Müllerian anomalies in girls with congenital solitary kidney

BACKGROUND

The prevalence of Müllerian anomalies (MA) among patients with congenital solitary functioning kidney (SFK) is not well defined. A delay in diagnosis of obstructive MA can increase the risk of poor clinical outcomes. This study describes the prevalence of MA in patients with congenital SFK.

METHODS

A retrospective review was performed of patients within the Nationwide Children's Hospital system with ICD9 or ICD10 diagnostic codes for congenital SFK defined as either unilateral renal agenesis (URA) or multicystic dysplastic kidney (MCDK) and confirmed by chart review. Patients with complex urogenital pathology were excluded. Renal anomaly, MA, reason for and type of pelvic evaluation, and age of diagnosis of anomalies were evaluated.

RESULTS

Congenital SFK occurred in 431 girls due to URA (209) or MCDK (222). Pelvic evaluation, most commonly by ultrasound for evaluation of abdominal pain or dysmenorrhea, occurred in 115 patients leading to MA diagnosis in 60 instances. Among 221 patients ages 10 years and older, 104 underwent pelvic evaluation and 52 were diagnosed with an MA of which 20 were obstructive. Isolated uterine or combined uterine and vaginal anomalies were the most common MA. MA were five-fold more common in patients with URA compared to MCDK. In 75% of patients, the SFK was diagnosed prior to the MA.

CONCLUSIONS

The prevalence of MA in patients with congenital SFK was 24% among those age 10 years or older, and 38% were obstructive. This justifies routine screening pelvic ultrasound in girls with congenital SFK to improve early diagnosis.

Increasing Knockin Efficiency in Mouse Zygotes by Transient Hypothermia

Integration of a point mutation to correct or edit a gene requires the repair of the CRISPR-Cas9-induced double-strand break by homology-directed repair (HDR). This repair pathway is more active in late S and G2 phases of the cell cycle, whereas the competing pathway of nonhomologous end-joining (NHEJ) operates throughout the cell cycle. Accordingly, modulation of the cell cycle by chemical perturbation or simply by the timing of gene editing to shift the editing toward the S/G2 phase has been shown to increase HDR rates. Using a traffic light reporter in mouse embryonic stem cells and a fluorescence conversion reporter in human-induced pluripotent stem cells, we confirm that a transient cold shock leads to an increase in the rate of HDR, with a corresponding decrease in the rate of NHEJ repair. We then investigated whether a similar cold shock could lead to an increase in the rate of HDR in the mouse embryo. By analyzing the efficiency of gene editing using single nucleotide polymorphism changes and loxP insertion at three different genetic loci, we found that a transient reduction in temperature after zygote electroporation of CRISPR-Cas9 ribonucleoprotein with a single-stranded oligodeoxynucleotide repair template did indeed increase knockin efficiency, without affecting embryonic development. The efficiency of gene editing with and without the cold shock was first assessed by genotyping blastocysts. As a proof of concept, we then confirmed that the modified embryo culture conditions were compatible with live births by targeting the coat color gene tyrosinase and observing the repair of the albino mutation. Taken together, our data suggest that a transient cold shock could offer a simple and robust way to improve knockin outcomes in both stem cells and zygotes.

A Practical Classification System for Acute Cervical Spinal Cord Injury Based on a Three-Phased Modified Delphi Process From the AOSpine Spinal Cord Injury Knowledge Forum

STUDY DESIGN

A modified Delphi study.

OBJECTIVE

To assess current practice patterns in the management of cervical spinal cord injury (SCI) and develop a simplified, practical classification system which offers ease of use in the acute setting, incorporates modern diagnostic tools and provides utility in determining treatment strategies for cervical SCI.

METHODS

A three-phase modified Delphi procedure was performed between April 2020 and December 2021. During the first phase, members of the AOSpine SCI Knowledge forum proposed variables of importance for classifying and treating cervical SCI. The second phase involved an international survey of spine surgeons gauging practices surrounding the role and timing of surgery for cervical SCI and opinions regarding factors which most influence these practices. For the third phase, information obtained from phases 1 and 2 were used to draft a new classification system.

RESULTS

396 surgeons responded to the survey. Neurological status, spinal stability and cord compression were the most important variables influencing decisions surrounding the role and timing of surgery. The majority (>50%) of respondents preferred to perform surgery within 24 hours post-SCI in clinical scenarios in which there was instability, severe cord compression or severe neurology. Situations in which <50% of respondents were inclined to operate early included: SCI with mild neurological impairments, with cord compression but without instability (with or without medical comorbidities), and SCI without cord compression or instability.

CONCLUSIONS

Spinal stability, cord compression and neurological status are the most important variables influencing surgeons' practices surrounding the surgical management of cervical SCI. Based on these results, a simplified classification system for acute cervical SCI has been proposed.

Interventions to Optimize Spinal Cord Perfusion in Patients With Acute Traumatic Spinal Cord Injury: An Updated Systematic Review

STUDY DESIGN

Systematic review update.

OBJECTIVES

Interventions that aim to optimize spinal cord perfusion are thought to play an important role in minimizing secondary ischemic damage and improving outcomes in patients with acute traumatic spinal cord injuries (SCIs). However, exactly how to optimize spinal cord perfusion and enhance neurologic recovery remains controversial. We performed an update of a recent systematic review (Evaniew et al, J. Neurotrauma 2020) to evaluate the effects of Mean Arterial Pressure (MAP) support or Spinal Cord Perfusion Pressure (SCPP) support on neurological recovery and rates of adverse events among patients with acute traumatic SCI.

METHODS

We searched PubMed/MEDLINE, EMBASE and ClinicalTrials.gov for new published reports. Two reviewers independently screened articles, extracted data, and evaluated risk of bias. We implemented the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) approach to rate confidence in the quality of the evidence.

RESULTS

From 569 potentially relevant new citations since 2019, we identified 9 new studies for inclusion, which were combined with 19 studies from a prior review to give a total of 28 studies. According to low or very low quality evidence, the effect of MAP support on neurological recovery is uncertain, and increased SCPP may be associated with improved neurological recovery. Both approaches may involve risks for specific adverse events, but the importance of these adverse events to patients remains unclear. Very low quality evidence failed to yield reliable guidance about particular monitoring techniques, perfusion ranges, pharmacological agents, or durations of treatment.

CONCLUSIONS

This update provides an evidence base to support the development of a new clinical practice guideline for the hemodynamic management of patients with acute traumatic SCI. While avoidance of hypotension and maintenance of spinal cord perfusion are important principles in the management of an acute SCI, the literature does not provide high quality evidence in support of a particular protocol. Further prospective, controlled research studies with objective validated outcome assessments are required to examine interventions to optimize spinal cord perfusion in this setting.

Timing of Decompressive Surgery in Patients With Acute Spinal Cord Injury: Systematic Review Update

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

Surgical decompression is a cornerstone in the management of patients with traumatic spinal cord injury (SCI); however, the influence of the timing of surgery on neurological recovery after acute SCI remains controversial. This systematic review aims to summarize current evidence on the effectiveness, safety, and cost-effectiveness of early (≤24 hours) or late (>24 hours) surgery in patients with acute traumatic SCI for all levels of the spine. Furthermore, this systematic review aims to evaluate the evidence with respect to the impact of ultra-early surgery (earlier than 24 hours from injury) on these outcomes.

METHODS

A systematic search of the literature was performed using the MEDLINE database (PubMed), Cochrane database, and EMBASE. Two reviewers independently screened the citations from the search to determine whether an article satisfied predefined inclusion and exclusion criteria. For all key questions, we focused on primary studies with the least potential for bias and those that controlled for baseline neurological status and specified time from injury to surgery. Risk of bias of each article was assessed using standardized tools based on study design. Finally, the overall strength of evidence for the primary outcomes was assessed using the GRADE approach. Data were synthesized both qualitatively and quantitively using meta-analyses.

