Nonlinear mechanics of human mitotic chromosomes.

In preparation for mitotic cell division, the nuclear DNA of human cells is compacted into individualized, X-shaped chromosomes1. This metamorphosis is driven mainly by the combined action of condensins and topoisomerase IIα (TOP2A)2,3, and has been observed using microscopy for over a century. Nevertheless, very little is known about the structural organization of a mitotic chromosome. Here we introduce a workflow to interrogate the organization of human chromosomes based on optical trapping and manipulation. This allows high-resolution force measurements and fluorescence visualization of native metaphase chromosomes to be conducted under tightly controlled experimental conditions. We have used this method to extensively characterize chromosome mechanics and structure. Notably, we find that under increasing mechanical load, chromosomes exhibit nonlinear stiffening behaviour, distinct from that predicted by classical polymer models4. To explain this anomalous stiffening, we introduce a hierarchical worm-like chain model that describes the chromosome as a heterogeneous assembly of nonlinear worm-like chains. Moreover, through inducible degradation of TOP2A5 specifically in mitosis, we provide evidence that TOP2A has a role in the preservation of chromosome compaction. The methods described here open the door to a wide array of investigations into the structure and dynamics of both normal and disease-associated chromosomes.

Standard of Care Versus Octreotide in Angiodysplasia-Related Bleeding (the OCEAN Study): A Multicenter Randomized Controlled Trial.

BACKGROUND & AIMS: Gastrointestinal angiodysplasias are vascular anomalies that may result in transfusion-dependent anemia despite endoscopic therapy. An individual patient data meta-analysis of cohort studies suggests that octreotide decreases rebleeding rates, but component studies possessed a high risk of bias. We investigated the efficacy of octreotide in reducing the transfusion requirements of patients with angiodysplasia-related anemia in a clinical trial setting. METHODS: The study was designed as a multicenter, open-label, randomized controlled trial. Patients with angiodysplasia bleeding were required to have had at least 4 red blood cell (RBC) units or parental iron infusions, or both, in the year preceding randomization. Patients were allocated (1:1) to 40-mg octreotide long-acting release intramuscular every 28 days or standard of care, including endoscopic therapy. The treatment duration was 1 year. The primary outcome was the mean difference in the number of transfusion units (RBC + parental iron) between the octreotide and standard of care groups. Patients who received at least 1 octreotide injection or followed standard of care for at least 1 month were included in the intention-to-treat analyses. Analyses of covariance were used to adjust for baseline transfusion requirements and incomplete follow-up. RESULTS: We enrolled 62 patients (mean age, 72 years; 32 men) from 17 Dutch hospitals in the octreotide (n = 31) and standard of care (n = 31) groups. Patients required a mean number of 20.3 (standard deviation, 15.6) transfusion units and 2.4 (standard deviation, 2.0) endoscopic procedures in the year before enrollment. The total number of transfusions was lower with octreotide (11.0; 95% confidence interval [CI], 5.5-16.5) compared with standard of care (21.2; 95% CI, 15.7-26.7). Octreotide reduced the mean number of transfusion units by 10.2 (95% CI, 2.4-18.1; P = .012). Octreotide reduced the annual volume of endoscopic procedures by 0.9 (95% CI, 0.3-1.5). CONCLUSIONS: Octreotide effectively reduces transfusion requirements and the need for endoscopic therapy in patients with angiodysplasia-related anemia. CLINICALTRIALS: gov, NCT02384122.

Ion-mediated condensation controls the mechanics of mitotic chromosomes.

During mitosis in eukaryotic cells, mechanical forces generated by the mitotic spindle pull the sister chromatids into the nascent daughter cells. How do mitotic chromosomes achieve the necessary mechanical stiffness and stability to maintain their integrity under these forces? Here we use optical tweezers to show that ions involved in physiological chromosome condensation are crucial for chromosomal stability, stiffness and viscous dissipation. We combine these experiments with high-salt histone depletion and theory to show that chromosomal elasticity originates from the chromatin fibre behaving as a flexible polymer, whereas energy dissipation can be explained by modelling chromatin loops as an entangled polymer solution. Taken together, we show how collective properties of mitotic chromosomes, a biomaterial of incredible complexity, emerge from molecular properties, and how they are controlled by the physico-chemical environment.

