Effectiveness and safety of cold snare polypectomy and cold endoscopic mucosal resection for nonpedunculated colorectal polyps of 10-19 mm: a multicenter observational cohort study.

BACKGROUND : Cold snare polypectomy (CSP) is the standard of care for the resection of small (< 10 mm) colonic polyps. Limited data exist for its efficacy for medium-sized (10-19 mm) nonpedunculated polyps, especially conventional adenomas. This study evaluated the effectiveness and safety of CSP/cold endoscopic mucosal resection (C-EMR) for medium-sized nonpedunculated colonic polyps. METHODS : A prospective multicenter observational study was conducted of all morphologically suitable nonpedunculated colonic polyps of 10-19 mm removed by CSP/C-EMR between May 2018 and June 2021. Once resection was complete, multiple biopsies were taken of the margins circumferentially and centrally. The primary outcome was the incomplete resection rate (IRR), based on residual polyp in these biopsy specimens. Secondary outcomes were recurrence rate at first surveillance colonoscopy and rates of adverse events (AEs). RESULTS : CSP/C-EMR was performed for 350 polyps (median size 15 mm; 266 [76.0 %] Paris 0-IIa classification) in 295 patients. Submucosal injection was used for 87.1 % (n = 305) of polyps. Histology showed 68.6 % adenomas, 26.0 % sessile serrated lesions (SSLs) without dysplasia, 4.0 % SSL with dysplasia, and 1.4 % hyperplastic polyps. The IRRs based on margin or central biopsies being positive were 1.7 % (n = 6) and 0.3 % (n = 1), respectively. The polyp recurrence rate was 1.7 % (n = 4) at first surveillance colonoscopy - completed for 65.4 % (n = 229) of polyps at a median interval of 9.7 months. AEs occurred in 3.4 % (n = 10) of patients: four with post-polypectomy pain; three self-limiting post-polypectomy bleeds; two post-polypectomy-syndrome-like presentations; and one intraprocedural bleed treated with clips. There were no perforations. CONCLUSION : CSP/C-EMR for morphologically suitable nonpedunculated colonic polyps of 10-19 mm is effective and safe, including for conventional adenomas. Rates of incomplete resection and recurrence were low, with few AEs. Studies directly comparing this method with hot snare resection are required.

Drainage of pancreatic fluid collections using a lumen-apposing metal stent with an electrocautery-enhanced delivery system.

BACKGROUND AND AIM: Our aim was to evaluate the efficacy and safety of a lumen-apposing metal stent with an electrocautery-enhanced delivery system (EDS-LAMS) for endoscopic ultrasound (EUS)-guided drainage of pancreatic fluid collections (PFCs) in regular clinical practice. METHODS: A retrospective and subsequent prospective analysis was undertaken of all patients who underwent EUS-guided drainage of their PFCs using the EDS-LAMS at 17 tertiary therapeutic endoscopy centers. RESULTS: Two hundred eight cases of EDS-LAMS deployment were attempted in 202 patients (mean age 52.9 years) at time of evaluation. Ninety-seven patients had pancreatic pseudocysts (PPs), 75 walled-off pancreatic necrosis (WOPN), 10 acute peripancreatic fluid collections (APFCs), 6 acute necrotic collections (ANCs), and 14 postoperative collections (POCs). Procedural technical success was achieved in 202/208 cases (97.1%). Maldeployment occurred in 7/208 cases (3.4%). Clinical success was achieved in 142/160 (88.8%) patients (PP 90%, WOPN 85.2%, APFC 100%, ANC 75%, POC 100%). Delayed adverse events included stent migration in 15/202 (7.4%), stent occlusion and infection in 16/202 (7.9%), major bleeding in 4/202 (2%), and buried EDS-LAMS in 2/202 (1%). PFC recurrence occurred in 13/142 (9.2%) patients; 9/202 (4.5%) required surgical or radiological intervention for PFC management after EDS-LAMS insertion. CONCLUSIONS: This large international multicenter study evaluating the EDS-LAMS for drainage of PFCs in routine clinical practice suggests that the EDS-LAMS are safe and effective for drainage of all types of PFCs; however, further endoscopic therapy is often required for WOPN. Major bleeding was a rare complication in our cohort.

Searching for low phospholipid associated cholelithiasis among patients with post-cholecystectomy biliary pain.

