Identifying the real-world challenges of dysplasia surveillance in inflammatory bowel disease: a retrospective cohort study in a tertiary health network.

BACKGROUND: Dysplasia surveillance in inflammatory bowel disease (IBD) is often suboptimal and deviates from guidelines. AIMS: To assess dysplasia surveillance behaviours and adherence to guidelines amongst a large tertiary teaching health network with a specialised IBD unit to identify areas where dysplasia surveillance could be improved. METHODS: A retrospective audit of IBD surveillance colonoscopy practice over an 18-month period was performed using the Provation Endoscopy Database and the hospital's primary sclerosing cholangitis database. RESULTS: The audit identified 115 dysplasia surveillance colonoscopies. A total of 37% of index dysplasia colonoscopies were outside recommended guidelines. A total of 10% had inadequate bowel preparation and only 40% had excellent bowel preparation. A total of 28% of patients underwent dye-based chromoendoscopy and 69% underwent high-definition white-light endoscopy. Dye chromoendoscopy was more likely to be used by IBD specialists than interventional endoscopists (P = 0.008) and other endoscopists (P = 0.004). Only IBD specialists and interventional endoscopists used dye chromoendoscopy. Dysplasia or colorectal cancer was detected in 3.4% of the colonoscopies. Overall, the several dysplasia examinations were lower than expected. CONCLUSIONS: Dysplasia surveillance in the IBD population remains an area of improvement given the current national guidelines. IBD specialists are more likely to perform dye chromoendoscopy than other endoscopists/gastroenterologists. Dysplasia rates in this real-world contemporary setting are less than expected in historical studies and may represent improvements in IBD management principles and medications.

Endoscopic ultrasound-guided gallbladder and bile duct drainage with lumen apposing metal stent: A large multicenter cohort (with videos).

BACKGROUND AND AIM: Cholecystectomy and endoscopic retrograde cholangiopancreatography are the gold standard for managing acute cholecystitis and malignant biliary obstruction, respectively. Recent advances in therapeutic endoscopic ultrasound (EUS) have provided alternatives for managing patients in whom these approaches fail, namely, EUS-guided gallbladder drainage (EUS-GB) and EUS-guided bile duct drainage (EUS-BD). We aimed to assess the technical and clinical success of these techniques in the largest multicenter cohort published to date. METHODS: A retrospective, multicenter, observational study involving 17 centers across Australia and New Zealand was conducted. All patients who had EUS-GB or EUS-BD performed in a participating center using a lumen apposing metal stent between 2016 and 2020 were included. Primary outcome was technical success, defined as intra-procedural successful drainage. Secondary outcomes included clinical success and 30-day mortality. RESULTS: One hundred and fifteen patients underwent EUS-GB (n = 49) or EUS-BD (n = 66). EUS-GB was technically successful in 47 (95.9%) while EUS-BD was successful in 60 (90.9%). All failed cases were due to maldeployment of the distal flange outside of the targeted lumen. Clinical success of EUS-GB was achieved in 39 (79.6%). No patients required subsequent cholecystectomy. Clinical success of EUS-BD was achieved in 52 (78.8 %). Thirty-day mortality was 14.3% for EUS-GB and 12.1% for EUS-BD. CONCLUSIONS: EUS-guided gallbladder drainage and EUS-BD are promising alternatives for managing nonsurgical candidates with cholecystitis and malignant biliary obstruction following failed endoscopic retrograde pancreatography. Both techniques delivered high technical success with acceptable clinical success. Further research is needed to investigate the gap between technical and clinical success.

Measurement of cortical elasticity in Drosophila melanogaster embryos using ferrofluids.

Many models of morphogenesis are forced to assume specific mechanical properties of cells, because the actual mechanical properties of living tissues are largely unknown. Here, we measure the rheology of epithelial cells in the cellularizing Drosophila embryo by injecting magnetic particles and studying their response to external actuation. We establish that, on timescales relevant to epithelial morphogenesis, the cytoplasm is predominantly viscous, whereas the cellular cortex is elastic. The timescale of elastic stress relaxation has a lower bound of 4 min, which is comparable to the time required for internalization of the ventral furrow during gastrulation. The cytoplasm was measured to be ∼103-fold as viscous as water. We show that elasticity depends on the actin cytoskeleton and conclude by discussing how these results relate to existing mechanical models of morphogenesis.

Immunomodulator use does not prevent first loss of response to anti-tumour necrosis factor alpha therapy in inflammatory bowel disease: long-term outcomes in a real-world cohort.

