Static magnetic stimulation induces structural plasticity at the axon initial segment of inhibitory cortical neurons

Static magnetic stimulation (SMS) is a form of non-invasive brain stimulation that alters neural activity and induces neural plasticity that outlasts the period of stimulation. This can modify corticospinal excitability or motor behaviours, suggesting that SMS may alter the intrinsic excitability of neurons. In mammalian neurons, the axon initial segment (AIS) is the site of action potential initiation and undergoes structural plasticity (changes in length and position from the soma) as a homeostatic mechanism to counteract chronic changes in neuronal activity. We investigated whether the chronic application of SMS (6 and 48 h, 0.5 T) induces structural AIS plasticity in postnatally derived primary cortical neurons. Following 6 h of SMS, we observed a shortening in mean AIS length compared to control, that persisted 24 h post stimulation. In contrast, 48 h of SMS induced an immediate distal shift that persisted 24 h post-stimulation. Pharmacological blockade of voltage gated L/T-type calcium channels during stimulation did not prevent SMS-induced AIS structural plasticity. Our findings provide the foundation to expand the use of chronic SMS as a non-invasive method to promote AIS plasticity.

Biologics in peripheral ulcerative keratitis

Over the past two decades biologic therapies have seen a rapid uptake in the management of ocular inflammation. Peripheral ulcerative keratitis (PUK), once a harbinger of blindness and mortality in refractory rheumatological disease, is now increasingly being treated with these agents. We conducted a review to evaluate the evidence base for this application and to provide a road map for their clinical usage in PUK, including dosage and adverse effects. A literature search across Medline, Embase and Cochrane Database of Systematic Reviews was undertaken to identify all patients with PUK that were treated with a biologic in a peer viewed article. Overall, whilst the evidence base for biologic use in PUK was poor, reported cases demonstrate an increasingly powerful and effective role for biologics in refractory PUK. This was particularly the case for rituximab in PUK secondary to granulomatous with polyangiitis.

High-'n'-dry? A comparison of cannabis and alcohol use in drivers presenting to hospital after a vehicular collision

DESIGN

This was a prospective observational study.

BACKGROUND AND AIMS

The characteristics of cannabis-involved motor vehicle collisions are poorly understood. This study of injured drivers identifies demographic and collision characteristics associated with high tetrahydrocannabinol (THC) concentrations.

SETTING

The study was conducted in 15 Canadian trauma centres between January 2018 and December 2021.

CASES

The cases (n = 6956) comprised injured drivers who required blood testing as part of routine trauma care.

MEASUREMENTS

We quantified whole blood THC and blood alcohol concentration (BAC) and recorded driver sex, age and postal code, time of crash, crash type and injury severity. We defined three driver groups: high THC (THC ≥ 5 ng/ml and BAC = 0), high alcohol (BAC ≥ 0.08% and THC = 0) and THC/BAC-negative (THC = 0 = BAC). We used logistic regression techniques to identify factors associated with group membership.

FINDINGS

Most injured drivers (70.2%) were THC/BAC-negative; 1274 (18.3%) had THC > 0, including 186 (2.7%) in the high THC group; 1161 (16.7%) had BAC > 0, including 606 (8.7%) in the high BAC group. Males and drivers aged less than 45 years had higher adjusted odds of being in the high THC group (versus the THC/BAC-negative group). Importantly, 4.6% of drivers aged less than 19 years had THC ≥ 5 ng/ml, and drivers aged less than 19 years had higher unadjusted odds of being in the high THC group than drivers aged 45-54 years. Males, drivers aged 19-44 years, rural drivers, seriously injured drivers and drivers injured in single-vehicle, night-time or weekend collisions had higher adjusted odds ratios (aORs) for being in the high alcohol group (versus THC/BAC-negative). Drivers aged less than 35 or more than 65 years and drivers involved in multi-vehicle, daytime or weekday collisions had higher adjusted odds for being in the high THC group (versus the high BAC group).

