Abstract
Improvements in cost and speed of next generation sequencing (NGS) have provided a new pathway for delivering disease diagnosis, molecular typing, and detection of antimicrobial resistance ...(AMR). Numerous published methods and protocols exist, but a lack of harmonisation has hampered meaningful comparisons between results produced by different methods/protocols vital for global genomic diagnostics and surveillance. As an exemplar, this study evaluated the sensitivity and specificity of five well-established in-silico AMR detection software where the genotype results produced from running a panel of 436
Escherichia coli
were compared to their AMR phenotypes, with the latter used as gold-standard. The pipelines exploited previously known genotype–phenotype associations. No significant differences in software performance were observed. As a consequence, efforts to harmonise AMR predictions from sequence data should focus on: (1) establishing universal minimum to assess performance thresholds (e.g. a control isolate panel, minimum sensitivity/specificity thresholds); (2) standardising AMR gene identifiers in reference databases and gene nomenclature; (3) producing consistent genotype/phenotype correlations. The study also revealed limitations of in-silico technology on detecting resistance to certain antimicrobials due to lack of specific fine-tuning options in bioinformatics tool or a lack of representation of resistance mechanisms in reference databases. Lastly, we noted user friendliness of tools was also an important consideration. Therefore, our recommendations are timely for widespread standardisation of bioinformatics for genomic diagnostics and surveillance globally.
Hypothermia and hypothermic preconditioning are known to be profoundly cardioprotective, but the molecular mechanisms of this protection have not been fully explained. In this study, temperature ...preconditioning (16 °C) was found to be cardioprotective in isolated adult rat ventricular myocytes, enhancing contractile recovery and preventing calcium dysregulation after oxidative stress. Hypothermic preconditioning preserved mitochondrial function by delaying the pathological opening of the mitochondrial permeability transition pore (mPTP), whereas transient mPTP flickering remained unaltered. For the first time, reactive oxygen species (ROS) from the mitochondria are shown to be released exclusively during the hypothermic episodes of the temperature-preconditioning protocol. Using a mitochondrially targeted ROS biosensor, ROS release was shown during the brief bursts to 16 °C of temperature preconditioning. The ROS scavenger N-(2-mercaptopropionyl) glycine attenuated ROS accumulation during temperature preconditioning, abolishing the protective delay in mPTP opening. Temperature preconditioning induces ROS-dependant phosphorylation of the prosurvival kinase extracellular signal-regulated kinase (ERK)1/2. ERK1/2 activation was shown to be downstream of ROS release, as the presence of a ROS scavenger during temperature preconditioning completely blocked ERK1/2 activation. The cardioprotective effects of temperature preconditioning on mPTP opening were completely lost by inhibiting ERK1/2 activation. Thus, mitochondrial ROS release and ERK1/2 activation are both necessary to signal the cardioprotective effects of temperature preconditioning in cardiac myocytes.
The proximal musculo‐tendinous junction (MTJ) is a common site of hamstring strain injury but the anatomy of this region is not well defined. A morphometric analysis of the proximal MTJs of biceps ...femoris long head (BFlh), semitendinosus (ST), and semimembranosus (SM) was undertaken from dissection of 10 thighs from five male cadavers and magnetic resonance imaging of 20 thighs of 10 active young men. The length, volume, and cross‐sectional area of the proximal tendon, MTJ and muscle belly, and muscle‐tendon interface area were calculated. In both groups, MTJs were reconstructed three‐dimensionally. The proximal tendons and MTJs were expansive, particularly within SM and BFlh. Morphology varied between muscles although length measurements within individual muscles were similar in cadavers and young men. Semimembranosus had the longest proximal tendon (cadavers: mean 33.6 ± 2.0 cm; young men: mean 31.7 ± 1.6 cm) and MTJ (>20 cm in both groups) and the greatest muscle‐tendon interface area, followed by BFlh and ST. Mean muscle belly volumes were more than three times greater in young men than elderly male cadavers (P < 0.001). These unique morphometric data contribute to a better understanding of hamstring anatomy, an important factor in the pathogenesis of hamstring strain injury.
We utilize recently introduced chemically specific but coarse-grained models of poly(ethylene oxide) (PEO) and poly(methyl methacrylate) (PMMA) to explore the influence of monomer architecture on ...the dynamics of supported thin polymer films based on molecular dynamics simulations. In particular, we contrast differences in the molecular packing and mobility gradients in these materials near the substrate and “free” interface regions. As expected, relaxation is generally enhanced in the free surface region relative to the film interior (and bulk), and the degree of enhancement is similar for both PEO and PMMA. However, the dynamical changes near the substrate are more sensitive to monomer structure, and are enhanced with increasing polymer–substrate interaction strength, ε. PMMA is relatively stiff compared to PEO and has a side group of appreciable size, and we find that the dynamics of PMMA near the substrate are slowed significantly more in comparison to PEO for the same substrate. Substrate interactions lead to a notable difference of local fragility near the substrate that appears to arise from a higher cohesive interaction strength of the PMMA chains in this region. Our data also reveal the inadequacy of the these coarse-grained polymer models to reproduce the experimentally known differences in the fragility of these materials. However, this technical shortcoming is not expected to alter our qualitative conclusions regarding the comparative effect of substrate interactions on relatively flexible polymers such as PEO versus a relatively stiff polymer such as PMMA.
