Phylogenomics of Acinetobacter species and analysis of antimicrobial resistance genes

Introduction

Non-baumannii Acinetobacter species are increasingly isolated in the clinical setting and the environment. The aim of the present study was to analyze a genome database of 837 Acinetobacter spp. isolates, which included 798 non-baumannii Acinetobacter genomes, in order to define the concordance of classification and discriminatory power of 7-gene MLST, 53-gene MLST, and single-nucleotide polymorphism (SNPs) phylogenies.

Methods

Phylogenies were performed on Pasteur Multilocus Sequence Typing (MLST) or ribosomal Multilocus Sequence Typing (rMLST) concatenated alleles, or SNPs extracted from core genome alignment.

Results

The Pasteur MLST scheme was able to identify and genotype 72 species in the Acinetobacter genus, with classification results concordant with the ribosomal MLST scheme. The discriminatory power and genotyping reliability of the Pasteur MLST scheme were assessed in comparison to genome-wide SNP phylogeny on 535 non-baumannii Acinetobacter genomes assigned to Acinetobacter pittii, Acinetobacter nosocomialis, Acinetobacter seifertii, and Acinetobacter lactucae (heterotypic synonym of Acinetobacter dijkshoorniae), which were the most clinically relevant non-baumannii species of the A. baumannii group. The Pasteur MLST and SNP phylogenies were congruent at Robinson-Fould and Matching cluster tests and grouped genomes into four and three clusters in A. pittii, respectively, and one each in A. seifertii. Furthermore, A. lactucae genomes were grouped into one cluster within A. pittii genomes. The SNP phylogeny of A. nosocomialis genomes showed a heterogeneous population and did not correspond to the Pasteur MLST phylogeny, which identified two recombinant clusters. The antimicrobial resistance genes belonging to at least three different antimicrobial classes were identified in 91 isolates assigned to 17 distinct species in the Acinetobacter genus. Moreover, the presence of a class D oxacillinase, which is a naturally occurring enzyme in several Acinetobacter species, was found in 503 isolates assigned to 35 Acinetobacter species.

Conclusion

In conclusion, Pasteur MLST phylogeny of non-baumannii Acinetobacter isolates coupled with in silico detection of antimicrobial resistance makes it important to study the population structure and epidemiology of Acinetobacter spp. isolates.

QTc interval in anorexia nervosa: a systematic review and meta-analysis

Background

Patients with anorexia nervosa (AN) are at higher risk of sudden cardiac death. Although the underlying aetiology for this association remains unclear. It may be related to prolongation of the QT interval, which can degenerate into fatal ventricular arrhythmias. However, the presence of prolonged heart rate-corrected QT interval (QTc) in AN remains controversial, and two previous meta-analyses on AN and QTc showed contradictory findings [1,2].

Purpose

In this systematic review and meta-analysis, we aimed to evaluate if AN was associated with changes in the QTc interval and dispersion.

Methods

MEDLINE, EMBASE and COCHRANE databases were systematically searched from inception to January 2021. Random-effects meta-analysis and meta-regression were used. The inclusion criteria were (i) confirmed diagnosis of AN, (ii) measurement of QTc on electrocardiogram and (iii) peer-reviewed articles. The primary endpoint of the study was the duration of the QTc interval calculated using the Bazett (QTcB), Hodges (QTcH), Fridericia (QTcF) and Framingham (QTcFr) formulae. The secondary endpoints were QT dispersion (QTd) and QTc dispersion (QTcd).

