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Nature Metabolism Aug 2022Measurement of oxygen consumption is a powerful and uniquely informative experimental technique. It can help identify mitochondrial mechanisms of action following... (Review)
Review
Measurement of oxygen consumption is a powerful and uniquely informative experimental technique. It can help identify mitochondrial mechanisms of action following pharmacologic and genetic interventions, and characterize energy metabolism in physiology and disease. The conceptual and practical benefits of respirometry have made it a frontline technique to understand how mitochondrial function can interface with-and in some cases control-cell physiology. Nonetheless, an appreciation of the complexity and challenges involved with such measurements is required to avoid common experimental and analytical pitfalls. Here we provide a practical guide to oxygen consumption measurements covering the selection of experimental models and instrumentation, as well as recommendations for the collection, interpretation and normalization of data. These guidelines are provided with the intention of aiding experimental design and enhancing the overall reputability, transparency and reliability of oxygen consumption measurements.
Topics: Energy Metabolism; Mitochondria; Oxygen Consumption; Reference Standards; Reproducibility of Results
PubMed: 35971004
DOI: 10.1038/s42255-022-00619-4 -
British Journal of Health Psychology Sep 2020Objectives The Capabilities, Opportunities, Motivations, Behaviour (COM-B) model is being used extensively to inform intervention design, but there is no standard...
Objectives The Capabilities, Opportunities, Motivations, Behaviour (COM-B) model is being used extensively to inform intervention design, but there is no standard measure with which to test the predictive validity of COM or to assess the impact of interventions on COM. We describe the development, reliability, validity, and acceptability of a generic 6-item self-evaluation COM questionnaire. Design and methods The questionnaire was formulated by behaviour change experts. Acceptability was tested in two independent samples of health care professionals (N = 13 and N = 85, respectively) and a sample of people with low socio-economic status (N = 214). Acceptability (missing data analyses and user feedback), reliability (test-retest reliability and Bland-Altman plots) and validity (floor and ceiling effects, Pearson's correlation coefficient [r], exploratory factor analysis [EFA], and confirmatory factor analysis [CFA] were tested using a national survey of 1,387 health care professionals. Results The questionnaire demonstrated acceptability (missing data for individual items: 5.9-7.7% at baseline and 18.1-32.5% at follow-up), reliability (ICCs .554-.833), and validity (floor effects 0.6-5.5% and ceiling effects 4.1-22.9%; pairwise correlations rs significantly <1.0). The regression models accounted for between 21 and 47% of the variance in behaviour. CFA (three-factor model) demonstrated a good model fit, (χ [6] = 7.34, p = .29, RMSEA = .02, CFI = .99, TLI = .99, BIC = 13,510.420, AIC = 13,428.067). Conclusions The novel six-item questionnaire shows evidence of acceptability, validity, and reliability for self-evaluating capabilities, opportunities, and motivations. Future research should aim to use this tool in different populations to obtain further support for its reliability and validity. Statement of contribution What is already known on the subject? The Capability, Opportunity, Motivation (COM), Behaviour (-B) model is being used extensively to inform intervention design. The lack of an accepted universal measure hinders progress in behaviour change. What does this study add? There is evidence of acceptability, validity, and reliability for self-evaluating COM. Our measure may be sufficiently generic for any behaviour or population, although this requires further testing.
Topics: Factor Analysis, Statistical; Humans; Motivation; Psychometrics; Reproducibility of Results; Surveys and Questionnaires; Weights and Measures
PubMed: 32314500
DOI: 10.1111/bjhp.12417 -
European Biophysics Journal : EBJ May 2021Analytical ultracentrifugation (AUC) is based on the concept of recording and analyzing macroscopic macromolecular redistribution that results from a centrifugal force...
