Objective To explore an effective method to culture and purify porcine keratinocytes, to observe the morphological characteristics of porcine keratinocytes growing on acellular amnion and to offer the experimental basis for that the amnion is used for tissue engineering. Methods The primary porcine keratinocytes were cultivated with DKSFM(Defined keratinocyteSFM) containing 10% fetal bovine serum (FBS). The second passage porcine keratinocytes were cultivated with the medium of DKSFM containing different concentrations of FBS. Because of the speciality that keratinocytes stick to flask fast, we purified the keratinocytes by 0.02% EDTA and 005% trypsin step by step. The second passage keratinocytes were seeded on amnion, the keratinocytes/amnion composites were observed by dye directly, histopathology and immunohistochemical staining. Results The proliferation of the primry porcine keratinocytes cultured with the medium ofDKSFM containing 10% FBS was fast and the morphological characteristics were good. The cultivated porcine keratinocytes expanded to 60%70% of the total area of the bottle of the flask after 5 days. The proliferation of the second passage porcine keratinocytes cultivated with the medium that DKSFM containing 5% FBS was faster than the second porcine keratinocytes cultured with the medium of DKSFMcontaining 10% FBS, or DKSFM without FBS. The proliferation of the second passage porcine keratinocytes cultivated with DKSFM without FBS was the slowest one among the 3 medium. The porcine keratinocytes that were purified by 0.02% EDTA and 005% trypsin step by step were got with high pure. After the keratinocytes were cultivated on the surface of amnion 12 days, the keratinocytes form a single layer on the surface of amnion and the cells were polygong and arranged like slabstone. After 14 and 16 days,the cells contacted more closely. But at 16 days after the cells were seeded, some of the cells got aging. Conclusion To culture primary porcine keratinocytes with the medium that DKSFMcontaining 10% FBS and to cultivate the second passage with the medium containing 5% FBS, the proliferation of porcine keratinocytes are faster. The method that purify the porcine keratinocytes is effective. Acellular amnion offers excellent bioscafold to support keratinocytes to adhere and grow. After the porcine keratinocytes are cultivated on the surface of the acellular amnion 12 days, the morphologic characteristics are better than that of other groups.
Forty-eight cases of multi-structural defects of hands were primarily repaired or reconstructed from July 1989 to 1997. The structural defects included: the defects of radial or ulnar aspect of hands involving fingers and skin, multiple fingers defects and the fingers and skin defects of whole hand. In this series, there were 32 males and 16 females with age ranged from 17 to 46 years old. The composite tissue grafts were obtained from wrap-around flap or 2nd toe skin flap of the foot. The result showed that composite 108 tissues transplantations, or 48 cases, were all survived. After a follow-up of 38.5 months (ranged from 5 months to 6 years), the grasp, pinch and opposition function of the reconstructed finger were restored, the two-point discrimination sensation was 4 mm-12 mm. Most of the patients had resumed their original works. So that the primary repair of multi-structural defects of hands by composite tissues transplantation was feasible and valuable, but thorough debridement and skilled microsurgecal technique were required.
Objective To evaluate the cl inical effect and the pathological characteristics of acellular allogeneic dermal matrix in repairing unstable burn scar. Methods From January 2007 to June 2008, 19 cases of unstable burn scars (24 parts) were treated, including 16 males (20 parts) and 3 females (4 parts) with a median age of 27 years (range, 3-58 years). Theinjury was caused by flame (14 cases, 18 parts), electricity (4 cases, 5 parts), and hot water (1 case, 1 part). The unstable burn scars located on hands (8 cases), forearms (2 cases), thighs (3 cases), legs (2 cases), feet (2 cases), chest (1 case), and abdomen (1 case). Scar formed for 3 months to 1 year. The area of defect varied from 7 cm × 5 cm to 22 cm × 15 cm after scar removal. Defects were covered with acellular allogeneic dermal matrix and autogenous spl it-thickness skin graft. At 6-18 months after operation, the pathological observations of the epidermis, the basal membrane, and structural components of the dermis were done. Results All wounds healed by first intention. Scar ulcer disappeared completely in 18 cases and the composite skin grafts all survived. Some bl isters occurred in 1 case and were cured after dressing changing. All patients were followed up 10 months to 2 years (18 months on average). The grafted-skin was excellent in the appearance, texture, and elasticity. The function recovered well. Only superficial scar was observed at skin donor sites. Pathological observation showed that the epidermis and the basal membrane of the skin grafts were similar to that of normal skin, and no significant difference was found in newly capillaries between them. Collagen fibers arranged regularly, and there were few inflammatory cells in the matrix. Conclusion Acellular allogeneic dermal matrix with autogenous spl it-thickness skin graft may effectivly repair the wound after removing the unstable burn scar, and its structure is similar to that of normal skin.