Results

The 25 eligible studies included 5687 patients (1862 AN, 3825 control) (Figure 1: PRISMA diagram). The majority of patients were female (96.3%) with a mean age between 14.3 to 31.0 years and mean duration of disease ranging from 9.1 to 129.6 months. The mean BMI ranged from 13.7 to 18.5 kg/m2. Pooled analysis did not show significant prolongation between AN versus control in QTcB (mean difference (MD) MD 4.9ms, 95% CI −3.2, 13.1ms, p=0.23; I2=95%; n=24/25 studies; Figure 2A), QTcH (MD 1.3ms, 95% CI −8.5, 11.2ms, p=0.79; I2=71%; n=3/25 studies), and QTcF (MD 3.1ms, 95% CI −21.6, 27.7ms, p=0.81; I2=97%; n=3/25 studies). Only two studies reporting QTcFr showed a significant prolongation between AN and control (MD 15.9ms, 95% CI 0.0, 31.8ms, p=0.05, I2=65%; n=2/25 studies; Figure 2B). However, QTd and QTcd were significantly greater in AN than control (MD 21.3ms, 95% CI 10.4, 32.3ms, p=0.0001, I2=94%; Figure 2C and MD 16.9ms, 95% CI 4.5, 29.3ms, p=0.007 I2=93%; Figure 2D, respectively).

Conclusion

To the best of our knowledge, this is the largest meta-analysis of QTc in AN and the first meta-analysis exploring the significance of QTd and QTcd in AN. AN was not found to be associated with prolongation of QTc calculated using the Bazett, Fridericia and Hodges formulae. However, an association of AN with prolonged QTc was observed in the studies using the Framingham formula. More pronounced dispersion (QTd and QTcd) was also observed in patients with AN.

Funding Acknowledgement

Type of funding sources: None.

Strategic placement of automated external defibrillators (AEDs) for cardiac arrests in public locations and private residences

•

We ranked businesses for their ability to fill gaps in the AED landscape.

•

23% of OHCAs in public, and 4% in homes, were within 100 m of an existing AED.

•

Many businesses can simultaneously improve coverage of arrests in public and homes.

•

Rankings were largely robust to the coverage radius used (100 m, 200 m, and 500 m).

•

Even if all 5006 business locations hosted AEDs, large gaps in OHCA coverage remain.

Aim

Methods

Results

Conclusion

Thiomicrorhabdus heinhorstiae sp. nov. and Thiomicrorhabdus cannonii sp. nov.: novel sulphur-oxidizing chemolithoautotrophs isolated from the chemocline of Hospital Hole, an anchialine sinkhole in Spring Hill, Florida, USA

Two sulphur-oxidizing, chemolithoautotrophic aerobes were isolated from the chemocline of an anchialine sinkhole located within the Weeki Wachee River of Florida. Gram-stain-negative cells of both strains were motile, chemotactic rods. Phylogenetic analysis of the 16S rRNA gene and predicted amino acid sequences of ribosomal proteins, average nucleotide identities, and alignment fractions suggest the strains HH1^T and HH3^T represent novel species belonging to the genus Thiomicrorhabdus. The genome G+C fraction of HH1^T is 47.8 mol% with a genome length of 2.61 Mb, whereas HH3^T has a G+C fraction of 52.4 mol% and 2.49 Mb genome length. Major fatty acids of the two strains included C_16 : 1, C_18 : 1 and C_16 : 0, with the addition of C_10:0 3-OH in HH1^T and C_12 : 0 in HH3^T. Chemolithoautotrophic growth of both strains was supported by elemental sulphur, sulphide, tetrathionate, and thiosulphate, and HH1^T was also able to use molecular hydrogen. Neither strain was capable of heterotrophic growth or use of nitrate as a terminal electron acceptor. Strain HH1^T grew from pH 6.5 to 8.5, with an optimum of pH 7.4, whereas strain HH3^T grew from pH 6 to 8 with an optimum of pH 7.5. Growth was observed between 15-35 °C with optima of 32.8 °C for HH1^T and 32 °C for HH3^T. HH1^T grew in media with [NaCl] 80-689 mM, with an optimum of 400 mM, while HH3^T grew at 80-517 mM, with an optimum of 80 mM. The name Thiomicrorhabdus heinhorstiae sp. nov. is proposed, and the type strain is HH1^T (=DSM 111584^T=ATCC TSD-240^T). The name Thiomicrorhabdus cannonii sp. nov is proposed, and the type strain is HH3^T (=DSM 111593^T=ATCC TSD-241^T).