Analytical ultracentrifugation (AUC) is based on the concept of recording and analyzing macroscopic macromolecular redistribution that results from a centrifugal force acting on the mass of suspended macromolecules in solution. Since AUC rests on first principles, it can provide an absolute measurement of macromolecular mass, sedimentation and diffusion coefficients, and many other quantities, provided that the solvent density and viscosity are known, and provided that the instrument is properly calibrated. Unfortunately, a large benchmark study revealed that many instruments exhibit very significant systematic errors. This includes the magnification of the optical detection system used to determine migration distance, the measurement of sedimentation time, and the measurement of the solution temperature governing viscosity. We have previously developed reference materials, tools, and protocols to detect and correct for systematic measurement errors in the AUC by comparison with independently calibrated standards. This 'external calibration' resulted in greatly improved precision and consistency of parameters across laboratories. Here we detail the steps required for calibration of the different data dimensions in the AUC. We demonstrate the calibration of three different instruments with absorbance and interference optical detection, and use measurements of the sedimentation coefficient of NISTmAb monomer as a test of consistency. Whereas the measured uncorrected sedimentation coefficients span a wide range from 6.22 to 6.61 S, proper calibration resulted in a tenfold reduced standard deviation of sedimentation coefficients. The calibrated relative standard deviation and mean error of 0.2% and 0.07%, respectively, is comparable with statistical errors and side-by-side repeatability in a single instrument.
Topics: Calibration; Macromolecular Substances; Solvents; Ultracentrifugation; Viscosity
PubMed: 33398460
DOI: 10.1007/s00249-020-01485-2 -
Critical Care (London, England) Nov 2019Excessive respiratory muscle effort during mechanical ventilation may cause patient self-inflicted lung injury and load-induced diaphragm myotrauma, but there are no...
BACKGROUND
Excessive respiratory muscle effort during mechanical ventilation may cause patient self-inflicted lung injury and load-induced diaphragm myotrauma, but there are no non-invasive methods to reliably detect elevated transpulmonary driving pressure and elevated respiratory muscle effort during assisted ventilation. We hypothesized that the swing in airway pressure generated by respiratory muscle effort under assisted ventilation when the airway is briefly occluded (ΔP) could be used as a highly feasible non-invasive technique to screen for these conditions.
METHODS
Respiratory muscle pressure (P), dynamic transpulmonary driving pressure (ΔP, the difference between peak and end-expiratory transpulmonary pressure), and ΔP were measured daily in mechanically ventilated patients in two ICUs in Toronto, Canada. A conversion factor to predict ΔP and P from ΔP was derived and validated using cross-validation. External validity was assessed in an independent cohort (Nanjing, China).
RESULTS
Fifty-two daily recordings were collected in 16 patients. In this sample, P and ΔP were frequently excessively high: P exceeded 10 cm HO on 84% of study days and ΔP exceeded 15 cm HO on 53% of study days. ΔP measurements accurately detected P > 10 cm HO (AUROC 0.92, 95% CI 0.83-0.97) and ΔP > 15 cm HO (AUROC 0.93, 95% CI 0.86-0.99). In the external validation cohort (n = 12), estimating P and ΔP from ΔP measurements detected excessively high P and ΔP with similar accuracy (AUROC ≥ 0.94).
CONCLUSIONS
Measuring ΔP enables accurate non-invasive detection of elevated respiratory muscle pressure and transpulmonary driving pressure. Excessive respiratory effort and transpulmonary driving pressure may be frequent in spontaneously breathing ventilated patients.
Topics: Acute Lung Injury; Aged; Female; Humans; Male; Middle Aged; Monitoring, Physiologic; Noninvasive Ventilation; Pressure; Respiration, Artificial; Respiratory Muscles; Weights and Measures; Work of Breathing
PubMed: 31694692
DOI: 10.1186/s13054-019-2617-0 -
Critical Care (London, England) Nov 2020Clinical practice guidelines recommend performing a cuff leak test in mechanically ventilated adults who meet extubation criteria to screen those at high risk for... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Clinical practice guidelines recommend performing a cuff leak test in mechanically ventilated adults who meet extubation criteria to screen those at high risk for post-extubation stridor. Previous systematic reviews demonstrated excellent specificity of the cuff leak test but disagreed with respect to sensitivity. We conducted a systematic review and meta-analysis to assess the diagnostic accuracy of the cuff leak test for predicting post-extubation airway complications in intubated adult patients in critical care settings.
