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.

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.

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.

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.

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.

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.

102 Process Evaluation Exploring the Delivery and Uptake of Posture and Mobility Training for Staff in Care Homes

Introduction

Provision of care for care home residents with complex needs is challenging. Physiotherapists can play a major role in enhancing the confidence, skills and abilities of care home staff. The Skilful Care Training Package (SCTP) aims to provide staff with an understanding of good posture and training in skilled facilitation of movement. This process evaluation explored barriers and facilitators to delivery and uptake of the SCTP within the context of a feasibility cluster randomised controlled trial (cRCT) in 10 care homes.

Methods

A mixed methods process evaluation, incorporating non-participant observations and interviews, conducted in the five care homes receiving the SCTP intervention. Interviews were audio recorded and transcribed verbatim; resident conversations were captured via a Dictaphone and/or field-notes. Data analysis used the Framework approach.

Results

Fourteen staff training sessions were observed. Interviews with 22 staff and four trainers, and 13 conversations with residents were completed. Five factors influenced delivery and uptake of the SCTP:Organisational factors: strategies to publicise and facilitate access to training improved attendance; a convenient training location and trainer flexibility encouraged attendance and staff engagement.Intervention delivery: a practical participatory element to the training was highly valued; adapting the training to meet the needs of the homes was well-received.Engagement and interaction: relating training to workplace and residents’ experiences engaged staff; high levels of engagement and positive interaction within the training sessions were reported; challenges relating to staff hierarchy affected training delivery in some homes.Intervention content: posture and mobility elements were seen as important; however, some repetition with prior training was highlighted.Training impact: there were indications that staff adopted SCTP techniques. Staff reported an increase in their wellbeing and confidence in movement facilitation; cascade training was reported in some homes.

Conclusions

Training was well-received, and feedback on its impact was largely positive. Practical elements were viewed favourably over classroom-based learning. Intervention content should be revised to optimise focus and avoid overlap with other training.

Triage Into the Community for COVID-19 (TICC-19) Patients Pathway - Service evaluation of the virtual monitoring of patients with COVID pneumonia

INTRODUCTION

COVID-19 pneumonia presented a unique problem for healthcare systems with the potential to overwhelm hospitals and lead to unnecessary morbidity and mortality. Safe triage and follow up systems are required to manage this unprecedented demand.

METHODS

We designed a pathway for the triage and assessment of patients based on their resting oxygen saturations and response to a 30 metre rapid walking test. We admitted patients to a 'Virtual Ward' for remote oximetry monitoring from the Emergency Department, step down from inpatient wards and from the local Primary Care 'Hot Hub'. This allowed the safe and managed readmission of those patients who deteriorated at home.

RESULTS

During the first wave of COVID-19 we entered 273 onto the pathway for Virtual Ward follow up. Of these, 31 patients were readmitted to hospital, two were admitted to Intensive Care and one patient died. Median oxygen saturation at presentation was 97 % (IQR 96-98%) and following a 30 metre walk test 96% (IQR 94-97%). Median NEWS-2 score was 2 (IQR 1-3). On feedback 99.5% of patients were likely or extremely likely to recommend the service to their family and friends. There was a cost avoidance of £107,600 per month.

CONCLUSION

It is safe, feasible and cost effective to set up a triage system with remote oximetry monitoring for patients with COVID-19 and overwhelmingly patients find it a positive experience.

Validation of Two Commercial Lateral Flow Devices for the Detection of Peanut Proteins in Cookies: Interlaboratory Study

Results are reported for an interlaboratory validation study of 2 commercially available lateral flow devices (dipstick tests) designed to detect peanut residues in food matrixes. The test samples used in this study were cookies containing peanuts at 7 different concentrations in the range of 030 mg peanuts/kg food matrix. The test samples with sufficient and proven homogeneity were prepared in our laboratory. The analyses of the samples (5 times per level by each laboratory) were performed by 18 laboratories worldwide, which submitted a total of 1260 analytical results. One laboratory was found to be an outlier for one of the test kits. In general, both test kits performed well. However, some false-negative results were reported for all matrixes containing &lt;21 mg peanuts/kg cookie. It must be stressed that the test kits were challenged beyond their cut-off limits (5 mg/kg, depending on the food matrix). One test kit showed fewer false-negative results, but it led to some false-positive results for the blank materials. The sensitivity of the dipstick tests approaches that achieved with enzyme-linked immunosorbent assays.

