Objective To investigate lymph node metastasis on the middle and lower segment of lⅡ and Ⅲ stage of esophageal squamous cell carcinomas,understand the factors influencing the lymph node metastasis,and provide the basis for the key areas of lymph node cleaning.Methods A retrospective study was made on the specimens of 186 patients who were middle and lower segment of Ⅱ and Ⅲ stage of esophageal squamous cell carcinomas,who had underwent radical operation through left thoracic,thoraco abdominal two field lymph node cleaning.All the cases were patients from April 2010 to December 2013 at the Inner Mongolia Medical University Clinical Medical College of Chifeng.Results A percentage (67.9％) of patients (126/186) was found with lymph node metastasis.A total of 4259 lymph node was dissected,with an averaged cleaning of (22.9 ± 8.1) lymph nodes for each case.A total of 622 lymph nodes (14.6％ =622/4 259) existed metastasis.The rate of mediastinum metastasis for middle and lower segment of esophageal cancer was 56.1％ and 16.5％,respectively.The rate of metastasis to the lower mediastinal lymph nodes was 34.6％ and 54.4％,respectively.The rate of metastasis to the celiac lymph nodes was 23.4％ and 46.8％,respectively.A significant difference was found in the metastasis locations of middle and lower segment of esophageal carcinomas (P ＜ 0.05).The top three locations of lymph node metastasis in the middle segment of esophageal squamous cell carcinomas were the lymph nodes of left artery paraesophageal,carina,and gastric bypass.The top three locations of lymph node metastasis in the lower segment of esophageal squamous cell carcinomas were paraesophageal,cardia,and gastric lymph nodes.The depths of tumor invasion,differentiation,intravascular cancer embolus were statistically significant effect on lymph node metastasis rate (P ＜ 0.05).Tumor location,and lesion length had no significant effect on the lymph node metastasis rate (P ＞ 0.05).Conclusions The lower segment of Ⅱ,Ⅲ stage esophageal squamous cell carcinoma with lymph node metastasis occurs in the lower mediastinal and abdominal lymph nodes.The middle segment Ⅱ,Ⅲ stage esophageal squamous cell carcinoma with lymph node metastasis occurs in the thoracic and abdominal lymph nodes with Jump transfer characteristics.The lymph node cleaning of the mid-dle segment includes the left artery near the stomach,paraesophageal,and carina lymph node.The lymph node cleaning of the lower segment includes paraesophageal,cardia,and gastric lymph nodes.The metastasis rate of vascular tumor thrombus is related to the depth of tumor invasion and differentiation degree.

Objective To explore the advantages and disadvantages of helicopter emergency medical services of South China in the long-distance transport for critical patients.Methods A total of 30 patients who received helicopter emergency medical services by Guangdong Generral Hospital from August 2004 to December 2014 were selected as the observation group,and the other 30 patients with similar conditions who received ground emergency medical services were selected as the control group.To analyses the difference between the two groups in the disease,transport distance,transportation time,costs and compliction by χ2-test,t-test and nonparametric test according types of data.Results There were significantly difference between two groups in transport distances (km) [578.0 (313.0,707.5)vs.214.5 (101.5,313.5),P <0.05],set-up time (min) [95.7 (56.7,133.4)vs.10.7 (6.8,15.7),P <0.05],transportation time (min) [112.3 (64.3,152.4) vs.146.8 (67.8,217.5),P <0.05],costs (yuan/h) [14378.5 (9887.0,16348.5)vs.557.0 (356.5, 787.5),P <0.05]and the distance/total time value [2.8 (1.3,4.8)vs.1.4 (0.8,2.8),P <0.05]. There was no significantly difference in the incidence of complications between two groups (χ2 =0.058,P >0.05).Conclusions Helicopter emergency medical services could shorten the transportation time of critical patients on long distance transportation,and improve the efficiency of first-aid.However,there were many disadvantages that need to be improved in the helicopter emergency medical service of China.

OBJECTIVE：To identify and evaluate the risk factors of innovative drug clinical trials ，and to provide references for the development of risk management and control strategies. METHODS ：Using the method of literature research ，the risk factors of innovative drug clinical trials were obtained ，classified and sorted out ，and the risk evaluation indicators were initially formed. On this basis ，the questionnaire was designed. By means of interview and questionnaire survey ，54 experts were invited from 4 tertiary hospitals and 1 contract research organization to score. SPSS 24.0 software was used to perform principal component analysis on risk event status data. RESULTS & CONCLUSIONS ：The risk evaluation system included 9 first-class indicators such as policy and legal risk ，clinical trial institution risk and trial scheme design risk ，and 31 second-class indicators such as industrial policy，law and regulation changes ，intellectual property risk . According to the analysis ，the risk factors of innovative drug clinical trials mainly included drug and biological sample management risk ，trial scheme design risk ，clinical trial institution risk ，safety report management risk ，ethical review risk ，policy and legal risk ，and subject management risk. Relevant parties in clinical trials need to focus on monitoring various risk factors ，establish dynamic monitoring and control mechanism and implementation guarantee mechanism ，and effectively prevent and control risk ，to promote the smooth implementation of clinical trials.

Biodegradable vascular stents have better biocompatibility than drug-eluting stents. The blood vessels are rebuilt and degraded after normal physiological functions are restored. Due to it will not stay in the body for a long time and the patients don't need taking anti-rejection drugs all the time, it becomes the focus of attention in the treatment of coronary heart disease. This article introduced the development history of biodegradable stents and reviewed the research status of several different materials of vascular stents (animals or humans)
Absorbable Implants ; Animals ; Drug-Eluting Stents ; Humans ; Stents