Effect of intensified training on cognitive function, psychological state & performance in trained cyclists.

Athletes often undertake intensified training loads prior to competition with the goal of functionally overreaching for temporary performance enhancement; however, little is known about the impact of this on cognitive function. The aim of this study was to investigate the effect of intensified training induced fatigue on cognitive function, psychological state and performance in trained cyclists. Twenty-three trained male cyclists were randomly assigned to an intensified training group or a control group for two-weeks, followed by a two-week taper period. At baseline, one-week, two-weeks and post-taper, participants undertook a series of cognitive, performance, mood and recovery-stress assessments. The training intervention significantly increased training volume, load and strain by 108%, 116% and 151% respectively. Peak and mean power output on a maximal test and time trial significantly decreased by 4.8% and 9.4% following the two-week training intervention compared to baseline, in addition to a 169% change in total mood disturbance and significant disruption to recovery-stress balance. No change in any cognitive measure was observed across the study period. Following a two-week taper, performance, mood and well-being measures returned to baseline. Two weeks of intensified training resulted in overreaching as identified by performance and psychological measures. Cognitive function was not sensitive to intensified training promoting caution with its use as a measure for the early identification of overreaching.HighlightsTwo-weeks of intensified training significantly increased training volume, load and strain eliciting a state of overreaching in trained male cyclists.Intensified training caused deteriorations in physical performance but did not influence cognitive measures.Mood and recovery-stress balance were negatively affected by intensified training but recovered back to baseline following a two-week taper at a reduced training volume.A two-week taper period following two-weeks of intensified training did not result in improved physiological measures, physical performance parameters or mood above initial baseline values highlighting the need for careful consideration over the purpose, desired outcomes and necessity of intensified training on an individualised basis.

Corrigendum: Probing the early stages of shock-induced chondritic meteorite formation at the mesoscale.

This corrects the article DOI: 10.1038/srep45206.

A Systematic Review of Predictors of Reintervention After EVAR: Guidance for Risk-Stratified Surveillance.

BACKGROUND: Current surveillance protocols after endovascular aneurysm repair (EVAR) are ineffective and costly. Stratifying surveillance by individual risk of reintervention requires an understanding of the factors involved in developing post-EVAR complications. This systematic review assessed risk factors for reintervention after EVAR and proposals for stratified surveillance. METHODS: A systematic search according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed using EMBASE and MEDLINE databases to identify studies reporting on risk factors predicting reintervention after EVAR and proposals for stratified surveillance. RESULTS: Twenty-nine studies reporting on 39 898 patients met the primary inclusion criteria for reporting predictors of reintervention or aortic complications with or without suggestions for stratified surveillance. Five secondary studies described external validation of risk scores for reintervention or aortic complications. There was great heterogeneity in reporting risk factors identified at the pre-EVAR, intraoperative, and post-EVAR stages of treatment, although large preoperative abdominal aortic aneurysm diameter was the most commonly observed risk factor for reintervention after EVAR. CONCLUSION: Existing data on predictors of post-EVAR complications are generally of poor quality and largely derived from retrospective studies. Few studies describing suggestions for stratified surveillance have been subjected to external validation. There is a need to refine risk prediction for EVAR failure and to conduct prospective comparative studies of personalized surveillance with standard practice.

Probing the early stages of shock-induced chondritic meteorite formation at the mesoscale.

Chondritic meteorites are fragments of asteroids, the building blocks of planets, that retain a record of primordial processes. Important in their early evolution was impact-driven lithification, where a porous mixture of millimetre-scale chondrule inclusions and sub-micrometre dust was compacted into rock. In this Article, the shock compression of analogue precursor chondrite material was probed using state of the art dynamic X-ray radiography. Spatially-resolved shock and particle velocities, and shock front thicknesses were extracted directly from the radiographs, representing a greatly enhanced scope of data than could be measured in surface-based studies. A statistical interpretation of the measured velocities showed that mean values were in good agreement with those predicted using continuum-level modelling and mixture theory. However, the distribution and evolution of wave velocities and wavefront thicknesses were observed to be intimately linked to the mesoscopic structure of the sample. This Article provides the first detailed experimental insight into the distribution of extreme states within a shocked powder mixture, and represents the first mesoscopic validation of leading theories concerning the variation in extreme pressure-temperature states during the formation of primordial planetary bodies.