Regulation of T7 gp2.5 binding dynamics by its C-terminal tail, template conformation and sequence.

Bacteriophage T7 single-stranded DNA-binding protein (gp2.5) binds to and protects transiently exposed regions of single-stranded DNA (ssDNA) while dynamically interacting with other proteins of the replication complex. We directly visualize fluorescently labelled T7 gp2.5 binding to ssDNA at the single-molecule level. Upon binding, T7 gp2.5 reduces the contour length of ssDNA by stacking nucleotides in a force-dependent manner, suggesting T7 gp2.5 suppresses the formation of secondary structure. Next, we investigate the binding dynamics of T7 gp2.5 and a deletion mutant lacking 21 C-terminal residues (gp2.5-Δ21C) under various template tensions. Our results show that the base sequence of the DNA molecule, ssDNA conformation induced by template tension, and the acidic terminal domain from T7 gp2.5 significantly impact on the DNA binding parameters of T7 gp2.5. Moreover, we uncover a unique template-catalyzed recycling behaviour of T7 gp2.5, resulting in an apparent cooperative binding to ssDNA, facilitating efficient spatial redistribution of T7 gp2.5 during the synthesis of successive Okazaki fragments. Overall, our findings reveal an efficient binding mechanism that prevents the formation of secondary structures by enabling T7 gp2.5 to rapidly rebind to nearby exposed ssDNA regions, during lagging strand DNA synthesis.

Development and validation of a machine learning-based, point-of-care risk calculator for post-ERCP pancreatitis and prophylaxis selection.

BACKGROUND AND AIMS: A robust model of post-ERCP pancreatitis (PEP) risk is not currently available. We aimed to develop a machine learning-based tool for PEP risk prediction to aid in clinical decision making related to periprocedural prophylaxis selection and postprocedural monitoring. METHODS: Feature selection, model training, and validation were performed using patient-level data from 12 randomized controlled trials. A gradient-boosted machine (GBM) model was trained to estimate PEP risk, and the performance of the resulting model was evaluated using the area under the receiver operating curve (AUC) with 5-fold cross-validation. A web-based clinical decision-making tool was created, and a prospective pilot study was performed using data from ERCPs performed at the Johns Hopkins Hospital over a 1-month period. RESULTS: A total of 7389 patients were included in the GBM with an 8.6% rate of PEP. The model was trained on 20 PEP risk factors and 5 prophylactic interventions (rectal nonsteroidal anti-inflammatory drugs [NSAIDs], aggressive hydration, combined rectal NSAIDs and aggressive hydration, pancreatic duct stenting, and combined rectal NSAIDs and pancreatic duct stenting). The resulting GBM model had an AUC of 0.70 (65% specificity, 65% sensitivity, 95% negative predictive value, and 15% positive predictive value). A total of 135 patients were included in the prospective pilot study, resulting in an AUC of 0.74. CONCLUSIONS: This study demonstrates the feasibility and utility of a novel machine learning-based PEP risk estimation tool with high negative predictive value to aid in prophylaxis selection and identify patients at low risk who may not require extended postprocedure monitoring.

Ferumoxtran-10-enhanced MRI for pre-operative metastatic lymph node detection in pancreatic, duodenal, or periampullary adenocarcinoma.

