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.
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.
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.
It is in urgent need clinically to look for an ideal substance for the coverage of burn wounds owing to shortage of autografts or allografts. After the cadaveric skin was extracted with acetic acid, salted out with NaCl and freeze-dried to prepare a porous collagen membrane. The membrane was seeded with allo-epidermal cells and allo-fibroblasts on its two sides, respectively, and then was cultured to achieve an artificial composite allograft. The artificial composite allograft was then transplanted onto ten severly burned wounds. One-year follow-up showed satisfactory results and the histological examination confirmed that the composite allograft could improve the adherence and growth of the epidermal cells and was helpful for blood vessels and healing of non-inflammatory connective tissues in the wounds.
Objective To review the current status and problems in the developing scaffolds for the myocardial tissue engineering appl ication. Methods The l iterature concerning the myocardial tissue engineering scaffold in recent years was reviewed extensively and summarized. Results As one of three elements for tissue engineering, a proper scafold is veryimportant for the prol iferation and differentiation of the seeding cells. The naturally derived and synthetic extracellular matrix (ECM) materials aim to closely resemble the in vivo microenvironment by acting as an active component of the developing tissue construct in myocardial tissue engineering. With the advent and continuous refinement of cell removal techniques, a new class of native ECM has emerged with some striking advantages. Conclusion Through using the principle of composite scaffold, computers and other high-technology nano-polymer technology, surface modification of traditional biological materials in myocardial tissue engineering are expected to provide ideal myocardial scaffolds.
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.
ObjectiveTo investigate the effect of repairing radial bone defect with scaffold material of attapulgite/collagen type I/poly (caprolactone) (ATP/Col I/PCL) in rabbits and the possibility as bone graft substitutes.
MethodsATP/Col I/PCL materials were prepared via adding ATP to hexafluoroisopropanol after dissolved Col I/PCL (3∶2), and Col I/PCL materials via dissolving Col I/PCL (3∶2) in hexafluoroisopropanol served as control. The structure of scaffolds was observed under scanning electron microscope (SEM). Twenty-four Japanese white rabbits (male, 2 months old) were used to establish the bilateral radius defect model of 15 mm in length, and randomly divided into group A (6 rabbits, 12 defects), group B (9 rabbits, 18 defects), and group C (9 rabbits, 18 defects); then the Col I/PCL scaffold was implanted in the bone defect area in group B, the ATP/Col I/PCL scaffold in group C, no treatment was done in group A as control. The general condition of rabbits was observed after operation, and bone defect repair was evaluated by X-ray at 4, 8, and 12 weeks. At 12 weeks, the tissue of defect area was harvested for the general, SEM, Micro-CT, histological, and immunohistochemical staining to observe defect repair and material degradation.
ResultsSEM observation showed that two kinds of materials were porous structure, ATP/Col I/PCL structure was more dense than Col I/PCL. All animals survived to the end of experiment, and no incision infection occurred during repair process.X-ray films showed that the bone marrow cavity was re-opened in defect area of group C with time, the repair effect was superior to that of groups A and B. At 12 weeks after operation, general observation showed that scaffold material had good fusion with the surrounding tissue in groups B and C, defect was filled with connective tissue in group A. SEM indicated that the surface and pore of the scaffold were covered with a large number of cells and tissues in groups B and C. Micro-CT demonstrated that the new bone volume, bone mineral content, tissue mineral content, and connectivity density of group C were significantly higher than those of groups A and B (P<0.05). The observation of histology and immunohistochemical staining indicated that there were lots of connective tissues in defect area of group A, and ALP, Col I, and OPN were weakly expressed; there were many collagen fibers in scaffold degradation area in group B, and the expression levels of ALP, Col I, and OPN were higher than those of group A; there was few new bone in group C, the degradation rate of the scaffold was slower than that of group B, and the expression of Col I and OPN were enhanced, while ALP was weakened when compared with groups A and B.
ConclusionATP/Col I/PCL composite scaffold material can degrade in vivo, and has dense three-dimensional porous structure, good biocompatibility, and high potentiality of bone repair, so it can be used as bone substitute material.
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.
ObjectiveTo observe the ability of osteogenesis in vivo using the injected absorbable polyamine acid/calcium sulfate (PAA/CS) composites and assess their ability to repair bone defects.
MethodWe selected 48 New Zealand white rabbits, and half of them were male with a weight between 2.0 and 2.5 kg. Bone defect models were made at the rabbit femoral condyle using electric drill, and the rabbits were divided into two groups. One group accepted implantation of the material at the defect, while nothing was done for the control group. After four, eight, twelve and sixteen weeks, the animals were killed. The line X-ray and hard tissue slices histological examination (HE, MASSON staining) were observed to assess the situation of degradation, absorption and bone formation of the material.
ResultsFour weeks after operation, bone defect of the experimental group had no obvious callus growth on X-ray imaging. Histology showed that the material began to degrade and new immature trabecular bone grew. The bone defect of the experimental group had a small amount of callus growth on X-ray imaging after eight weeks. And histology showed that the material continued to degrade and new immature trabecular bone grew continually. There was an obvious callus growth after twelve weeks, and the bone defect area had smaller residual low-density shadow on X-ray imaging. Histology showed that most of the materials degraded and parts of woven bone grew into lamellar bone. After sixteen weeks, the composites were absorbed completely, replaced by new bone tissues, and the new bone was gradually changed from woven bone into mature plate of bone. There was no significant change in bone defect in the control group within twelve weeks, and part of bone defect hole became smaller, and partial edge repair could be detected.
ConclusionsThe PAA/CS composites can be completely degraded and absorbed, with a certain activity of bone formation, expected to be used as bone repair materials.
OBJECTIVE To study the effect of combined application of external cyclosporine A (CsA) and CTLA4Ig in inhibiting rejection and inducing immune tolerance in composite tissue allograft. METHODS: The auricles with vessel pedicle were transplanted from Lewis rats to BN rats under microsurgery. CsA was spreaded on the surface of grafts in combination with administration of CTLA4Ig intraperitoneally after transplantation. The rejection response and survival time of grafts were observed, and the IL-2 level in serum was measured. RESULTS: The mean survival time was (7.8 +/- 1.7) days in control group. It was (15.2 +/- 1.9) days when recipients treated by CsA and (16.6 +/- 2.1) days by CTLA4Ig. Under the combination of CsA and CTLA4Ig, the mean survival time was significantly prolonged to (28.8 +/- 3.5) days (P lt; 0.05) with the lowest level of IL-2 in serum of recipients. CONCLUSION: The combined application of external CsA and CTLA4Ig inhibits rejection of allograft effectively, which can be a favorable therapy on composite tissue allo-transplantation.
