Objective:To investigate the ability of fluoride toothpaste and fluoride varnish on enamel remineralization and acid resist-ance.Methods:Enamel specimens were prepared from bovine incisors,and were randomly divided into 4 groups(n=3)after acid-etching by 37%phosphoric acid.Specimens in group A(control)was processed daily with normal saline;those in group B and C were treated once with Duraphat varnish and Fluor Protector varnish respectively;in group D was daily processed with fluoride toothpaste. All specimens were incubated in artificial saliva for 2 weeks.Then all specimens received acid-etching again.Micro-hardness test, SEM observation and image analysis were performed before and after each step.Results:After 2 weeks of processing,no remineraliza-tion was found in group A.Varnish layers were observed on the surface of specimens in group B and C.In group D remineralization was detected on the enamel surface.After re-etching,micro-hardness decreased in group A and D.Fluoride varnish layers in group B and C showed strong resistance to acid-etching.After re-etching,area of micro-holes in group A and D increased(P<0.05 ),but that in group D was smaller than in the control(P<0.05).No micro-hole was observed in group B and group C.Conclusion:Protec-tive layer formed on the enamel surface by fluoride varnish is resistant to acid-etching and promotes enamel remineralization.Fluoride toothpaste application can promote enamel remineralization,but with less resistance to acid.

Objective To discuss clinical results of treatment of trimalleolar fractures by minimally invasive surgical osteosynthesis. Methods From January 2002 to Doctober 2005, twenty-eight cases (mean age: 38.7 years) of trimalleolar fracture were treated by minimally invasive surgical osteosynthesis. Their lateral and posterior ankle joints were exposed through the Gatellier-Chastang incision. The sequence of reduction and fixation of ankle fracture was firstly the posterior ankle, then the medial and lateral malleolus, and distal tibiofibular syndesmosis lastly. Postoperatively, all the patients were fixed externally from 3 to 4 weeks with plaster splint. Results Follow-ups of 18 months on average revealed that all the cases healed. The healing time ranging from 2.8 to 4.5 months averaged 3.2 months. According to the Baird-Jackson scoring system, the results were rated as excellent in 16 cases, good in eight cases, moderate in three cases, and poor in one case, with the good-excellent rate being 85.7% . Conclusions The anatomical reduction and firm internal fixation are key factors in treatment of trimalleolar fractures. The minimally invasive surgical osteosynthesis is a good method due to the minimal invasion, a high rate of union, and fewer complications it results in.

Objective To investigate the ability of repairing bone defect with the compound of hydroxyapatite(HA),red bone morrow (RBM), bone morphogenic protein(BMP)and fibrin sealant (FS),and the feasibility with the compounds as bone substitute material. Methods The animal models of bilateral radius bone defect were created by surgery in the New Zealand white rabbits, and were treated with the compound of HA, RBM, BMP and FS, by autograft and no implant as control.The effect were observed by gross, histopathological and X-ray examinations, and were determined by biomechanics at 2,4,8 and 12 weeks after operation. Results By gross, histopathological and X-ray examinations, the effect indicated that the bone defect were perfectly repaired with autograft and the compound of HA, RBM, BMP and FS at 12 weeks, but not with the no implant group. The effect of biomechanics had no statistically significant difference between the autograft and the compound of HA, RBM, BMP and FS. Conclusion The compound of HA, RBM, BMP and FS possesses much high bone inductive potentialities and the ability of rebuilding bone defect and can serve as an autograft substitute material.

