A mechanical study on the bones of 29 rabbits following implantation of carbontendon was carried out. The rabbits were divided into seven groups according to the observation time (2,4,6,8,12,20 and 30 weeks after operation). A bundle of artificial tendon composed of 7,000 carbon fibers was passedthrough a tunnel in the tibia, and both ends of the artificial tendon were ligated to the muscle fibers. The mechanical strength and histological structure of the carbonbone junction and their relationship were studied in each group. Carbon fiberwas split and degradated in six to eight weeks after operation. The tensile strength of carbontendon in the soft tissue was decreased from 82±4.6N in the second week to 27±5.31N and6.3±1.81N in the sixth and eighth week respectively. The tensile strength of carbontendon increased from 3.01±1.2N to 6.1±2.01N at the carbon -tendon-bone junction in the bone. The tensile strength of carbon-tendon was unsatisfactory for implantation into bone. The carbon-tendon was split and degradated and the tensile strength was not b enough to cope with the early functional exercises.
Objective To investigate the possibility of repairing defected tendon with a tissue engineering tendon, combined culture of allogenous tenocyte and derived tendon. Methods Macaca tenocytes labelled by BrdU were seeded on the derived tendon. The flexor digitorum profundus of five fingers of left hand in 15 Macaca mulatta were resected and made 2.5cm defects as experimental model. They were divided into three groups according to repair methods (Group A: Combined culture of derived tendon materials and alloggenous tendon cells; Group B; Derived tendon materials; Group C; Autograft). In different stages, the labeled BrdU of tendon cells were observed. Results In Groupo A, after iin vivo implantation, the tenocytes could proliferate and synthesize collagen; the new tissue was white and glossy and the collagen fibers fused to form dense tendon structure as several weeks passed. Twelve weeks after implantation, the tenocytes still survived and synthesized collagen, the results of labelled cells were positive by immunothistochemical methods. By scanning electron microscopic observation, the tenocytes arraged regularly and evely among the derived tendon; the collagen fibers formed a network and its main direction was accord with that of the derived tendon. Normal nucleus, nucleolus, and cell organelles were seen under transmission electron microscope. Conclusion Combined culture of tenocytes with derived tendon is able to make tendon like tissue. The structure of tissue engineering tendon in similar to that of normal tendon.
Objective To observe the expression of related proteins of retina after subretinal implantation with inactive chips.Methods A total of 27 healthy adult New Zealand white rabbits were randomly divided into three groups: operation group (12 rabbits) in which the rabbits were implanted with inactive chips into the interspace beneath retina;shamoperation group (12 rabbits) in which the rabbits were implanted with inactive chips into the interspace beneath retina which was taken out immediately;the control group (3 rabbits). Animals were sacrified for immunohistological study 7,15,30 and 60 days after surgery.The rabbits in control group group were sacrified for immunohistological study after bred for 30 days.The expressions of glial fibrillary acidic protein (GFAP) and brain derived neurotrophic facor (BDNF) were observed.Results In operation group, the outer nulear layer of retina thinned, and the cells in the inner nulear layer was disorganized 7,15,and 30 days after the surgery;glial cells proliferated 60 days after surgery; the positive expression of BDNF and GFAP was more than that in the shamoperation and control group.In shamoperation group, the positive expression of BDNF and GFAP was more than that in the control group.No obvious difference of expression of BDNF and GFAP between each time point groups was found.Conclusions The expression of neroprotective related proteins increased after subretinal implantation with inactive chips suggests that limited neuroprotective effects might be led by the implantation.
OBJECTIVE: To evaluate the clinical effect of drilling procedure following the hydroxyapatite orbital implantation. METHODS: From February 1996 to April 2000, 146 consecutive patients who received hydroxyapatite orbital implant were drilled and inserted a motility peg 6 to 16 months after hydroxyapatite implantation. Among them, there were 97 males and 49 females, aged from 18 to 60 years old, of the 146 motility pegs, 36 were sleeved pegs and 110 were nonsleeved. Goldman visual field analyzer was applied to measure the degree of artificial eye’s movement before and after drilling. RESULTS: Followed up for 1 to 40 months, no secondary infection occurred. The mobility of the prosthesis increased from (18.7 +/- 3.8) degrees preoperatively to (42.3 +/- 3.7) degrees postoperatively. CONCLUSION: The delayed drilling procedure and motility peg insertion improve the range of movement and the sensitivity of the artificial eye with a low rate of complications.
