Somatostatin receptor 1 (SSTR1) is a crucial therapeutic target for various neuroendocrine and oncological disorders. Current SSTR1-targeted treatments, including the first-generation somatostatin analog lanreotide (Lan) and the second-generation analog pasireotide (Pas), show promise but encounter challenges related to selectivity and efficacy. This study presents high-resolution cryo-electron microscopy structures of SSTR1 complexed with Lan or Pas, revealing the distinct mechanisms of ligand-binding and activation. These structures illustrate unique conformational changes in the SSTR1 orthosteric pocket induced by each ligand, which are critical for receptor activation and ligand selectivity. Combined with the biochemical assays and molecular dynamics simulations, our results provide a comparative analysis of binding characteristics within the SSTR family, highlighting subtle differences in SSTR1 activation by Lan and Pas. These insights pave the way for designing next-generation therapies with enhanced efficacy and reduced side effects through improved receptor subtype selectivity.

Objective:To evaluate the diagnostic value of rapid on-site evaluation (ROSE) performed by endoscopists for solid pancreatic lesions requiring tissue for immunohistochemistry (IHC) staining with different approach of endoscopic ultrasound-guided tissue acquisition (EUS-TA).Methods:After screening 1 573 cases who underwent EUS-TA operation at the Endoscopy Center of Peking Union Medical College Hospital between August 2018 and October 2022, a total of 65 cases of solid pancreatic lesions whose diagnosis rely on IHC staining was collected and summarized with clinical data of each case. Among 65 cases, there were 46 cases of pancreatic neuroendocrine tumors (PNETs), 13 cases of pancreatic solid pseudo-papillary tumors (SPTs), and 6 cases of lymphomas and mesenchymal. Patients were categorized into ROSE group (36 cases) and non-ROSE group (29 cases) according to the presence or absence of endoscopists performed ROSE during EUS-TA operation. They were further divided into subgroups of FNA-ROSE (26 cases), FNB-ROSE (10 cases), FNA-non-ROSE (24 cases) and FNB-non-ROSE (5 cases) according to the type of EUS-TA. Diagnostic accuracy and IHC success rate were compared between different groups and subgroups. Binomial logistic multifactorial regression analysis was used to evaluate the influence of ROSE and EUS-TA type on diagnostic accuracy and IHC success rate.Results:There were no statistically significant differences between ROSE group and non-ROSE group in terms of age, gender, bilirubin level, CA19-9 level, lesion site, lesion size, composition ratio of diagnosis, and surgical rate. The differences in mean size of lesions, needle gauge, location of puncturation, and number of needle pass between subgroups were not statistically significant. The diagnostic accuracy was 88.9% in ROSE group and 79.3% in non-ROSE group, and the difference between the two groups was statistically significant ( P=0.023). The diagnostic accuracy of FNA-ROSE group was higher than that of FNA-non-ROSE group (88.5% vs 75.0%), but the difference was not statistically significant ( P>0.100). The differences in diagnostic accuracy and success rate of IHC between FNB-ROSE group and FNB-non-ROSE group were not statistically significant. Binomial logistic multifactorial regression analysis did not reveal any independent influences on diagnostic accuracy. Conclusions:ROSE performed by endoscopists improved diagnostic accuracy of EUS-TA in solid pancreatic lesions requiring IHC staining, and therefore is potentially valuable for improving the diagnostic efficiency of EUS-TA for such diseases.

Objective:To analyze clinical characteristics of primary pancreatic lymphoma (PPL) patients.Methods:Clinical features of 22 patients diagnosed as PPL admitted to Peking Union Medical College Hospital from January 2002 to May 2023 were analyzed retrospectively.Results:The median age was 56.4±13.3 years. The median time from onset to diagnosis was 1.0 (1.0, 3.0) months. The main clinical manifestations were abdominal pain (15/22), weight loss (14/22) and jaundice (10/22). Elevated lactate dehydrogenase (LDH) was observed in 15/20 (75%) patients. Only 2 (2/9, 22.2%) patients had increased CA199 levels and 2 (2/9, 22.2%) patients had increased CEA levels. The maximum tumor diameter was 5.0 (3.8, 6.9) cm. Contrast-enhanced CT mostly showed low enhancement lesions. Major pancreatic duct dilatation were rare on CT scan (4/20). Fifteen patients were confirmed by pancreatic pathology, of which 8 were obtained by surgery, 4 were obtained by CT or ultrasound-guided percutaneous biopsy, and 3 were obtained by EUS-FNA. The main pathological type was diffuse large B-cell lymphoma (14/22). 19 patients received chemotherapy, and 6 patients died with a median follow-up of 5.0 (1.5, 35.5) months.Conclusions:PPL is rare and easy to be misdiagnosed. Elevated LDH levels, normal tumor markers, and non-dilatation of main pancreatic duct are important diagnostic clues. It is important to obtain pathology by EUS-FNA and other methods for definite diagnosis.