Microvascular disease and risk of cardiovascular events among individuals with type 2 diabetes: a population-level cohort study.

BACKGROUND: Diabetes confers a two times excess risk of cardiovascular disease, yet predicting individual risk remains challenging. The effect of total microvascular disease burden on cardiovascular disease risk among individuals with diabetes is unknown. METHODS: A population-based cohort of patients with type 2 diabetes from the UK Clinical Practice Research Datalink was studied (n=49 027). We used multivariable Cox models to estimate hazard ratios (HRs) for the primary outcome (the time to first major cardiovascular event, which was a composite of cardiovascular death, non-fatal myocardial infarction, or non-fatal ischaemic stroke) associated with cumulative burden of retinopathy, nephropathy, and peripheral neuropathy among individuals with no history of cardiovascular disease at baseline. FINDINGS: During a median follow-up of 5·5 years, 2822 (5·8%) individuals experienced a primary outcome. After adjustment for established risk factors, significant associations were observed for the primary outcome individually for retinopathy (HR 1·39, 95% CI 1·09-1·76), peripheral neuropathy (1·40, 1·19-1·66), and nephropathy (1·35, 1·15-1·58). For individuals with one, two, or three microvascular disease states versus none, the multivariable-adjusted HRs for the primary outcome were 1·32 (95% CI 1·16-1·50), 1·62 (1·42-1·85), and 1·99 (1·70-2·34), respectively. For the primary outcome, measures of risk discrimination showed significant improvement when microvascular disease burden was added to models. In the overall cohort, the net reclassification index for USA and UK guideline risk strata were 0·036 (95% CI 0·017-0·055, p<0·0001) and 0·038 (0·013-0·060, p<0·0001), respectively. INTERPRETATION: The cumulative burden of microvascular disease significantly affects the risk of future cardiovascular disease among individuals with type 2 diabetes. Given the prevalence of diabetes globally, further work to understand the mechanisms behind this association and strategies to mitigate this excess risk are warranted. FUNDING: Circulation Foundation.

Endovascular aneurysm sealing for the treatment of ruptured abdominal aortic aneurysms.

PURPOSE: To assess the feasibility and report preliminary results of ruptured abdominal aortic aneurysm (rAAA) repair with endovascular aneurysm sealing (EVAS), a novel therapeutic alternative whose feasibility has not been established in rAAAs due to the unknown effects of the rupture site on the ability to achieve sealing. CASE REPORT: Between December 2013 and April 2014, 5 patients (median age 71 years, range 57-90; 3 men) with rAAAs were treated with the Nellix EVAS system at a single institution. Median aneurysm diameter was 70 mm (range 67-91). Aneurysm morphology in 4 of the 5 patients was noncompliant with instructions for use (IFU) for both EVAS and standard stent-grafts; the remaining patient was outside the IFU for standard stent-grafts but treated with EVAS under standard IFU for the Nellix system. Median Hardman index was 2 (range 0-3). Two patients died of multiorgan failure after re-laparotomy and intraoperative cardiac arrest, respectively. Among survivors, all devices were patent with no signs of endoleak or failed aneurysm sac sealing at 6 months (median follow-up 9.2 months). CONCLUSION: EVAS for the management of infrarenal rAAAs appears feasible. The use of EVAS in emergency repairs may broaden the selection criteria of the current endovascular strategy to include patients with more complex aneurysm morphology.

Peripheral neuropathy and the risk of cardiovascular events in type 2 diabetes mellitus.

