Stent implantation plays an significant role in the interventional therapy, mainly with permanent stent, possessing many disadvantages such as restenosis and inflammatory hyperplasia and can thus hardly be used in children and nonmalignant stenosis. Biodegradable stent has theoretical capability to solve these problems and acquires a bright future. Nowadays, with the development of material industry and manufacture craft, biodegradable stent technique has turned up to be mature in last decades. Through the strict animal experiments and prophase of clinic application, satisfactory result has been acquired. We believe that bioabsorbable stent will be widely used in many benign diseases which would be a good supplement for permanent stent in the near future.

Stent implantation plays a more and more important role in the treatment of benign esophageal stenosis. Metal stents are most commonly used in the clinical practice, which can be classified into permanent stents and temporary retrieval stents. Permanent implantation of metal stents is easy to cause complications such as inflammatory hyperplasia, in-stent restenosis, perforation, bleeding, etc. Temporary retrieval stents should be removed with one week after it is implanted in order to avoid esophageal scar tissue repair and in-stent tissue hyperplasia, which can cause difficulty in its removing and produce higher recurrence rate of esophageal restenosis. Clinically, drug-eluting stents have already been used in cardiovascular system procedures, but at present the gastrointestinal drug-eluting stents are still in development and animal experiment stage. Biodegradable magnesium alloy stents have been widely employed in cardiovascular system procedures. With the rapid development of biological engineering materials, drug-eluting magnesium alloy stent has become a hot spot and the frontier in research field. This paper aims to make a comprehensive review about the current research status and prospect of the drug-eluting magnesium alloy stents, focusing on the stent technology, stent molding, coating modification, and the treatment of drug-eluting.

One hundred and seventy one gastric biopsy specimens from the patients undergoing gastroscopic examination from March to November 2010 were reviewed . HE, sliver and immunohistochemistry stains were performed in the specimens; the correlation of histopatholigy and the density and distribution of Helicobacter pylori in gastric mucosa was analyzed .The results displayed that spiral H.pylori mainly appeared on the surface mucus and in the gland lumen of gastric small concave , some were attached to the epithelial cells; coccoid H.pylori appeared within the apical cytoplasmic part of the epithelial cells and in the mucous membrane stroma .The depth of H.pylori infection was correlated with mucosal erosion , inflammation activities and amount of interstitial lymphocytes .The results suggest that spiral H.pylori infection may facilitate the invasive depth of coccoid H.pylori in gastric mucous membrane and the density of H.pylori infection is correlated with the extent and severity of inflammation .

Objective To assess the efficacy and safety of a newly-designed temporary covered cardia stent for the treatment of achalasia in canine models and to investigate the histopathological changes at different points of follow-up time after the stent was removed. Methods The canine achalasia model was created by injecting benzyl-dimethyl-tetradecyl ammonium chloride (BAC) circumferentially into the lower esophageal sphincter (LES) of the dogs. Twenty-four dogs with achalasia were randomly and equally divided into two groups with 12 dogs in each group:control group (using routine esophageal stents) and study group (using newly-designed temporary covered cardia stents). Under fluoroscopic guidance stents were implanted in the esophagus and were taken away from the esophagus 4 days after stent insertion in experimental dogs of both groups. LES pressures and timed barium esophagography (TBE) were performed in all dogs before and immediately after the stenting procedure,as well as at one week,3 and 6 months after the stent was removed. Every three dogs were sacrificed each time at one week,3 and 6 months after the stent was removed. The esophageal cardia was excised and sent for pathological examination. Results All animals well tolerated the stent insertion / removal and the follow-up procedures. No severe complications such as esophageal perforation occurred. Comparison between two groups showed that stent migration occurrence was much lower in study group (n = 1) than that in control group (n = 5). The reduction of LES pressures in study group was more significant in comparison with control group (at 6-month follow-up,P = 0.027). The difference in barium column product (height ? width) between 0-min and 5-min TBE was statistically significant in study group (at 3-month follow-up,P = 0.009). Integrated analysis of multi-comparison for LES pressures among subgroups of each group revealed that the dogs in study group exhibited better outcomes than the dogs in control group. Both proliferating cell nuclear antigen (PCNA) and ?-smooth muscle actin (?-SMA) immuno-staining revealed that the inflammatory reaction reached its peak at 1-month follow-up. Trichrome staining indicated that the collagenous fiber proliferating index inclined to be stable at 3-month follow-up. Conclusion In treating achalasia in canine models the newly-designed temporary covered cardia stent is superior to the routine esophageal stent in respect of safety and efficacy.

