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.

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.

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 compare the clinical efficacy of transdorsal-to-plantar (TDP) or transplantar-to-dorsal (TPD) retrograde endovascular angioplasty in treating below-the-knee arterial occlusion diseases, and to compare it with conventional anterograde endovascular angioplasty. Methods A total of 96 patients with below-the-knee arterial occlusion diseases (112 diseased lower extremities in total), who were admitted to authors’ hospital during the period from Oct. 2009 to July 2011 to receive conventional anterograde endovascular angioplasty, were enrolled in this study. The clinical data were retrospectively analyzed. Among the 112 diseased lower extremities, conventional anterograde endovascular angioplasty failed in 27, and TDP or TPD retrograde endovascular angioplasty had to be carried out. A total of 71 patients (85 diseased lower limbs) were successfully treated with conventional anterograde endovascular angioplasty (routine group), while 20 patients (22 diseased lower limbs) were successfully treated with retrograde endovascular angioplasty (retrograde group). The preoperative ankle-brachial index(ABI), the coronary angiography-based thrombolysis in myocardial infarction (TIMI) flow score, the dorsal or plantar arterial pulse score, the postoperative limb salvage rate and target vessel patency rate were calculated, and the results were compared between the two groups. Results The technical success rate in the retrograde group and the routine group was 75.9% and 74.0%respectively (P>0.05). Preoperative ABI value of the retrograde group and the routine group was 0.55± 0.21 and 0.56±0.14 respectively, after the treatment which increased to 0.93±0.19 and 0.89±0.18 respectively (P>0.05). Preoperative TIMI score of the retrograde group and the routine group was 0.1 ±0.5 and 0.8 ±0.8 respectively, which significantly increased to 2.5±0.6 and 1.8±0.8 respectively (P<0.000 1). In the retrograde group, the blood flow perfusion of the distal foot tissue was improved. The primary target vessel patency rate at 12 months and 24 months after the treatment in the retrograde group and the routine group were 63.6%(14/22), 45.5%(10/22) and 52.9%(45/85), 37.6%(32/85) respectively (P>0.05). Twenty-four months after endovascular angioplasty Kaplan-Meier analysis indicated that the limb salvage rate of the retrograde group and the routine group was 95.5%and 96.5%respectively (P>0.05). Conclusion Compared with conventional anterograde endovascular angioplasty for the treatment of below-the-knee arterial occlusion diseases, retrograde endovascular angioplasty via TDP or TPD path can immediately improve the blood flow with obvious improvement of ABI score, primary target vessel patency rate as well as the limb salvage rate. Therefore, retrograde endovascular angioplasty should be regarded as an effective supplementary technique when anterograde angioplasty fails.

Objective To study the defects of bone marrow-derived endothelial progenitor cells (EPCs) in number ratio and biological abilities (proliferation, adhesion and migration) in diabetic rats. Methods (1) Establishment of diabetic rat model:1%STZ solution was quickly injected into the abdominal cavity of the male SD rats with the dose of 60 mg/kg. (2). Isolation, culture and identification of bone marrow-derived EPCs in diabetic and normal rats. Bone marrow mononuclear cells were isolated from diabetic and normal rats by density gradient centrifugation methods and cultured by EGM-2 MV medium. The cells were identified by morphological observation, FITC-UEA-1 binding and Dil-Ac-LDL uptake assay, and fluorescent immunocytochemistry was used for detection of CD34 , CD133 and VEGFR-2 expression. CCK-8 method and Transwell kit method were used to determine biological activities of EPCs. Results (1) When cultured in vitro, both bone marrow-derived EPCs in diabetic and normal rats were fusiform in shape, the cells snuggled up to the wall. The expression of CD34, CDl33, VEGFR-2 could be detected in these cells, and the cells could uptake Dil-Ac-LDL and bind FITC-UEA-1, which proved that these cells were EPCs. (2) No significant difference in the number of EPCs derived from bone marrow existed between diabetic rats and normal rats, but the proliferation ability, migration ability and adhesion ability of bone marrow-derived EPCs in diabetic rats were obviously lower than those in normal rats. Conclusion The number of bone marrow-derived EPCs in diabetic rats is not obviously different from that in normal rats, but the biologic activity of EPCs derived from bone marrow in diabetic rats is degraded, which is manifested as weakened abilities of the proliferation, adhesion and migration.

