Risk factors for complications after emergency surgery for paediatric appendicitis: a national prospective observational cohort study

Appendicectomy is a common procedure in children with a low risk of mortality, however, complication rates and risk factors are largely unknown. This study aimed to characterise the incidence and epidemiology of postoperative complications in children undergoing appendicectomy in the UK. This multicentre prospective observational cohort study, which included children aged 1-16 y who underwent surgery for suspected appendicitis, was conducted between November 2019 and January 2022. The primary outcome was 30-day postoperative morbidity. Data collected included: patient characteristics; comorbidities; and physiological status. Multivariable regression analysis was used to identify independent risk factors for poor outcomes. Data from 2799 children recruited from 80 hospitals were analysed, of which 185 (7%) developed postoperative complications. Children from black and 'other' minority ethnic groups were at significantly higher risk of poor outcomes: OR (95%CI) 4.13 (1.87-9.08), p < 0.001 and 2.08 (1.12-3.87), p = 0.021, respectively. This finding was independent of socio-economic status and type of appendicitis found on histology. Other risk factors for complications included: ASA physical status ≥ 3 (OR (95%CI) 4.05 (1.70-9.67), p = 0.002); raised C-reactive protein (OR 95%CI 1.01 (1.00-1.01), p < 0.001); pyrexia (OR (95%CI) 1.77(1.20-2.63), p = 0.004); and peri-operative oxygen supplementation (OR (95%CI) 4.20 (1.44-12.24), p = 0.009). In the UK NHS, which is a universally accessible healthcare system, ethnicity, but not socio-economic status, was associated with an increased risk of postoperative complications in children having surgery for acute appendicitis. Further evaluations and interventions are required to address this health inequality in keeping with NHS and international priorities.

Adenosine A1R/A3R agonist AST-004 reduces brain infarction in mouse and rat models of acute ischemic stroke

Acute ischemic stroke (AIS) is the second leading cause of death globally. No Food and Drug Administration (FDA) approved therapies exist that target cerebroprotection following stroke. Our group recently reported significant cerebroprotection with the adenosine A1/A3 receptor agonist, AST-004, in a transient stroke model in non-human primates (NHP) and in a preclinical mouse model of traumatic brain injury (TBI). However, the specific receptor pathway activated was only inferred based on in vitro binding studies. The current study investigated the underlying mechanism of AST-004 cerebroprotection in two independent models of AIS: permanent photothrombotic stroke in mice and transient middle cerebral artery occlusion (MCAO) in rats. AST-004 treatments across a range of doses were cerebroprotective and efficacy could be blocked by A3R antagonism, indicating a mechanism of action that does not require A1R agonism. The high affinity A3R agonist MRS5698 was also cerebroprotective following stroke, but not the A3R agonist Cl-IB-MECA under our experimental conditions. AST-004 efficacy was blocked by the astrocyte specific mitochondrial toxin fluoroacetate, confirming an underlying mechanism of cerebroprotection that was dependent on astrocyte mitochondrial metabolism. An increase in A3R mRNA levels following stroke suggested an intrinsic cerebroprotective response that was mediated by A3R signaling. Together, these studies confirm that certain A3R agonists, such as AST-004, may be exciting new therapeutic avenues to develop for AIS.

Search for Dark Matter Axions with CAST-CAPP

The CAST-CAPP axion haloscope, operating at CERN inside the CAST dipole magnet, has searched for axions in the 19.74 μeV to 22.47 μeV mass range. The detection concept follows the Sikivie haloscope principle, where Dark Matter axions convert into photons within a resonator immersed in a magnetic field. The CAST-CAPP resonator is an array of four individual rectangular cavities inserted in a strong dipole magnet, phase-matched to maximize the detection sensitivity. Here we report on the data acquired for 4124 h from 2019 to 2021. Each cavity is equipped with a fast frequency tuning mechanism of 10 MHz/ min between 4.774 GHz and 5.434 GHz. In the present work, we exclude axion-photon couplings for virialized galactic axions down to g_aγγ = 8 × 10⁻¹⁴ GeV⁻¹ at the 90% confidence level. The here implemented phase-matching technique also allows for future large-scale upgrades.

