Objective:To explore the risk factors and preventive strategies of pancreatitis after percutaneous transhepatic biliary drainage (PTBD) in patients with pancreatic cancer and obstructive jaundice.Methods:A total of 241 patients were retrospectively analyzed from May 2001 to October 2014 in Tianjin Medical University Cancer Institute and Hospital. The possibly correlated 9 factors were analyzed, including gender, age, hemoglobin level, total bilirubin level, degree of pancreatic duct dilatation, degree of pancreatic atrophy, degree of biliary stenosis, the pancreatic duct visualization, and drainage mode.Results:Univariate analysis suggested that pancreatic duct dilatation, pancreatic atrophy, visualized pancreatic duct and drainage mode were associated with the incidence of pancreatitis after PTBD ( P<0.05). Logistic regression analysis showed that visualization of pancreatic duct ( OR=6.33) was a risk factor for pancreatitis, while pancreatic duct dilatation ( OR=0.14), pancreatic atrophy ( OR=0.12) and external drainage ( OR=0.11) were protective factors for pancreatitis. Conclusion:In pateints with pancreatic cancer and obstructive jaundice, pancreatic duct dilatation and pancreatic atrophy predict low risk of pancreatitis after PTBD,while intraoperative pancreatic duct visualization and internal or external drainage may increase the incidence of postoperative pancreatitis.

It is still at the initial stage for basic-level military doctors to participate in the standardized residency training. While, their professional backgrounds and training objectives are significantly different from those civilian residents, it is necessary to explore the standardized training methods in line with the military career demands for those basic-level military doctors. Based on the actual needs of grass-roots troops and military medicine, this study makes significant progress in the integration of standardized residency training and field surgery training methods, making the basic-level military doctors achieve the goal of field surgery training in the course of clinical practice of residents. Not only the surgical capability of basic-level military doctors, but also the medical support capability in grass-roots troops has been improved. This article summarizes the application methods and experience of field surgery teaching in the standardized residency training of military medical residents at the grass-roots level.

Objective:To conduct theoretical analysis and experimental research on peripherally inserted venous catheters, establish theoretical models of interaction between different materials catheters and simulated skin tissues, and test different catheters at the same time to provide theoretical basis and experimental basis for the optimization design.Methods:According to the mechanical properties of the catheter at 25 ℃ and 37 ℃, a finite element model of the catheter and simulate skin tissue was established. The relationship between catheter folds and material and structure during puncture was analyzed, and the stiffness, radiographic properties, etc. were tested experimentally.Results:The performance of the catheter at different temperatures is closely related to its material. The wrinkle situation of the catheter is related to the catheter material and the inclination of the wedge surface. The elastic modulus of the polyurethane (PU) catheter is about 500 MPa and 250 MPa, respectively at room temperature (25 ℃) and body temperature (37 ℃), which meets the clinical needs of high rigidity during puncture and soft material during indwelling. When the catheter structure is the same, the PU catheter is less prone to wrinkles than the fluorinated ethylene propylene copolymer (FEP) catheter. When the catheter material is the same, the smaller the inclination of the wedge surface, the less likely the catheter to wrinkle.Conclusions:Appropriately reducing the inclination of the wedge-shaped surface of the needle of peripherally inserted venous catheters can improve the success rate of puncture. The PU catheters have good mechanical properties, they are not prone to wrinkles during puncture, and their stiffness can be reduced at body temperature, which can not only increase the success rate of puncture, but also reduce the occurrence of complications. Therefore, PU catheters have a better clinical application prospect.