BACKGROUND: Recent prospective studies suggest combination therapy with immunomodulators improves efficacy, but long-term data is limited. AIM: To assess whether anti-tumour necrosis factor alpha (anti-TNF) monotherapy was associated with earlier loss of response (LOR) than combination therapy in a real-world cohort with long-term follow up. METHODS: A retrospective audit was conducted of inflammatory bowel disease patients receiving anti-TNF therapy in a tertiary centre and specialist private practices. All patients with accurate data for anti-TNF commencement and adequate correspondence to determine end-points were included. Outcomes measured included time to first LOR, causes and biochemical parameters. RESULTS: Two hundred and twenty-four patients were identified; 139 (62.1%) on combination therapy and 85 (37.9%) on monotherapy. Forty-five percent of patients had LOR during follow up until a maximum of 8.5 years; 59.4% on combination therapy and 40.6% on monotherapy (P = 0.533). The median time to LOR was not different between groups; 1069 days for combination therapy and 1489 days for monotherapy (P = 0.533). There was no difference in time to LOR between patients treated with different combination regimens or different anti-TNF agents. CONCLUSION: In this large cohort of patients in a real-world setting, patients treated with anti-TNF monotherapy had similar rates of LOR as patients on anti-TNF combination therapy, at both short- and long-term follow up.

New 4-Amino-1,2,3-Triazole Inhibitors of Indoleamine 2,3-Dioxygenase Form a Long-Lived Complex with the Enzyme and Display Exquisite Cellular Potency.

Indoleamine-2,3 dioxygenase 1 (IDO1) has emerged as a central regulator of immune responses in both normal and disease biology. Due to its established role in promoting tumour immune escape, IDO1 has become an attractive target for cancer treatment. A novel series of highly cell potent IDO1 inhibitors based on a 4-amino-1,2,3-triazole core have been identified. Comprehensive kinetic, biochemical and structural studies demonstrate that compounds from this series have a noncompetitive kinetic mechanism of action with respect to the tryptophan substrate. In co-complex crystal structures, the compounds bind in the tryptophan pocket and make a direct ligand interaction with the haem iron of the porphyrin cofactor. It is proposed that these data can be rationalised by an ordered-binding mechanism, in which the inhibitor binds an apo form of the enzyme that is not competent to bind tryptophan. These inhibitors also form a very tight, long-lived complex with the enzyme, which partially explains their exquisite cellular potency. This novel series represents an attractive starting point for the future development of potent IDO1-targeted drugs.

Carbon Dioxide Insufflation Increases Colonoscopic Adenoma Detection Rate Compared With Air Insufflation.

GOALS: To determine the effect of carbon dioxide insufflation on the most important outcome measure of colonoscopic quality: adenoma detection rate (ADR). BACKGROUND: Bowel cancer is the second most common cause of cancer deaths in males and females in Australia. Carbon dioxide has in recent times become the insufflation methodology of choice for screening colonoscopy for bowel cancer, as this has been shown to have significant advantages when compared with traditional air insufflation. STUDY: Endoscopies performed over a period of 9 months immediately before and after the implementation of carbon dioxide insufflation at endoscopy centers were eligible for inclusion. RESULTS: The difference in ADR between the carbon dioxide and air insufflation methods was statistically significant, with an increased ADR in the carbon dioxide group. The superiority of carbon dioxide insufflation was sustained with a logistic regression model, which showed ADR was significantly impacted by insufflation method. CONCLUSIONS: Carbon dioxide insufflation is known to reduce abdominal pain, postprocedural duration of abdominal pain, abdominal distension, and analgesic requirements. This study represents for the first time the beneficial effect of carbon dioxide insufflation upon the key quality colonoscopy indicator of ADR.

Endoscopic ultrasound-guided fine-needle aspirate-derived preclinical pancreatic cancer models reveal panitumumab sensitivity in KRAS wild-type tumors.

