Epigenetic patterns in Atlantic herring (Clupea harengus): Temperature and photoperiod as environmental stressors during larval development

Understanding the molecular mechanisms underlying individual responses to environmental changes is crucial for species conservation and management. Pelagic fishes including Atlantic herring (Clupea harengus) are of particular interest because of their key ecological and economic roles and their susceptibility to a changing ocean from global warming. Temperature and photoperiod have been linked with spawning time and location in adult herring, but no study has thus far investigated the role of environmental factors on gene regulation during the vulnerable early developmental stages. Here, we examine DNA methylation patterns of larval herring bred under two temperatures (11°C and 13°C) and photoperiod (6 and 12 h) regimes in a 2 × 2 factorial design. We found consistently high levels of global methylation across all individuals and a decline in global methylation with increased developmental stage that was more pronounced at 13°C (p ≤ 0.007) than at 11°C (p ≥ 0.21). Most of the differentially methylated sites were in exon and promoter regions for genes linked to metabolism and development, some of which were hypermethylated at higher temperature. These results demonstrate the important role of DNA methylation during larval development and suggest that this molecular mechanism might be key in regulating early-stage responses to environmental stressors in Atlantic herring.

775 Role of Inversion Imaging in the Diagnoses of Neck of Femur Fractures

Aim

The objective of this study was to assess whether inversion of grey scale radiograph images has any impact on the diagnostic sensitivity and inter-observer reliability in diagnosing neck of femur fractures.

Method

We performed a retrospective, single centre study, using 50 randomly selected AP pelvis radiographs. The images included a combination of normal, intracapsular and extracapsular neck of femur fractures, which had been confirmed on CT, MRI and/or subsequent surgery.

Four independent observers (two orthopaedic specialists, one registrar and one SHO in orthopaedics) reviewed the images and graded each radiograph image using the Likert scale in response to the statement “there is a fracture”. Following this, the same radiographs were inverted to grey scale images and sent for a second review using the same method. RAND correlation was used for statistical analysis.

Results

Overall, observers appeared to have similar accuracy and equivocal rates with normal and inversion radiographic imaging.

One of the T&O Consultant's had much higher equivocal rate when analysing inverted radiographs compared to conventional digital radiographs but had slightly higher accuracy with inversion (95.35% compared to 93.88%) as well as the Registrar (83.33% compared to 81.63%). The second Trauma and Orthopaedics Consultant had slightly more accuracy with conventional digital radiographs (89.58% compared with 87.50%).

Conclusions

Inversion of digital radiographs did not affect the diagnostic sensitivity of neck of femur fractures in our study, and similarly did to not have a statistically significant impact in clinician confidence in diagnosing neck of femur fractures.

Ultrasound assessment of the hamstrings complex of athletes with MRI correlation

Due to anatomical complexity, ultrasound examination of the hamstring muscles is challenging, resulting in potential diagnostic uncertainty and under-confidence in the technique. This leads to a subsequent tendency to favour magnetic resonance imaging (MRI) evaluation, which can delay diagnosis and potential intervention. This article describes a comprehensive technique of ultrasound evaluation of the hamstrings complex, using key anatomical landmarks. A direct comparison of the sonographic landmarks with corresponding MRI appearances is also provided. If these landmarks can be identified successfully, the complex anatomy can be unlocked, thus improving the time and sensitivity of diagnosis of acute injuries, as well as providing a reliable framework for monitoring injury progress and helping to identify candidates for potential intervention. Many of the anatomical landmarks discussed are common areas of injury in elite athletes, encountered frequently in clinical practice.

Development, evaluation and validation of machine learning algorithms to detect atypical and asymptomatic presentations of Covid-19 in hospital practice

BACKGROUND

Diagnostic methods for Covid-19 have improved, both in speed and availability. Because of atypical and asymptomatic carriage of the virus and nosocomial spread within institutions, timely diagnosis remains a challenge. Machine learning models trained on blood test results have shown promise in identifying cases of Covid-19.

AIMS

To train and validate a machine learning model capable of differentiating Covid-19 positive from negative patients using routine blood tests and assess the model's accuracy against atypical and asymptomatic presentations.