To explore the application value of endoscopic ultrasound fine-needle aspiration (EUS-FNA) and endoscopic retrograde cholangiopancreatography (ERCP) in the diagnosis and treatment ofpatients with pancreatic cancer combined with obstructive jaundice.

Objective:To assess the efficacy of endoscopic transmural drainage, transpapillary drainage and their combination in reducing cyst recurrence in patients with disconnected pancreatic duct syndrome (DPDS).Methods:A retrospective study was conducted involving 22 patients diagnosed as having DPDS in Peking Union Medical College Hospital from January 2018 to December 2022. Patient data including clinical information, imaging characteristics, drainage technique, complications, and outcomes were extracted from the medical records and telephone follow-up.Results:There were 27 endoscopic treatments in 22 patients, which were categorized into 3 groups based on the procedural approach: transmural in 11 cases, transpapillary in 8, and the combination of both in 8. The combined drainage group exhibited a significantly higher drainage success rate (100.0%, 8/8) compared with the transpapillary group (50.0%, 4/8, P=0.012), with no significant difference compared with the transmural group [90.9% (10/11), P=0.621]. The one-year recurrence rate was significantly lower in the combined drainage group [0.0% (0/8)] than that in the transmural drainage group [55.6% (5/9), P=0.018], and transpapillary drainage alone [42.9% (3/7)] though it did not reach significance ( P=0.085). No significant differences were observed in treatment success rate [45.5% (5/11), 75.0% (6/8) and 87.5% (7/8), H=3.890, P=0.143], or complication incidence [54.5% (6/11), 75.0% (6/8) and 25.0% (2/8), H=3.909, P=0.142]. Conclusion:Transmural drainage combined with pancreatic duct stent placement results in satisfactory drainage of cystic fluid in the short term and significantly reduces one-year recurrence among patients with DPDS.

Objective:To evaluate the development and application of gastrointestinal endoscopy technology in Beijing-Tianjin-Hebei (BTH) region from 2016 to 2020, and the impact of the corona virus disease 2019 (COVID-19) epidemic on gastrointestinal endoscopy screening and lesion detection rate of medical institutions.Methods:Data of gastroscopy and colonoscopy cases from 26 cooperative institutions in BTH Region Gastrointestinal Endoscopy Medical Association from January 2016 to December 2020 were collected by questionnaire. The number of gastrointestinal endoscopy, the detection of main lesions (including upper gastrointestinal malignant tumors, early gastric cancer and colon cancer), and the number of endoscopic treatment were retrospectively analyzed by year.Results:From 2016 to 2019, the number of gastroscopy and colonoscopy showed a yearly increasing trend with an annual growth rate of over 10%. Compared with 2019, the number of gastroscopy and colonoscopy decreased by 10.86% and 8.29%, respectively, in 2020 due to the impact of the epidemic. The annual detection rates of upper gastrointestinal malignant tumors, early gastric cancer and colon cancer were on a rise, from 7.22%, 1.49% and 8.98% in 2016 to 9.87%, 2.71% and 12.04% in 2020, respectively. The number of gastroscopic mucosal resection, submucosal dissection and colonoscopic endoscopic submucosal dissection increased yearly, from 2 132, 300 and 217 cases in 2016 to 5 466, 872 and 560 cases in 2020, respectively.Conclusion:The Medical Association has promoted the expansion of endoscopic screening and the application of endoscopic treatment techniques, resulting in a continuous increase in the endoscopy detection rate and early cancer diagnosis rate in the BTH region. The sharp decrease of gastrointestinal endoscopy procedures and the increase in the lesion detection rate in 2020 reflect the impact of epidemic COVID-19 on detection of gastrointestinal cancers.