RESULTS

Twenty-one studies met inclusion and exclusion criteria and formed the evidence base for this review update. Seventeen studies compared outcomes between patients treated with early (≤24 hours from injury) compared to late (>24 hours) surgical decompression. An additional 4 studies evaluated even earlier time frames: <4, <5, <8 or <12 hours. Based on moderate evidence, patients were 2 times more likely to recover by ≥ 2 grades on the ASIA Impairment Score (AIS) at 6 months (RR: 2.76, 95% CI 1.60 to 4.98) and 12 months (RR: 1.95, 95% CI 1.26 to 3.18) if they were decompressed within 24 hours compared to after 24 hours. Furthermore, moderate evidence suggested that patients receiving early decompression had an additional 4.50 (95% CI 1.70 to 7.29) point improvement on the ASIA motor score. With respect to administrative outcomes, there was low evidence that early decompression may decrease acute hospital length of stay. In terms of safety, there was moderate evidence that suggested the rate of major complications does not differ between patients undergoing early compared to late surgery. Furthermore, there was no difference in rates of mortality, surgical device-related complications, sepsis/systemic infection or neurological deterioration based on timing of surgery. Firm conclusions were not possible with respect to the impact of ultra-early surgery on neurological, functional or safety outcomes given the poor-quality studies, imprecision and the overlap in the time frames examined.

CONCLUSIONS

This review provides an evidence base to support the update on clinical practice guidelines related to the timing of surgical decompression in acute SCI. Overall, the strength of evidence was moderate that early surgery (≤24 hours from injury) compared to late (>24 hours) results in clinically meaningful improvements in neurological recovery. Further studies are required to delineate the role of ultra-early surgery in patients with acute SCI.

Donor template delivery by recombinant adeno-associated virus for the production of knock-in mice

BACKGROUND

The ability of recombinant adeno-associated virus to transduce preimplantation mouse embryos has led to the use of this delivery method for the production of genetically altered knock-in mice via CRISPR-Cas9. The potential exists for this method to simplify the production and extend the types of alleles that can be generated directly in the zygote, obviating the need for manipulations of the mouse genome via the embryonic stem cell route.

RESULTS

We present the production data from a total of 13 genetically altered knock-in mouse models generated using CRISPR-Cas9 electroporation of zygotes and delivery of donor repair templates via transduction with recombinant adeno-associated virus. We explore the efficiency of gene targeting at a total of 12 independent genetic loci and explore the effects of allele complexity and introduce strategies for efficient identification of founder animals. In addition, we investigate the reliability of germline transmission of the engineered allele from founder mice generated using this methodology. By comparing our production data against genetically altered knock-in mice generated via gene targeting in embryonic stem cells and their microinjection into blastocysts, we assess the animal cost of the two methods.

CONCLUSIONS

Our results confirm that recombinant adeno-associated virus transduction of zygotes provides a robust and effective delivery route for donor templates for the production of knock-in mice, across a range of insertion sizes (0.9-4.7 kb). We find that the animal cost of this method is considerably less than generating knock-in models via embryonic stem cells and thus constitutes a considerable 3Rs reduction.

Egg hatching success is influenced by the time of thermal stress in four hard tick species

Ticks are blood-feeding arthropods responsible for the transmission of disease-causing pathogens to a wide range of vertebrate hosts, including livestock and humans. Tick-borne diseases have been implicated in significant economic losses to livestock production, and this threat will increase as these obligate parasites widen their geographical ranges. Similar to other ectotherms, thermal stress due to changing global temperatures has been shown to influence tick survival and distribution. However, studies on the influence of extreme temperatures in ticks have focused on advanced, mobile stages, ignoring immobile stages that cannot move to more favorable microhabitats. In this study, low- and high-temperature regimens were assessed in relation to egg viability for hard tick species-Amblyomma maculatum (Gulf Coast tick), Ixodes scapularis (black-legged tick), Dermacentor variabilis (American dog tick), and Rhipicephalus sanguineus (Brown dog tick). Tick eggs exposed early in development (freshly laid during early embryo development) were significantly more susceptible to thermal stress when compared with those exposed later in development (late embryo development denoted by a fecal spot). Based on our studies, differences in egg hatching success among treatments were greater than in hatching success when comparing species. Lastly, there was evidence of extreme thermal exposure significantly altering the hatching times of tick eggs for specific treatments. These results provide insights into the critical period for tick egg viability in relation to thermal exposure and tick survival associated with stress and climate change.

Shieldin and CST co-orchestrate DNA polymerase-dependent tailed-end joining reactions independently of 53BP1-governed repair pathway choice

53BP1 regulates DNA end-joining in lymphocytes, diversifying immune antigen receptors. This involves nucleosome-bound 53BP1 at DNA double-stranded breaks (DSBs) recruiting RIF1 and shieldin, a poorly understood DNA-binding complex. The 53BP1-RIF1-shieldin axis is pathological in BRCA1-mutated cancers, blocking homologous recombination (HR) and driving illegitimate non-homologous end-joining (NHEJ). However, how this axis regulates DNA end-joining and HR suppression remains unresolved. We investigated shieldin and its interplay with CST, a complex recently implicated in 53BP1-dependent activities. Immunophenotypically, mice lacking shieldin or CST are equivalent, with class-switch recombination co-reliant on both complexes. ATM-dependent DNA damage signalling underpins this cooperation, inducing physical interactions between these complexes that reveal shieldin as a DSB-responsive CST adaptor. Furthermore, DNA polymerase ζ functions downstream of shieldin, establishing DNA fill-in synthesis as the physiological function of shieldin-CST. Lastly, 53BP1 suppresses HR and promotes NHEJ in BRCA1-deficient mice and cells independently of shieldin. These findings showcase the resilience of the 53BP1 pathway, achieved through the collaboration of chromatin-bound 53BP1 complexes and DNA end-processing effector proteins.

Characterization of meiotic recombination intermediates through gene knockouts in founder hybrid mice

Mammalian meiotic recombination proceeds via repair of hundreds of programmed DNA double-strand breaks, which requires choreographed binding of RPA, DMC1, and RAD51 to single-stranded DNA substrates. High-resolution in vivo binding maps of these proteins provide insights into the underlying molecular mechanisms. When assayed in F1-hybrid mice, these maps can distinguish the broken chromosome from the chromosome used as template for repair, revealing more mechanistic detail and enabling the structure of the recombination intermediates to be inferred. By applying CRISPR-Cas9 mutagenesis directly on F1-hybrid embryos, we have extended this approach to explore the molecular detail of recombination when a key component is knocked out. As a proof of concept, we have generated hybrid biallelic knockouts of Dmc1 and built maps of meiotic binding of RAD51 and RPA in them. DMC1 is essential for meiotic recombination, and comparison of these maps with those from wild-type mice is informative about the structure and timing of critical recombination intermediates. We observe redistribution of RAD51 binding and complete abrogation of D-loop recombination intermediates at a molecular level in Dmc1 mutants. These data provide insight on the configuration of RPA in D-loop intermediates and suggest that stable strand exchange proceeds via multiple rounds of strand invasion with template switching in mouse. Our methodology provides a high-throughput approach for characterization of gene function in meiotic recombination at low animal cost.

The Frequency of Symptoms in Patients With a Diagnosis of Degenerative Cervical Myelopathy: Results of a Scoping Review

STUDY DESIGN

Delayed diagnosis of degenerative cervical myelopathy (DCM) is associated with reduced quality of life and greater disability. Developing diagnostic criteria for DCM has been identified as a top research priority.

OBJECTIVES

This scoping review aims to address the following questions: What is the diagnostic accuracy and frequency of clinical symptoms in patients with DCM?

METHODS

A scoping review was conducted using a database of all primary DCM studies published between 2005 and 2020. Studies were included if they (i) assessed the diagnostic accuracy of a symptom using an appropriate control group or (ii) reported the frequency of a symptom in a cohort of DCM patients.

RESULTS

This review identified three studies that discussed the diagnostic accuracy of various symptoms and included a control group. An additional 58 reported on the frequency of symptoms in a cohort of patients with DCM. The most frequent and sensitive symptoms in DCM include unspecified paresthesias (86%), hand numbness (82%) and hand paresthesias (79%). Neck and/or shoulder pain was present in 51% of patients with DCM, whereas a minority had back (19%) or lower extremity pain (10%). Bladder dysfunction was uncommon (38%) although more frequent than bowel (23%) and sexual impairment (4%). Gait impairment is also commonly seen in patients with DCM (72%).

