After the factors that influence the selection of words were analyzed according to the problems in selec-tion of words for co-word analysis, a hypothesis for how to select the word sets with its verification analysis was pro-posed, the method for selecting words was thus decided according to the word frequency-covered literature area and the number of high frequency words. However, its practical use in large data sets needs to be further improved.

Portal hypertension (PH) referes to an abnormal increase in portal venous pressure due to increased resistance and/or blood flow of the portal vein or backflow obstruction of the hepatic veins and often manifests as splenomegaly, hypersplenism, gastroesophageal varices and bleeding, ascites, and hepatic encephalopathy. Liver synthetic dysfunction is often seen in sinusoidal PH caused by liver cirrhosis, while it is less often seen in pre-hepatic/pre-sinusoidal PH due to abnormalities in the extrahepatic and intrahepatic portal veins or post-hepatic/post-sinusoidal PH due to backflow obstruction of the extrahepatic and intrahepatic hepatic veins. The presence or absence of PH can be determined by clinical symptoms, signs, and hematological parameters, and type and etiology can be clarified by imaging examinations, hepatic venous pressure gradient, and histopathological features. In addition to the active treatment of primary diseases, nonselective beta-blockers, endoscopy, and interventional or surgical therapy should be used for the prevention and treatment of PH complications.

Liver cirrhosis is the leading cause of liver-related death globally, and the most common causes of liver cirrhosis are chronic hepatitis B and C, alcoholic liver disease, and nonalcoholic fatty liver disease. Recent studies have shown that despite an increase in the number of deaths due to liver cirrhosis around the world, there is a reduction in age-standardized death. In China, there are increases in number of patients with liver cirrhosis, prevalence rate of liver cirrhosis, number of deaths due to liver cirrhosis, and mortality rate of liver cirrhosis, while there are reductions in age-standardized prevalence rate and mortality rate; chronic hepatitis B remains the main cause of liver cirrhosis, with a gradual increase in the proportion of liver cirrhosis cases caused by alcoholic and nonalcoholic fatty liver diseases.

Objective:To observe whether α1 adrenergic receptor (α1AR) blocker can reduce and antagonize portal hypertension caused by α1AR activation in rats, and to provide a new approach for the clinical treatment of portal hypertension.Methods:Phenylephrine was chosen as α1AR agonist, and alfuzosin was used as α1AR blocker. The route of administration was portal vein injection, and the pressure was measured by trans-portal vein puncture. According to random number table, 32 male Sprague-Dawley rats were divided into 4 groups: control group, portal hypertension model group, alfuzosin treatment group and alfuzosin prevention group. The portal venous pressure (PVP) was measured in all rats before administration. The rats in the control group were injected with 0.9% sodium chloride solution (1 L/g), and the rats in portal hypertension model group were injected with phenylephrine(1.5 μg/g), and the PVP of the above two groups was measured again at 5 and 10 min after injection. The rats in alfuzosin treatment group were injected with phenylephrine(1.5 μg/g), PVP was measured again at 5 min after administration, and then the rats were given alfuzosin(0.9 μg/g), PVP was measured again at 5 min after administration. The rats in alfuzosin prevention group were injected with alfuzosin(0.9 μg/g), PVP was measured at 1 min after administration, and then the rats were given phenylephrine(1.5 μg/g), PVP was measured again at 1, 5 and 10 min after phenylephrine injection respectively. One way analysis of variance and Dunnett- t test were used for statistical analysis. Results:The portal vein puncture was successfully performed in 4, 6, 8 and 5 rats in the control group, portal hypertension model group, alfuzosin treatment group and alfuzosin prevention group, respectively. The PVP of rats in portal hypertension model group at 5 and 10 min after phenylephrine injection was (18.045±7.636) and (15.515±5.440) mmHg (1 mmHg = 0.133 kPa), respectively, which were both higher than that before administration ((8.452±2.830) mmHg), and the differences were statistically significant ( t=2.89 and 2.82, both P<0.05). At 5 min after alfuzosin injection, the PVP of rats in the alfuzosin treatment group was (10.088±3.743) mmHg, which was lower than that of rats at 5 min after phenylephrine injection ((16.146±4.324) mmHg) and that of portal hypertension model group at 10 min after phenylephrine injection, and the differences were statistically significant ( t=3.00 and 2.22, both P<0.05). There were no significant differences in PVP in the alfuzosin prevention group before administration, at 1 min after injection of alfuzosin, and at 1, 5 and 10 min after injection of phenylephrine (all P > 0.05). Conclusions:α1AR is an important factor involved in the regulation of PVP, and its blockers can reduce and antagonize the portal hypertension caused by α1AR activation, which is of great significance in the prevention and treatment of portal hypertension progression in liver cirrhosis.

