Towards a standardized framework for AI-assisted, image-based monitoring of nocturnal insects

Automated sensors have potential to standardize and expand the monitoring of insects across the globe. As one of the most scalable and fastest developing sensor technologies, we describe a framework for automated, image-based monitoring of nocturnal insects-from sensor development and field deployment to workflows for data processing and publishing. Sensors comprise a light to attract insects, a camera for collecting images and a computer for scheduling, data storage and processing. Metadata is important to describe sampling schedules that balance the capture of relevant ecological information against power and data storage limitations. Large data volumes of images from automated systems necessitate scalable and effective data processing. We describe computer vision approaches for the detection, tracking and classification of insects, including models built from existing aggregations of labelled insect images. Data from automated camera systems necessitate approaches that account for inherent biases. We advocate models that explicitly correct for bias in species occurrence or abundance estimates resulting from the imperfect detection of species or individuals present during sampling occasions. We propose ten priorities towards a step-change in automated monitoring of nocturnal insects, a vital task in the face of rapid biodiversity loss from global threats. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'.

POS0145 CLINICAL RESPONSE TO RITUXIMAB IS ASSOCIATED WITH PREVENTION OF B-CELL DRIVEN SALIVARY GLAND INFLAMMATION AND EPITHELIAL RESTORATION AS REVEALED BY MOLECULAR PATHOLOGY: RESULTS FROM THE TRACTISS TRIAL IN PRIMARY SJOGREN’S SYNDROME

Background

The TRial for Anti-B-Cell Therapy In patients with pSS (TRACTISS) is the largest multi-centre, placebo-controlled, phase-III trial with the administration of 2 cycles of Rituximab (RTX) or placebo at week 0 and 24, with trial clinical endpoints at week 48. Despite the primary endpoints (30% reduction in fatigue or oral dryness) were not met, RTX treated patients showed an improvement in secondary endpoints, such as unstimulated whole salivary flow (UWSF), and salivary gland (SG) total ultrasound score1,2. Additionally, recent post-hoc analysis of TRACTISS using novel CRESS composite endpoints3, highlighted a significantly increased response rate in the RTX vs placebo arm.

Objectives

To perform the first longitudinal analysis of matched transcriptomic and histological data of SG biopsies of pSS patients treated with RTX vs placebo at 3 time points, over 48 weeks, from the TRACTISS cohort, in order to identify mechanisms of response/resistance to B cell depletion.

Methods

29 pSS patients randomised to RTX or placebo arm consented for labial SG biopsies at week 0, 16 and 48. Patients received two 1000mg cycles of RTX or placebo at week 0 and 24. SG focus score, inflammatory aggregate area fraction, B-cells (CD20+), T-cells (CD3+), follicular dendritic cells (FDCs) (CD21+) and plasma cells (CD138+) density were assessed using quantitative digital image analysis. RNA sequencing with deconvolution and pathway analysis was performed to identify genes signatures and consensus gene modules as biomarkers of disease evolution and response/resistance to therapy.

Results

Placebo-treated SGs showed worsening of SG inflammation highlighted by the increment of aggregate size, B-cell density, development of new FDC networks, and a higher ectopic GC prevalence over 48 weeks, compared to RTX-treated patients. No difference in focus score, total T-cell and plasma cell infiltration was observed. RTX downregulated genes involved in immune cell recruitment and inflammatory aggregate organisation (e.g. CXCL13, CCR7 and PDCD1). Gene signature-based analysis of 35 immune cell types using XCell highlighted how RTX blocked class-switched and memory-B-cells accumulation in SGs over 48 weeks. Pathway analyses confirmed the downregulation of leukocyte migration, MHC-II antigen presentation, and T-cell co-stimulation immunological pathways, such as the CD40 receptor complex pathway. Among RTX-treated patients, only CRESS-responders demonstrated prevention of worsening B cell-driven molecular pathology signatures over time and a significant improvement in UWSF, in parallel with the upregulation of molecular pathways associated to SG restoration of the glandular epithelium. None of the above effects were observed at week 16 after the first RTX cycle.

Conclusion

Two RTX infusions repeated at week 24 exerted beneficial effects on labial SG inflammatory infiltration in pSS by downregulating genes involved in immune cell recruitment, activation and organisation in ectopic GCs. Conversely, all the above parameters showed significant evolution in placebo treated patients over 48 weeks demonstrating progression of SG immunopathology. Clinical responders to RTX based on CRESS response criteria were characterised by preservation of exocrine function which appear driven by SG epithelial restoration.

References

[1]Fisher, B. A. et al. Effect of rituximab on a salivary gland ultrasound score in primary Sjögren’s syndrome: results of the TRACTISS randomised double-blind multicentre substudy. Ann. Rheum. Dis.77, 412–416 (2018).

[2]Bowman, S. J. et al. Randomized Controlled Trial of Rituximab and Cost-Effectiveness Analysis in Treating Fatigue and Oral Dryness in Primary Sjögren’s Syndrome. Arthritis Rheumatol.69, 1440–1450 (2017).

[3]Arends, S. et al. Composite of Relevant Endpoints for Sjögren’s Syndrome (CRESS): development and validation of a novel outcome measure. Lancet Rheumatol.3, e553–e562 (2021).

Disclosure of Interests

None declared

OP0085 CELL LINEAGE-SPECIFIC TRANSCRIPT DECONVOLUTION OF SYNOVIAL BIOPSIES FROM THE R4RA TRIAL IDENTIFIES CELL POPULATIONS ASSOCIATED WITH RESPONSE TO RITUXIMAB AND TOCILIZUMAB

Background

The R4RA trial, the first biopsy-based randomised trial in TNF-i inadequate responder patients with Rheumatoid Arthritis, showed that molecular stratification of RA synovial tissue was associated with clinical response, demonstrating that, in patients with low/absent B-cell lineage signature in synovial-tissue, tocilizumab is superior to rituximab1.

Objectives

Here, we aimed to perform cell-transcript deconvolution of pre-and post-treatment synovial biopsies from the R4RA trial.

Methods

A total of 164 patients underwent pre-treatment synovial biopsy (US-guided or arthroscopic) prior to randomization 1:1 to rituximab (83) or tocilizumab (81). 65 patients had a repeat biopsy at 16 weeks when clinical response was assessed using Clinical Disease Activity Index (CDAI) 50% improvement. RNA extracted from a minimum of 6 synovial samples/patient underwent RNA-sequencing and the abundance of tissue-infiltrating immune and stromal cell populations was estimated using the Microenvironment Cell Populations-counter (MCP-counter) method (Figure 1a).

Results

At baseline, while synovial semiquantitative immunohistochemistry scores did not differ between CDAI50% responders and non-responders, both for rituximab and tocilizumab, MCP-counter analysis showed significantly higher CD8 T-cells in responders to rituximab and higher macrophage-monocytes and myeloid dendritic cells (mDC) in responders to tocilizumab (Figure 1b). Moreover, when patients were classified according to MCP-counter scores, B-cell poor patients (MCP-counter B cell score <median value) showed significantly higher response rates to tocilizumab, while no difference was found in B-cell rich patients (Figure 1c). In contrast, macrophage and myeloid dendritic cell (mDC) rich individuals showed higher responses to tocilizumab (Figure 1d). Combined scores for lymphoid and myeloid cells demonstrated that patients poor in B-cells but rich in macrophages/mDC had a significantly higher response to tocilizumab (77% responders to tocilizumab vs 14% responders to rituximab, p=0.017, OR 16.48, 95%CI 1.29-1000.5) (Figure 1e). By analysing disease activity over time from baseline to week 16, we found a statistically significant interaction effect between treatments and time in B-cell poor (p=0.003), T-cell poor (p=0.022), mDC rich (p=0.029) and B-cell poor/Macrophages-mDC rich patients (p=0.006) (Figure 1f-g-h). Finally, by applying MCP-counter on matched pre-and post-treatment biopsies, rituximab-treated patients showed a significant reduction of B-cells, T-cells and monocyte/macrophages, while tocilizumab-treated patients showed a significant reduction of monocyte/macrophages, T-cells, but also neutrophils, myeloid dendritic cells and, interestingly, an increase in fibroblast signature (Figure 1i).

