Analysis of relationship between single umbilical artery diagnosed by prenatal ultrasonography and fetal malformation / 中华超声影像学杂志

To evaluate the value of prenatal ultrasound in the diagnosis of single umbilical artery( SUA ) and fetal malformation . Methods T he characteristics of the prenatal ultrasound findings of 143 fetuses with SU A in different gestational weeks were retrospectively analyzed ,and the missing side of SU A were checked . Different types of SUA combined with fetal malformation were analyzed as well as chromosomal abnormalities and so on . Results For 143 fetuses with SU A ,there were 83 cases ( 58 .0% ) with absent left umbilical artery and 60 cases ( 42 .0% ) with absent right umbilical artery ,there was no statistical difference between the two groups ( P ＞0 .05 ) . Six cases ( 4 .2% ,6/143 ) were detected at and before 20 weeks of gestation ,and the rest 137 cases were detected after 20 weeks( 95 .8% ,137/143) . T here were 121 cases ( 84 .6% ) of isolated SUA ,22 cases ( 15 .4% ) were complicated with other malformations , including 10 cases ( 45 .5% ) with absent left umbilical artery and 12 cases ( 54 .5% ) with absent right umbilical artery . T here was no statistical difference between left and right umbilical artery deletion combined with fetal malformation( χ2 ＝1 .692 ,ν＝1 , P ＞0 .05) . T here were 11 cases( 7 .7% ,11/143) with cardiovascular malformation and nine cases ( 6 .3% , 9/143 ) with digestive system malformation . Chromosome examination was performed in 23 cases . One case of trisomy 18‐trisomy and 1 case of trisomy 13‐trisomy were found to be with missing right umbilical artery and all of them were complicated with multiple deformities . Conclusions The absence of left and right umbilical artery can be combined with abnormal fetal malformation . Prenatal ultrasonography can accurately diagnose SU A and fetal malformation .

Observation on vascularization of big segmental bone defect repaired by heterogeneous deproteinized bone / 中国矫形外科杂志

0.05).[Conclusion]Composite of heterogeneous deproteinized bone+autogeneous MSCs+rhBMP2 has the same ability of autogeneous bone graft to repair big experimental segmental tibia defect,thus it can be used as a scaffold in tissue engineering and for further study of immunogenicity and ossification ability.

Changing regularity of articular function in the slow lengthening process of limbs / 中国组织工程研究

BACKGROUND: As reported in some literatures, articular dysfunction following limb lengthening is one of the commonest complications, but some scholars believe that the articular dysfunction after lower limb lengthening is avoidable providing appropriate technical operation and effective function prevention.OBJECTIVE: To investigate the changes of articular function of knee during limb lengthening in rabbits so as to provide a experimental basis for clinical tasks.DESIGN: A randomized controlled trial SETTING: Department of Orthopeadics, Affiliated Hospital of Some Military Medical University.PARTICIPANTS: Study was conducted in the Experimental Animal Center of the Third Military Medical University of Chinese PLA from February 2001 to June 2002. Totally 30 healthy adult New Zealand rabbits obtained from the Experimental Animal Center of the Third Military Medical University of Chinese PLA were randomly divided into lengthening group and delayed observation group(observed at 3 months after the stop of lengthening).METHODS: Every group was further divided into three sub-groups according to distraction range: 10%, 20% and 40%. Upper-tibia metaphysis distraction was adopted at the rate of 1 mm per day . Distraction and iconography changes of knee joint were observed with X-ray. The motive range of knee was investigated at the end of distraction and three months later.MAIN OUTCOME MEASURES: Articular motive range of the knee before the distraction, at the end of distraction and three months later, X-ray resutls RESULTS: ① There was no obvious radiographic change in knee at every time point in each group. ② Significant flexion disorder in knee was found in 20% distraction subgroup( P ＜ 0. 05), which was only 44. 7% of normal motive range in 40% distraction subgroup( P ＜ 0. 01) . Motive functions of knee in delayed observation group were significantly improved; thereinto,20% distraction subgroup returned to preoperative level, while 40% distraction subgroup also had significant improvement compared with that of 3 months earlier but still lower than normal level, which was only about 88.5% of normal level( P ＜ 0.05).CONCLUSION: Temporary articular dysfunction might occur during limb lengthening process, and mostly during big range of distraction. Although the dysfunction could be gradually recovered after the stop of lengthening, active prevention is still necessary.

