Short-term results in canines of novel stent-graft design for chimney technique in TEVAR

Introduction:Parallel stent-stent grafting is a major endovascular technique used to preserve the supra-aortic branches during thoracic endovascular aortic repair(TEVAR)of aortic pathologies involving the aortic arch.The short-and mid-term results of this technique are satisfactory;however,endoleak remains a major concern.Thus,here we designed a new chimney stent-graft to decrease the endoleak rate.Aim:To testify the feasibility and safety of the new chimney stent-graft system in a canine model.Material and methods:Six Labrador retrievers were used.Pre-operative data were collected and all operations were performed under general anesthesia.The main and chimney stent-grafts were implanted through the abdominal aorta and left subclavian artery approaches,respectively.Completion digital subtraction angiography(DSA)was performed to confirm the immediate outcomes.All dogs were fed separately for 6 months and sacrificed after aortic angiography.The thoracic aorta and the main and chimney stent-grafts were harvested for histopathologic examination.Results:No complications were found in follow-up DSA.All branch arteries were patent.In?ammatory responses were observed around the stent-grafts in 3 experimental animals,and slight hyperplasia was observed in the surrounding tissues compared with the normal vessels.There was no mural thrombus in the stent,endothelial cells were noted on the inner surface of the stent,and thrombus was formed in the outer skirt and gutter area.The histopathologic examinations revealed similar results to those of gross necropsy observations.Conclusions:This study demonstrated the feasibility and safety of the Longuette stent-graft and the first to report a revised stent-graft specific for chimney technique.

Direct-writing Process and in vivo Evaluation of Prevascularized Composite Constructs for Muscle Tissue Engineering Application

Tissue engineered skeletal muscle is expected to treat muscle defects caused by trauma and disease.However,designing and manufacturing thick and complex tissue engineered skeletal muscle requires vascularization to ensure its internal cell viability and nutrient supply in vitro.In this article,we developed a set of Direct-Writing(DW)bio-printing procedure to manufacture a prevascularized composite construct with Human Umbilical Vein Endothelial Cell(HUVEC)and C2C12 cells for muscle tissue engineering application.We put the cells into the construct during the DW process to obtain the prevascularization and intend to promote its vascularization in vivo later.The constructs with cells or without cells were implanted respectively into nude mice back for 3 weeks,after which the mice healthily live for all the time and all the implants are tightly bonded to the host.From immunohistochemical analysis,CD31-positive blood vessels existed in the implanted samples with cells are more substantial than those without cells,but the implanted samples with HUVEC and C2C12 cells have much more number of small blood vessels distributing evenly.Moreover,the implants with cells,especially that with HUVEC and C2C12 cells,are able to get better fusion with the host skin and subcutaneous tissues.Histological analysis demonstrates that our DW-based constructs have the potential to be getting to vascularize the tissue engineered muscle.

A Wireless Video Capsule Endoscopy System: Design and Realization

Wireless capsule endoscopy(CE), an image inspection technique, has been an important advancement in the diagnosis of gastrointestinal(GI) tract diseases. A video capsule endoscopy(VCE) system is analyzed in this study. A complementary metal oxide semiconductor(CMOS) analog image sensor is adopted, and other illumination, communication and energy modules are designed for functional realization. Measuring only φ11 mm ×25 mm, the VCE has a total power consumption of 52.5 m W, which enables it to work continuously for 8 h. The in vivo experiment on a living pig indicates that a clear video with high frame rate of 30 f/s can be obtained.