CEACAMS 1, 5, and 6 in disease and cancer: interactions with pathogens.

The CEA family comprises 18 genes and 11 pseudogenes located at chromosome 19q13.2 and is divided into two main groups: cell surface anchored CEA-related cell adhesion molecules (CEACAMs) and the secreted pregnancy-specific glycoproteins (PSGs). CEACAMs are highly glycosylated cell surface anchored, intracellular, and intercellular signaling molecules with diverse functions, from cell differentiation and transformation to modulating immune responses associated with infection, inflammation, and cancer. In this review, we explore current knowledge surrounding CEACAM1, CEACAM5, and CEACAM6, highlight their pathological significance in the areas of cancer biology, immunology, and inflammatory disease, and describe the utility of murine models in exploring questions related to these proteins.

Challenges of developing and executing a multi-site registry for a novel device with evolving indications for use.

BACKGROUND: The introduction of new technologies in endoscopy has been met with uncertainty, skepticism, and lack of standardization or training parameters, particularly when disruptive devices or techniques are involved. The widespread availability of a novel endoscopic suturing device (OverStitch™) for tissue apposition has enabled the development of applications of endoscopic suturing. METHODS: The American Gastroenterological Association partnered with Apollo Endosurgery to develop a registry to capture in a pragmatic non-randomized study the safety, effectiveness, and durability of endoscopic suturing in approximating tissue in the setting of bariatric revision and fixation of endoprosthetic devices. RESULTS: We highlight the challenges of the adoption of novel techniques by examining the process of developing and executing this multicenter registry to assess real-world use of this endoscopic suturing device. We also present our preliminary data on the safety and effectiveness of the novel device as it is applied in the treatment of obesity. CONCLUSIONS: The Prospective Registry for Trans-Orifice Endoscopic Suturing Applications (ES Registry) was an effective Phase 4, postmarketing registry aimed at capturing pragmatic, real-world use of a novel device. These findings serve to solidify the role of endoscopic suturing in clinical practice.

Single session per oral endoscopic myotomy and trans oral incisionless fundoplication - can we prevent reflux in patients with achalasia?

Background and study aims The rate of gastroesophageal reflux disease (GERD) after per oral endoscopic myotomy (POEM) is concerning. Endoscopic anti-reflux methods, such as Trans Oral Incisionless Fundoplication (TIF), are crucial for the long-term success of POEM, especially if they can be performed in the same session. Methods We completed a proof-of-concept canine pilot study (n = 6) to assess safety and feasibility of POEM and TIF in a single session (POEM-TIF). Subsequently, POEM-TIF was also performed in patients with achalasia (n = 5). Herein, we report on the safety, technical and clinical success of the first-in-human cases with symptom follow-up at 1, 3 and 6 months and pH testing at 6 months. Results POEM was completed successfully in six canines (3 anterior and 3 posterior myotomies), followed by TIF in the same session. Necropsy and extensive testing demonstrated no evidence of mucosal injury and no leaks. The reconstructed valve was 220 to 240 degrees, 3 to 4 cm in length, and resulted in concomitant esophageal lengthening (2-5 cm). Using similar principles, the first-in-human cases were performed without intraprocedural or delayed adverse events. pH testing at 6 months showed that four of five patients had no evidence of GERD (DeMeester > 14.72), and in one case, there was evidence of esophagitis. Conclusions Single session POEM-TIF appears to be safe and feasible. Early clinical human data suggests that it may be able to reduce post POEM GERD, however the additional secondary benefits such as lengthening and straightening of the esophagus, may prove to be equally important for the long-term success of POEM.

Remote video auditing in the endoscopy unit for evaluation of duodenoscope reprocessing in a tertiary care center.