OBJECTIVES: To assess 3-Tesla (3-T) ultra-small superparamagnetic iron oxide (USPIO)-enhanced MRI in detecting lymph node (LN) metastases for resectable adenocarcinomas of the pancreas, duodenum, or periampullary region in a node-to-node validation against histopathology. METHODS: Twenty-seven consecutive patients with a resectable pancreatic, duodenal, or periampullary adenocarcinoma were enrolled in this prospective single expert centre study. Ferumoxtran-10-enhanced 3-T MRI was performed pre-surgery. LNs found on MRI were scored for suspicion of metastasis by two expert radiologists using a dedicated scoring system. Node-to-node matching from in vivo MRI to histopathology was performed using a post-operative ex vivo 7-T MRI of the resection specimen. Sensitivity and specificity were calculated using crosstabs. RESULTS: Eighteen out of 27 patients (median age 65 years, 11 men) were included in the final analysis (pre-surgery withdrawal n = 4, not resected because of unexpected metastases peroperatively n = 2, and excluded because of inadequate contrast-agent uptake n = 3). On MRI 453 LNs with a median size of 4.0 mm were detected, of which 58 (13%) were classified as suspicious. At histopathology 385 LNs with a median size of 5.0 mm were found, of which 45 (12%) were metastatic. For 55 LNs node-to-node matching was possible. Analysis of these 55 matched LNs, resulted in a sensitivity and specificity of 83% (95% CI: 36-100%) and 92% (95% CI: 80-98%), respectively. CONCLUSION: USPIO-enhanced MRI is a promising technique to preoperatively detect and localise LN metastases in patients with pancreatic, duodenal, or periampullary adenocarcinoma. CLINICAL RELEVANCE STATEMENT: Detection of (distant) LN metastases with USPIO-enhanced MRI could be used to determine a personalised treatment strategy that could involve neoadjuvant or palliative chemotherapy, guided resection of distant LNs, or targeted radiotherapy. REGISTRATION: The study was registered on clinicaltrials.gov NCT04311047. https://clinicaltrials.gov/ct2/show/NCT04311047?term=lymph+node&cond=Pancreatic+Cancer&cntry=NL&draw=2&rank=1 . KEY POINTS: LN metastases of pancreatic, duodenal, or periampullary adenocarcinoma cannot be reliably detected with current imaging. This technique detected LN metastases with a sensitivity and specificity of 83% and 92%, respectively. MRI with ferumoxtran-10 is a promising technique to improve preoperative staging in these cancers.

Direct imaging of intraflagellar-transport turnarounds reveals that motors detach, diffuse, and reattach to opposite-direction trains.

Intraflagellar transport (IFT), a bidirectional intracellular transport mechanism in cilia, relies on the cooperation of kinesin-2 and IFT-dynein motors. In Caenorhabditis elegans chemosensory cilia, motors undergo rapid turnarounds to effectively work together in driving IFT. Here, we push the envelope of fluorescence imaging to obtain insight into the underlying mechanism of motor turnarounds. We developed an alternating dual-color imaging system that allows simultaneous single-molecule imaging of kinesin-II turnarounds and ensemble imaging of IFT trains. This approach allowed direct visualization of motor detachment and reattachment during turnarounds and accordingly demonstrated that the turnarounds are actually single-motor switching between opposite-direction IFT trains rather than the behaviors of motors moving independently of IFT trains. We further improved the time resolution of single-motor imaging up to 30 ms to zoom into motor turnarounds, revealing diffusion during motor turnarounds, which unveils the mechanism of motor switching trains: detach-diffuse-attach. The subsequent single-molecule analysis of turnarounds unveiled location-dependent diffusion coefficients and diffusion times for both kinesin-2 and IFT-dynein motors. From correlating the diffusion times with IFT train frequencies, we estimated that kinesins tend to attach to the next train passing in the opposite direction. IFT-dynein, however, diffuses longer and lets one or two trains pass before attaching. This might be a direct consequence of the lower diffusion coefficient of the larger IFT-dynein. Our results provide important insights into how motors can cooperate to drive intracellular transport.

Short-term and Long-term Outcomes of a Disruption and Disconnection of the Pancreatic Duct in Necrotizing Pancreatitis: A Multicenter Cohort Study in 896 Patients.