Objective:To investigate the variation characteristics and influencing factors of HIV/AIDS subtypes in Wuxi city of Jiangsu Province from 2014 to 2016.Methods:HIV/AIDS population in Wuxi city in 2014 was selected as the research object, and the HIV molecular epidemiology and follow-up study were carried out. Collect epidemiological information, extract DNA from blood samples, amplify pol gene fragment by nest-PCR and sequence, use ChromasPro 1.6 software and MEGA 7.0 software to construct the HIV-1 sequence database, and use FastTree2.1.10 software to construct the phylogenetic tree to confirm the subtype; in 2016, the same population was followed up, and the HIV subtype variation was analyzed, and the influencing factors of subtype variation were explored by multivariate logistic regression. Results:A total of 612 HIV/AIDS cases in 2014 and 2016 were collected. The age of the subjects was mainly 30 years old or above (85.46%, 523/612), and the proportion of people over 50 years old was higher (228/612, 37.25%). The main route of transmission was homosexuality, accounting for 49.67%. A total of 1224 samples were detected and CRF01 _ AE、CRF07_ BC、B、CRF08_ BC、CRF67_ 01B、CRF55_ 01B、CRF68_ 01B, 7 subtypes of HIV-1 and 5 unique recombinant types (URFs) was detected. CRF01_ AE and CRF07_ BC was still the main genotype in Wuxi, Jiangsu Province, accounting for 66.75%. There were 29 cases (3.56%) of URFs recombinant strains. During 2014-2016, the variation rate of subtypes was 14.63%, and the most common variation was CRF01_ AE changes to CRF07_ BC(13.95%). Marital status (OR=0.363, 95% CI: 0.137-0.964) and baseline CD4 level (OR=0.414, 95% CI: 0.192-0.891) were associated with subtype variation.Conclusions:The HIV-1 subtypes of HIV/AIDS patients in Wuxi city are diverse and complex, the proportion of recombinant subtypes is rising, the URFs that are difficult to determine the genotype increase significantly, and the variation rate of HIV-1 subtypes among HIV/AIDS infected people is high. It is necessary to strengthen the monitoring of HIV-1 subtypes.

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:The purpose of this paper is based on the concept of enhanced recovery after surgery, to discuss the timing of taking food and water in knee arthroplasty patients, as well as its feasibility and safety, so as to improve the quality of quality nursing services.Methods:The 226 knee arthroplasty patients in Luoyang Orthopedic-Traumatological Hospital (Henan Provincial Orthopedic Hospital) from September 2020 to November 2021 were selected and divided into a control group and a experimental group using the random number table method, with 113 cases in each group. The control group adopted a conventional postoperative feeding management method; the experimental group adopted the early and timely feeding management method after comprehensive assessment. The data were compared between the two groups, including the incidence and severity of postoperative nausea and vomiting within 6 h and from 6 to 24 h after surgery , the incidence of thirst and hunger at 2 h, 4 h and 6 h postoperatively, and the comfort level.Results:The incidence of postoperative nausea and vomiting was lower in the experimental group [19.5%(22/113), 13.3%(15/113)] than in the control group [32.7%(37/113), 23.9%(27/113)] within 6 h and from 6 to 24 h after surgery, and the severity (21 cases of gradeⅠ, 10 cases of gradeⅡand 6 cases of grade Ⅲ) was also lower than in the control group (17 cases of gradeⅠ, 29 cases of gradeⅡand 18 cases of grade Ⅲ), and the differences were all statistically significant ( χ2 = 5.16,4.21, Z = -2.72, P<0.05). The incidence of thirst were lower in the experimental group [14.2%(16/113), 8.0%(9/113), 2.7%(3/113)] than in the control group [26.5%(30/113), 29.2%(33/113), 40.0%(35/113) at 2 h, 4 h and 6 h postoperatively, and the incidence of hunger at 4 h and 6 h postoperatively [11.5%(13/113), 8.0%(9/113)] were lower than in the control group [32.7%(37/113), 34.5%(39/113)], with statistically significant differences ( χ2 values were 5.35 to 32.39, all P<0.05). The postoperative comfort scale scores of physiological (31.04 ± 1.00) and psychological (33.50 ± 1.45) were higher in the experimental group than in the control group (27.46 ± 1.78) and (31.37 ± 1.29), and the differences were statistically significant ( t values were -102.36 to -66.26, all P<0.05). Conclusions:Early postoperative feeding management at the right time reduces the incidence and severity of postoperative nausea and vomiting inknee arthroplasty patients. In addition, it can also reduce the incidence of thirst and hunger, and improve patients′ postoperative physiological and psychological comfort, which has a facilitating effect on achieving rapid recovery of patients.