RESUMO
Objective To develop a magnetic anastomosis device for infrahepatic inferior vena cava and verify its feasibility and safety in rat models. Methods According to the anatomical characteristics of rat inferior vena cava, a magnetic device suitable for end-to-end anastomosis of infrahepatic inferior vena cava was designed and manufactured. The device consisted of the inner and outer rings. The inner ring was a coated neodymium-iron-boron magnetic ring, and the outer ring was made of polyetheretherketone by 3D printing. Ten fine holes are evenly distributed on the outer ring, of which 5 fine holes were used to load the fine needles, and the other 5 fine holes were mutually connected with the fine needles of the contralateral anastomosis ring during anastomosis. The outer ring was uniformly loaded with fine needles and then bonded with the inner ring to form a magnetic anastomosis complex. Bilateral ends of vessels passed through the anastomosis ring and were fixed to the fine needles, and then end-to-end vascular anastomosis was performed by mutual attraction of two magnetic anastomosis rings. Twenty SD rats were selected and received end-to-end anastomosis of infrahepatic inferior vena cava with magnetic anastomosis device. The time of vascular occlusion, postoperative survival, postoperative anastomotic patency, gross observation and histological examination of anastomotic stoma were analyzed. Results All rats successfully completed end-to-end magnetic anastomosis of the infrahepatic inferior vena cava, and the time of vascular occlusion was 4~6 min. One rat died at 10 d after operation, and the other rats survived within postoperative 2 months. The patency rates of anastomotic stoma in surviving rats at postoperative 1 d, 3 d, 1 month and 2 months were 100%, 100%, 95% and 95%, respectively. At 2 months after operation, no obvious displacement and angulation of the anastomosis device were seen. No signs of corrosion and cracking of the anastomosis rings were observed. No evident hyperplasia and edema of surrounding tissues were noted. Bilateral ends of vessels were completely healed, and no obvious stenosis or thrombosis was found at the anastomotic stoma. Histological examination showed high continuity of bilateral vascular walls of anastomotic stoma, the inner surface of anastomotic stoma was covered by endothelial cells, and no thrombus or fibrous tissue was attached. Conclusions It is safe and feasible to utilize the self-designed magnetic anastomosis device to perform end-to-end magnetic anastomosis of infrahepatic inferior vena cava in rat models.
RESUMO
According to the principle of immunomagnetic separation, a novel high-efficient immunomagnetic isolator termed as CMSI 100 for the purification of human CD34 + hematopoietic cells was designed and successfully developed. To do this , neodymium iron boron having magnetic properties superior to any other permanent magnet materials was selected as the key parts of CMSI 100 isolator. The core of the magnet assembly was constructed by sandwiching mild steel bars between 4 pieces of magnet bars of neodymium iron boron. Each piece of magnet bars must be limited to the specifications of 3.5cm?2.0cm?0.3cm so that 2 700 gauss magnetic attractive force could be exerted at the magnet surface. Otherwise magnetic field above the surface of the magnet assembly is either very stronger or weaker, both of which are not beneficial to the enrichment of CD34 + hematopoietic cells. With CMSI 100 immunomagnetic isolator, more than 90% purity and over 95% viability of CD34 + hematopoietic cells could be obtained. These data indicate that CMSI 100 immunomagnetic isolator is as good as the internationally used Isolex TM 50 made by Baxter Company in USA.