A Nanostructured Degradable Ureteral Stent Fabricated by Electrospinning for Upper Urinary Tract Reconstruction.

A degradable polycaprolactone(PCL)/poly(lactic-co-glycolic acid, LA:GA = 80:20) (PLGA) ureter tubular stent was fabricated by electrospinning. The structure and properties of the stents were investigated by the mechanical property testing, scanning electron microscopy (SEM), degradability test in vitro and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The stent was transplanted to the dorsal muscle of rabbit to evaluate its tissue compatibility. It was shown that the stent has the nano-structure. The mechanical test showed that with the increase in PCL concentration, the mechanical properties of the stent gradually increased, and it could meet the demands of a urethral stent. The collapse time of different concentration of PCL/PLGA (5%, 15%, and 25%) was 28, 42, and 56 days, respectively. These results provide strong evidence that the degradation time can be increased with the increase in PCL concentration. The results of the MTT assay show that the PCL/PLGA stent had no cytotoxicity. In muscle implantation tests, acute tissue reactions due to operation trauma were seen in all specimens at 1 week. After four weeks, the number of inflammatory cells had decreased significantly. Only a few inflammatory cells were seen in the PCL/PLGA stent group after 12 weeks, and the foreign body reaction was more severe in the control group. Animal orthotopic transplantation experiments of these ureteral stents will be done to evaluate its degradable model and tissue compatibility.

[CLINICAL EFFICACY OF MODIFIED POLYTETRAFLUOROETHYLENE PROSTHESIS RHINOPLASTY].

OBJECTIVE: To explore the clinical efficacy of modified polytetrafluoroethylene (PTFE) prosthesis rhinoplasty for correction of low nose and short columella. METHODS: Between August 2012 and August 2015, modified PTFE prosthesis rhinoplasty was used to correct low nose and short columella in 52 patients. There were 4 males and 48 females, aged 19 to 45 years (mean, 27 years). Primary rhinoplasty was performed in 47 cases; secondary rhinoplasty was performed in 5 cases, and it was 12-18 months from the first operation (mean, 15 months). During operation, a scaly sag ventral side was made by carving and moving cap shaped nose prosthesis was prepared, and nasal dorsumnasal columella prosthesis covered by tension-free flap was designed. At pre-operation and last follow-up, Image ProPlus 6.0 software was used to measure the nose length, nose depth, nose tip width, nostril/nose tip, nasolabial angle, and nasal tip rotation for evaluation of external nose shape correction; and ultrasound was used to measure the alar cartilage angle, alar two vertex distance, and nose tip to vertex distance for evaluation of internal soft tissue changes; the prosthesis position was observed by CT scan at 12 months. RESULTS: All incisions healed by first intention, with no complications. All patients were followed up 7-36 months (mean, 20.4 months). At 12 months after operation, CT scans showed that prosthesis located in the middle of the nose and above nasal bone, septal cartilage and crus mediale cartilaginis alaris majoris in 45 patients; no prosthesis displacement was observed. At last follow-up, image measurement and ultrasound results showed external nose shape parameters (except nostril/nose tip) and internal soft tissue structures were significantly improved when compared with preoperative values (P<0.05). CONCLUSIONS: Modified PTFE prosthesis rhinoplasty can effectively correct low nose and short columella, with small surgical trauma and good appearance.