Cancer blues? A promising judgment bias task indicates pessimism in nude mice with tumors

In humans, affective states can bias responses to ambiguous information: a phenomenon termed judgment bias (JB). Judgment biases have great potential for assessing affective states in animals, in both animal welfare and biomedical research. New animal JB tasks require construct validation, but for laboratory mice (Mus musculus), the most common research vertebrate, a valid JB task has proved elusive. Here (Experiment 1), we demonstrate construct validity for a novel mouse JB test: an olfactory Go/Go task in which subjects dig for high- or low-value food rewards. In C57BL/6 and Balb/c mice faced with ambiguous cues, latencies to dig were sensitive to high/low welfare housing: environmentally-enriched animals responded with relative 'optimism' through shorter latencies. Illustrating the versatility of this validated JB task across different fields of research, it further allowed us to test hypotheses about the mood-altering effects of cancer in male and female nude mice (Experiment 2). Males, although not females, treated ambiguous cues as intermediate; and males bearing subcutaneous lung adenocarcinomas also responded more pessimistically to these than did healthy controls. To our knowledge, this is the first evidence of a valid mouse JB task, and the first demonstration of pessimism in tumor-bearing animals. This task still needs to be refined to improve its sensitivity. However, it has great potential for investigating mouse welfare, the links between affective state and disease, depression-like states in animals, and hypotheses regarding the neurobiological mechanisms that underlie affect-mediated biases in judgment.

Maternal effects obscure condition-dependent sex allocation in changing environments

Climate change increases environmental fluctuations which thereby impact population demography. Species with temperature-dependent sex determination may experience more extreme sex ratio skews, but this has not been considered in species with chromosomally determined sex. However, anticipatory maternal effects cause lifelong physiological changes impacting sex ratios. Here we show, in mice, that more sons were born to mothers in good condition when their breeding environment matched their gestational environment, consistent with theoretical predictions, but mothers in mismatched environments have no condition-sex ratio relationship. Thus, the predicted effect of condition on sex ratio was obscured by maternal effects when the environment changed. This may explain extreme sex ratio skews in reintroduced or translocated populations, and sex ratio skews may become more common and less predictable with accelerating environmental change.

Time perception, pacing and exercise intensity: maximal exercise distorts the perception of time

INTRODUCTION

Currently there are no data examining the impact of exercise on the perception of time, which is surprising as optimal competitive performance is dependent on accurate pacing using knowledge of time elapsed.

METHODS

With institutional ethics approval, 12 recreationally active adult participants (f=7, m=5) undertook both 30s Wingate cycles and 20min (1200s) rowing ergometer bouts as short and long duration self-paced exercise trials, in each of three conditions on separate occasions: 1) light exertion: RPE 11, 2) heavy exertion: RPE 15, 3) maximal exertion: RPE 20. Participants were unaware of exercise duration and were required to verbally indicate when they perceived (subjective time) 1) 25%, 2) 50%, 3) 75% and 4) 100% of each bout's measured (chronological) time had elapsed.

RESULTS

In response to the Wingate task, there was no difference between durations of subjective time at the 25%, nor at the 50% interval. However, at the 75% and 100% intervals, the estimate for the RPE 20 condition was shortest (P<0.01). In response to rowing, there were no differences at the 25% interval, but there was some evidence that the RPE 20 condition was perceived shorter at 50%. At 75% and 100%, the RPE 20 condition was perceived to be shorter than both RPE 15 (P=0.04) and RPE 11 (P=0.008) conditions.

CONCLUSION

This study is the first to empirically demonstrate that exercise intensity distorts time perception, particularly during maximal exercise. Consequently external feedback of chronological time may be an important factor for athletes undertaking maximal effort tasks or competitions.

Cryptic male choice: experimental evidence of sperm sex ratio and seminal fluid adjustment in relation to coital rate

The differential allocation hypothesis suggests that a mother should adjust the sex of offspring in relation to her mate’s attractiveness, thereby increasing future reproductive fitness when her sons inherit the attractive traits. More attractive males have been shown to sire more sons, but it is possible that the sex ratio skew could be a result of paternal rather than maternal manipulation, which would be a more parsimonious explanation. We manipulated coital rate (an indicator of attractiveness) in laboratory mice and showed that males that mate more often have higher levels of glucose in their semen despite lower blood glucose levels. Since peri-conceptual glucose levels in utero increase male conceptus survival, this could result in male-biased sex ratios. The males that mated most also had more remaining X-chromosome-bearing-spermatozoa, suggesting depletion of Y-chromosome-bearing-spermatozoa during mating. We hypothesise that males may alter both seminal fluids and X : Y ratios in an ejaculate to influence subsequent sex ratios. Our results further support a paternal role in sex allocation.

Efficacy of inspiratory muscle training as a practical and minimally intrusive technique to aid functional fitness among adults with obesity

OBJECTIVE

To examine the efficacy of inspiratory muscle training (IMT) as a non-intrusive and practical intervention to stimulate improved functional fitness in adults with obesity. As excess adiposity of the chest impedes the mechanics of breathing, targeted re-training of the inspiratory muscles may ameliorate sensations of breathlessness, improve physical performance and lead to greater engagement in physical activity.

METHODS

Sixty seven adults (BMI=36±6.5) were randomized into either an experimental (EXP: n=35) or placebo (PLA: n=32) group with both groups undertaking a 4-week IMT intervention, comprising daily use of a inspiratory resistance device set to 55% (EXP), or 10% (PLA) of maximum inspiratory effort.

RESULTS

Inspiratory muscle strength was significantly improved in EXP (19.1 cmH₂0 gain; P<0.01) but did not change in PLA. Additionally, the post training walking distance covered was significantly extended for EXP (P<0.01), but not for PLA. Bivariate analysis demonstrated a positive association between the change (%) of performance in the walking test and BMI (r=0.78; P<0.01) for EXP.

CONCLUSION

The findings from this study suggest IMT provides a practical, self-administered intervention for use in a home setting. This could be a useful strategy to improve the functional fitness of obese adults and perhaps lead to better preparedness for engagement in physical activity initiatives.