Objective To establish a carotid siphon aneurysm model in dogs in order to test the mechanical features of a newly-designed Willis covered stent-graft and to investigate the histological reaction of the stent-implanted vessel during a follow-up period of 12 months.Methods Twenty-four saccular sidewall aneurysms were surgically created in twelve dogs(group A)and 12 carotid siphon aneurysms in another twelve dogs(group B).A Willis stent-graft was implanted in each aneurysm.Angiography was performed immediately after the procedure and 1,3,6 and 12 months after the implantation to investigate the aneurysm isolation,endoleak,stent angulation,and the patency or restenosis of the parent artery.Light and scanning electronic microscopy were used to identify aneurysmai sac thrombi,intima hyperplasia and endothelial progress of the stent-loaded arterial segment.Results In group B,postoperative immediate angiography demonstrated that two aneurysms had mild endoleak and three stents became angulated.Follow-up exam 12 months after the procedure revealed that all previous endoleaks disappeared,one parent artery became occluded and three parent arteries developed mild stenosis(＜50%).In group A.occlusion of parent artery was seen in one and mild stenosis(＜50%)in 2 cases.Electronic microscopy revealed new intima formation in all stents,and all aneurysmal sacs were filled with thrombi.In group B.the endothelialization process was not completed until 12 months after the stent implantation,and a marked correlation existed between endothelial cell arrangement and the hemodynamic orientation.Conclusion It is feasible to treat carotid-siphon aneurysm in dog with a Willis stent-graft.The complete endothelialization of the covered stent in tortuous vessel takes longer time than that in rather straight vessel.

Objective Complicated aneurysms located in the cisternal segment of the internal carotid artery(ICA-CSA)present unique therapeutic difficulties.This study is to discuss the feasibility of the Willis stent-graft in treating complicated ICA-CSA by comparing its effect with that of coiling therapy.Methods Willis covered stents were employed in 19 complicated ICA-CSAs(group A),while coils were used in 17 complicated ICA-CSAs(group B).Follow-up angiography was performed to investigate aneurysm recurrence,endoleak and parent artery(PA)stenosis.Kaplan-Meier curves were constructed to compare the recurrencefree and PA stenosis-free rate in both groups.Results Total exclusion was immediately achieved in 13 ICACSAs and minor endoleaks presented in 5 cases in group A.Total or near-total occlusion was achieved in 7 ICA-CSAs.subtotal occlusion in 8 and partial occlusion in 2 cases in group B after coiling.Acute thrombosis occurred in 1 patient in either group and re-hemorrhage happened in 1 patient after coiling.Follow-up angiography in group A revealed that 16 ICA-CSAs were completely isolated,with two parent arteries showing mild in-stent stenosis.Eighteen months after the procedure,Kaplan-Meier analysis showed that the recurrence-free rate was 93.3%and 50%,while the stenosis-free rate of parent artery was 87.5%and 100% in group A and in Group B,respectively.In group A and group B the clinical neurological symptoms were fully recovered in 9 and 9,obviously improved in 3 and 5,unchanged in 2 and 2,and aggravated in one and 0 patients,respectively.Conclusion The implantation of Willis stent-graft is a feasible endovascular therapy for complicated ICA-CSAs.When the parent artery is very tortuous or when the risk that a main collateral branch may be wrongly covered and occluded is present,the implantation of Willis covered stent can not be taken as the treatment of first choice.