BACKGROUND:There is lack of an objective and standardized animal model for assessing the therapeutic effect of physical and medication treatment on bone defoct, the effectiveness of operation, as well as the role of bone substitute in the repairing of bone defects.DESIGN:Verified study on the experimental model of bone nonunion in rabbitsSETTING: Department of Orthopaedics in Shenzhen people' s Hospital MATERIALS:Twenty common grade pure New Zealand rabbits of either gender were selected with body mass of (2.5±0.5)kg,aged 6 to 8 months.METHODS :This experiment was carried out at the experimental animal center of Shenzhen people's Hospital between May and August 1999. 1.5cm bone segment (including periosteum)was cut off in the middle of forearm radius in 20 common grade pure NewZealand rabbits,the broken ends were covered with bone wax, 10 weeks later, the bone nonunion status was assessed by macropathological observation, pathohistological and X-ray examination.MAIN OUTCOME MEASURES:Observations on rabbit forearm radius defects by macropathological observation, pathohistological and X-ray examination.RESULTS :Twenty rabbits(40 side radius)were enrolled in this study and weeks later, bone defect region was found filled with fibrous cicatricial tissue without osseous connection ,bone wax was not absorbed, capitulum was ossified with medullary cavity blocked,a small amount of callus formed at both broken ends of fractural bone ,length of bone defect ranged from 0.8 to blocked under optical microscope,chondrocyte and osteocyte could be observed arranging disorderly and covered with fibrous membrane,defect reosseous connection could be detected at defect region at week 10,broken end was ossified and medullary cavity was blocked ,there was small amount of callus appeared at both broken ends displaying irregular shape.CONCLUSION:Bone nonunion experimental animal was successfully established on rabbits in this study, with pathological changes meeting the need of bone nonunion and displaying typical properties,which can be used as reliable and feasible experimental animal model.

BACKGROUND: The study of isolation, purification, culture, cell labeling, inducing factors, effects of gene transfection on cytobiology, cell carrier construction, and time window for back transplantation of cell compound pertaining to marrow stromal cells (MSCs) is still in its infancy. OBJECTIVE: To search for an in vitro culture method that can be simply and effectively obtained. DESIGN, TIME AND SETTING: The present cytological in vitro experiment was performed at the Beijing Institute of Genome, Chinese Academy of Sciences between June 2006 and July 2007. MATERIALS: Eight specific pathogen-free New Zealand rabbits, aged 6 weeks, were provided by the Laboratory Animal Center, Institute of Genetics and Development, Chinese Academy of Sciences. METHODS: Under sterile condition, 1 mL rabbit bone marrow was taken and diluted with D-Hanks solution. Following centrifugation and subsequent supernatant removal, bone marrow was re-suspended using dulbecco's modified eagle's medium (DMEM) for single cell suspension. Next, single cell suspension was dropped onto the liquid surface of equal-volume lymphocyte separation medium (density: 1.077). Subsequent to centrifugation, cloudlike mononuclear cell layer was collected and re-suspended with DMEM containing 20% fetal bovine serum. The cells were inoculated at lxl0/cm2 and purified by adherent method. When 70%-80% of flask bottom was covered, cell digestion and passage was performed.MAIN OUTCOME MEASURES: Cell growth was observed with an operating microscope. Surviving cells were counted by Trypan blue viability test. Cell identification was performed by hematoxylin-eosin staining. Through the use of 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, cell viability was detected to observe the cellular resuscitation of the cultured cells following cryopreservation. RESULTS: Twenty-four hours after inoculation, cells began to adhere to the wall, exhibiting short shuttle- or triangle-shaped appearance with different sizes of cellular processes. Three days later, adherent cells began to divide, and cell clusters could be found in some areas; One week later, most of cells exhibited scattered fibroblast-like growth; After passage, cells were evenly distributed with long shuttle-shaped appearance and arranged orderly. Following 3 passages, there wound be 5×106-1×107 adherent cells in 1 mL MSC suspension. Approximately 90% of MSCs survived and identified as mononuclear cells. Cells vigorously grew at days 1-6 after inoculation and reached a peak level at day 8, followed by a viability decline. After 56 days of resuscitation, frozen cells displayed a good and rapid growth. CONCLUSION: Highly purified MSCs can be acquired by gradient centrifugation of lymphocyte separation medium. Enough seeded cells can be obtained by in vitro culture and the cellular viability does not change after frozen preservation and resuscitation.