Objective To evaluate the biomechanicalproperties and structuralcharacteristics of various composites of partially decalcified allogenic bone matrix gelatin and bone cement at different ratios. Methods According to Urist method, partially decalcified allogenic bone matrix gelatin was prepared and mixedwith bone cement at different ratios of 0, 400, 500, and 600mg/g. Then the comparisons of these composites were performed in microstructure, ultimate compression strength and ultimate bending strength properties. Results The electronic microscope showed that the bone particles and bone cement were distributed evenly in the composite, irregularly connecting by multiple points; with the increase ofbone particles and decrease of bone cement in the composite, there were more and more natural crevices, varying from 100 μm to 400 μm in width, in the biomaterials. Of all the composites with the ratios of 0, 400,500, and 600 mg/g, the measurements of ultimate compression strength were (71.7±2.0) MPa, (46.9±3.3) MPa, (39.8±4.1) MPa, and (32.2±3.4) MPa, respectively; and the measurements ofultimate bending strength were (65.0±3.4) MPa, (38.2±4.0) MPa, (33.1±4.3) MPa and (25.3±4.6) MPa, respectively. Conclusion The compositeof partially decalcified allogenic bone matrix gelatin and bone cement has a good biomechanical property and could be easily fabricated and re-shaped, which make it available to be used clinically as an idea bone graft biomaterial.
Ceramiclike xenogeneic bone (CXB) was obtained from the fresh bone of pig ribs being treated by physical and chemical methods to deprive of its organic substance. The CXB possessed the same natural porous network system as that of the human. The CXB was cultured with the bone marrow stromal cells of rabit. When the marrow cells had integrated with the CXB, thus a new material was obtained. (CXB-BM), and was implanted sacro-spinal muscle of rabbit. The specimens were observed under phase microscope, light microscope and electronic scanning microscope. The results showed that: at the 2nd week after the implantation of CBX-BM composite material there began the new bone formation, and the rate of bone formation was increased with time. There was evident new bone formation after 24 weeks. The process of the new bone formation were quite similar to the composite graft of HAP red autogenous and marrow, but the former degraded faster and formed typical cancellous structure earlier. There was no new bone formation when CXB was implanted alone in the control. Both the mechanism of osteogenetic potential and its clinical application were discussed.
The stiffness of an ideal fracture internal fixation implant should have a time-varying performance, so that the fracture can generate reasonable mechanical stimulation at different healing stages, and biodegradable materials meet this performance. A topology optimization design method for composite structures of fracture internal fixation implants with time-varying stiffness is proposed, considering the time-dependent degradation process of materials. Using relative density and degradation residual rate to describe the distribution and degradation state of two materials with different degradation rates and elastic modulus, a coupled mathematical model of degradation simulation mechanical analysis was established. Biomaterial composite structures were designed based on variable density method to exhibit time-varying stiffness characteristics. Taking the bone plate used for the treatment of tibial fractures as an example, a composite structure bone plate with time-varying stiffness characteristics was designed using the proposed method. The optimization results showed that material 1 with high stiffness formed a columnar support structure, while material 2 with low stiffness was distributed at the degradation boundary and inside. Using a bone remodeling simulation model, the optimized bone plates were evaluated. After 11 months of remodeling, the average elastic modulus of callus using degradable time-varying stiffness plates, titanium alloy plates, and stainless steel plates were 8 634 MPa, 8 521 MPa, and 8 412 MPa, respectively, indicating that the use of degradable time-varying stiffness plates would result in better remodeling effects on the callus.
Objective To evaluate the advantages and disadvantages of vascularized free peroneal composite flaps for reconstruction of oral and maxillofacial defects. Methods From November 1999 to December 2002, 28 cases of oral maxillofacial defects were reconstructed with vascularized free peroneal composite flaps, with fibulacutaneous flap in 21 cases and with fibulamyocutaneous flap in 7 cases. Three cases received insertion of dental implants into the fibula flap. The flap size was 3.0 cm×5.5 cm to 8.0 cm ×12.0 cm; the fibula length was 5.5 cm to 16.0 cm. Results Of the 28 flaps reconstructed, 24 survived,3 necrosed partially and 1 necrosed completely. All the 5 implants survived andachieved good bone integration in 3 cases. Twenty-six cases were followed up 1-36 months with an average of 18.5 months, the facial appearance and the vocal function were satisfactory in 23 cases. Conclusion Vascularized peroneal flap has many advantages and is one of the optimal flaps for reconstruction of oral maxillofacial defects.