METHODS
We searched Medline, EMBASE, Scopus, ISI Web of Science, the Cochrane Library for eligible studies from inception to March 16, 2020, without language restrictions. We included studies that examined the diagnostic accuracy of cuff leak test if post-extubation airway obstruction after extubation or reintubation was explicitly reported as the reference standard. Two authors in duplicate and independently assessed the risk of bias using the Quality Assessment for Diagnostic Accuracy Studies-2 tool. We pooled sensitivities and specificities using generalized linear mixed model approach to bivariate random-effects meta-analysis. Our primary outcomes were post-extubation airway obstruction and reintubation.
RESULTS
We included 28 studies involving 4493 extubations. Three studies were at low risk for all QUADAS-2 risk of bias domains. The pooled sensitivity and specificity of cuff leak test for post-extubation airway obstruction were 0.62 (95% CI 0.49-0.73; I = 81.6%) and 0.87 (95% CI 0.82-0.90; I = 97.8%), respectively. The pooled sensitivity and specificity of the cuff leak test for reintubation were 0.66 (95% CI 0.46-0.81; I = 48.9%) and 0.88 (95% CI 0.83-0.92; I = 87.4%), respectively. Subgroup analyses suggested that the type of cuff leak test and length of intubation might be the cause of statistical heterogeneity of sensitivity and specificity, respectively, for post-extubation airway obstruction.
CONCLUSIONS
The cuff leak test has excellent specificity but moderate sensitivity for post-extubation airway obstruction. The high specificity suggests that clinicians should consider intervening in patients with a positive test, but the low sensitivity suggests that patients still need to be closely monitored post-extubation.
Topics: Adult; Airway Extubation; Humans; Predictive Value of Tests; Pressure; Sensitivity and Specificity; Weights and Measures
PubMed: 33160405
DOI: 10.1186/s13054-020-03358-8 -
Medicine Aug 2021Early diagnosis as well as treatment is important in management of congenital muscular torticollis (CMT). The purpose of this study was to find an effective physical...
Effect of physical therapy intervention on thickness and ratio of the sternocleidomastoid muscle and head rotation angle in infants with congenital muscular torticollis: A randomized clinical trial (CONSORT).
BACKGROUND
Early diagnosis as well as treatment is important in management of congenital muscular torticollis (CMT). The purpose of this study was to find an effective physical therapy modality to improve the sternocleidomastoid (SCM) muscle thickness, the ratio of the SCM muscle thickness on the affected side to that on the non-affected side (A/N ratio), and head rotation in infant under 3 months of age diagnosed with CMT.
METHODS AND ANALYSIS
A single-blind, randomized clinical trial was conducted. Participants were assigned in one of the 3 study groups through randomization. The treatment was performed 3 times a week for 30 minutes until the head tilt was ≤5 degrees. Group 1 was treated by handling for active or active-assist movement, group 2 was treated with passive stretching, and group 3 was treated with thermotherapy. For general characteristics, a χ2 test and 1-way analysis of variance were used. Intragroup differences were analyzed using a paired t test, and intergroup differences were analyzed using an age-adjusted analysis of covariance.
RESULTS
After the intervention, there was no significant difference between groups in terms of SCM thickness on the affected side and A/N ratio (P > .05). Degree of head rotation on the affected side showed significant differences between groups (P < .05), with Group 2 showing significantly better results than group 1 and group 3 (P < .05, both).
CONCLUSION
Passive stretching treatment was more effective than other treatments of this study for improvement in degree of head rotation in CMT infants under 3 months of age.
TRIAL REGISTRATION
The trial is registered at the Institutional Review Board of Sahmyook University (IRB number, 2-7001793-AB-N-012019103HR) and the Clinical Research Information Service (CRiS; registry number, KCT0004862).
Topics: Humans; Infant; Muscles; Physical Therapy Modalities; Single-Blind Method; Sternum; Torticollis; Weights and Measures
PubMed: 34414985
DOI: 10.1097/MD.0000000000026998 -
Scientific Reports Apr 2022Electrochemical aptamer-based (EAB) sensors support the real-time, high frequency measurement of pharmaceuticals and metabolites in-situ in the living body, rendering...
