[Exosomes derived from miR-133a-3p engineered mesenchymal stem cells promote myocardial repair in rats after acute myocardial infarction].

Objective: To investigate the effects of exosome derived from miR-133a-3p engineered human umbilical cord blood mesenchymal stem cells (ucMSC) on myocardial repair after acute myocardial infarction (AMI) in rats. Methods: UcMSC was amplified and cultured in vitro. Lentiviral carrying miR-133a-3p and negative control vectors were transfected into ucMSC. Exosomes secreted by the transfected ucMSC were named miR-133a-3p-Exo and miR-NC-Exo, respectively. The AMI model of rats was established by ligation of the left anterior descending coronary artery. MiR-133a-3p-Exo or miR-NC-Exo were then injected into the border zone of the infarct area. Cardiac function was assessed by echocardiography after twenty-eight days of intervention, and Masson staining was used to evaluate the area of myocardial fibrosis post-AMI. The myocardial apoptosis after infarction was evaluated by TUNEL staining and the angiogenesis after infarction was evaluated by immunofluorescence staining in the current study. Results: Compared with the miR-NC-Exo group, the left ventricular ejection fraction in the miR-133a-3p-Exo group was significantly increased ((47.4%±9.8%) vs. (64.2%±8.9%), P<0.05). While the myocardial fibrosis area ((31.2%±7.3%) vs. (18.0%±1.5%), P<0.01) and the percentage of apoptotic cardiomyocytes ((25.6%±3.6%) vs. (15.1%±4.4%), P<0.05) was significantly reduced in the miR-133a-Exo group. Besides, the expression of CD31 and α-smooth muscle actin (α-SMA) were also increased significantly in the miR-133a-3p-Exo group compared to the miR-NC-Exo group (CD31: (2.9±0.9) vs. (13.9±2.0), P<0.000 1, α-SMA: (3.5±0.9) vs. (11.0±1.6), P<0.000 1). Conclusion: Exosome derived from miR-133a-3p engineered ucMSC effectively inhibited myocardial apoptosis and promoted angiogenesis, thus improving the cardiac function after myocardial infarction in rats.

Development of a novel piezoelectric-driven non-resonant elliptical vibrator with adjustable characteristics.

Aiming at the fabrication of a micro-textured surface, a novel piezoelectric-driven non-resonant elliptical vibrator is proposed in this paper; the output characteristics could be adjusted by the length change of the tool holder. The flexible mechanism is the primary structure of the vibrator, which includes a lever type mechanism, an enhanced Scott-Russell mechanism, and a T-shaped mechanism. The former two mechanisms are used to enlarge the output of the piezoelectric actuator, and the T-shaped mechanism is applied to transfer the parallel movements to the elliptical trajectory. The theoretical models including the elliptical trajectory, output stiffness, and resonant frequencies are established to investigate the impacts of the tool holder and controlling signals on the output characteristics of the vibrator, which are further validated using the finite element analysis method. A prototype is developed by integrating the non-resonant elliptical vibrator assembly and controlling system. Some experiments are carried out to verify the basic performance and the adjustable properties of the vibrator.

[Clinical characteristics and prognosis of intraductal papillary mucinous neoplasm of the biliary tract].

Objective: To study the clinical features, diagnosis, surgery treatment and prognosis of intraductal papillary mucinous neoplasm of the biliary tract (IPMN-B). Methods: The data of 16 patients with IPMN-B admitted to The First Hospital of Jilin University and Xi'an Third Hospital from January 2014 to January 2018 were retrospectively analyzed. Kaplan-Meier method was used to conduct the survival analysis. These patients included 10 males and 6 females, the median age was 57 years. Results: Clinical manifestations were mainly jaundice (11 cases), upper abdominal pain (12 cases) and hyperpyretic chills (4 cases), combined with bile duct stones (14 cases) and hepatic lobe atrophy (2 cases). The average size of the tumor was (2.6±0.7) cm. All of 16 cases were diagnosed as IPMN-B, including 5 cases of invasive carcinoma (4 cases were perineural invasion) without vascular invasion and 6 cases of non-invasion carcinoma. The pathological type included 8 cases of pancreaticobiliary duct type, 5 cases of gastric type, 2 cases of intestinal type and 1 case of eosinophils type. Laboratory tests showed abnormal liver function (12 cases), increased direct bilirubin (9 cases), increased carbohydrate antigen199 (CA199, 8 cases) and carcinoembryonic antigen (CEA, 4 cases). The enhanced CT detection showed 9 cases of intrabile duct mass and 14 cases of bile duct dilatation. Surgical resection is the main treatment method, including 2 cases of partial resection of liver, 12 cases of bile duct mass resection combined with choledochojejunostomy and 2 cases of pancreatoduodenectomy, all of whom achieved R0 resection. Fifteen patients were followed up and 4 died during the period. The median postoperative progression free survival was 31 months (95% CI: 33-47 months), and the recurrence rate at 1 year, 2-years and 3-years were 6.7%, 40.0% and 73.3%, respectively. The median overall survival was 35 months (95% CI: 23-47 months), and the 1 year, 2-years, and 3-years cumulative survival rates were 100%, 80.0%, and 53.3%, respectively. Conclusions: IPMN-B is a rare tumor of biliary tract system, which is difficult to be diagnosed early. The main treatment is surgical resection, which can achieve a good prognosis.

[Analysis of writing age of ballpoint pen ink by thin-layer chromatography].

A method based on using a thin-layer chromatographic method (TLC) for determining changes in dye of ballpoint pen ink developed with writing age. An ink drawn line of 1 cm in length was cut and placed in Eppendorf tube. Extraction was performed with 20 microL ethanol at room temperature for 15 min, and heated in steambath for 10 min. The ethanol solution(4 microL) containing the extracted dyes was then spotted on TLC plate by syringe after cooling. The ballpoint pen ink spots were eluted in a solvent of isopropyl alcohol. Using TLC scanner, the spots on TLC plate were scanned at 580 nm. The relations between ratio of peak heights and writing age were attained. Thus, the information on relative writing age can be obtained. And, the powerful evidence for identifying the age of ballpoint pen ink is provided by this method in the field of forensic science.