Immortalization of human articular chondrocytes and induction of their phenotype / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To immortalize human articular chondrocytes (HACs) using gene transfection and to maintain stable phenotype of transformed HACs after induction.</p><p><b>METHODS</b>HACs were transfected with the retroviral vector pLXSN encoding human papillomavirus 16E7 (HPV16E7), and the transformed clones were sorted and proliferated. Karyotype analysis, clone forming tests and nude mice tumor forming tests were applied to check the characteristics of the transformation. Type II collagen of transformed chondrocytes was inducted with free serum medium (FSM) supplemented with nutridoma-sp and ascorbate.</p><p><b>RESULTS</b>Immortalized HACs were isolated with fifty passages achieved. The HPV16E7 transformed cells were confirmed to be benign. Induction of FSM with nutridoma-sp and ascorbate promoted type II collagen of transformed chondrocytes to the high levels of normal chondrocytes.</p><p><b>CONCLUSION</b>HACs transformed with HPV16E7 survive for long periods in vitro, and type II collagen can maintain stability after induction.</p>

Biomechanical test of suture fixation strength at ligament-tendon free end which used in cruciate ligament reconstruction / 中国组织工程研究

Aim To test the strength of Kraekow bilateral locking stitchfor tendon or ligament free end fixation and evaluate the stitch which wasused in reconstruction of cruciate ligament or secure fixation of soft tissue tobone. Methods Twenty-four specimens of patellar tendon free end, whichwere divided into 3 groups according 2 or 3 stitches and 6 subgroups ac-cording No1 Ethilon or 0.4 mm diameter stainless steel wire different suturematerials, fixed with Krackow locking stitch, were undertaken the tensiletest respectively, so as to find out the least stitches and efficient suture pat-tern. Results 2 Krackow locking stitches had more strength than that of0.4 mm diameter stainless steel wire, the fixation strength of 2 stitcheswhich used No1 Ethilon was more than 80 N, superior to the failure strengthof material itself, it still maintained the same strength if the first stitch wasacross the tendon tissuetransversely. There was no significant differencebetween 2 and 3 Krackow locking stitches in suture strength statistically, thefixation strength was superior to the suture material, it could reduce the'suture exposure when the first stitch is across the tendon tissue while main-tains a comparable strength to other suture. Conclusion If attempt to makea higher strength of suture, we should focus on selecting a stronger materialsor adding the suture materials in number rather than the stitch number.

Inhibition effects of basic fibroblast growth factor on c-fos gene expression after tractive spinal cord injury in rats / 第三军医大学学报

Objective To observe the effects of basic fibroblast growth factor on c-fos gene expression in spinal cord neurons of rats after tractive spinal cord injury. Methods The animal model of SD rats with tractive spinal cord injury was established through tracting T_ 13-L_2 spine longitudinally with a special spinal tractor that was put on parapophysis of T_ 12-L_3 vertebrae after exposing T_ 13-L_2 spinal cord via dual laminectomy, meanwhile spinal cord function was monitored by cortical somatosensory evoked potential (CSEP). Forty model rats were randomly divided into 2 groups, the bFGF treatment group (n=20) with bFGF injection into the subarachnoid cavity and the control group (n=20) with saline injection. Five SD rats without any treatment served as normal control. The c-fos gene expression was detected with immunohistochemistry and analyzed quantitatively with image system of computer. Results The c-fos gene expression in tractive spinal cord injury was higher than that in normal control group, especially increased markedly in damaged neurons. The peak value of c-fos gene appeared in 2 h after the injury, but c-fos level in the bFGF treatment group was lower evidently than that in the control group at the different sacrificed time (P