ObjectiveTo explore the antitumor effect of tumor vaccine fused from dendritic cells (DC) and Walker-256 cancer cells on implanted liver cancer in rats and the related mechanism of inhibition for tumor angiogenesis. MethodsWalker-256 cancer cells and mature DC were fused by 50% polyethylene glycol method for preparation of DC-Walker-256 fusion vaccines. Implanted liver cancer models were established through operations on healthy male SD rats at the age of 6－8 weeks. All the rats were divided into four groups, and rats in each group were injected subcutanely with fusion vaccine (group), mixed cultured cells (group), simple DC (group), and PBS (blank control group), respectively. On 28 d after making model, the rats were put to death, the tumor was observed and pathological essays were prepared. All rats’ spleens were collected and prepared into lymphocyte to detect antigenic specificity cytotoxic T lymphocyte (CTL) by enzymelinked immunosorbent spot (ELISPOT) method. The expressions of VEGF, ANG-1, ANG-2, and MVD were detected by immunohistochemistry. ResultsThe numbers of rats survived in the fusion vaccine group, mixed culture cells group, simple DC group, and blank control group was 8, 5, 6, and 3, respectively. The rats in the other three groups except for fusion vaccine group were manifested as inaction, anorexia, and gloomy fur in some degree as well as ascites. The tumorigenesis was found in all survival rats except for two in the fusion vaccine group. The weight of liver tumors of rats in the fusion vaccine group 〔(32.4±9.2) g〕 was significantly lighter than that in the mixed culture cells group 〔(67.3±5.1) g, P=0.031〕, simple DC group 〔(75.0±8.3) g, P=0.019〕, and blank control group 〔(86.6±10.5) g, P=0.008〕, respectively. The number of tumorspecific CTL of rats in the fusion vaccine group was also significantly higher than that in the other three groups (P=0.019, P=0.025, and P=0.001, respectively). The MVD of tumor tissue in the fusion vaccine group was (24.12±2.32) vessels/HP, which was significantly lower than that in the mixed culture cells group 〔(40.34±1.29) vessels/HP, P=0.025〕, simple DC group 〔(42.36±3.16) vessels/HP, P=0.035〕, and blank control group 〔(56.48±5.16) vessels/HP, P=0.006〕, respectively. The MVD of tumor tissue in the mixed cultured cells group and simple DC group was similar (P=0.165), however, which was significantly lower than that in the blank control group (P=0.040 and P=0.043). The positive rate of VEGFA protein expression was 23.2% in the fusion vaccine group, which was significantly lower than that in the mixed culture cells group (42.5%, P=0.031), simple DC group (61.3%, P=0.019), and blank control group (89.6%, P=0.003), respectively. The positive rate of VEGF-A protein expression in the mixed cultured cells and simple DC groups was similar (P=0.089), however, which was significantly lower than that in the blank control group (P=0.027 and P=0.038). The positive rate of ANG-1 protein expression in the fusion vaccine group (43.2%) was not different from that in the mixed culture cells group (46.3%, P=0.292), simple DC group (51.3%, P=0.183), or blank control group (49.6%, P=0.179), respectively, and the difference of pairwise comparison in latter three groups was not significant (P=0.242, P=0.347, and P=0.182). The positive rate of ANG2 protein expression was 19.2% in the fusion vaccine group, which was significantly lower than that in the mixed culture cells group (62.3%, P=0.007), simple DC group (67.3%, P=0.005), and blank control group (71.6%, P=0.004), respectively, however, the difference of pairwise comparison in latter three groups was not significant (P=0.634, P=0.483, and P=0.379). ConclusionFused vaccine can induce CD8+ CTL aiming at tumor cells and establish the effective antitumor immunity in vivo and also downregulate the level of VEGF and ANG-2 to suppress tumor angiogenesis and thereby achieve the purpose of curing tumor.
Objective To introduce a new type of bileaflet mechanical prosthetic heart valve （GK bileaflet valve）and evaluate clinically the early hemodynamic effect and short term follow-up after its replacement. Methods Sixty-one patients with heart valve diseases were operated upon. The mitral valve replacement was performed in 34 patients, aortic valve replacement in 16 patients and double valve replacement in 11 patients. A total of 72 GK bileaflet mechanical valves were implanted, 45 in mitral position, and 27 in aortic position. Blood consistency and hemodynamics were monitored. Follow-up was carried out routinely to check whether there were some valve-related complications. Results There was no early mortality （〈30 d）. Only one patient died of trauma 2 months after the operation. Follow-up was 100% and extended 1 to 2. 5 years. Without valve-related complications all patients had lived for more than 1 to 2.5 years. In 98% （60/61） of survivors heart functional performance had improved to New York Heart Association class Ⅰ or Ⅱ . Conclusion Early clinical results and short term follow up demonstrate that GK bileaflet prosthetic heart valve exhibits excellent hemodynamic properties, satisfied blood consistency and a low incidence of valve-related complications. Midterm and long-term results should be observed further.