Objective:To investigate the role of endoscopic ultrasonography (EUS) in differentiating between autoimmune pancreatitis (AIP) and pancreatic cancer (PC).Methods:Data of 133 patients with AIP and 113 patients with PC who underwent EUS because of obstructive jaundice at Peking Union Medical College Hospital from January 2013 to December 2018 were retrospectively analyzed in the study, and were randomly divided into either a derivation sample or a validation sample using 1∶1 allocation according to the random number. In the derivation sample, 10 EUS characteristics were used to construct a prediction model to distinguish between AIP and PC, in which predictors were identified by multivariate stepwise logistic regression analysis and predictive efficacy was evaluated by receiver operating characteristics (ROC) curve analysis. The predictive efficacy was assessed in the validation sample. In view of the subjectivity in the judgment of diffuse/focal hypoechogenicity, 2 prediction models were designed in order to avoid bias.Results:By multivariate stepwise logistic regression analysis, diffuse hypoechogenicity ( OR=591.0, 95% CI: 98.8->999.9, P<0.001) and vessel involvement ( OR=11.9, 95% CI: 1.4-260.2, P=0.023) were identified as statistically significant predictors for distinguishing AIP from PC. EUS characteristics excluding diffuse/focal hypoechogenicity were stepped by logistic regression, which showed that hyperechoic foci/strands ( OR=177.3, 95% CI: 18.7->999.9, P<0.001), pancreatic duct dilation ( OR=60.5, 95% CI: 6.2->999.9, P=0.004), bile duct wall thickening ( OR=35.4, 95% CI: 3.7->999.9, P=0.009), lymphadenopathy ( OR=16.8, 95% CI: 1.7-475.2, P=0.038) and vessel involvement ( OR=22.7, 95% CI: 2.0-725.7, P=0.028) were statistically significant predictors to distinguish the two diseases. Both prediction models were built in the derivation sample, with area under the ROC curve of 0.995 and 0.979 respectively. In the validation sample, sensitivity, specificity, accuracy, positive predictive value and negative predictive value of both prediction models were all >90% by using the optimal cutoff value. Even for discrimination between focal AIP and PC, sensitivity and accuracy of both models were >90%, and specificity, positive predictive value and negative predictive value were all >85%. Conclusion:The 2 prediction models have good differential predictive value, and EUS is a useful tool to differentiate between AIP and PC.

Objective:To explore the effect of nursing based on knowledge, attitude and practice theory in the prevention of postoperative stoma infection in patients with bladder cancer.Methods:Using the convenient sampling method, a total of 78 patients with bladder cancer postoperative stoma who were hospitalized in Xuzhou Central Hospital from March 2016 to October 2020 were selected as the research objects. According to the random number table method, the patients were divided into the control group and the observation group, with 39 cases in each. The control group was given routine postoperative stoma nursing, while the observation group was given nursing based on knowledge, attitude and practice theory on the basis of the control group. After the intervention, the blood indexes (red blood cells, white blood cells, platelets and hemoglobin counts) related to stoma infection were compared between the two groups. Complications (hematuria, shock, urinary retention, wound rupture) were observed and recorded in the two groups; stoma infection during hospitalization and reinfection within 1, 3 and 6 months after surgery of the two groups were recorded.Results:After intervention, the red blood cell, hemoglobin and platelet counts in the observation group were higher than those in the control group, and the differences were statistically significant ( P<0.05) . The total incidence of postoperative complications of hematuria, shock, urinary retention and wound rupture in the observation group was 2.6% (1/39) , which was lower than 17.9% (7/39) in the control group, and the difference was statistically significant ( P<0.05) . There was 1 case (2.6%) of stoma infection in the observation group and6 cases (15.4%) in the control group, and the difference was statistically significant ( P<0.05) . Further follow-up showed that the proportions of reinfection in the observation group at 1, 3 and 6 months after surgery were lower than those in the control group, but there was no statistically significant difference between the two groups ( P>0.05) . Conclusions:Nursing based on the knowledge, attitude and practice theory can effectively improve the blood indexes related to infection after ostomy in bladder cancer patients and reduce the occurrences of complications and stoma reinfection.