DESIGN AND METHODS

We conducted a retrospective analysis of medical admissions to our institution during March and April 2020. Participants were categorized into Covid-19 positive or negative groups based on clinical, radiological features or nasopharyngeal swab. A machine learning model was trained on laboratory parameters and validated for accuracy, sensitivity and specificity and externally validated at an unconnected establishment.

RESULTS

An Ensemble Bagged Tree model was trained on data collected from 405 patients (212 Covid-19 positive) producing an accuracy of 81.79% (95% confidence interval (CI) 77.53-85.55%), the sensitivity of 85.85% (CI 80.42-90.24%) and specificity of 76.65% (CI 69.49-82.84%). Accuracy was preserved for atypical and asymptomatic subgroups. Using an external data set for 226 patients (141 Covid-19 positive) accuracy of 76.82% (CI 70.87-82.08%), sensitivity of 78.38% (CI 70.87-84.72%) and specificity of 74.12% (CI 63.48-83.01%) was achieved.

CONCLUSION

A machine learning model using routine laboratory parameters can detect atypical and asymptomatic presentations of Covid-19 and might be an adjunct to existing screening measures.

1547 An Alternative Approach to High-Risk Resternotomy

Introduction

Resternotomies are associated with substantial perioperative morbidity and mortality. Strategies described in literature mostly involve peripheral cannulation pre-sternotomy. Disadvantages of this technique relate to prolonged systemic heparinisation and cardiopulmonary bypass (CPB) time and the sequelae of hypothermic circulatory arrest. We describe a two-stage approach that potentially reduces the complications associated with high-risk resternotomy.

Method

3 high-risk patients (from pre-operative CT images) were referred for redo complex aortic surgery. A right mini-thoracotomy incision was first made in the 4th or 5th intercostal space. The right lung was isolated and careful blunt dissection was carried out to mobilise the heart and great vessels attached to the sternum. Once these structures were free, thoracotomy incision was closed. A standard median sternotomy was then performed and central cannulation carried out after systemic heparinisation. Rest of the surgery was performed routinely. In one patient, aortic aneurysm was heavily adherent and attempts to mobilise it fully proved impossible. Resultantly, systemic heparinisation was administered and the patient was cannulated in the right superficial femoral artery and right atrium (via mini-thoracotomy). CPB was instituted and the patient cooled to 28 °C. Right superior pulmonary vein vent was introduced to prevent left ventricular distension from hypothermic ventricular fibrillation. Once the heart and aneurysm were decompressed on full CPB, complete mobilisation was performed safely. All 3 patients survived surgery without major complications.

Conclusions

Meticulous preoperative planning is key to management of high-risk resternotomy. We describe a novel technique which we believe minimises risk of morbidity and mortality in these complex cases.

Birmingham Intervention Tent Technique (BITT): A Technical Note

Objective We describe a novel and safe CT biopsy technique that we have termed the “Birmingham intervention tent technique (BITT).” This technique is ideal for biopsying osseous lesions where a direct approach is not possible due to difficult positioning.

Methods The BITT uses a plastic surgical forceps clamp attached at an angle to the biopsy needle, creating a tent shape. The finger rings of the forceps is stabilized on the table.

Results In our institution, we have already used the BITT successfully in over 10 cases.

Conclusion The BITT is an inexpensive and reproducible technique.

Elevated procalcitonin concentrations in severe Covid-19 may not reflect bacterial co-infection

BACKGROUND

The variability of Covid-19 severity between patients has driven efforts to identify prognosticating laboratory markers that could aid clinical decision-making. Procalcitonin is classically used as a diagnostic marker in bacterial infections, but its role in predicting Covid-19 disease severity is emerging. We aimed to identify the association between procalcitonin and Covid-19 disease severity in a critical care setting and whether bacterial co-infection is implicated.

METHODS

We retrospectively reviewed Covid-19 patients with procalcitonin concentrations measured in a critical care setting at our institution between February and September 2020. Laboratory markers including peak procalcitonin values and a range of bacterial culture results were analysed. Outcomes were the requirement and duration of invasive mechanical ventilation as well as inpatient mortality.