Sub-organism (acetylcholinesterase activity), population (survival) and chemical concentration responses reinforce mechanisms of antagonism associated with malathion toxicity

Within human modified ecosystems the effects of individual stressors are difficult to establish amid co-occurring biological processes, environmental gradients and other stressors. Coupled examination of several endpoints across different levels of organisation may help elucidate the individual and combined effects of stressors and interactions. Malathion is a commonly used organophosphate pesticide that contaminates freshwaters and has strong negative effects on aquatic biota. However, both other stressors (e.g. increased sediment) and common ecosystem components (e.g. macrophytes and variable pH) can reduce the aqueous concentrations of malathion, reducing its toxic effects. We conducted a fully orthogonal bioassay to examine how pH (at 7 and 7.8) and sorptive processes (across two levels of kaoline clay 0 and 24 g L^-1) affected aqueous malathion concentrations and toxicity in an aquatic invertebrate genus. Survival and acetylcholinesterase activity as a sub-organism response were examined in the mayfly Coloburiscoides spp. (Ephemeroptera; Coluburiscidae). Measured aqueous malathion concentrations decreased with increased pH and in the presence of kaolin clay. Survival declined with increasing malathion concentrations and exposure period. Results further identify that antagonism of malathion toxicity was associated with both pH (alkaline hydrolysis) and effects associated with sediment independent of pH (driven by sorptive processes). However, model predictions varied associated with target and measured concentrations and concentrations examined. Antagonistic effects were most apparent using subset target malathion concentrations because of the dominant effect of malathion at high concentrations. Acetylcholinesterase activity, identified repression occurred across all treatments and did not identify antagonistic interactions, but these results were similar to survival responses at the time points examined (i.e. 120 h). Examination of chemistry, acetylcholinesterase, and survival, affords greater understanding of stressor effects and their interactions. Measured malathion concentrations may underestimate effects on aquatic biota; not because of synergism among stressors, but because of strong effects despite antagonism.

Effectiveness of Short-Term Heat Acclimation on Intermittent Sprint Performance With Moderately Trained Females Controlling for Menstrual Cycle Phase

Introduction

Investigate the effectiveness of short-term heat acclimation (STHA), over 5-days (permissive dehydration), on an intermittent sprint exercise protocol (HST) with females. Controlling for menstrual cycle phase.

Materials and Methods

Ten, moderately trained, females (Mean [SD]; age 22.6 [2.7] y; stature 165.3 [6.2] cm; body mass 61.5 [8.7] kg; V.⁢O2⁢peak 43.9 [8.6] mL⋅kg^–1⋅min^–1) participated. The HST (31.0°C; 50%RH) was 9 × 5 min (45-min) of intermittent exercise, based on exercise intensities of female soccer players, using a motorized treadmill and Wattbike. Participants completed HST1 vs. HST2 as a control (C) trial. Followed by 90 min, STHA (no fluid intake), for five consecutive days in 39.5°C; 60%RH, using controlled-hyperthermia (∼rectal temperature [T_re] 38.5°C). The HST3 occurred within 1 week after STHA. The HST2 vs HST3 trials were in the luteal phase, using self-reported menstrual questionnaire and plasma 17β-estradiol.

Results

Pre (HST2) vs post (HST3) STHA there was a reduction at 45-min in T_re by 0.20°C (95%CI −0.30 to −0.10°C; d = 0.77); T¯s⁢k (−0.50; −0.90 to −0.10°C; d = 0.80); and T¯b (−0.25; −0.35 to −0.15°C; d = 0.92). Cardiac frequency reduced at 45-min (−8; −16 to −1 b⋅min^–1; d = 1.11) and %PV increased (7.0; −0.4 to 14.5%: d = 1.27). Mean power output increased across all nine maximal sprints by 56W (−26 to 139W; d = 0.69; n = 9). There was limited difference (P > 0.05) for these measures in HST1 vs HST2 C trial.

Discussion

Short-term heat acclimation (5-days) using controlled-hyperthermia, leads to physiological adaptation during intermittent exercise in the heat, in moderately trained females when controlling for menstrual cycle phase.