Conclusion

In silico deconvolution of the synovial tissue identify pre-treatment lymphoid cell lineages associated with response to rituximab and myeloid cells for tocilizumab. The longitudinal analysis of matched pre- and post-treatment synovial biopsies indicated that both medications have an effect on synovial immune cells, but tocilizumab can also affect stromal cells.

References

[1]Humby et al. Rituximab versus tocilizumab in anti-TNF inadequate responder patients with rheumatoid arthritis (R4RA): 16-week outcomes of a stratified, biopsy-driven, multicentre, open-label, phase 4 randomised controlled trial Lancet. 2021 Jan 23;397(10271):305-317. doi: 10.1016/S0140-6736(20)32341-2.

Acknowledgements

We would like to thank all patients and the R4RA recruiting centres and principal investigators http://www.r4ra-nihr.whri.qmul.ac.uk/recruiting_centres.php We would also like to acknowledge the UK National Institute of Health Research for funding the R4RA trial (grant reference: 11/100/76) and Versus Arthritis for providing infrastructure support through the Experimental Arthritis Treatment Centre (grant number: 20022).

Disclosure of Interests

None declared.

OP0077 SYNOVIAL RNA-SEQ ANALYSIS OF THE R4RA TRIAL IDENTIFIES SIGNATURES OF TREATMENT RESISTANCE AND REFRACTORY STATE IN RHEUMATOID ARTHRITIS

Background

Although up to 5-20% of rheumatoid arthritis (RA) patients do not respond to all current medications including biologic therapies, relatively little is known about the underlying pathogenic mechanisms driving non-response. In the first biopsy-driven randomized clinical trial in RA (R4RA)1, patients, in whom synthetic-DMARDs and at least one anti-TNF drug were not effective, were randomised 1:1 to rituximab (RTX) or tocilizumab (TOC) with a balanced stratification based on their synovial B-cell rich/poor signature, and response was assessed at 16 weeks. Non-responders were subsequently allowed to switch to the alternative drug with 48-week follow-up.

Objectives

Investigate mechanisms of response and non-response to RTX and TOC through deep molecular (RNA-Sequencing) profiling of synovial tissue.

Methods

RNA-Seq from baseline synovial tissue biopsies of patients who received RTX (n=88) or TOC (n=94) at any point in the trial was analysed for differentially expressed genes and associated modules between responders and non-responders. Response was defined as 50% improvement in clinical disease activity index (CDAI) score. Patients who had received both drugs during the trial were subdivided into RTX only responders (pro-RTX, n=9), TOC only responders (pro-TOC, n=12) and refractory patients (no response to both RTX & TOC, n=32) and analysed for differential gene expression and performed gene module analysis.

Results

6625 genes were significantly differentially expressed between RTX responders compared to non-responders, with a predominance of antigen presentation as well as T- and B-cell genes being associated with response, while non-response was linked to fibroblast associated genes. Comparison between TOC responders and non-responders identified fewer (85) differentially expressed genes, however lymphocyte and immunoglobulin genes were also high in the synovial tissue of TOC responders similar to RTX responders, while non-responder genes and modules also included a fibroblast signature.

The cross-over study design enabled comparison of rituximab-specific responders (pro-RTX), tocilizumab-specific responders (pro-TOC) and refractory patients (non-responders to both RTX & TOC, n=32) in a 3-way analysis (see Figure 1). This identified 1980 genes upregulated both in pro-RTX and pro-TOC patients, 175 genes exclusive to the pro-RTX group and 306 to the pro-TOC group, while 1277 genes were exclusive to the refractory group. While leukocyte modules and genes dominated RTX & TOC response, the refractory state was strongly associated with fibroblast genes and modules. We confirmed the observed expansion of fibroblasts from the RNA-Seq data by immunohistochemistry showing the presence of DKK3+ sublining fibroblasts in refractory rather than responder patients.

Conclusion

We provide novel insights into the cellular and molecular pathways underpinning multi-biologic resistance that define a refractory RA phenotype, characterised by a stromal/fibroblast signature.

References

[1]Humby, F., et al. Lancet (2021)

Acknowledgements

We would like to thank all patients and the R4RA recruiting centres and principal investigators http://www.r4ra-nihr.whri.qmul.ac.uk/recruiting_centres.php We would also like to acknowledge the UK National Institute of Health Research for funding the R4RA trial (grant reference: 11/100/76) and Versus Arthritis for providing infrastructure support through the Experimental Arthritis Treatment Centre (grant number: 20022).

Disclosure of Interests

None declared.

POS0441 IN-DEPTH ANALYSIS OF Axl AND MerTK EXPRESSION PATTERNS AND REGULATION BY BIOLOGIC TREATMENTS IN RHEUMATOID ARTHRITIS

Background

Tyrosine kinases receptors MerTK and Axl have been implicated in the pathogenesis of several autoimmune diseases. Despite sharing significant structural homology and having common ligands, Axl and MerTK have distinct features and biological functions [1]. A growing body of evidence suggests that both Axl and MerTK play a crucial role in Rheumatoid Arthritis (RA) pathogenesis and progression and may be exploited as novel therapeutic targets [2]. However, numerous unanswered questions remain to be addressed.

Objectives:

i.To define common and distinct gene-partners of Axl/MerTK and quantify their expression in RA synovial tissue.

ii.To assess the co-expression of Axl/MerTK by synovial cells.

iii.To outline the longitudinal variation in Axl/MerTK expression upon treatment intervention.

Methods

Synovial tissue samples were collected by US-guided synovial biopsy from: i. Patients with early (<12 months) RA DMARDs/steroid-naïve [n=87]; and ii. RA patients who failed the first-line biologic with TNF-inhibitors (TNFi) before and 16 weeks after receiving either Rituximab (RTX) or Tocilizumab (TOC) [n=164] [3]. Gene expression was obtained by bulk RNAseq performed on an Illumina HiSeq2500 platform. Axl-/MerTK-modules were defined using STRING networks and the module expression determined by the mean z-score of regularized log transformed expression for all genes in the set. Axl, MerTK, CD55, CD90, CD68 protein expression was analysed by multiplex immunofluorescence staining.

Results

Using STRING network analysis, we defined an Axl- and a MerTK-module composed of 31 predicted gene-partners of either Axl or MerTK. Thirteen genes were common to both modules and included the ligands Gas6 and ProteinS, and EGFR. Conversely, eighteen genes were uniquely present in the Axl-module (e.g., PIK3-family, IGF1R, IFNAR1 and STAT3) or the MerTK-module (e.g., Galectin3 and TULP, recently discovered MerTK ligands, FCGR1A/CD64, PTPN1and MEGF10). Axl/MerTK-modules quantified in the early-arthritis treatment-naïve RNAseq dataset showed a significant negative correlation with the synovitis score (Axl r=−0.33, p=0.0032; MerTK r=-0.33, p=0.003). At protein level, CD68+macrophages of the Lining showed notable heterogeneity between patients: they could express either Axl or MerTK alone, or co-express both. Axl was also present in most CD55+ Lining Fibroblast-Like-Cells (FLS) but not by CD90+ Sublining FLS while MerTK, as expected, was restricted to macrophages, including intra-aggregate tingible-body-macrophages.

To define how Axl and MerTK vary depending on disease stage and treatment exposure, we quantified their gene expression in active RA patients inadequately responding to TNFi, prior and 16 weeks after starting second-line biologic (RTX or TOC) [3]. Differently from the early-arthritis cohort, MerTK was significantly up-regulated in synovia characterised by higher degree of tissue inflammation (lympho-myeloid > diffuse-myeloid > pauci-immune, p<0.0001) and significantly positively correlated with several cytokines’ genes such as TNF, IL-6, CCL8 and IL-10. MerTK expression was dependent on clinical response to RTX but not TOC as assessed by EULAR response (DAS28CRP, good vs none/mod, FDRresp 0.048). Conversely, Axl expression significantly increased upon IL-6 blockade by TOC independently of the clinical response (FDRtime 0.016).