CONCLUSIONS

In Canada, risk factors for cannabis-related motor vehicle collisions appear to differ from those for alcohol-related motor vehicle collisions. The collision factors associated with alcohol (single-vehicle, night-time, weekend, rural, serious injury) are not associated with cannabis-related collisions. Demographic factors (young drivers, male drivers) are associated with both alcohol and cannabis-related collisions, but are more strongly associated with cannabis-related collisions.

Abdominal stab wounds with retained knife: 15 years of experience from a major trauma centre in South Africa

INTRODUCTION

This study reviews our cumulative experience with the management of patients presenting with a retained knife following an abdominal stab wound (SW).

METHODS

A retrospective study was conducted at a major trauma centre in South Africa over a 15-year period from July 2006 to December 2020 including all patients who presented with a retained knife in the abdomen following a SW.

RESULTS

A total of 42 cases were included: 37 males (93%) with a mean age of 26 years. A total of 18 knives (43%) were in the anterior abdomen and 24 were posterior abdomen. Plain radiography was performed in 88% (37/42) of cases and computed tomography was performed in 81% (34/42); 90% (38/42) underwent extraction in the operating theatre. Laparotomy was performed in 62% (26/42). Of all the laparotomies performed, 77% (20/26) were positive for intra-abdominal organ or visceral injury. Overall morbidity was 31%. There were two mortalities (5%). Laparotomy was less commonly required for the posterior abdomen (33% (8/24) vs 100% (18/18), p<0.001). For retained knives in the anterior abdomen, 72% (13/18) of the laparotomies were positive for intra-abdominal organ or visceral injury. For the posterior abdomen, 7 of the 8 (88%) were positive for intra-abdominal organ or visceral injury. There were no differences in the need for intensive care unit admission, length of hospital stay, morbidities or mortalities.

CONCLUSIONS

Uncontrolled extraction of a retained knife in the abdomen outside of the operating theatre must be avoided. Retained knives in the anterior abdomen usually require formal laparotomy, but this is generally not required for posterior abdomen.

Substrate engineering of plasmonic nanocavity antenna modes

Plasmonic nanocavities have emerged as a promising platform for next-generation spectroscopy, sensing and photonic quantum information processing technologies, benefiting from a unique confluence of nanoscale compactness and integrability, ultrafast functionality and room-temperature viability. Harnessing their unprecedented optical field confinement and enhancement properties for such diverse application domains, however, demands continued innovation in cavity design and robust strategies for engineering their plasmonic mode characteristics, with the aim of optimizing spatial and spectral matching conditions for strong light-matter interaction involving embedded quantum emitters. Adopting the canonical gold bowtie nanoantenna, we show that the complex refractive index, n + ik, of the substrate material provides additional design flexibility in tailoring the properties of plasmonic nanocavity modes, including their resonance wavelengths, hotspot locations, intracavity field polarization and radiative decay rates. In particular, we predict that highly refractive (n ≥ 4) or highly absorptive (k ≥ 4) substrates provide two complementary approaches to engineering nanocavity modes that are especially desirable for coupling two-dimensional quantum materials, featuring namely an elevated hotspot with a dominantly in-plane polarized near-field, as well as a strongly radiative character. Our study elucidates the benefits and intricacies of a largely unexplored facet of nanocavity mode manipulation, beyond the widely practiced synthetic control over the cavity topology or physical dimensions, and paves the way for plasmonic cavity quantum electrodynamics with two-dimensional excitonic matter.

An audit of trauma laparotomy in children and adolescents highlights the role of damage control surgery and the need for a trauma systems approach to injury in this vulnerable population