Haloscopes aim at detecting axions by converting them into photons using high-quality resonant cavities, where the cavity resonance should be tuned with the unknown axion mass. Here, the authors improve exclusion limits using four phase-matched resonant cavities and a fast frequency scanning technique.

SP10.1.3 The presentation, management and outcomes of acute appendicitis: a comparison of patients presenting during the COVID-19 pandemic and those presenting in a pre-COVID-19 period

Aims

This study assesses the impact of COVID-19 on the presentation and management of acute appendicitis (AA). Patients presenting with AA during the first wave of the COVID-19 pandemic are compared to a pre-COVID-19 cohort.

Methods

Patients admitted to a single acute NHS hospital with AA between April and July in 2019 and 2020 were retrospectively identified. Data on presentation, treatment and outcomes was collected.

Results

56 patients were identified in 2019, and 37 in 2020. A greater proportion of patients presented later (&gt;3 days of symptoms) in 2020 (2019=15.6%, 2020=32.4%, p &lt; 0.05). There was no significant difference in the proportion of patients presenting systemically unwell (pyrexial & tachycardic) or with high inflammatory markers (CRP &gt; 50 and white cell count &gt; 15). In 2020, more patients were managed conservatively (2019=7.1%, 2020=35.1%, p &lt; 0.05). Among those who were managed operatively, 75% underwent open appendicectomy in 2020, compared to 7.7% (including cases converted to open from laparoscopic) in 2019. Patients managed operatively during the COVID-19 pandemic had significantly more post-operative complications (2019=17.3%, 2020=50%, p &lt; 0.05). Common post-operative complications in 2020 were abdominal collections (16.7%) and wound infections (12.5%). Median duration of admission was similar (2019=3 days, 2020=2 days) and there was no significant difference in 30-day readmissions (2019=8.9%, 2020=13.5%, p = 0.48).

Conclusions

AA patients in the COVID-19 pandemic were more likely to present later and were more likely to be managed conservatively or with open appendicectomy. There was a higher rate of post-operative complications for patients in 2020. Duration of stay and readmission rates were similar.

767 Magnetic Resonance Imaging in the Assessment of Patients with Breast Cancer Undergoing Neoadjuvant Chemotherapy: Evaluation of the Prognostic Value of Mid-Chemotherapy and Post-Chemotherapy Scans

Introduction

Magnetic Resonance Imaging (MRI) is used to assess the response to Neoadjuvant Chemotherapy (NAC) when used in patients with breast cancer.

Method

This retrospective observational study compared patterns of tumour response at mid-chemotherapy and post-chemotherapy MRIs to histological outcomes. 118 cases of breast cancer, from a local database, were included.

Results

There was a significant association between complete pathological response in resected breast tissue and complete radiological response on both mid-chemotherapy MRI (p = 0.007) and post-chemotherapy MRI (p &lt; 0.001). In patients who had both scans,100% of those with complete response at mid-chemotherapy scan maintained this response pattern. In those who had both scans, complete response at the mid-chemotherapy scan had a PPV for complete pathological response in resected breast tissue of 92% compared to 64% in those with complete response that was not achieved until the post-chemotherapy scan. There was a trend towards an association between early complete radiological response and complete pathological response (p = 0.124).

Conclusions

Both scans have significant prognostic value. A mid-chemotherapy scan may have superior prognostic value when complete response is achieved, though larger studies are needed to determine the significance. 100% maintenance of complete radiological response after the mid-chemotherapy scan highlights the possibility that some post-chemotherapy scan could be avoided.

Estrogen and sex-dependent loss of the vocal learning system in female zebra finches

Sex hormones alter the organization of the brain during early development and coordinate various behaviors throughout life. In zebra finches, song learning is limited to males, with the associated song learning brain pathways only maturing in males and atrophying in females. While this atrophy can be prevented by treating females with exogenous estrogen during early post-hatch development, the requirement of estrogen during normal male song system development is uncertain. For the first time in songbirds, we administered exemestane, a potent third generation estrogen synthesis inhibitor, from the day of hatching until adulthood in order to reassess the role of estrogen in song circuit development. We examined the behavior, brain anatomy, and transcriptomes of individual song nuclei in these pharmacologically manipulated animals. We found that males with long-term exemestane treatment had diminished male-specific plumage and impaired song learning, but minimal effect on song nuclei sizes and their specialized transcriptome. Consistent with prior findings, females with long-term estrogen treatment retained a functional song system with song nuclei that had specialized gene expression similar, but not identical to males. We also observed that different song nuclei responded to estrogen manipulation differently, with Area X in the striatum being the most altered by estrogen modulation. These findings support the hypothesis that song learning is an ancestral trait in both sexes that was subsequently suppressed in females of some species and that estrogen has come to play a critical role in modulating this suppression as well as refinement of song learning.