Pancreatic cancer (PC) is largely refractory to existing therapies used in unselected patient trials, thus emphasizing the pressing need for new approaches for patient selection in personalized medicine. KRAS mutations occur in 90% of PC patients and confer resistance to epidermal growth factor receptor (EGFR) inhibitors (e.g., panitumumab), suggesting that KRAS wild-type PC patients may benefit from targeted panitumumab therapy. Here, we use tumor tissue procured by endoscopic ultrasound-guided fine-needle aspirate (EUS-FNA) to compare the in vivo sensitivity in patient-derived xenografts (PDXs) of KRAS wild-type and mutant PC tumors to panitumumab, and to profile the molecular signature of these tumors in patients with metastatic or localized disease. Specifically, RNASeq of EUS-FNA-derived tumor RNA from localized (n = 20) and metastatic (n = 20) PC cases revealed a comparable transcriptome profile. Screening the KRAS mutation status of tumor genomic DNA obtained from EUS-FNAs stratified PC patients into either KRAS wild-type or mutant cohorts, and the engraftment of representative KRAS wild-type and mutant EUS-FNA tumor samples into NOD/SCID mice revealed that the growth of KRAS wild-type, but not mutant, PDXs was selectively suppressed with panitumumab. Furthermore, in silico transcriptome interrogation of The Cancer Genome Atlas (TCGA)-derived KRAS wild-type (n = 38) and mutant (n = 132) PC tumors revealed 391 differentially expressed genes. Taken together, our study validates EUS-FNA for the application of a novel translational pipeline comprising KRAS mutation screening and PDXs, applicable to all PC patients, to evaluate personalized anti-EGFR therapy in patients with KRAS wild-type tumors.

Passive mechanical forces control cell-shape change during Drosophila ventral furrow formation.

During Drosophila gastrulation, the ventral mesodermal cells constrict their apices, undergo a series of coordinated cell-shape changes to form a ventral furrow (VF) and are subsequently internalized. Although it has been well documented that apical constriction is necessary for VF formation, the mechanism by which apical constriction transmits forces throughout the bulk tissue of the cell remains poorly understood. In this work, we develop a computational vertex model to investigate the role of the passive mechanical properties of the cellular blastoderm during gastrulation. We introduce to our knowledge novel data that confirm that the volume of apically constricting cells is conserved throughout the entire course of invagination. We show that maintenance of this constant volume is sufficient to generate invagination as a passive response to apical constriction when it is combined with region-specific elasticities in the membranes surrounding individual cells. We find that the specific sequence of cell-shape changes during VF formation is critically controlled by the stiffness of the lateral and basal membrane surfaces. In particular, our model demonstrates that a transition in basal rigidity is sufficient to drive VF formation along the same sequence of cell-shape change that we observed in the actual embryo, with no active force generation required other than apical constriction.

Structure of human Bloom's syndrome helicase in complex with ADP and duplex DNA.

Bloom's syndrome is an autosomal recessive genome-instability disorder associated with a predisposition to cancer, premature aging and developmental abnormalities. It is caused by mutations that inactivate the DNA helicase activity of the BLM protein or nullify protein expression. The BLM helicase has been implicated in the alternative lengthening of telomeres (ALT) pathway, which is essential for the limitless replication of some cancer cells. This pathway is used by 10-15% of cancers, where inhibitors of BLM are expected to facilitate telomere shortening, leading to apoptosis or senescence. Here, the crystal structure of the human BLM helicase in complex with ADP and a 3'-overhang DNA duplex is reported. In addition to the helicase core, the BLM construct used for crystallization (residues 640-1298) includes the RecQ C-terminal (RQC) and the helicase and ribonuclease D C-terminal (HRDC) domains. Analysis of the structure provides detailed information on the interactions of the protein with DNA and helps to explain the mechanism coupling ATP hydrolysis and DNA unwinding. In addition, mapping of the missense mutations onto the structure provides insights into the molecular basis of Bloom's syndrome.

Targeting the PPM1D phenotype; 2,4-bisarylthiazoles cause highly selective apoptosis in PPM1D amplified cell-lines.

The metal-dependent phosphatase PPM1D (WIP1) is an important oncogene in cancer, with over-expression of the protein being associated with significantly worse clinical outcomes. In this communication we describe the discovery and optimization of novel 2,4-bisarylthiazoles that phenocopy the knockdown of PPM1D, without inhibiting its phosphatase activity. These compounds cause growth inhibition at nanomolar concentrations, induce apoptosis, activate p53 and display impressive cell-line selectivity. The results demonstrate the potential for targeting phenotypes in drug discovery when tackling challenging targets or unknown mechanisms.

Repetitive endoscopic drainage as initial intervention is safe and effective for early treatment of pancreatic necrotic collections.