CONCLUSION

Patients with DCM present with many different symptoms, most commonly sensorimotor impairment of the upper extremities, pain, bladder dysfunction and gait disturbance. If patients present with a combination of these symptoms, further neuroimaging is indicated to confirm the diagnosis of DCM.

The value of Clinical signs in the diagnosis of Degenerative Cervical Myelopathy - A Systematic review and Meta-analysis

STUDY DESIGN

Delayed diagnosis of degenerative cervical myelopathy (DCM) is likely due to a combination of its subtle symptoms, incomplete neurological assessments by clinicians and a lack of public and professional awareness. Diagnostic criteria for DCM will likely facilitate earlier referral for definitive management.

OBJECTIVES

This systematic review aims to determine (i) the diagnostic accuracy of various clinical signs and (ii) the association between clinical signs and disease severity in DCM?

METHODS

A search was performed to identify studies on adult patients that evaluated the diagnostic accuracy of a clinical sign used for diagnosing DCM. Studies were also included if they assessed the association between the presence of a clinical sign and disease severity. The QUADAS-2 tool was used to evaluate the risk of bias of individual studies.

RESULTS

This review identified eleven studies that used a control group to evaluate the diagnostic accuracy of various signs. An additional 61 articles reported on the frequency of clinical signs in a cohort of DCM patients. The most sensitive clinical tests for diagnosing DCM were the Tromner and hyperreflexia, whereas the most specific tests were the Babinski, Tromner, clonus and inverted supinator sign. Five studies evaluated the association between the presence of various clinical signs and disease severity. There was no definite association between Hoffmann sign, Babinski sign or hyperreflexia and disease severity.

CONCLUSION

The presence of clinical signs suggesting spinal cord compression should encourage health care professionals to pursue further investigation, such as neuroimaging to either confirm or refute a diagnosis of DCM.

Graded Quasiperiodic Metamaterials Perform Fractal Rainbow Trapping

The rainbow trapping phenomenon of graded metamaterials can be combined with the fractal spectra of quasiperiodic waveguides to give a metamaterial that performs fractal rainbow trapping. This is achieved through a graded cut-and-project algorithm that yields a geometry for which the effective projection angle is graded along its length. As a result, the fractal structure of local band gaps varies with position, leading to broadband "fractal" rainbow trapping. We demonstrate this principle by designing an acoustic waveguide, which is characterised using theory, simulation and experiments.

A missense mutation in Ehd1 associated with defective spermatogenesis and male infertility

Normal function of the C-terminal Eps15 homology domain-containing protein 1 (EHD1) has previously been associated with endocytic vesicle trafficking, shaping of intracellular membranes, and ciliogenesis. We recently identified an autosomal recessive missense mutation c.1192C>T (p.R398W) of EHD1 in patients who had low molecular weight proteinuria (0.7-2.1 g/d) and high-frequency hearing loss. It was already known from Ehd1 knockout mice that inactivation of Ehd1 can lead to male infertility. However, the exact role of the EHD1 protein and its p.R398W mutant during spermatogenesis remained still unclear. Here, we report the testicular phenotype of a knockin mouse model carrying the p.R398W mutation in the EHD1 protein. Male homozygous knockin mice were infertile, whereas the mutation had no effect on female fertility. Testes and epididymes were significantly reduced in size and weight. The testicular epithelium appeared profoundly damaged and had a disorganized architecture. The composition of developing cell types was altered. Malformed acrosomes covered underdeveloped and misshaped sperm heads. In the sperm tail, midpieces were largely missing indicating disturbed assembly of the sperm tail. Defective structures, i.e., nuclei, acrosomes, and sperm tail midpieces, were observed in large vacuoles scattered throughout the epithelium. Interestingly, cilia formation itself did not appear to be affected, as the axoneme and other parts of the sperm tails except the midpieces appeared to be intact. In wildtype mice, EHD1 co-localized with acrosomal granules on round spermatids, suggesting a role of the EHD1 protein during acrosomal development. Wildtype EHD1 also co-localized with the VPS35 component of the retromer complex, whereas the p.R398W mutant did not. The testicular pathologies appeared very early during the first spermatogenic wave in young mice (starting at 14 dpp) and tubular destruction worsened with age. Taken together, EHD1 plays an important and probably multifaceted role in spermatogenesis in mice. Therefore, EHD1 may also be a hitherto underestimated infertility gene in humans.

Glucose Controls Glucagon Secretion by Regulating Fatty Acid Oxidation in Pancreatic α-Cells

Whole-body glucose homeostasis is coordinated through secretion of glucagon and insulin from pancreatic islets. When glucose is low, glucagon is released from α-cells to stimulate hepatic glucose production. However, the mechanisms that regulate glucagon secretion from pancreatic α-cells remain unclear. Here we show that in α-cells, the interaction between fatty acid oxidation and glucose metabolism controls glucagon secretion. The glucose-dependent inhibition of glucagon secretion relies on pyruvate dehydrogenase and carnitine palmitoyl transferase 1a activity and lowering of mitochondrial fatty acid oxidation by increases in glucose. This results in reduced intracellular ATP and leads to membrane repolarization and inhibition of glucagon secretion. These findings provide a new framework for the metabolic regulation of the α-cell, where regulation of fatty acid oxidation by glucose accounts for the stimulation and inhibition of glucagon secretion.

ARTICLE HIGHLIGHTS

It has become clear that dysregulation of glucagon secretion and α-cell function plays an important role in the development of diabetes, but we do not know how glucagon secretion is regulated. Here we asked whether glucose inhibits fatty acid oxidation in α-cells to regulate glucagon secretion. We found that fatty acid oxidation is required for the inhibitory effects of glucose on glucagon secretion through reductions in ATP. These findings provide a new framework for the regulation of glucagon secretion by glucose.

Assessing the accuracy of the International Classification of Disease (ICD) framework in the identification of patients with chronic subdural haematoma from hospital records

BACKGROUND

Chronic subdural hematoma (CSDH) is one of the commonest neurosurgical pathologies with an increasing incidence. Observational studies of routine care have demonstrated high perioperative morbidity and approximately 10% mortality at one year. The development, implementation, and evaluation of a potential care framework relies on an accurate and reproducible method of case identification and case ascertainment. With this manuscript, we report on the accuracy of diagnostic ICD codes for identifying patients with CSDH from retrospective electronic data and explore whether basic demographic data could improve the identification of CSDH.

METHODS

Data were collected retrospectively from the hospital administrative system between 2014 and 2018 of all patients coded with either S065 or I620. Analysis of the ICD codes in identifying patients with CSDH diagnosis was calculated using the caretR package in RStudioR,.and stepwise logistic regression analysis was performed to evaluate the best predictive model for CSDH.

RESULTS

A total of 1861 patients were identified. Of these, 189 (10.2%) had a diagnosis of non-traumatic SDH (I620) and 1672 (89.8%) traumatic subdural haematomas (S065). Variables that identified CSDH as a diagnosis on univariate logistic regression included male sex (Odds Ratios (OR) - 1.606 (1.197-2.161), elderly age (OR) - 1.023 (1.015-1.032) per year for age (p < 0.001) and shorter length of hospital stay. Using stepwise regression against AIC the best model to predict CSDH included male sex, older age, and shorter LOS. The calculated sensitivity for identifying CSDH with the model is 88.4% with a specificity of 84.5% and PPV of 87.9%.

CONCLUSION

CSDH is a common neurosurgical pathology with increasing incidence and ongoing unmet clinical need. We demonstrate that case ascertainment for research purposes can be improved with the incorporation of additional demographic data but at the expense of significant case exclusion.

Factors Influencing Surgical Decision-Making in the Posterior Laminectomy With Fixation for Degenerative Cervical Myelopathy (POLYFIX-DCM) Trial: Survey Study

BACKGROUND

Degenerative cervical myelopathy (DCM) is estimated to affect 2% of the adult population. DCM occurs when degenerative processes cause compression and injure the spinal cord. Surgery to remove the stress caused by the compression of the spinal cord is the mainstay of treatment, with a range of techniques in use. Although various factors are described to inform the selection of these techniques, there needs to be more consensus and limited comparative evidence.