Optimizing the Availability of Enhanced Prehospital Care Team Resources

OBJECTIVE

After recent developments within the North West Air Ambulance (NWAA), we undertook a service evaluation to determine if resource use could be improved. We sought to answer the following questions: (1) At what time of day do major trauma incidents occur in the North West of England? 2) Do current NWAA operating hours meet the needs of these major trauma patients? 3) Where do major trauma incidents occur in the North West of England? and 4) Are current NWAA resources optimally located to meet the needs of these major trauma patients?

METHODS

We reviewed records from the Trauma Audit and Research Network database for the North West of England (the counties of Cheshire, Merseyside, Greater Manchester, Cumbria, and Lancashire) between January 1, 2017, and December 31, 2017. These data were supplemented by incident records from the North West Ambulance Service National Health Service Trust. Analysis was undertaken using Excel (Microsoft, Redmond, WA) and MapInfo Pro (Pitney Bowes, Stamford, CT). A survey will be conducted to give insight into the level of cover provided by other UK helicopter emergency medical services.

RESULTS

Data from 2,318 incidents were analyzed. Major trauma occurs in higher numbers at certain times of day, varies from weekday to weekend, and takes place in higher concentrations in certain locations, appearing related to population density.

CONCLUSION

There is a significant difference between the current trauma care provision and the demand of major trauma incidents. The findings of this study suggest an expansion in cover provided by the NWAA may be appropriate.

0922 Nightly Associations Between Pre-Bedtime Activity, Actigraphic Light, and Sleep in Children With ASD and Insomnia

Introduction

Approximately two thirds of children with Autism Spectrum Disorder (ASD) suffer from chronic insomnia. Current behavioral interventions for insomnia in children with ASD use sleep hygiene guidelines to educate parents and their children regarding sleep promoting habits. However, the relationship between pre-bedtime physical activity/light and sleep is understudied in ASD. The current study examined daily associations between pre-bedtime actigraphically assessed activity/light levels and objective/subjective sleep outcomes in children with ASD and insomnia.

Methods

Thirty children (Mage=8.5 yrs, SD=1.78 yrs) with comorbid ASD and insomnia completed 14 days of actigraphy measuring ambient white light intensity and activity levels every 30 seconds. Validated sleep scoring algorithms (in Actiware V. 6.0.9) estimated objective sleep onset latency (SOL), total sleep time (TST), wake time after sleep onset (WASO), and average activity/light levels 30, 60, and 120 mins prior to bedtime. Additionally, average activity/light levels 120-240, and 240-360 mins prior to bedtime were computed. Children also completed 14 daily sleep diaries (with parental assistance) measuring subjective reports of the same sleep parameters. Associations between daily estimations of pre-bedtime activity levels, light, and nighttime objective and subjective sleep were examined through multilevel modelling. Bonferroni corrections were performed to account for multiple comparisons.

Results

After Bonferroni corrections (p&lt;.025 significance level), greater activity within 30 minutes (B=0.0465, p=.0093) and 60 minutes (B=0.0681, p=.0005) of bedtime were associated with longer subjective SOL. Pre-bedtime light exposure was not a significant predictor of sleep outcomes.

Conclusion

Results suggest that in general, variations in daily pre-bedtime activity, but not light, are associated with worse nightly subjective SOL in children with ASD and insomnia. Findings support that sleep hygiene recommendations in children with ASD include avoidance of higher levels of pre-sleep physical activity. Prospective studies examining temporal causal relationships between pre-bedtime activity and sleep in ASD are warranted.