BACKGROUND: While endoscopic step-up approach with delayed drainage (more than 28 days from diagnosis) was shown to produce the best outcomes in the treatment of pancreatic walled-off necrosis (WON), we assessed our single centre experience of early versus delayed endoscopic drainage of pancreatic necrotic collections. METHODS: Patients who underwent endoscopic drainage of pancreatic necrotic collections between 2011 and 2022 under Monash Health were identified. They were excluded if below 18 years old or their follow up data were missing. The included patients' medical records, pathology results, and imaging findings were retrospectively reviewed. RESULTS: A total of 60 patients were included. 31.58% required percutaneous drainage and 15% received either endoscopic or surgical necrosectomy. The disease related mortality was 8.47% and the average length of stay (LOS) was 70.92 days. No significant difference was shown in disease-related mortality (10.5% vs. 7.5%, P = 0.697) or LOS (75.35 vs. 68.7, P = 0.644) between early and delayed drainage cohorts, but patients who received early drainage have higher qSOFA score on the day of drainage (2 vs. 0, P = 0.004). DISCUSSION: Repetitive endoscopic drainage with selective percutaneous drainage is effective in the management of pancreatic necrotic collections. Early drainage should be considered in patients who developed severe sepsis.

Needle knife sphincterotomy does not increase the risk of pancreatitis in patients with difficult biliary cannulation.

BACKGROUND & AIMS: Biliary cannulation is unsuccessful during 5%-10% of endoscopic retrograde cholangiopancreatography (ERCP) procedures. Needle knife sphincterotomy (NKS) can improve success of cannulation but is often used as a last resort and is associated with post-ERCP pancreatitis (PEP). We evaluated the safety and efficacy of performing NKS during early stages of difficult cannulation and the relationship between difficult cannulation and the risk of PEP. METHODS: We performed a prospective trial of consecutive patients with an intact papilla who were undergoing ERCP at tertiary referral center; 73 patients were defined as having difficult biliary cannulation according to predefined cannulation parameters. These patients were randomly assigned to groups that received either NKS or continued standard cannulation. Main outcome measures were PEP and successful biliary cannulation. RESULTS: Of 464 patients with an intact papilla undergoing ERCP, 73 met the criteria for difficult cannulation. Cannulation success in difficult cannulation cases was 86%, with a PEP rate of 19%. There was no difference in eventual cannulation success between the groups. However, 65% of the patients assigned to the standard cannulation group required crossover to NKS. There was no significant difference in development of PEP among patients in the early NKS group (20.5%) vs standard cannulation (17.6%). Pancreatic duct stents were inserted in 23 of the patients in the early NKS arm and in 15 in the standard cannulation arm. The number of cannulation attempts (more than 7) increased the risk of PEP (P < .01). On the basis of multivariate analysis, independent risk factors for PEP were failure of early cannulation and failure of biliary cannulation. CONCLUSIONS: Early application of NKS during difficult cannulation does not increase the risk of PEP. The risk of PEP increases greatly after 7-8 attempts at or failure of cannulation. Further studies are required to assess whether early implementation of NKS during difficult cannulation reduces the development of PEP. Australia and New Zealand Clinical Trials registry: ANZTRN 12,612,000,060,842.

An optogenetic tool to inhibit RhoA in Drosophila embryos.

We describe a protocol for optogenetic inhibition of the small GTPase Rho1 (RhoA) in Drosophila embryos, which allows rapid and spatially confined inactivation of Rho1 and Rho1-mediated actomyosin contractility. We provide step-by-step instruction for optogenetic manipulations of Drosophila embryos using confocal and multiphoton imaging systems. This tool is useful for determining the site- and stage-specific function of Rho1 in Drosophila embryos and for studying the immediate tissue response to acute elimination of cellular contractility. For complete details on the use and execution of this protocol, please refer to Guo et al. (2022).1.

Optogenetic Inhibition of Rho1-Mediated Actomyosin Contractility Coupled with Measurement of Epithelial Tension in Drosophila Embryos.

Contractile forces generated by actin and non-muscle myosin II ("actomyosin contractility") are critical for morphological changes of cells and tissues at multiple length scales, such as cell division, cell migration, epithelial folding, and branching morphogenesis. An in-depth understanding of the role of actomyosin contractility in morphogenesis requires approaches that allow the rapid inactivation of actomyosin, which is difficult to achieve using conventional genetic or pharmacological approaches. The presented protocol demonstrates the use of a CRY2-CIBN based optogenetic dimerization system, Opto-Rho1DN, to inhibit actomyosin contractility in Drosophila embryos with precise temporal and spatial controls. In this system, CRY2 is fused to the dominant negative form of Rho1 (Rho1DN), whereas CIBN is anchored to the plasma membrane. Blue light-mediated dimerization of CRY2 and CIBN results in rapid translocation of Rho1DN from the cytoplasm to the plasma membrane, where it inactivates actomyosin by inhibiting endogenous Rho1. In addition, this article presents a detailed protocol for coupling Opto-Rho1DN-mediated inactivation of actomyosin with laser ablation to investigate the role of actomyosin in generating epithelial tension during Drosophila ventral furrow formation. This protocol can be applied to many other morphological processes that involve actomyosin contractility in Drosophila embryos with minimal modifications. Overall, this optogenetic tool is a powerful approach to dissect the function of actomyosin contractility in controlling tissue mechanics during dynamic tissue remodeling.