Gestational experience alters sex allocation in the subsequent generation

Empirical tests of adaptive maternal sex allocation hypotheses have presented inconsistent results in mammals. The possibility that mothers are constrained in their ability to adjust sex ratios could explain some of the remaining variation. Maternal effects, the influence of the maternal phenotype or genotype on her developing offspring, may constrain sex allocation through physiological changes in response to the gestational environment. We tested if maternal effects constrain future parental sex allocation through a lowered gestational stress environment in laboratory mice. Females that experienced lowered stress as embryos in utero gave birth to female-biased litters as adults, with no change to litter size. Changes in offspring sex ratio was linked to peri-conceptual glucose, as those females that had increasing blood glucose peri-conceptionally gave birth to litters with a higher male to female sex ratio. There was, however, no effect of the lowered prenatal stress for developing male embryos and their sperm sex ratio when adult. We discuss the implications of maternal effects and maternal stress environment on the lifelong physiology of the offspring, particularly as a constraint on later maternal sex allocation.

Brain and Cardiorespiratory Responses to Exercise in Hot and Thermoneutral Conditions

The aim of this study was to test whether or not concurrent evaluations of brain (electroencephalography [EEG]) and cardiorespiratory responses to exercise are influenced by environmental conditions. 10 adult male participants performed a standardized incremental exercise test to exhaustion on a cycle ergometer in an environment controlled laboratory on 2 separate occasions, in a randomized order; one in a hot condition (34.5°C) and one in a thermoneutral condition (20°C). EEG, heart rate and expired air were collected throughout. EEG data were decontaminated for artefacts, log-transformed and expressed as aggregated alpha and beta power responses across electrodes reflecting the frontal cortex of the brain. Performance outcomes showed there was no difference in  V˙O2 peak across hot (42.5 ml/kg/min) and neutral (42.8 ml/kg/min) conditions, although ventilatory threshold (VT) occurred at a lower threshold (68%) in hot compared to neutral condition (74%) (p<0.05). EEG alpha and beta wave responses both demonstrated significant increases from baseline to VT (p<0.01). EEG beta-band activity was significantly elevated in the heat compared to the neutral condition. In conclusion, elevated EEG beta-band activity in response to incremental exercise in the heat suggests that beta-band activation and cortical awareness increases as exercise becomes increasingly intense.

Utility of field-based techniques to assess Indigenous Australians' functional fitness and sedentary time

OBJECTIVE

To examine the utility of field-based techniques to assess functional exercise capacity and sedentary time in Indigenous and non-Indigenous regional Australian adults.

STUDY DESIGN

Observational, analytic cohort study.

METHODS

Ninety six adults residing in regional and remote Australian communities participated in this study (Indigenous n = 61 and non-Indigenous Australians n = 35). Participants undertook a field-based test of functional exercise capacity (6 min walk test; 6 MWT) and wore an accelerometer during waking hours for seven days, provided self-report data on physical activity and sedentary time and rated experiences in regard to the ease of complying with study protocols.

RESULTS

There were high levels of compliance in this study (Indigenous: 91% and non-Indigenous: 97%). Functional exercise capacity was lower in Indigenous Australians (P < 0.001), and independently associated with advancing age, higher BMI, and indigeneity, with 45% of variability in the 6 MWT distance explained by these factors. The relationship between accelerometer and self-report measures of sedentary behaviour was significant (P < 0.001) but only explained 17% of the total variation.

CONCLUSIONS

This study demonstrated very good compliance for the methods utilised and is the first to report reduced functional exercise capacity in Indigenous people.

IMPLICATIONS

The field-based techniques from this study demonstrate good utility for larger scale implementation in regional Indigenous populations.

Utilization of a high-throughput shoot imaging system to examine the dynamic phenotypic responses of a C4 cereal crop plant to nitrogen and water deficiency over time

The use of high-throughput phenotyping systems and non-destructive imaging is widely regarded as a key technology allowing scientists and breeders to develop crops with the ability to perform well under diverse environmental conditions. However, many of these phenotyping studies have been optimized using the model plant Arabidopsis thaliana. In this study, The Plant Accelerator(®) at The University of Adelaide, Australia, was used to investigate the growth and phenotypic response of the important cereal crop, Sorghum bicolor L. Moench and related hybrids to water-limited conditions and different levels of fertilizer. Imaging in different spectral ranges was used to monitor plant composition, chlorophyll, and moisture content. Phenotypic image analysis accurately measured plant biomass. The data set obtained enabled the responses of the different sorghum varieties to the experimental treatments to be differentiated and modelled. Plant architectural instead of architecture elements were determined using imaging and found to correlate with an improved tolerance to stress, for example diurnal leaf curling and leaf area index. Analysis of colour images revealed that leaf 'greenness' correlated with foliar nitrogen and chlorophyll, while near infrared reflectance (NIR) analysis was a good predictor of water content and leaf thickness, and correlated with plant moisture content. It is shown that imaging sorghum using a high-throughput system can accurately identify and differentiate between growth and specific phenotypic traits. R scripts for robust, parsimonious models are provided to allow other users of phenomic imaging systems to extract useful data readily, and thus relieve a bottleneck in phenotypic screening of multiple genotypes of key crop plants.

Self-reported health behaviour change in adults: analysis of the Canadian Community Health Survey 4.1

Introduction

Knowledge of Canadians' experiences in making health behaviour changes (HBCs) in general, and among those at risk due to body mass index (BMI), would help inform health promotion / disease prevention programs. Selected self reported HBCs in the past 12 months by BMI category were examined in this secondary analysis of the Canadian Community Health Survey 4.1. These HBCs included increased sports/exercise, weight loss and improved eating habits. Barriers to HBC were also examined.

Methods

Descriptive analyses and forward stepwise logistic regression were completed on data from respondents 18 years and older. Self-reported BMI was corrected by the method of Connor Gorber et al. (2008).

Results

Our final sample was n = 111 449. Overall, 58% of respondents had made an HBC, with increased sports/exercise as the most important HBC in 29% of the sample, followed by improved eating habits (10%) and weight loss (7%). Half (51%) experienced barriers to HBC; lack of will power was most commonly cited, followed by work and family responsibilities. Obese respondents reported HBC more frequently than normal-weight respondents (60% vs. 55%), but the prevalence of increased sports/ exercise and improved eating habits was similar across BMI categories. Regression models accounted for only 6%-10% of the total variance.

Conclusion

That a majority of respondents had made at least one HBC bodes well for positively shifting population health. Additional work to further characterize the population, and to improve on population indicators, is needed to assess the impact of health promotion/disease prevention efforts. These findings provide important first population benchmarks for future work.