Conclusion

Our data further corroborate that Axl and MerTK constitute a dynamic axis influenced by the synovial tissue inflammatory features, the disease stage, the exposure and the response to targeted treatment and the blockade of critical inflammatory pathways over time. A better understanding of the individual features of these tyrosine kinases as well as their interaction would be beneficial to define novel treatment approaches.

References

[1]Zagórska A, et al. Nat Immunol. 2014 Oct;15(10):920-8

[2]Kemble S, Croft AP. Front Immunol. 2021 Sep 3;12:715894

[3]Humby F et al. Lancet. 2021 Jan 23;397(10271):305-317

Acknowledgements

Versus Arthritis.

Disclosure of Interests

None declared.

OP0109 EXPRESSION QUANTITATIVE TRAIT LOCI IN EARLY TREATMENT-NAÏVE RHEUMATOID ARTHRITIS

Background

To date more than 100 genetic loci have been associated with rheumatoid arthritis (RA), particularly in the human leukocyte antigen (HLA) region. Our understanding of the functional consequences of genetic variation in RA causality, however, is limited and it has been shown that a substantial portion of complex disease risk alleles modify gene expression in a cell-specific manner [1]. The Pathobiology of Early Arthritis Cohort (PEAC) is a longitudinal study looking at treatment-naiv̈e RA patients with genotyped data as well as both synovial and blood RNA-sequenced biopsies prior to treatment with disease modifying anti-rheumatic drugs (DMARDs).

Objectives

To explore expression quantitative trait loci (eQTL) in synovium and blood within PEAC and characterise the effects of genetic variation on gene expression measured by RNA-sequencing. A further goal was to investigate the role of these variants in RA disease severity and response variables.

Methods

Genotypes were generated by Illumina Human CoreExome-24 version 1-0 array in 118 RA patients. Single nucleotide polymorphisms (SNPs) in the HLA region were imputed using HLA-TAPAS. A candidate gene study was performed on variants within the HLA region using Plink v2.0. Synovial (n=85) and blood (n=51) RNA-sequenced samples then underwent cis-eQTL analysis (loci within ±5x105Mb of the variant) based on linear regression models with the matrixeQTL R package using PEER [2] and PCA eigenvectors as covariates. Differences in eQTL between tissues were determined using a linear interaction term.

Results

The candidate gene study determined several amino acids around HLA-DRB1 acting as markers for seropositivity, which replicated findings by Raychaudhuri et. al. [3]. Using eQTL analysis, around 33,000 synovial SNPs were found with genome-wide significance (p ≤ 5x10-8) and around 29,000 in blood. This corresponded to 279 unique significant genes in synovium and 417 in blood (Figure 1). There were 100 genes common to both synovium and blood, including PSORS1C3, HLA-DRB9 and ERAP2, which have known associations with autoimmune diseases and inflammatory arthritis. Notably, 92 genes showed significantly different patterns of QTL expression between synovial tissue and blood (p ≤ 5x10-8). eQTL data also confirmed the triad of genetic variants significantly driving tissue gene expression of HLA-DPB2, while both HLA-DPB2 SNPs and HLA-DPB2 RNA-sequencing synovial expression correlated highly with erythrocyte sedimentation rate (ESR).

Figure 1.

Manhattan plots for cis-expression quantitative trait loci (eQTL) analysis performed on 85 synovial samples (top) and 51 blood samples (middle). Tissue interaction eQTL (bottom) show significant differences between tissues (p ≤ 5x10-8).

Conclusion

The high significance of genes in the HLA region in both tissues is in-keeping with the strong association between HLA and susceptibility to RA, as well as other autoimmune diseases. Most notably variants linked to HLA-DPB2 synovial expression were found to be a marker for disease severity through ESR association. Additionally, the significant differences between eQTL in blood and synovium highlight the need to explore functional consequences of genetic associations in the diseased tissue directly.

References

[1]Thalayasingam et. al. (2018). CD4+ and B lymphocyte expression quantitative traits at rheumatoid arthritis risk loci in patients with untreated early arthritis: implications for causal gene identification. Arthritis & Rheumatology, 70(3), 361-370.

[2]Stegle et al. (2012). Using probabilistic estimation of expression residuals (PEER) to obtain increased power and interpretability of gene expression analyses. Nature protocols, 7(3), 500-507.

[3]Raychaudhuri et al. (2012). Five amino acids in three HLA proteins explain most of the association between MHC and seropositive rheumatoid arthritis. Nature genetics, 44(3), 291-296.

Disclosure of Interests

None declared

OP0136 RITUXIMAB PREVENTS THE PROGRESSION OF B-CELL DRIVEN INFLAMMATORY INFILTRATE IN THE MINOR SALIVARY GLANDS OF PRIMARY SJOGREN’S SYNDROME BY DOWNREGULATING IMMUNOLOGICAL PATHWAYS KEY IN ECTOPIC GERMINAL CENTRE ORGANIZATION: RESULTS FROM THE TRACTISS TRIAL

Background:

The pathogenic role of B-cells in primary Sjögren’s Syndrome (pSS) is well established and B cell abnormalities. Because of the substantial role of B-cells, rituximab (RTX), a chimeric anti-CD20 monoclonal antibody, has been considered as a potential biologic disease modifying drug to reduce disease activity in pSS. To date, the TRial for Anti-B-Cell Therapy In patients with pSS (TRACTISS) is the largest multi-centre, placebo-controlled trial with RTX. Despite the unmet primary endpoints (30% reduction in fatigue or oral dryness, measured by visual analogue scale), RTX treated patients showed an improvement in unstimulated whole salivary flow (Bowman et al. Arthritis Rheumatol 2017;69:1440–1450).

Objectives:

To provide the first longitudinal transcriptomic and histological analysis at 3 time points over 48 weeks of labial SGs of pSS patients treated with RTX, in comparison to placebo, from the TRACTISS cohort.

Methods:

26 pSS patients randomised to RTX or placebo arm consented for labial SG biopsies at baseline, weeks 16 and 48. Patients received two 1000mg cycles of RTX or placebo at baseline and week 24. SG focus score, inflammatory aggregate area fraction, B-cells (CD20+), T-cells (CD3+), follicular dendritic cells (FDCs) (CD21+) and plasma cells (CD138+) density were assessed by H&E and immunofluorescence staining. The histological analysis was performed by digital imaging using QuPath software. RNA was extracted from matched labial SG lobules and sequenced with Illumina platform. A Principal Component Analysis (PCA) and features driving the PCA were investigated along with the most influential gene loadings. The limma-voom R pipeline was used to extract Differential Expressed Genes (DEGs) between placebo and RTX group at week 48, and gene ontology (GO) enrichment analysis performed through EnrichR to derive GO terms and pathways associated with DEGs.

Results:

Placebo-treated labial SGs showed a worsening of inflammation highlighted by the increment of B-cell density, development of new FDC networks, and a higher ectopic GC prevalence at week 48, compared to RTX-treated patients. No difference in total T-cells and plasma cell infiltration was observed. RTX downregulated genes involved in immune cell recruitment and inflammatory aggregate organisation (e.g. CCR7, CCL19, CD52, and PDCD1) and gene signature-based analysis of 64 immune cell types highlighted how RTX preferentially blocked class-switched- and memory-B-cells infiltration in SGs at week 48. Pathway analyses confirmed the downregulation of leukocyte migration, MHC class II antigen presentation, and T-cell co-stimulation immunological pathways, such as the CD40 receptor complex pathway. The analysis of placebo SGs transcriptomic at week 48 showed a higher expression of genes linked to ectopic GC organisation, such as CXCL13, CCL19, LTβ, in female compared to male subjects. Gender was confirmed as a key co-variate responsible for most of the variation in the PCA, together with the SG focus score and the foci area fraction.