OBJECTIVE

The main objective of this survey was to explore the variation of practice and decision-making, with a focus on laminectomy versus laminectomy and fusion in posterior surgery of the cervical spine. We present the results of a survey conducted among the principal investigators (PIs) of the National Institute for Health and Care Research (NIHR) randomized controlled trial on posterior laminectomy with fixation for degenerative cervical myelopathy (POLYFIX-DCM).

METHODS

A series of 7 cases were shared with 24 PIs using SurveyMonkey. Each case consisted of a midsagittal T2-weighted magnetic resonance imaging and lateral cervical x-rays in flexion and extension. Surgeons were asked if their preferred approach was anterior or posterior. If posterior, they were asked whether they preferred to instrument and whether they had the equipoise to randomize in the NIHR POLYFIX-DCM trial. Variability in decision-making was then explored using factors reported to inform decision-making, such as alignment, location of compression, number of levels operated, presence of mobile spondylolisthesis, and patient age.

RESULTS

The majority of PIs (16/30, 53%) completed the survey. Overall, PIs favored a posterior approach (12/16, 75%) with instrumentation (75/112, average 66%) and would randomize (67/112, average 62%) most cases. Factors reported to inform decision-making poorly explained variability in responses in both univariate testing and with a multivariate model (R2=0.1). Only surgeon experience of more than 5 years and orthopedic specialty training background were significant predictors, both associated with an anterior approach (odds ratio [OR] 1.255; P=.02 and OR 1.344; P=.007, respectively) and fusion for posterior procedures (OR 0.628; P<.001 and OR 1.344; P<.001, respectively). Surgeon experience also significantly affected the openness to randomize, with those with more than 5 years of experience less likely to randomize (OR -0.68; P<.001).

CONCLUSIONS

In this representative sample of spine surgeons participating in the POLYFIX-DCM trial as investigators, there is no consensus on surgical strategy, including the role of instrumented fusion following posterior decompression. Overall, this study supports the view that there appears to be a clinical equipoise, and conceptually, a randomized controlled trial appears feasible, which sets the scene for the NIHR POLYFIX-DCM trial.

Rapidly Deteriorating Degenerative Cervical Myelopathy Following Ventricular Shunt Revision for Hydrocephalus: Case Report

A female patient in her early 40s presented with a several-month history of gait unsteadiness and dragging her left leg. She had a background of congenital hydrocephalus, treated with a ventriculoatrial shunt. On examination, she had increased tone and brisk reflexes in the lower limbs and a positive Hoffmann sign. A computed tomography (CT) scan and shunt series x-rays identified hydrocephalus secondary to a disconnected shunt. Magnetic resonance imaging (MRI) of her cervical spine was also performed as part of the workup for her presenting symptoms and demonstrated features compatible with degenerative cervical myelopathy (DCM). The patient subsequently underwent a shunt revision. Following the operation, her walking and hand function deteriorated over a period of several weeks. She consequently underwent an anterior cervical decompression and fusion for DCM, which partially improved her symptoms. The sequence of events suggests that the shunt surgery may have precipitated a worsening of the DCM. Possible explanations include spinal cord injury related to neck extension or hypoperfusion during intubation and general anesthesia or the loss of cerebrospinal fluid cushioning following the reinstitution of effective cerebrospinal fluid shunting. Surgeons should be alert to this possibility and offer prompt surgical intervention for DCM if required.

An Overview of Pancreatic Neuroendocrine Tumors and an Update on Endoscopic Techniques for Their Management

The growing importance of advanced endoscopy in the diagnosis and treatment of pancreatic neuroendocrine neoplasms (PanNETs) necessitates a comprehensive understanding of various biochemical markers, genetic testing methods, radiological techniques, and treatment approaches that encompass multiple disciplines within and beyond gastrointestinal oncology. This review aims to highlight key aspects of these topics, with a specific focus on emerging EUS-guided procedures for the management of PanNETs.

Secondary analysis of a James Lind Alliance priority setting partnership to facilitate knowledge translation in degenerative cervical myelopathy (DCM): insights from AO Spine RECODE-DCM

OBJECTIVES

To explore whether a James Lind Alliance Priority Setting Partnership could provide insights on knowledge translation within the field of degenerative cervical myelopathy (DCM).

DESIGN

Secondary analysis of a James Lind Alliance Priority Setting Partnership process for DCM.

PARTICIPANTS AND SETTING

DCM stake holders, including spinal surgeons, people with myelopathy and other healthcare professionals, were surveyed internationally. Research suggestions submitted by stakeholders but considered answered were identified. Sampling characteristics of respondents were compared with the overall cohort to identify subgroups underserved by current knowledge translation.

RESULTS

The survey was completed by 423 individuals from 68 different countries. A total of 22% of participants submitted research suggestions that were considered 'answered'. There was a significant difference between responses from different stakeholder groups (p<0.005). Spinal surgeons were the group which was most likely to submit an 'answered' research question. Respondents from South America were also most likely to submit 'answered' questions, when compared with other regions. However, there was no significant difference between responses from different stakeholder regions (p=0.4).

CONCLUSIONS

Knowledge translation challenges exist within DCM. This practical approach to measuring knowledge translation may offer a more responsive assessment to guide interventions, complementing existing metrics.

Investigating blood alcohol concentrations in injury- related deaths before and during the COVID-19 national lockdown in Western Cape Province, South Africa: A cross-sectional retrospective review

BACKGROUND

Alcohol is a significant contributor to injury-related morbidity and mortality in South Africa (SA). During the COVID-19global pandemic, restrictions to movement and to legal access to alcohol (i.e. ethanol) were introduced in SA.

OBJECTIVES

To investigate the effect of alcohol bans during the COVID-19 lockdown periods on injury-related mortality and blood alcoholconcentrations (BACs) in these deaths.

METHODS

A retrospective, cross-sectional analysis of injury-related deaths in Western Cape Province (WC), SA, between 1 January 2019 and31 December 2020 was conducted. Cases where BAC testing was performed were further examined according to the periods of lockdownand alcohol restrictions.

RESULTS

A total of 16 027 injury-related cases were admitted to Forensic Pathology Service mortuaries in the WC over the 2-year period. Anaverage decrease of 15.7% injury-related deaths in 2020 compared with 2019 was noted, as well as a 47.7% decrease in injury-related deathsduring hard lockdown (April - May 2020) compared with the same period in 2019. In the injury-related deaths, 12 077 (75.4%) had bloodspecimens collected for BAC testing. In 5 078 (42.0%) of submitted cases, a positive BAC (≥0.01 g/100 mL) was reported. No significantdifference was observed in the mean positive BAC between 2019 and 2020. However, in April and May 2020, the mean BAC observed(0.13 g/100 mL) was less than that in 2019 (0.18 g/100 mL). A high number of positive BACs in the 12- 17-year age group (23.4%) was observed.

CONCLUSION

There was a clear decrease in injury-related deaths in the WC during the COVID-19-related lockdown periods, whichcoincided with the alcohol ban and restriction of movement, and an increase following relaxation of restrictions on alcohol sales andmovement. The data illustrate that mean BACs were similar between all periods of alcohol restriction compared with 2019, apart from hardlockdown in April - May 2020. This coincided with a smaller mortuary intake during the level 5 and 4 lockdown periods.

Investigating blood alcohol concentrations in injury-related deaths before and during the COVID-19 National lockdown in Western Cape, South Africa: A cross-sectional retrospective review

BACKGROUND

Alcohol is a significant contributor to injury-related morbidity and mortality in South Africa (SA).  During the COVID-19 global pandemic, restrictions to movement and to the legal access of alcohol* were introduced in SA.  This study aimed to investigate the effect of alcohol bans during the COVID-19 lockdown periods on injury-related mortality and the blood alcohol concentrations (BAC) in these deaths.