Isolation of chondrocytes from rabbit rib cartilage with three-step enzymatic digestion and their biological characteristic in vitro / 第三军医大学学报

Objective To observe the effect of isolating and harvesting the chondrocytes from rabbits rib cartilage with the method of three-step enzymatic digestion, and the biological characteristic of the isolated chondrocytes during cultivation in vitro to evaluate their biological activity. Methods The method of three-step enzymatic digestion was designed that the rib cartilage was digested one by one with 1 g/L trypsin and 1 g/L EDTA, 1 g/L hyaluronidase and 2 g/L collagenaseⅠ in the culture medium to isolate chondrocytes. The harvesting and viability rate of the primary chondrocytes were detected. During the passage cultivation in vitro, the changes of the chondrocyte shape and growth were observed, and the changes of the collagen typeⅠ and Ⅱ and aggrecan in the extracellular matrix were detected. Results ① The extracellular matrix of rib cartilage was completely dissolved by the three-step enzymatic digestion, and the chondrocytes were completely isolated from the solid matrix. The number of the harvested chondrocytes from every gram of wet cartilage was (4 295.7)?10~(4) on average,and their viability rate was 97.2% on average. ②The primary and first passage chondrocytes had triangle or multi-angle shape, and became elliptic shape at the growing confluence with the positive immunohistochemical staining of collagen type Ⅱ and the strong heterochromia to toluidine blue. The content of sulfate glycosaminoglycans(GAG) in the extracellular matrix of the primary passage cells was (80.61?11.40) ?g/cm~(2). The chondrocytes after the third passage gradually became spindle shape with the negative staining of collagen typeⅡ and the weak heterochromia to toluidine blue. The content of sulfate GAG of the fourth passage cells was (44.74?10.18) ?g/cm~(2). Conclusion ① The method of three-step enzymatic digestion can make the extracellular matix of rib cartilage to be completely degraded, and has advantages of the high efficiency of harvesting primary chondrocytes with high cellular viability rate and simple manipulation. ②The primary and first passage chondrocytes have fine biological activity.

Measurement of rabbit marrow mesenchymal stem cells isolated and observation on their biological characteristic in vitro / 第三军医大学学报

Objective To establish the measurement for evaluating the efficiency of isolating and harvesting marrow mesenchymal stem cells (MSCs) and observe the main biological characteristic of MSCs in vitro during the passage cultivation. Methods ①The marrow nucleated cells in young rabbit marrow were isolated by the gradient centrifugation and cultivated to isolate and harvest MSCs. The efficiency of isolating and harvesting MSCs was measured by the number of the first passage MSCs from every 10~(6) of the marrow nucleated cells. ②The changes of MSCs morphology, growth and proliferation, synthesis of collagen typeⅠand activity of alkaline phosphatase (ALP) were observed during the passage cultivation. Results ① After cultivated at 2.5?10~(5)/cm~(2) marrow nucleated cells for 9-10 d, the first passage MSCs were harvested. The number of the first passage MSCs had a remarkable statistical positive correlation with the number of the marrow nucleated cells from one rabbit(r=0.932, P

Effect of basic fibroblast growth factor on ChAT expression in tractive spinal cord injury in rats / 第三军医大学学报