Objective:To describe a systematic approach on identification of poisonous mushroom by investigating two cases of Omphalotus guepiniformis poisoning in Jianyang district, Nanping, Fujian province. Methods:Two incidents of food poisoning on 10 migrant workers were investigated. The remaining suspected mushroom samples were collected and the same fresh mushroom specimens were also collected in the following field investigations from the same dead tree and fallen trunk. These mushroom specimens were identified based on morphological and phylogenetic analyses.Results:On November 24 and 26, 2018, 8 and 2 migrant workers from Jianyang District, Nanping ate wild mushrooms and developed acute nausea, vomiting, abdominal pain and other symptoms within 10 to 90 min after consumption. They were diagnosed as mushroom poisoning, with gastroenteritis as the main manifestation. Further analysis showed that the more poisonous mushroom were consumed, the shorter latency and longer duration of nausea and vomiting were resulted. After admission, gastric lavage, catharsis, acid preparation, gastric protection, fluid replenishment and other symptomatic support treatments were given in time, all patients were discharged in 1-3 d. Based on morphological and phylogenetic analyses, the samples were identified as O. guepiniformis. Conclusions:The two incidents were caused by accidental consumption of O. guepiniformis. Awareness education about poisonous mushroom should be provided to migrant workers to prevent more such poisoning incidents in the future.

Objective:To evaluate the clinicopathological features of primary retroperitoneal paragangliomas.Methods:Data of 24 patients with retroperitoneal paragangliomas who underwent surgical treatment in our hospital from Jan 2015 to Dec 2018 was collected and analyzed.Results:Hypertension, abdominal pain/discomfort and headache were the most common complaints while 10 patients were asymptomatic and were diagnosed accidently in routine body examination. Tumor size ranged from 3.4-13.0 cm (6.9±2.5) cm, and all the tumors were located in the vicinity of abdominal aorta and inferior vena cava. All the patients received surgical treatment. Intraoperative blood pressure fluctuations were significantly correlated with prolonged operation time, more blood loss, more blood transfusion and prolonged length of stay (all P<0.05). The median follow-up time was 29 months and 1 patient died from tumor recurrence and progression. The other patients have had a tumor free survival. Conclusions:Surgical resection was the principal treatment of primary paraganglioma. Preoperative assessment was very important for perioperative safety.

Objective:To investigate the pathogeny, diagnosis and treatment of solitary fibrous tumors of the abdomen and pelvis.Methods:Retrospective analysis was made on the clinical data of 12 SFT patients undergoing surgical resection in Peking University International Hospital from Jul 2015 to Jul 2019.Results:All patients underwent radical resection. After operation, complications in clued pelvic hemorrhage in 1 case and ureteral fistula in 1 case, all improved after conservative treatment.According to pathological and immunohistochemical results, 7 cases were MSFT and 5 cases were SFT. All patients were followed up for 2-53 months. 5 cases were recurrent, among which 1 case died of intestinal obstruction caused by tumor compression.Conclusion:The clinical manifestations of solitary fibrous tumors are mostly nonspecific.Imaging examination and puncture pathology are of great significance for preoperative diagnosis. Radical resection is an important means to improve the prognosis of patients.

Objective To analyze the influence from size parameters of minimally invasive vascular clamp on mechanical properties of small arteries. Methods The finite element simulation analysis on the process of minimally invasive vascular clamp clamping small arteries was performed. The influence patterns of 5 different sawtooth spacing, sawtooth heights and sawtooth lengths on mechanical properties of small arteries were studied. Results Larger sawtooth spacing led to smaller maximum equivalent stress of the clamped artery. The maximum equivalent stress of the small artery was not linear with the sawtooth height of the vascular clamp. The maximum equivalent stress of the small artery was the smallest and the vascular injury was the minimal when the swatooth height was 75 μm. The sawtooth length of the vascular clamp had an important influence on mechanical properties of clamped small arteries. The maximum equivalent stress of the artery was proportional to the sawtooth length of the vascular clamp. Conclusions The size parameters of minimally invasive vascular clamp had an important influence on mechanical properties in the process of clamping small arteries. The research findings can provide guidance for the design of the minimally invasive vascular clamp.