Electrochemical aptamer-based (EAB) sensors support the real-time, high frequency measurement of pharmaceuticals and metabolites in-situ in the living body, rendering them a potentially powerful technology for both research and clinical applications. Here we explore quantification using EAB sensors, examining the impact of media selection and temperature on measurement performance. Using freshly-collected, undiluted whole blood at body temperature as both our calibration and measurement conditions, we demonstrate accuracy of better than ± 10% for the measurement of our test bed drug, vancomycin. Comparing titrations collected at room and body temperature, we find that matching the temperature of calibration curve collection to the temperature used during measurements improves quantification by reducing differences in sensor gain and binding curve midpoint. We likewise find that, because blood age impacts the sensor response, calibrating in freshly collected blood can improve quantification. Finally, we demonstrate the use of non-blood proxy media to achieve calibration without the need to collect fresh whole blood.
Topics: Aptamers, Nucleotide; Calibration; Vancomycin
PubMed: 35365672
DOI: 10.1038/s41598-022-09070-7 -
AMIA Joint Summits on Translational... 2021Global standardization of outcome measures for disease states can help researchers and healthcare providers compare healthcare institutions' and populations' health... (Review)
Review
Global standardization of outcome measures for disease states can help researchers and healthcare providers compare healthcare institutions' and populations' health outcomes. Despite the creation of standardized outcome sets, clinical institutions' adoption of these sets is not common. A literature review shows that among the challenges to standardizing outcome measures include the difficulties of achieving consensus in the working groups creating these outcome sets, the tradeoffs made when selecting outcome measurement tools, and the high costs of implementing a new or different set of outcome measures. The duplication of effort to create these standard sets can also limit standardization, which could be minimized through increased transparency of how these standard sets are developed. We propose some approaches to improve how to create and implement standard sets to broaden their usability across institutions.
Topics: Consensus; Delivery of Health Care; Humans; Outcome Assessment, Health Care; Reference Standards
PubMed: 34457155
DOI: No ID Found -
Journal of Clinical Monitoring and... Feb 2021Any measurement is always afflicted with some degree of uncertainty. A correct understanding of the different types of uncertainty, their naming, and their definition is... (Review)
Review
Any measurement is always afflicted with some degree of uncertainty. A correct understanding of the different types of uncertainty, their naming, and their definition is of crucial importance for an appropriate use of measuring instruments. However, in perioperative and intensive care medicine, the metrological requirements for measuring instruments are poorly defined and often used spuriously. The correct use of metrological terms is also of crucial importance in validation studies. The European Union published a new directive on medical devices, mentioning that in the case of devices with a measuring function, the notified body is involved in all aspects relating to the conformity of the device with the metrological requirements. It is therefore the task of the scientific societies to establish the standards in their area of expertise. Adopting the same understandings and definitions among clinicians and scientists is obviously the first step. In this metrologic review (part 1), we list and explain the most important terms defined by the International Bureau of Weights and Measures regarding quantities and units, properties of measurements, devices for measurement, properties of measuring devices, and measurement standards, with specific examples from perioperative and intensive care medicine.
Topics: Critical Care; Humans; Reference Standards
PubMed: 32185615
DOI: 10.1007/s10877-020-00494-y -
Clinical Chemistry and Laboratory... Apr 2023Biological variation (BV) data have many applications in laboratory medicine. However, these depend on the availability of relevant and robust BV data fit for purpose.... (Review)
Review
Biological variation (BV) data have many applications in laboratory medicine. However, these depend on the availability of relevant and robust BV data fit for purpose. BV data can be obtained through different study designs, both by experimental studies and studies utilizing previously analysed routine results derived from laboratory databases. The different BV applications include using BV data for setting analytical performance specifications, to calculate reference change values, to define the index of individuality and to establish personalized reference intervals. In this review, major achievements in the area of BV from last decade will be presented and discussed. These range from new models and approaches to derive BV data, the delivery of high-quality BV data by the highly powered European Biological Variation Study (EuBIVAS), the Biological Variation Data Critical Appraisal Checklist (BIVAC) and other standards for deriving and reporting BV data, the EFLM Biological Variation Database and new applications of BV data including personalized reference intervals and measurement uncertainty.
Topics: Humans; Reference Values; Reference Standards; Checklist
PubMed: 36537071
DOI: 10.1515/cclm-2022-1255