RESULTS

In total, 60 patients were included; 68% required invasive mechanical ventilation and 45% died as inpatient. Univariate analysis identified higher peak procalcitonin concentrations significantly associated with both the requirement for invasive mechanical ventilation (OR: 3.2, 95% CI 1.3-9.0, P = 0.02) and inpatient mortality (OR: 2.6, 95% CI 1.1-6.6, P = 0.03). Higher peak procalcitonin concentrations was an independent predictor of mortality on multivariate analysis (OR 3.7, 95% CI 1.1-12.4, P = 0.03). There was a significant positive correlation between increased peak procalcitonin concentrations and duration on invasive mechanical ventilation. No significant difference was found between peak procalcitonin concentrations of patients with positive and negative bacterial cultures.

CONCLUSIONS

Elevated procalcitonin concentrations in Covid-19 patients are associated with respiratory failure requiring prolonged invasive mechanical ventilation and inpatient mortality. This association may be independent of bacterial co-infection.

Atypical presentation of COVID-19 in hospitalised older adults

Background

It is increasingly recognised that older patients may not present with typical symptoms of COVID-19.

Aims

This study aims to evaluate the incidence, characteristics and clinical outcome of older adults with atypical presentations of COVID-19.

Methods

A retrospective analysis of adults ≥ 65 years with confirmed COVID-19 admitted to our institution between 1 March and 24 April 2020 was performed. Patients were categorised into typical or atypical groups based on primary presenting complaint in the community.

Results

One hundred twenty-two patients (mean age 81 ± 8 years; 62 male) were included. Seventy-three (60%) were categorised into the typical group and 49 (40%) into the atypical group. In the atypical group, common presenting complaints were fall in 18 (36%), reduced mobility or generalised weakness in 18 (36%) and delirium in 11 (22%). Further assessment by paramedics and on admission found 32 (65%) to have typical features of COVID-19, fever being the most common, and 22 (44%) were hypoxic. This subset had worse outcomes than those in the typical group with a mortality rate of 50% versus 38%, respectively, although this was not statistically significant (P = 0.27). No significant difference in mortality or length of hospital stay between the groups was demonstrated.

Conclusion

Older patients with atypical presentation of COVID-19 in the community are equally susceptible to poor outcomes. Early detection may improve outcomes and limit community transmission. Primary care practitioners should be vigilant and consider prompt onward referral.

Hamstring origin-anatomy, angle of origin and its possible clinical implications

INTRODUCTION

The posterior compartment of the thigh is composed of three major muscles collectively known as the hamstring muscles. These consist of the biceps femoris short and long head, semimembranosus and semitendinosus. Excluding the short head of biceps femoris, the hamstrings contribute to the movement of the hip and the knee joints as they span across both joints. Our hypothesis is that the nature of the conjoint tendon -ischial angle predisposes to an increased risk of tearing in this hamstring component. We therefore aim to look at the anatomy of the hamstring origin at the ischial tuberosity and spatial relationship between the long head of biceps, semitendinosus and semimembranosus in the form of vector angles.

MATERIAL AND METHODS

100 consecutive pelvic MRIs in patients under the age of 40 years were reviewed by musculoskeletal radiology fellow and a consultant musculoskeletal radiologist with more than 10 years' experience in musculoskeletal radiology and measured the angle of origin of conjoined tendon and semimembranosus at its ischial origin. P value using a paired t-test was less than 0.0001 confirming that the difference in the vector angle of the different hamstring components was statistically significant.

RESULTS

The median angle of origin of conjoined tendon was 12° and for semimembranosus was 6°. Applying the concept of Newton's second law to the angles calculated we demonstrated that an increase of 9% force applied to the conjoint tendon origin when compared to the semimembranosus tendon.

CONCLUSION

We hypothesis that the difference in the angle of origin of the components of hamstrings might be one of the reasons for the difference in the incidence and patterns of the injuries of the various muscles of the hamstrings.

A Review on the Surgical Management of Intramural Haematoma of the Aorta

Intramural haematoma (IMH) of the aorta is one of the causes of acute aortic syndrome which often requires emergency or urgent life-saving surgery. In this review, we discuss the pathophysiology, epidemiology, clinical presentation, diagnostic imaging, surgery and clinical outcomes associated with IMH.

