BACKGROUND:Biliary stent is widely used in different biliary tract surgeries, and there are some defects in the use of biliary stent. OBJECTIVE:To explore the biodegradability and compatibility of polylactide/glycolide biliary stent. METHODS:The polylactide/glycolide biliary stent was prepared, and immersed in the bile. At 1, 2, 3, 4 and 5 weeks after soaking, eight experimental stents were dried and placed under the scanning electron microscope. In the sterile condition, the stent was implanted under the rat skin. At 1, 2, 3, 4, and 5 weeks after implantation, two rats were sacrificed. The stent was taken out. The appearance of the stent and muscle structure of experimental animals was observed. The gross appearance of stent was observed at different time by scanning electron microscopy. The rate of degradation was calculated. The muscle structure of experimental animal and the stent were understood. RESULTS AND CONCLUSION:At 1 week, stent shape remained almost intact, but the texture became soft;surface roughness and cracks gradual y appeared;stent wal col apse was visible. The stent was completely degraded at 5 weeks. Before degradation, the stent presented clear three-dimensional reticular structure observed by scanning electron microscopy. With the time extended, the stent surface and section corrosion became worsened. By gel permeation chromatography detection, at 1 week of implantation, the molecular mass of the stent declined rapidly, and then gradual y declined. At 2 weeks, the relative molecular mass decreased to 15 000. At 4 weeks, stent mass loss was approximately 40%. Al the experimental animals were survived, no poisoning, al ergy or heat source response. The operative wound was healed wel , and no infection occurred. By histological observation, at 5 weeks, the stent was completely degraded, with a degradation rate of 100%. Surrounding muscles recovered to a normal state. These results indicate that the polylactide/glycolide biliary stent has good degradation in vitro and biocompatibility.

Objective To investigate Paragonimus westermani infection in the intermediate hosts and animal reservoivs in Jiangxi Province. \ Methods\ Two forest farms in Jingan and Wanzai Counties and one town in Yushan County of Jiangxi Province were selected as pilots for epidemiological and retrospective survey. The intermediate hosts (snails, crabs) and reservoir hosts(cat, dog, civet cat, wildcat, etc.) were collected and examined. Data on the changes of ecological environment and people's behaviors were also collected. \ Results \ The average infection rate in Semisulcospira libertina and Sinopotamon spp. was 0\^21% and 54\^3% respectively, and that of reservoir hosts was 5\^6%. Compared with those in 20 years ago, the infection rate in Sinopotamon spp. decreased considerably. \{Conclusion\}\ The three areas are still endemic for P.westermani with lower prevalence than before possibly due to the change of ecological environment.