INTRODUCTION: Necrotizing pancreatitis may result in a disrupted or disconnected pancreatic duct (DPD) with the potential for long-lasting negative impact on a patient's clinical outcome. There is a lack of detailed data on the full clinical spectrum of DPD, which is critical for the development of better diagnostic and treatment strategies. METHODS: We performed a long-term post hoc analysis of a prospectively collected nationwide cohort of 896 patients with necrotizing pancreatitis (2005-2015). The median follow-up after hospital admission was 75 months (P25-P75: 41-151). Clinical outcomes of patients with and without DPD were compared using regression analyses, adjusted for potential confounders. Predictive features for DPD were explored. RESULTS: DPD was confirmed in 243 (27%) of the 896 patients and resulted in worse clinical outcomes during both the patient's initial admission and follow-up. During hospital admission, DPD was associated with an increased rate of new-onset intensive care unit admission (adjusted odds ratio [aOR] 2.52; 95% confidence interval [CI] 1.62-3.93), new-onset organ failure (aOR 2.26; 95% CI 1.45-3.55), infected necrosis (aOR 4.63; 95% CI 2.87-7.64), and pancreatic interventions (aOR 7.55; 95% CI 4.23-13.96). During long-term follow-up, DPD increased the risk of pancreatic intervention (aOR 9.71; 95% CI 5.37-18.30), recurrent pancreatitis (aOR 2.08; 95% CI 1.32-3.29), chronic pancreatitis (aOR 2.73; 95% CI 1.47-5.15), and endocrine pancreatic insufficiency (aOR 1.63; 95% CI 1.05-2.53). Central or subtotal pancreatic necrosis on computed tomography (OR 9.49; 95% CI 6.31-14.29) and a high level of serum C-reactive protein in the first 48 hours after admission (per 10-point increase, OR 1.02; 95% CI 1.00-1.03) were identified as independent predictors for developing DPD. DISCUSSION: At least 1 of every 4 patients with necrotizing pancreatitis experience DPD, which is associated with detrimental, short-term and long-term interventions, and complications. Central and subtotal pancreatic necrosis and high levels of serum C-reactive protein in the first 48 hours are independent predictors for DPD.

Low-Field Actuating Magnetic Elastomer Membranes Characterized using Fibre-Optic Interferometry.

Smart robotic devices remotely powered by magnetic field have emerged as versatile tools for wide biomedical applications. Soft magnetic elastomer (ME) composite membranes with high flexibility and responsiveness are frequently incorporated to enable local actuation for wireless sensing or cargo delivery. However, the fabrication of thin ME membranes with good control in geometry and uniformity remains challenging, as well as the optimization of their actuating performances under low fields (milli-Tesla). In this work, the development of ME membranes comprising of low-cost magnetic powder and highly soft elastomer through a simple template-assisted doctor blading approach, is reported. The fabricated ME membranes are controllable in size (up to centimetre-scale), thickness (tens of microns) and high particle loading (up to 70 wt.%). Conflicting trade-off effects of particle concentration upon magnetic responsiveness and mechanical stiffness are investigated and found to be balanced off as it exceeds 60 wt.%. A highly sensitive fibre-optic interferometric sensing system and a customized fibre-ferrule-membrane probe are first proposed to enable dynamic actuation and real-time displacement characterization. Free-standing ME membranes are magnetically excited under low field down to 2 mT, and optically monitored with nanometer accuracy. The fast and consistent responses of ME membranes showcase their promising biomedical applications in nanoscale actuation and sensing.

Prospective multicentre study of indications for surgery in patients with idiopathic acute pancreatitis following endoscopic ultrasonography (PICUS).

BACKGROUND: Cholecystectomy in patients with idiopathic acute pancreatitis (IAP) is controversial. A randomized trial found cholecystectomy to reduce the recurrence rate of IAP but did not include preoperative endoscopic ultrasonography (EUS). As EUS is effective in detecting gallstone disease, cholecystectomy may be indicated only in patients with gallstone disease. This study aimed to determine the diagnostic value of EUS in patients with IAP, and the rate of recurrent pancreatitis in patients in whom EUS could not determine the aetiology (EUS-negative IAP). METHODS: This prospective multicentre cohort study included patients with a first episode of IAP who underwent outpatient EUS. The primary outcome was detection of aetiology by EUS. Secondary outcomes included adverse events after EUS, recurrence of pancreatitis, and quality of life during 1-year follow-up. RESULTS: After screening 957 consecutive patients with acute pancreatitis from 24 centres, 105 patients with IAP were included and underwent EUS. In 34 patients (32 per cent), EUS detected an aetiology: (micro)lithiasis and biliary sludge (23.8 per cent), chronic pancreatitis (6.7 per cent), and neoplasms (2.9 per cent); 2 of the latter patients underwent pancreatoduodenectomy. During 1-year follow-up, the pancreatitis recurrence rate was 17 per cent (12 of 71) among patients with EUS-negative IAP versus 6 per cent (2 of 34) among those with positive EUS. Recurrent pancreatitis was associated with poorer quality of life. CONCLUSION: EUS detected an aetiology in a one-third of patients with a first episode of IAP, requiring mostly cholecystectomy or pancreatoduodenectomy. The role of cholecystectomy in patients with EUS-negative IAP remains uncertain and warrants further study.

