to determine whether cutaneous microvascular adaptations in response to repeated core temperature elevation are mediated by increases in skin temperature, and/or, skin blood flow. Methods: Healthy subjects participated for 8-weeks in thrice-weekly bouts of 30mins lower limb heating (40°C). In Study 1, both forearms were “clamped” at basal skin temperature throughout each heating bout (n=9). Study 2 involved identical lower limb heating, with the forearms under ambient conditions (unclamped, n=10). In both studies, a cuff was inflated around one forearm during the heating bouts to assess the contribution of skin blood flow and temperature responses. We assessed forearm skin blood flow responses to both lower limb (systemic reflex) heating, and to local heating of the forearm skin, pre and post intervention. Results: Acutely, lower limb heating increased core temperature (Study 1: +0.63±0.15°C, Study 2: +0.69±0.19°C, P<0.001) and forearm skin blood flow (Study 1: 10±3 vs 125±44, Study 2: 16±9 vs 136±41 PU, P<0.001), with skin responses significantly attenuated in the cuffed forearm (P<0.01). Skin blood flow responses to local heating decreased in Study 1 (clamped forearms, week 0vs8: 1.46±0.52 vs 0.99±0.44 CVC, P<0.05), whereas increases occurred in Study 2 (unclamped; week 0vs8: 1.89±0.57 vs 2.27±0.52 CVC, P<0.05). Cuff placement abolished local adaptations in both studies. Conclusion: Our results indicate that repeated increases in skin blood flow and skin temperature result in increased skin flux responses to local heating, whereas repeated increases in skin blood flow in the absence of change in skin temperature induced the opposite response. Repeated increases in core temperature induce intrinsic microvascular changes, the nature of which are dependent upon both skin blood flow and skin temperature

Left ventricular morphology and function in adolescents: Relations to fitness and fatness.

BACKGROUND: Obesity in childhood predisposes individuals to cardiovascular disease and increased risk of premature all-cause mortality. The aim of this study was to determine differences in LV morphology and function in obese and normal-weight adolescents. Furthermore, relationships between LV outcomes, cardiorespiratory fitness (CRF) and adiposity were explored. METHODS: LV morphology was assessed using magnetic resonance imaging (MRI) in 20 adolescents (11 normal-weight [BMI equivalent to 18kg/m(2)-25kg/m(2)] and 9 obese [BMI equivalent to ≥30kg/m(2)]); 13.3±1.1years, 45% female, Tanner puberty stage 3 [2-4]) using magnetic resonance imaging (MRI). Global longitudinal strain (GLS), strain rate (SR) and traditional echocardiographic indices were used to assess LV function. CRF (peak oxygen consumption), percent body fat (dual-energy x-ray absorptiometry), abdominal adipose tissue (MRI), and blood biochemistry markers were also evaluated. RESULTS: Adolescents with obesity showed significantly poorer LV function compared to normal-weight adolescents (P0.05). Moderate to strong associations between myocardial contractility and relaxation, adiposity, arterial blood pressure and cardiorespiratory fitness were noted (r=0.49-0.71, P<0.05). CONCLUSION: Obesity in adolescence is associated with altered LV systolic and diastolic function. The notable relationship between LV function, CRF and adiposity highlights the potential utility of multidisciplinary lifestyle interventions to treat diminished LV function in this population. CLINICAL TRIAL REGISTRATION: NCT01991106

The Effect of Water Immersion during Exercise on Cerebral Blood Flow

Introduction: Regular exercise induces recurrent increases in cerebrovascular perfusion. In peripheral arteries, such episodic increases in perfusion are responsible for improvement in arterial function and health. We examined the hypothesis that exercise during immersion augments cerebral blood flow velocity compared with intensity-matched land-based exercise. Methods: Fifteen normotensive participants were recruited (26 ± 4 yr, 24.3 ± 1.9 kg·m−2). We continuously assessed mean arterial blood pressure, HR, stroke volume, oxygen consumption, and blood flow velocities through the middle and posterior cerebral arteries before, during, and after 20-min bouts of water- and land-based stepping exercise of matched intensity. The order in which the exercise conditions were performed was randomized between subjects. Water-based exercise was performed in 30°C water to the level of the right atrium. Results: The water- and land-based exercise bouts were closely matched for oxygen consumption (13.3 mL·kg−1·min−1 (95% confidence interval (CI), 12.2–14.6) vs 13.5 mL·kg−1·min−1 (95% CI, 12.1–14.8), P = 0.89) and HR (95 bpm (95% CI, 90–101) vs 96 bpm (95% CI, 91–102), P = 0.65). Compared with land-based exercise, water-based exercise induced an increase in middle cerebral artery blood flow velocity (74 cm·s−1 (95% CI, 66–81) vs 67 cm·s−1 (95% CI, 60–74) P < 0.001), posterior cerebral artery blood flow velocity (47 cm·s−1 (95% CI, 40–53) vs 43 cm·s−1 (95% CI, 37–49), P < 0.001), mean arterial blood pressure (106 mm Hg (95% CI, 100–111) vs 101 mm Hg (95% CI, 95–106), P < 0.001), and partial pressure of expired CO2 (P ≤ 0.001). Conclusions: Our findings suggest that water-based exercise augments cerebral blood flow, relative to land-based exercise of similar intensity, in healthy humans

