Objective To determine the effect and safety of metallic stents in the treatment of acute malignant colorectal obstruction.Methods From May,2000 to June,2003, self-expanding metallic stents were implanted in 15 patients with acute left colonic obstruction caused by malignancies. The postoperative remission and complications were observed.Results Stents were implanted successfully in 12 cases(80.0%,12/15).Of the 12 cases,the obstruction were all disappeared within 24h. No death or colonic perforation happened in this series. Stent migration and anal pain developed each in one case after stent implantation. Elective radical resection was performed on 8 cases after bowel preparation and supportive therapy; and stents reserved permanently in other 4 cases. Conclusions The implantation of self-expanding metallic stents is a safe and effective method for the temporary remission or permanent treatment of acute left-colonic or rectal obstruction caused by malignancies,it can instead of colostomy.

BACKGROUND: Experiments have demonstrated that autologous vascular endothelial cells if transplanted onto artificial vascular cavosurface, can enhance the patency rate of vasotransplantation. Whether seeding of prostheses interposition grafts with bone marrow-derived endothelial cells is effective for in vivo endothelialization of artificial vessels remains unclear.OBJECTIVE: To observe the effect of endothelialization of vascular prosthesis by seeding prostheses interposition grafts with bone marrow-derived endothelial cells in animals.DESIGN: A controlled animal experimental study.SETTING: Shanghai Sixth People's Hospital.MATERIALS: This study was carried out in the Shanghai Sixth People's Hospital between September 2000 and October 2001. Twenty hybrid dogs from Shanghai, of either gender, aged 1.0 to 2.0 years old, weighing (18.7±2.3) kg, were involved in this study.METHODS: Bone marrow-derived mononuclear cells were isolated from the dogs. The endothelialization of ePTFE prostheses interposition grafts (4 mm×4 cm and 8 mm×5 cm)was carried out. Common carotid artery transplantation:Ten laboratory dogs were involved. Common carotid artery of 4 cm was resected from each dog. ePTFE prostheses interposition grafts of 4 mm×4 cm was transplanted into the bilateral common carotid artery, and prostheses interposition grafts were performed endothelialization, namely experimental group. Those prostheses interposition grafts, which were not performed endothelialization, were named as control group. Five dogs were used in each group. Patency rate and blood flow rate of transplanted vessels were detected with a color ultrasonograph 2 weeks and 2 months after operation.Inferior caval vein transplantation: Six of the rest 10 dogs were used for experiments. Under the anesthesia, 8-10 cm inferior caval vein was dissociated from each dog. Its two ends were blocked, and about 5 cm inferior caval vein was resected. ePTFE endothelialized vascular prosthesis with 8 mm in diameter and 5 cm in length was anastomosed end to end with 5-0 Prolene. The other 4 dogs were used for control experiment. ePTFE vascular prosthesis with the same specification was used as prostheses interposition graft. Vascular patency rate was determined 2 months after operation.At the same time, coverage rate and intimal thickness of transplanted vascular endothelial cells and vascular intimal thickness were determined.MAIN OUTCOME MEASURES: ①The patency rate and blood flow rate of transplanted vessels at different time points. ②Coverage rate of transplanted vascular endothelial cells and vascular intimal thickness.RESULTS:① At 2 weeks and 2 months after common carotid artery transplantation, the patency rate of experimentalside was 100%(5/5)and 60%(3/5), respectively, and that of control side was 40%(2/5)and 0%(0/5), respectively. At postoperative 2 months, the mean blood flow rate in the experimental group was obviously smaller than that in the control group (P ＜ 0.05). At 2 months after inferior caval vein transplantation, the patency rate of experimental group and control group was 83%(5/6)and 50%(2/4), respectively. ②At 2 weeks after common carotid artery transplantation and inferior caval vein transplantation, the coverage rate of vascular endothelial cells in the experimental group was significantly larger than that in the control group, separately (P ＜ 0.05). At 2 months after each transplantation, the vascular intimal thickness in the experimental group was significantly smaller than that in the control group (P ＜ 0.05).CONCLUSION: Seeding of ePTFE prostheses interposition grafts with bone marrow-derived endothelial cells can rapidly accomplish in vivo endothelialization and inhibit intimal hyperplasy; Circulating endothelial cells, as the potential source of endothelial cells, have certain clinical application values.