Objective The current manipulator with double parallel quadrilateral mechanism should be connected in series with a flexible degree of freedom (DOF) mechanism, which increases the volume of the manipulator, decreases the motion flexibility and creates the interference between the mechanical arms that hold the mirror and the device. Aimed at solving this problem, a novel mechanical arm was put forward to enhance the motion flexibility and reduce the volume of the manipulator. Methods The mechanical arm was designed by using the mechanism of five-link, slider and slide rail lower pair and wire transmission to realize the telescopic movement of the end effector. The kinematics model of the manipulator was established, and the MATLAB was used as the simulation tool to verify the correctness of the D-H parameters under the specific zero joint angle, and the motion equation of the manipulator was solved. Meanwhile, the three-dimensional workspace of the end effector was obtained by using Monte Carlo algorithm, and the preoperative plan of animal experiment for 3 arms was performed. Finally, cholecystectomy and other operations were acted in pigs, to verify the rationality and maneuverability of the design of double 5-link 2-DOF manipulator. Results The working space of Monte Carlo algorithm under MATLAB environment was -650.4 mm＜x＜649 mm, 163.8 mm＜y＜1 202 mm and -254.6 mm＜z＜829.8 mm. Sixteen cases of pig cholecystectomy were successfully completed, with an average operation time of 51 minutes. Conclusions The novel double 5-link 2-DOF manipulator could successfully complete cholecystectomy and other operations in pigs, which had no other symptoms after the operation. There was no interference between the mechanical arms, which fully verified the feasibility of the design scheme of the robot manipulator for minimally invasive surgery.

Objective To investigate the value of improving the prediction accuracy of near-term risk for developing breast cancer by transforming the original mammography image and fusing the different types of image features using the algorithm of machine learning.Methods The craniocaudal (CC) full-field digital mammography (FFDM) of 185 women were downloaded from the clinical database at the university of Pittsburgh medical center.Firstly,the original gray images were segmented and transformed into virtual optical density images.Then the asymmetry features were separately extracted from original gray images and virtual optical density images.Two decision tree classifiers of the first stage were trained based on the features extracted from two types of image.And the scores output from the two classifiers were used as input to train the second stage of one decision tree classifier.Leave-one-case-out method was used to validate the prediction performance of near-term risk of breast cancer.Results Using two-stage decision tree fusion method to predict breast cancer,the area under the ROC curve (AUC) was 0.9612±0.0132.And the sensitivity,specificity and prediction accuracy were 96.63％(86/89),91.67％(88/96) and 94.05％(174/185).Conclusion The features extracted from virtual optical density image have higher discriminatory power of predicting breast cancer.Fusing the two kinds of image features twice by two-stage decision tree method can help to improve the prediction accuracy of near-term risk of breast cancer.

Astract: Objective To explore the efifcacy and safety of endoscopic tissue adhesive injection in treatment of gastric variceal bleeding from liver cirrhosis.Methods Object of study are 92 cirrhotic patients (72 male/20 female) in hospital, who had been diagnosed with gastric varices bleeding from June 2014 to May 2016. Child-Pugh score at presentation for cirrhotic patients was A-28; B-36; C-28. According to endoscopic classiifcation of gastric varices, GEV1 were detected in 80 patients, GEV2 in 12. All patients were treated with endoscopic hypertonic glucose tissue adhesive ‘sandwich’ injection.Result Successful injection rate was 100.0% in 92 patients, among which 40 patients had accepted emergency endoscopic treatment and the immediate hemostasis rate was 100.0%. 65 patients were Having gastroscope review after the injection six months, 22 patients were significantly effective, accounting for 33.8%; 38 patients were effective, accounting for 58.4%; 5 patients were invalid, accounting for 7.7%. All the patients were followed up in 1 to 24 months. The late-rebleeding rate was 2.2%. None of them were having early-rebleeding or dead; Complications the incidence of rebleeding rate which caused by removing the needles which trapped in the varices was 2.2%. The incidence of chest pain rate was 4.3%, the bloating rate was 6.5% and the ulceration rate was 15.2%. There was no complications like fever, infection, stomachache, embolism and so on.Conclusion With low rebleeding rate and light side-effect, endoscopic tissue adhesive injection in the treatment of gastric variceal bleeding caused by cirrhosis portal hypertension has really good effect.