Self-reported health behaviour change in adults: analysis of the Canadian Community Health Survey 4.1

INTRODUCTION

Knowledge of Canadians' experiences in making health behaviour changes (HBCs) in general, and among those at risk due to body mass index (BMI), would help inform health promotion / disease prevention programs. Selected self reported HBCs in the past 12 months by BMI category were examined in this secondary analysis of the Canadian Community Health Survey 4.1. These HBCs included increased sports/exercise, weight loss and improved eating habits. Barriers to HBC were also examined.

METHODS

Descriptive analyses and forward stepwise logistic regression were completed on data from respondents 18 years and older. Self-reported BMI was corrected by the method of Connor Gorber et al. (2008).

RESULTS

Our final sample was n = 111 449. Overall, 58% of respondents had made an HBC, with increased sports/exercise as the most important HBC in 29% of the sample, followed by improved eating habits (10%) and weight loss (7%). Half (51%) experienced barriers to HBC; lack of will power was most commonly cited, followed by work and family responsibilities. Obese respondents reported HBC more frequently than normal-weight respondents (60% vs. 55%), but the prevalence of increased sports/ exercise and improved eating habits was similar across BMI categories. Regression models accounted for only 6%-10% of the total variance.

CONCLUSION

That a majority of respondents had made at least one HBC bodes well for positively shifting population health. Additional work to further characterize the population, and to improve on population indicators, is needed to assess the impact of health promotion/disease prevention efforts. These findings provide important first population benchmarks for future work.

Pacing and awareness: brain regulation of physical activity

The aim of this current opinion article is to provide a contemporary perspective on the role of brain regulatory control of paced performances in response to exercise challenges. There has been considerable recent conjecture as to the role of the brain during exercise, and it is now broadly accepted that fatigue does not occur without brain involvement and that all voluntary activity is likely to be paced at some level by the brain according to individualised priorities and knowledge of personal capabilities. This article examines the role of pacing in managing and distributing effort to successfully accomplish physical tasks, while extending existing theories on the role of the brain as a central controller of performance. The opinion proposed in this article is that a central regulator operates to control exercise performance but achieves this without the requirement of an intelligent central governor located in the subconscious brain. It seems likely that brain regulation operates at different levels of awareness, such that minor homeostatic challenges are addressed automatically without conscious awareness, while larger metabolic disturbances attract conscious awareness and evoke a behavioural response. This supports the view that the brain regulates exercise performance but that the interpretation of the mechanisms underlying this effect have not yet been fully elucidated.

Individual traits influence vigilance in wild female eastern grey kangaroos

Vigilance is an essential component of antipredator behaviour and is also used to monitor conspecifics, but is traded off against feeding in herbivores. This trade-off can be influenced by variation in many environmental, social and individual traits. Our aim was to test the relationship between individual-level traits, including boldness, body condition and reproductive state, and vigilance, while controlling for environmental and social variables. Using multiple 5-min video samples of 30 foraging, individually recognisable, female eastern grey kangaroos (Macropus giganteus) at Sundown National Park in Queensland, we investigated individual-level variation in the duration, intensity and target of vigilance behaviour during foraging. On separate occasions, we used flight-initiation distance tests to measure boldness in our kangaroos. Females with longer flight-initiation distances (shyer females) spent more time vigilant, providing preliminary support for studies of animal personality that have suggested that boldness may covary with vigilance. Body condition did not affect the total time spent vigilant, but females in poorer body condition spent more of their vigilance time in low-intensity vigilance. Vigilance patterns were not related to reproductive state, but varied among months and differed between mornings and afternoons, and females spent more time in high-intensity vigilance when further from cover. Even after accounting for all our variables we found that 7% of the variation in total time vigilant and 14% of the variation in vigilance intensity was explained by individual identity. This highlights the importance of individual-level variation in vigilance behaviour.

Physiological responses to self-paced exercise: effort-matched comparisons across running and rowing modalities

AIM

The purpose of this study was to examine whether or not physiological responses to self-pacing are similar across different exercise modalities where the rating of perceived exertion (RPE) is matched.

METHODS

Ten recreationally active adult male subjects completed baseline tests of peak oxygen uptake (.VO2) and subsequently on two separate occasions performed 20-min exercise bouts at RPE 15 (Hard) on both a motorized treadmill and a rowing ergometer.

RESULTS

Mean relative work intensity (% of baseline peak (.VO2) for treadmill running was significantly higher than for rowing (86.1% vs. 83.7%) (P<0.05). Mean heart rates (174.7±5.9 vs. 165.5±6.6 b∙min-1) and pre- to post-bout changes in blood lactate concentration (4.0±0.8 vs. 3.3±1.2 mmol/L) were also greater in the running trial than rowing (P<0.05). Baseline peak (.VO2 was positively correlated between modalities (r=0.63; P<0.05) as were the main trial mean (.VO2 (r=0.73; P<0.05) and heart rate (r=0.67; P<0.05) from the 20-min bouts.

CONCLUSION

The elevated relative exercise intensity and physiological responses to motorized treadmill running suggests greater work outputs can be accomplished in this modality for the same perceived effort compared to rowing among recreationally active participants.

Sport-specific fitness testing differentiates professional from amateur soccer players where VO2max and VO2 kinetics do not

AIM

The purpose of this study was to identify if sport-specific and cardiopulmonary exercise testing differentiated professional from amateur soccer players.

METHODS

Thirty six men comprising 18 professional (mean±s: age 23.2±2.4 years) and 18 amateur (mean±SD: age 21.1±1.6 years) soccer players participated and performed four tests on separate occasions: 1) a graded exercise test to determine VO2max; 2) four exercise transients from walking to 80%Δ for the determination of VO2 kinetics; 3) the Yo-Yo Intermittent Recovery Test level 2 (Yo-Yo IR2) and 4) a repeated sprint test (RST).

RESULTS

The players did not differ in VO2max (professional 56.5±2.9 mL.kg-1.min-1; amateur 55.7±3.5 mL.kg-1.min-1: P=0.484) or VO2 kinetic fundamental measures (τ1 onset, professional 24.5±3.2 s; amateur 24.0±1.8 s: τ1 cessation, professional 28.7±2.8 s; amateur 29.3±3.5 s: P=0.923). However, the amateurs were outperformed in the Yo-Yo IR2 (Professional 966±153 m; Amateur 840±156 m) (P=0.034) and RST (best time, professional 6.46±0.27 s; amateur 6.84±0.24 s, P=0.012).