AIMS: Identifying individuals with diabetes at high risk of cardiovascular disease (CVD) remains challenging. We aimed to establish whether peripheral neuropathy (PN) is associated with incident CVD events and to what extent information on PN may improve risk prediction among individuals with type 2 diabetes. METHODS: We obtained data for individuals with type 2 diabetes, and free of CVD, from a large primary care patient cohort. Incident CVD events were recorded during a 30-month follow-up period. Eligible individuals had complete ascertainment of cardiovascular risk factors and PN status at baseline. The association between PN and incident CVD events (non-fatal myocardial infarction, coronary revascularisation, congestive cardiac failure, transient ischaemic attack and stroke) was evaluated using Cox regression, adjusted for standard CVD risk factors. We assessed the predictive accuracy of models including conventional CVD risk factors with and without information on PN. RESULTS: Among 13 043 eligible individuals, we recorded 407 deaths from any cause and 399 non-fatal CVD events. After adjustment for age, sex, ethnicity, systolic blood pressure, cholesterol, body mass index, HbA1c, smoking status and use of statin or antihypertensive medication, PN was associated with incident CVD events (HR 1.33; 95% CI 1.02 to 1.75, p=0.04). The addition of information on PN to a model based on standard CVD risk factors resulted in modest improvements in discrimination for CVD risk prediction and reclassified 6.9% of individuals into different risk categories. CONCLUSIONS: PN is associated with increased risk for a first cardiovascular event among individuals with diabetes.

Influence of foot ulceration on cause-specific mortality in patients with diabetes mellitus.

OBJECTIVE: The purpose of this study was to assess the odds of all-cause mortality in individuals with diabetic foot ulceration (DFU) compared with those with diabetes and no history of DFU. In addition, we sought to determine the strength of association of DFU with cardiovascular and nonvascular mortality. METHODS: We obtained data for a cohort of patients who attended a secondary care diabetic foot clinic or a general diabetes clinic between 2009 and 2010. A clinic cohort of patients with diabetes and no history of DFU provided a control group. Cause-specific mortality was recorded during a median follow-up duration of 3.6 years (interquartile range, 3.3-4.2 years). The association between DFU and all-cause mortality was evaluated by Cox regression. The association between DFU and cardiovascular mortality was determined by competing risk modeling. RESULTS: We recorded 145 events of all-cause mortality and 27 events of cardiovascular mortality among 869 patients with diabetes. After adjustment for potential confounders, DFU was associated with both cardiovascular disease (hazard ratio, 2.53; 95% confidence interval, 0.98-6.49; P = .05) and all-cause mortality (hazard ratio, 3.98; 95% confidence interval, 2.55-6.21; P < .001). The proportion of deaths attributable to cardiovascular disease was similar between the groups (18% with diabetes only and 19% with DFU; P = .91). CONCLUSIONS: DFU is associated with premature death from vascular and nonvascular causes.

Comparison of Campylobacter jejuni PFGE and Penner subtypes in human infections and in water samples from the Taieri River catchment of New Zealand.

AIMS: To determine the degree of overlap in strain types of Campylobacter jejuni isolated from clinical cases and water samples from the Taieri catchment in the South Island of New Zealand. METHODS AND RESULTS: Thermophilic Campylobacter were collected from human cases of infection, the main stem of the Taieri River and streams within distinct land-use types over a 1-year period. Campylobacter jejuni (187 isolates) and Campylobacter lari (four isolates) were identified using a multiplex polymerase chain reaction protocol. Isolates were typed by the Penner method and pulsed-field gel electrophoresis (PFGE) utilizing two restriction endonucleases. Several serotypes and PFGE types occurred in both water samples and clinical cases when the restriction profiles for each enzyme were considered separately. However, when PFGE profiles and serotyping were combined, there was no overlap between Camp. jejuni types from water and clinical cases. CONCLUSIONS: The results of this study indicate that recreational water in the Taieri catchment is not a major source of campylobacteriosis in the Dunedin area. SIGNIFICANCE AND IMPACT OF THE STUDY: This study suggests the risk of acquiring campylobacteriosis from surface waters in the Taieri catchment is considerably lower than previously predicted and highlights the necessity of using two endonucleases in PFGE typing.