Some patients develop acute inflammation of the pancreas without a clear cause. These patients have a high risk of developing more episodes of acute inflammation of the pancreas. Potentially, such inflammation could be caused by tiny gallstones that physicians are not able to detect. If this is true, these patients may also benefit from surgical removal of the gallbladder. However, this is still controversial. Endoscopic ultrasonography is a diagnostic procedure during which a physician looks at the gallbladder and bile ducts in detail via a small ultrasound probe inserted through the mouth. This endoscopic ultrasonography may be able to detect gallstones better than physicians were able to previously. This study tested the value of endoscopic ultrasonography, and the number of patients who developed more episodes of acute inflammation after endoscopic ultrasonography was recorded. Some 106 patients with acute inflammation of the pancreas for the first time without a clear cause participated and were offered endoscopic ultrasonography. The number of times endoscopic ultrasonography found a cause for the acute inflammation was recorded, as well as safety parameters, number of patients who developed more episodes of acute inflammation, and quality of life. After screening 957 patients, 105 ultimately underwent endoscopic ultrasonography. A cause was found in one-third of patients. This was mostly (tiny) gallstones, but chronic inflammation and even tumours were found. These patients were mostly treated surgically for their gallstones and tumours. In the first year after the first acute episode of inflammation, the inflammation came back at least once in almost one in six patients in whom endoscopic ultrasonography did not find a cause. This occurred less in patients in whom a cause was found; the inflammation came back in 1 in 16 of these patients. It was also found that having inflammation coming back negatively affected quality of life. In this study, endoscopic ultrasonography was able to detect a cause in one-third of patients with first-time acute inflammation of the pancreas. In one in four patients, this cause could be treated by a surgical procedure. Whether surgical removal of the gallbladder can be helpful in patients in whom endoscopic ultrasonography is not able to detect an aetiology should be investigated in further studies.

Fiber-optic hydrophone for detection of high-intensity ultrasound waves.

Fiber-optic hydrophones (FOHs) are widely used to detect high-intensity focused ultrasound (HIFU) fields. The most common type consists of an uncoated single-mode fiber with a perpendicularly cleaved end face. The main disadvantage of these hydrophones is their low signal-to-noise ratio (SNR). To increase the SNR, signal averaging is performed, but the associated increased acquisition times hinder ultrasound field scans. In this study, with a view to increasing SNR while withstanding HIFU pressures, the bare FOH paradigm is extended to include a partially reflective coating on the fiber end face. Here, a numerical model based on the general transfer-matrix method was implemented. Based on the simulation results, a single-layer, 172 nm TiO2-coated FOH was fabricated. The frequency range of the hydrophone was verified from 1 to 30 MHz. The SNR of the acoustic measurement with the coated sensor was 21 dB higher than that of the uncoated one. The coated sensor successfully withstood a peak positive pressure of 35 MPa for 6000 pulses.

Suspected common bile duct stones: reduction of unnecessary ERCP by pre-procedural imaging and timing of ERCP.