Support

Research was supported by a University of Missouri Research Board award (McCrae, PI; Mazurek, Co-PI). Data collected as part of clinical trial NCT02755051 Targeting Sleep in Kids with Autism Spectrum Disorder at the University of Missouri (PI: McCrae).

Pharmacologic and non-pharmacologic interventions to prevent hypersensitivity reactions of non-ionic iodinated contrast media: a systematic review protocol

INTRODUCTION

Iodinated contrast media are commonly used in medical imaging and can cause hypersensitivity reactions, including rare but severe life-threatening reactions. Although several prophylactic approaches have been proposed for severe reactions, their effects remain unclear. Therefore, we aim to review systematically the preventive effects of pharmacologic and non-pharmacologic interventions and predictors of acute, hypersensitivity reactions.

METHODS AND ANALYSIS

We will search the PubMed, EMBASE and Cochrane Central Register of Controlled Trials databases from 1 January 1990 through 31 December 2019 and will examine the bibliographies of eligible studies, pertinent review articles and clinical practice guidelines. We will include prospective and retrospective studies of any design that evaluated the effects of pharmacological and non-pharmacological preventive interventions for adverse reactions of non-ionic iodinated contrast media. Two assessors will independently extract the characteristics of the study and intervention and the quantitative results. Two independent reviewers will assess the risk of bias using standard design-specific validity assessment tools. The primary outcome will be reduction in acute contrast media-induced hypersensitivity reactions. The secondary outcomes will include characteristics associated with the development of contrast media-induced acute hypersensitivity reactions, and adverse events associated with specific preventive interventions. Unique premedication regimens (eg, dose, drug and duration) and non-pharmacological strategies will be analysed separately. Average-risk and high-risk patients will be considered separately. A meta-analysis will be performed if appropriate.

ETHICS AND DISSEMINATION

Ethics approval is not applicable, as this will be a secondary analysis of publicly available data. The results of the analysis will be submitted for publication in a peer reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42019134003.

Abstract 179: Significant Efficacy of Adenosine A3 Receptor Agonist AST-004 in Rat and Non-human Primate Models of Transient Middle Cerebral Artery Occlusion

Acute Ischemic Stroke (AIS) is the second-leading cause of global mortality with an estimated 6.7 million victims dying each year. Our research has focused on a non-neuronal cell type, the astrocyte, and has demonstrated that GPCR receptor-mediated maintenance of astrocyte function enhances critical homeostatic mechanisms in the brain including protection against AIS-associated edema, glutamate excitotoxicity and oxidative stress. AST-004 is a small-molecule agonist of the GPCR Adenosine A3 receptor (ADORA3), demonstrating excellent pharmacokinetics and blood-brain barrier permeability in preclinical species. The efficacy and dose-response of AST-004 was assessed in rat and non-human primate stroke models of transient occlusion of the middle cerebral artery (tMCAO). In rats, a 1.5-hour tMCAO was conducted with a 24-hour steady-state intravenous infusion of vehicle or AST-004 initiated at time of reperfusion (vehicle or three AST-004 dose levels, n=12/group); neurological deficit and stroke lesion volume (TTC staining/image analysis) were assessed 24 hours post-reperfusion. Compared to vehicle, AST-004 reduced brain lesion volume by 50% (p=0.04) and improved neurological function by 36% (p=0.03). In non-human primates (cynomolgus macaque), a 4-hour tMCAO was conducted with a 22-hour steady-state intravenous infusion initiated 2 hours prior to reperfusion (vehicle or three AST-004 dose levels, n=4/group). Stroke lesion, perfusion deficits and penumbral endpoints were assessed by FLAIR, T2, MRA, DWI and ASL at multiple timepoints out to 5 days post-occlusion. Neurological deficit was assessed at 5-days post-occlusion. AST-004 treatment resulted in statistically significant improvements in outcome relative to vehicle, up to a 44% decrease in lesion volume (p=0.02) and a 72% decrease in percentage of lesion growth (p=0.0006) over the 5-day study period. AST-004 treatment during occlusion also reduced the slope of lesion evolution prior to reperfusion by 72% (p=0.05) relative to vehicle. Together, these studies indicate the potential of a non-neuronal approach to reducing stroke lesion damage via the ADORA3 receptor. AST-004 is a first-in-class candidate that warrants further evaluation in human clinical stroke trials.