CONCLUSION

Performance indices derived from field-based sport-specific performance tests identified significant differences between professional and amateur players (P<0.05). However, neither tests of VO2 kinetics nor VO2max differentiated between groups, suggesting laboratory tests of cardiorespiratory parameters are probably less consequential to soccer than sport-specific field-based observations.

Four weeks of inspiratory muscle training improves self-paced walking performance in overweight and obese adults: a randomised controlled trial

Objective. To examine whether a programme of inspiratory muscle training (IMT) improves accumulative distance of self-paced walking in overweight and obese adults. Methods. A total of 15 overweight and obese adults were randomized into experimental (EXP: n = 8) and placebo (PLA: n = 7) groups. Lung function, inspiratory muscle performance, 6-minute walking test, and predicted [Formula: see text]O(2) max were assessed prior to and following the 4-week IMT intervention. Both groups performed 30 inspiratory breaths, twice daily using a proprietary inspiratory resistance device set to 55% of baseline maximal effort (EXP), or performing the same inspiratory training procedure at the minimum resistive setting (PLA). Results. Lung function was unchanged in both groups after-training; however inspiratory muscle strength was significantly improved in EXP (19 ± 25.2 cm H(2)O gain; P < 0.01) but did not significantly change in PLA. Additionally, the posttraining distance covered in the 6-minute walking test was significantly extended for EXP (62.5 ± 37.7 m gain; P < 0.01), but not for PLA. A positive association was observed between the change (%) of performance gain in the 6-minute walking test and body mass index (r = 0.736; P < 0.05) for EXP. Conclusion. The present study suggests that IMT provides a practical, minimally intrusive intervention to significantly augment both inspiratory muscle performance and walking distance covered by overweight and obese adults in a clinically relevant 6-minute walk test. This indicates that IMT may provide a useful priming (preparatory) strategy prior to entry in a physical training programme for overweight and obese adults.

Molecular mechanisms of Staphylococcus aureus nasopharyngeal colonization

Staphylococcus aureus is responsible for a wide range of different infections ranging in severity from mild to fatal. However, it primarily exists as a commensal organism in a number of different anatomical sites including the nasopharynx. Although colonization itself is a harmless state, colonized individuals are at risk of endogenous infection when S. aureus enters otherwise sterile sites via wounds or indwelling medical devices. As such, studies of colonization may identify important targets for vaccines or other prophylactic approaches. Colonization is a dynamic process; S. aureus must attach to host surfaces, overcome immune components and compete with other commensal microbes. This occurs via a number of surface-attached and secreted proteins and other factors such as wall teichoic acid. In addition, colonizing S. aureus must constantly replicate to maintain its niche and exclude other strains. These myriad interactions provide a strong selective pressure for the maintenance or enhancement of mechanisms of adhesion, invasion and immune evasion. The evolutionary implications of this may explain why S. aureus is such a capable pathogen because many of the proteins involved in colonization have also been identified as virulence factors. This review describes the diverse molecular mechanisms used by S. aureus to colonize the host and discusses how the pressures that have selected for these may have led to its virulence.

Diagnostic accuracy of CT angiography and CT perfusion for cerebral vasospasm: a meta-analysis

BACKGROUND AND PURPOSE

In recent years, the role of CTA and CTP for vasospasm diagnosis in the setting of ASAH has been the subject of many research studies. The purpose of this study was to perform a meta-analysis of the diagnostic performance of CTA and CTP for vasospasm in patients with ASAH by using DSA as the criterion standard.

MATERIALS AND METHODS

The search strategy for research studies was based on the Cochrane Handbook for Systematic Reviews, including literature data bases (PubMed, Embase, Cochrane Database of Systematic Reviews, and the Web of Science) and reference lists of manuscripts published from January 1996 to February 2009. The inclusion criteria were the following: 1) published manuscripts, 2) original research studies with prospective or retrospective data, 3) patients with ASAH, 4) CTA or CTP as the index test, and 5) DSA as the reference standard. Three reviewers independently assessed the quality of these research studies by using the QUADAS tool. Pooled estimates of sensitivity, specificity, LR+, LR-, DOR, and the SROC curve were determined.

RESULTS

CTA and CTP searches yielded 505 and 214 manuscripts, respectively. Ten research studies met inclusion criteria for each CTA and CTP search. Six CTA and 3 CTP studies had sufficient data for statistical analysis. CTA pooled estimates had 79.6% sensitivity (95%CI, 74.9%-83.8%), 93.1%specificity (95%CI, 91.7%-94.3%), 18.1 LR+ (95%CI, 7.3-45.0), and 0.2 LR- (95%CI, 0.1-0.4); and CTP pooled estimates had 74.1% sensitivity (95%CI, 58.7%- 86.2%), 93.0% specificity (95% CI, 79.6%-98.7%), 9.3 LR+ (95%CI, 3.4-25.9), and 0.2 LR- (95%CI, 0.04-1.2). Overall DORs were 124.5 (95%CI, 28.4-546.4) for CTA and 43.0 (95%CI, 6.5-287.1) for CTP. Area under the SROC curve was 98 ± 2.0%for CTA and 97 ± 3.0% for CTP.

CONCLUSIONS

The high diagnostic accuracy determined for both CTA and CTP in this meta-analysis suggests that they are potentially valuable techniques for vasospasm diagnosis in ASAH. Awareness of these results may impact patient care by providing supportive evidence for more effective use of CTA and CTP imaging in ASAH.

Concurrent inspiratory muscle and cardiovascular training differentially improves both perceptions of effort and 5000 m running performance compared with cardiovascular training alone

OBJECTIVE

To examine whether inspiratory muscle training (IMT) is a useful additional technique with which to augment cardiovascular exercise training adaptations.

METHODS

16 healthy untrained males agreed to participate in the study and were randomly assigned to training (TRA; n = 8) and placebo (PLA; n = 8) groups. Pre- and post-training measurements of spirometry and maximal inspiratory mouth pressure (MIP) were taken in addition to i) maximal aerobic power (VO(2max)) and ii) 5000 m run time-trial. All subjects completed the same 4 week cardiovascular training programme which consisted of three running sessions (CV1: 5 x 1000 m, CV2: 3 x 1600 m, SP1: 20 min run) in each of the 4 weeks. IMT was performed daily by both groups using an inspiratory muscle trainer (POWERbreathe). TRA completed 30 maximal inspirations while PLA inspired 30 times against a negligible resistance.