BACKGROUND : A significant proportion of duodenoscope-transmitted infections have resulted from errors related to reprocessing. Remote video auditing (RVA) is a tool that can monitor reprocessing compliance but it has not been previously evaluated in a tertiary care setting. The aims of this study were to evaluate: 1) RVA feasibility in a tertiary care setting (defined as the ability to audit every step of duodenoscope reprocessing without delaying the next procedure due to unavailability of duodenoscopes); and 2) the use of RVA as a compliance monitoring tool. METHODS : This was a prospective study at a tertiary care center. A video camera with offsite monitoring was installed in March 2018. Auditors delivered a compliance score after each procedure. The duodenoscope was not used until it passed the audit. Feasibility and compliance data were collected from April 2018 to August 2019 after a 1-month run-in phase. Both per-step compliance and overall 100 % compliance rates were measured. RESULTS : Of 743 duodenoscope reprocessing procedures, 32 666 individual steps were audited and 99.9 % of the steps were fully viewable. The mean time per audit was 38.3 minutes, the mean duodenoscope turnover time was 76.1 minutes, and there were no delays to the next procedure due to unavailability of duodenoscopes. The per-step compliance rate was 99.5 % but the overall 100 % compliance rate was 90.3 %. CONCLUSIONS : The use of RVA in duodenoscope reprocessing was feasible and promoted sustained high-level compliance in a tertiary care center.

Adjunctive Yield of Wide-Area Transepithelial Sampling for Dysplasia Detection After Advanced Imaging and Random Biopsies in Barrett's Esophagus.

INTRODUCTION: Little is known about the additive yield of wide-area transepithelial sampling with computer-assisted three-dimensional analysis (WATS-3D) after a thorough examination with advanced imaging. The aim was to evaluate the adjunctive yield of WATS-3D after advanced imaging. METHODS: This is an observational cohort study from January 2017 to December 2018 for consecutive patients who underwent an examination that consists of high-definition white light endoscopy (HDWLE), narrow-band imaging (NBI), volumetric laser endomicroscopy (VLE), and Seattle protocol (SP) biopsies (collectively termed HDWLE-NBI-VLE-SP examination). Raised lesions were removed by endoscopic resection. Areas suspicious for dysplasia on NBI and VLE were biopsied. This was followed by random biopsies and WATS-3D brush biopsies. RESULTS: One hundred thirty-eight cases were included in this study. Thirty-five cases (25% of the total) were identified as some degree of dysplasia on the HDWLE-NBI-VLE-SP examination. Adjunctive use of WATS-3D yielded an additional 12 new cases of dysplasia (9 with crypt dysplasia and 3 with low-grade dysplasia [LGD]), for added yield of 34.3% (=12/35, 95% confidence interval 14.6%-62.2%). When restricting the analysis to LGD and higher, 21 dysplastic cases (15% of the total cases) were identified by HDWLE-NBI-VLE-SP, while WATS-3D found 4 additional new cases (3 with LGD and 1 with high-grade dysplasia) for an added yield of 19% (=4/21, 95% confidence interval 0.6%-45.7%). DISCUSSION: The addition of WATS-3D to an already thorough examination with HDWLE-NBI-VLE-SP may increase the yield of dysplasia detection.

Digital cholangioscopy can detect residual biliary stones missed by occlusion cholangiogram in ERCP: a prospective tandem study.

Background and study aims After stone removal in endoscopic retrograde cholangiopancreatography (ERCP), an occlusion cholangiogram (OC) is performed to confirm bile duct clearance. OC can miss residual stones that can lead to recurrent biliary symptoms. The aim of this study was to assess if digital peroral cholangioscopy (POC) increased the diagnostic yield of residual biliary stones that are missed with OC. Patients and methods Patients having ERCP performed for choledocholithiasis were enrolled into the study only if they had one of the following criteria: dilated bile duct ≥ 12 mm and/or if lithotripsy was being performed. An OC was performed to confirm duct clearance after removal of stones followed by POC, based on inclusion criteria. The incremental yield of biliary stones missed by OC but confirmed by POC was then measured. A total of 96 POC procedures were performed on 93 patients in two tertiary care centers. Results Residual biliary stones were found in 34 % of cases. The average bile duct size in cases with residual stones was 15.1 mm ±â€Š0.7 mm. One- to three-mm stones were found in 41 % of cases, 4- to 7-mm stones in 45 % of cases, and ≥ 8-mm stones in 14 % of cases. Lithotripsy was performed in 13 % of cases and was significantly associated with residual stones (30 % vs. 3 %, P  < 0.001). Conclusions Occlusion cholangiogram can miss residual stones in patients with dilated bile ducts and those receiving lithotripsy. Digital POC can increase the yield of residual stone detection in these patients and should be considered to confirm clearance of stones. (ClinicalTrials.gov-NCT03482375).

Effect of time of day and daily endoscopic workload on outcomes of endoscopic mucosal resection for large sessile colon polyps.

