Accumulating exercise and postprandial health in adolescents

ArticleCopyright © 2015 Published by Elsevier Inc.Purpose: To examine the influence of exercise intensity on postprandial health outcomes in adolescents when exercise is accumulated throughout the day. Methods: 19 adolescents (9 male, 13.7 ± 0.4 y) completed three 1-day trials in a randomised order: 1) rest (CON); or four bouts of 2) 2 x 1 min cycling at 90% peak power with 75 s recovery (high-intensity interval exercise; HIIE); or 3) cycling at 90% of the gas exchange threshold (moderate-intensity exercise; MIE), which was work-matched to HIIE. Each bout was separated by 2 hours. Participants consumed a high fat milkshake for breakfast and lunch. Postprandial triacylglycerol (TAG), glucose, systolic blood pressure (SBP) and fat oxidation were assessed throughout the day. Results: There was no effect of trial on total area under the curve (TAUC) for TAG (P=0.87). TAUC-glucose was lower in HIIE compared to CON (P=0.03, ES=0.42) and MIE (P=0.04, ES=0.41), with no difference between MIE and CON (P=0.89, ES=0.04). Postprandial SBP was lower in HIIE compared to CON (P=0.04, ES=0.50) and MIE (P=0.04, ES=0.40), but not different between MIE and CON (P=0.52, ES=0.11). Resting fat oxidation was increased in HIIE compared to CON (P=0.01, ES=0.74) and MIE (P=0.05, ES=0.51), with no difference between MIE and CON (P=0.37, ES=0.24). Conclusion: Neither exercise trial attenuated postprandial lipaemia. However, accumulating brief bouts of HIIE, but not MIE, reduced postprandial plasma glucose and SBP, and increased resting fat oxidation in adolescent boys and girls. The intensity of accumulated exercise may therefore have important implications for health outcomes in youth.Sport and Health Sciences Research Committee, College of Life and Environmental Sciences, University of Exeter

Photochemical Spin Dynamics of the Vitamin B12 Derivative, Methylcobalamin

Derivatives of vitamin B12 are six-coordinate cobalt corrinoids found in humans, other animals and micro-organisms. By acting as enzymatic cofactors and photoreceptor chromophores they serve vital metabolic and photoprotective functions. Depending on the context, the chemical mechanisms of the biologically-active derivatives of B12 – methylcobalamin (MeCbl) and 5’-deoxyadenosylcobalamin (AdoCbl) – can be very different from one another. The extent to which this chemistry is tuned by the upper axial ligand, however, is not yet clear. Here, we have used a combination of time-resolved FT-EPR, magnetic field effect experiments and spin dynamic simulations to reveal that the upper axial ligand alone only results in relatively minor changes to the photochemical spin dynamics of B12. By studying the photolysis of MeCbl, we find that, much like for AdoCbl, the initial (or ‘geminate’) radical pairs are born predominantly in the singlet spin-state and thus originate from singlet excited-state precursors. This is in contrast to the triplet radical pairs and precursors proposed previously. Unlike AdoCbl, the extent of geminate recombination is limited following MeCbl photolysis, resulting in significant distortions to the FT-EPR signal caused by polarization from spin-correlated methyl-methyl radical ‘f-pairs’ formed following rapid diffusion. Despite the photophysical mechanism that precedes photolysis of MeCbl showing a wavelength-dependence, the subsequent spin dynamics appear to be largely independent of excitation wavelength, again much like for AdoCbl. Our data finally provide clarity to what in the literature to date has been a confused and contradictory picture. We conclude that, although the upper axial position of MeCbl and AdoCbl does impact their reactivity to some extent, the remarkable biochemical diversity of these fascinating molecules is most likely a result of tuning by their protein environment

Who bullies whom at a garden feeder? Interspecific agonistic interactions of small passerines during a cold winter

Interspecific agonistic interactions are important selective factors for maintaining ecological niches of different species, but their outcome is difficult to predict a priori. Here, we examined the direction and intensity of interspecific interactions in an assemblage of small passerines at a garden feeder, focussing on three finch species of various body sizes. We found that large and mediumsized birds usually initiated and won agonistic interactions with smaller species. Also, the frequency of fights increased with decreasing differences in body size between the participants. Finally, the probability of engaging in a fight increased with the number of birds at the feeder