Walking cadence required to elicit criterion moderate-intensity physical activity is moderated by fitness status

The aims of this study were to estimate the walking cadence required to elicit a VO₂reserve (VO₂R) of 40% and determine if fitness status moderates the relationship between walking cadence and %VO₂R. Twenty participants (10 male, mean(s) age 32(10) years; VO₂max 45(10) mL·kg^-1·min^-1) completed resting and maximal oxygen consumption tests prior to 7 x 5-min bouts of treadmill walking at increasing speed while wearing an Apple Watch and measuring oxygen consumption continuously. The 7 x 5-min exercise bouts were performed at speeds between 3 and 6 km·h^-1 with 5-min seated rest following each bout. Walking cadence measured at each treadmill speed was recorded using the Apple Watch "Activity" app. Using Bayesian regression, we predict that participants need a walking cadence of 138 to 140 steps·min^-1 to achieve a VO₂R of 40%. However, these values are moderated by fitness status such that those with lower fitness can achieve 40% VO₂R at a slower walking cadence. The results suggest that those with moderate fitness need to walk at ~40% higher than the currently recommended walking cadence (100 steps·min^-1) to elicit moderate-intensity physical activity. However, walking cadence required to achieve moderate-intensity physical activity is moderated by fitness status.

Does care at a cardiac arrest centre improve outcome after out-of-hospital cardiac arrest? - A systematic review

AIM

To perform a systematic review to answer 'In adults with attempted resuscitation after non-traumatic cardiac arrest does care at a specialised cardiac arrest centre (CAC) compared to care in a healthcare facility not designated as a specialised cardiac arrest centre improve patient outcomes?'

METHODS

The PRISMA guidelines were followed. We searched bibliographic databases (Embase, MEDLINE and the Cochrane Library (CENTRAL)) from inception to 1st August 2018. Randomised controlled trials (RCTs) and non-randomised studies were eligible for inclusion. Two reviewers independently scrutinized studies for relevance, extracted data and assessed quality of studies. Risk of bias of studies and quality of evidence were assessed using ROBINS-I tool and GRADEpro respectively. Primary outcomes were survival to 30 days with favourable neurological outcomes and survival to hospital discharge with favourable neurological outcomes. Secondary outcomes were survival to 30 days, survival to hospital discharge and return of spontaneous circulation (ROSC) post-hospital arrival for patients with ongoing resuscitation. This systematic review was registered in PROSPERO (CRD 42018093369) RESULTS: We included data from 17 observational studies on out-of-hospital cardiac arrest (OHCA) patients in meta-analyses. Overall, the certainty of evidence was very low. Pooling data from only adjusted analyses, care at CAC was not associated with increased likelihood of survival to 30 days with favourable neurological outcome (OR 2.92, 95% CI 0.68-12.48) and survival to 30 days (OR 2.14, 95% CI 0.73-6.29) compared to care at other hospitals. Whereas patients cared for at CACs had improved survival to hospital discharge with favourable neurological outcomes (OR 2.22, 95% CI 1.74-2.84) and survival to hospital discharge (OR 1.85, 95% CI 1.46-2.34).

CONCLUSIONS

Very low certainty of evidence suggests that post-cardiac arrest care at CACs is associated with improved outcomes at hospital discharge. There remains a need for high quality data to fully elucidate the impact of CACs.