RESULTS

Mean MIP increased significantly in both groups (TRA: 14.5 (SD 6.8)% change, PLA: 7.8 (7.4)% change) from pre- to post-training (p<0.01) but was not significantly related to changes in running performance. Mean CV1 training-repetition runs improved similarly in both groups, but RPE evaluations were significantly reduced in TRA (15.7 (0.7)) compared with PLA (16.6 (0.8)) at week 4 (p<0.05). Pre- to post-training changes in VO(2max) were well-matched between both TRA (+2.1 (2.3)%) and PLA (+1.3 (2.4)%) while post-intervention 5000 m performance was significantly augmented in TRA compared with PLA (TRA: 4.3 (1.6)%, PLA: 2.2 (1.9)%, p<0.05).

CONCLUSIONS

The addition of IMT to a cardiovascular training programme augments 5000 m running performance but exerts no additional influence over VO(2max) compared with a cardiovascular-training group. This is probably due to IMT-induced reduction in perceived effort at high ventilatory rates, which is of greater consequence to longer duration time-trial performances than incremental tests of VO(2max).

Association of a high-molecular weight arginine-binding protein of Fusobacterium nucleatum ATCC 10953 with adhesion to secretory immunoglobulin A and coaggregation with Streptococcus cristatus

INTRODUCTION

Fusobacterium nucleatum coaggregates with a diverse range of bacterial species, and binds to host tissues and proteins such as immunoglobulin. These interactions may support the attachment of a variety of organisms to oral surfaces and can facilitate the invasion of soft tissues. We hypothesized that coaggregation with streptococci and immunoglobulin binding may occur by a common adhesin sensitive to l-arginine.

METHODS

Repeated mixing of F. nucleatum with non-immune secretory immunoglobulin A (S-IgA) and recovery of non-agglutinating cells isolated a spontaneous mutant (isolate 21) of F. nucleatum that was defective in S-IgA binding. Wild-type and mutant F. nucleatum were compared by coaggregation and adhesion assays.

RESULTS

Isolate 21 exhibited significantly reduced S-IgA binding and coaggregation with oral streptococci but not with Porphyromonas gingivalis. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the mutant was deficient compared to wild-type for a single protein of approximately 360 kilodaltons. The corresponding protein was isolated from wild-type F. nucleatum protein preparations by coprecipitation with arginine-agarose beads. This protein was able to bind both Streptococcus cristatus and S-IgA. Mass spectrometry analysis indicated that this protein was closely related to putative autotransporter proteins in other F. nucleatum strains and was a 100% match to the deduced amino acid sequence of a 10,638-base-pair open reading frame in the incomplete genome sequence of F. nucleatum ATCC 10,953. Peptides identified by MS-MS analysis spanned most of the predicted amino acid sequence, suggesting that the mature protein is not subject to postsecretory cleavage.

CONCLUSION

Coaggregation represents a novel function within the autotransporter class of proteins, which are often associated with virulence.

Sodium cromoglicate: an ineffective drug or meta-analysis misused?

Sodium cromoglicate (SCG) has been available since around 1970 for the treatment of asthma and other allergic disorders in both adults and children. It has been approved for use around the world. Over the period of its development, a number of different formulations were introduced. In 1999, a systematic review of SCG use in childhood asthma was carried out and reported initially as a poster. Further systematic reviews and papers followed from the same authors and finally a Cochrane Collaboration review was published in 2003. All concluded that SCG was ineffective in paediatric asthma. Both the British Thoracic Society Guidelines for the treatment of paediatric asthma and the Model List of Essential Drugs of the WHO now reflect these conclusions. This paper looks carefully at the conclusions of these systematic reviews and raises concerns about the interpretation of the results. These failed to take adequate account of the changes with time in both the formulations used and the age groups examined, and also failed to take adequate note of the totality of information available over all end-points. One primary end-point was based on only four out of the 24 studies included in the review. Rather than having no effect, it is demonstrated that a considerable body of evidence favours SCG compared to placebo and, far from being ineffective, the drug appears to be effective particularly in older children. This article replaces a previously published version. DOI: 10.1002/pst.258.

Retracted and replaced: Sodium cromoglicate: an ineffective drug or meta-analysis misused?

The following article from Pharmaceutical Statistics, Sodium cromoglicate: an ineffective drug or meta-analysis misused? by M. T. Stevens, A. M. Edwards, J. B. L. Howell published online on 15 March 2007 in Wiley InterScience (www.interscience.wiley.com), has been retracted by agreement between the author, the journal Editor in Chief, Steven Julious, and John Wiley & Sons, Ltd. The retraction has been agreed because the article is not yet ready for publication and an early version without revisions was published in error. Replacement article pending. Copyright (c) 2007 John Wiley & Sons, Ltd.

Gene expression profiling of acute liver stress during living donor liver transplantation

During liver transplantation, the donor graft is subjected to a number of acute stresses whose molecular basis is not well-understood. The effects of surgical stress, preservation and reperfusion injury were studied in 24 consecutive living donor liver transplant (LDLT) operations. Liver biopsies were taken early in the donor operation (OPENING), after transection of the donor liver (PRECLAMP) and following implantation of the graft (post hepatic artery, [PHA]); these were evaluated for histology, tissue glutathione content and gene expression using a 19K-human cDNA microarray. LDLT was associated with an ischemia/reperfusion injury, with accumulation of small numbers of neutrophils and decreased glutathione in the PHA biopsies. Following reperfusion, the expression of 129 genes increased and 106 genes decreased when compared to OPENING levels (> or <2-fold, p < 0.01). By real-time PCR a subset of 25 genes was verified (15 increased, 10 decreased). These genes were similarly altered in another condition of acute liver stress (the response to brain-death), but not in three chronic liver disease states (HCV, HBV and PBC). This study has identified a set of genes whose expression is altered in acute, but not chronic, liver stress, likely to play a central role in the pathogenesis of acute liver injury of liver transplantation.

Thermoregulatory observations in soccer match play: professional and recreational level applications using an intestinal pill system to measure core temperature

BACKGROUND

Technological limitations associated with oesophageal and rectal temperature probes have previously limited match play observations of body temperature.