Conclusion:

Treatment with RTX showed beneficial effects on labial SG inflammatory infiltration in pSS, by downregulating genes involved in immune cell recruitment, activation and organisation in ectopic GCs. Class-switched-B-cells, memory-B-cells and FDC network development were primarily affected appearing to be responsible for the lack of progression in SG B cell infiltration in the RTX compared to the placebo arm in which clear worsening of SG immunopathology over 48 weeks was detected in female patients. Although a clear association with the clinical improvement in unstimulated salivary flow observed at week 48 in RTX-treated patients could not be established given the low number of patients consenting to 3 longitudinal biopsies it is conceivable that RTX is responsible for preserving exocrine function.

Acknowledgements:

SJB receives a salary contribution from the NIHR Birmingham Biomedical Research Centre.

Disclosure of Interests:

Elena Pontarini: None declared, Farzana Chowdhury: None declared, Elisabetta Sciacca: None declared, Sofia Grigoriadou: None declared, Felice Rivellese: None declared, Davide Lucchesi: None declared, Katriona Goldmann: None declared, Liliane Fossati-Jimack: None declared, Paul Emery: None declared, Wan Fai Ng: None declared, Nurhan Sutcliffe: None declared, Colin Everett: None declared, Catherine Fernandez: None declared, Anwar Tappuni: None declared, Myles Lewis: None declared, Costantino Pitzalis: None declared, Simon J. Bowman Consultant of: SJB In 2020 I have received consultancy fees from Novartis, Abbvie and Galapagos., Michele Bombardieri: None declared

OP0011 INTEGRATION OF FLOW AND DIGITAL CYTOMETRY IN EARLY TREATMENT-NAÏVE RHEUMATOID ARTHRITIS IDENTIFIES DISTINCT IMMUNOPHENOTYPES IN PERIPHERAL BLOOD AND DISEASE TISSUE

Background:

The study of synovial tissue in patients with Rheumatoid Arthritis (RA) has led to the identification of synovial patterns of immune cell infiltration and specific cellular subsets associated that have been disease activity and clinical outcomes(1–3). However, the relationship of circulating and synovial immune cell sub-sets with histopathological features and clinical outcomes remains to be defined.

Objectives:

To assess the relationship of peripheral blood and synovial immune cells with RA histopathology and clinical outcomes, by performing flow and digital cytometry in matched peripheral blood and synovial samples from patients with early RA.

Methods:

70 patients with early (<12 months) untreated RA (2010 criteria) recruited in the pathobiology of early Arthritis Cohort (PEAC) at the Barts Health NHS Trust were included(1). Peripheral blood mononuclear cells (n=70) were analysed by flow cytometry. Matched synovial tissues (n=70) obtained by minimally invasive ultrasound-guided synovial biopsy underwent semi-quantitative scoring (0-4) of immune cell infiltration and classification into lympho-myeloid (LM), diffuse-myeloid (DM) and pauci-immune (PI) pathotypes, as previously described(1). 49 synovial and 36 matched peripheral blood samples underwent RNA-sequencing and were analysed by digital cytometry (Xcell) (4) and Singular Value Decomposition (SVD).

Results:

Circulating B cells and their subsets showed significant inverse correlations with inflammatory markers (ESR, CRP), disease activity (swollen joints, four components and two components(5) DAS28) and ultrasound scores (Fig 1A). Among T cell subsets, CXCR5-PD1hiICOS+CD4+ T cells (T peripheral helper cells, Tph) had strong positive correlations with inflammatory markers (ESR and CRP), disease activity (DAS28) and ultrasound scores (Fig 1B). Tph in the peripheral blood also correlated with immune cell infiltration in synovia (Fig 1C) and were significantly higher in patients with a LM pathotype (Fig 1D). Accordingly, circulating Tph were associated with synovial LM pathotype independently of clinical features such as DAS28, ACPA positivity, Body Mass Index (BMI) and age (AUC 0.821). By applying digital cytometry in matched synovial and peripheral blood samples, synovial B and T cells were significantly higher in patients with a LM pathotype, in line with the histological definition of the LM pathotype – rich in B and T cells. On the contrary, circulating B cells and total CD4 and CD8 T cells were significantly lower in patients with a synovial LM pathotype (Fig 1E). The Tph signature in synovia derived by Singular Value Decomposition (SVD) correlated with baseline ESR (R 0.38, p<0.0001) and DAS28 (R 0.35, p <0.0001) and with delta-DAS28 after 6 months of treatment with conventional synthetic DMARDs (R 0.27, p 0.026). Finally, the baseline synovial Tph signature was significantly higher in patients who progressed to the use of biologics and was predictive of future biologic DMARDs use, independently of baseline DAS28, ACPA positivity, BMI and age (AUC 0.703).

Conclusion:

By combining conventional flow cytometry in the peripheral blood and digital cytometry on matched synovial and peripheral blood samples, we highlight diverging associations of circulating immune cell subsets with synovial inflammation and pathotypes. Tph cells, in particular, emerge as predictors of lympho-myeloid synovial inflammation and disease progression.

References:

[1]F. Humby et al., Ann. Rheum. Dis. 78, 761–772 (2019), doi:10.1136/annrheumdis-2018-214539. [2]M. J. Lewis et al., Cell Rep. 28, 2455-2470.e5 (2019), doi:10.1016/j.celrep.2019.07.091.[3]D. a Rao et al., Nat. Publ. Gr. 542, 110–114 (2017), doi:10.1038/nature20810.[4]D. Aran et al., Genome Biol. 18, 220 (2017), doi:10.1186/s13059-017-1349-1.[5]E. M. A. Hensor et al., Rheumatology. 58, 1400–1409 (2019), doi:10.1093/rheumatology/kez049.

Figure 1.

Acknowledgements:

The Pathobiology of Early Arthritis Cohort (PEAC) was supported by the MRC (grant 36661). Versus Arthritis provided funding infrastructure support (grant 20022). F. Rivellese is funded by an NIHR Transitional Research Fellowship (TRF-2018-11-ST2-002). We would like to thank the patients and the clinical and laboratory team (core team) at Queen Mary University of London.

Disclosure of Interests:

None declared

Tracking Musical Voices in Bach's The Art of the Fugue: Timbral Heterogeneity Differentially Affects Younger Normal-Hearing Listeners and Older Hearing-Aid Users

Auditory scene analysis is an elementary aspect of music perception, yet only little research has scrutinized auditory scene analysis under realistic musical conditions with diverse samples of listeners. This study probed the ability of younger normal-hearing listeners and older hearing-aid users in tracking individual musical voices or lines in JS Bach's The Art of the Fugue. Five-second excerpts with homogeneous or heterogenous instrumentation of 2–4 musical voices were presented from spatially separated loudspeakers and preceded by a short cue for signaling the target voice. Listeners tracked the cued voice and detected whether an amplitude modulation was imposed on the cued voice or a distractor voice. Results indicated superior performance of young normal-hearing listeners compared to older hearing-aid users. Performance was generally better in conditions with fewer voices. For young normal-hearing listeners, there was interaction between the number of voices and the instrumentation: performance degraded less drastically with an increase in the number of voices for timbrally heterogeneous mixtures compared to homogeneous mixtures. Older hearing-aid users generally showed smaller effects of the number of voices and instrumentation, but no interaction between the two factors. Moreover, tracking performance of older hearing aid users did not differ when these participants did or did not wear hearing aids. These results shed light on the role of timbral differentiation in musical scene analysis and suggest reduced musical scene analysis abilities of older hearing-impaired listeners in a realistic musical scenario.

B Cell Synovitis and Clinical Phenotypes in Rheumatoid Arthritis: Relationship to Disease Stages and Drug Exposure

OBJECTIVE

To define the relationship of synovial B cells to clinical phenotypes at different stages of disease evolution and drug exposure in rheumatoid arthritis (RA).