METHODS

A retrospective, cross-sectional analysis of injury-related deaths in Western Cape (WC) province, SA, between 1 January 2019 to 31 December 2020 was conducted. Cases where BAC testing was performed were further examined according to the periods of lockdown (AL5-1) and alcohol restrictions.

RESULTS

A total of 16,027 injury-related cases were admitted to Forensic Pathology Service mortuaries in the WC over the two-year period.  An average decrease of 15.7% injury-related deaths in 2020 compared to 2019 was noted, as well as a 47.7% decrease in injury-related deaths during hard lockdown (April -May 2020) compared to the same period in 2019. In the injury-related deaths, 12,077 (75.4%) had blood specimens collected for BAC testing. In 5,078 (42.0%) of submitted cases, a positive BAC (≥0.01g/100 mL) was reported. No significant difference was observed in the mean positive BAC between 2019 and 2020, however in April and May 2020, the mean BACs observed (0.13 g/100 mL) was less than that in 2019 (0.18 g/100 mL). A high number of positive BACs in the 12-17-year age group (±23.4%) was observed.

CONCLUSION

There was a clear decrease in injury-related deaths in the WC during the COVID-19-related lockdown periods that coincided with the alcohol ban and restriction of movement and an increase following relaxation of restrictions on alcohol sales and movement. The data illustrated that mean BACs were similar between all periods of alcohol restriction compared to 2019, apart from hard lockdown in April-May, 2020.  This coincided with a smaller mortuary intake during the level 5 and 4 lockdown periods.   Keywords: Alcohol; blood alcohol concentration; COVID-19; injury; lockdown; South Africa; violent death; Western Cape   * Alcohol refers to ethanol.

Increasing incidence of spondylodiscitis in England: An analysis of the national health service (NHS) hospital episode statistics from 2012 to 2021

Background

Spondylodiscitis is a potentially life-threatening infection of the intervertebral disk and adjacent vertebral bodies, with a mortality rate of 2-20%. Given the aging population, the increase in immunosuppression, and intravenous drug use in England, the incidence of spondylodiscitis is postulated to be increasing; however, the exact epidemiological trend in England remains unknown.

Objective

The Hospital Episode Statistics (HES) database contains details of all secondary care admissions across NHS hospitals in England. This study aimed to use HES data to characterise the annual activity and longitudinal change of spondylodiscitis in England.

Methods

The HES database was interrogated for all cases of spondylodiscitis between 2012 and 2019. Data for the length of stay, waiting time, age-stratified admissions, and 'Finished Consultant Episodes' (FCEs), which correspond to a patient's hospital care under a lead clinician, were analysed.

Results

In total, 43135 FCEs for spondylodiscitis were identified between 2012 and 2022, of which 97.1% were adults. Overall admissions for spondylodiscitis have risen from 3 per 100,000 population in 2012/13 to 4.4 per 100,000 population in 2020/21. Similarly, FCEs have increased from 5.8 to 10.3 per 100,000 population, in 2012-2013 and 2020/21 respectively. The highest increase in admissions from 2012 to 2021 was recorded for those aged 70-74 (117% increase) and aged 75-59 (133% increase), among those of working age for those aged 60-64 years (91% increase).

Conclusion

Population-adjusted admissions for spondylodiscitis in England have risen by 44% between 2012 and 2021. Healthcare policymakers and providers must acknowledge the increasing burden of spondylodiscitis and make spondylodiscitis a research priority.

Antimicrobial use in animals: a journey towards integrated surveillance

In 2015, the World Organisation for Animal Health (WOAH, founded as OIE) initiated the annual collection of data on antimicrobials intended for use in animals using a Microsoft Excel questionnaire. In 2022, WOAH initiated the migration to a customised interactive online system: ANIMUSE Global Database. This system enables national Veterinary Services not only to monitor and report data more easily and more accurately, but also to visualise, analyse and use data for surveillance purposes to their own benefit in the implementation of national action plans on antimicrobial resistance. This journey started seven years ago, with progressive improvements in the way data are collected, analysed and reported and continuous adaptations to overcome various challenges encountered (e.g. data confidentiality, training of civil servants, calculation of active ingredients, standardisation to enable fair comparisons and trend analyses, and data interoperability). Technical developments have been key in the success of this endeavour. However, it is important not to underestimate the importance of the human element: to listen to WOAH Members and their needs, and to exchange to solve issues, adapt tools, and gain and maintain trust. The journey is not over yet, and more developments are foreseen, such as to complement current data sources with data collected directly at the farm level; strengthen interoperability and integrated analysis with cross-sectoral databases; and facilitate institutionalisation of data collection and systematic use in monitoring, evaluation, lesson learning, reporting and, eventually, surveillance of antimicrobial use and antimicrobial resistance when implementing and updating national action plans. This paper describes how all these challenges were overcome and how future challenges will be addressed.

Loss of RREB1 in pancreatic beta cells reduces cellular insulin content and affects endocrine cell gene expression

AIMS/HYPOTHESIS

Genome-wide studies have uncovered multiple independent signals at the RREB1 locus associated with altered type 2 diabetes risk and related glycaemic traits. However, little is known about the function of the zinc finger transcription factor Ras-responsive element binding protein 1 (RREB1) in glucose homeostasis or how changes in its expression and/or function influence diabetes risk.

METHODS

A zebrafish model lacking rreb1a and rreb1b was used to study the effect of RREB1 loss in vivo. Using transcriptomic and cellular phenotyping of a human beta cell model (EndoC-βH1) and human induced pluripotent stem cell (hiPSC)-derived beta-like cells, we investigated how loss of RREB1 expression and activity affects pancreatic endocrine cell development and function. Ex vivo measurements of human islet function were performed in donor islets from carriers of RREB1 type 2 diabetes risk alleles.

RESULTS

CRISPR/Cas9-mediated loss of rreb1a and rreb1b function in zebrafish supports an in vivo role for the transcription factor in beta cell mass, beta cell insulin expression and glucose levels. Loss of RREB1 also reduced insulin gene expression and cellular insulin content in EndoC-βH1 cells and impaired insulin secretion under prolonged stimulation. Transcriptomic analysis of RREB1 knockdown and knockout EndoC-βH1 cells supports RREB1 as a novel regulator of genes involved in insulin secretion. In vitro differentiation of RREB1KO/KO hiPSCs revealed dysregulation of pro-endocrine cell genes, including RFX family members, suggesting that RREB1 also regulates genes involved in endocrine cell development. Human donor islets from carriers of type 2 diabetes risk alleles in RREB1 have altered glucose-stimulated insulin secretion ex vivo, consistent with a role for RREB1 in regulating islet cell function.

CONCLUSIONS/INTERPRETATION

Together, our results indicate that RREB1 regulates beta cell function by transcriptionally regulating the expression of genes involved in beta cell development and function.

Targeting patient recovery priorities in degenerative cervical myelopathy: design and rationale for the RECEDE-Myelopathy trial-study protocol

INTRODUCTION

Degenerative cervical myelopathy (DCM) is a common and disabling condition of symptomatic cervical spinal cord compression secondary to degenerative changes in spinal structures leading to a mechanical stress injury of the spinal cord. RECEDE-Myelopathy aims to test the disease-modulating activity of the phosphodiesterase 3/phosphodiesterase 4 inhibitor Ibudilast as an adjuvant to surgical decompression in DCM.

METHODS AND ANALYSIS

RECEDE-Myelopathy is a multicentre, double-blind, randomised, placebo-controlled trial. Participants will be randomised to receive either 60-100 mg Ibudilast or placebo starting within 10 weeks prior to surgery and continuing for 24 weeks after surgery for a maximum of 34 weeks. Adults with DCM, who have a modified Japanese Orthopaedic Association (mJOA) score 8-14 inclusive and are scheduled for their first decompressive surgery are eligible for inclusion. The coprimary endpoints are pain measured on a visual analogue scale and physical function measured by the mJOA score at 6 months after surgery. Clinical assessments will be undertaken preoperatively, postoperatively and 3, 6 and 12 months after surgery. We hypothesise that adjuvant therapy with Ibudilast leads to a meaningful and additional improvement in either pain or function, as compared with standard routine care.