BACKGROUND: Endoscopic retrograde cholangiopancreatography (ERCP) is the procedure of choice to remove sludge/stones from the common bile duct (CBD). In a small but clinically important proportion of patients with suspected choledocholithiasis ERCP is negative. This is undesirable because of ERCP associated morbidity. We aimed to map the diagnostic pathway leading up to ERCP and evaluate ERCP outcome. METHODS: We established a prospective multicenter cohort of patients with suspected CBD stones. We assessed the determinants that were associated with CBD sludge or stone detection upon ERCP. RESULTS: We established a cohort of 707 patients with suspected CBD sludge or stones (62% female, median age 59 years). ERCP was negative for CBD sludge or stones in 155 patients (22%). Patients with positive ERCPs frequently had pre-procedural endoscopic ultrasonography (EUS) or magnetic resonance cholangiopancreatography (MRCP) imaging (44% vs. 35%; P = 0.045). The likelihood of ERCP sludge and stones detection was higher when the time interval between EUS or MRCP and ERCP was less than 2 days (odds ratio 2.35; 95% CI 1.25-4.44; P = 0.008; number needed to harm 7.7). CONCLUSIONS: Even in the current era of society guidelines and use of advanced imaging CBD sludge or stones are absent in one out of five ERCPs performed for suspected CBD stones. The proportion of unnecessary ERCPs is lower in case of pre-procedural EUS or MRCP. A shorter time interval between EUS or MRCP increases the yield of ERCP for suspected CBD stones and should, therefore, preferably be performed within 2 days before ERCP.

Turnover of the extracellular polymeric matrix of granules performing biological phosphate removal.

Polyphosphate accumulating organisms (PAOs) are responsible for enhanced biological phosphate removal (EBPR) from wastewater, where they grow embedded in a matrix of extracellular polymeric substances (EPS). EPSs comprise a mixture of biopolymers like polysaccharides or (glyco)proteins. Despite previous studies, little is known about the dynamics of EPS in mixed cultures, and their production by PAOs and potential consumption by flanking microbes. EPSs are biodegradable and have been suggested to be a substrate for other organisms in the community. Studying EPS turnover can help elucidate their biosynthesis and biodegradation cycles. We analyzed the turnover of proteins and polysaccharides in the EPS of an enrichment culture of PAOs relative to the turnover of internal proteins. An anaerobic-aerobic sequencing batch reactor (SBR) simulating EBPR conditions was operated to enrich for PAOs. After achieving a stable culture, carbon source was switched to uniformly 13C-labeled acetate. Samples were collected at the end of each aerobic phase. EPSs were extracted by alkaline treatment. 13C enrichment in proteins and sugars (after hydrolysis of polysaccharides) in the extracted EPS were measured by mass spectrometry. The average turnover rate of sugars and proteins (0.167 and 0.192 d-1 respectively) was higher than the expected value based on the solid removal rate (0.132 d-1), and no significant difference was observed between intracellular and extracellular proteins. This indicates that EPS from the PAO enriched community is not selectively degraded by flanking populations under stable EBPR process conditions. Instead, we observed general decay of biomass, which corresponds to a value of 0.048 d-1. KEY POINTS: • Proteins showed a higher turnover rate than carbohydrates. • Turnover of EPS was similar to the turnover of intracellular proteins. • EPS is not preferentially consumed by flanking populations.

Unravelling the mechanisms of Type 1A topoisomerases using single-molecule approaches.

Topoisomerases are essential enzymes that regulate DNA topology. Type 1A family topoisomerases are found in nearly all living organisms and are unique in that they require single-stranded (ss)DNA for activity. These enzymes are vital for maintaining supercoiling homeostasis and resolving DNA entanglements generated during DNA replication and repair. While the catalytic cycle of Type 1A topoisomerases has been long-known to involve an enzyme-bridged ssDNA gate that allows strand passage, a deeper mechanistic understanding of these enzymes has only recently begun to emerge. This knowledge has been greatly enhanced through the combination of biochemical studies and increasingly sophisticated single-molecule assays based on magnetic tweezers, optical tweezers, atomic force microscopy and Förster resonance energy transfer. In this review, we discuss how single-molecule assays have advanced our understanding of the gate opening dynamics and strand-passage mechanisms of Type 1A topoisomerases, as well as the interplay of Type 1A topoisomerases with partner proteins, such as RecQ-family helicases. We also highlight how these assays have shed new light on the likely functional roles of Type 1A topoisomerases in vivo and discuss recent developments in single-molecule technologies that could be applied to further enhance our understanding of these essential enzymes.

The Synthesis and Base-Induced Breakdown of Triaryl 1,4-Oxathiins-An Experimental and DFT Study.