INTRODUCTION: Low phospholipid associated cholelithiasis (LPAC) is associated with variants of the adenosine triphosphate-binding cassette subfamily B, member 4 (ABCB4) gene and is characterized by reduced phosphatidylcholine secretion into bile, impairing the formation of micelles and thus exposing bile ducts to toxic bile acids and increasing cholesterol saturation. LPAC is present in 1% of patients with gallstones and post-cholecystectomy pain is common in this group. LPAC is an under-appreciated cause of post-cholecystectomy pain. The aim of this study is to assess a cohort of patients with post-cholecystectomy pain to identify those with clinical features suggesting that further investigations for LPAC would be beneficial. METHODS: A retrospective chart review was performed of the first 2 years of post-operative follow-up for all patients under 40 years of age undergoing cholecystectomy for symptomatic gallstones at a tertiary centre between January 2016 and December 2017. RESULTS: 258 patients under the age of 40 underwent a cholecystectomy. 50 patients (19.4%) reported abdominal pain post-cholecystectomy. Five patients (1.9%) fulfilled the criteria for suspected LPAC. Family history of gallstones was documented in 33 of 258 (12.8%) of cases. Obstetric history was obtained in 69 of 197 (35%) female patients. None of the five patients identified above who satisfied the criteria of LPAC had the diagnosis of LPAC considered by their treating clinicians. CONCLUSION: LPAC is an under-recognized cause of post-cholecystectomy pain. Treatment can avoid long-term symptoms and complications. Clinicians should take a family history and obstetric history to alert them to the diagnosis of LPAC.

Role of microRNA-23b in flow-regulation of Rb phosphorylation and endothelial cell growth.

MicroRNAs (miRs) can regulate many cellular functions, but their roles in regulating responses of vascular endothelial cells (ECs) to mechanical stimuli remain unexplored. We hypothesize that the physiological responses of ECs are regulated by not only mRNA and protein signaling networks, but also expression of the corresponding miRs. EC growth arrest induced by pulsatile shear (PS) flow is an important feature for flow regulation of ECs. miR profiling showed that 21 miRs are differentially expressed (8 up- and 13 downregulated) in response to 24-h PS as compared to static condition (ST). The mRNA expression profile indicates EC growth arrest under 24-h PS. Analysis of differentially expressed miRs yielded 68 predicted mRNA targets that overlapped with results of microarray mRNA profiling. Functional analysis of miR profile indicates that the cell cycle network is highly regulated. The upregulation of miR-23b and miR-27b was found to correlate with the PS-induced EC growth arrest. Inhibition of miR-23b using antagomir-23b oligonucleotide (AM23b) reversed the PS-induced E2F1 reduction and retinoblastoma (Rb) hypophosphorylation and attenuated the PS-induced G1/G0 arrest. Antagomir AM27b regulated E2F1 expression, but did not affect Rb and growth arrest. Our findings indicate that PS suppresses EC proliferation through the regulation of miR-23b and provide insights into the role of miRs in mechanotransduction.

Targeted liver ultrasound performed by an expert is the pivotal imaging examination for low phospholipid-associated cholelithiasis.

OBJECTIVES: Low phospholipid-associatedcholelithiasis (LPAC) is a clinical syndrome that can be associated with variants in the adenosinetriphosphate-binding cassette subfamily B, member 4 (ABCB4) transporter gene, in a proportion of patients. The diagnosis of LPAC is defined by clinical as well as imaging criteria of intrahepatic hyperechoic foci or microlithiasis and biliary sludge on ultrasound. The aim of the study was to assess the role of imaging in investigating patients presenting with clinical features suggesting a diagnosis of LPAC. METHODS: Imaging findings in 51 patients with clinical LPAC were retrospectively reviewed. Most patients had been referred with difficult-to-manage biliary pain postcholecystectomy and some with intrahepatic dilated ducts and stones. The diagnosis of LPAC was made on clinical features. RESULTS: The patients were young with symptom onset at median age 24 years and were mainly female (75%). Ultrasound was performed by an expert in 48/51 and magnetic resonance cholangiopancreatography (MRCP) in 47/51 patients. Targeted liver ultrasound found small hyperechoic foci with comet tail artifacts or posterior acoustic shadowing typical of LPAC in 30/48 (63%) of examinations. However, ultrasound examinations performed before referral for investigation did not report these findings. Intrahepatic duct dilatation was seen in 26/51 (51%) of cases. MRCP did not reliably detect microlithiasis. CONCLUSIONS: Targeted liver ultrasound performed by an expert aware of the possible diagnosis is the pivotal investigation for patients with clinical features suggesting LPAC. The findings in ultrasound performed before referral suggest LPAC is under-recognized and under-diagnosed.

Biochemical resolving power of fluorescence lifetime imaging: untangling the roles of the instrument response function and photon-statistics.

