A wearable sensor for the detection of sodium and potassium in human sweat during exercise

© 2020 The Author(s) The SwEatch platform, a wearable sensor for sampling and measuring the concentration of electrolytes in human sweat in real time, has been improved in order to allow the sensing of two analytes. The solid contact ion-sensitive electrodes (ISEs) for the detection of Na+ and K+ have been developed in two alternative formulations, containing either poly(3,4-ethylenedioxythiophene) (PEDOT) or poly(3-octylthiophene-2,5-diyl) (POT) as a conductive polymer transducing component. The solution-processable POT formulation simplifies the fabrication process, and sensor to sensor reproducibility has been improved via partial automation using an Opentron® automated pipetting robot. The resulting electrodes showed good sensitivity (52.4 ± 6.3 mV/decade (PEDOT) and 56.4 ± 2.2 mV/decade (POT) for Na+ ISEs, and 45.7 ± 7.4 mV/decade (PEDOT) and 54.3 ± 1.5 mV/decade (POT) for K+) and excellent selectivity towards potential interferents present in human sweat (H+, Na+, K+, Mg2+, Ca2+). The 3D printed SwEatch platform has been redesigned to incorporate a double, mirrored fluidic unit which is capable of drawing sweat from the skin through passive capillary action and bring it in contact with two independent electrodes. The potentiometric signal generated by the electrodes is measured by an integrated electronics board, digitised and transmitted via Bluetooth to a laptop. The results obtained from on-body trials on athletes during cycling show a relatively small increase in sodium (1.89 mM–2.97 mM) and potassium (3.31 mM–7.25 mM) concentrations during the exercise period of up to 90 min

Heterologous Expression of a Membrane-Spanning Auxin Importer: Implications for Functional Analyses of Auxin Transporters

Biochemical studies of plant auxin transporters in vivo are made difficult by the presence of multiple auxin transporters and auxin-interacting proteins. Furthermore, the expression level of most such transporters in plants is likely to be too low for purification and downstream functional analysis. Heterologous expression systems should address both of these issues. We have examined a number of such systems for their efficiency in expressing AUX1 from Arabidopsis thaliana. We find that a eukaryotic system based upon infection of insect cells with recombinant baculovirus provides a high level, easily scalable expression system capable of delivering a functional assay for AUX1. Furthermore, a transient transfection system in mammalian cells enables localization of AUX1 and AUX1-mediated transport of auxin to be investigated. In contrast, we were unable to utilise P. pastoris or L. lactis expression systems to reliably express AUX1

Fibrosis Progression Rate in Biopsy-Proven Nonalcoholic Fatty Liver Disease Among People With Diabetes Versus People Without Diabetes: A Multicenter Study

Background & aimsThere are limited data regarding fibrosis progression in biopsy-proven nonalcoholic fatty liver disease (NAFLD) in people with type 2 diabetes mellitus (T2DM) compared with people without T2DM. We assessed the time to fibrosis progression in people with T2DM compared with people without T2DM in a large, multicenter, study of people with NAFLD who had paired liver biopsies.MethodsThis study included 447 adult participants (64% were female) with NAFLD who had paired liver biopsies more than 1 year apart. Liver histology was systematically assessed by a central pathology committee blinded to clinical data. The primary outcome was the cumulative incidence of a ≥1-stage increase in fibrosis in participants with T2DM compared with participants without T2DM.ResultsThe mean (SD) age and body mass index (calculated as weight in kilograms divided by the square of the height in meters) were 50.9 (11.5) years and 34.7 (6.3), respectively. The median time between biopsies was 3.3 years (interquartile range, 1.8-6.1 years). Participants with T2DM had a significantly higher cumulative incidence of fibrosis progression at 4 years (24% vs 20%), 8 years (60% vs 50%), and 12 years (93% vs 76%) (P = .005). Using a multivariable Cox proportional hazards model adjusted for multiple confounders, T2DM remained an independent predictor of fibrosis progression (adjusted hazard ratio, 1.69; 95% CI, 1.17-2.43; P = .005). The cumulative incidence of fibrosis regression by ≥1 stage was similar in participants with T2DM compared with participants without T2DM (P = .24).ConclusionsIn this large, multicenter cohort study of well-characterized participants with NAFLD and paired liver biopsies, we found that fibrosis progressed faster in participants with T2DM compared with participants without T2DM. These data have important implications for clinical practice and trial design

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

Identification of novel transaminases from a 12-aminododecanoic acid-metabolizing Pseudomonas strain