Cirsium species show disparity in patterns of genetic variation at their range-edge, despite similar patterns of reproduction and isolation

Genetic variation was assessed across the UK geographical range of Cirsium acaule and Cirsium heterophyllum. A decline in genetic diversity and increase in population divergence approaching the range edge of these species was predicted based on parallel declines in population density and seed production reported seperately. Patterns were compared with UK populations of the widespread Cirsium arvense.Populations were sampled along a latitudinal transect in the UK and genetic variation assessed using microsatellite markers. Cirsium acaule shows strong isolation by distance, a significant decline in diversity and an increase in divergence among range-edge populations. Geographical structure is also evident in C. arvense, whereas no such patterns are seen in C.heterophyllum. There is a major disparity between patterns of genetic variation in C. acaule and C. heterophyllum despite very similar patterns in seed production and population isolation in these species. This suggests it may be misleading to make assumptions about the geographical structure of genetic variation within species based solely on the present-day reproduction and distribution of populations

Field assessment of the potential for small scale co-cultivation of seaweed and shellfish to regulate nutrients and plankton dynamics

This is the final version. Available on open access from Elsevier via the DOI in this recordData Availability; Data will be made available on request.The co-cultivation of seaweed alongside shellfish has the potential to regulate local dissolved nutrient concentrations and consequently affect plankton dynamics. Evidence for this has until now come largely from computational modelling and laboratory studies, rather than field studies. Here we report on weekly/bi-weekly profiling of inorganic nutrient concentrations (nitrate, nitrite, ammonium, phosphate, and silicate) over two years (2019–2020) at three sampling stations across a small-scale (16 ha) kelp and mussel farm in Porthallow Bay, Cornwall, UK. Nutrient concentrations were measured in conjunction with a range of related environmental variables, including water temperature, salinity, clarity, and phyto- and zoo- plankton abundance, biomass and community composition. These environmental data were also supplemented with river discharge data. Our results indicate typical seasonal variations in chemical (nutrient), physical (hydrographic), and biological (plankton) parameters across all three sampling stations and no significant reductions in inorganic nutrient concentrations in the water column downstream from the integrated kelp and shellfish farm. We conclude that the effectiveness of nutrient regulation by integrating seaweed and shellfish aquaculture will depend on local climatic and hydro-geochemical conditions (affecting background nutrient inputs), as well as the design and scale of integrated multi–trophic aquaculture (IMTA) systems.Natural Environment Research Council (NERC)European Maritime and Fisheries FundFishmongers' Company's Charitable Trust, UKCornish Seaweed CompanyWestcountry Mussels of FoweyCornwall Inshore Fisheries Conservation AuthorityUKR

Hypercalcemia after transplant nephrectomy in a hemodialysis patient: a case report

<p>Abstract</p> <p>Introduction</p> <p>Hypercalcemia is a complication often seen in chronic hemodialysis patients. A rare cause of this condition is sarcoidosis. Its highly variable clinical presentation is challenging. Especially in patients suffering chronic kidney graft failure the nonspecific constitutional symptoms of sarcoidosis like fever, weight loss, arthralgia and fatigue may be easily misleading.</p> <p>Case presentation</p> <p>A 51 year old male developed hypercalcemia, arthralgia and B-symptoms after explantation of his kidney graft because of suspected acute rejection. The removed kidney showed vasculopathy and tubulointerstitial nephritis, which had not been overt in the biopsy taken half a year earlier. Despite explantation and withdrawal of the immunosuppression the patient's general condition deteriorated progressively. A rapid rise in serum calcium finally provoked us to check for sarcoidosis. CT scans of the lungs, broncho-alveolar-lavage and further lab tests confirmed the diagnosis.</p> <p>Conclusion</p> <p>This case demonstrates that withdrawal of immunosuppressive drugs sometimes unmasks sarcoidosis. It should be considered as differential diagnosis even in hemodialysis patients, in whom other reasons for hypercalcemia are much more common.</p

Mycobacterium tuberculosis Rv3586 (DacA) Is a Diadenylate Cyclase That Converts ATP or ADP into c-di-AMP