OBJECTIVE

To investigate the application of an intestinal pill system to measure core temperature during dynamic, field based, soccer matches.

METHODS

Core temperature (T(c)) was assessed using the intestinal pill system (CorTemp 2000) and changes in plasma volume were calculated using the values for haemoglobin and packed cell volume obtained before and after recreational (n = 8) and the professional soccer (n = 7) matches.

RESULTS

In the recreational match, there were significant post-match reductions in body mass (-1.6%, p<0.05) and plasma volume (-7.2%, p<0.01). Significant increases were observed in T(c) from rest to half time (p<0.01) and from half time to full time (p<0.05). In the professional match, body mass decreased by 1.9% (p<0.05) and plasma volume by 11.6% (p<0.01). T(c) increased from rest to half time (p<0.01) but was unchanged from half time to full time. Significant associations were observed between maximum oxygen consumption and match play heart rates in the second half of each match but these were not related to changes in plasma volume or T(c).

CONCLUSIONS

Intestinal temperature proved a useful method of recording core temperature during soccer match play and assisted in the measurement of alterations in thermoregulatory variables in response to both professional and recreational level soccer matches; however, technological limitations still restrict the wider application of this method, especially at a competitive level.

Efficacy and acceptability of a new topical skin lotion of sodium cromoglicate (Altoderm) in atopic dermatitis in children aged 2-12 years: a double-blind, randomized, placebo-controlled trial

BACKGROUND

Atopic dermatitis (AD) is a common inflammatory allergic disease of children. The primary anti-inflammatory therapy is topical steroids. An effective treatment without the topical and systemic adverse effects of corticosteroids would be useful. Topical formulations of sodium cromoglicate have been researched in the past, but without consistent results. We report a trial of a new aqueous skin lotion of sodium cromoglicate (Altoderm) in children with AD.

OBJECTIVES

To compare the efficacy, safety and acceptability of Altoderm lotion with a placebo control in the treatment of AD in children.

METHODS

A double-blind, controlled study in which children aged 2-12 years with AD were randomized to 12 weeks of treatment with a lotion containing 4% sodium cromoglicate (Altoderm) or the lotion base. To be included subjects had to have a SCORAD score of > or = 25 and < or = 60 at both of two clinic visits 14 days apart. Subjects continued using existing treatment which included emollients and topical steroids. The primary outcome was the change in the SCORAD score. The two groups were compared for the change in the SCORAD score from the second baseline visit to the visit after 12 weeks of treatment using an analysis of variance. Secondary outcome measures included parents' assessment of symptoms, usage of topical steroids recorded on daily diary cards, and final opinions of treatment by parent and clinician. Parents were asked about adverse effects at each clinic visit and the responses recorded.

RESULTS

Fifty-eight children were randomized to Altoderm and 56 to placebo and all were included in the intention-to-treat analysis. The mean +/- SD SCORAD scores at baseline were 41.0 +/- 9.0 (Altoderm) and 40.4 +/- 8.73 (placebo). These scores were reduced after 12 weeks by 13.2 (36%) with Altoderm and by 7.6 (20%) with placebo. The difference of 5.6 (95% confidence interval 1.0-10.3) is statistically significant (P = 0.018). Diary card symptoms improved with both treatments but the improvement was greater in the Altoderm-treated patients. Topical steroid usage was reduced in both groups and was larger in the Altoderm-treated patients. The differences were statistically significant for the mean of all symptoms, the overall skin condition and use of topical steroids. Those for itching and sleep loss were not. Treatment-related adverse events were reported in 11 subjects (Altoderm seven, placebo four). Most of these referred to irritation, redness and burning at the site of application. There were four reports of erythema and pruritus (Altoderm three, placebo one), and three reports of application site burning (Altoderm two, placebo one). None was reported as severe or very severe.

CONCLUSIONS

These results show a clinically useful benefit of this sodium cromoglicate lotion in children with moderately severe AD.

Oxygen uptake kinetics and maximal aerobic power are unaffected by inspiratory muscle training in healthy subjects where time to exhaustion is extended

The aim of this study was to determine whether 4 weeks of inspiratory muscle training (IMT) would be accompanied by alteration in cardiopulmonary fitness as assessed through moderate intensity oxygen uptake (V(.)O(2)) kinetics and maximal aerobic power (V(.)O(2max)). Eighteen healthy males agreed to participate in the study [training group (Tra) n=10, control group (Con) n=8]. Measurements of spirometry and maximal static inspiratory mouth pressure ( PI(max)) were taken pre- and post-training in addition to: (1) an incremental test to volitional exhaustion, (2) three square-wave transitions from walking to running at a moderate intensity (80% ventilatory threshold) and (3) a maximal aerobic constant-load running test to volitional fatigue for the determination of time to exhaustion ( T(lim)). Training was performed using an inspiratory muscle trainer (Powerbreathe). There were no significant differences in spirometry either between the two groups or when comparing the post- to pre-training results within each group. Mean PI(max) increased significantly in Tra ( P<0.01) and showed a trend for improvement ( P<0.08) in Con. Post-training T(lim) was significantly extended in both Tra [232.4 (22.8) s and 242.8 (20.1) s] ( P<0.01) and Con [224.5 (19.6) and 233.5 (12.7) s] ( P<0.05). Post-training T(lim) was significantly extended in Tra compared to Con ( P<0.05). In conclusion, the most plausible explanation for the stability in V(.)O(2) kinetics and V(.)O(2max) following IMT is that it is due to insufficient whole-body stress to elicit either central or peripheral cardiopulmonary adaptation. The extension of post-training T(lim) suggests that IMT might be useful as a stratagem for producing greater volumes of endurance work at high ventilatory loads, which in turn could improve cardiopulmonary fitness.

NMR structure determination and structure-based functional characterization of conserved hypothetical protein MTH1175 from Methanobacterium thermoautotrophicum

The solution structure of MTH1175, a 124-residue protein from the archaeon Methanobacterium thermoautotrophicum has been determined by NMR spectroscopy. MTH1175 is part of a family of conserved hypothetical proteins (COG1433) with unknown functions which contains multiple paralogs from all complete archaeal genomes and the archaeal gene-rich bacterium Thermotoga maritima. Sequence similarity indicates this protein family may be related to the nitrogen fixation proteins NifB and NifX. MTH1175 adopts an alpha/beta topology with a single mixed beta-sheet, and contains two flexible loops and an unstructured C-terminal tail. The fold resembles that of Ribonuclease H and similar proteins, but differs from these in several respects, and is not likely to have a nuclease activity.