A Pseudomonas species [Pseudomonas sp. strain amino alkanoate catabolism (AAC)] was identified that has the capacity to use 12-aminododecanoic acid, the constituent building block of homo-nylon-12, as a sole nitrogen source. Growth of Pseudomonas sp. strain AAC could also be supported using a range of additional ω-amino alkanoates. This metabolic function was shown to be most probably dependent upon one or more transaminases (TAs). Fourteen genes encoding putative TAs were identified from the genome of Pseudomonas sp. AAC. Each of the 14 genes was cloned, 11 of which were successfully expressed in Escherichia coli and tested for activity against 12-aminododecanoic acid. In addition, physiological functions were proposed for 9 of the 14 TAs. Of the 14 proteins, activity was demonstrated in 9, and of note, 3 TAs were shown to be able to catalyse the transfer of the ω-amine from 12-aminododecanoic acid to pyruvate. Based on this study, three enzymes have been identified that are promising biocatalysts for the production of nylon and related polymers

Detection of heightened emotional activity in commercial airline crews: A reliability study

Behavioral markers are used in training and assessment of nontechnical skills (NTSs). This study tested the reliability of a unique set of markers designed to help assess heightened emotional activity (HEA) as a response to perceived threats. Using five markers that represent instances of negative emotional states, 27 commercial airline pilots recorded their observations of HEA in eight video vignettes of scripted flight deck situations. The raters’ scores were analyzed using Cronbach’s alpha for dichotomous data. The alpha statistics indicated high inter-rater reliability across all five HEAs. This study demonstrates that the chosen instances of HEA can be reliably identified by airline pilots

Effect of working consecutive night shifts on sleep time, prior wakefulness, perceived levels of fatigue and performance on a psychometric test in emergency registrars

Objective: To evaluate the effect of working consecutive night shifts on sleep time, prior wakefulness, perceived levels of fatigue and psychomotor performance in a group of Australian emergency registrars. Methods: A prospective observational study with a repeated within-subjects component was conducted. Sleep time was determined using sleep diaries and activity monitors. Subjective fatigue levels and reciprocal reaction times were evaluated before and after day and nightshifts. Results: A total of 11 registrars participated in the study with 120 shifts analysed. Sleep time was found to be similar during consecutive night and day shifts. The mean number of hours spent awake before the end of a night shift was 14.33. Subjective fatigue scores were worst at the end of a night shift. There was no difference in reciprocal reaction time between the end of night shift and the start of day shift. Conclusions: Registrars sleep a similar amount of time surrounding night and day shifts. Despite reporting the highest levels of fatigue at the end of a night shift, there is no significant difference in reaction times at the end of night shift compared with the beginning of day shift. This correlates with the finding that at the end of night shift the registrars have been awake for less than 16 h, which is the point at which psychomotor performance is expected to decline

Systemic reactions and anaphylaxis with an acute serum tryptase ≥14 μg/L: retrospective characterisation of aetiology, severity and adherence to National Institute of Health and Care Excellence (NICE) guidelines for serial tryptase measurements and specialist referral.

AIMS To characterise patients with systemic reactions and anaphylaxis with an acute serum tryptase of ≥14 μg/L against recently published World Allergy Organisation (WAO) diagnostic criteria. To also perform a clinical audit to assess adherence to National Institute of Health and Care Excellence (NICE) guideline recommendations regarding serial tryptase measurements and specialist referral. METHODS A systematic retrospective survey (2006-2010) was carried out (n=171; males=86; mean age±SD 48±20 years) and data were extracted from emergency department and specialist allergy clinic records. RESULTS 34 patients (20%) had a grade 1 reaction, 61 (36%) grade 2, 46 (27%) grade 3 and 6 patients (4%) grade 4 (24 patients (13%) could not be graded due to lack of adequate clinical details) and 6% developed a biphasic response. Serial tryptase measurements were not available in 117 (69%) of the cohort. 97 (57%) patients were referred for specialist assessment, and 72 (74%) attended. 50% of cases were diagnosed with idiopathic systemic reactions/anaphylaxis and 28%, 14% and 8% triggered by drugs, foods and other allergies including disorders of mast cell overload, respectively. A weak positive correlation was detected between acute serum tryptase and severity. CONCLUSIONS The correlation between acute serum tryptase and severity of anaphylaxis/systemic reactions is weak. A significant proportion of patients with raised acute serum tryptase had mild reactions which did not meet WAO criteria for anaphylaxis and this may reduce the specificity of the test. The commonest aetiology in this cohort was idiopathic followed by drug and food allergies. NICE guidelines relating to serial tryptase measurements and specialist referral were not followed, and there is an urgent need to raise the awareness among clinicians involved in the management of anaphylaxis