Objective To observe the effect of basic fibroblast growth factor on ChAT expression in neurons after tractive spinal cord injury in rats.Methods The animal model of tractive spinal cord injury in 36 SD rats was established.The bFGF-treated rats(n=18) received 20 ?l bFGF solution containing 20 ?g bFGF into subarachnoid cavity immediately,or at 1,2,3,4,8,12 and 24 h after animal model establishment,while the saline-treated rats(n=18) received the equal volume of normal saline at the same time.Another 6 normal SD rats underwent no treatment as normal controls.All rats were killed on postoperative day 4,7,14.The choline acetyltransferase(ChAT) were detected by immunohistochemistry preoperatively and on day 4,7,14 after spinal cord injury.Results The number of neurons positive of ChAT decreased gradually after tractive spinal cord injury.After bFGF treatment,positive neurons of ChAT increased in number,with significant difference between the bFGF-treated group and saline-treated group(P

Clinical results of shoulder arthroplasty with the UNIVERS 3-D prosthesis in rheumatoid arthritis / 第三军医大学学报

Objective To evaluate the clinical results of arthroplasty with the UNIVERS 3 D prosthesis in shoulder rheumatoid arthritis (RA). Methods Six cases of shoulder RA underwent the arthroplasty with the UNIVERS 3 D prosthesis. Five cases were strictly reviewed by Constant score and normalized Constant score after operation with an average follow up of 26 months, ranging from 12 to 45 months. Five cases were reviewed by the radiological analysis on preoperative and postoperative X ray including three AP views, scapular view, and axillary view. The radiographic forms were classified by two different criteria according to Levigne. Results The postoperative Constant score (mean, 55.06) and normalized Constant score (mean, 72.2%) were improved more than one time in all cases except one. Complication of anterior superior subluxation occurred in glenohumeral joint of one case and no surgical treatment performed. The radiographic forms were classified by Levigne on humeral head wear (including 2 cases of microgeodes, 1 case for notch in the greater tuberosity, and 3 cases for spherical form loss) and on the sphericity and upward migration of the humeral head (1 case for ascending form, 1 case for centered form, and 4 cases for destructive form) according to the clinical results. Conclusion The arthroplasty with the UNIVERS 3 D prosthesis results with excellent clinical function results in shoulder RA without any radiolucent line and with very low complication. Radiological classification on the sphericity and upward migration of the humeral head, and humeral head wear may be useful element in operation choice and its prognosis.

Effects of limb lengthening on metabolism of articular cartilage in experimental rabbits / 第三军医大学学报

Objective To investigate the adaptation of metabolism of the arthrodial cartilage for limb lengthening. Methods Thirty New Zealand rabbits were divided into two groups: limb lengthening group (A) and delayed observation group (B). Each group was further divided into three sub groups ( n =10) according to the distraction ranges: 10%, 20%, and 40%. Upper tibia metaphysis lengthening was adopted at 1 mm/d rate of distraction and iconography changes of the knee joint were observed with X ray. The contents of glycosaminoglycan (GAG), hydroxylysine (HYL), and hydroxyproline (HYP) were determined by biochemical techniques. Results ① There was no obvious imaging change of knee articular cartilage at every time point in each group. ② The content of GAG was normal in group A 10 , and B 10 , and B 20 , but the content of galactosamine decreased obviously in group A 20 ( P 0.05). The content of GAG recovered obviously in group B 40 as compared with that in group A 40 . ③ The ratio of HYL to HYP was 0.18 and 0.17, respectively in group A 40 and group B 40 , but it was normal in other groups, nearly 0.24. Conclusion Metabolism of the arthrodial cartilage during low distraction range can adapt the stimulation of distraction, but great distraction range may result in transitory disorder in metabolic function of the arthrodial cartilage.

Effects of point contact-dynamic compression plate on cortical bone blood flow in adult goats / 中华创伤杂志

Objective To compare the effects of point contact-dynamic compression plates (PC-DCP) and dynamic compression plates (DCP) on cortical bone blood flow in an intact sheep tibia model. Methods Fifteen mature goats were used in this experiment. After the bilateral tibia of goats were fixed with DCP and PC-DCP respectively, the regional cortical bone blood flow was measured at four time intervals (1 day, 2, 6 and 12 weeks after operation) using radiolabelled microsphere technique. Results After operation, the cortical bone blood flow was acutely decreased at the first day, kept lower than normal level until six weeks and recovered at the 12th week. The blood supply under PC-DCP recovered to normal, even over normal level two weeks after operation and remained at a high level until 12 weeks. Conclusions PC-DCP can markedly protect cortical bone blood flow.