BACKGROUND: This study reviews the indications and outcome of emergency laparotomy for paediatric trauma in a South African trauma centre. METHODS: This was a retrospective study of all children less than 18 years of age who underwent an emergency laparotomy for trauma between December 2012 and October 2020 at Grey's Hospital in Pietermaritzburg. RESULTS: During the eight-year period under review, a total of136 children of which 107 were male underwent a laparotomy for trauma. The median age was 14 years. There were 80 (57.1%) blunt mechanisms, and the rest were penetrating mechanisms. A total of 46 (33%) patients required ICU admission. Thirty-four patients developed a complication. These included nine cases of pneumonia, one case of renal failure, two patients developed abdominal collections, three wound-related complications, three neurological complications and one miscellaneous complication. There were seven (5%) deaths. The penetrating cohort were older than the blunt cohort. Solid viscera were more likely to be injured in the blunt cohort and hollow viscera more likely in the penetrating cohort. A total of 16 (11%) patients underwent damage control surgery (DCS). Of this cohort, there were three female children. Six sustained blunt trauma and ten penetrating trauma. A total of six (37%) of these children died. CONCLUSION: Emergency laparotomy for trauma in children is not infrequent in Pietermaritzburg and there is a high incidence of penetrating trauma in this cohort. The response to increased degrees of physiological derangement is the application of DCS. Ongoing efforts to develop and strengthen a paediatric trauma service appear to be justified.

Management of penetrating thoracic trauma with retained knife blade: 15-year experience from a major trauma centre in South Africa

INTRODUCTION

This study reviews our experience with the management a retained knife in the setting of thoracic stab wounds.

METHODS

A retrospective study was conducted at a major trauma in South Africa over a 15-year period from January 2004 to December 2018.

RESULTS

There were 40 patients, of whom 37 were males (93%). Median age was 24 years; 78% of cases (31 of 40) were a retained knife and 23% (9 of 40) were a retained blade. The locations of the stab wounds were 19 (48%) anterior and 21 (53%) posterior. Plain x-ray was performed in 85% (34) of patients and computed tomography angiography was performed in 85% (34). Six patients had haemodynamic instability and were expedited to the operating room without further imaging. Three of these had cardiac tamponade and three a massive haemothorax. Simple extraction and wound exploration were performed in 58% (23 of 40) of cases and the remaining 43% (17 of 40) required operative exploration and extraction. The operative approach was anterolateral thoracotomy in nine cases, posterolateral thoracotomy in four and median sternotomy in three cases. One patient required extraction and concurrent vertebral laminectomy due to cord compression. Twelve patients (30%) experienced complications (nine wound sepsis and three hospital-acquired pneumonia). There was one mortality (3%). The median length of hospital stay was 6 days.

CONCLUSION

Uncontrolled extraction of a retained thoracic knife outside the operating room must be avoided. An unstable patient should proceed directly for operative exploration. For stable patients, cross-sectional imaging will allow for planned extraction in operating room.

A Systematic Review and Narrative Synthesis of the Effectiveness of Peer- versus Faculty-led Simulation for Clinical Skills Acquisition in Undergraduate Student Nurses. MSc Project Findings

Background:

Clinical skills learning is an integral part of undergraduate nursing programmes in United Kingdom nurse education. Faculty staff teach some elements of clinical skills, and some are taught by clinicians in practice. International evidence indicates that some students feel overly anxious when taught by faculty members but less so with their peers, meaning that peer-led clinical skills teaching and learning might reduce anxiety and facilitate the acquisition and retention of skills education.

Objective:

The objective of this systematic review was to explore the research relating to undergraduate student nurses’ acquisition of skills within the simulation setting, particularly the associations between peer-led and lecturer-led learning.

Methods:

A systematic review of the literature was used to find all available evidence. A search of nine healthcare databases using Boolean and MeSH search terms including ‘Peer-to-peer’, ‘Clinical Skill*’, ‘Simulat*’, and ‘Student Nurs*’ was undertaken. Due to the heterogeneity of the research found, statistical meta-analysis was not possible, and so a narrative synthesis based on thematic analysis was conducted, which involved three-person research team critically appraising nine articles for inclusion in the review.

Results:

Articles were located from worldwide sources.

Three main themes in the findings were: psychological factors, motor skills, and educational issues. The use of peers can help to increase students’ motor skills, improved the psychological impact of skills and learning, and offered students a chance to be active participants in their education.

Conclusion:

Having explored the literature, we conclude that peer-to-peer teaching and learning could have a place in undergraduate nursing education; however, it is not clear if student nurses’ skills acquisition is more effective if mediated by peer- or lecturer-led teaching. Further research is required in this area to quantify and compare outcomes.