Objective:To investigate the antimicrobial properties of copper-loaded coatings on the surface of ureteral stents and their biocompatibility in order to determine the most suitable level of copper loading.Methods:Copper-loaded PDA coatings with different copper contents were constructed on the surface of polyurethane (PU) stents using polydopamine (PDA) and dimethylaminomethylborane (DMAB). The antibacterial property of the coating against Escherichia coli and Staphylococcus aureus was investigated by the plate counting method. The bacterial adhesion on the coating surface was studied by scanning electron microscopy. Using the live/dead evaluation, microbes were stained and observed by a fluorescence microscope. The biocompatibility of the copper-loaded coatings was detected by a cell proliferation assay incubated with L929 cells.Results:The antibacterial rates of the copper-loaded samples exceeded 90% after incubation with E. coli and S. aureus for 24 h, respectively, and the antibacterial performance increased with the increase of copper content in the coating. The amount of bacteria adhered to the surface of the copper-loaded samples was significantly lower, and most of them were dead bacteria. When the copper content in the coating preparation solution used was 0.25~1 g/L, the cell proliferation rate on the surface of the copper-loaded coating was higher than 80% and the material was not cytotoxic.Conclusions:A copper-loaded PDA coating with excellent antibacterial properties and good biocompatibility can be prepared with a copper content of 1 g/L in the coating preparation solution, forming a potential solution for the preparation of ureteral stent coatings.

Transjugular intrahepatic portosystemic shunt （TIPS） has been recommended as a treatment method for cirrhotic portal hypertension in domestic and foreign guidelines， but there is still uncertainty in its therapeutic efficacy. More and more studies have shown that TIPS combined with collateral vessel embolization （TIPS+E） has certain advantages in the treatment of gastroesophageal variceal bleeding in liver cirrhosis. This article reviews the major studies on TIPS+E in China and globally， summarizes related recommendations in guidelines and the current status of clinical application， and proposes the issues that need to be solved， such as indication， hemodynamic criteria， and selection of materials for embolization， and large－sample multicenter randomized controlled trials are needed for further clarification.

Objective:To describe the current status of registration and design characteristics of clinical trials of new drugs for curing hepatitis B through domestic and foreign websites, so as to provide references for the follow-up clinical trials of new hepatitis B drugs.Methods:A search was conducted on the US Clinical Trials Database and the Chinese Clinical Trial Registry Center. The search date was from the establishment of the database to May 26, 2020, and the registration trials of new drugs for curing hepatitis B at home and abroad were included. Two researchers independently searched and screened the literature and extracted the data.Results:A total of 106 registered clinical trials of new drugs for curing hepatitis B were included (94 English registration websites and 12 Chinese registration websites), and the number of registrations had increased year by year. Among them, the proportion of therapeutic vaccines and core protein inhibitors were the highest, accounting for 27.4% ( n = 29) and 22.6% ( n = 24), respectively. The vast majority of clinical trials ( n = 96, 90.6%) were in the early stages (Phase I and II). The subjects in phase I clinical trial were mainly healthy people and treated CHB patients, while the subjects in phase II clinical trial were mainly CHB patients who had achieved viral suppression after initial or post-treatment. The main evaluation indicators of Phase I clinical trials were the safety and tolerability of new drugs. The main evaluation indicators in about half of Phase II clinical trials were HBsAg negative conversion/quantitative decline. Overall, the number of clinical trials with the new design was small, accounting for 3.8% (4 / 106). There were relatively few trials of new drugs for curing hepatitis B on domestic registration websites, and the information provided was incomplete. Conclusion:The number of clinical trials of new hepatitis B drugs at home and abroad is increasing year by year, but most of them are in phase I and II, with few adopting new designs. In addition, the information integrity of the domestic website registration center needs to be improved.