Clinical results of shoulder arthroplasty with the UNIVERS 3-D prosthesis in treatment of post-traumatic gleno-humeral arthritis / 中华创伤杂志

Objective To evaluate clinical results of arthroplasty with the UNIVERS 3-D shoulder prosthesis in post-traumatic gleno-humeral arthritis. Methods A total of 54 cases (age range of 31-84 years, mean 67.07 years) with post-traumatic gleno-humeral arthritis were treated by the arthroplasty with the UNIVERS 3-D prosthesis. Constant score and normalised Constant score were used to strictly evaluate the preoperative function of 45 cases, of which 30 cases were reviewed by Constant score and normalised Constant score postoperatively with an average follow-up of 12-68 months. Of all, 44 cases were strictly followed up in respect of preoperative and postoperative X-ray including anteroposterior, axial and Y-shaped positions. Results Compared with the pre-operation, there was a significant increase in post-operative pain, activity, mobility and strength as well as the postoperative Constant score and normalized Constant score. Total shoulder arthroplasty (TSA) provided better score for daily life and mobility than hemiarthroplasty, with a significant difference (P

Treatment of complex bone nonunion with external skeletal fixation / 中华外科杂志

<p><b>OBJECTIVES</b>To summarize the experience in the treatment of 112 cases of complex bone nonunion from 1982 to 1999 in our department and introduce the technique of external skeletal fixation.</p><p><b>METHODS</b>The two fragment ends of all cases were fixed under pressure with half-ring sulcated external skeletal fixator. Those cases complicated by bone defect or limb shortening were operated on with epiphysiotomy to restore the length of the limb in the period of compressive fixation or after the occurrence of bone union according to the condition of complicated infection and the length of the limb shortened.</p><p><b>RESULTS</b>The nonunion of the 112 cases was united eventually. The infection in 34 cases was eradicated. Bone union in cases without infection took 3 approximately 7 months (average 5.2 months) and in cases with infection took 5 approximately 11 months (average 5.5 months). The length of the limb in 11 cases with bone defect was restored in the same period of compressive external fixation and another 8 cases achieved after bone union. The length between the injured and healthy limbs was balanced.</p><p><b>CONCLUSIONS</b>When external skeletal fixation is employed to treat those troublesome cases of bone nonunion, the pins for fixation are inserted in sites far from the lesions and the non-united fragment ends are exposed only in the area without scars. Consequently, there is little interference with the blood circulation and the osteogenic potency of the fragment ends. The sclerotic bone tissue is not excised, the marrow cavity is not chased to be open and the fragment ends are only moderately modified. As a result, the stability of fixation is increased and further shortening of the limb avoided. External skeletal fixation using small pins with cross penetration results in plastic fixation and promotes bone healing. Bone lengthening with epiphysiotomy can restore the balance of the limbs.</p>

The experimental study of culture in vitro of fibroblasts seeded onto human amnion extracellular matrix (HA-ECM) / 中华整形外科杂志

<p><b>OBJECTIVE</b>The aim of this experiment is to find proper cell carrier for skin tissue engineering.</p><p><b>METHODS</b>Various concentration of fibroblasts were seeded onto HA-ECM and cultured in vitro. The performance of cells' growth, array, adhesion and collagen secretion on HA-ECM was observed with light microscope and transmission electron microscope.</p><p><b>RESULTS</b>The fusiform fibroblasts oriented radiantly or longitudinally and closely packed onto the HA-ECM, they attached firmly and proliferated to confluence on the stromal surface of HA-ECM.</p><p><b>CONCLUSION</b>The optimal cell concentration is 3.5 x 10(6)/ml, HA-ECM is ideal carrier for fibroblasts because of its excellent scaffold and diffusion characteristics. Futhermore, it has the bioactive molecules such as fibronectin and laminin which play an important role in fibroblasts attachment and proliferation on HA-ECM.</p>