From tooth to hoof: treponemes in tissue-destructive diseases

With the advent of new molecular and immunological tools, there is better understanding of the roles that difficult to cultivate bacteria, and not-yet-cultivated bacteria such as spirochaetes, play in polymicrobial diseases. Only relatively recently have studies implicated Treponema spirochaetes in human periodontal disease, a destructive condition of the tissues supporting the teeth. A number of different Treponema species have been isolated and their surface protein components that mediate adhesion, cytotoxicity, and tissue damage have been characterized. More recently Treponema strains closely related to human oral isolates have been cultivated from active lesions of digital dermatitis, an ulcerative condition affecting the feet of cows and sheep. This condition, like periodontal disease, appears to have a polymicrobial aetiology in which enrichment for Treponema may play a crucial part. This article reviews the known mechanisms by which Treponema interact with eukaryotic host cells and tissue proteins, and how these interactions may contribute to pathogenic diversity.

Lactate and Ventilatory Thresholds Reflect the Training Status of Professional Soccer Players Where Maximum Aerobic Power is Unchanged

The aim of this study was to investigate maximum aerobic power (VO2 max) and anaerobic threshold (AT) as determinants of training status among professional soccer players. Twelve professional 1st team British male soccer players (age: 26.2 ± 3.3 years, height: 1.77 ± 0.05 m, body mass: 79.3 ± 9.4 kg) agreed to participate in the study and provided informed consent. All subjects completed a combined test of anaerobic threshold (AT) and maximum aerobic power on two occasions: Test 1) following 5 weeks of low level activity at the end of the off-season and Test 2) immediately following conclusion of the competitive season. AT was assessed as both lactate threshold (LT) and ventilatory threshold (VT). There was no change in VO2 max between Test 1 and Test 2 (63.3 ± 5.8 ml·kg(-1)·min(-1) vs. 62.1 ± 4.9 ml·kg(-1)·min(-1) respectively), however, the duration of exercise tolerance (ET) at VO2 max was significantly extended from Test 1 to Test 2 (204 ± 54 vs. 228 ± 68 s respectively) (P<0.01). LT oxygen consumption was significantly improved in Test 2 versus Test 1 (P<0.01) VT was also improved (P<0.05). There was no significant difference in VO2 (ml·kg(-1)·min(-1)) corresponding to LT and VT. The results of this study show that VO2 max is a less sensitive indicator to changes in training status in professional soccer players than either LT or VT.

Test performance indicators from a single soccer specific fitness test differentiate between highly trained and recreationally active soccer players

AIM

The aim of this study was to investigate whether a single soccer specific fitness test (SSFT) could differentiate between highly trained and recreationally active soccer players in selected test performance indicators.

METHODS

SUBJECTS

13 Academy Scholars (AS) from a professional soccer club and 10 Recreational Players (RP) agreed to participate in this study. Test 1--VO(2) max was estimated from a progressive shuttle run test to exhaustion. Test 2--The SSFT was controlled by an automated procedure and alternated between walking, sprinting, jogging and cruise running speeds. Three activity blocks (1A, 2A and 3A) were separated by 3 min rest periods in which blood lactate samples were drawn. The 3 blocks of activity (Part A) were followed by 10 min of exercise at speeds alternating between jogging and cruise running (Part B).

RESULTS

Estimated VO(2) max did not significantly differ between groups, although a trend for a higher aerobic capacity was evident in AS (p<0.09). Exercising heart rates did not differ between AS and RP, however, recovery heart rates taken from the 3 min rest periods were significantly lower in AS compared with RP following blocks 1A (124.65 b x min(-1) +/-7.73 and 133.98 b x min(-1) +/-6.63), (p<0.05) and 3A (129.91 b x min(-1) +/-10.21 and 138.85 b x min(-1) +/-8.70), (p<0.01). Blood lactate concentrations were significantly elevated in AS in comparison to RP following blocks 2A (6.91 mmol x l(-1) +/-2.67 and 4.74 mmol x l(-1) +/-1.28) and 3A (7.18 mmol x l(-1) +/-2.97 and 4.88 mmol x l(-1) +/-1.50), (p<0.05). AS sustained significantly faster average sprint times in block 3A compared with RP (3.18 sec +/-0.12 and 3.31 sec +/-0.12), (p<0.05).

CONCLUSION

The results of this study show that highly trained soccer players are able to sustain, and more quickly recover from, high intensity intermittent exercise.

A comparison of two time-domain analysis procedures in the determination of .VO(2) kinetics by pseudorandom binary sequence exercise testing

The purpose of this study was to apply and compare two time-domain analysis procedures in the determination of oxygen uptake (.VO(2)) kinetics in response to a pseudorandom binary sequence (PRBS) exercise test. PRBS exercise tests have typically been analysed in the frequency domain. However, the complex interpretation of frequency responses may have limited the application of this procedure in both sporting and clinical contexts, where a single time measurement would facilitate subject comparison. The relative potential of both a mean response time (MRT) and a peak cross-correlation time (PCCT) was investigated. This study was divided into two parts: a test-retest reliability study (part A), in which 10 healthy male subjects completed two identical PRBS exercise tests, and a comparison of the .VO(2) kinetics of 12 elite endurance runners (ER) and 12 elite sprinters (SR; part B). In part A, 95% limits of agreement were calculated for comparison between MRT and PCCT. The results of part A showed no significant difference between test and retest as assessed by MRT [mean (SD) 42.2 (4.2) s and 43.8 (6.9) s] or by PCCT [21.8 (3.7) s and 22.7 (4.5) s]. Measurement error (%) was lower for MRT in comparison with PCCT (16% and 25%, respectively). In part B of the study, the .VO(2) kinetics of ER were significantly faster than those of SR, as assessed by MRT [33.4 (3.4) s and 39.9 (7.1) s, respectively; P<0.01] and PCCT [20.9 (3.8) s and 24.8 (4.5) s; P<0.05]. It is possible that either analysis procedure could provide a single test measurement of .VO(2) kinetics; however, the greater reliability of the MRT data suggests that this method has more potential for development in the assessment of .VO(2) kinetics by PRBS exercise testing.

