The content of optical isomerism is the difficult point of organic chemistry teaching, and so case-based learning (CBL), theoretical-experimental integration teaching method and micro class teaching methods are tried to be used in classroom teaching according to the actual teaching situations. For CBL teaching method, the course is guided by the step of introduction-question-discussion and summary-exten-sions; For theoretical-experimental integration teaching method, combined with the theory class, the two experiments including the determination of optical rotation and organic molecular model are set for the opti-cal isomer content, to enhance the students' understanding of theoretical knowledge through the hands-on operation;For micro class teaching method, the key and difficult points of this chapter are dug out and about 10 minutes of video are recorded by using common video software before class, which are introduced in the classroom or provided to students after class for repeated watching, to deepen the students' understanding of the concept and phenomenon of optical isomers. In brief, it is important to combine various teaching method to improve the classroom instructing effectively and stimulate the students' interest in organic chemistry.

Objective To evaluate the efficacy of interventional catheter drainage combined with ozone therapy for the management of postoperative enterocutaneous fistula. Method A total of 70 patients with postoperative enterocutaneous fistula were enrolled and divided into group A (35, conventional surgical treatment) and group B (35, interventional catheter drainage and ozone therapy). Clinical efficiency, hospital stays, hospital expenses and complications were compared. Follow-up observations of the infection score in 2 groups before and after treatment (3 days, 1 week, 2 weeks and 1 month) were also compared. Results 30 cases in group A recovered (85.7%), and 28 cases in group B recovered (80.0%), the result of which shows no statistic significance. The hospital stays and expense in group B were significantly lower than those in group A. 4 cases of group A suffered from incision complications , 2 intra-abdominal hemorrhage , 1 severe pneumonia and 1 septic shock. 2 cases in group B suffered from stomachache. The differences can be shown significantly. The infection score between the two groups shows no significant difference, but the score was found to be obviously lower after treatment than before. The infection score decreased by an average of 19.9 in group A and 23.5 in group B,indicating a better anti-infective effect in group B. Conclusion Interventional catheter drainage combined with ozone therapy for the management of postoperative enterocutaneous fistula is safe and effective, with lower hospital stays and expense.

Objective To investigate the characteristics of nerve injury and incidence of carpal tunnel syndrome(CTS)indiabeticpatientsbymeasuringthenerveconductionvelocity(NCV). Methods Atotalof387 inpatients with type 2 diabetes were selected in Kaifeng Central Hospital from July 1, 2011 to October 1, 2014. The abnormal rates of NCV between left and right or male and female for the same name nerve were compared. The examinations to median nerves were paid particular attention and the segmental test was performed. Results Among 387 patients, 333 cases showed abnormal NCV, and 162 patients (41. 9%) presented with CTS. The incidence of sensory nerve injury was higher than that of motor nerve injury. The nerve injury often occurred in the dominant hand, but the injury of bilateral hand were also found in some patients. In 162 patients with CTS, 91 patients presented with clinical manifestations and signs, and the rest were without discomfort in their hands. The percentages of SCV(34. 1%vs 25. 6%, P=0. 012) and MCV (40. 3% vs 29. 5%, P=0. 020) abnormality in the right median nerve were higher than those in the left side. No significant difference of the other nerves was found between left and right. Significant differences in the percentages of abnormality in SCV of the left median nerve (21. 4%vs 30. 5%, P=0. 047) and the right median nerve (28. 6%vs 40. 1%, P=0. 013) between man and woman were found. The abnormal rates of other nerves were without statistically significant between man and women. Conclusions The incidence of CTS is high in diabetic patients. Usually, it firstly occurs in sensory nerves, followed by motor nerves, especially in the dominant hand.

Objective To investigate the incidence,location and morphological features of Laimer fibers between mucosal layer and inner circular muscularispropria in patients with achalasia.Methods Data of 107 patients with achalasia who underwent POEM between May 2010 and June 2013 were collected.Endoscopic video was reviewed to determine the incidence of Laimer fibers and the corresponding images were analyzed according to gender,age,Ling typing and location of Laimer fibers.Results Laimer fibers were found in lower esophageal sphincter of 44 patients (41.12％).There were no significant differences in the incidences of Laimer fiber among groups with different age or gender (P ＞ 0.05).The incidence in Ling type Ⅱb was 46.15％ (12/26),and 45.83％ (22/48) in Ling type Ⅰ,0 in Ling type Ⅲ.There was no significant difference among the groups of Ling type (x2 =2.042,P =0.564).All Laimer fibers were found in lower esophageal sphincter and the majority of which were in right wall (36.45 ％,39/107),followed by left wall (3.74％,4/107) and none was found in anterior wall (x2 =107.468,P =0.000).Conclusion Laimer fibers generally exists in lower esophageal sphincter and most of which are discovered on right wall of the esophagus.Further study is needed to explore its role in development and treatment of achalasia.