Pan-Canadian Framework for Palliative and End-of-Life Care Research

Background and context: Ongoing advances have been made in the conceptualization and operationalization of palliative and end-of-life care (PEOLC) (e.g., palliative approaches to care, early identification of people who would benefit from palliative care). In addition, Canada has been a leader in PEOLC research and continues to have an internationally recognized research community. However, many Canadians continue to experience unnecessary pain and suffering at the end of life and receive care inconsistent with their goals and preferences. Within this context, the Canadian Cancer Research Alliance (CCRA) sought to develop a national research framework to guide Canada's cancer research funders in response to their strategic priority to improve the patient experience and quality of life for all cancer patients. Aim: To develop and implement a national framework and recommendations to enable funders to capitalize on existing research strengths and build capacity to address unmet needs to advance the field and broaden the scope, beyond its historical affiliation with advanced cancer, to include PEOLC for all those living and dying with life-limiting conditions. Strategy/Tactics: The framework's development was informed by multiple approaches, including: a strategic literature review; an analysis of PEOLC research funding in Canada from 2005-13; and an online survey and key informant interviews from the broader stakeholder community. Program/Policy process: A working group of CCRA member representatives and palliative care experts met regularly to provide guidance and feedback to a consultant who synthesized the data and formulated recommendations. In total, > 200 stakeholders (e.g., patients, caregivers, researchers, volunteers, practitioners, decision-makers, and policy-makers) provided input through the survey and interviews. Outcomes: The Pan-Canadian Framework for Palliative and End-of-Life Research was released March 2017. It emphasizes priorities for research funding across three broad themes: 1) Transforming models of care; 2) Patient and family centredness; and 3) Ensuring equity. The identified research priorities are underpinned by four building blocks: capacity building; knowledge, synthesis, exchange, and implementation; data access and standardization; and research network development. What was learned: Successful implementation of the framework's recommendations requires strong leadership from champions within the community. The formation of the Pan-Canadian Palliative Care Research Collaborative led by palliative care clinician-researchers, in response to the identified need for a research network, is an example of an early success resulting from release of the framework. Continued efforts are needed to ensure ongoing uptake of the framework's recommendations. CCRA members have commenced planning to identify next steps for joint action.

Measuring Moderate-Intensity Exercise with the Apple Watch: Validation Study

Background

Moderate fitness levels and habitual exercise have a protective effect for cardiovascular disease, stroke, type 2 diabetes, and all-cause mortality. The Apple Watch displays exercise completed at an intensity of a brisk walk or above using a green “exercise” ring. However, it is unknown if the exercise ring accurately represents an exercise intensity comparable to that defined as moderate-intensity. In order for health professionals to prescribe exercise intensity with confidence, consumer wearable devices need to be accurate and precise if they are to be used as part of a personalized medicine approach to disease management.

Objective

The aim of this study was to examine the validity and reliability of the Apple Watch for measuring moderate-intensity exercise, as defined as 40-59% oxygen consumption reserve (VO₂R).

Methods

Twenty recreationally active participants completed resting oxygen consumption (VO₂rest) and maximal oxygen consumption (VO₂ max) tests prior to a series of 5-minute bouts of treadmill walking at increasing speed while wearing an Apple Watch on both wrists, and with oxygen consumption measured continuously. Five-minute exercise bouts were added until the Apple Watch advanced the green “exercise” ring by 5 minutes (defined as the treadmill inflection speed). Validity was examined using a one-sample t-test, with interdevice and intradevice reliability reported as the standardized typical error and intraclass correlation.

Results

The mean %VO₂R at the treadmill inflection speed was 30% (SD 7) for both Apple Watches. There was a large underestimation of moderate-intensity exercise (left hand: mean difference = -10% [95% CI -14 to -7], d=-1.4; right hand: mean difference = -10% [95% CI -13 to -7], d=-1.5) when compared to the criterion of 40% VO₂R. Standardized typical errors for %VO₂R at the treadmill inflection speed were small to moderate, with intraclass correlations higher within trials compared to between trials.

Conclusions

The Apple Watch threshold for moderate-intensity exercise was lower than the criterion, which would lead to an overestimation of moderate-intensity exercise minutes completed throughout the day.

A Proposed Mechanism for Development of CTE Following Concussive Events: Head Impact, Water Hammer Injury, Neurofilament Release, and Autoimmune Processes