Raman microspectroscopy was applied to monitor the intracellular redox state of myoglobin and cytochrome c from isolated adult rat cardiomyocytes during hypoxia and reoxygenation. The nitrite ...reductase activity of myoglobin leads to the production of nitric oxide in cells under hypoxic conditions, which is linked to the inhibition of mitochondrial respiration. In this work, the subsequent reoxygenation of cells after hypoxia is shown to lead to increased levels of oxygen-bound myoglobin relative to the initial levels observed under normoxic conditions. Increased levels of reduced cytochrome c in ex vivo cells are also observed during hypoxia and reoxygenation by Raman microspectroscopy. The cellular response to reoxygenation differed dramatically depending on the method used in the preceding step to create hypoxic conditions in the cell suspension, where a chemical agent, sodium dithionite, leads to reduction of cytochromes in addition to removal of dissolved oxygen, and bubbling-N2 gas leads to displacement of dissolved oxygen only. These results have an impact on the assessment of experimental simulations of hypoxia in cells. The spectroscopic technique employed in this work will be used in the future as an analytical method to monitor the effects of varying levels of oxygen and nutrients supplied to cardiomyocytes during either the preconditioning of cells or the reperfusion of ischaemic tissue.
Previous analyses have suggested variations in cervical spine canal morphology according to ethnicity, possibly in part due to variations in the posterior elements. The potential for these variations ...to affect the placement of instrumentation is uncertain. The aim of this study was to report on the feasibility of C2 lamina screw insertion in a New Zealand cohort including analysis of Māori, the indigenous people of New Zealand.
A trauma computed tomography database was accessed to identify suitable images. On axial images, where the isthmus was at its widest, the outer diameter (OD) and inner diameter (ID) of the lamina were measured. Screw length was measured from a proposed entry point to the contralateral junction of the lamina and lateral mass. The spinolaminar angle was measured as the angle subtended by the screw trajectory and midsagittal plane. A 5.5-mm OD was accepted as a threshold for the feasibility of lamina screw placement.
One hundred eighty-seven images were assessed: 115 New Zealand European and 72 Māori. The mean age of the cohort was 41.9 years (SD 19.6), and most patients (64%) were men. For the entire cohort, mean OD was 6.6 and 6.8 mm on the right and left, respectively; the mean inner diameter was 3.5 and 3.8 mm; mean screw length was 31.5 and 31.5 mm; and mean spinolaminar angle was 46.0° and 46.1°. C2 lamina screw placement was feasible in a majority of patients. Considering only Māori patients, placement was feasible in 96% of right and 94% of left laminae in men but 72% of right and 72% of left laminae in women.
In a majority of patients, C2 lamina screw placement is feasible. However, advanced imaging must be carefully assessed preoperatively because data suggest that Māori women may not necessarily have optimal anatomy.
Care needs to be taken when assessing and planning surgery inpatients of different ethnicities because variations may exist in the morphology of the posterior elements of C2, leading to variation in optimal fixation strategy.
3.
Background
Emergent decompression, either by closed reduction or surgical decompression, of the acutely compressed cervical spinal cord is recognized as important in minimizing the neurological ...outcomes of these injuries. The aim of this study is to optimize New Zealand's capability to perform closed reductions.
Methods
Regional hospitals throughout New Zealand were surveyed on their capability to reduce acute cervical spine dislocations using traction. A systematic literature review was performed to investigate aspects of patient selection, reduction technique and the outcomes achieved with closed reduction of such injuries. This information was combined with our local experience to develop an evidence‐based guideline.
Results
Most (12/14) of the regional centres throughout New Zealand have recent experience, remain willing and have the resources necessary to reduce appropriate cervical spine injuries using traction. Fourteen published studies from nine countries detail a 75% success rate from 363 cases of attempted closed reduction, with the greatest neurological recovery noted in patients with shorter time period from injury to reduction. One patient suffered neurological worsening. The published protocols were compared and coupled with our local practice to create an online, step‐by‐step, evidence‐based reference to help clinicians in regional hospitals perform a safe and successful closed reduction.
Conclusion
To optimize the capability of inexperienced personnel to perform closed reductions in a safe and timely manner, we have developed an online, step‐by‐step, evidence‐based reference (www.closedreduction.co.nz). This forms part of New Zealand's strategy to achieve urgent cord decompression for appropriate cervical spinal cord injuries.
'Artifacts of Thinking: Reading Arendt’s 'Denktagebuch'' offers a path through Hannah Arendt’s recently published 'Denktagebuch', or 'Book of Thoughts.' In this book a number of innovative Arendt ...scholars come together to ask how we should think about these remarkable writings in the context of Arendt’s published writing and broader political thinking. Unique in its form, the 'Denktagebuch' offers brilliant insights into Arendt’s practice of thinking and writing. 'Artifacts of Thinking' provides an introduction to the 'Denktagebuch' as well as a glimpse of these fascinating but untranslated fragments that reveal not only Arendt’s understanding of “the life of the mind” but her true lived experience of it.
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