Repair of flexor tendon defects of rabbit with tissue engineering method / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To repair rabbit tendon defects with tissue engineering method.</p><p><b>METHODS</b>The third passage of fetal skin fibroblast cells was labeled with 5-bromo-2' deoxyuridine (Brdu) and then seeded on human amnion extracellular matrix (HA-ECM). Using 1 cm-long-Achilles tendon defects as repairing models in the experimental group, tendon defects were core bridged with polydioxanone (PDS) and then capsulated with the complex of fibroblasts-HA-ECM. In the control group I, defective tendons were sutured with PDS following the former procedure and capsulated with HA-ECM (without fibroblasts). In the control group II, only PDS was applied to connect the defective tendons. Gross examination, light microscopy, scanning electronmicroscopy and biomechanical measurement of the repaired tendons were respectively performed at postoperative 1, 2, 3 month as well as immunohistochemical examination.</p><p><b>RESULTS</b>The optimal cell concentration for seeding fibroblasts was 3.5 x 10(6) cells/ml. Cells grew well and radiated or paralleled on HA-ECM. Immunohistochemistry showed that the labeled seed fibroblasts played an important role in tendonization. The results of light microscopy, electron microscopy, and biomechanical assessment suggested that the rate and quality of tendonization in the experimental group was superior to those of the control group I and II. The tensile strength in the experimental group was the greatest, the next was in the control group I, and the worst in the control group II (P<0.05).</p><p><b>CONCLUSIONS</b>HA-ECM is the excellent carrier for fibroblasts. Fibroblasts-HA-ECM complex has the capability to repair tendon defect and to tendonize with rapid rate and good performance three months after operation. Its tensile strength is 81.8% of that of normal tendon.</p>

Expression of BMP and TGF-β1 in Regenerative Gap During Tibial Lengthening by Metaphyseal Osteotomy of Rabbits / 中国矫形外科杂志

To study the expression of bone morphogetic protein(BMP) and transforming growth factor β１（TGF-β１) in regenerative gap during lengthening period. Method: The right tibia of 14 mature rabbits were lengthened using metaphyseal osteotomy. Distraction was started on the 4th day postoperatively, 1mm per day and conducted twice each day. The expression of endogenesis BMP and TGF-β１ in regeneraive gap were observed during ten weeks after distraction by histology and immunohistochemisty. Results: The result showed that bone morphogetic protein(BMP) and transfoming growth factor β１(TGF-β１) were expressed in chondrocytes, osteoblasts, and fibroblasts. The expression of BMP was at a high level in initial two weeks after distraction while the expression of TGF-β１ was increased step by step. Then both of them decreased alonged with lengthening proceeding. Two weeks after distracting stopped, the expression of BMP could not being observed. But the expression of TGF-β１ could being observed all stage after distraction stopped. Conclusion: BMP and TGF-β１ were expressed persistently in regenerative gap during bone lengthening.

EXTERNAL FIXATION TREATMENT OF OLECRANON FRACTUREION WITH PRESSURE (A 94 CASES REPORT) / 解放军医学杂志

Objective To use external fixator in the treatment of fracture of the olecranon of ulna. Methods Ninety four cases of olecranon fracture were treated with external fixators. The lateral medial displacement was first reduced, followed by the reduction of the proximal fragments. In some difficult cases with comminated fracture, a Kirschner wire was inserted to lever the fracture fragments to proper site. The fragments were held together by two hands, and they were fixed with an external fixator with addition of longitudinal pressure. Results The mean healing time of all the 94 cases was 35 days (5 6 weeks), and the function of the elbow joint were restored to normal. Conculsion The method as described above is an easy, economical and safe method, and can be used in out patientdinic