Objective To investigate the efficacy of biphasic insulin aspart 50(BIAsp50)twice daily(bid) versusbiphasichumaninsulin50(BHI50)(bid)plusmetforminonbloodglucosecontrolfollowingastandardmealtest in Chinese patients with type 2 diabetes mellitus(T2DM). Methods A randomized, open-label, 2-sequence, crossover trial for two 4-week treatment periods was conducted in 14 Chines institutes. Eligible subjects inadequately controlled with BHI50(bid)plus metformin were randomized to two sequences in a 1 : 1 ratio(A:BIAsp50-BHI50, B:BHI50-BIAsp50 ) . Standard meal tests were performed at baseline and the ends of two periods within 4 weeks. Primary endpoint was 2h postprandial plasma glucose ( PPG) increment following standard meal test, with insulin dose standardized at 0. 3 IU/kg. Results A total of 161 subjects were randomized into two sequences(81 to sequence A, and 80 to sequence B) and finally analysed. After 4 weeks of treatment, mean 2h PPG increment with BIAsp50 was lower than that with BHI50 [ treatment difference of BIAsp50 vs BHI50: -1. 12 mmol/L ( 95% CI-1. 66,-0. 58), P<0. 01], suggesting superiority of BIAsp50 over BHI50. Incremental area under the curve for PPG(0-2 h)with BIAsp50 was lower than that with BHI50 [treatment difference:-38. 8 mmol·L-1·min-1(95%CI-77. 3,-0. 26), P=0. 049], as was the mean 2h PPG [treatment difference:-0. 58 mmol/L(95% CI -1. 13,-0. 03), P=0. 040]. The FPG value with BIAsp50 was higher than that with BHI50 [treatment difference:0. 52 mmol/L(95%CI 0. 18, 0. 86), P=0. 003]. The rate of nocturnal hypoglycemia with BIAsp50 was lower than that with BHI50(1. 13 vs 2. 86 events per subject year, P<0. 01). Conclusion In patients with T2DM inadequately controlled with BHI50 plus metformin, BIAsp50 was proven to be well-tolerated with improved postprandial glucose control compared with BHI50.

Objective To study the mechanical properties and degradation behavior of biodegradable silicon-covered magnesium alloy stent in vitro,to investigate the technical feasibility of its implantation into rabbit esophagus and to observe the tissue reaction in vivo.Methods The mechanical compression recovery properties and the degradation behavior of biodegradable silicon-covered magnesium alloy stent were tested in vitro.A total of 30 healthy Holland rabbits were randomly divided into silicon-covered magnesium alloy stent group (n=15) and control group (n=15).For rabbits in the silicon-covered magnesium alloy stent group fluoroscopy-guided insertion of the stent into the lower third segment of esophagus was conducted,while for rabbits in the control group no intervention was adopted.One,2 and 4 weeks after the implantation of the stent,esophagography was performed for all rabbits of both groups,and each time every 5 rabbits from both groups were sacrificed,the specimens were collected and sent for histological examinations.Results In vitro test indicated that biodegradable silicon-covered magnesium alloy stent had good flexibility and elasticity,and in phosphate-buffered saline with pH 4.0 or pH 7.4 it degraded more slowly than bare magnesium alloy stent.In vivo test showed that the stent implantation could be well tolerated by all experimental rabbits.Before stent insertion the esophageal diameter was(9.2±0.8) mm,and at one,2 and 4 weeks after stent insertion the esophageal diameters were (9.7±0.7) mm,(9.6±0.8) mm and (9.6±0.5) mm respectively (P＞0.05).In the silicon-covered magnesium alloy stent group,stent displacement occurred in 6 rabbits in one week (n=l),2weeks (n=1) and 4 weeks (n=4).After stent implantation,the tissue reactions such as esophageal wall injury,collagen deposition,etc.were not obviously different from those in the control group (P＞0.05).Conclusion It is technically feasible to insert silicon-covered magnesium alloy stent into the rabbit's esophagus,the stent can provide sufficient support for at least 2 weeks,the stent displacement rate is low and acceptable,and no severe esophageal wall injury and collagen deposition are observed.