Radiogenomic characterization of multifocal prostate cancer

126

Background: Up to 20% of patients with negative multiparametric magnetic resonance imaging (MRI) harbor Gleason score ≥7 prostate cancer (PCa). We sought to elucidate the molecular basis of and determine the prognostic significance of PCa visibility on MRI. Methods: We identified a retrospective cohort of patients who underwent MRI prior to prostatectomy with both MRI visible (PIRADS 3 – 5) and invisible PCa. MRI for each patient was re-reviewed and co-registered with whole-mount histopathology. DNA and RNA were co-isolated from all tumor foci pre-identified on FFPE specimens. High depth, targeted DNA and RNA next generation sequencing was performed to characterize the molecular profile of each tumor focus using the Oncomine Comprehensive Panel (DNA) and a custom targeted RNAseq panel assessing PCa relevant alterations. A multigene RNAseq model was developed and validated in two independent cohorts to predict MRI visible PCa and to determine the prognostic significance of MRI visibility. Results: A total of 26 primary tumor foci from 10 patients were analyzed. Of the 14 (54%) invisible lesions on MRI, 5 (36%) were Gleason 3+4 = 7 and the remainder were Gleason 6. We detected high-confidence prioritized PCa relevant mutations in 54% (14/26) of tumor foci, 43% (6/14) of which were in MRI invisible lesions. Notable point mutations were in APC, AR, ARID1B, ATM, ATRX, BRCA2, FAT1, MAP3K1, NF1, SPEN, SPOP, and TP53. A 9-gene RNA signature, the majority of which were under-expressed cellular organization and structure genes, was developed to predict MRI visibility with an AUC of 0.89. Validation of this signature in an independent data set (n = 16) yielded an AUC of 0.88 with a specificity of 100% for predicting MRI visible tumors. Using this signature in a cohort of 375 patients with clinical follow up, we found that predicted MRI visibility status was not an independent predictor of biochemical recurrence, metastasis-free survival, or PCa specific mortality (all p > 0.05). Conclusions: We observed under-expression of cellular organization and structural genes in MRI visible tumors compared to MRI invisible cancer foci. Using our validated signature to predict MRI visibility status, we found that MRI visibility is not a significant predictor of oncological outcomes.

Integrative molecular profiling challenges robustness of prognostic signature scores in multifocal prostate cancer

96

Background: Tissue based biomarkers are increasingly utilized in men diagnosed with low grade prostate cancer (PCa) to guide definitive management vs. active surveillance. PCa is uniquely multifocal, suggesting ideal prognostic biomarkers should be robust to both undersampling of a high grade component of a mixed-grade tumor focus, as well as unsampled multifocal high grade tumor foci. Methods: To assess the robustness of prognostic biomarkers to multifocality, we designed a comprehensive multiplexed targeted RNA sequencing assay (mxRNAseq) capable of assessing multiple classes of transcriptional alterations and deriving available prognostic signature scores (e.g. Prolaris CCP and OncotypeDX GPS). We applied this assay to a retrospective cohort of 176 FFPE tissue samples representing the range of PCa progression. Single candidate biomarkers and derived prognostic signatures were analyzed in multifocal cases with only low-grade disease as well as those with extreme grade differences across tumor foci. Results: Our mxRNAseq assay robustly detected known coding gene/lncRNA expression, gene fusions, splice variants, and expressed somatic and germline mutations. Supervised clustering of target gene expression confirmed expected transcriptional module deregulation and derived prognostic signatures across PCa progression. Prognostic biomarkers (including derived signatures) showed no significant expression differences between low grade foci from prostates with and without high grade disease foci and were uniformly higher in high vs. low grade foci from the same case. In four cases of extreme multifocality (Gleason score 6 vs. ≥ 8 foci), prognostic signatures were significantly lower in low vs. high grade foci. In a clinical prostatectomy cohort of 1,418 men with diagnostic biopsy Gleason score 3+3 = 6 or 3+4 = 7, 21 (1.5%) had Gleason score ≥ 4+4 = 8, suggesting the initial biopsy missed or undersampled the most clinically relevant focus. Conclusions: Using a novel comprehensive mxRNAseq assay, our results challenge the robustness of prognostic biomarkers between multifocal low and high grade PCa foci, critically important in the context of un/under-sampled aggressive tumor foci.

