OBJECTIVE: To prepare chitosan-gelatin/hydroxyapatite (CS-Gel/HA) composite scaffolds, and to investigate the influence of components and preparing conditions to their micromorphology. METHODS: The CS-Gel/HA composite scaffolds were prepared by phase-separation method. Micromorphology and porosity were detected by using scanning electron microscope and liquid displacement method respectively. RESULTS: Porous CS-Gel/HA composite scaffolds could be prepared by phase-separation method, and their density and porosity could be controlled by adjusting components and quenching temperature. CONCLUSION: The study suggests the feasibility of using CS-Gel/HA composite scaffolds for the transplantation of autogenous osteoblasts to regenerate bone tissue.
Objective To review the recent progress of the researches in the field of cartilage tissue engineering, and to discuss the challenges in construction of tissue engineered cartilage. Methods Literature related with cartilage tissue engineering was reviewed and analyzed. Results Some techniques have been appl ied in cl inical. As far as the seeding cells, induced pluripotent stem cells have attracted much more attention. Current strategies of scaffold designing are trying to imitate both component and structure of natural extracellular matrix. Cartilage regeneration through the autologous cell homing technique el iminate the transplantation of exotic cells and has become the hot topic. Conclusion Successful treatment of the damaged cartilage using tissue engineering method will depend on the advances of stem cell technology development, biomimetic scaffolds fabrication and proper appl ication of growth factors.
ObjectiveTo investigate the value of different minimally invasive surgical techniques, stent placement, laparoscopic surgery, and sustained-releasing 5-fluorouracil, in solving intestinal obstruction due to colorectal cancer. MethodsFrom May 2000 to May 2010, total 68 patients with obstructed colorectal cancers in three centers were treated in two ways in terms of the stage: The first, patients with resectable tumors underwent colorectal stent placement as a ‘bridge to surgery’ guided by enteroscope under X-ray. After clinical decompression and bowel preparation, laparoscopic radical resection was performed. The second, patients with unresectable tumors underwent rectal stent placement just for palliation. Sustained-releasing 5-fluorouracil was implanted into the local cancerous intestinal tract through stent walls. ResultsFifty-one of 52 patients underwent laparoscopic radical resection successfully following stent placement, while one failed and died during follow-up 93 d postoperatively. Forty patients with successful laparoscopic surgery were followed up in 3 to 36 months (with an average of 15 months) without tumor planting in the incision, postoperative local recurrence or anastomotic stricture. Fifteen unresectable patients and one high-risk, intolerable patient underwent rectal stent placement and implantation of sustained-releasing 5fluorouracil. During follow-up 3 to 24 months (with an average of 14 months), 11 died, who survived for (350±222) d (range 101-720 d), and 5 were still alive for 3 to 13 months (with an average of 9 months) without intestinal obstruction. ConclusionsLaparoscopic surgery combined with stent placement is an effective and safe procedure for resectable obstructed colorectal cancer. For unresectal obstructed rectal cancer, rectal stent placement combined with sustained-releasing 5-fluorouracil can prolong survival time avoiding colostomy.
OBJECTIVE: To build the trestle of tissue engineering for skin with the collagen. METHODS: The collagen was obtained from the baby cattle hide pretreated by Na2S and elastinase and Protease M, then the collagen was dissolved in 0.5 mol/L acetic acid solution. The collagen was treated with Protease N to minimize its immunogenicity. The resulting collagen could be used to build the trestle of tissue engineering for skin because of good biocompatibility. The collagen molecular weight and structure were analyzed by SDS-PAGE. The bioactivity of trestle was tested in the experiment of the mice wound healing and the cell implantation. RESULTS: The SDS-PAGE result of the collagen treated by Protease M showed the typical spectrum of type I collagen. The built trestle was a collagen sponge matrix in which micropore size was 50-200 microns. It could accelerate wound healing and the implanted fibroblasts could proliferate well. CONCLUSION: The collagen treated by Protease N can get good biocompatibilily and is suitable for building the trestles of tissue engineering for skin with good bioactivity.