STUDY DESIGN

Clinical trial protocol V.2.2 October 2020.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from HRA-Wales.The results will be presented at an international and national scientific conferences and in a peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ISRCTN Number: ISRCTN16682024.

Insights into the Role of a Cardiomyopathy-Causing Genetic Variant in ACTN2

Pathogenic variants in ACTN2, coding for alpha-actinin 2, are known to be rare causes of Hypertrophic Cardiomyopathy. However, little is known about the underlying disease mechanisms. Adult heterozygous mice carrying the Actn2 p.Met228Thr variant were phenotyped by echocardiography. For homozygous mice, viable E15.5 embryonic hearts were analysed by High Resolution Episcopic Microscopy and wholemount staining, complemented by unbiased proteomics, qPCR and Western blotting. Heterozygous Actn2 p.Met228Thr mice have no overt phenotype. Only mature males show molecular parameters indicative of cardiomyopathy. By contrast, the variant is embryonically lethal in the homozygous setting and E15.5 hearts show multiple morphological abnormalities. Molecular analyses, including unbiased proteomics, identified quantitative abnormalities in sarcomeric parameters, cell-cycle defects and mitochondrial dysfunction. The mutant alpha-actinin protein is found to be destabilised, associated with increased activity of the ubiquitin-proteasomal system. This missense variant in alpha-actinin renders the protein less stable. In response, the ubiquitin-proteasomal system is activated; a mechanism that has been implicated in cardiomyopathies previously. In parallel, a lack of functional alpha-actinin is thought to cause energetic defects through mitochondrial dysfunction. This seems, together with cell-cycle defects, the likely cause of the death of the embryos. The defects also have wide-ranging morphological consequences.

A Review on Endoscopic Ultrasound-Guided Radiofrequency Ablation (EUS-RFA) of Pancreatic Lesions

The morbidity associated with pancreatectomies limits surgical options for high-risk patients with pancreatic neoplasms that warrant resection. Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) offers a minimally invasive and potentially definitive means to treat pancreatic neuroendocrine tumors and precancerous pancreatic cystic lesions. In addition, EUS-RFA may play a role in the treatment and palliation of non-surgical cases of pancreatic adenocarcinoma. The efficacy of RFA appears to be further enhanced by systemic immunomodulatory effects. Here, we review current studies on the developing role of EUS-RFA in these pancreatic pathologies.

Children with hearing loss can use subject-verb agreement to predict during spoken language processing

Rapid processing of spoken language is aided by the ability to predict upcoming words using both semantic and syntactic cues. However, although children with hearing loss (HL) can predict upcoming words using semantic associations, little is known about their ability to predict using syntactic dependencies such as subject-verb (SV) agreement. This study examined whether school-aged children with hearing aids and/or cochlear implants can use SV agreement to predict upcoming nouns when processing spoken language. Although they did demonstrate prediction with plural SV agreement, they did so more slowly than their normal hearing (NH) peers. This may be due to weaker grammatical representations given that function words and grammatical inflections typically have lower perceptual salience. Thus, a better understanding of morphosyntactic representations in children with HL, and their ability to use these for prediction, sheds much-needed light on the online language processing challenges and abilities of this population.

Targeted Integration of Transgenes at the Mouse Gt(ROSA)26Sor Locus

The targeting of transgenic constructs at single copy into neutral genomic loci avoids the unpredictable outcomes associated with conventional random integration approaches. The Gt(ROSA)26Sor locus on chromosome 6 has been used many times for the integration of transgenic constructs and is known to be permissive for transgene expression and disruption of the gene is not associated with a known phenotype. Furthermore, the transcript made from the Gt(ROSA)26Sor locus is ubiquitously expressed and subsequently the locus can be used to drive the ubiquitous expression of transgenes.Here we report a protocol for the generation of targeted transgenic alleles at Gt(ROSA)26Sor, taking as an example a conditional overexpression allele, by PhiC31 integrase/recombinase-mediated cassette exchange of an engineered Gt(ROSA)26Sor locus in mouse embryonic stem cells. The overexpression allele is initially silenced by the presence of a loxP flanked stop sequence but can be strongly activated through the action of Cre recombinase.

Presentation, management, and outcomes of cauda equina syndrome up to one year after surgery, using clinician and participant reporting: A multi-centre prospective cohort study

Background

Cauda equina syndrome (CES) results from nerve root compression in the lumbosacral spine, usually due to a prolapsed intervertebral disc. Evidence for management of CES is limited by its infrequent occurrence and lack of standardised clinical definitions and outcome measures.

Methods

This is a prospective multi-centre observational cohort study of adults with CES in the UK. We assessed presentation, investigation, management, and all Core Outcome Set domains up to one year post-operatively using clinician and participant reporting. Univariable and multivariable associations with the Oswestry Disability Index (ODI) and urinary outcomes were investigated.

Findings

In 621 participants with CES, catheterisation for urinary retention was required pre-operatively in 31% (191/615). At discharge, only 13% (78/616) required a catheter. Median time to surgery from symptom onset was 3 days (IQR:1–8) with 32% (175/545) undergoing surgery within 48 h. Earlier surgery was associated with catheterisation (OR:2.2, 95%CI:1.5–3.3) but not with admission ODI or radiological compression. In multivariable analyses catheter requirement at discharge was associated with pre-operative catheterisation (OR:10.6, 95%CI:5.8–20.4) and one-year ODI was associated with presentation ODI (r = 0.3, 95%CI:0.2–0.4), but neither outcome was associated with time to surgery or radiological compression. Additional healthcare services were required by 65% (320/490) during one year follow up.

Interpretation

Post-operative functional improvement occurred even in those presenting with urinary retention. There was no association between outcomes and time to surgery in this observational study. Significant healthcare needs remained post-operatively.

Funding

DCN Endowment Fund funded study administration. Castor EDC provided database use. No other study funding was received.

The Role of Alcohol and Drug Intoxication in Fire-Related Incidents in Africa: A Systematic Review

Fire-related burns contribute significantly to the global burden of burn injury and mortality. Alcohol and/or drug intoxication poses a risk to burn and fire-related injury, whether intentional or unintentional, but such evidence is scarce in the African context. This review aimed to fill the knowledge gap on health determinants of fire-related morbidity and mortality regionally by investigating the role of alcohol and drug intoxication in such events. Using key concepts, an extensive search was performed on 25 databases for relevant publications. Eligible articles were critically appraised using the appraisal tool for cross-sectional studies (AXIS tool), adapted to the review's objectives and outcomes. A total of 42 articles were included, of which less than half were solely investigating burn/fire-related events. Others indirectly mentioned burn injuries as part of larger health burdens such as injury, trauma, violence and other diseases. The measurement of alcohol and/or drug intoxication was inconsistent between studies with varying results. Alcohol and drug impairment in burn incidents in Africa requires evidence-based epidemiological research, and this review illustrated the limited scope of this topic in current literature. Routine toxicological results from post-mortem examinations were identified as important data sources and several research recommendations were provided.

NDRG1 is induced by antigen-receptor signaling but dispensable for B and T cell self-tolerance

Peripheral tolerance prevents the initiation of damaging immune responses by autoreactive lymphocytes. While tolerogenic mechanisms are tightly regulated by antigen-dependent and independent signals, downstream pathways are incompletely understood. N-myc downstream-regulated gene 1 (NDRG1), an anti-cancer therapeutic target, has previously been implicated as a CD4⁺ T cell clonal anergy factor. By RNA-sequencing, we identified Ndrg1 as the third most upregulated gene in anergic, compared to naïve follicular, B cells. Ndrg1 is upregulated by B cell receptor activation (signal one) and suppressed by co-stimulation (signal two), suggesting that NDRG1 may be important in B cell tolerance. However, though Ndrg1^-/- mice have a neurological defect mimicking NDRG1-associated Charcot-Marie-Tooth (CMT4d) disease, primary and secondary immune responses were normal. We find that B cell tolerance is maintained, and NDRG1 does not play a role in downstream responses during re-stimulation of in vivo antigen-experienced CD4⁺ T cells, demonstrating that NDGR1 is functionally redundant for lymphocyte anergy.