Objective To evaluate midterm and longterm clinical outcome of bilateral internal mammary artery composited Y grafts for coronary artery bypass grafting (CABG)， analyze risk factors for late death ，and to improve surgical results. Methods Between January 2000 and May 2004, One hundred and sixtyfive patients underwent bilateral internal mammary artery grafts for CABG, The clinical data, postoperative complications and survival results were retrospectively reviewed and analyzed. The preoperative and postoperative cardiac function was compared. All factors that may have affected the survival were analyzed by logistic regression, to identify significant variables associated with late death. Results Total 561 anastomosis sites of internal mammary arteries were completed with each patient received an average of 3.4 grafts. There were no perioperative deaths. There were 16 patients with postoperative complications including recurrent angina, myocardial infarction, low cardiac output syndrome, sternal infection and so on. All patients were treated conservatively without reoperation. One hundred sixty patients（97%）were followed up of 5.6±1.2 years, there were 23 late deaths including 10 patients of cardiac related death in which 3 had recurrent myocardial infarction, 4 heart failure, and 3 arrhythmia; 13 patients of nocardiac related death in which 4 upper gastrointestinal hemorrhage, 3 cancer and 6 uncertain cause. 25 patients had major cardiac related events including recurrent angina 18, myocardial infarction 4, repeated revascularization 3. Left ventricular ejection fraction [CM(159mm]was significantly improved as compared with that before operation（54%±6% vs. 43%±12%, Plt;0.05）. The 1-, 3-, 5-year actuarial survival rates and eventfree rates were 98.2%±0.3%, 96.2%±0.5%, 90.5%±1.9% and 95.5%±1.2%, 91.3%±2.1%, 86.6%±1.5%, respectively. According to statistical analysis, univariate analyses had proved that advancing age＞65 years，diabetes，ejection fraction(EF) less than 30%，the New York Heart Association (NYHA) class Ⅲ/Ⅳ, and low cardiac output syndrome required placement of the intraaortic balloon pump were predictors associated with hospital major adverse cardiac events (Plt;0.05). Those variables entered into the logistic regression model and found to be independent predictors associated with increased late cardiac death included advancing age ＞65 years(OR=11.6), diabetes (OR=21.4), EF less than 30%(OR=37.5) and NYHA class Ⅲ/Ⅳ(OR=40.2). Conclusion Patients receiving bilateral internal mammary artery composited Y grafts have better longterm survival and reduced cardiac related events. Independent risk factors for late death are NYHA function class Ⅲ/Ⅳ, EF less than 30%, diabetes and advancing age ＞65 years.
Objective To investigate the application and effect of the crossbridge vascular anastomosis free flap transplantation for tissue defects of extremities. Methods From May 1982 to November 2005, 110 cases of tissue defects of extremities were treated with cross-bridgevascular anastomosis free tissue transplantation. Of 110 patitents, 80 were male and 30 were female with a median age of 30 years(5 to 54 years). Tissue defects were caused by traffic accidents (59 cases), machine injuries (32 cases) and mangled injuries (19 cases). The locations were the forearms in 2 cases and the legs in 108 cases. And 69 cases had simple soft tissue defects, 6 cases had simple bone defects, and 35 cases had complicated defects. The length of bone defectranged from 5 cm to 19 cm and the area of soft tissue defect ranged from 6 cm×10 cm to 15 cm×35 cm. The graft tissue included latissimus dorsi musculocutaneous flap, vastus anterolateral flap,cutaneous fibula flap, osseous fibula flap, and cutaneous iliac flap. The cross-bridge of the two lower extremities wasperformed in 106 cases, the cross-bridge of the two upper extremities in 2 cass, and the crossbridge of the upper-lower extremities in 2 cases. The compoite tissue transplantation was used if the graft tissues were two or more. The wounds of donor site was directly sutured in 67 cases, and partly sutured with skingrafting in 43 cases. Results Vascular crisis occurred in 9 cases. Vascular crisis was relieved in 5 cases and grafting tissues was survival after exploring the vessel; 4 cases failed. The graft tissue was survival in 101 cases, and the survivalrate was 96.4%. The follow-up time was 4 months to 22 years with an average of 6.3 years. Graft bone healed and mean healing time was 4 months. The flap appearance was satisfactory and extremity function was restored to normal. One case became necrosis in the edge of the flap and cured by debridement, dressing and skingrafting, the other got primary healing at 2-3 weeks after operation. Conclusion The application of the cross-bridge vascular anastomosis free tissue transplantation for tissue defects of extremities is an effective method, when extremities have no vessel anastomosed.
The poor mechanical property and vulnerability to bacterial infections are the main problems in clinic for dental restoration resins. Based on this problem, the purpose of this study is to synthesize silver-titanium dioxide (Ag-TiO2) nanoparticles with good photocatalytic properties, and add them to the composite resin to improve the mechanical properties and photocatalytic antibacterial capability of the resin. The microstructure and chemical composition of Ag-TiO2 nanoparticles and composite resins were characterized. The results indicated that Ag existed in both metallic and silver oxide state in the Ag-TiO2, and Ag-TiO2 nanoparticles were uniformly dispersed in the resins. The results of mechanical experiments suggested that the mechanical properties of the composite resin were significantly improved due to the incorporation of Ag-TiO2 nanoparticles. The antibacterial results indicated that the Ag-TiO2 nanoparticle-filled composite resins exhibited excellent antibacterial activities under 660 nm light irradiation for 10 min due to the photocatalysis, and the Ag-TiO2 nanoparticle-filled composite resins could also exhibit excellent antibacterial activities after contact with bacteria for 24 h without light irradiation because of the release of Ag ions. In summary, this study provides a new antibacterial idea for the field of dental composite resins.