METHODS

Synovial biopsy specimens and demographic and clinical data were collected from 2 RA cohorts (n = 329), one of patients with untreated early RA (n = 165) and one of patients with established RA with an inadequate response to tumor necrosis factor inhibitors (TNFi-IR; n = 164). Synovial tissue was subjected to hematoxylin and eosin and immunohistochemical staining and semiquantitative assessment for the degree of synovitis (on a scale of 0-9) and of CD20+ B cell infiltrate (on a scale of 0-4). B cell scores were validated by digital image analysis and B cell lineage-specific transcript analysis (RNA-Seq) in the early RA (n = 91) and TNFi-IR (n = 127) cohorts. Semiquantitative CD20 scores were used to classify patients as B cell rich (≥2) or B cell poor (<2).

RESULTS

Semiquantitative B cell scores correlated with digital image analysis quantitative measurements and B cell lineage-specific transcripts. B cell-rich synovitis was present in 35% of patients in the early RA cohort and 47.7% of patients in the TNFi-IR cohort (P = 0.025). B cell-rich patients showed higher levels of disease activity and seropositivity for rheumatoid factor and anti-citrullinated protein antibody in early RA but not in established RA, while significantly higher histologic synovitis scores in B cell-rich patients were demonstrated in both cohorts.

CONCLUSION

We describe a robust semiquantitative histologic B cell score that closely replicates the quantification of B cells by digital or molecular analyses. Our findings indicate an ongoing B cell-rich synovitis, which does not seem to be captured by standard clinimetric assessment, in a larger proportion of patients with established RA than early RA.

Identification of the novel HLA-C*07:315 allele

The HLA-C*07:315 allele is mostly identical to HLA-C*07:09 but has a non-synonymous substitution of C to G in exon 2.

[Removal of the laryngeal mask airway in the post-anesthesia care unit. A means of process optimization?]

BACKGROUND

Removal of the laryngeal mask airway in the post-anesthesia care unit could potentially contribute to a faster turnover from one operation to the next. The aim of this study was, therefore, to obtain an insight into the potential time saving and the safety of planned removal of the ProSeal™-LMA (PLMA) in the post-anesthesia care unit.

METHODS

In this study 120 adult patients with American Society of Anesthesiologists (ASA) classification I-II, age range 18-85 years, undergoing a surgical procedure under general anesthesia in which the PLMA was used were randomly assigned to one of two groups. In group I, the PLMA was removed in the awake patient in the operating room close to the end of the procedure. In group II, the anesthetised but spontaneously breathing patients were moved to the recovery room and the PLMA removed when the patient was awake. The anesthesia technique was standardized [balanced, sevoflurane, fentanyl, bispectral index-guided (BIS) target value=35±5] and identical in both groups until randomization. Patients were breathing room air during transport to the recovery room. Different time intervals as well as the incidence of critical incidents were compared between groups. An oxygen saturation (S(p)O(2)) value <95% was considered a clinically relevant and S(p)O(2) values <90% as clinically critical O(2)-desaturation.

RESULTS

Removal of the PLMA took place after an average of 4.9±5.1 min in group I and after 19.5±9.6 min in group II. There was no difference in the availability of the anesthetist in the operating room for the following procedure between groups (group I: 12±5.6 min vs. group II: 10.7±4.2 min, p>0.05) despite the fact that patients of group II left the operating room faster (4.9±3.9 min) than patients of group I (7.1±5.1 min, p<0.01). In group II patients were ready for discharge (White score=12) from the recovery room later (13.2±8.2 min) than in group I (3.6±4.8 min, p<0.01). There were no significant differences in other process related time intervals between group I and group II: duration of the operation (113.2±45.9 min vs. 105.3±42.6 min), duration of dressing (5.1±3.7 min vs. 4.6±2.8 min), duration of transport to the recovery room (3.9±1.3 min vs. 3.6±1.3 min) and information at end of surgery by the surgeon (22.5±9.3 min vs. 22.4±10.5 min). The incidence of clinically relevant as well as clinically critical O(2) desaturation at the time of recovery room arrival (S(p)O(2)≤90%) was increased in group II with 33.3% vs. 56.6% and 13.3% vs. 6.7%, p<0.01, respectively.

CONCLUSION

Planned PLMA removal in the recovery room after BIS-guided balanced anesthesia did not enable the anesthetist to be available earlier for induction of anesthesia in the following patient. Hence the anesthetist could not contribute to a faster turnover of cases. Obviously, with the type of close communication between surgeon and anesthetist dictated by the study protocol (announcement of expected end of surgery by the surgeon 20 min before end of surgery) it is possible for the patient to regain consciousness within a very small time window following the end of surgery. Following this kind of protocol, postponement of removal of the LMA in the recovery room does not seem to be attractive neither from a clinical nor an economic point of view. In contrast, removal of LMA in the recovery room should be restricted to occasional cases with an abrupt end of the operation or prolonged emergence from anesthesia. The obvious risk of hypoxemia necessitates continuous O(2) application and S(p)O(2) monitoring during transport to the recovery room.

[Clinical use of the ProSeal™ laryngeal mask in infants, children and adolescents : prospective observational survey]

BACKGROUND

In contrast to the adult population scientific data on ProSeal™-LMA (PLMA) usage in infants, children, and adolescents are rather limited. Most data have been generated by expert users in studies on small numbers of patients. The aim of this study was to gather comprehensive data about the characteristics, efficacy and safety of its routine use in children at a teaching institution.

METHODS

Using a standardized reporting form the following data were collected in the course of a prospective survey on PLMA usage in patients aged up to 18 years: user characteristics, patient characteristics, type and duration of operation, details of airway management and anesthetic technique, details of PLMA usage-related critical incidents and postoperative status of the patient.

RESULTS

Use of the PLMA was documented in 512 patients by 61 anesthesiologists (32% staff grade, 68% trainees). The average age, height and weight of the patients was 8 years (range 0-17 years), 130 cm (range 54-193 cm) and 29 kgBW (range 5-130 kgBW), respectively. Anesthesia was induced intravenously in 458 patients (89.5%) and by inhalation in 54 patients. Maintenance of anesthesia was by total intravenous anesthesia (propofol) in 184 patients (36.5%) and by an inhalational agent (sevoflurane or desflurane) in 320 patients (63.7%). Neuromuscular blocking agents were used in 7 patients (1.4%). The patients were anesthetized for an average of 80 min (range 15-270 min) and insertion success rate was 99% with a maximum of 3 attempts. The average initial airway leak pressure was 27cm H(2)O (range 12-40 cm H(2)O); however, lower pressures were recorded for smaller size masks (size 1.5-2.5) without a dorsal cuff than for larger size masks (size 3-5; p<0.01). Ventilation was controlled in 96% and combined with PEEP in 39% of cases. Critical incidents associated with PLMA were documented in a total of 8.4% of cases, the majority being minor trauma, evidenced by blood on the PLMA on removal, followed by some form of airway obstruction. In 3.3% of cases these incidents were judged as clinically relevant of which 0.6% were classified as serious. Twice as many problems occurred during induction of anesthesia as in the maintenance phase and emergence phase of anesthesia (p=0.037). In 1.6% the PLMA was abandoned in favor of the endotracheal tube. In 7 patients the PLMA was exchanged in the induction room whereas in 1 patient this took place intraoperatively. Failure of ProSeal™ laryngeal mask use correlated with the level of PLMA use experience with 75% of failures caused by users with an experience of less than 50 uses and no failure in users with an experience of more than 100 uses. Failure did not correlate with the size of the mask. In 2 cases the PLMA was successfully used after failed endotracheal intubation. In 6 patients drainage of regurgitated gastric fluid through the drain tube was documented. No long-term adverse sequelae resulted in any patient.

CONCLUSION

This survey demonstrates that the PLMA can be used effectively in infants, children and adolescents in the routine university clinical practice setting. However, this study does not confirm the extremely high success and low complication rates reported in controlled studies. The results support the assumption that with the PLMA regurgitated gastric fluid can be drained away from the larynx through the drain tube.