MRI assessment of anatomy and pathology of the iliofemoral ligament

The iliofemoral ligament is strongest ligament of the body. We review the magnetic resonance imaging (MRI) appearances of the iliofemoral ligament, and discuss the disease entities that may affect this region.

Pulmonary embolism in COVID-19: Clinical characteristics and cardiac implications

BACKGROUND

The thrombogenic potential of Covid-19 is increasingly recognised. We aim to assess the characteristics of COVID-19 patients diagnosed with pulmonary embolism (PE).

METHODS

We conducted a single centre, retrospective observational cohort study of COVID-19 patients admitted between 1st March and 30th April 2020 subsequently diagnosed with PE following computed tomography pulmonary angiogram (CTPA). Patient demographics, comorbidities, presenting complaints and inpatient investigations were recorded.

RESULTS

We identified 15 COVID-19 patients diagnosed with PE (median age = 58 years [IQR = 23], 87% male). 2 died (13%), both male patients >70 years. Most common symptoms were dyspnoea (N = 10, 67%) and fever (N = 7, 47%). 12 (80%) reported 7 days or more of non-resolving symptoms prior to admission. 7 (47%) required continuous positive airway pressure (CPAP), 2 (13%) of which were subsequently intubated. All patients had significantly raised D-dimer levels, lactate dehydrogenase (LDH), C-reactive protein (CRP), ferritin and prothrombin times. The distribution of PEs correlated with the pattern of consolidation observed on CTPA in 9 (60%) patients; the majority being peripheral or subsegmental (N = 14, 93%) and only 1 central PE. 10 (67%) had an abnormal resting electrocardiogram (ECG), the commonest finding being sinus tachycardia. 6 (40%) who underwent transthoracic echocardiography (TTE) had structurally and functionally normal right hearts.

CONCLUSION

Our study suggests that patients who demonstrate acute deterioration, a protracted course of illness with non-resolving symptoms, worsening dyspnoea, persistent oxygen requirements or significantly raised D-dimer levels should be investigated for PE, particularly in the context of COVID-19 infection. TTE and to a lesser degree the ECG are unreliable predictors of PE within this context.

Long term use of donepezil and QTc prolongation

BACKGROUND

The neurocognitive benefits of donepezil are well recognised, but the potential side effects on cardiac conduction remain unclear.

OBJECTIVE

To investigate whether long-term donepezil therapy is associated with electrocardiographic (ECG) changes and in particular to assess its effects on the QT interval.

METHODS

We conducted a single centre retrospective analysis of patients admitted to our trust on donepezil therapy over a 12-month period. An admission resting 12-lead ECG was obtained and compared to their ECG prior to commencement of donepezil therapy to assess for any significant difference in ECG parameters.

RESULTS

We identified 59 patients suitable for analysis. PR (177.0 ± 29.0 ms vs. 186.1 ± 34.2 ms, p = 0.04), QRS (101.7 ± 20.3 ms vs. 104.7 ± 22.3 ms, p = 0.04) and QT (393.3 ± 35.6 ms vs. 411.9 ± 44.6 ms, p = 0.002) interval prolongation were all associated with donepezil use. The increase in QT intervals remained significant on correction for heart rate; resulting in 8 (13.6%) patients developing high arrhythmogenic risk based on assessment using QT nomogram plots. Concomitant use of tricyclic antidepressants was associated with significant QT prolongation (QTcB: r _pb = 0.344, p = 0.008, QTcFred: r _pb = 0.382, p = 0.003, QTcFram: r _pb = 0.379, p = 0.003, QTcH: r _pb = 0.352, p = 0.006), while the use of rate-limiting calcium channel blockers was associated with significant PR prolongation (r _pb = 0.314, p = 0.030), and beta-blockers with a reduction in heart rate (r _pb = 0.256, p = 0.050).

CONCLUSION

Our results clearly demonstrate that long-term use of donepezil is associated with prolongation of the QT interval. We suggest ECG evaluation should take place before and after donepezil initiation, and clinicians should be even more vigilant in those prescribed tricyclic antidepressants.