Background: Endoscopic mucosal resection of large non-pedunculated colon polyps is challenging. Objective: To determine if the time of day or daily endoscopic workload play a role in outcomes of endoscopic mucosal resection for large non-pedunculated colon polyps greater than 20 mm. Methods: This is a retrospective study of patients who underwent endoscopic mucosal resection of large non-pedunculated colon polyps. The time of day and endoscopic workload were compared across the following outcomes: the rate of complete resection of the polyp, the rate of referral for surgery, and the rate of residual neoplasia on follow-up. Results: One hundred and three endoscopic mucosal resection procedures were performed. There were no differences in the rates of complete resection (80.8% vs. 70.0%; P = 0.25), the need for surgery (27.4% vs. 33.3%; P = 0.55), and rate of residual neoplasia (24.5% vs. 50.0%; P = 0.07) when comparing the time of day. Colon polyps greater than 40 mm were less likely to be completely resected versus polyps sized 20-39 mm (56.8% vs. 91.9%; P < 0.001). In cases with no residual neoplasia on follow-up, the mean duration for the index procedure was 45.6 minutes versus 60.7 minutes when there was residual neoplasia (P < 0.01). Conclusion: The time of day and endoscopic workload does not affect outcomes for endoscopic mucosal resection of large non-pedunculated colon polyps, but the size of large non-pedunculated colon polyps and resection times do.

A High-Resolution Wireless Power Transfer and Data Communication System for Studying Gastric Slow Waves.

We present a wireless recording system designed for high-resolution mapping of gastric slow-wave signals. The system is composed of an implantable unit (IU), a wearable unit (WU), and a stationary unit (SU) connected to a computer. Two independent wireless data communication links consisting of IU-WU and IU-SU were developed based on near-field and far-field communication, respectively. Furthermore, the WU is capable to wirelessly recharge the IU's battery through an inductive link. For the IU-WU near-field communication, a differential pulse position data encoding algorithm with only 6.25% duty cycle, with load shift keying (LSK) modulation is developed to guarantee continuous power transmission and high data transfer rate, simultaneously. The IU sends the encoded data to the WU, and the WU can either store the data locally on a memory card or transmit them to the SU for real-time monitoring. In addition, the IU-SU far-field data communication was developed based on a RF transceiver in which the IU transmits the data directly to the SU. The benchtop validation of the system demonstrated successful IU-WU and WU-SU data transmission, while sample signals were recorded successfully at IU through saline solution and received by SU.

Initial experience with a novel resection and plication (RAP) method for acid reflux: a pilot study.

BACKGROUND AND STUDY AIMS: Current endoscopic therapies for gastroesophageal reflux disorder (GERD) are limited by technical complexity, and/or cost. We sought to evaluate the success of a novel resection and plication (RAP) anti-reflux procedure. PATIENTS AND METHODS: RAP was performed on 10 patients with GERD refractory to proton pump inhibitor (PPI) therapy. RAP consists of semi-circumferential mucosectomy along with full-thickness plication of the lower esophageal sphincter (LES) and cardia. We assessed the technical success and safety as well as followed GERD-Health Related Quality of Life (GERD-HRQL) scores and medication usage. RESULTS: All patients underwent RAP without adverse events and were discharged on the same day. Only half of the patients required general anesthesia. Follow-up ranged from 5 to 24 months (median 9 months) and all patients had a significant improvement in their GERD-HRQL scores ( P  < 0.0001, 95 % CI 19.3 - 25.3). 8 of 10 eliminated their daily PPI dependence. CONCLUSIONS: The RAP method has potential as an effective anti-reflux option. Its main advantages include a short procedure time, simple approach using readily available equipment, and possible avoidance of general anesthesia.

Incremental yield of dysplasia detection in Barrett's esophagus using volumetric laser endomicroscopy with and without laser marking compared with a standardized random biopsy protocol.