Antimicrobial stewardship in spinal cord injury: A multidisciplinary approach

Context: In a global environment of escalating antimicrobial resistance and limited new antibiotic development, there is a desire to optimize antibiotic use across all settings to preserve options for the future. Despite this, antibiotics continue to be prescribed inappropriately in many settings. Patients with a spinal cord injury (SCI) are particularly vulnerable to receiving multiple courses of antibiotics, yet there is limited data reviewing antimicrobial stewardship (AMS) programs in this patient population.Hypothesis: Adopting AMS rounds will reduce days of antibiotic treatment.Intervention: We implemented a systematic bedside AMS multidisciplinary team (MDT) ward round within the SCI Unit at our hospital, where a collaborative inter-speciality and inter-professional approach was undertaken to address antibiotic prescriptions. A retrospective audit of antibiotic prescriptions was performed one month prior and one month during the intervention.Outcome measures: An infectious disease consultant led a multidisciplinary, multispecialty ward rounding team, looking at antibiotic appropriateness and guideline compliance. The effectiveness of this intervention was assessed by retrospectively looking at antibiotic days of usage per patient day of occupancy.Results: Antibiotic consumption significantly decreased following the AMS intervention, from 69.8 to 24.3 days on treatment per 100 patient days (P < 0.001). Following implementation of the ward round the proportion of therapeutic guideline compliant prescriptions significantly rose from 18% in April to 56% in August (P < 0.001).Conclusions: Utilizing a collaborative inter-speciality and inter-professional AMS approach and providing face to face feedback about the appropriateness of antibiotic prescribing can help optimize antibiotic usage within a SCI unit.

The fractionation of phosphorus in UK chalk stream surface waters and its relevance to the regulation and management of water quality

The regulatory management of river water quality requires measurements of phosphorus that are operationally viable and meaningful in terms of insight into its effects. This need is a particular concern in globally rare and ecologically sensitive chalk streams. P data pertaining to rivers are commonly limited to soluble reactive P; other fractions of P may be of concern but are not routinely monitored. This study seeks to establish the nature and extent of non-regulated forms of P in UK chalk streams. Whilst soluble reactive P in two southern English chalk streams was found to comprise the majority of reactive P in surface waters in the majority of samples, 15-20% of the total reactive P was within other size fractions greater than 0.22 μm. The contribution of reactive P to the total P was highly variable. We conclude that, with some adjustments, the established method of regulatory monitoring of P in UK rivers is viable and valuable. In cases where the levels of reactive P are not consistent with ecological status and/or expected outcomes of programmes of measures, we recommend that targeted analysis of non-regulated forms of P is undertaken as a means to guide and focus management interventions.

The future of simulation-based medical education: Adaptive simulation utilizing a deep multitask neural network

BACKGROUND

In resuscitation medicine, effectively managing cognitive load in high-stakes environments has important implications for education and expertise development. There exists the potential to tailor educational experiences to an individual's cognitive processes via real-time physiologic measurement of cognitive load in simulation environments.

OBJECTIVE

The goal of this research was to test a novel simulation platform that utilized artificial intelligence to deliver a medical simulation that was adaptable to a participant's measured cognitive load.

METHODS

The research was conducted in 2019. Two board-certified emergency physicians and two medical students participated in a 10-minute pilot trial of a novel simulation platform. The system utilized artificial intelligence algorithms to measure cognitive load in real time via electrocardiography and galvanic skin response. In turn, modulation of simulation difficulty, determined by a participant's cognitive load, was facilitated through symptom severity changes of an augmented reality (AR) patient. A postsimulation survey assessed the participants' experience.

RESULTS

Participants completed a simulation that successfully measured cognitive load in real time through physiological signals. The simulation difficulty was adapted to the participant's cognitive load, which was reflected in changes in the AR patient's symptoms. Participants found the novel adaptive simulation platform to be valuable in supporting their learning.