An unusual case of multiple gastrointestinal stromal tumors in the small bowel presenting as occult and overt gastrointestinal bleeding.

We present a case report of a 59-year-old woman with multiple gastrointestinal stromal tumors as a cause of gastrointestinal bleeding. She initially presented with recurrent iron deficiency anemia and subsequent gastrointestinal bleeding over 10 years. An initial angiodysplastic lesion was identified, treated, and spot tattooed. Recurrent symptoms occurred leading to repeat investigations with a further subepithelial lesion with ulceration being identified. Computerized tomography enterography subsequently revealed an ileal intraluminal enhancing lesion, and she was referred to surgery. Surgical resection was ultimately performed, and multiple lesions were found to be present with histology revealing multiple gastrointestinal stromal tumors.

Optogenetic inhibition of actomyosin reveals mechanical bistability of the mesoderm epithelium during Drosophila mesoderm invagination.

Apical constriction driven by actin and non-muscle myosin II (actomyosin) provides a well-conserved mechanism to mediate epithelial folding. It remains unclear how contractile forces near the apical surface of a cell sheet drive out-of-the-plane bending of the sheet and whether myosin contractility is required throughout folding. By optogenetic-mediated acute inhibition of actomyosin, we find that during Drosophila mesoderm invagination, actomyosin contractility is critical to prevent tissue relaxation during the early, 'priming' stage of folding but is dispensable for the actual folding step after the tissue passes through a stereotyped transitional configuration. This binary response suggests that Drosophila mesoderm is mechanically bistable during gastrulation. Computer modeling analysis demonstrates that the binary tissue response to actomyosin inhibition can be recapitulated in the simulated epithelium that undergoes buckling-like deformation jointly mediated by apical constriction in the mesoderm and in-plane compression generated by apicobasal shrinkage of the surrounding ectoderm. Interestingly, comparison between wild-type and snail mutants that fail to specify the mesoderm demonstrates that the lateral ectoderm undergoes apicobasal shrinkage during gastrulation independently of mesoderm invagination. We propose that Drosophila mesoderm invagination is achieved through an interplay between local apical constriction and mechanical bistability of the epithelium that facilitates epithelial buckling.

Does ERCP position matter? A randomized controlled trial comparing efficacy and complications of left lateral versus prone position (POSITION study).

Background and study aims Endoscopic retrograde cholangiopancreatography (ERCP) is traditionally performed with patients in the prone position (PP). However, this poses a potentially increased risk of anesthetic complications. An alternative is the left lateral (LL) decubitus position, which is commonly used for endoscopic procedures. Our aim was to compare cannulation rate, time, and outcomes in ERCP performed in LL versus PP. Patients and methods We conducted a non-inferiority, prospective, randomized control trial with 1:1 randomization to either LL or PP position. Patients > 18 years of age with native papillae requiring a therapeutic ERCP were recruited between March 2017 and November 2018 in a single tertiary center. Results A total of 253 patients were randomized; 132 to LL (52.2 %) and 121 to PP (47.8 %). Cannulation rates were 97.0 % in LL vs 99.2 % in PP (difference -2.2 % (one-sided 95 % CI: -5 % to 0.6 %). Median time to biliary cannulation was 03:50 minutes in LL vs 02:57 minutes in PP ( P  = 0.62). Pancreatitis rates were 2.3 % in LL vs 5.8 % in PP ( P  = 0.20). There were significantly lower radiation doses used in PP (0.23 mGy/m 2 in LL vs 0.16 mGy/m 2 in PP, P  = 0.008) without a difference in fluoroscopy times. Conclusions Our analysis comparing LL to PP during ERCP shows comparable procedural and anesthetic outcomes, with significantly lower radiation exposure when performed in PP. We conclude that ERCP undertaken in the LL position is not inferior to PP, except for higher radiation exposure, and should be considered as a safe alternate position for patients undergoing ERCP.