ABSTRACT
BACKGROUND:In order to solve the problems of poly-l-lactic acid (PLLA) stents, such as poor support, acidic metabolites, we researched a novel biogradable stent-PLLA/amorphous calcium plosphate (ACP). OBJECTIVE: To discuss the safety and histocompatibility of the novel biogradable stent-PLLA/ACP stent implanted in the coronary artery in a porcine model. METHODS:Sixteen novel biogradable stents were randomly implanted into the coronary arteries, left anterior descending branch, left circumflex artery or right coronary artery of sixteen healthy Tibet miniature pigs. The blood routine and blood biochemistry were measured pre-operation and at 1 month after operation. The coronary blood vessels where the stent was implanted were examined by hematoxylin-eosin staining at 1 and 6 months after operation. RESULTS AND CONCLUSION: Compared with pre-operation, the post-operation indicators of the blood routine and blood biochemistry were of no significant difference. Coronary angiography revealed coronary artery patency and no thrombosis, the vascular stent segments exhibited clear boundaries with the surrounding tissue, with no tissue adhesion, necrosis, and adherence abnormalities. The results of hematoxylin-eosin staining showed that there was no significant difference in vascular injury integral between 1 month after operation and 6 months after operation. However, 6 months after operation, the scores of the inflammation were lower (P < 0.05), and the scores of the endothelialization were increased (P < 0.05). There was no myocardial infarction and inflammatory cellinfiltration around the stent. These results suggest that the novel biodegradable stent has good safety and histocompatibility.
ABSTRACT
BACKGROUND:At present, the main research fields about coronary stents are the whole degradation biological materials with high biocompatibility and drug control ed release systems. OBJECTIVE: To evaluate the safety after the two novel biodegradable stents implanted in coronary arteries in porcine models. METHODS:The normal ful y biodegradable stents were made up of the poly-L-lactide and the antiproliferative drugs paclitaxel, and the novel biodegradable stents were added in amorphic calcium phosphate at the basis of normal biodegradable stents. (1) Five normal ful y biodegradable stents were randomly implanted into the coronary arteries of five porcines, and five novel biodegradable stents were randomly implanted into the coronary arteries of the remaining five porcines by coronary angiography. The blood biochemistry and C-reactive protein levels were measured pre-operation and at 28 days after operation. Coronary angiography was utilized to observe the lumen unobstructed at 28 days after surgery. (2) Under a microscope, seven normal ful y biodegradable stents and seven novel biodegradable stents were implanted into right external iliac arteries of 14 rabbits. Blood urea nitrogen and creatinine levels were measured before surgery and at 28 days after operation. RESULTS AND CONCLUSION:At 28 days after operation, there were no significant changes in porcine glutamic-pyruvic transaminase, aspartate aminotransferase, triacylglycerol, total cholesterol, low density lipoprotein and C-reactive protein levels compared with that before operation, but urea nitrogen and creatinine levels were significantly higher than that before operation (P<0.05). The result of coronary angiography showed that no in-stent thrombosis or stenosis was detected in either group. There was no significant difference in urea nitrogen and creatinine levels in both groups. These results suggested that it is safe and compatible after the two novel biodegradable stents implanted in coronary arteries of porcine models, and the stents had good histocompatibility.
ABSTRACT
ObjectiveTo investigate the cause of clinically missed diagnosis of thyroid microcarcinoma(TMC) and the management. Methods Clinical diagnostic and therapeutic data of 110 cases with TMC operated and confirmed by pathology from Jan. 1985 to Dec. 2000 were analysed. Results Diagnostic positive rates by ultrasonography and freezing section were respectively 58%(15/26) and 66 7%(14/21) in 26 cases diagnosed preoperatively. Diagnostic positive rate of freezing section was 80%(24/30) in 30 cases discovered intraoperatively. Through postoperative pathologic exam,54 cases were confirmed as TMC that was not discovered in 19 cases by intraoperative freezing section.Total or near total thyroidectomy was only performed on 35 cases,lobectomy of one or both lobes on other cases. Follow up rate was 80 1% with time ranging from 6 months to 15 years. One case recurred without mortality.Conclusion The clinical diagnosis of TMC is often difficult to establish. Careful palpation, ultrasonography with fine needle aspiratiou cytology before operation, and thorough exploration of the suspected nodules in operation will help to heighten the diagnostic rate. Total or near total lobectomy fulfils the eradication of TMC.