Leckagedruck der ProSeal®-Kehlkopfmaske

BACKGROUND

The ProSeal laryngeal mask airway (PLMA) has been studied in numerous investigations and the airway leak pressure (P(leak)) is often used as a primary end-point, particularly in comparative studies with other supraglottic airway devices. The PLMA offers the opportunity to place a gastric tube through the drain-tube and P(leak) measurement can take place both with and without a gastric tube. With this study we tested the hypothesis that the use of a gastric tube influences the P(leak).

METHODS

The P(leak) of the PLMA was studied in 98 patients under total intravenous anaesthesia with propofol (0.1-0.15 mg*kgBW-1*min-1) and remifentanil (0.1-0.3 microg*kgBW-1*min-1) before and after placement of a gastric tube through the drain-tube of the PLMA.

RESULTS

There was no significant difference between the mean baseline P(leak) without a gastric tube in place (25+/-6.3 cm H(2)O) and the mean P(leak) after placement of a gastric tube (25+/-6.7 cm H2O; p=0.6).

CONCLUSION

Placement of a gastric tube through the drain-tube of the PLMA does not influence the P(leak). Providing the same method of measurement has been used, P(leak) values from different studies obtained with or without a gastric tube in place are comparable.

[Anaesthesia education at german university hospitals: the teachers' perspective -- results of a nationwide survey]

AIM OF THIS STUDY

The principle purpose of this study was to collect data on the conditions and practice of anaesthesia education as well as the teaching qualification of consultants at German university hospitals. Based upon the collected data, areas of weakness and strength as well as measures required to improve anaesthesia training are described.

METHODS

A questionnaire containing 26 items was mailed to 607 consultants employed at 41 German university hospitals in June 2003.

RESULTS

A total of 255 questionnaires was analysed (response rate: 43 %). Genuine training activities account for 14 % of the working hours of the participating consultants. On average, at the institutions of participating consultants, novices work for a duration of 1 month together with a consultant anaesthetist before they give anaesthetics without direct and constant supervision. When asked to describe the predominant method of training at their institution 71 % indicated "case-oriented teaching"; however, 53 % chose "see one, do one, teach one" and 49 % "learning by doing" as method of training as well (multiple choice). According to 63 % of respondents, departmental educational activities usually happen after their regular working hours. "Daily workload" (96 %), "time pressure" (96 %), "lack of time" (96 %) and "lack of personnel" (90 %) were indicated as the main obstacles of teaching. According to 80 % of respondents, a dedicated financial budget for education does not exist; instead, financial resources of third parties (industry) (58 %), of the state (for research und undergraduate education) (60 %) and of patients service (66 %) are used to ensure training of anaesthesia residents.

CONCLUSION

Due to a lack of a dedicated financial budget for resident training and an increasing economic pressure, "lack of time" and "lack of personnel" are the main factors leading to the situation at German university hospitals that consultants can only spend 14 % of their working hours for teaching purposes despite of sufficient qualification and motivation. As a consequence, novice anaesthetists are faced with the situation to be working without direct and constant supervision after 1 month of training.

[Influence of neuromuscular blockade on the airway leak pressure of the ProSeal laryngeal mask airway]

BACKGROUND

The ProSeal laryngeal mask airway (PLMA) is increasingly used for surgical procedures that might require the intraoperative use of neuromuscular blocking agents. The airway seal of the PLMA depends on the interplay of the surrounding soft tissue of the neck and the cuff of the mask. An intraoperative neuromuscular blockade could lead to a decrease of the airway leak pressure (P (leak)) secondary to the relaxation of the muscles of the neck. With this study we tested the hypothesis that a neuromuscular blockade can result in a decreased P (leak) of the PLMA.

METHODS

The P (leak) of the PLMA was studied in 73 female patients under total intravenous anaesthesia with propofol (0.1 - 0.15 mg kg (-1) min (-1)) and remifentanil (0.1 - 0.3 microg kg (-1) min (-1)) before and after a complete neuromuscular blockade produced by intravenous injection of 0.6 mg kg (-1) Rocuronium.

RESULTS

The P (leak) decreased by more than 10 % of the baseline P (leak) in 8 out of 73 patients (11 %); however, in the entire study population there was no significant difference between the mean baseline P (leak) (28.5 +/- 7.3 cm H(2)O) and the mean P (leak) after complete neuromuscular blockade (29.1 +/- 7.0 cm H(2)O); (p = 0.128).

CONCLUSION

No general correlation between application of a neuromuscular blocking agent and a decrease of the mean P (leak) was found. However, the decrease of the P (leak) by more than 10 % in 11 % of the patients shows that in certain patients the application of neuromuscular blocking agents can result in a decreased P (leak) of the PLMA and indicates the necessity to control the P (leak) of the PLMA under complete muscle paralysis preoperatively when neuromuscular blocking agents are used.

Use of the LMA-ProSeal® in an Experimental Pig Model - A Potential Animal Model for Laryngeal Mask Airway Research: Results of a Pilot Study

OBJECTIVE

In light of the increased use of the LMA-ProSeal (P-LMA) it seems desirable to consider the P-LMA for prolonged surgical cases or post-operative ventilation. Long-term use could carry the risk of serious complications. An experimental pig model could be used to gain basic knowledge about long-term use before conducting clinical trails. In this randomized controlled study we tested the hypothesis if prolonged positive pressure ventilation (PPV) with the P-LMA in the pig is possible.

METHODS

The P-LMA was used for airway maintenance under general anaesthesia and PPV in 15 German country pigs. Randomised into 3 groups, the animals were ventilated for 90, 150 and 390 minutes, respectively. Arterial blood gas measurements were used to determine adequacy of ventilation. Airway leak pressure (P (leak)) and maximum tidal volume (TV) were measured in the supine, lateral and prone positions. A bronchoscopic examination was performed to detect signs of aspiration.

RESULTS

Adequate ventilation was demonstrated both after 120 min (4.7 +/- 0.4 kPa) and 360 min (4.7 +/- 0.5 kPa). The corresponding PaO(2) at FiO(2) = 1.0 was 59 +/- 5 kPa and 64 +/- 10 kPa, respectively. The mean P (leak) was 34 +/- 7 cm H(2)O. Change of position did not result in any significant change in P(leak) or maximum TV kg (-1). There was no bronchoscopic evidence of aspiration in any pig.

CONCLUSION

It was possible to ensure sufficient PPV with the P-LMA in the pig over different periods of time and in different body positions without any complications of airway management. The P-LMA can be used for PPV in the pig for durations of up to 390 minutes. We conclude that investigations into the long-term use of the LMA can be carried out in a pig model.

Videolaryngoskopie zur modifizierten „Rapid-sequence-Narkoseeinleitung“

BACKGROUND

There is evidence that cricoid pressure, one of the key elements of rapid sequence induction (RSI) in patients at risk of aspiration, can distort the glottic view obtained by direct laryngoscopy (DL) and consequently impair or delay endotracheal intubation (ETI). The fact that cricoid pressure is applied by an assistant "blindly", i.e. without any visual feedback, is believed to be a contributing factor. Video laryngoscopy (VIL) offers the advantage that both the anaesthetist and the assistant can follow laryngoscopy. This could be useful for ETI during RSI.

METHODS

We used VIL for a simulated RSI in 170 adult patients randomised to either video laryngoscopy-guided application of cricoid pressure (group I) or conventional, i.e. "blind", application of cricoid pressure (group II). Time to ETI was compared between groups. The laryngoscopy view obtained by VIL was compared with the view of conventional DL obtained before, in all patients.

RESULTS

Time to ETI did not differ between groups (p=0.2): 25.1+/-14.2 s (group I) vs. 23.7+/-12.1 s (group II). Laryngoscopy scores were significantly better for VIL than conventional DL (p<0.001).

CONCLUSIONS

Visualisation of the larynx during RSI can be improved using VIL. Time to ETI is not decreased by use of video laryngoscopy-guided application of cricoid pressure.