Objective To determine the incidence and clinical factors associated with bleeding after endoscopic submucosal dissection (ESD) of gastric mucosal lesions.Methods Clinical,endoscopic and pathological data of 223 lesions in 215 ESD patients between January 2009 and October 2011 were collected.The following factors associated with bleeding were analyzed:( 1 ) patient-related factors:sex,age,concomitant diseases including hypertension and diabetes mellitus,history of administration of anticoagulants or antiplatelet agents; (2) lesion-related factors:size,location,ulcer or scar findings,macroscopic types and pathological types; (3) procedure-related factors:en-bloc resection,spray of porcine fibrin sealant and operation time. Results Thirteen patients (13 lesions ) developed bleeding after ESD,among whom 7(53.8％) occurred within 24 hours after the procedure,5 (38.5％) within 1 week and 1 (7.7％) on the sixteenth day after ESD.Univariate and multivariate analysis revealed that lesion size ( ≥5 cm; odds ratio 8.663 ; 95％ CI:2.081 - 36.075) was an independent risk factor for bleeding.Conclusion Lesion size is the independent risk factor for bleeding after ESD,so careful preparation and close monitoring are required during and after ESD.In the meantime efforts should be made to identify and exactly demarcate lesions to minimize the size of resected specimens and reduce the risk of bleeding after ESD.

ObjectiveTo evaluate preoperative biopsy in the treatment of gastric mucosal lesions by endoscopic submucosal dissection (ESD).MethodsClinical data of 195 patients diagnosed as having gastric intraepithelial neoplasia (GIEN) or early cancer by preoperative biopsy were retrospectively analyzed.The discrepancy between endoscopic biopsies and pathological diagnosis after ESD were studied.ResultsThe overall consistency rate between preoperative biopsies and postoperative pathological diagnosis was 93.8％ (183/195) and complete consistency rate was 50.8％ (99/195).For low-grade and highgrade gastric intraepithelial neoplasia ( LGIEN),the complete consistency rates were 49.4％ (42/85)and 38.0％ (30/79),respectively,which were not different ( P ＞ 0.05 ).For early cancer it was 87.1％(27/31 ),which was significantly higher than those in the LGIEN group and HGIEN group ( P ＜ 0.05 ).Post-ESD diagnosis was more severe than biopsy in 66 patients (33.8％,66/195 ),including 36 LGIEN (42.4％,36/85) and 30 HGIEN (38.0％,30/79).Final pathological diagnosis was milder than biopsy in 18 patients (9.2％,18/195),i.e.14 HGIEN (17.7％,14/79) and 4 early cancer (12.9％,4/31).Gastritis was diagnosed in 12 patients (6.2％,12/195),i.e.7 LGIEN (8.2％,7/85) and 5 HGIEN (6.3％,5/79).ConclusionPreoperative biopsy is insufficient for accurate diagnosis of gastric mucosal lesions,but facilitates resection of gastric mucosal lesions by ESD.

Objective To evaluate the curative effect of asymptotic full-thickness myotomy type of peroral endoscopic myotomy(POEM) for achalasia.Methods Data of 41 patients who underwent asymptotic POEM at our digestive endoscopy center from December 10th 2010 to January 10th 2014 were retrospectively studied.The postoperative and preoperative symptoms and reflux were compared.Results The postoperative Eckardt scores of symptoms of 41 patients improved significantly(P ＜ 0.001) compared with before.Esophageal dynamic pressure also showed the effectiveness of symptom relief.The incidence of postoperative reflux in symptoms and gastroscopy were 26.83％ and 27.27％,respectively.Conclusion Asymptotic fullthickness myotomy POEM can alleviate the symptoms of achalasia and the effect of inhibiting reflux is generally satisfactory.