A deeper understanding of spatial resolution has led to innovations in microscopy and the disruption of biomedical research, as with super-resolution microscopy. To foster similar advances in time-resolved and spectral imaging, we have previously introduced the concept of 'biochemical resolving power' in fluorescence microscopy. Here, we apply those concepts to investigate how the instrument response function (IRF), sampling conditions, and photon-statistics limit the biochemical resolution of fluorescence lifetime microscopy. Using Fisher information analysis and Monte Carlo simulations, we reveal the complex dependencies between photon-statistics and the IRF, permitting us to quantify resolution limits that have been poorly understood (e.g., the minimum resolvable decay time for a given width of the IRF and photon-statistics) or previously underappreciated (e.g., optimization of the IRF for biochemical detection). With this work, we unravel common misunderstandings on the role of the IRF and provide theoretical insights with significant practical implications on the design and use of time-resolved instrumentation.

Review article: investigation and management of internal fistulae in Crohn's disease.

BACKGROUND: Crohn's disease is an inflammatory, penetrating intestinal disease associated with fistula formation. Fistulae in Crohn's disease can be classified into external and internal fistulae. Internal fistulae form between the gastrointestinal tract and another internal organ and include enteroenteric, enterocolic, enterovesical and rectovaginal fistulae. They are associated with significant morbidity and a decreased quality of life. AIM: To review the classification, diagnosis, medical and surgical management of internal fistulae in Crohn's disease, and propose a treatment algorithm. METHODS: A literature review on internal fistulae in Crohn's disease in the adult population was undertaken, synthesised and summarised. RESULTS: Internal fistulae occur in up to 15% of patients with Crohn's disease. Multi-modal assessment including a combination of endoscopy and cross-sectional imaging, usually magnetic resonance, is required to diagnose fistulae and determine extent of disease. Determining optimal treatment strategies for these complex fistulae remains a challenge due to limited and generally low-quality data. Most studies to date have focussed on luminal disease, with (usually post hoc) outcomes more often reported for external fistulae, particularly perianal fistulae, than internal fistulae. Anti-tumour necrosis factor therapies have emerged as the mainstay of medical therapy, with particularly promising data for enterovesical fistulae, but many patients will still require surgical intervention. The indications and optimal timing of surgery vs medical therapy remains uncertain; thus multi-disciplinary input when making such decisions is important. CONCLUSIONS: Internal fistulae result in significantly increased morbidity in Crohn's disease, and further studies to determine optimal multi-modality management strategies incorporating medical and surgical therapy are required.

Fast single-cell biochemistry: theory, open source microscopy and applications.

Fluorescence lifetime sensing enables researchers to probe the physicochemical environment of a fluorophore providing a window through which we can observe the complex molecular make-up of the cell. Fluorescence lifetime imaging microscopy (FLIM) quantifies and maps cell biochemistry, a complex ensemble of dynamic processes. Unfortunately, typical high-resolution FLIM systems exhibit rather limited acquisition speeds, often insufficient to capture the time evolution of biochemical processes in living cells. Here, we describe the theoretical background that justifies the developments of high-speed single photon counting systems. We show that systems with low dead-times not only result in faster acquisition throughputs but also improved dynamic range and spatial resolution. We also share the implementation of hardware and software as an open platform, show applications of fast FLIM biochemical imaging on living cells and discuss strategies to balance precision and accuracy in FLIM. The recent innovations and commercialisation of fast time-domain FLIM systems are likely to popularise FLIM within the biomedical community, to impact biomedical research positively and to foster the adoption of other FLIM techniques as well. While supporting and indeed pursuing these developments, with this work we also aim to warn the community about the possible shortcomings of fast single photon counting techniques and to highlight strategies to acquire data of high quality.

Massive hemoptysis managed by rescue extracorporeal membrane oxygenation.

Massive hemoptysis can have a rapid and potentially fatal clinical course. A 68-year-old woman presented with recurrent hemoptysis complicated by refractory hypoxemia and shock despite aggressive intervention. The use of veno-venous extracorporeal membrane oxygenation was a nontraditional intervention that ultimately proved to be lifesaving, but is by no means recommended for routine use in this setting.

Tracking Functional Tumor Cell Subpopulations of Malignant Glioma by Phasor Fluorescence Lifetime Imaging Microscopy of NADH.

Intra-tumoral heterogeneity is associated with therapeutic resistance of cancer and there exists a need to non-invasively identify functional tumor subpopulations responsible for tumor recurrence. Reduced nicotinamide adenine dinucleotide (NADH) is a metabolic coenzyme essential in cellular respiration. Fluorescence lifetime imaging microscopy (FLIM) of NADH has been demonstrated to be a powerful label-free indicator for inferring metabolic states of living cells. Using FLIM, we identified a significant shift towards longer NADH fluorescence lifetimes, suggesting an increase in the fraction of protein-bound NADH, in the invasive stem-like tumor-initiating cell (STIC) subpopulation relative to the tumor mass-forming cell (TMC) subpopulation of malignant gliomas. By applying our previously studied model to transition glioma from a majority of STIC to a majority of TMC in serum-adherent culture conditions following serial passages, we compared changes in NADH states, cellular respirations (oxidative phosphorylation and glycolysis), EGFR expression, and cell-growth speed over passages. We identified a significant positive correlation between free-NADH fraction and cell growth, which was related to an increase of TMC fraction. In comparison, the increase of EGFR and cellular respirations preceded all these changes. In conclusion, FLIM of NADH provides a non-invasive method to monitor the dynamics of tumor heterogeneity before and after treatment.