Objective To investigate the security and efficiency of endovascular repair for Stanford type B aortic dissection (AD) with severe complications. Methods Between January 2003 and December 2009, 60 patients having Stanford type B AD with severe compl ications were treated, including 39 males and 21 females with an average age of 43.7 years (range, 34-71 years). Severe compl ications included 27 cases of huge hemothorax, 1 case of paraplegia, 7 cases of acute renal failure,10 cases of cel iac trunk ischemia, 10 cases of superior mesenteric artery ischemia, and 5 cases of severe limb schemia. Emergency stent-graft deployment were appl ied in all patients, and 64 stent-grafts were successfully implanted. Results All patients survived and were followed up 3-86 months. Hemothorax disappeared after 28 days to 3 months of operation in all hemothorax patients; renal function returned normal after 1 to 9 days; l imb and visceral ischemia disappeared gradually after 1 to 14 days; and muscular strength of lower limb in the paraplegia patient began to recover after 4 hours of operation. The postoperative CT angiography showed enlarged true lumen and thrombosis in the false lumen. Conclusion Emergency endovascular repair is a safe and effective method to treat Stanford type B AD with severe complications.
Objective
To review the recent advances in the application of graphene oxide (GO) for bone tissue engineering.
Methods
The latest literature at home and abroad on the GO used in the bone regeneration and repair was reviewed, including general properties of GO, degradation performance, biocompatibility, and application in bone tissue engineering.
Results
GO has an abundance of oxygen-containing functionalities, high surface area, and good biocompatibility. In addition, it can promote stem cell adhesion, proliferation, and differentiation. Moreover, GO has many advantages in the construction of new composite scaffolds and improvement of the performance of traditional scaffolds.
Conclusion
GO has been a hot topic in the field of bone tissue engineering due to its excellent physical and chemical properties. And many problems still need to be solved.
Objective To study the mechanism of ectopic osteogenesis of nacre/Polylactic acid (N/P) artificial bone combined with allogenic osteoblasts, and to explore the possibility as a scaffold material of bone tissue engineering. Methods The allogenic- osteoblasts seeded onto N/P artificial bone were co-cultured in vivo 1 week.The N/P artificial bone with allogenic osteoblasts were implanted subcutaneously into the left back sites of the New Zealand white rabbits in the experimental group and the simple N/P artificial bone into the right ones in the control group. The complexes were harvested and examined by gross observation, histologic analysis and immunohistochemical investigation 2, 4 and 8 weeks after implantation respectively.Results In experimental group, the osteoid formed after 4 weeks, and the mature bone tissue withbone medullary cavities formed after 8 weeks; but in control group there was nonew bone formation instead of abundant fibrous tissue after 4 weeks, and more fibrous tissue after 8 weeks.Conclusion N/P artificial bone can be used as an optical scaffold material of bone tissue engineering.
Objective To design a novel stentless porcine aortic bioprosthesis and test the feasibility and its function in vitro after the valve was implanted by a modified method. Methods Six stentless porcine aortic bioprosthesis were divided into two groups according to different implantation, single layer suture group: new improvement stentless porcine aortic bioprosthesis sutured with single layer was implanted; double layer suture group: stentless porcine aortic bioprosthesis developmented by our laboratory used double layer suture was implanted. Each group contained three scales: 23 mm ,25 mm and 27 mm. Analogue ex vivo aortic valve replacement was performed , the feasibility of the new implantation was detected. Effective orifice area, transvalvular pressure gradient and regurgitation ratio were recorded at the cardiac output of 2.0 L/min, 3.5 L/min, 5.0 L/min and 7.0 L/min under the guideline of International Organization for tandardization （ISO）5840. Results The average aortic valve implantation time used for single layer suture and tradition double layer suture were 50 min and 70 min respectively. The transvalvular pressure gradient in the single layer suture group were significantly lower than those in double layer suture group under the flow of 5.0 L/min in 23 mm valve and 27 mm valve （13.51±0.51 mm Hg vs. 14.44±0.99 mm Hg, 7.36±0.19 mm Hg vs. 7.53±0.28 mm Hg；P＜0.01）;and the effective orifice area in the single layer suture group were larger than those in double layer suture group in the same case(1.87±0.06 cm2 vs. 1.76±0.08 cm2, 2.26±0.07 cm2 vs. 2.16±0.05 cm2；P＜0.01). There was no statistically difference in other parameters between both groups. Conclusion The novel design of new improvement stentless porcine aortic bioprosthesis used single layer suture has good hemodynamic characteristics as the nature structure . The modified suture method decrease the implantation time.Nemerical data of the evaluation in vitro show that the difference between single layer suture group and double layer suture group in effective orifice area,transvalvular pressure gradient and regurgitation ratio haveno statistical significance. This experiment is the foundation of the animal and clinical experiment in the future.