Modification of Enrichment Protocols for TECRA Listeria Visual Immunoassay Method 995.22: Collaborative Study

A collaborative study was conducted to validate new enrichment methods for the TECRA Listeria Visual Immunoassay (TLVIA). These new methods incorporate a newly formulated medium, TECRA Listeria Enrichment Broth, which does not contain the highly toxic antifungal agent, cycloheximide. The new procedures will provide an alternative to the enrichment procedures described in AOAC Method 995.22. Three food types (raw ground beef, lettuce, and ice cream) were analyzed in the United States, and 2 food types (cooked turkey and cooked fish fillets) were analyzed in Australasia. Thirty collaborators participated in the study, 16 in Australasia and 14 in the United States. With the exception of one batch of ground beef, comparison of the proportion of positive test portions (p ≥ 0.05) showed no significant difference between the TLVIA and the reference method for the 5 foods at 3 inoculation levels. For the one batch of naturally contaminated raw ground beef, the TLVIA gave significantly more confirmed positive results than the reference method.

Abstract P3-03-11: Intraoperative assessment of the sentinel node in breast cancer by one step nucleic acid assay: Experience of over 1100 patients

Introduction

The intraoperative assessment of the sentinel node in women with breast cancer enables an immediate axillary node clearance to be done as part of the same operative procedure if the sentinel node is positive. This has significant benefits for the Patient, the Surgeon and the Health Care Provider. There are a variety of methods for the intra-operative assessment of the sentinel node which include: Touch Imprint Cytology, Frozen Section Analysis and Polymerase Chain Reaction (PCR) based molecular assays. OSNA is an automated molecular assay using a Polymerase Chain Reaction (PCR), which detects the presence of cytokeratin 19 in the sentinel node. We report our experience of OSNA for the intraoperative assessment of the sentinel node in our institution with 1148 patients.

Methods

All patients with operable breast cancer who were found to be node negative on clinical and radiological assessment of the axilla, and who had their axilla staged by a sentinel node biopsy at the Breast Unit at Warwick Hospital, UK over a 7 year period were included in this study. Data was collected from a prospective database maintained at the Breast Unit. The axillary node positivity rate and the number of patients with macrometastatic and micrometastatic disease as detected by OSNA was collected and compared with a group of 411 patients who had the intraoperative assessment by Touch Imprint Cytology and final histology by conventional Haematoxylin & Eosin (H&E) assessment, prior to the introduction of OSNA. The Chi-square test were used for statistical significance.

Results

1148 patients had their sentinel node assessed intraoperatively using OSNA in this 7 year study period. The sentinel node was positive in 376 patients (32.8%). Of those who had a positive node, 183 (15.9%) had macro-metastatic disease and 193 (16.8%) had micro-metastatic disease. When compared to 411 patients in the pre-OSNA period, that were assessed by Touch Imprint Cytology and H&E sections, the node positivity rate increased from 23.8% to 32.8% (p&lt;0.05) with the introduction of OSNA. Whilst there was no significant increase in the rate of macrometastatic disease – 20.4% versus 15.9 % ( p0.038), there was a significant increase in the patients who had micrometastases detected on OSNA - 3.4% versus 16.8 % ( p&lt;0.05) as shown in the table.

Conclusion

Our results demonstrate that OSNA is a more sensitive test for picking up metastatic disease, especially micrometastatic disease, in the sentinel node. Whilst this did cause some anxiety initially, the results of recent trials like ACSOG Z-11 and IBCSG 23-01 have shown that small volume disease or micrometastases in the sentinel node do not require an axillary node clearance. Intraoperative assessment of the sentinel node with OSNA significantly upstages the axillary nodal status, especially with regard to micrometastatic disease, but the ability to proceed to an axillary node clearance at the same operation as the sentinel node biopsy, still has significant advantages for the Patient, Surgeon and Health Care Providers.

Citation Format: Clarke D, Sinha A, Ion L, Weston S, Jones L, Kham M, Harries S. Intraoperative assessment of the sentinel node in breast cancer by one step nucleic acid assay: Experience of over 1100 patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-11.