1,4-Oxathiins are valued for a breadth of bioactivities and are known commercial fungicides. This article explores a novel preparation of 2,3,6-trisubstituted 1,4-oxathiin-S,S-dioxides via the reaction of benzyl 1-alkynyl sulfones and aryl aldehydes under basic conditions. A total of 20 examples possessing exclusively a trans arrangement of the 2,3-diaryl substituents are exhibited; the products demonstrate a variation of functional groups on the aryl ring attached to the heterocyclic ring system. The preparation is hindered by the base sensitivity of the products, and a ring-opened by-product typically contaminates the reaction mixture. A DFT assessment of the overall system includes a lithium counterion and offers possible pathways for the incorporation of the aldehyde, the cyclization step and the requisite proton transfers. In addition, the DFT work reveals options for the ring opening chemistry. It appears the trans 2,3-diaryl selectivity is set during the cyclization stage of the reaction sequence. The practical work uncovers a new reaction pathway to create a family of novel 1,4-oxathiin-S,S-dioxides whereas the computational work offers an understanding of the structures and possible mechanisms involved.

A study protocol to develop and test an e-health intervention in follow-up service for intensive care survivors' relatives.

BACKGROUND: The negative impact on long-term health-related outcomes among relatives of critically ill patients in the intensive care unit (ICU) has been well described. High-quality ICU specialized follow-up care, which is easily accessible with digital innovation and which is designed by and with relevant stakeholders (i.e., ICU patients' relatives and nurses), should be considered to reduce these impairments in the psychological and social domains. AIM: The programme's aim is to develop and test an e-health intervention in a follow-up service to support ICU patients' relatives. Here, the protocol for the overall study programme will be described. STUDY DESIGN: The overall study comprises a mixed-methods, multicentre research design with qualitative and quantitative study parts. The study population is ICU patients' adult relatives and ICU nurses. The main outcomes are the experiences of these stakeholders with the newly developed e-health intervention. There will be no predefined selection based on age, gender, and level of education to maximize diversity throughout the study programme. After the participants provide informed consent, data will be gathered through focus groups (n = 5) among relatives and individual interviews (n = 20) among nurses exploring the needs and priorities of a digital follow-up service. The findings will be explored further for priority considerations among members of the patient/relative organization (aiming n = 150), which will serve as a basis for digital prototypes of the e-health intervention. Assessment of the intervention will be followed during an iterative process with investigator-developed questionnaires. Finally, symptoms of anxiety and depression will be measured with the 14-item Dutch version of the 'Hospital Anxiety and Depression Scale', and symptoms of posttraumatic stress will be measured with the 21-item Dutch version of the 'Impact of Events Scale-Revised' to indicate the effectiveness of digital support among ICU patients' relatives. RELEVANCE TO CLINICAL PRACTICE: The e-health intervention to be developed during this research programme can possibly bridge the gap in integrated ICU follow-up care by providing relevant information, self-monitoring and stimulating self-care among ICU patients' relatives.

The Role of Clips in Preventing Delayed Bleeding After Colorectal Polyp Resection: An Individual Patient Data Meta-Analysis.

BACKGROUND & AIMS: Nonpedunculated colorectal polyps are normally endoscopically removed to prevent neoplastic progression. Delayed bleeding is the most common major adverse event. Clipping the resection defect has been suggested to reduce delayed bleedings. Our aim was to determine if prophylactic clipping reduces delayed bleedings and to analyze the contribution of polyp characteristics, extent of defect closure, and antithrombotic use. METHODS: An individual patient data meta-analysis was performed. Studies on prophylactic clipping in nonpedunculated colorectal polyps were selected from PubMed, Embase, Web of Science, and Cochrane database (last selection, April 2020). Authors were invited to share original study data. The primary outcome was delayed bleeding ≤30 days. Multivariable mixed models were used to determine the efficacy of prophylactic clipping in various subgroups adjusted for confounders. RESULTS: Data of 5380 patients with 8948 resected polyps were included from 3 randomized controlled trials, 2 prospective, and 8 retrospective studies. Prophylactic clipping reduced delayed bleeding in proximal polyps ≥20 mm (odds ratio [OR], 0.62; 95% confidence interval [CI], 0.44-0.88; number needed to treat = 32), especially with antithrombotics (OR, 0.59; 95% CI, 0.35-0.99; number needed to treat = 23; subgroup of anticoagulants/double platelet inhibitors: n = 226; OR, 0.40; 95% CI, 0.16-1.01; number needed to treat = 12). Prophylactic clipping did not benefit distal polyps ≥20 mm with antithrombotics (OR, 1.41; 95% CI, 0.79-2.52). CONCLUSIONS: Prophylactic clipping reduces delayed bleeding after resection of nonpedunculated, proximal colorectal polyps ≥20 mm, especially in patients using antithrombotics. No benefit was found for distal polyps. Based on this study, patients can be identified who may benefit from prophylactic clipping. (PROSPERO registration number CRD42020104317.).