Gastric endoscopic submucosal dissection as a treatment for early neoplasia and for accurate staging of early cancers in a United Kingdom Caucasian population

AIM

To investigate the efficacy of endoscopic submucosal dissection (ESD) at diagnosing and treating superficial neoplastic lesions of the stomach in a United Kingdom Caucasian population.

METHODS

Data of patients treated with or considered for ESD at a tertiary referral center in the United Kingdom were retrieved for a period of 2 years (May 2015 to June 2017) from the electronic patient records of the hospital. Only Caucasian patients were included. Primary outcomes were curative resection (CR) and were defined as ESD resections with clear horizontal and vertical margin and an absence of lympho-vascular invasion, poor differentiation and submucosal involvement on histological evaluation of the resected specimen. Secondary end-points were reversal of dysplasia at 12 mo endoscopic follow-up and/or at the latest follow up. Change in histological diagnosis pre and post ESD was also analysed.

RESULTS

Twenty-four patients were initially identified with intention to treat. 19 patients were eligible after mapping gastroscopy and ESD was attempted on a total of 25 ESD lesions, 4 of which failed and had to be aborted mid-procedure. Out of 21 ESD performed, en-bloc resection was achieved in 71.4% of cases. Resection was considered complete on endoscopy in 90.5% of cases compared to only 38.1% on histology. A total of 6 resections were considered curative (28%), 5 non-curative (24%) and 10 indefinite for CR or non-CR (24%). ESD changed the histological diagnosis in 66.6% of cases post ESD. Endoscopic follow-up in the “indefinite” group and CR group showed that 50% and 80% of patients were clear of dysplasia at the latest follow-up respectively; 2 cases of recurrence were observed in the “indefinite”group. Survival rate for the entire cohort was 91.7%.

CONCLUSION

This study provides early evidence for the efficacy of ESD as a therapeutic and diagnostic intervention in Caucasian populations and supports its application in the United Kingdom.

Congenital vascular anomalies of the liver

Congenital vascular anomalies of the liver include a range of malformations of the portal venous, hepatic arterial and venous systems. Congenital portosystemic shunts and arteriovenous malformations make up the two most frequent such malformations. While infantile haemangiomas of the liver, endothelial tumours characterised by vascular proliferation should also be considered, as a proportion of them form prenatally. Evidence to support treatment strategies for these infants and children has been mainly based on small case series. In this review, we explore classification, clinical presentation, investigation and treatment strategies.

Central Vein Preservation in Critical Venous Access

Introduction The lack of suitable veins in children with critical central venous access requirements is a major obstacle to optimal care and is potentially life-threatening. We present outcomes following the use of vein-preserving (VP) surgical techniques, notably the sheath exchange for tunneled lines (SETL). Materials and Methods A retrospective, single observer analysis of a prospectively maintained departmental logbook as well as the medical records of patients. Two broad groups of central line replacements were identified; those inserted following removal of a previous line and a traditional "plastic-free" (PF) period and those exchanged without such an interval. Results Overall, 19 lines were directly exchanged during the study period and compared with 34 inserted after a PF period. Similar catheter life spans and infection rates were demonstrated in each group; 125 (range, 78-173) days in VP exchanges versus 122 (range, 70-175) days in PF replacements (p = 0.41). Line Sepsis resulting in removal or change of line occurred at 103 (range, 60-147) days in VP group versus 104 (range, 45-164) days in PF (p = 0.73). Conclusion For children with critical venous access requirements, direct line exchange procedures are a robust and reproducible means of vein preservation. The outcomes compare favorably with those following the more traditional removal, a PF period and reinsertion.

Inter-radiologist agreement for CT scoring of pediatric splenic injuries and effect on an established clinical practice guideline

BACKGROUND

The American Pediatric Surgical Association (APSA) advocates for the use of a clinical practice guideline to direct management of hemodynamically stable pediatric spleen injuries. The clinical practice guideline is based on the CT score of the spleen injury according to the American Association for the Surgery of Trauma (AAST) CT scoring system.