Objective To compare the curative effect of thoracic endovascular repair (TEVAR) plus medication with that of pure medication in treating uncomplicated type B aortic dissection,and to discuss the treatment strategy for uncomplicated type B aortic dissection.Methods The clinical data of 118 patients with definitely confirmed uncomplicated type B aortic dissection,who were admitted to authors' hospital during the period from 2004 to 2015,were retrospectively analyzed.Among the 118 patients,57 patients received TEVAR plus medication (TEVAR group) and 61 patients were treated with pure medication (drug group).The complications and mortality within one month and during follow-up period in both groups were calculated respectively,and Kaplan-Meier survival curves were used to compare the survival rate between the two groups.Results The incidences of complications and morbidity during hospitalization and within one month after treatment in TEVAR group were 5.2％ and 0％ respectively,which in the drug group were 0％ and 0％ respectively.The patients were followed up for 1-110 months,with a mean of (43.3±36.7) months.The incidence of main complications and the mortality in TEVAR group were 7.0％ and 5.3％ respectively,which in the drug group were 6.6％ and 8.1％ respectively.The one-,2-,4-and 7-year cumulative survival rates in TEVAR group were 100％,97.1％,93.5％ and 78.0％ respectively,which in the drug group were 98.4％,96.4％,90.8％ and 72.7％ respectively,the differences between the two groups were not statistically significant (~=0.019,P=0.890).Conclusion For the treatment of uncomplicated type B aortic dissection,TEVAR plus medication is superior to pure drug therapy in reducing expansion rate of false cavity,but TEVAR carries some procedure-related complications,besides,TEVAR can not improve the survival rate.(J Intervent Radiol,2017,26:266-269)

Objective To analyze the learning curve of an experienced interventional radiologist engaged in thoracic endovascular aortic repair (TEVAR) for Stanford type B aortic dissection.Methods The clinical data of 70 patients with Stanford type B aortic dissection,who received TEVAR that was carried out by the same group of interventional physicians over the past 10 years,were retrospectively analyzed.According to the sequence of operation date,the patients were equally divided into group A,B,C,D and E with 14 patients in each group.The operation time,procedure-related complications,postoperative hospitalization days were compared among the 5 groups,and the curative effects at different stages were evaluated.Results No statistically significant differences in the age,sex,classification,concurrent hypertension,concurrent diabetes,active smoking,maximum diameter of false lumen,viscera artery supplied by the false lumen,etc.existed between each other among the 5 groups (P＞0.05).The operation time of group A and group B was (3.29±0.61) hours and (2.87±0.37) respectively (P＜0.05),while the operation time of group C,group D and group E was (1.80±0.62) hours (1.74±0.34) hours and (1.52±0.39) hours respectively (P＞0.05).The operation time of group A and group B was significantly longer than that of group C,D,and E (P＜0.001).The difference in the occurrence of complications was not statistically significant between each other among the 5 groups (P＞0.05).The hospitalization time was gradually shortened from group A to group E,although the difference was not statistically significant (P＞0.05).The surgeries of 28 patients in group A and group B were completed within 2 years and 6.2 years respectively,with an operation frequency being 3.3 patients per year and 7 patients per year respectively;while the surgeries of 42 patients in group C,group D and group E were completed within 2.2 years,1.2 years and 0.5 years respectively,with an operation frequency being 6.4 patients per year,11.7 patients per year and 17.5 patients per year respectively.Conclusion The learning curve of performing TEVAR for type B aortic dissection is approximately 28 cases;after completing 28 TEVAR procedures for type B aortic dissection at the yearly frequency of 4.6 cases by one interventional radiologist,the operation time becomes significantly shortened,and the surgical skills of theinterventional physician team can been significantly improved.

Objective To evaluate the technique of transpancreatic septum precut for cannulation of inaccessible common bile duct in endoscopic retrograde cholangiopancreatography (ERCP). Methods Data of 109 patients with difficult biliary cannulation in ERCP, of whom 56 underwent transpancreatic septum precut and 53 had needle-knife sphincterotomy from January 2006 to July 2008, were analyzed retrospectively, and the success rate of cannulation and the occurrence of complications were compared between the two methods. Results Of 109 patients accepted precut papillotomy, common bile duct cannulation was successfully achieved in 97. The success rates of transpancreatic septum precut group and needle-knife sphincterotomy group were 96.4% (54/56) and 81.1% (43/53) respectively, which was significantly different (P<0.05). Complications occurred in 11 cases, including bleeding(n =4), acute pancreatitis(n=5), cholangitis(n=2). The tolal frequency of complications of the transpancreatic septum pre-cut papillotomy group was lower than that of needle-knife sphincterotomy group(3.6% vs. 17.0%, P<0.05). Conclusion In patients with inaccessible bile ducts, transpancreatic septum precut is a safe and effective procedure in cannulation, exhibiting a higher success rate and lower occurrence of complication when compared with needle-knife sphincterotomy.