Airway management practices at German university and university-affiliated teaching hospitals--equipment, techniques and training: results of a nationwide survey

BACKGROUND

Until recently, Germany did not have national airway management guidelines. This survey collected comprehensive data on departmental airway management practices from German teaching institutions to identify weaknesses, and the results are presented here. German national airway guidelines were formulated by an expert group on the basis of these data and the current evidence in the literature.

METHODS

Questionnaires were mailed to the directors of 452 university and university-affiliated anaesthesia departments. They were asked to respond to 39 questions on the use of particular equipment and techniques, management of the difficult airway and training in airway management.

RESULTS

Two hundred and twelve questionnaires were returned. Many alternative devices for endotracheal intubation, such as the Bullard laryngoscope, the Bonfils laryngoscope and the Trachlight, are not used in the majority (80%) of departments. Thirty-six per cent of departments do not have difficult airway carts. No departmental difficult airway management plan is used in 22% of departments. Patients are not provided with written information on their personal airway management difficulties in 14% of departments. Structured training in the form of block rotation is offered in only 29-40% of departments. Although trainees perform fibreoptic intubation (FOI) in most departments, appropriate training in FOI is not available in some departments (8%).

CONCLUSION

There are deficits in various areas of airway management, in particular training and the use of algorithms. International guidelines and recommendations are not followed by a large number of German teaching institutions. The provision of German national airway guidelines should improve this situation.

Einsatz der ProSeal®-Kehlkopfmaske der Größe 3 bei Kindern

BACKGROUND

The low-pressure airway seal of the Classic laryngeal mask airway (CLMA) can be inadequate for positive pressure ventilation (PPV) in children. The ProSeal laryngeal mask airway (PLMA) forms a more effective seal of the airway than the CLMA and facilitates gastric tube placement in adults. The size 3 PLMA can be used in adults and children.

METHODS

The CLMA and PLMA were studied in random order -- crossover -- in 30 anaesthetized, non-paralysed children (average age 10.6 years, average body weight 39 kg). Airway leak pressure, maximum tidal volume, ease of insertion, quality of initial airway and fiberoptic position were determined. Gastric tube placement was assessed for the PLMA.

RESULTS

The mean airway leak pressure in neutral head position (27.0 vs. 16.8 cm H(2)O), maximum flexion (38.3 vs. 26.2 cm H(2)O) and maximum extension (21.1 vs. 14.2 cm H(2)O) as well as the mean maximum tidal volume (1432 vs. 1062 ml) were significantly higher (p<0.001) for the PLMA. Air insufflation into the stomach occurred with the CLMA but not with the PLMA. Gastric tube placement was possible in all patients.

CONCLUSIONS

The high reliability of g-tube placement and the significantly increased airway leak pressure seem to make the size 3 PLMA a more suitable device for PPV in children than the same size CLMA.

Use of the ProSeal laryngeal mask airway for pressure-controlled ventilation with and without positive end-expiratory pressure in paediatric patients: a randomized, controlled study

BACKGROUND

Tracheal intubation and positive end-expiratory pressure (PEEP) are frequently used in children to avoid airway closure and atelectasis during general anaesthesia. Also, the laryngeal mask airway (LMA(dagger)) is frequently used. However, one of the limitations with its use in children is that its low-pressure seal is often inadequate for positive pressure ventilation with PEEP. The ProSeal LMA (PLMA) has been shown to form a more effective seal than the Classic LMA. The ability to apply PEEP with the PLMA might improve gas exchange during positive pressure ventilation in children when the LMA is used.

METHODS

Twenty anaesthetized, non-paralysed children aged 55 (range 27-89) months, weighing 18 (sd 3) kg, were randomly allocated into two groups. Anaesthesia management and positive pressure ventilation were standardized. Size 2 and 2(1/2) PLMA were used. Artificial ventilation in Group I was with pressure controlled ventilation (PCV) and PEEP=5 cm H(2)O, in Group II with PCV without PEEP. A Fi(o(2)) = 1.0 was used for 20 min during induction of anaesthesia. Sixty minutes after induction of anaesthesia an arterial blood gas sample was taken under a Fi(o(2)) = 0.3.

RESULTS

Groups were comparable with respect to demographic data. Pa(o(2)) in Group I [22.1 (1.6) kPa] was significantly (P=0.001) higher than in Group II [19.2 (1.7) kPa].

CONCLUSIONS

The PLMA can be used for PCV with PEEP in paediatric patients. Application of PEEP improves gas exchange.

[Use of the laryngeal mask airway at german university and university-affiliated hospitals -- results of a nationwide survey]

AIM OF THE STUDY

The aim of this study was to collect comprehensive data on the use of the laryngeal mask airway (LMA) under general anaesthesia at German university and university-affiliated hospitals.

METHODS

Questionnaires were mailed to the directors of 452 German university and university-affiliated anaesthesia departments. Twenty-three questions related to the way and frequency of use of the LMA were asked.

RESULTS

Data from 212 departments (47 %) could be included into the analysis. The LMA is used in all departments. Depending on the size of the department the LMA is used in 1 - 60 % of all anaesthetics. The LMA is used significantly more often (p > 0.001) in smaller departments providing up to 10 000 anaesthetics per year compared to larger departments providing up to, or more than, 20 000 anaesthetics per year. Controlled ventilation is the preferred mode of ventilation in more than 75 % of all departments. The LMA is used "routinely" or "always" for operations lasting more than 1 hour in more than 75 % of all departments. The LMA is used in the areas of ear, nose, and throat, maxillofacial, and eye surgery "routinely" or "always" only in 11 - 26 % of all departments.

CONCLUSION

The role of the LMA in routine anaesthesia practice has clearly increased. Controversial aspects of use are reflected in the practice patterns of LMA use in different departments. The LMA has not been disseminated widely in the areas of ear, nose and throat-, maxillofacial- and eye surgery.

Measurement of dijet azimuthal decorrelations at central rapidities in pp collisions at sqrt s =1.96 TeV

Correlations in the azimuthal angle between the two largest transverse momentum jets have been measured using the D0 detector in p (-)p collisions at a center-of-mass energy sqrt[s]=1.96 TeV. The analysis is based on an inclusive dijet event sample in the central rapidity region corresponding to an integrated luminosity of 150 pb(-1). Azimuthal correlations are stronger at larger transverse momenta. These are well described in perturbative QCD at next-to-leading order in the strong coupling constant, except at large azimuthal differences where contributions with low transverse momentum are significant.

Size 2 ProSeal™ laryngeal mask airway: a randomized, crossover investigation with the standard laryngeal mask airway in paediatric patients

BACKGROUND

One of the main concerns with the use of the standard laryngeal mask airway (SLMA) in small infants is that its low-pressure seal might be inadequate for positive pressure ventilation so that there is a risk of gas leakage into the stomach with the subsequent risk of regurgitation. The new ProSeal LMA (PLMA) has been shown to form a more effective seal than the SLMA and to facilitate gastric tube placement in adults. The first paediatric size PLMA became available recently.

METHODS

Thirty anaesthetized, non-paralysed children aged 46 (19) months, weighing 16 (10-21) kg, were studied. The SLMA and PLMA were inserted in random order into each patient. Airway leak pressure and maximum tidal volume were measured. Ease of insertion, quality of initial airway and fibreoptic position were also determined. Gastric tube placement was assessed for the PLMA.

RESULTS

The airway leak pressure and maximum tidal volume were significantly higher for the PLMA (P=0.001). Ease of insertion and quality of initial airway were similar for both devices. Air entry into the stomach occurred more frequently with the SLMA (P=0.005). Gastric tube placement was possible in all patients.

CONCLUSIONS

The size 2 PLMA offered some advantages over the same size of SLMA in this crossover investigation. The high reliability of gastric tube placement and the significantly increased airway leak pressure might have important implications for use of this device for positive pressure ventilation in infants.