BACKGROUND AND AIMS: Volumetric laser endomicroscopy (VLE) is a new wide-field advanced imaging technology for Barrett's esophagus (BE). No data exist on incremental yield of dysplasia detection. Our aim is to report the incremental yield of dysplasia detection in BE using VLE. METHODS: This is a retrospective study from a prospectively maintained database from 2011 to 2017 comparing the dysplasia yield of 4 different surveillance strategies in an academic BE tertiary care referral center. The groups were (1) random biopsies (RB), (2) Seattle protocol random biopsies (SP), (3) VLE without laser marking (VLE), and (4) VLE with laser marking (VLEL). RESULTS: A total of 448 consecutive patients (79 RB, 95 SP, 168 VLE, and 106 VLEL) met the inclusion criteria. After adjusting for visible lesions, the total dysplasia yield was 5.7%, 19.6%, 24.8%, and 33.7%, respectively. When compared with just the SP group, the VLEL group had statistically higher rates of overall dysplasia yield (19.6% vs 33.7%, P = .03; odds ratio, 2.1, P = .03). Both the VLEL and VLE groups had statistically significant differences in neoplasia (high-grade dysplasia and intramucosal cancer) detection compared with the SP group (14% vs 1%, P = .001 and 11% vs 1%, P = .003). CONCLUSION: A surveillance strategy involving VLEL led to a statistically significant higher yield of dysplasia and neoplasia detection compared with a standard random biopsy protocol. These results support the use of VLEL for surveillance in BE in academic centers.

Lumen Apposing Metal Stents (LAMSs) for Drainage of Pancreatic and Gallbladder Collections: A Meta-analysis.

BACKGROUND AND AIMS: Endoscopic ultrasound-guided transmural drainage using lumen apposing metal stents (LAMSs) is becoming a popular and promising therapeutic approach for drainage of intra-abdominal fluid collections. There has been an increasing number of studies evaluating LAMS for drainage of pancreatic pseudocysts (PP), walled-off pancreatic necrosis (WOPN), and gallbladder (GB) drainage. The aim of this meta-analysis is to analyze the literature to date regarding the clinical success, technical success, and adverse events of LAMS in treatment of pancreatic fluid collections and GB drainage. METHODS: A comprehensive search of multiple literature databases through November 2016 was performed. Human studies with at least 10 subjects that examined the clinical success, technical success, and adverse events of LAMS in treating PP, WOPN, and GB drainage were included. RESULTS: A total of 993 patients (608-WOPN; 204-PP; 181-GB drainage) underwent drainage from 20 trials. For drainage of WOPN, the pooled technical success was 98.9% [95% confidence interval (CI): 98.2% to 99.7%] and clinical success was 90% (95% CI: 87% to 93%) (τ=0.001). For drainage of PP, the pooled technical success was 97% (95% CI: 95% to 99%) and clinical success was 98% (95% CI: 96% to 100%), (τ=0.001). For GB drainage, the pooled technical success was 95% (95% CI: 91% to 99%) and clinical success was 93% (95% CI: 90% to 97%), (τ=0.001). Total adverse events occurred in 11% of patients with higher complication rates observed in GB drainage. There was no evidence of publication bias in this meta-analysis. CONCLUSIONS: Endoscopic ultrasound-guided transmural drainage using LAMS is becoming a widely accepted therapeutic approach for the treatment of PP, WOPN, and GB drainage with high clinical and technical success rates and acceptable adverse events. Further prospective randomized trials reporting long-term clinical efficacy and cost-effectiveness are needed to validate LAMS as a therapeutic modality for pancreatic and GB collections.

An inductive narrow-pulse RFID telemetry system for gastric slow waves monitoring.

We present a passive data telemetry system for real-time monitoring of gastric electrical activity of a living subject. The system is composed of three subsystems: an implantable unit (IU), a wearable unit (WU), and a stationary unit (SU). Data communication between the IU and WU is based on a radio-frequency identification (RFID) link operating at 13.56 MHz. Since wireless power transmission and reverse data telemetry system share the same inductive interface, a load shift keying (LSK)-based differential pulse position (DPP) coding data communication with only 6.25% duty cycle is developed to guarantee consistent wireless downlink power transmission and uplink high data transfer rate, simultaneously. The clock and data are encoded into one signal by an MSP430 microcontroller (MCU) at the IU side. This signal is sent to the WU through the inductive link, where decoded by an MSP432 MCU. Finally, the retrieved data at the WU are transmitted to the SU connected to a PC via a 2.4 GHz transceiver for real-time display and analysis. The results of the measurements on the implemented test bench, demonstrate IU-WU 125 kb/s and WU-SU 2 Mb/s data transmission rate with no observed mismatch, while the data stream was randomly generated, and matching between the transmitted data by the IU and received by the SU verified by a custom-made automated software.

Systematic review and meta-analysis of single-balloon enteroscopy-assisted ERCP in patients with surgically altered GI anatomy.