Chondrogenesis of articular chondr ocytes following in vitro biphasic s eeding into three-dimensional scaffold / 中华骨科杂志

Objective To establish the technique of biphasic seeding of articular chondrocyte s in vitro for cartilage engineering in u sing a self designed biological gel a nd the three-dimensional scaffold a nd observe the efficiency of cartilage regeneration in vitro-tissue engin eered articular cartilage from cell scaffold complex.Methods The articular chondrocytes were iso lated enzymatically from the epiphyseal cartilage of young rabbits,and were then plated i nto the tissue culture flasks and were cultivated.The first passage ar-ticular chondrocytes were collecte d and mixed fully with the self-made l iquid biological gel-matrix at appr oxi-mately 2.5?10 7 cells /ml to form cell-gel fluid.The cell-gel fluid was dropped into the p orous CPPf /PLLA(calcium polyphosphate fiber /poly -L -lactic acid)scaffold,and a cell-gel-scaffold c omplex was formed after being solidified.The complexes were cultivated for 4weeks.The changes of complexes in morphology and synthesis of collagen typeⅡandⅠand aggregates were investigated under the gross and the phase and light microscope.The GAG sulfate content in complexes was quantitatively mea sured by the modified dimethyl-methylene blue method.Results1)After feeded,the porous CPPf /PLLA s caffolds were completely filled with the liquid chondrocyte-gel and the chondrocyte-gel-scaffold comp lexes were well formed by solidification.During the cultivation,the complex es could keep its original shape and m aintain the stable homogeneous three-dimensional distribution of chondrocytes in themselves without cell falling.In the same time,the com-plexes were gradually increasing th e consistency with the elasticity an d lubrication surface.2)The chondro-genesis began in the periphery area a nd extended to the central area of the complexes with the passage of cultivation period.After the 2nd we ek,the complexes were gradually reorganized into the mature engineered cartilage with typical cartilaginous histological structure,with ric h typeⅡcollagen and the strong typical het-erochromia to toluidine blue,but wi th gradually fading negative immunological stain of collagen typeⅠ.Meantime,the scaffold was graduall y de-graded in the complexes.The average content of GAG sulfate in the enginee red cartilages at 4th week was(15.70?2.00)mg /g(wet weight ),and was over 30%of the natural articular cartila ge.Conclusion The technique of chondrocytes biphasic seeding for three-dimensional scaffold has advantages of simple manipulation,fix ing cell stably in the scaffold,main-taining the original shape of the com plexes and the stable homogeneous th ree-dimensional distribution of chondrocytes in the scaffold,and ad vancing the regeneration and matura tion of tissue-engineered articula r cartilage.[

The structure and mechanical properties of the plated bone following point contact-dynamic compression plate and dynamic compression plate fixation / 中华骨科杂志

Objective To compare the effects of point contact-dynamic compression plates (PC-DCP) and dynamic compression plates (DCP) on bone structure and mechanical properties of the plated bone in the intact goat tibia model. Methods Ten matured goats were used. The bilateral intact tibia of goats were fixed with DCP and PC-DCP respectively. The goats were sacrificed at 12 and 24 weeks after operation, and the tibiae were harvested. The structure of bone under plate was studied both by CT scan and histomorphology. The mechanical properties of the plated bone were examined by torsional test. Results At 12 weeks after internal fixation, there was obvious osteoporosis in the cortical bone underneath the plate in the DCP group compared with that of the PC-DCP group. Both of the cortical bone thickness underneath the plate and the torsion strength of the plated tibiae were significantly higher in the PC-DCP group than that in DCP group (P0.05). Conclusion The underlying bone resorption after rigid plate fixation is induced by both the disturbance of the bone blood supply and stress shielding. However, the former is the main cause in the early stage of fixation. PC-DCP is able to prevent bone resorption in the early stage of fixation.