Application of the comet and micronucleus assays to the detection of B[a]P genotoxicity in haemocytes of the green-lipped mussel (Perna viridis).

Green-lipped mussels (Perna viridis) were exposed to water-borne benzo[a]pyrene (B[a]P) at nominal concentrations of 0, 0.3, 3 and 30 microg l(-1) for up to 12 days, and both the relative levels of DNA strand breaks (assessed using an alkaline comet assay) and the proportion of micronucleus (MN) formation were monitored in mussel haemocytes at days 0, 1, 3, 6 and 12. The results of the comet assay indicated that an increase in the proportion of strand breaks occurred generally with increasing B[a]P concentration, but a significant decrease in the levels of DNA damage was observed after exposure for 12 days at all concentrations tested, suggesting that the patterns of changes in the levels of DNA strand breakage can be explained by the threshold dependent DNA repair theory. Moreover, the relatively slow development and recovery of the DNA damage response in mussel haemocytes in comparison with previous findings utilizing P. viridis hepatopancreas suggests that the response of DNA alteration upon exposure to B[a]P may be tissue-specific in this species. Monitoring the frequency of micronucleus development in mussel haemocytes indicated both dose- and time-response relationships within the exposure period. Furthermore, the levels of DNA strand breakage correlated well with the levels of micronucleus induction, suggesting a possible cause and effect relationship between the two damage types. We suggest that DNA strand breakage and micronucleus formation in mussel haemocytes can potentially be used as convenient biomarkers of exposure to genotoxicants in the marine environment.

Structure-function relationships in the tryptophan-rich, antimicrobial peptide indolicidin.

Indolicidin is a cationic 13 amino acid peptide amide produced in the granules of bovine neutrophils with the sequence H-ILPWKWPWWPWRR-NH2. Indolicidin is both antimicrobial and, to a lesser extent, haemolytic. In order to systematically investigate structure-function relationships, the solid-phase synthesis of indolicidin and 48 distinct analogues are reported, as well as the characterization of their respective biological properties. Peptides synthesized and characterized include analogues with modified terminal functions, truncations from either terminus, an alanine scan to determine the role of each individual amino acid, specific amino acid exchanges of aromatic, charged and structural residues and several retro-, inverso- and retroinverso-analogues. Together, characterization of these analogues identifies specific residues involved in antimicrobial or haemolytic activity and suggests a core structure that may form a scaffold for the further development of peptidomimetic analogues of indolicidin.

Streptocidins A-D, novel cyclic decapeptide antibiotics produced by Streptomyces sp. Tü 6071. II. Structure elucidation.

The structures of the new antibiotics streptocidins A approximately D were elucidated as cyclic decapeptides cyclo[L-Val1-L-Orn2-L-Leu3-D-Phe4-L-Pro5-L-Leu6-X7-L-Asn8-L-Gln9-X10] with X7=D-Trp (A, B, C) or D-Phe (D) and X10=L-Tyr (A), L-Trp (B, D), or D-Trp (C). The amino acid composition (including the configuration) of the substances was determined by chiral-phase GC-MS of the hydrolysates. The sequences were established by EDMAN degradation following linearisation of the cyclic peptides upon treatment with LiAlH4. NMR spectroscopic studies of streptocidins C and D confirmed the proposed sequences and provided conformational data which indicate a molecular topology of streptocidins C and D similar to those of tyrocidine A and gramicidin S.

Staphylococcus aureus resistance to human defensins and evasion of neutrophil killing via the novel virulence factor MprF is based on modification of membrane lipids with l-lysine.