CONCLUSION

Our research team created a simulation platform that adapts to a participant's cognitive load in real-time. The ability to customize a medical simulation to a participant's cognitive state has potential implications for the development of expertise in resuscitation medicine.

Printed monolith adsorption as an alternative to expanded bed adsorption for purifying M13 bacteriophage

An ordered 3D printed chromatography stationary phase was used to purify M13 bacteriophage (M13) directly from crude cell culture. This new approach, which offers the same advantages as expanded bed adsorption (EBA) with regard to tolerating solids-laden feed streams but without the corresponding issues associated with fluidized bed stability that affect the latter, can be described as "printed monolith adsorption (PMA)". PMA columns (5, 10 and 15 cm length by 1 cm diameter) were made via a wax templating method from cross-linked cellulose hydrogel and functionalized with a quaternary amine ligand. The recovery of M13 was found to be strongly linked to load flow rate, with the highest recovery 89.7% ± 6% for 1.4 × 10¹¹ pfu/mL of resin occurring at 76 cm/h with a 10 cm column length. A recovery of 87.7% ± 5% for 1.49 × 10¹¹ pfu/mL of media was achieved with a 15 cm column length under conditions comparable to a reported EBA process. The PMA process was completed three times faster than EBA because PMA flow rates can readily be adjusted during operation, with high flow rates and low back pressure, which is unique to the ordered monolithic media geometry used. Equilibration, wash, and cleaning steps were carried out at high flow rates (611 cm/h), minimizing process time and were limited only by the volumetric flow rate capacity of the pumps used, rather than column back pressure (<0.1 MPa at 611 cm/hr). Initial capture of M13 appears to occur on the surface of the monolith solid phase (i.e. the mobile phase channel walls) and subsequently, at a slower rate, within the internal pores of the solid phase media. The difference in binding rate between these two sites is likely caused by slow pore diffusion of the large M13 particles into the pores, with similar slow diffusion out of the pores resulting in tailing of the elution peak. The results indicate that PMA is a promising technology for the efficient purification of viruses directly from crude cell culture.

Neurovascular coupling and oxygenation are decreased in hippocampus compared to neocortex because of microvascular differences

The hippocampus is essential for spatial and episodic memory but is damaged early in Alzheimer's disease and is very sensitive to hypoxia. Understanding how it regulates its oxygen supply is therefore key for designing interventions to preserve its function. However, studies of neurovascular function in the hippocampus in vivo have been limited by its relative inaccessibility. Here we compared hippocampal and visual cortical neurovascular function in awake mice, using two photon imaging of individual neurons and vessels and measures of regional blood flow and haemoglobin oxygenation. We show that blood flow, blood oxygenation and neurovascular coupling were decreased in the hippocampus compared to neocortex, because of differences in both the vascular network and pericyte and endothelial cell function. Modelling oxygen diffusion indicates that these features of the hippocampal vasculature may restrict oxygen availability and could explain its sensitivity to damage during neurological conditions, including Alzheimer's disease, where the brain's energy supply is decreased.

Recent Developments in HLA B27 Anterior Uveitis

There has been steady progress in understanding the pathogenesis, clinical features, and effective treatment of acute anterior uveitis (AU) over the past 5 years. Large gene wide association studies have confirmed that AU is a polygenic disease, with overlaps with the seronegative arthropathies and inflammatory bowel diseases, associations that have been repeatedly confirmed in clinical studies. The role of the microbiome in AU has received increased research attention, with recent evidence indicating that human leukocyte antigen B27 (HLA B27) may influence the composition of the gut microbiome in experimental animals. Extensive clinical investigations have confirmed the typical features of acute AU (AAU) and its response to topical, regional and systemic immunosuppressive treatment. Increased understanding of the role of cytokines has resulted in studies confirming the value of anti-cytokine therapy [anti-tumor necrosis factor (anti-TNF) and interleukin 6 (IL-6) therapy] in severe and recurrent cases of AAU, particularly in subjects with an associated spondyloarthopathy (SpA) and in juvenile idiopathic arthritis (JIA)-associated AAU.