BACKGROUND: Surgically altered pancreaticobiliary anatomy increases the difficulty of performing ERCP. Single-balloon enteroscopy (SBE) is a relatively new technique that can be used for ERCP in patients with surgically altered anatomy. OBJECTIVE: To evaluate the therapeutic and diagnostic success of SBE-ERCP among patients with surgically altered anatomy. DESIGN/SETTING: Systematic review and meta-analysis of studies involving SBE-ERCP in patients with Roux-en-Y gastric bypass, hepaticojejunostomy, or Whipple procedure. Enteroscopy success was defined as success in reaching the papilla and/or biliary anastomosis by using SBE. Diagnostic success was defined as obtaining a cholangiogram. Procedural success was defined as the ability to provide successful intervention, if appropriate. A random-effects model was used. RESULTS: A total of 461 patients underwent SBE-ERCP from 15 trials. The pooled enteroscopy, diagnostic, and procedural success rates were 80.9% (95% confidence interval [CI], 75.3%-86.4%), 69.4% (95% CI, 61.0%-77.9%), and 61.7% (95% CI, 52.9%-70.5%), respectively. There was statistical large heterogeneity for enteroscopy, diagnostic, and therapeutic success (P < .001 for all). Adverse events occurred in 6.5% (95% CI, 4.7%-9.1%) of patients. There was no evidence of publication bias in this meta-analysis. LIMITATIONS: Our findings and interpretations are limited by the quantity and heterogeneity of the studies included in the analysis. CONCLUSION: SBE-ERCP has high diagnostic and procedural success rates in this challenging patient population. It should be considered a first-line intervention when biliary access is required after Roux-en-Y gastric bypass, hepaticojejunostomy, or Whipple procedure.

Defective mucosal movement at the gastroesophageal junction in patients with gastroesophageal reflux disease.

BACKGROUND: Little is known about the role of muscularis mucosa at the gastroesophageal junction (GEJ). AIM: To evaluate the movement of the mucosa/muscularis-mucosa/submucosa (MMS) at the GEJ in normal subjects and in patients with gastroesophageal reflux disease (GERD). METHODS: Gastroesophageal junctions of 20 non-GERD subjects and 10 patients with GERD were evaluated during 5 mL swallows using two methods: in high-resolution endoluminal ultrasound and manometry, the change in the GEJ luminal pressures and cross-sectional area of esophageal wall layers were measured; in abdominal ultrasound, the MMS movement at the GEJ was analyzed. RESULTS: Endoluminal ultrasound: In the non-GERD subjects, the gastric MMS moved rostrally into the distal esophagus at 2.17 s after the bolus first reached the GEJ. In GERD patients, the gastric MMS did not move rostrally into the distal esophagus. The maximum change in cross-sectional area of gastroesophageal MMS in non-GERD subjects and in GERD patients was 289 % and 183%, respectively. Abdominal ultrasound: In non-GERD subjects, the gastric MMS starts to move rostrally significantly earlier and to a greater distance than muscularis propria (MP) after the initiation of the swallow (1.75 vs. 3.00 s) and (13.97 vs. 8.91 mm). In GERD patients, there is no significant difference in the movement of gastric MMS compared to MP (6.74 vs. 6.09 mm). The independent movement of the gastric MMS in GERD subjects was significantly less than in non-GERD subjects. CONCLUSION: In non-GERD subjects, the gastric MMS moves rostrally into the distal esophagus during deglutitive inhibition and forms a barrier. This movement of the MMS is defective in patients with GERD.

Ileocecal valve dysfunction in small intestinal bacterial overgrowth: a pilot study.