Defensins, antimicrobial peptides of the innate immune system, protect human mucosal epithelia and skin against microbial infections and are produced in large amounts by neutrophils. The bacterial pathogen Staphylococcus aureus is insensitive to defensins by virtue of an unknown resistance mechanism. We describe a novel staphylococcal gene, mprF, which determines resistance to several host defense peptides such as defensins and protegrins. An mprF mutant strain was killed considerably faster by human neutrophils and exhibited attenuated virulence in mice, indicating a key role for defensin resistance in the pathogenicity of S. aureus. Analysis of membrane lipids demonstrated that the mprF mutant no longer modifies phosphatidylglycerol with l-lysine. As this unusual modification leads to a reduced negative charge of the membrane surface, MprF-mediated peptide resistance is most likely based on repulsion of the cationic peptides. Accordingly, inactivation of mprF led to increased binding of antimicrobial peptides by the bacteria. MprF has no similarity with genes of known function, but related genes were identified in the genomes of several pathogens including Mycobacterium tuberculosis, Pseudomonas aeruginosa, and Enterococcus faecalis. MprF thus constitutes a novel virulence factor, which may be of general relevance for bacterial pathogens and represents a new target for attacking multidrug resistant bacteria.

Combinatorial peptide libraries reveal the ligand-binding mechanism of the oligopeptide receptor OppA of Lactococcus lactis.

The oligopeptide transport system (Opp) of Lactococcus lactis has the unique capacity to mediate the transport of peptides from 4 up to at least 18 residues. The substrate specificity of this binding protein-dependent ATP-binding cassette transporter is determined mainly by the receptor protein OppA. To study the specificity and ligand-binding mechanism of OppA, the following strategy was used: (i) OppA was purified and anchored via the lipid moiety to the surface of liposomes; (ii) the proteoliposomes were used in a rapid filtration-based binding assay with radiolabeled nonameric bradykinin as a reporter peptide; and (iii) combinatorial peptide libraries were used to determine the specificity and selectivity of OppA. The studies show that (i) OppA is able to bind peptides up to at least 35 residues, but there is a clear optimum in affinity for nonameric peptides; (ii) the specificity for nonameric peptides is not equally distributed over the whole peptide, because positions 4, 5, and 6 in the binding site are more selective; and (iii) the differences in affinity for given side chains is relatively small, but overall hydrophobic residues are favored-whereas glycine, proline, and negatively charged residues lower the binding affinity. The data indicate that not only the first six residues (enclosed by the protein) but also the C-terminal three residues interact in a nonopportunistic manner with (the surface of) OppA. This binding mechanism is different from the one generally accepted for receptors of ATP-binding cassette-transporter systems.

Lantibiotics and microcins: polypeptides with unusual chemical diversity.

Bacterial-derived antimicrobial polypeptides enjoy a large degree of structural and chemical diversity. Two well-studied examples of such polypeptides are the lanthionine-containing lantibiotics produced by a variety of Gram-positive bacteria, and their Gram-negative counterparts, the microcins. Both groups are produced as gene-encoded precursor peptides and undergo post-translational modification to generate the active moieties. Structure elucidation of novel lantibiotics and microcins has recently uncovered further novel structural and chemical features and, combined with the generation of analogue peptides by genetic manipulation, new insights into structure-function relationships have been gained. Furthermore, study of the mode of action of the lantibiotics nisin and mersacidin has revealed their use of a 'docking molecule' in the target cell to facilitate their biological activities. Meanwhile, in vitro studies with microcin B17 have helped to uncover the molecular mechanisms by which post-translational modification results in the formation of heterocyclic oxazole and thiazole rings. From a practical standpoint, both groups of polypeptides represent new lead structures for future development of antimicrobial agents, whilst the identification of the 'docking molecules' represents a step forward in the search for novel targets for future antibiosis.

Inducible expression and cellular location of AgrB, a protein involved in the maturation of the staphylococcal quorum-sensing pheromone.

AgrB has been suggested to be responsible for the posttranslational modification in staphylococci that leads to the production of the thiolactone-containing agr peptide pheromone. We demonstrate that AgrB is located in the cytoplasmic membrane. Vectors were constructed for the xylose-inducible overexpression of agrB, and of agrB and agrD together. A Staphylococcus epidermidis strain deleted for agr and containing these vectors was assayed for AgrB protein and pheromone production. The lack of adequate pheromone production suggests the involvement of additional factors in the production of the agr pheromone.