Diagnosis and treatment of exocrine pancreatic insufficiency in chronic pancreatitis: An international expert survey and case vignette study.

INTRODUCTION: Despite evidence-based guidelines, exocrine pancreatic insufficiency is frequently underdiagnosed and undertreated in patients with chronic pancreatitis. Therefore, the aim of this study is to provide insight into the current opinion and clinical decision-making of international pancreatologists regarding the management of exocrine pancreatic insufficiency. METHODS: An online survey and case vignette study was sent to experts in chronic pancreatitis and members of various pancreatic associations: EPC, E-AHPBA and DPSG. Experts were selected based on publication record from the past 5 years. RESULTS: Overall, 252 pancreatologists participated of whom 44% had ≥ 15 years of experience and 35% treated ≥ 50 patients with chronic pancreatitis per year. Screening for exocrine pancreatic insufficiency as part of the diagnostic work-up for chronic pancreatitis is performed by 69% and repeated annually by 21%. About 74% considers nutritional assessment to be part of the standard work-up. Patients are most frequently screened for deficiencies of calcium (47%), iron (42%), vitamin D (61%) and albumin (59%). In case of clinically steatorrhea, 71% prescribes enzyme supplementation. Of all pancreatologists, 40% refers more than half of their patients to a dietician. Despite existing guidelines, 97% supports the need for more specific and tailored instructions regarding the management of exocrine pancreatic insufficiency. CONCLUSION: This survey identified a lack of consensus and substantial practice variation among international pancreatologists regarding guidelines pertaining the management of exocrine pancreatic insufficiency. These results highlight the need for further adaptation of these guidelines according to current expert opinion and the level of available scientific evidence.

Rectal INdomethacin, oral TacROlimus, or their combination for the prevention of post-ERCP pancreatitis (INTRO Trial): Protocol for a randomized, controlled, double-blinded trial.

BACKGROUND: Acute pancreatitis remains the most common and morbid complication of endoscopic retrograde cholangiopancreatography (ERCP). The use of rectal indomethacin and pancreatic duct stenting has been shown to reduce the incidence and severity of post-ERCP pancreatitis (PEP), but these interventions have limitations. Recent clinical and translational evidence suggests a role for calcineurin inhibitors in the prevention of pancreatitis, with multiple retrospective case series showing a reduction in PEP rates in tacrolimus users. METHODS: The INTRO trial is a multicenter, international, randomized, double-blinded, controlled trial. A total of 4,874 patients undergoing ERCP will be randomized to receive either oral tacrolimus (5 mg) or oral placebo 1-2 h before ERCP, and followed for 30 days post-procedure. Blood and pancreatic aspirate samples will also be collected in a subset of patients to quantify tacrolimus levels. The primary outcome of the study is the incidence of PEP. Secondary endpoints include the severity of PEP, ERCP-related complications, adverse drug events, length of hospital stay, cost-effectiveness, and the pharmacokinetics, pharmacodynamics, and pharmacogenomics of tacrolimus immune modulation in the pancreas. CONCLUSIONS: The INTRO trial will assess the role of calcineurin inhibitors in PEP prophylaxis and develop a foundation for the clinical optimization of this therapeutic strategy from a pharmacologic and economic standpoint. With this clinical trial, we hope to demonstrate a novel approach to PEP prophylaxis using a widely available and well-characterized class of drugs. TRIAL REGISTRATION: NCT05252754, registered on February 14, 2022.