Search for supersymmetry with gauge-mediated breaking in diphoton events at D0

We report the results of a search for supersymmetry (SUSY) with gauge-mediated breaking in the missing transverse energy distribution of inclusive diphoton events using 263 pb(-1) of data collected by the D0 experiment at the Fermilab Tevatron Collider in 2002-2004. No excess is observed above the background expected from standard model processes, and lower limits on the masses of the lightest neutralino and chargino of about 108 and 195 GeV, respectively, are set at the 95% confidence level. These are the most stringent limits to date for models with gauge-mediated SUSY breaking with a short-lived neutralino as the next-to-lightest SUSY particle.

Measurement of the B0s lifetime in the exclusive decay channel B0s-->J/psiphi

Using the exclusive decay B0s-->J/psi(mu+mu-)phi(K+K-), we report the most precise single measurement of the B0s lifetime. The data sample corresponds to an integrated luminosity of approximately 220 pb(-1) collected with the D0 detector at the Fermilab Tevatron Collider in 2002-2004. We reconstruct 337 signal candidates, from which we extract the B0s lifetime, tau(B0s)=1.444(+0.098)(-0.090)(stat)+/-0.020(sys) ps. We also report a measurement for the lifetime of the B0 meson using the exclusive decay B0-->J/psi(mu+mu-)K*0(892)(K+pi-). We reconstruct 1370 signal candidates, obtaining tau(B0)=1.473(+0.052)(-0.050)(stat)+/-0.023(sys) ps, and the ratio of lifetimes, tau(B0s)/tau(B0)=0.980(+0.076)(-0.071)(stat)+/-0.003(sys).

Observation and properties of the X(3872) decaying to J/psipi(+)pi(-) in pp collisions at sqrt[s]=1.96 TeV

We report the observation of the X(3872) in the J/psipi(+)pi(-) channel, with J/psi decaying to mu(+)mu(-), in pp collisions at sqrt[s]=1.96 TeV. Using approximately 230 pb(-1) of data collected with the Run II D0 detector, we observe 522+/-100 X(3872) candidates. The mass difference between the X(3872) state and the J/psi is measured to be 774.9+/-3.1(stat)+/-3.0(syst) MeV/c(2). We have investigated the production and decay characteristics of the X(3872) and find them to be similar to those of the psi(2S) state.

Search for doubly charged higgs boson pair production in the decay to mu(+)mu(+)mu(-)mu(-) in pp collisions at sqrt[s]=1.96 TeV

A search for pair production of doubly charged Higgs bosons in the process pp -->H(++)H(--) -->mu(+)mu(+)mu(-)mu(-) is performed with the D0 run II detector at the Fermilab Tevatron. The analysis is based on a sample of inclusive dimuon data collected at an energy of sqrt[s]=1.96 TeV, corresponding to an integrated luminosity of 113 pb(-1). In the absence of a signal, 95% confidence level mass limits of M(H(+/-+/-)(L))>118.4 GeV/c(2) and M(H(+/-+/-)(R))>98.2 GeV/c(2) are set for left-handed and right-handed doubly charged Higgs bosons, respectively, assuming 100% branching into muon pairs.

[Can sevoflurane save time in routine clincal use? A comparison with halothane in pediatric anesthesia]

The volatile agent sevoflurane enables a rapid emergence from anaesthesia. The aim of this study was to investigate the possibility of increasing turnover in pediatric anaesthetic cases by use of sevoflurane in comparison with halothane. Often short cases or day cases need rapid turnover.

METHODS AND PATIENTS

The pediatric patients aged 4-14 years (ASA I) presenting for elective ophthalmic surgery were randomised to either the halothane or the sevoflurane group. Standard monitoring was applied to all patients, in addition the pEEG was used to determine comparable anaesthetic depth. Sevoflurane or halothane were titrated to a SEF 90 of 8-12 Hz. Management of the airway was done with the RLMA (reinforced laryngeal mask). All patients were under controlled ventilation. At the end of surgery and anaesthesia 3 time intervals were measured: phase I) end of anaesthetic application--start of spontaneous respiration; phase II) start of spontaneous respiration--removal of RLMA. The SEF 90 interval was also assessed.

RESULTS

18 cases were included (halo n = 8/sevo n = 10, no significant differences concerning weight, age, anaesthesia time). There is a significant advantage for the Sevoflurane group in phase II of 6.8 minutes. No differences were seen in phase I and SEF 90 interval.

CONCLUSION

Sevoflurane offers the potential for shortening turnover in pediatric anaesthesia.

Effects of anti-C5a monoclonal antibodies on oxygen use in a porcine model of severe sepsis

METHODS

We analysed the effects of complement depletion and of C5a inhibition on haemodynamic parameters, oxygen delivery (DO2), oxygen consumption (VO2), oxygen extraction ratio (OER) and blood lactate levels after live bacteria infusion in pigs.

RESULTS

In the first series of experiments, animals were decomplemented by cobra venom factor (CVF, 125 micrograms kg-1) and challenged with 1.3 x 10(9) Escherichia coli kg-1. In a second series, animals were treated with neutralizing anti-C5a monoclonal antibodies (mAb) T13/9 before infusion of an increased E. coli dosage (1 x 10(10) E. coli kg-1). Administration of Gram-negative bacteria resulted in hypotension, tachycardia, pulmonary hypertension and decreased cardiac output typical for severe sepsis. These alterations were more pronounced in animals challenged with a higher bacteria concentration (1 x 10(10) E. coli kg-1, n = 5) than with a lower dosage (1.3 x 10(9) E. coli kg-1, n = 4). Complement depletion by CVF injection 24 h before E. coli infusion (n = 4), or anti-C5a mAb T13/9 administration (n = 4) had no effect on the changes in haemodynamic parameters and in DO2 associated with E. coli challenge. Application of either 1.3 x 10(9) or 1 x 10(10) E. coli kg-1 resulted in a marked decrease in VO2 and an increase in blood lactate levels, whereas the OER did not change throughout the experiment. In contrast, pretreatment with CVF 24 h before low-dose E. coli (1.3 x 10(9) kg-1) administration resulted in a significant increase in VO2 (P < 0.05) and in OER (P < 0.05) compared with untreated septic animals (n = 4). No hyperlactaemia occurred in complement-depleted septic animals compared with complement-sufficient animals (P < 0.05). Animals challenged with a high E. coli dose (1 x 10(1) kg-1) and treated with anti-C5a mAbs showed a pronounced increase in VO2 and OER (P < 0.05) accompanied by an attenuated increase in lactate levels (P < 0.05) compared with untreated septic animals.

CONCLUSION

The results demonstrate an improved oxygen use after complement depletion in this model of severe Gram-negative sepsis. Furthermore, a similar effect was seen after specifically neutralizing C5a by mAbs, indicating a role of C5a in the underlying mechanism.

An immunological and chromatographic comparison of human intrinsic factor and the acid-stable gastric esterase VI A

When examined by immunoelectrophoresis and double-gel diffusion, gastric acid-stable esterase (VI A) and human intrinsic factor (IF) behaved as different substances. The VI A migrated in agar-gel electrophoresis mainly as a β₂/β₁-globulin and IF as β₁/α₂-globulin. Both showed overlapping migration and diffusion near the starting point. On DEAE-chromatography IF was eluted together with VI A at 0·05–0·075 M, pH 7·0. In gel filtration experiments with Sephadex G 100 and G 200, the IF from in vivo neutralized gastric juice (NGJ) and from gastric mucosa (GM) was eluted in a definite range according to its molecular weight of 60,000. No IF was found in acid gastric juice (AGJ).

Two immunologically identical variants of VI A were eluted at two different ranges when NGJ and GM were used for gel filtration. The variant of VI A with the lower molecular weight was eluted together with IF. When AGJ was used, only the VI A with the higher molecular weight was found and in an elution range quite different from that for IF. Of the purified substances, only IF showed vitamin B₁₂ binding, which could be inhibited by serum from a patient with pernicious anaemia, and only heteroimmune serum against this B₁₂-binding fraction contained IF antibodies of the blocking and binding types.

IF and VI A proved to be biochemically and immunologically distinct proteins.