Objective:To evaluate the image quality (IQ) of 18F-fluorodeoxyglucose (FDG) PET/CT imaging and identify its influenfial factors in diabetes mellitus (DM) and non-DM patients with coronary artery disease (CAD). Methods:A total of 196 consecutive CAD patients (174 males, 22 females, 68 DM; age: (57±10) years) in Beijing Anzhen Hospital between June 2016 and February 2018 were retrospectively analyzed. All patients underwent 18F-FDG myocardial PET/CT imaging. The standardized fasting+ oral glucose loading (OGL) and intravenously injection of insulin protocol was performed. According to the FDG uptake by myocardium, background activity in blood and other visceral organ nearby the heart, the IQ was visually evaluated and scored by 0-4. Zero-two was considered as good IQ, 3-4 was regarded as poor IQ. Patients were divided into three groups: group 1 (non-DM+ good IQ), group 2 (DM+ good IQ), group 3 (DM+ poor IQ). Factors which may affect IQ were analyzed, which including OGL, the injection dose of insulin, fasting blood glucose (FBG), peak blood glucose (PBG), blood glucose (BG) level at 18F-FDG injection (BG injnection), BG increasing rate ((PBG-FBG)/FBG, %), and BG decreasing rate ((PBG-BG injection)/PBG, %). One-way analysis of variance, Spearman correlation analysis and logistic regression analysis were used for data analysis. Results:There were significant differences ( F values: 13.074-38.371, all P<0.05) of FBG, PBG, OGL, BG decreasing rate and the injection dose of insulin among group 1 ( n=132, 67.3%), group 2 ( n=53, 27.1%), group 3 ( n=11, 5.6%). All those parameters, except for OGL, were positively correlated with FDG PET/CT IQ ( r s values: 0.142-0.262, all P<0.05). OGL was negatively correlated with IQ ( r s=-0.324, P<0.05). Logistic regression analysis showed that FBG (odds ratio ( OR)=0.687, 95% CI: 0.633-0.746), PBG( OR=0.786, 95% CI: 0.746~0.829), BG injection( OR=0.631, 95% CI: 0.595-0.716), OGL( OR=0.897, 95% CI: 0.873-0.922), the injection dose of insulin( OR=0.680, 95% CI: 0.618-0.748) were predictive factors (all P<0.01) for good IQ in all patients. For DM patients, OGL was the only predictive factor for good IQ( OR =0.940, 95% CI: 0.904-0.960; P<0.01). Conclusions:FBG, PBG, BG injection, OGL, the injection dose of insulin can predict IQ for all patients with CAD. For DM patients with CAD, OGL is the only predictive factor for good IQ. A good IQ of 18F-FDG PET/CT could be obtained in majority of CAD patients, with the standardized fasting + OGL and intravenously injection of insulin protocol and adjust according to the personal status, and prevent the hypoglycemia from happening.

Objective: To establish the in vitro porcine gastric model of submucosal eminence lesion and to evaluate its application to endoscopic submucosal dissection(ESD). Methods: Silicone rubber impression materials and steel balls with diameters of 1 cm, 2 cm, and 3 cm were used to make three pairs of spherical cavities. And then raw ground beef was put into spherical cavities and boiled for 20 minutes to make spherical mass models. Six isolated porcine stomach with esophagus and duodenum were selected. The mass models with diameters of 1 cm, 2 cm and 3 cm were imbedded respectively into the submucosa of fundus, body, and antrum of porcine stomach through the incision on serosal layer. The submucosal masses were observed by endoscopy and endoscopic ultrasonography and ESD was performed. Results: A total of 18 mass models were constructed in 6 porcine stomachs, of which 17 models were successfully established and 1 failed. Typical endoscopic characteristics of gastric submucosal eminence lesions were found in 17 models. Endoscopic ultrasonography showed that these models originated from submucosal layer and demonstrated mixed echo. There were no significant differences between mucosa of lesions and that of surrounding areas. ESD was successfully performed in the porcine gastric models of submucosal eminence lesions, and all models were not broken or detached. Conclusion The in vitro porcine gastric model of submucosal eminence lesions can well replicate disease status and provide a suitable model for study on endoscopic therapy of submucosal eminence lesion and training of endoscopists.