Spatial analysis of Cdc42 activity reveals a role for plasma membrane-associated Cdc42 in centrosome regulation.

The ability of the small GTPase Cdc42 to regulate diverse cellular processes depends on tight spatial control of its activity. Cdc42 function is best understood at the plasma membrane (PM), where it regulates cytoskeletal organization and cell polarization. Active Cdc42 has also been detected at the Golgi, but its role and regulation at this organelle are only partially understood. Here we analyze the spatial distribution of Cdc42 activity by moni-toring the dynamics of the Cdc42 FLARE biosensor using the phasor approach to FLIM-FRET. Phasor analysis revealed that Cdc42 is active at all Golgi cisternae and that this activity is controlled by Tuba and ARHGAP10, two Golgi-associated Cdc42 regulators. To our surprise, FGD1, another Cdc42 GEF at the Golgi, was not required for Cdc42 regulation at the Golgi, although its depletion decreased Cdc42 activity at the PM. Similarly, changes in Golgi morphology did not affect Cdc42 activity at the Golgi but were associated with a substantial reduction in PM-associated Cdc42 activity. Of interest, cells with reduced Cdc42 activity at the PM displayed altered centrosome morphology, suggesting that centrosome regulation may be mediated by active Cdc42 at the PM. Our study describes a novel quantitative approach to determine Cdc42 activity at specific subcellular locations and reveals new regulatory principles and functions of this small GTPase.

Recapitulating the human tumor microenvironment: Colon tumor-derived extracellular matrix promotes angiogenesis and tumor cell growth.

Extracellular matrix (ECM) is an essential and dynamic component of all tissues and directly affects cellular behavior by providing both mechanical and biochemical signaling cues. Changes in ECM can alter tissue homeostasis, potentially leading to promotion of cellular transformation and the generation of tumors. Therefore, understanding ECM compositional changes during cancer progression is vital to the development of targeted treatments. Previous efforts to reproduce the native 3D cellular microenvironment have utilized protein gels and scaffolds that incompletely recapitulate the complexity of native tissues. Here, we address this problem by extracting and comparing ECM from normal human colon and colon tumor that had metastasized to liver. We found differences in protein composition and stiffness, and observed significant differences in vascular network formation and tumor growth in each of the reconstituted matrices, both in vitro and in vivo. We studied free/bound ratios of NADH in the tumor and endothelial cells using Fluorescence Lifetime Imaging Microscopy as a surrogate for the metabolic state of the cells. We observed that cells seeded in tumor ECM had higher relative levels of free NADH, consistent with a higher glycolytic rate, than those seeded in normal ECM. These results demonstrate that the ECM plays an important role in the growth of cancer cells and their associated vasculature.

Physical activity and 3-year BMI change in overweight and obese children.

OBJECTIVES: Targeting physical activity (PA) is a mainstay in obesity treatment, but its BMI benefits are poorly quantified. We studied long-term predictive PA-BMI relationships in overweight/obese children presenting to primary care. METHODS: Three-year follow-up of 182 overweight/obese 5- to 10-year-olds recruited from 45 Melbourne general practices. PREDICTOR: 7-day accelerometry (counts per minute, cpm). OUTCOMES: change in BMI z score, BMI category, and clinically significant BMI improvement (z score change ≥0.5). ANALYSIS: Linear and logistic regression. RESULTS: Mean (SD) baseline and 3-year BMI z scores were 1.8 (0.6) and 1.8 (0.7), and mean (SD) activity scores 334 (111) and 284 (104) cpm, respectively. Baseline activity did not predict BMI change. However, for every 100 cpm increase in change in activity over 3 years, BMI z score fell by 0.11 (95% confidence interval [CI] 0.03-0.20; P = .006). There were also trends toward greater odds of staying in the same, versus moving to a higher, BMI category (odds ratio 1.85, 95% CI 0.99-3.46) and clinically significant BMI improvement (odds ratio 1.96, 95% CI 0.90-4.27; P = .09). Change in percentage time spent in moderate-vigorous (P = .01), but not sedentary (P = .39) or light (P = .59), activity predicted reduced BMI z score. CONCLUSIONS: Sustained increase in moderate-vigorous PA predicts reducing BMI z score over 3 years in overweight/obese children presenting to primary care. However, the small BMI change associated with even the largest activity changes may explain disappointing BMI outcomes of brief primary care interventions targeting PA.