During the past decade, there has been an increasing interest in early diagnosis and treatment of traumatic brain injuries (TBI) that lead to chronic traumatic encephalopathy (CTE). The subjects involved range from soldiers exposed to concussive injuries from improvised explosive devices (IEDs) to a significant number of athletes involved in repetitive high force impacts. Although the forces from IEDs are much greater by a magnitude than those from contact sports, the higher frequency associated with contact sports allows for more controlled assessment of the mechanism of action. In our study, we report findings in university-level women soccer athletes followed over a period of four and a half years from accession to graduation. Parameters investigated included T1-, T2-, and susceptibility-weighted magnetic resonance images (SWI), IMPACT (Immediate Post-Concussion Assessment and Cognitive Testing), and C3 Logix behavioral and physiological assessment measures. The MRI Studies show several significant findings: first, a marked increase in the width of sulci in the frontal to occipital cortices; second, an appearance of subtle hemorrhagic changes at the base of the sulci; third was a sustained reduction in total brain volume in several soccer players at a developmental time when brain growth is generally seen. Although all of the athletes successfully completed their college degree and none exhibited long term clinical deficits at the time of graduation, the changes documented by MRI represent a clue to the pathological mechanism following an injury paradigm. The authors propose that our findings and those of prior publications support a mechanism of injury in CTE caused by an autoimmune process associated with the release of neural proteins from nerve cells at the base of the sulcus from a water hammer injury effect. As evidence accumulates to support this hypothesis, there are pharmacological treatment strategies that may be able to mitigate the development of long-term disability from TBI.

Predicting Post-Discharge Outcome

The ability of members of the multidisciplinary team and of elderly patients themselves to predict how patients will cope at home influences the successful outcome of discharge from hospital. Following the introduction of structured assessment of the physical, psychological and social function of patients on an acute elderly care unit, a study was undertaken to compare the predictive ability of the primary nurse, the patient and the occupational therapist.

Overall, results suggested a high level of accuracy of predictions. There was a trend for the occupational therapist to predict more accurately (83.6%) than the patient (80.7%) or the primary nurse (72.5%). Where the predictions were incorrect, the patients erred on the side of optimism (78% optimistic) whereas the nurses were more pessimistic (69% pessimistic). Further studies to look at the reliability of outcome predictions by health professionals and the patients themselves would be useful in the overall management of the discharge of elderly people from hospital.

Biofilm Morphotypes and Population Structure among Staphylococcus epidermidis from Commensal and Clinical Samples

Bacterial species comprise related genotypes that can display divergent phenotypes with important clinical implications. Staphylococcus epidermidis is a common cause of nosocomial infections and, critical to its pathogenesis, is its ability to adhere and form biofilms on surfaces, thereby moderating the effect of the host’s immune response and antibiotics. Commensal S. epidermidis populations are thought to differ from those associated with disease in factors involved in adhesion and biofilm accumulation. We quantified the differences in biofilm formation in 98 S. epidermidis isolates from various sources, and investigated population structure based on ribosomal multilocus typing (rMLST) and the presence/absence of genes involved in adhesion and biofilm formation. All isolates were able to adhere and form biofilms in in vitro growth assays and confocal microscopy allowed classification into 5 biofilm morphotypes based on their thickness, biovolume and roughness. Phylogenetic reconstruction grouped isolates into three separate clades, with the isolates in the main disease associated clade displaying diversity in morphotype. Of the biofilm morphology characteristics, only biofilm thickness had a significant association with clade distribution. The distribution of some known adhesion-associated genes (aap and sesE) among isolates showed a significant association with the species clonal frame. These data challenge the assumption that biofilm-associated genes, such as those on the ica operon, are genetic markers for less invasive S. epidermidis isolates, and suggest that phenotypic characteristics, such as adhesion and biofilm formation, are not fixed by clonal descent but are influenced by the presence of various genes that are mobile among lineages.

Impact Evaluation of an After-school Cooking Skills Program in a Disadvantaged Community: Back to Basics

PURPOSE

Few efficacious child obesity interventions have been converted into ongoing community programs in the after-school setting. The aim of this study was to evaluate the impact of phase 2 of the Back to Basics cooking club on dietary behaviours and fruit and vegetable variety in a population at risk of obesity at a low income school with > 10% indigenous population.

METHODS

Baseline and 3-month dietary intake and social cognitive theory (SCT) constructs were collected in 51 children, mean age 9 years, 61% female. McNemar tests were used for comparison of proportions between categorical variables. Cohen's d was used to compare effect sizes across different measures.