Repeat controlled human malaria infection of healthy UK adults with blood-stage plasmodium falciparum:Safety and parasite growth dynamics

In endemic settings it is known that natural malaria immunity is gradually acquired following repeated exposures. Here we sought to assess whether similar acquisition of blood-stage malaria immunity would occur following repeated parasite exposure by controlled human malaria infection (CHMI). We report the findings of repeat homologous blood-stage Plasmodium falciparum (3D7 clone) CHMI studies VAC063C (ClinicalTrials.gov NCT03906474) and VAC063 (ClinicalTrials.gov NCT02927145). In total, 24 healthy, unvaccinated, malaria-naïve UK adult participants underwent primary CHMI followed by drug treatment. Ten of these then underwent secondary CHMI in the same manner, and then six of these underwent a final tertiary CHMI. As with primary CHMI, malaria symptoms were common following secondary and tertiary infection, however, most resolved within a few days of treatment and there were no long term sequelae or serious adverse events related to CHMI. Despite detectable induction and boosting of anti-merozoite serum IgG antibody responses following each round of CHMI, there was no clear evidence of anti-parasite immunity (manifest as reduced parasite growth in vivo) conferred by repeated challenge with the homologous parasite in the majority of volunteers. However, three volunteers showed some variation in parasite growth dynamics in vivo following repeat CHMI that were either modest or short-lived. We also observed no major differences in clinical symptoms or laboratory markers of infection across the primary, secondary and tertiary challenges. However, there was a trend to more severe pyrexia after primary CHMI and the absence of a detectable transaminitis post-treatment following secondary and tertiary infection. We hypothesize that this could represent the initial induction of clinical immunity. Repeat homologous blood-stage CHMI is thus safe and provides a model with the potential to further the understanding of naturally acquired immunity to blood-stage infection in a highly controlled setting. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, identifier NCT03906474, NCT02927145

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Socio-cultural determinants of physical activity across the life course: a 'Determinants of Diet and Physical Activity' (DEDIPAC) umbrella systematic literature review

Objective Regular physical activity (PA) reduces the risk of disease and premature death. Knowing factors associated with PA might help reducing the disease and economic burden caused by low activity. Studies suggest that socio-cultural factors may affect PA, but systematic overviews of findings across the life course are scarce. This umbrella systematic literature review (SLR) summarizes and evaluates available evidence on socio-cultural determinants of PA in children, adolescents, and adults. Methods This manuscript was drafted following the recommendations of the ‘Preferred Reporting Items for Systematic reviews and Meta-Analyses’ (PRISMA) checklist. The MEDLINE, Web of Science, Scopus, and SPORTDiscus databases were searched for SLRs and meta-analyses (MAs) on observational studies published in English that assessed PA determinants between January 2004 and April 2016. The methodological quality was assessed and relevant information on socio-cultural determinants and any associations with PA was extracted. The available evidence was evaluated based on the importance of potential determinants and the strength of the evidence. Results Twenty SLRs and three MAs encompassing 657 eligible primary studies investigated potential socio-cultural PA determinants, with predominantly moderate methodological quality. Twenty-nine potential PA determinants were identified that were primarily assessed in children and adolescents and investigated the micro-environmental home/household level. We found probable evidence that receiving encouragement from significant others and having a companion for PA were associated with higher PA in children and adolescents, and that parental marital status (living with partner) and experiencing parental modeling were not associated with PA in children. Evidence for the other potential determinants was limited, suggestive, or non-conclusive. In adults, quantitative and conclusive data were scarce. Conclusions A substantial number of SLRs and MAs investigating potential socio-cultural determinants of PA were identified. Our data suggest that receiving social support from significant others may increase PA levels in children and adolescents, whereas parental marital status is not a determinant in children. Evidence for other potential determinants was limited. This was mainly due to inconsistencies in results on potential socio-cultural determinants of PA across reviews and studies