AIM: To explore whether patients with a defective ileocecal valve (ICV)/cecal distension reflex have small intestinal bacterial overgrowth. METHODS: Using a colonoscope, under conscious sedation, the ICV was intubated and the colonoscope was placed within the terminal ileum (TI). A manometry catheter with 4 pressure channels, spaced 1 cm apart, was passed through the biopsy channel of the colonoscope into the TI. The colonoscope was slowly withdrawn from the TI while the manometry catheter was advanced. The catheter was placed across the ICV so that at least one pressure port was within the TI, ICV and the cecum respectively. Pressures were continuously measured during air insufflation into the cecum, under direct endoscopic visualization, in 19 volunteers. Air was insufflated to a maximum of 40 mmHg to prevent barotrauma. All subjects underwent lactulose breath testing one month after the colonoscopy. The results of the breath tests were compared with the results of the pressures within the ICV during air insufflation. RESULTS: Nineteen subjects underwent colonoscopy with measurements of the ICV pressures after intubation of the ICV with a colonoscope. Initial baseline readings showed no statistical difference in the pressures of the TI and ICV, between subjects with positive lactulose breath tests and normal lactulose breath tests. The average peak ICV pressure during air insufflation into the cecum in subjects with normal lactulose breath tests was significantly higher than cecal pressures during air insufflation (49.33 ± 7.99 mmHg vs 16.40 ± 2.14 mmHg, P = 0.0011). The average percentage difference of the area under the pressure curve of the ICV from the cecum during air insufflations in subjects with normal lactulose breath tests was significantly higher (280.72% ± 43.29% vs 100% ± 0%, P = 0.0006). The average peak ICV pressure during air insufflation into the cecum in subjects with positive lactulose breath tests was not significantly different than cecal pressures during air insufflation 21.23 ± 3.52 mmHg vs 16.10 ± 3.39 mmHg. The average percentage difference of the area under the pressure curve of the ICV from the cecum during air insufflation was not significantly different 101.08% ± 7.96% vs 100% ± 0%. The total symptom score for subjects with normal lactulose breath tests and subjects with positive lactulose breath tests was not statistically different (13.30 ± 4.09 vs 24.14 ± 6.58). The ICV peak pressures during air insufflations were significantly higher in subjects with normal lactulose breath tests than in subjects with positive lactulose breath tests (P = 0.005). The average percent difference of the area under the pressure curve in the ICV from cecum was significantly higher in subjects with normal lactulose breath tests than in subjects with positive lactulose breath tests (P = 0.0012). Individuals with positive lactulose breath tests demonstrated symptom scores which were significantly higher for the following symptoms: not able to finish normal sized meal, feeling excessively full after meals, loss of appetite and bloating. CONCLUSION: Compared to normal, subjects with a positive lactulose breath test have a defective ICV cecal distension reflex. These subjects also more commonly have higher symptom scores.

Circular smooth muscle contributes to esophageal shortening during peristalsis.

AIM: To study the angle between the circular smooth muscle (CSM) and longitudinal smooth muscle (LSM) fibers in the distal esophagus. METHODS: In order to identify possible mechanisms for greater shortening in the distal compared to proximal esophagus during peristalsis, the angles between the LSM and CSM layers were measured in 9 cadavers. The outer longitudinal layer of the muscularis propria was exposed after stripping the outer serosa. The inner circular layer of the muscularis propria was then revealed after dissection of the esophageal mucosa and the underlying muscularis mucosa. Photographs of each specimen were taken with half of the open esophagus folded back showing both the outer longitudinal and inner circular muscle layers. Angles were measured every one cm for 10 cm proximal to the squamocolumnar junction (SCJ) by two independent investigators. Two human esophagi were obtained from organ transplant donors and the angles between the circular and longitudinal smooth muscle layers were measured using micro-computed tomography (micro CT) and Image J software. RESULTS: All data are presented as mean ± SE. The CSM to LSM angle at the SCJ and 1 cm proximal to SCJ on the autopsy specimens was 69.3 ± 4.62 degrees vs 74.9 ± 3.09 degrees, P = 0.32. The CSM to LSM angle at SCJ were statistically significantly lower than at 2, 3, 4 and 5 cm proximal to the SCJ, 69.3 ± 4.62 degrees vs 82.58 ± 1.34 degrees, 84.04 ± 1.64 degrees, 84.87 ± 1.04 degrees and 83.72 ± 1.42 degrees, P = 0.013, P = 0.008, P = 0.004, P = 0.009 respectively. The CSM to LSM angle at SCJ was also statistically significantly lower than the angles at 6, 7 and 8 cm proximal to the SCJ, 69.3 ± 4.62 degrees vs 80.18 ± 2.09 degrees, 81.81 ± 1.75 degrees and 80.96 ± 2.04 degrees, P = 0.05, P = 0.02, P = 0.03 respectively. The CSM to LSM angle at 1 cm proximal to SCJ was statistically significantly lower than at 3, 4 and 5 cm proximal to the SCJ, 74.94 ± 3.09 degrees vs 84.04 ± 1.64 degrees, 84.87 ± 1.04 degrees and 83.72 ± 1.42 degrees, P = 0.019, P = 0.008, P = 0.02 respectively. At 10 cm above SCJ the angle was 80.06 ± 2.13 degrees which is close to being perpendicular but less than 90 degrees. The CSM to LSM angles measured on virtual dissection of the esophagus and the stomach on micro CT at the SCJ and 1 cm proximal to the SCJ were 48.39 ± 0.72 degrees and 50.81 ± 1.59 degrees. Rather than the angle of the CSM and LSM being perpendicular in the esophagus we found an acute angulation between these two muscle groups throughout the lower 10 cm of the esophagus. CONCLUSION: The oblique angulation of the CSM may contribute to the significantly greater shortening of distal esophagus when compared to the mid and proximal esophagus during peristalsis.