Extensive post-translational modification, including serine to D-alanine conversion, in the two-component lantibiotic, lacticin 3147.

Lacticin 3147 is a two-component bacteriocin produced by Lactococcus lactis subspecies lactis DPC3147. In order to further characterize the biochemical nature of the bacteriocin, both peptides were isolated which together are responsible for the antimicrobial activity. The first, LtnA1, is a 3,322 Da 30-amino acid peptide and the second component, LtnA2, is a 29-amino acid peptide with a mass of 2,847 Da. Conventional amino acid analysis revealed that both peptides contain the thioether amino acid, lanthionine, as well as an excess of alanine to that predicted from the genetic sequence of the peptides. Chiral phase gas chromatography coupled with mass spectrometry of amino acid composition indicated that both LtnA1 and LtnA2 contain D-alanine residues and amino acid sequence analysis of LtnA1 confirmed that the D-alanine results from post-translational modification of a serine residue in the primary translation product. Taken together, these results demonstrate that lacticin 3147 is a novel, two-component, D-alanine containing lantibiotic that undergoes extensive post-translational modification which may account for its potent antimicrobial activity against a wide range of Gram-positive bacteria.

H-2 class I knockout, HLA-A2.1-transgenic mice: a versatile animal model for preclinical evaluation of antitumor immunotherapeutic strategies.

H-2 class I-negative, HLA-A2.1-transgenic HHD mice were used for a comparative evaluation of the immunogenicity of HLA-A2.1-restricted human tumor-associated cytotoxic T lymphocyte (CTL) epitopes. A hierarchy was established among these peptides injected into mice in incomplete Freund's adjuvant which correlates globally with their capacity to bind and stabilize HLA-A2.1 molecules. Co-injection of a helper peptide enhanced most CTL responses. In contrast, classical HLA class I-transgenic mice which still express their own class I molecules did not, in most cases, develop HLA-A2.1-restricted CTL responses under the same experimental conditions. Different monoepitope immunization strategies of acceptable clinical usage were compared in HHD mice. Recombinant Ty-virus-like particles, or DNA encoding epitopes fused to the hepatitis B virus middle envelope protein gave the best results. Using this latter approach and a melanoma-based polyepitope construct, CTL responses against five distinct epitopes could be elicited simultaneously in a single animal. Thus, HHD mice provide a versatile animal model for preclinical evaluation of peptide-based cancer immunotherapy.

Inactivation of the dlt operon in Staphylococcus aureus confers sensitivity to defensins, protegrins, and other antimicrobial peptides.

Positively charged antimicrobial peptides with membrane-damaging activity are produced by animals and humans as components of their innate immunity against bacterial infections and also by many bacteria to inhibit competing microorganisms. Staphylococcus aureus and Staphylococcus xylosus, which tolerate high concentrations of several antimicrobial peptides, were mutagenized to identify genes responsible for this insensitivity. Several mutants with increased sensitivity were obtained, which exhibited an altered structure of teichoic acids, major components of the Gram-positive cell wall. The mutant teichoic acids lacked D-alanine, as a result of which the cells carried an increased negative surface charge. The mutant cells bound fewer anionic, but more positively charged proteins. They were sensitive to human defensin HNP1-3, animal-derived protegrins, tachyplesins, and magainin II, and to the bacteria-derived peptides gallidermin and nisin. The mutated genes shared sequence similarity with the dlt genes involved in the transfer of D-alanine into teichoic acids from other Gram-positive bacteria. Wild-type strains bearing additional copies of the dlt operon produced teichoic acids with higher amounts of D-alanine esters, bound cationic proteins less effectively and were less sensitive to antimicrobial peptides. We propose a role of the D-alanine-esterified teichoic acids which occur in many pathogenic bacteria in the protection against human and animal defense systems.