The mechanical properties of nitinol iliac vein stent (NIVS) have been studied by many scholars at home and abroad, but the study on the mechanical properties of iliac vein stent under different release scales has not been reported yet. Based on the finite element analysis method, the mechanical properties of three self-developed NIVS were studied to reveal the influence of stent diameters (12, 14, 16 mm) and different release scales (80%, 90%) on its strength, fatigue life and vein wall biomechanical properties. With an increases in the release scales, the equivalent elastic strain, fatigue strength safety factors, and vessel wall equivalent stress exhibited a downward trend, while the most stressed cross-section coincided with the arc of stent-connecting rods. Through 30, 60 and 90 days' animal test, a narrowed vascular model was established in the iliac veins of 12 pigs, and the developed iliac vein stents were implanted to comprehensively evaluate the safety and effectiveness of the stent, and at the same time the mechanical properties of stents were verified to provide important reference for the type inspection and clinical trials of follow-up products.
Alloys ; Animals ; Finite Element Analysis ; Iliac Vein ; Stents ; Stress, Mechanical ; Swine

To investigate the cytotoxicity of the homemade peptide cationic liposome CDO14 and its efficacy of RNA interference (RNAi). MTT method was used to determine the cytotoxicity of the liposome to a human lung cancer cell line Luc-A549 that can express luciferase stably. Luciferase siRNA (Luc-siRNA) was transfected into Luc-A549 cells by CDO14. Contents of luciferase in the transfected cells were detected by luminous instrument and contents of total protein in these cells were detected by BCA method. Nude mice were inoculated with Luc-A549 cells in axilla to establish xenograft tumor model. Complexes of Luc-siRNA and the cationic liposomes were injected into the modeling mice via tail vein. Contents of luciferase in the transfected mice were detected by the whole body imaging system. The cytotoxicity of the homemade cationic liposome was similar to that of commercial liposome DOTAP, and lower than that of Lipo2000. The siRNA transfection efficacy mediated by CDO14 was higher than that mediated by DOTAP. The homemade peptide cationic liposome CDO14 is expected to serve as delivery vector in gene therapy because of its low cytotoxicity and high transfection efficiency.
Animals ; Cations ; Cell Line, Tumor ; Fatty Acids, Monounsaturated ; Genetic Therapy ; Genetic Vectors ; Humans ; Liposomes ; Luciferases ; Lung Neoplasms ; Mice ; Mice, Nude ; Peptides ; Quaternary Ammonium Compounds ; RNA Interference ; RNA, Small Interfering ; Transfection

In order to study the efficiency of small interfering RNA (siRNA) transfer mediated by cationic liposome, we used luciferase siRNA to evaluate the gene silencing activity in the Hep-2 cells, which were stably transduced with a luciferase gene. The pDNA transfection was studied, and siRNA arrearage assay was conducted to determine the capability of cationic liposome with siRNA. Different concentrations of siRNA was used to silence luciferase gene' activity, and then the result was examined by microplate reader. Cell viability was analyzed after transfection by MTT assay. The results suggested that Lipofectamine 2000 could transfer the pDNA efficiently, and have strong binding capacity with siRNA. The silencing efficiency of luciferase was obtained with low concentration of siRNA. The cell viability was influenced by RNA interference (RNAi) very slightly, but the cell survival rate decreased with the increase of siRNA concentrations. It was well concluded that by optimizing the experimental conditions, cationic liposome can transfer low concentration siRNA to silence target gene's activity efficiently.
Cations ; chemistry ; Drug Carriers ; Genetic Vectors ; Hep G2 Cells ; Humans ; Lipids ; chemistry ; Liposomes ; chemistry ; Luciferases ; genetics ; RNA Interference ; RNA, Small Interfering ; genetics ; Transfection

BACKGROUND: Dental implants in edentulous patients have been widely discussed, and how to do simple, fast, and economic is working hard. To investigate the clinical effect of immediately loading of two implants supporting a ball-cap attachment-retained implant-supported overdenture in patients with mandibular alveolar ridge atrophy. METHODS: Totally 13 patients of with mandibular alveolar ridge atrophy were selected and treated with ITI implant system and ITI ball-cap attachment system, every case had 2 implants in mandible only and loaded immediately when ball-cap attachments implant-supported overdenture was finished. The applied effect of overdenture was followed-up for 24 months. RESULTS: Every implant was stability, there was not obvious bone absorbed around implant marginal bone, and the overdenture could supply reliable retention and highly masticatory efficiency. Slight mucosal response was found around implants in 3 cases and was cured by maintenance. CONCLUSION: Immediately loading of two implants supporting a ball-cap attachment-retained implant-supported overdenture in patients with mandibular alveolar ridge atrophy was a simple, fast, economic, and feasible mean of dental prosthesis.