Objective To investigate whether the implanted myoblasts with the soluble carriers can improve the repairing efficiency for theseverelycryodamaged tibialis anterior muscles. Methods The skeletal myoblasts were isolated from the newborn SD rats by the use of the enzyme digestion. They were purified and serially subcultivated; the subcultivated myoblasts of the 3rd generation were marked with BrdU. The severelycryodamaged tibialis anterior muscle models were established from 84 SD rats aged 5 months. They were randomly divided into 4 groups, including Group A1 (the implanted myoblasts with the carriersF12 containing 0.1% sodium hyaluronate), Group A2 (the implanted myoblasts, with the carriersF12 that did not contain 0.1% sodiumhyaluronate), Group B1 (the implanted carrier solution containing 0.1% sodium hyaluronate, but with no myoblasts), and Group B2 (with no carrier solution or myoblasts). Six rats were killed at the following time points: at 2, 5 and 9 days,and 2, 4, 8 and 12 weeks after operation; the immunohistochemical and the Mallory staining studies were performed for an evaluation on the repairing efficiencyfor the severelycryodamaged tibialis anterior muscles. By the imaging analysis, the number of the survived cells in each group was compared at 2 days, and the area ratio of the collagen fiber in each group was also compared at 8 weeks. Results The BrdU immunohistochemical staining showed that the number of the remaining implanted cells was significantly greater in Groups A1 than in Group A2, the migrating area of the myoblasts was greater, the distribution of the cells was more uniform, the cell differentiating potential was undestroyed, the repairing efficiency for the severelycryodamaged tibialis anterior muscles was significantly improved. There was no bluestained nucleus at each time point in Group B. The Mallory staining showed that the fibrous degeneration inthe tissue repairing process was significantly inhibited in Groups A1, A2 and B1; the inhibition was most obvious in Group A1, and next in Group A2. The imaging analysis indicated that at 2 days after operation, the number of the survived cells was significantly-greater in Group A1 than in Group A2 (Plt;0.05). At 8 weeks after operation, the collagen fiber was the least in Group A1, less in Group A2, more in Group B1,and the most in Group B2 (Plt;0.05). Conclusion The implanted myoblasts can significantly improve the repairing efficiency for the severelycryodamaged muscle tissues, and the implanted carrier solution containing 0.1% sodium hyaluronate can improve the implanting efficiency for the myoblasts.
OBJECTIVE: To investigate the method and clinical effect of temporal fascia flap, free forearm flap, free iliac bone transfer and immediate implant on reconstruction of maxillary defect. METHODS: From February 1999 to July 2002, 8 cases of maxillary defects due to excision of cancer were repaired immediately with temporal fascia flap, free forearm flap, free iliac bone transfer and implant. Out of 8 patients, there were 6 males and 2 females, aged 32-49 years, with a disease course of 3 months to 2 years. RESULTS: Free iliac bone and forearm flap survived in all 8 cases. Osseo-integration could be seen and the implants could be used for denture repair and chew function. After 6-12 months, X-ray examination showed iliac bone healing; facial shape and functional restoration were satisfactory. CONCLUSION: Temporal fascia flap, free forearm flap, free iliac bone transfer and immediate implant is an ideal method to repair maxillary defect immediately and reconstruct its function.
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.
Objective To explore the effective autologous bone marrow stem cell dosage for treatment of severe lower limb ischemia. Methods From December 2003 to December 2004, 22 cases of bilateral lower limb ischemia were treated with autologous bone morrow cell transplantation. All the patients were randomly divided into two groups according to ischemia degree. In group A(severe ischemia side), the amount of transplanted autologous bone marrow cells was more than 1×108, and ingroup B(mild ischemia side), the amount was less than 1×105. A series of subjective indexes, such as improvement of pain, cold sensation and numbness, and objective indexes, such as increase of ankle/brachial index (ABI) and transcutaneous oxygen pressure (TcPO2), angiography, amputation rate, and improvement of foot wound healing were used to evaluate the effect of autologous bone marrow stem cells implantation. Results The rates of pain relief were 90.0% in group A and 16.7% in group B (Plt;0.01); the rates of cold sensation relief were 90.5% in group A and 5.3% in group B（Plt;0.01）;the improvement of numbness was 62.5% in group A and 9.1% in group B（Plt;0.01）. Increase of ABI was 31.8% and 0 in groups A and B respectively（Plt;0.01） at 4 weeks after implantation. Increase of TcPO2was 94.4% and 11.1% in groups A and B respectively（Plt;0.01） at 4 weeks after implantation. Twelve cases of angiography showed rich new collateral vessels in 100% of the limbs in group A while no remarkable new collateral vessel in group B. The amputation rates were 4.5% in group A and 27.3% in group B（Plt;0.05） at 4 weeks after implantation. The rate of improvement of foot wound healing was 75% in group A and there was no changein wound healing in group B after 4 weeks of implantation. Conclusion The effectiveness of autologous bone marrow stem cell implantation depends on the number of implanted stem cells. Effectiveness is expected in most patients if the implanted stem cell is more than 1×108, whereas there would be little effect if the cell number is less than 1×105.