RESULTS

Consumption of one or more fruit servings per day significantly increased from 41% to 67% (P = 0.02, d = 0.13) and there was a trend for increasing the weekly variety of fruit and vegetables. The SCT constructs assessed within the current study improved significantly (P < 0.05), with moderate to large effect sizes (d = 0.33-0.78).

CONCLUSION

This study documents that a previous efficacious healthy lifestyle program can be adapted for use as an obesity prevention program addressing improvements in vegetable and fruit intakes in a low income community with a relatively high indigenous population.

Towards a systematic analysis of human short-chain dehydrogenases/reductases (SDR): Ligand identification and structure-activity relationships

Short-chain dehydrogenases/reductases (SDRs) constitute a large, functionally diverse branch of enzymes within the class of NAD(P)(H) dependent oxidoreductases. In humans, over 80 genes have been identified with distinct metabolic roles in carbohydrate, amino acid, lipid, retinoid and steroid hormone metabolism, frequently associated with inherited genetic defects. Besides metabolic functions, a subset of atypical SDR proteins appears to play critical roles in adapting to redox status or RNA processing, and thereby controlling metabolic pathways. Here we present an update on the human SDR superfamily and a ligand identification strategy using differential scanning fluorimetry (DSF) with a focused library of oxidoreductase and metabolic ligands to identify substrate classes and inhibitor chemotypes. This method is applicable to investigate structure-activity relationships of oxidoreductases and ultimately to better understand their physiological roles.

Individualisation of time-motion analysis: a method comparison and case report series

This study compared the intensity distribution of time-motion analysis data, when speed zones were categorized by different methods. 12 U18 players undertook a routine battery of laboratory- and field-based assessments to determine their running speed corresponding to the respiratory compensation threshold (RCT), maximal aerobic speed (MAS), maximal oxygen consumption (vV˙O2max) and maximal sprint speed (MSS). Players match-demands were tracked using 5 Hz GPS units in 22 fixtures (50 eligible match observations). The percentage of total distance covered running at high-speed (%HSR), very-high speed (%VHSR) and sprinting were determined using the following speed thresholds: (1) arbitrary; (2) individualised (IND) using RCT, vV˙O2max and MSS; (3) individualised via MAS per se; (4) individualised via MSS per se; and (5) individualised using MAS and MSS as measures of locomotor capacities (LOCO). Using MSS in isolation resulted in 61% and 39% of player's % HSR and % VHSR, respectively, being incorrectly interpreted, when compared to the IND technique. Estimating the RCT from fractional values of MAS resulted in erroneous interpretations of % HSR in 50% of cases. The present results suggest that practitioners and researchers should avoid using singular fitness characteristics to individualise the intensity distribution of time-motion analysis data. A combination of players' anaerobic threshold, MAS, and MSS characteristics are recommended to individualise player-tracking data.

Sodium bicarbonate supplementation and ingestion timing: does it matter?

Although a considerable amount of literature exists on the ergogenic potential of ingesting sodium bicarbonate (NaHCO3) before short-term, high-intensity exercise, very little exists on optimal loading times before exercise. The purpose of this study was to determine the influence of NaHCO3 supplementation timing on repeated sprint ability (RSA). Eight men completed 3 (randomized and counterbalanced) trials of ten 10-second sprints separated by 50 seconds of active recovery (1:5 work-to-rest) on a nonmotorized treadmill. Before each trial, the subjects ingested 0.3 g·kg(-1) body weight of NaHCO3 at 60 (H1), 120 (H2), or 180 (H3) minutes before exercise. Additionally, the subjects were assessed for any side effects (gastrointestinal [GI] discomfort) from the NaHCO3 ingestion via a visual analog scale (VAS). Blood buffering was assessed using a 2-way analysis of variance (ANOVA) with repeated measures, whereas repeated sprint performance and GI discomfort were assessed via a 1-way ANOVA with repeated measures. Blood-buffering capacity was not different at preexercise times (HCO3(-) [millimoles per liter] H1: 30.2 ± 0.4, H2: 30.9 ± 0.6, H3: 31.2 ± 0.6; p > 0.74). Average speed, average power, and total distance covered progressively declined over the 10 sprints; however, there was no difference between conditions (p > 0.22). The incidence of GI discomfort was significantly higher (p < 0.05) from preingestion at all time points with the exception of 180 minutes, whereas severity was only different between 90 and 180 minutes. Ingestion times (between 60 and 180 minutes) did not influence the blood buffering or the ergogenic potential of NaHCO3 as assessed by RSA. However, VAS scores indicated that at 180 minutes postingestion, an individual is less prone to experiencing significant GI discomfort.