Cyclic diguanosine monophosphate (c-di-GMP) and cyclic diadenosine monophosphate (c-di-AMP) are recently identified signaling molecules. c-di-GMP has been shown to play important roles in bacterial pathogenesis, whereas information about c-di-AMP remains very limited. Mycobacterium tuberculosis Rv3586 (DacA), which is an ortholog of Bacillus subtilis DisA, is a putative diadenylate cyclase. In this study, we determined the enzymatic activity of DacA in vitro using high-performance liquid chromatography (HPLC), mass spectrometry (MS) and thin layer chromatography (TLC). Our results showed that DacA was mainly a diadenylate cyclase, which resembles DisA. In addition, DacA also exhibited residual ATPase and ADPase in vitro. Among the potential substrates tested, DacA was able to utilize both ATP and ADP, but not AMP, pApA, c-di-AMP or GTP. By using gel filtration and analytical ultracentrifugation, we further demonstrated that DacA existed as an octamer, with the N-terminal domain contributing to tetramerization and the C-terminal domain providing additional dimerization. Both the N-terminal and the C-terminal domains were essential for the DacA's enzymatically active conformation. The diadenylate cyclase activity of DacA was dependent on divalent metal ions such as Mg2+, Mn2+ or Co2+. DacA was more active at a basic pH rather than at an acidic pH. The conserved RHR motif in DacA was essential for interacting with ATP, and mutation of this motif to AAA completely abolished DacA's diadenylate cyclase activity. These results provide the molecular basis for designating DacA as a diadenylate cyclase. Our future studies will explore the biological function of this enzyme in M. tuberculosis

Systematically missing confounders in individual participant data meta-analysis of observational cohort studies.

One difficulty in performing meta-analyses of observational cohort studies is that the availability of confounders may vary between cohorts, so that some cohorts provide fully adjusted analyses while others only provide partially adjusted analyses. Commonly, analyses of the association between an exposure and disease either are restricted to cohorts with full confounder information, or use all cohorts but do not fully adjust for confounding. We propose using a bivariate random-effects meta-analysis model to use information from all available cohorts while still adjusting for all the potential confounders. Our method uses both the fully adjusted and the partially adjusted estimated effects in the cohorts with full confounder information, together with an estimate of their within-cohort correlation. The method is applied to estimate the association between fibrinogen level and coronary heart disease incidence using data from 154,012 participants in 31 cohort

Influence of Calendar Period on the Association Between BMI and Coronary Heart Disease: A Meta-Analysis of 31 Cohorts

Objective: The association between obesity and coronary heart disease (CHD) may have changed over time, for example due to improved pharmacological treatment of CHD risk factors. This meta-analysis of 31 prospective cohort studies explores the influence of calendar period on CHD risk associated with body mass index (BMI). Design and Methods: The relative risks (RRs) of CHD for a five-BMI-unit increment and BMI categories were pooled by means of random effects models. Meta-regression analysis was used to examine the influence of calendar period (>1985 v 1985) in univariate and multivariate analyses (including mean population age as a covariate). Results: The age, sex, and smoking adjusted RR (95% confidence intervals) of CHD for a five-BMI-unit increment was 1.28(1.22:1.34). For underweight, overweight and obesity, the RRs (compared to normal weight) were 1.11(0.91:1.36), 1.31(1.22:1.41), and 1.78(1.55:2.04), respectively. The univariate analysis indicated 31% (95%CI: 56:0) lower RR of CHD associated with a five-BMI-unit increment and a 51% (95%CI: 78: 14)) lower RR associated with obesity in studies starting after 1985 (n ¼ 15 and 10, respectively) compared to studies starting in or before 1985 (n ¼ 16 and 10). However, in the multivariate analysis, only mean population age was independently associated with the RRs for a five-BMI-unit increment and obesity ( 29(95%CI: 55: 5)) and 31(95%CI: 66:3), respectively) per 10-year increment in mean age). Conclusion: This study provides no consistent evidence for a difference in the association between BMI and CHD by calendar period. The mean population age seems to be the most important factor that modifies the association between the risk of CHD and BMI, in which the RR decreases with increasing age