OBJECTIVE

To determine the potential effect of radiologist agreement for CT scoring of pediatric spleen injuries on an established APSA clinical practice guideline.

MATERIALS AND METHODS

We retrospectively analyzed blunt splenic injuries occurring in children from January 2007 to January 2012 at a single level 1 trauma center (n = 90). Abdominal CT exams performed at clinical presentation were reviewed by four radiologists who documented the following: (1) splenic injury grade (AAST system), (2) arterial extravasation and (3) pseudoaneurysm. Inter-rater agreement for AAST injury grade was assessed using the multi-rater Fleiss kappa and Kendall coefficient of concordance. Inter-rater agreement was assessed using weighted (AAST injury grade) or prevalence-adjusted bias-adjusted (binary measures) kappa statistics; 95% confidence intervals were calculated. We evaluated the hypothetical effect of radiologist disagreement on an established APSA clinical practice guideline.

RESULTS

Inter-rater agreement was good for absolute AAST injury grade (kappa: 0.64 [0.59–0.69]) and excellent for relative AAST injury grade (Kendall w: 0.90). All radiologists agreed on the AAST grade in 52% of cases. Based on an established clinical practice guideline, radiologist disagreement could have changed the decision for intensive care management in 11% (10/90) of children, changed the length of hospital stay in 44% (40/90), and changed the time to return to normal activity in 44% (40/90).

CONCLUSION

Radiologist agreement when assigning splenic AAST injury grades is less than perfect, and disagreements have the potential to change management in a substantial number of pediatric patients.

Fabrication of 3-dimensional multicellular microvascular structures

Despite current advances in engineering blood vessels over 1 mm in diameter and the existing wealth of knowledge regarding capillary bed formation, studies for the development of microvasculature, the connecting bridge between them, have been extremely limited so far. Here, we evaluate the use of 3-dimensional (3D) microfibers fabricated by hydrogel electrospinning as templates for microvascular structure formation. We hypothesize that 3D microfibers improve extracellular matrix (ECM) deposition from vascular cells, enabling the formation of freestanding luminal multicellular microvasculature. Compared to 2-dimensional cultures, we demonstrate with confocal microscopy and RT-PCR that fibrin microfibers induce an increased ECM protein deposition by vascular cells, specifically endothelial colony-forming cells, pericytes, and vascular smooth muscle cells. These ECM proteins comprise different layers of the vascular wall including collagen types I, III, and IV, as well as elastin, fibronectin, and laminin. We further demonstrate the achievement of multicellular microvascular structures with an organized endothelium and a robust multicellular perivascular tunica media. This, along with the increased ECM deposition, allowed for the creation of self-supporting multilayered microvasculature with a distinct circular lumen following fibrin microfiber core removal. This approach presents an advancement toward the development of human microvasculature for basic and translational studies.

Controversies in choledochal malformation

Choledochal malformations (some of which are choledochal cysts) may be characterised as an abnormal dilatation of the biliary tract in the absence of acute obstruction. Most appear to be of congenital origin, probably related to distal bile duct stenosis, and almost 15% can now be detected antenatally. Excision and biliary reconstruction using a Roux loop as an open operation is still the standard to compare against, although laparoscopic reconstruction is increasingly reported. This article discusses recent advances in the understanding of choledochal malformation aetiology and classification, together with the role of newer modalites of surgical treatment such as laparoscopic excision and biliary reconstruction. Although these are definitely feasible, care should be taken before dispensing with standard open techniques that have minimal complications and proven long-term benefit.

Search for solar axions by the CERN axion solar telescope with 3He buffer gas: closing the hot dark matter gap

The CERN Axion Solar Telescope has finished its search for solar axions with (3)He buffer gas, covering the search range 0.64 eV ≲ ma ≲ 1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of gaγ ≲ 3.3 × 10(-10)  GeV(-1) at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of gaγ, for example by the currently discussed next generation helioscope International AXion Observatory.