Permanent pacemaker implantation rates following cardiac surgery in the modern era

AIMS

The aim of this study was to evaluate the incidence of permanent pacemaker (PPM) implantation after cardiac surgery in our institution and investigate risk factors for PPM dependency to provide patients with accurate incidence figures at the time of consent for surgery.

METHODS

Data was collected retrospectively from a single tertiary institution from October 2018 to April 2019 inclusive of 403 patients. Incidence of PPM implantation after various cardiac operations was evaluated. A univariate analysis was carried out to identify the independent risk factors related to PPM implantation.

RESULTS

Ten patients required a PPM (2.48%). The most common indication for PPM implantation post-cardiac surgery was complete heart block (N = 7, 70%) followed by bradycardia/pauses (N = 2, 20%) and sick sinus syndrome (N = 1, 10%). PPM implantation after coronary artery bypass graft (CABG) surgery was the lowest (0.63%), while combined CABG and valve operations had the highest incidence (5.97%). Independent risk predictors for PPM implantation included female gender (p = 0.03), rheumatic heart disease (p = 0.008), pulmonary hypertension (p = 0.01), redo operations (p = 0.002), mitral valve procedures (p = 0.001), tricuspid valve procedures (p = 0.0003) and combined mitral and tricuspid valve procedures (p = 0.0001). Average length of intensive care unit (ICU)/high-dependency unit (HDU) stay was significantly prolonged for patients who required a PPM post-cardiac surgery.

CONCLUSION

As clinicians, it can be challenging to provide our patients with accurate information on the risk of PPM implantation relative to their operation. A unit-specific data may be a more accurate method of informing our patients on this risk.

Anatomy and pathology of facet joint

Facet joints are the only synovial joints in the spine and can be involved in a large number of pathological processes including arthropathy, infection, inflammation, trauma and tumour. In this review article, we present a spectrum of pathologies that arise from or involve facet joints that we have encountered in our tertiary orthopaedic and spinal centre. The objective of this review is to create an aide memoire for the general radiologist who may encounter facet joint pathology, which they may not be familiar with.

Construction of a novel expression cassette for increasing transgene expression in vivo in endothelial cells of large blood vessels

The success of gene therapy hinges on achievement of adequate transgene expression. To ensure high transgene expression, many gene-therapy vectors include highly active virus-derived transcriptional elements. Other vectors include tissue-specific eukaryotic transcriptional elements, intended to limit transgene expression to specific cell types, avoid toxicity and prevent immune responses. Unfortunately, tissue specificity is often accompanied by lower transgene expression. Here, we use eukaryotic (murine) transcriptional elements and a virus-derived posttranscriptional element to build cassettes designed to express a potentially therapeutic gene (interleukin (IL)-10) in large-vessel endothelial cells (ECs) at levels as high as obtained with the cytomegalovirus (CMV) immediate early promoter, while retaining EC specificity. The cassettes were tested by incorporation into helper-dependent adenoviral vectors, and transduction into bovine aortic EC in vitro and rabbit carotid EC in vivo. The murine endothelin-1 promoter showed EC specificity, but expressed only 3% as much IL-10 mRNA as CMV. Inclusion of precisely four copies of an EC-specific enhancer and a posttranscriptional regulatory element increased IL-10 expression to a level at or above the CMV promoter in vivo, while retaining--and possibly enhancing--EC specificity, as measured in vitro. The cassette reported here will likely be useful for maximizing transgene expression in large-vessel EC, while minimizing systemic effects.

Digital measurement of torsional eye movement due to postural change and its effect on reading performance

PURPOSE

Posture induced torsional eye movements have rarely been investigated. The current study made use of digital imaging technology to measure the cycloduction resulting from postural change. The effect of cycloduction on reading performance was also investigated.

METHODS

Thirty subjects were recruited and pictures of the right eye were captured using a digital camera at three postures, i.e. sitting, 90 degrees tilted to the right and 90 degrees tilted to the left. With the identification of a conjunctival landmark, torsional eye movement was measured. The subjects were then required to read a custom designed near chart while in those three postures, the reading card being rotated 90 degrees clockwise or 90 degrees anti-clockwise, to match with the tilting of the head. The reproducibility of the torsional eye movement and reading performance measure was determined in 12 of those 30 subjects.