Short term benefits of post-operative oral dietary supplements in surgical patients

The present study was undertaken to investigate the short term clinical efficacy of oral dietary supplements administered post-operatively to patients undergoing predetermined moderate to severe gastrointestinal surgery. Trial end points for comparison included effects of oral dietary supplements on nutritional intake, nutritional status and incidence of serious complications. 54 patients who were scheduled to undergo predetermined moderate to major gastrointestinal surgical procedures entered the study. They were randomly assigned to receive a normal ward diet post-operatively or the same diet supplemented ad libitum by an oral nutritional sip feed. The study period was defined as commencing from the day patients were adjudged to be capable of ingesting 'free fluids' to the day of hospital discharge. 40 patients (20 in each group) completed the study. The mean daily energy intake (KCal/day) assessed from 7 day food diaries was significantly higher in the treatment group (1833 +/- SEM 99) than in the control group (1108 +/- 56, p < 0.0001). This increase occurred not only as a consequence of energy intake from the oral dietary supplements (470 +/- 30) but also because more energy was consumed from the ward diet by the treatment than the control patients (1353 +/- 92 vs 1108 +/- 56, p < 0.02). The mean daily protein intake g/day in the treatment group (66.0 +/- 3.4) was also greater than in the control group (52.9 +/- 29 p < 0.0001). This difference was due solely to the intake in protein from the oral dietary supplements (15.7 +/- 1.0), protein intake from the ward diet being similar in the treatment (50.1 +/- 3.2) and control (52.9 +/- 29) groups. Patients in the treatment group maintained their pre-operative weight where as control patients had lostsignificant amount of their pre-operative weight by study day 3 (4.5 +/- 12 kg and by discharge (4.7 +/- 1.2 kg, p < 0.02). Pre-operative muscle function as evidenced by grip strength dynamometry decreased to a greater extent in the control than treatment group patients by study day 3 (14.6 +/- 2.2 KPa vs 2.8 +/- 2.4 < 0.03) and by discharge (10.4 +/- 3.1 KPa vs 0.10 +/- 1.9 p < 0.03). The incidence of serious infections (pneumonia, wound infection) was significantly higher in the control group (10) than in the treatment group (3, p < 0.02). It is concluded that the prescription of oral dietary supplements on an ad libitum basis to post-operative patients undergoing moderate to major gastrointestinal surgery results in clinically significant short term benefits.

Aspartame in conjunction with carbohydrate reduces insulin levels during endurance exercise

BACKGROUND

As most sport drinks contain some form of non-nutritive sweetener (e.g. aspartame), and with the variation in blood glucose regulation and insulin secretion reportedly associated with aspartame, a further understanding of the effects on insulin and blood glucose regulation during exercise is warranted. Therefore, the aim of this preliminary study was to profile the insulin and blood glucose responses in healthy individuals after aspartame and carbohydrate ingestion during rest and exercise.

FINDINGS

Each participant completed four trials under the same conditions (45 min rest + 60 min self-paced intense exercise) differing only in their fluid intake: 1) carbohydrate (2% maltodextrin and 5% sucrose (C)); 2) 0.04% aspartame with 2% maltodextrin and 5% sucrose (CA)); 3) water (W); and 4) aspartame (0.04% aspartame with 2% maltodextrin (A)). Insulin levels dropped significantly for CA versus C alone (43%) between pre-exercise and 30 min, while W and A insulin levels did not differ between these time points.

CONCLUSIONS

Aspartame with carbohydrate significantly lowered insulin levels during exercise versus carbohydrate alone.