Peri-operative SARS-CoV-2 infection increases postoperative mortality. The aim of this study was to determine the optimal duration of planned delay before surgery in patients who have had SARS-CoV-2 infection. This international, multicentre, prospective cohort study included patients undergoing elective or emergency surgery during October 2020. Surgical patients with pre-operative SARS-CoV-2 infection were compared with those without previous SARS-CoV-2 infection. The primary outcome measure was 30-day postoperative mortality. Logistic regression models were used to calculate adjusted 30-day mortality rates stratified by time from diagnosis of SARS-CoV-2 infection to surgery. Among 140,231 patients (116 countries), 3127 patients (2.2%) had a pre-operative SARS-CoV-2 diagnosis. Adjusted 30-day mortality in patients without SARS-CoV-2 infection was 1.5% (95%CI 1.4-1.5). In patients with a pre-operative SARS-CoV-2 diagnosis, mortality was increased in patients having surgery within 0-2 weeks, 3-4 weeks and 5-6 weeks of the diagnosis (odds ratio (95%CI) 4.1 (3.3-4.8), 3.9 (2.6-5.1) and 3.6 (2.0-5.2), respectively). Surgery performed ≥ 7 weeks after SARS-CoV-2 diagnosis was associated with a similar mortality risk to baseline (odds ratio (95%CI) 1.5 (0.9-2.1)). After a ≥ 7 week delay in undertaking surgery following SARS-CoV-2 infection, patients with ongoing symptoms had a higher mortality than patients whose symptoms had resolved or who had been asymptomatic (6.0% (95%CI 3.2-8.7) vs. 2.4% (95%CI 1.4-3.4) vs. 1.3% (95%CI 0.6-2.0), respectively). Where possible, surgery should be delayed for at least 7 weeks following SARS-CoV-2 infection. Patients with ongoing symptoms ≥ 7 weeks from diagnosis may benefit from further delay.

BACKGROUND AND PURPOSEThe glucagon-like peptides GLP-1 and GLP-2 are secreted from enteroendocrine L-cells following nutrient ingestion. Drugs that increase activity of the GLP-1 axis are highly successful therapies for type 2 diabetes, and boosting L-cell secretion is a potential strategy for future diabetes treatment. The aim of the present study was to further our understanding of the bile acid receptor GPBA (TGR5), an L-cell target currently under therapeutic exploration. EXPERIMENTAL APPROACHGLUTag cells and mixed primary murine intestinal cultures were exposed to bile acids and a specific agonist, GPBAR-A. Secretion was measured using hormone assays and intracellular calcium and cAMP responses were monitored using real-time imaging techniques. KEY RESULTSBile acid-triggered GLP-1 secretion from GLUTag cells was GPBA-dependent, as demonstrated by its abolition following tgr5 siRNA transfection. Bile acids and GPBAR-A increased GLP-1 secretion from intestinal cultures, with evidence for synergy between the effects of glucose and GPBA activation. Elevation of cAMP was observed following GPBA activation in individual GLUTag cells. Direct calcium responses to GPBAR-A were small, but in the presence of the agonist, a subpopulation of cells that was previously poorly glucose-responsive exhibited robust glucose responses. In vivo, increased delivery of bile to more distal regions of the ileum augmented L-cell stimulation. CONCLUSIONS AND IMPLICATIONSGPBA signalling in L-cells involves rapid elevation of cAMP, and enhanced calcium and secretory responses to glucose. Modulation of this receptor therapeutically may be an attractive strategy to enhance GLP-1 secretion and achieve better glycaemic control in diabetic patients. AbbreviationsCDCA, chenodeoxycholic acid; CFP, cyan fluorescent protein; DCA, deoxycholic acid; Epac, cAMP-guanine nucleotide exchange factors; fsk/IBMX, forskolin plus 3-isobutyl-1-methylxanthine; GLP-1, -2, glucagon-like peptide-1, -2; KATP, ATP-sensitive potassium channel; LCA, lithocholic acid; PYY, peptide YY; TLCA, taurolithocholic acid; YFP, yellow fluorescent protein BJP British Journal of Pharmacology

Test 63. VI+dermoscopy (in-person) -high experience (invasive melanoma or atypical intraepidermal melanocytic variants)...... Test 65. VI+dermoscopy (in-person) -trained observer (invasive melanoma or atypical intraepidermal melanocytic variants)..... Dermoscopy, with and without visual inspection, for diagnosing melanoma in adults (Review)

Aims/hypothesis To investigate the pathways by which cyclic AMP (cAMP) stimulates glucagon-like peptide-1 (GLP-1) secretion, using the GLUTag enteroendocrine cell line. Materials and methods GLP-1 release from GLUTag cells was measured in response to agents that increase cAMP, and single cells were studied by fluorescence calcium imaging and electrophysiology to evaluate the underlying pathways. Results Pituitary adenylate cyclase-activating polypeptide increased cAMP levels and stimulated GLP-1 release from GLUTag cells. Agents that increase cAMP levels, including forskolin plus 3-isobutyl-1-methylxanthine (fsk/IBMX), triggered a rise in the intracellular calcium concentration and enhanced the response to glucose by increasing both the number of cells responding to glucose and the magnitude of calcium responses in individual cells. Importantly, fsk/IBMX also stimulated GLP-1 release and intracellular calcium elevation even in the absence of nutrients. fsk/IBMX triggered membrane depolarisation and the firing of action potentials, associated with a +14 mV shift in the voltage-dependence of activation of hyperpolarisation-activated currents and the closure of a background potassium conductance. Conclusions/interpretation We show here that cAMP elevation directly triggers GLP-1 release and enhances the secretory response to other stimuli like glucose, by modulating hyperpolarisation-activated currents and the background potassium current. cAMP-elevating pathways and the cAMPmodulated conductances in L cells present important targets for the development of therapeutic GLP-1 secretagogues.