New Mental Health Diagnosis as a Prognostic Factor for Muscle-Invasive Bladder Cancer

BACKGROUND

To examine differences in survival outcomes for muscle-invasive bladder cancer patients stratified by new mental health diagnosis.

METHODS

Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare data, we identified patients diagnosed with muscle-invasive bladder cancer between 2008 and 2014. Our primary outcome was cancer-specific and overall hazards of mortality. As a secondary outcome, we reported predictors of developing a new mental health diagnosis after bladder cancer diagnosis. We used Cox proportional hazards models to determine the impact of palliative care and mental health diagnoses on survival outcomes after adjusting for grade, stage, comorbidity index, and baseline demographics.

RESULTS

Of the 3794 patients who met inclusion criteria, 1193 (31%) were diagnosed with a mental health illness after their bladder cancer diagnosis during the 6 years in the study period. The most common diagnoses were depression (13%), alcohol and drug abuse (12%), and anxiety (11%). Patients with a post-bladder cancer mental health diagnosis had a 57% higher hazard of overall mortality (HR 1.57, P = .048) and an 80% higher hazard of bladder cancer-specific mortality (HR 1.81, P = .037) CONCLUSIONS: New mental health diagnoses are associated with worse survival in patients with muscle invasive bladder cancer. This suggests that a multimodal approach to bladder cancer treatment should include addressing the non-oncologic needs of the patient to optimize survival outcomes.

Challenges and opportunities in the care of chronic subdural haematoma: perspectives from a multi-disciplinary working group on the need for change

INTRODUCTION

A chronic subdural haematoma (cSDH) is a collection of altered blood products between the dura and brain resulting in a slowly evolving neurological deficit. It is increasingly common and, in high income countries, affects an older, multimorbid population. With changing demographics improving the care of this cohort is of increasing importance.

METHODS

We convened a cross-disciplinary working group (the 'Improving Care in Elderly Neurosurgery Initiative') in October 2020. This comprised experts in neurosurgical care and a range of perioperative stakeholders. An Implementation Science framework was used to structure discussions around the challenges of cSDH care within the United Kingdom. The outcomes of these discussions were recorded and summarised, before being circulated to all attendees for comment and refinement.

RESULTS

The working group identified four key requirements for improving cSDH care: (1) data, audit, and natural history; (2) evidence-based guidelines and pathways; (3) shared decision-making; and (4) an overarching quality improvement strategy. Frequent transfers between care providers were identified as impacting on both perioperative care and presenting a barrier to effective data collection and teamworking. Improvement initiatives must be cognizant of the complex, system-wide nature of the problem, and may require a combination of targeted trials at points of clinical equipoise (such as anesthetic technique or anticoagulant management), evidence-based guideline development, and a cycle of knowledge acquisition and implementation.

CONCLUSION

The care of cSDH is a growing clinical problem. Lessons may be learned from the standardised pathways of care such as those as used in hip fracture and stroke. A defined care pathway for cSDH, encompassing perioperative care and rehabilitation, could plausibly improve patient outcomes but work remains to tailor such a pathway to cSDH care. The development of such a pathway at a national level should be a priority, and the focus of future work.

Soil Enzyme Activity Behavior after Urea Nitrogen Application

Understanding how fertilizer application (particularly N, the most used chemical fertilizer worldwide) interacts with soil microbes is important for the development of best management practices that target improved microbial activity to enhance sustainable food production. This study was conducted to determine whether urea N rate and time of application to maize (Zea mays) influenced soil enzyme activity. Enzyme activity was determined by monitoring fluorescein diacetate (FDA) hydrolysis, ß-glucosidase, acid-phosphomonoesterase, and arylsulfatase activities. Experiments were conducted from 2014 through 2016 to compare single (fall or spring applications) and split applications of N at varying N rates under irrigation (Becker) and rainfed conditions (Lamberton and Waseca) in MN, USA. Nitrogen rates varied by location and were based on University of Minnesota guidelines. Soil samples were collected seven times each season. Nitrogen application split into two applications increased FDA activity by 10% compared with fall and spring applied N at Waseca. Fall or spring N application decreased arylsulfatase activity by 19% at Becker and by between 13% and 16% at Lamberton. ß-Glucosidase and acid-phosphomonoesterase activities were unaffected by N application. Sampling time and year had the greatest impact on enzyme activity, but the results varied by location. A negative linear relationship occurred between FDA and ß-glucosidase activity at all three sites. In summary, urea N application had small effects on enzyme activity at the sites studied, suggesting that some form of organic N could be more important than the ammonium provided by urea.

Can screening for degenerative cervical myelopathy (SCREEN-DCM) be effectively undertaken based on signs, symptoms and known risk factors? Rationale and research protocol for a prospective, multicentre, observational study

Introduction

Degenerative cervical myelopathy (DCM) is the most common cause of spinal cord impairment. Unfortunately, the condition remains poorly recognised and underdiagnosed. To better identify patients, screening tests that target individuals at high risk would be helpful. One group in particular known to have a high prevalence of DCM consists of patients with lumbar degenerative disease (LDD), with the combined presentation referred to as tandem stenosis. Given that LDD is one of the most common presentations in neurosurgical practice and primary care, it is the objective of the proposed study to administer a screening test to these patients as well as those with risk factors or symptoms which raise the suspicion of underlying DCM.

Methods and analysis

A screening test based on clinical signs/symptoms and known risk factors of DCM was designed. Screening will be performed in neurosurgical consultations for patients with LDD or those with any suspicion of myelopathy. Points are attributed based on the presence of signs/symptoms of DCM (eg, Hoffmann sign, hyper-reflexia) and for comorbidities that predispose or are frequently associated with cervical myelopathy (eg, rheumatoid arthritis, carpal tunnel syndrome). Patients with ≥3 points undergo cervical MRI examination. Patients with positive MRIs will be consulted and receive assessment via modified Japanese Orthopedic Association and Neck Disability Index scores, and subsequent clinical management will be based on practice guidelines. An exploratory multivariate analysis of the effectiveness and efficiency of this proposed screening test will be evaluated after positively screening 50 patients for DCM.

Ethics and dissemination

This study has received research ethics approval from the Swiss Association of Research Ethics Committees (ID: 2020-02785). The results of this study will be disseminated in a journal targeting physicians commonly encountering patients with LDD.

Exploring the contribution of mechano-sensing to cardiomyopathy

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Medical Research Council (MR/V009540/1),

Wellcome Trust (201543/B/16/Z)

British Heart Foundation (FS/12/40/29712).

Hypertrophic cardiomyopathy (HCM) is an inherited cardiac condition associated with diastolic dysfunction and sudden cardiac death. Disease genes for HCM are traditionally coding for proteins involved in force generation. More recently, it has emerged that variants in genes coding for proteins involved in biomechanical stress-signalling can also cause HCM.

One such protein is filamin C, with proposed mechano-sensing functions in the heart. Within the protein, the immunoglobulin-like domain 20 (Ig20) may play a crucial role in mediating binding to muscle specific ligands. While the mechano-sensing functions of filamin C have been investigated well in skeletal muscle, the underlying cardiac disease mechanisms are not completely understood.

Aim

This work attempts to provide insights into the role of filamin C in cardiac mechano-sensing and dissect disease pathways leading to HCM in the presence of the FLNC variants in Ig20.

Methods

Using mass spectrometry, we aimed to provide a detailed analysis of the proteome of mice carrying the filamin C variant, using ventricular tissue samples from 14wk old homozygous mice. Samples were subject to molecular biology technical and underwent subcellular fractionation (n = 6 per genotype) and were investigated by label-free mass spectrometry.

Results

Utilising whole genome sequencing, a heterozygous FLNC missense variant in Ig20 was identified in a three-generation family affected by HCM. Mice carrying this variant recapitulate molecular features of HCM in the homozygous setting. Three proteins (FLNC, MYH7, MYOT) were found to be upregulated in the myofilament-enriched fraction. Up-regulations of key proteins were found to relocalise towards load-baring sites.