IL-22-producing CD4+ cells are depleted in actively inflamed colitis tissue

T helper type (Th17) cytokines such as interleukin (IL)-17A and IL-22 are important in maintaining mucosal barrier function and may be important in the pathogenesis of inflammatory bowel diseases (IBDs). Here, we analyzed cells from the colon of IBD patients and show that Crohn's disease (CD) patients had significantly elevated numbers of IL-17+, CD4+ cells compared with healthy controls and ulcerative colitis (UC) patients, but these numbers did not vary based on the inflammatory status of the mucosa. By contrast, UC patients had significantly reduced numbers of IL-22+ cells in actively inflamed tissues compared with both normal tissue and healthy controls. There was a selective increase in mono-IL-17-producing cells from the mucosa of UC patients with active inflammation together with increased expression of transforming growth factor (TGF)-β and c-Maf. Increasing concentrations of TGF-β in lamina propria mononuclear cell cultures significantly depleted Th22 cells, whereas anti-TGF-β antibodies increased IL-22 production. When mucosal microbiota was examined, depletion of Th22 cells in actively inflamed tissue was associated with reduced populations of Clostridiales and increased populations of Proteobacteria. These results suggest that increased TGF-β during active inflammation in UC may lead to the loss of Th22 cells in the human intestinal mucosa.

A novel in vitro model for microvasculature reveals regulation of circumferential ECM organization by curvature

In microvascular vessels, endothelial cells are aligned longitudinally whereas several components of the extracellular matrix (ECM) are organized circumferentially. While current three-dimensional (3D) in vitro models for microvasculature have allowed the study of ECM-regulated tubulogenesis, they have limited control over topographical cues presented by the ECM and impart a barrier for the high-resolution and dynamic study of multicellular and extracellular organization. Here we exploit a 3D fibrin microfiber scaffold to develop a novel in vitro model of the microvasculature that recapitulates endothelial alignment and ECM deposition in a setting that also allows the sequential co-culture of mural cells. We show that the microfibers' nanotopography induces longitudinal adhesion and alignment of endothelial colony-forming cells (ECFCs), and that these deposit circumferentially organized ECM. We found that ECM wrapping on the microfibers is independent of ECFCs' actin and microtubule organization, but it is dependent on the curvature of the microfiber. Microfibers with smaller diameters (100–400 µm) guided circumferential ECM deposition, whereas microfibers with larger diameters (450 µm) failed to support wrapping ECM. Finally, we demonstrate that vascular smooth muscle cells attached on ECFC-seeded microfibers, depositing collagen I and elastin. Collectively, we establish a novel in vitro model for the sequential control and study of microvasculature development and reveal the unprecedented role of the endothelium in organized ECM deposition regulated by the microfiber curvature.

Challenges in accurate registration of 3-D medical imaging and histopathology in primary prostate cancer

Due to poor correlation between slice thickness and orientation, verification of medical imaging results by histology is difficult. Often validation of imaging findings of lesions suspicious for prostate cancer is driven by a subjective, visual approach to correlate in vivo images with histopathology. We describe fallacious assumptions in the correlation of imaging findings with pathology and identify the lack of accurate registration as a major obstacle in the validation of PET and PET/CT imaging in primary prostate cancer. Specific registration techniques that facilitate the most difficult part of the registration process--the mapping of pathology onto high-resolution imaging, preferably aided by the ex vivo prostate specimen--are discussed.

The role of pore geometry in single nanoparticle detection

We observe single nanoparticle translocation events via resistive pulse sensing using silicon nitride pores described by a range of lengths and diameters. Pores are prepared by focused ion beam milling in 50 nm-, 100 nm-, and 500 nm-thick silicon nitride membranes with diameters fabricated to accommodate spherical silica nanoparticles with sizes chosen to mimic that of virus particles. In this manner, we are able to characterize the role of pore geometry in three key components of the detection scheme, namely, event magnitude, event duration, and event frequency. We find that the electric field created by the applied voltage and the pore's geometry is a critical factor. We develop approximations to describe this field, which are verified with computer simulations, and interactions between particles and this field. In so doing, we formulate what we believe to be the first approximation for the magnitude of ionic current blockage that explicitly addresses the invariance of access resistance of solid-state pores during particle translocation. These approximations also provide a suitable foundation for estimating the zeta potential of the particles and/or pore surface when studied in conjunction with event durations. We also verify that translocation achieved by electro-osmostic transport is an effective means of slowing translocation velocities of highly charged particles without compromising particle capture rate as compared to more traditional approaches based on electrophoretic transport.