Protective effect of Boldo and tea infusions on the visible light-mediated pro-oxidant effects of vitamin B2, riboflavin

The effect of Boldo and black tea infusions on the pro-oxidant effects of vitamin B2, riboflavin (RF), when exposed to the action of visible light was studied. The amounts of antioxidants present in Boldo and tea infusions were evaluated by a procedure based on the bleaching of preformed 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cations and were expressed as 6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid equivalent concentrations. The quenching rate constants of singlet oxygen (1O2; [kq]Boldo = 6.0 x 10(7) M(-1) s(-1) and [kq]Tea = 3.2 x 10(7) M(-1) s(-1)) and triplet RF (3RF; [3RFkq]Boldo = 10 x 10(8) M(-1) s(-1) and [3RFkq]TEA = 3.2 x 10(8) M(-1) s(-1)) with Boldo and tea were determined by flash photolysis. These data allow a quantitative interpretation of the results obtained. Our data suggest that most of the oxygen consumption observed in the photolysis of RF in the presence of tea and Boldo infusions is caused by 1O2 reactions. The oxygen consumption quantum yield is considerably smaller than the fraction of RF triplets trapped by the additives (AH) present in the infusion, indicating that their interaction with 3RF does not lead to chemical reactions or that the AH*+ radical ions initially formed participate in secondary processes that do not consume oxygen. Boldo and tea infusions have a significant protective effect when a system containing RF and tryptophan (Trp) is exposed to visible light, not only by quenching the 1O2 and interfering with the Type-I mechanism but also by repairing the damage to Trp molecules associated with the latter mechanism.

Structural specificity of steroids in stimulating DNA synthesis and protooncogene expression in primary rat hepatocyte cultures

Among the chemical compounds of varied structure which possess liver tumour-promoting are steroids, such as estrogens, pregnenolone derivatives and anabolic steroids. Although the mechanism(s) of tumour promotion in liver by these xenobiotics is not well understood, it is clear that growth stimulation is one important element in their action. As a basis for better defining whether steroids stimulate growth by a common mechanism or fall into sub-groups with differing actions, the effects of 46 steroids on DNA synthesis and the expression of protooncogenes c-fos and c-myc were examined in primary cultures of normal rat hepatocytes. Tentative groupings of steroids have been identified based on apparent structural requirements for stimulation of DNA synthesis, and effects of auxiliary factors in modulating this growth stimulus. For a "progestin" group, insulin appeared to be permissive for stimulation of DNA synthesis, and presence of an ester or hydroxyl group at 17alpha-position in combination with a non-polar group at C(6) appeared to be required for stimulation. For the pregnenes, dexamethasone was stimulatory. Structural requirements include a non-polar substitution at 16alpha-position and presence of a 6alpha-methyl group. Androgens were weak or ineffective stimulators of DNA synthesis. Anabolic steroids were weak to strong stimulators and alteration to A ring structure in combination with non-polar substitution at 17alpha-position appeared to be required for the activity. With the exception of the anabolic steroid, dianabol, there do not appear to be strong correlation between ability to stimulate DNA synthesis and ability to induce protooncogene expression among the steroids. This study provides a starting point for future more detailed examination of growth-stimulatory mechanism(s) of action of steroids in the liver.

Unfolding of microarray data

The use of DNA microarrays for the analysis of complex biological samples is becoming a mainstream part of biomedical research. One of the most commonly used methods compares the relative abundance of mRNA in two different samples by probing a single DNA microarray simultaneously. The simplicity of this concept sometimes masks the complexity of capturing and processing microarray data. On the basis of the analysis of many of our microarray experiments, we identified the major causes of distortion of the microarray data and the sources of noise. In this study, we provide a systematic statistical approach for extraction of true expression ratios from raw microarray data, which we describe as an unfolding process. The results of this analysis are presented in the form of a model describing the relationship between the measured fluorescent intensities and the concentrations of mRNA transcripts. We developed and tested several algorithms for inference of the model parameters for the microarray data. Special emphasis is given to the statistical robustness of these algorithms, in particular resistance to outliers. We also provide methods for measurement of noise and reproducibility of the microarray experiments.

Effect of visible light on selected enzymes, vitamins and amino acids

In most cases, the presence of an endogenous photosensitizer is a requirement for visible light modification of biomolecules in animal tissues. Riboflavin (RF) is present in all aerobic cells and is a very efficient photosensitizer, presenting a complex photochemistry with a mixed type I-type II mechanisms. Visible light irradiation in the presence of RF diminished the enzymatic activity of horse radish peroxidase (HRP) only when this glyco-enzyme was deglycosilated. In contrast, the activity of catalase is inactivated via singlet oxygen, and that of lysozyme was efficiently inactivated by a mixed type I-type II mechanisms. The reactive species involved in the RF sensitized photoconversion of lysozyme and the aromatic amino acids tryptophan and tyrosine (both free in solution) is discussed. The role of ascorbate and the effect of RF photosensitized processes in biological complex systems, such as the ocular lens and tumoral cell in culture, is analyzed.

Solution structure and dynamics of yeast elongin C in complex with a von Hippel-Lindau peptide

Elongin is a transcription elongation factor that stimulates the rate of elongation by suppressing transient pausing by RNA polymerase II at many sites along the DNA. It is heterotrimeric in mammals, consisting of elongins A, B and C subunits, and bears overall similarity to a class of E3 ubiquitin ligases known as SCF (Skp1-Cdc53 (cullin)-F-box) complexes. A subcomplex of elongins B and C is a target for negative regulation by the von Hippel-Lindau (VHL) tumor-suppressor protein. Elongin C from Saccharomyces cerevisiae, Elc1, exhibits high sequence similarity to mammalian elongin C. Using NMR spectroscopy we have determined the three-dimensional structure of Elc1 in complex with a human VHL peptide, VHL(157-171), representing the major Elc1 binding site. The bound VHL peptide is entirely helical. Elc1 utilizes two C-terminal helices and an intervening loop to form a binding groove that fits VHL(157-171). Chemical shift perturbation and dynamics analyses reveal that a global conformational change accompanies Elc1/VHL(157-171) complex formation. Moreover, the disappearance of conformational exchange phenomena on the microsecond to millisecond time scale within Elc1 upon VHL peptide binding suggests a role for slow internal motions in ligand recognition.