Objective:To summarize the clinical characteristics of bleeding during endoscopic submucosal dissection (ESD) and to analyze the risk factors for bleeding.Methods:Data of patients who received gastric ESD in endoscopy center of Peking Union Medical College Hospital from January 2015 to December 2019 were reviewed. The medical history, characteristics of gastric lesions, operation process and prognosis of the patients were analyzed.Results:A total of 437 gastric lesions of 422 patients were included in this study, and 406 lesions were gastric epithelial tumors. The bleeding rate during ESD was 32.3% (141/437), including 2 cases of acute massive hemorrhage. Intraoperative hemorrhage during ESD increased the incidence of myometrial injury and intraoperative perforation, and prolonged the operation time. Multivariate regression analysis showed that risk factors for bleeding during ESD were anatomical adhesion, the lesion location in the upper and middle 2/3 of the stomach, the lesion area ≥ 15 cm 2, male, and non-ESD absolute indications. Conclusion:Bleeding is the speed limiting factor for gastric ESD. For male patients, when the lesion is located in the upper and middle 2/3 of the stomach, large with anatomical adhesion during operation, precaution should be taken for intraoperative hemorrhage.

Objective:To explore the endoscopic features of early gastric cancer (EGC) related to non-curative endoscopic resection, and to construct an assessment model to quantify the risk of non-curative resection.Methods:From August 2006 to October 2019, 378 lesions that underwent endoscopic resection and were diagnosed pathological as EGC in the Department of Gastroenterology, Peking Union Medical College Hospital were included in this case-control study.Seventy-eight (20.6%) non-curative resection lesions were included in the observation group, and 234 lesions which selected from 300 lesions of curative resection were included in the control group according to the difference of operation year ±1 with the observation group, and the ratio of 1∶3 of the observation group to the control group. Univariate and multivariate logistic regression analysis were performed to explore the risk factors for non-curative resection. The independent risk factor with the minimum β coefficient was assigned 1 point, and the remaining factors were scored according to the ratio of their β coefficient to the minimum. A predictive model was established to analyze the 378 lesions.The non-curative resection rates of lesions of different scores were calculated. Results:Univariate analysis showed that the lesion diameter, the location, redness, ulcer or ulcer scar, fold interruption, fold entanglement, and invasion depth observed with endoscopic ultrasonography (EUS) were associated with non-curative resection of EGC lesions ( P<0.05), and contact or spontaneous bleeding may be associated with non-curative resection ( P=0.068). Multivariate logistic regression analysis showed that submucosal involvement (VS confined to the mucosa: β=0.901, P=0.011, OR=2.46, 95% CI: 1.23-4.92), lesion diameter of 3-<5 cm (VS <3 cm: β=0.723, P=0.038, OR=2.06, 95% CI: 1.04-4.09), lesion diameter of ≥5 cm (VS <3 cm: β=2.078, P=0.003, OR=7.99, 95% CI: 2.02-31.66), location in the upper 1/3 of the stomach (VS lower 1/3: β=1.540, P<0.001, OR=4.66, 95% CI: 2.30-9.45), and fold interruption ( β=2.287, P=0.008, OR=1.93, 95% CI: 0.95-3.93) were independent risk factors for non-curative resection of EGC lesions. The factor of lesion diameter of 3-<5 cm and submucosal involvement were assigned 1 point respectively, location in the upper 1/3 of the stomach was assigned 2 points, diameter of ≥5 cm and fold interruption were assigned 3 points respectively, and other factors were assigned 0 point. Then the analysis of 378 lesions showed that the probability of non-curative resection at ≥2 points was 41.9% (37/93), 4 times as much as that at 0 [11.5% (25/217)]. Conclusion:EGC lesions with diameter ≥3 cm, located in the upper 1/3 of the stomach, interrupted folds or submucosal involvement are highly related to non-curative resection. The predictive model based on these factors achieves satisfactory efficacy, but it still needs further validation in larger cohorts.