The esophagogastric junction.

The following discussion of the esophagogastric junctions includes commentaries on the three component structures of the sphincteric segment between the stomach and the esophagus; the pressure contributions from the three sphincteric components in normal subjects and in gastroesophageal reflux (GERD) patients; the mechanism of action of endoscopic plication to determine the underlying pathophysiology of GERD; and in vitro muscle strip studies of defects within the gastroesophageal sphincteric segment potentially leading to GERD.

Pharmacologic specificity of nicotinic receptor-mediated relaxation of muscarinic receptor precontracted human gastric clasp and sling muscle fibers within the gastroesophageal junction.

Relaxation of gastric clasp and sling muscle fibers is involved the transient lower esophageal sphincter relaxations underlying the pathophysiology of gastroesophageal reflux disease (GERD). These fibers do not contribute tone to the high-pressure zone in GERD patients, indicating their role in pathophysiology. This study identifies some mediators of the nicotine-induced relaxation of muscarinic receptor precontracted gastric clasp and sling fibers. Muscle strips from organ donors precontracted with bethanechol were relaxed with nicotine and then rechallenged after washing and adding inhibitors tetrodotoxin (TTX), the nitric-oxide synthase inhibitor L-nitro-arginine methyl ester (L-NAME), the ß-adrenoceptor antagonist propranolol, the glycine receptor antagonist strychnine or ginkgolide B, and the GABA(A) receptor antagonist bicuculline or 2-(3-carboxypropyl)-3-amino-6-(4 methoxyphenyl)pyridazinium bromide [(gabazine) SR95531]. TTX only inhibited clasp fiber relaxations. L-NAME and propranolol inhibited, and ginkgolide B was ineffective in both. SR95531 was ineffective in clasp fibers and partially effective in sling fibers. Strychnine and bicuculline prevented relaxations with low potency, indicating actions not on glycine or GABA(A) receptors but more consistent with nicotinic receptor blockade. Bethanechol-precontracted fibers were relaxed by the nitric oxide donor S-nitroso-N-acetyl-DL-penicillamine and by the ß-adrenergic agonist isoproterenol (clasp fibers only) but not by the glycine receptor agonist taurine or glycine or the GABA(A) agonist muscimol. These data indicate that nicotinic receptor activation mediates relaxation via release of nitric oxide in clasp and sling fibers, norepinephrine acting on ß-adrenoceptors in clasp fibers, and GABA acting on GABA(A) receptors in sling fibers. Agents that selectively prevent these relaxations may be useful in the treatment of GERD.

Comparison of human and porcine gastric clasp and sling fiber contraction by M2 and M3 muscarinic receptors.

To compare the gastroesophageal junction of the human with the pig, M(2) and M(3) receptor densities and the potencies of M(2) and M(3) muscarinic receptor subtype selective antagonists were determined in gastric clasp and sling smooth muscle fibers. Total muscarinic and M(2) receptors are higher in pig than human clasp and sling fibers. M(3) receptors are higher in human compared with pig sling fibers but lower in human compared with pig clasp fibers. Clasp fibers have fewer M(3) receptors than sling fibers in both humans and pigs. Similar to human clasp fibers, pig clasp fibers contract significantly less than pig sling fibers. Analysis of the methoctramine Schild plot suggests that M(2) receptors are involved in mediating contraction in pig clasp and sling fibers. Darifenacin potency suggests that M(3) receptors mediate contraction in pig sling fibers and that M(2) and M(3) receptors mediate contraction in pig clasp fibers. Taken together, the data suggest that both M(2) and M(3) muscarinic receptors mediate the contraction in both pig clasp and sling fibers similar to human clasp and sling fibers.