Conclusion

Our data indicate that changes in filamin C and its binding partners expression and localisation are involved in the pathogenesis of HCM in this mouse model.

Crucial functions of alpha-actinin 2 in the embryonic heart

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Wellcome Trust; British Heart Foundation

Background/Introduction

Alpha-actinin is an integral protein of the Z-discs in heart and skeletal muscle cells, with important structural and signalling functions.  Missense variants in alpha-actinin can cause inherited conditions, e.g. myopathies and cardiomyopathies. The underlying disease mechanisms are still unknown.

Purpose

In order to study the disease mechanisms of an alpha-actinin missense variant, which is known to cause Hypertrophic Cardiomyopathy in human patients, a mouse model was generated.

Methods

Mice carrying the alpha-actinin missense variant were generated by CRISPR-Cas9 genome editing. The heterozygous adult mice carrying the alpha-actinin variant were characterised by echocardiography and quantitative PCR. Hearts of homozygous embryos were analysed at E15.5 by high-resolution episcopic microscopy (HREM).

Results

Mice carrying a single copy of the missense variant were viable and had normal appearance. Adult heterozygous mice showed no signs of cardiomyopathy on echocardiography. However, mature male mice displayed molecular signs of cardiomyopathy, such as induction of the fetal gene programme at transcript level.

The attempt to generate adult mice homozygous for the variant failed: 9 breeding pairs produced 18 litters with 83 weaned pups, but no homozygous offspring. Embryonic lethality was confirmed and E15.5 was the latest stage homozygous pups were reliably found to be viable. At this timepoint, genotype distribution was within the expected Mendelian ratios.

HREM of the hearts at this stage revealed increased right ventricular chamber size and decreased left atrial size, when compared to wildtype littermates. Membranous ventricular septal defects were observed in 3 out of 8 homozygous hearts. Further these embryos displayed aortic stenosis and dysplasic leaflets of the pulmonary valve.

Conclusions

Heterozygous adult mice only displayed sub-clinical signs of disease. In contrast, the missense variant is embryonic lethal in the homozygous setting and leads to a range of morphological abnormalities in E15.5 hearts. Future work will identify how altered functions of alpha-actinin cause these changes.

Do you know when the inhaler is empty?

BACKGROUND

Medication review is recommended at asthma appointments. The presence of propellant in the metered dose inhalers (MDIs) makes it challenging to identify when the inhaler is empty. The COVID-19 pandemic has resulted in move towards more virtual monitoring of care. We aimed to evaluate if patients identify when the inhaler is empty and the method of inhaler disposal.

METHODS

Prospective, multicentre quality improvement project. Data collected from children with asthma and other respiratory conditions.

OUTCOME MEASURES

Children/carers attending hospital were asked how they identify an empty salbutamol inhaler; dose counters in the preventer inhalers and disposal practices were reviewed.

RESULTS

157 patients recruited. 125 (73.5%) patients deemed an empty inhaler as either full/partially full. 12 of 66 (18.2%) preventer inhalers with a dose counter were empty. 83% disposed their inhalers in a dustbin.

CONCLUSIONS

Patients cannot reliably identify when their MDI is empty. There is an urgent need for improving inhaler technology and providing appropriate guidance on how to identify when an MDI is empty.

Lumbar decompression surgery for cauda equina syndrome - comparison of complication rates between daytime and overnight operating

PURPOSE

To investigate the incidence of complications from lumbar decompression ± discectomy surgery for cauda equina syndrome (CES), assessing whether time of day is associated with a change in the incidence of complications.

METHODS

Electronic clinical and operative notes for all lumbar decompression operations undertaken at our institution for CES over a 2-year time period were retrospectively reviewed. "Overnight" surgery was defined as any surgery occurring between 18:00 and 08:00 on any day. Clinicopathological characteristics, surgical technique, and peri/post-operative complications were recorded. Multivariable logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals.

RESULTS

A total of 81 lumbar decompression operations were performed in the 2-year period and analysed. A total of 29 (36%) operations occurred overnight. Complete CES (CESR) was seen in 13 cases (16%) in total, 7 of whom underwent surgery during the day. Exactly 27 complications occurred in 24 (30%) patients. The most frequently occurring complication was a dural tear (n = 21, 26%), followed by post-operative haematoma, infection, and residual disc. Complication rates in the CESR cohort (54%) were significantly greater than in the CES incomplete (CESI) cohort (25%) (p = 0.04). On multivariable analysis, overnight surgery was independently associated with a significantly increased complication rate (OR 2.83, CI 1.02-7.89).

CONCLUSIONS

Lumbar decompressions performed overnight for CES were more than twice as likely to suffer a complication, in comparison to those performed within daytime hours. Our study suggests that out-of-hours operating, particularly at night, must be clinically justified and should not be influenced by day-time operating capacity.

A Founder Mutation in EHD1 Presents with Tubular Proteinuria and Deafness

BACKGROUND

The endocytic reabsorption of proteins in the proximal tubule requires a complex machinery and defects can lead to tubular proteinuria. The precise mechanisms of endocytosis and processing of receptors and cargo are incompletely understood. EHD1 belongs to a family of proteins presumably involved in the scission of intracellular vesicles and in ciliogenesis. However, the relevance of EHD1 in human tissues, in particular in the kidney, was unknown.

METHODS

Genetic techniques were used in patients with tubular proteinuria and deafness to identify the disease-causing gene. Diagnostic and functional studies were performed in patients and disease models to investigate the pathophysiology.

RESULTS

We identified six individuals (5-33 years) with proteinuria and a high-frequency hearing deficit associated with the homozygous missense variant c.1192C>T (p.R398W) in EHD1. Proteinuria (0.7-2.1 g/d) consisted predominantly of low molecular weight proteins, reflecting impaired renal proximal tubular endocytosis of filtered proteins. Ehd1 knockout and Ehd1R398W/R398W knockin mice also showed a high-frequency hearing deficit and impaired receptor-mediated endocytosis in proximal tubules, and a zebrafish model showed impaired ability to reabsorb low molecular weight dextran. Interestingly, ciliogenesis appeared unaffected in patients and mouse models. In silico structural analysis predicted a destabilizing effect of the R398W variant and possible inference with nucleotide binding leading to impaired EHD1 oligomerization and membrane remodeling ability.

CONCLUSIONS

A homozygous missense variant of EHD1 causes a previously unrecognized autosomal recessive disorder characterized by sensorineural deafness and tubular proteinuria. Recessive EHD1 variants should be considered in individuals with hearing impairment, especially if tubular proteinuria is noted.

Tissue-Specific Roles for the Slit-Robo Pathway During Heart, Caval Vein, and Diaphragm Development

Background Binding of Slit ligands to their Robo receptors regulates signaling pathways that are important for heart development. Genetic variants in ROBO1and ROBO4 have been linked to congenital heart defects in humans. These defects are recapitulated in mouse models with ubiquitous deletions of the Slit ligands or Robo receptors and include additional heart defects not currently linked to SLIT or ROBO mutations in humans. Given the broad expression patterns of these genes, the question remains open which tissue-specific ligand-receptor interactions are important for the correct development of different cardiac structures. Methods and Results We used tissue-specific knockout mouse models of Robo1/Robo2, Robo4, Slit2 andSlit3 and scored cardiac developmental defects in perinatal mice. Knockout of Robo2 in either the whole heart, endocardium and its derivatives, or the neural crest in ubiquitous Robo1 knockout background resulted in ventricular septal defects. Neural crest-specific removal of Robo2 in Robo1 knockouts showed fully penetrant bicuspid aortic valves (BAV). Endocardial knock-out of either Slit2or Robo4 caused low penetrant BAV. In contrast, endocardial knockout of Slit3 using a newly generated line resulted in fully penetrant BAV, while removal from smooth muscle cells also resulted in BAV. Caval vein and diaphragm defects observed in ubiquitous Slit3 mutants were recapitulated in the tissue-specific knockouts. Conclusions Our data will help understand defects observed in patients with variants in ROBO1 and ROBO4. The results strongly indicate interaction between endocardial Slit3and neural crest Robo2 in the development of BAV, highlighting the need for further studies of this connection.