World Small Animal Veterinary Association Global Dental Guidelines

Dental, oral, and maxillofacial diseases are some of the most common problems in small animal veterinary practice. These conditions create significant pain as well as localized and potentially systemic infection. As such, the World Small Animal Veterinary Association (WSAVA) believes that un- and under treated oral and dental diseases pose a significant animal welfare concern. Dentistry is an area of veterinary medicine which is still widely ignored and is subject to many myths and misconceptions. Effective teaching of veterinary dentistry in the veterinary school is the key to progression in this field of veterinary medicine, and to the improvement of welfare for all our patients globally. These guidelines were developed to provide veterinarians with the information required to understand best practices for dental therapy and create realistic minimum standards of care. Using the three-tiered continuing education system of WSAVA, the guidelines make global equipment and therapeutic recommendations and highlight the anaesthetic and welfare requirements for small animal patients. This document contains information on common oral and dental pathologies, diagnostic procedures (an easily implementable and repeatable scoring system for dental health, dental radiography and radiology) and treatments (periodontal therapy, extractions). Further, there are sections on anaesthesia and pain management for dental procedures, home dental care, nutritional information, and recommendations on the role of the universities in improving veterinary dentistry. A discussion of the deleterious effects of anaesthesia free dentistry (AFD) is included, as this procedure is ineffective at best and damaging at worst. Throughout the document the negative effects of undiagnosed and/or treated dental disease on the health and well-being of our patients, and how this equates to an animal welfare issue, is discussed.

Microbiological assessment of liquid feed for finisher pigs on commercial pig units

AIMS

To investigate the microbiological and nutritional quality of liquid finisher pig feed on commercial production units and the factors influencing this.

METHODS AND RESULTS

Microbiological and physio-chemical analyses were performed on liquid feed sampled from the mixing tank and troughs of the finisher section of eight commercial pig units. Lactic acid bacteria, yeast and Escherichia coli counts, as well as lactic acid, ethanol and acetate concentrations were higher in residual feed sampled from the troughs compared with mixing tank samples (P < 0·001). Feed pH, as well as lysine, methionine and threonine concentrations and gross energy were all lower in the residual trough samples (P < 0·001). Liquid co-products reduced E. coli counts in the residual trough samples (P < 0·05), pH in the mixing tank (P < 0·01) and fresh trough samples (P < 0·05) and mould counts at all three sampling locations (P < 0·01) but sanitation practices had no impact.

CONCLUSIONS

Even when considered unfermented, a considerable degree of spontaneous fermentation occurs in liquid feed, with resultant negative effects on nutritional quality.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is one of the first studies showing that uncontrolled fermentation of fresh liquid pig feed is commonplace on commercial units, highlighting the need for implementation of suitable control strategies.

Wireless And Portable Daily Soundscape Monitoring System For Auditory Profiling: Diagnostic Tool For Alzheimer's Disease

The purpose of this paper is to develop an inexpensive, wearable, and portable monitoring system with wireless capabilities for signal acquisition of the user's surrounding soundscape and electroencephalography (EEG). The end-goal of this device is to monitor high-risk populations that are developing into earlier stages of Alzheimer's Disease (AD). Currently, the development of such device is still within preliminary phase and has only been tested in healthy individuals. Future applications of our monitoring system may be used as a non-invasive and inexpensive diagnostic tool for early detection of AD, potentially paving a new platform for therapeutic intervention. The system consists of low-weight bearing components, including an analog front-end and a single-board computer. The analog front-end contains three independent EEG, reference, bias, and auditory recording channels. The single-board computer timestamps and encrypts the incoming channels prior to local or "cloud" storage. Cloud storage provides ease-of-access and offline data analysis without the need to physically extract the data from the monitoring system. A portable/rechargeable battery provides power to the entire monitoring system for over 4 hours of operation. A graphical user-interface (GUI) was developed for secured remote access to data, parameter settings, and system configurations. The performance of the system was tested by measuring the frequency following response (FFR) in the captured EEG signals with respect to periodic auditory stimuli.