RESULTS

Incycloduction was induced when tilting to the right and excycloduction when tilting to the left. This method was found to be reproducible with the 95% confidence limits of 0.80 degrees between visits. The mean incycloduction induced was 6.50 degrees (SD 1.51 degrees ) and 6.41 degrees (SD 1.46 degrees ) for excycloduction. No significant difference in amount was demonstrated (paired t-test: t = 0.624, P = 0.538). No significant difference was found in the reading scores at various postures (Repeated measures ANOVA: df = 2, F = 1.881, P = 0.162).

CONCLUSIONS

The results presented here demonstrate that we have developed an objective and instantaneous method with good precision, which could be applied in other studies that require the measurement of torsional eye movements. The induced cycloduction did not affect the reading performance.

Confirmation of the hierarchical folding of RNase H: a protein engineering study

The kinetic intermediate of RNase H is structured in a core region of the protein. To probe the role of this intermediate in the folding of RNase H, the folding kinetics of mutant proteins with altered native state stabilities were investigated. Mutations within the folding core destabilize the kinetic intermediate and slow refolding in a manner consistent with an obligatory intermediate model. Mutations outside of the folding core, however, do not affect the stability of the kinetic intermediate but do perturb the native state and transition state. These results indicate that interactions formed in the intermediate persist in the transition and native states and that RNase H folds through a hierarchical mechanism.

Fine needle aspiration cytology of benign adrenal cortical nodules. A comparison of cytologic findings with those of primary and metastatic adrenal malignancies

OBJECTIVE

To determine the specific cytomorphologic criteria for diagnosing benign adrenal cortical nodule (BACN) by fine needle aspiration (FNA).

STUDY DESIGN

The smears from 162 adrenal FNA biopsies were reviewed. A diagnosis of BACN was rendered in 50 cases (31%). The cytologic features of BACN were compared to those of primary and metastatic malignant tumors of the adrenal gland, and the size of BACN as measured by computed tomography was recorded.

RESULTS

Bubbly, vacuolated, lipid background; large, cohesive tissue fragments with a syncytial nesting arrangement admixed with sinusoidal endothelial cells; and abundant oval, round, bare nuclei are the three cytomorphologic features most often seen in BACN. The combination of these three features was observed in 40 cases (89%) of BACN and was seen in 4 cases of metastatic carcinoma (6%) in which there was also coexisting adrenal cortical hyperplasia. None of the other primary or metastatic malignancies showed this combination of cytomorphologic features. The mean size of BACN was 2.5 cm, with a standard deviation of 1 cm and a range of 1-5 cm. The sizes of the four metastatic carcinomas with coexisting adrenal cortical hyperplasia were 6.5, 6, 5 and 1.5 cm, respectively (mean, 4.8).

CONCLUSION

Our data suggest that combined cytologic features of bare nuclei; bubbly, vacuolated background; and large, cohesive tissue fragments with sinusoidal endothelial cells in a small adrenal nodule (< 3.5 cm) are highly specific to FNA diagnosis of BACN.

Composite pleomorphic xanthoastrocytoma and ganglioglioma: report of four cases and review of the literature

Composite pleomorphic xanthoastrocytoma (PXA)-ganglioglioma (GG) is a rare recently described entity. Only three examples have been documented, one of which showed evidence of malignant transformation. We report an additional four cases and update the literature. With the exception of an 82-year-old man, all patients have been under 30 years of age. The temporal lobe was involved in three cases and cerebellum in another three. Radiologic features were those common to PXA and GG. Histologically, all were "collision tumors" composed of abutting, although spatially distinct, PXA and GG components. In two cases, the second element was only recognized at reexcision or recurrence. Histologic anaplasia, always in the PXA component, was evident as brisk mitotic activity and/or necrosis in five cases. Of the seven patients, one died of disease 17 years after the onset of seizures and after multiple recurrences, the last of which largely resembled glioblastoma. We conclude that the composite PXA-GG is a rare neoplasm that shares many features of its individual components. In addition to its temporal lobe predilection, the cerebellum is frequently affected. As when it occurs in isolation, the PXA component of composite PXA-GG possesses the potential for malignant transformation.