BACKGROUND: SOX-9 plays an important role in occurrence and development of cartilaginous tissues,enhances agglutination of mesenchymal cells,has structural domains of transcriptional activation,and can directly regulate the transcription,OBJECTIVE: To construct pDC316-SOX-9 plasmid for transfection of rabbit bone marrow stromal cells (BMSCs) using SOX-9 gene,and to investigate the effects of SOX-9 gene on growth characteristics of BMSCs and product expression. DESIGN,TIME AND SETTING: The cell gene engineering in vitro experiment was performe,d at the Beijing Institute of Genome, Chinese Academy of Scienees from June 2006 to January 2007.MATERIALS: Eight SPF New Zealand rabbits aged 6 weeks were used for culture of BMSCs.METHODS: pDC316-SOX-9 plasmid was used for transfection of rabbit BMSCs by liposome mediated method,Cell transfection included a SOX-9 plasmid transfection group,a blank plasmid group and a blank control group (only treatment of liposome). MAIN OUTCOME MEASURES: Cell morphology; growth activity; The SOX-9 protein expression in rabbit BMSCs were detected by immunohistochemistry,hematoxylin-eosin staining,reserve transcriptase-polymcrase chain reaction (RT-PCR) and enzyme-labeled immunosorbent assay (ELISA). RESULTS: Some cell colonies were detected at 4 days after pDC316-SOX-9 plasmid transfection.Spindle-shaped cells were collected after clone amplification.Cells in the blank control group gradually died over time.Cell activities in the SOX-9 plasmid transfeetion group and the blank plasmid group significantly prolonged,reached a peak at 2 weeks of transfection,and then gradually decreased.At 6 days,BMSCs were yellow in the SOX-9 plasmid transfection group following immunohistochemistry,expressing SOX-9 protein.Hematoxyliu-eosin staining showed many dikaryocytes,rich cell proliferation,similar to chondroblasts.No SOX-9 protein expression and unproductive cell proliferation in the blank plasmid group.SOX-9 mRNA was detected in the SOX-9 plasmid transfection group,but SOX-9 mRNA was not detected in the blank plasmid group and blank control group.SOX-9 levels were significantly higher in the SOX-9 plasmid transfection group than in the blank plasmid group and blank control group at 24,48 and 72 hours,1,2 weeks (P＜ 0.01).CONCLUSION: Rabbit BMSCs were successfully transfected with pDC316-SOX-9 plasmid to enhance cell growth activity and to persistently stably secrete SOX-9 protein,resulting in the differentiation of BMSCs into cartilages.

Objective To investigate the clinical effects of bioglue compound and anatomic plate in treatment of tibial plateau fractures. Methods 28 cases of tibial plateau fractures were treated by means of open reduction and internal fixation with bioglue compound and anatomic plate. The intervals between operation and injury ranged from 5 to 10 days. The amounts of bioglue compound implanted ranged from 3 to 8 grams. Results All the patients were followed up for 6 to 22 months. All the fractures healed satisfactorily without sunken joint surface. According to Mechant criteria, the result was excellent in 13 cases, good in 11 cases, moderate in 3 cases and poor in 1 case. The total excellent and good rate was 85.3 %. Conclusion Internal fixation with bioglue compound and anatomic plate can result in good effects in treatment of tibial plateau fractures, because the bioglue compound possesses high bone inductive potentialities to repair bone defects.

Objective To discuss the results of treatment of proximal humeral fractures in elderly patients with a locking proximal humerus plate. Methods 35 aged patients with proximal humeral fracture were treated with a locking proximal humerus plate from January 2001 to January 2004. Early rehabilitation after operation was performed. Results 35 cases were followed up for 13.2 months on the average. The mean time for bony union was 8.3 (7 to 12) weeks. 1 patient developed an avascular necrosis of the humeral head. According to the Constant Score, the average for all fractures was 81.4 (39 to 95). The excellent and good rate was 85.7%. Conclusion The locking proximal humeral plate proves to be safe and can be recommended for the treatment of proximal humeral fracture in elderly osteoporotic patients.

Objective To investigate the effect of fibrin sealant cefazoline sodium implant on prevention and treatment of orthopaedic infection. Methods The fibrin sealant antibiotic implant was made by 10 ml (100 mg/ml) profibrin (Human) mixed with 2.0 g cefazoline sodium, after which 5 ml (200 PE/ml) prothrombin complex concentrate (Human) was added. A total of 24 female New Zealand white rabbits were recruited in the study and divided into three groups, ie, Group A that was implanted with the fibrin sealant antibiotic implant, Group B that was implanted with antibiotic and Group C that was as control. The model of bone infection was made by injecting 0.2 ml(1?10~6 CFU/ml) staphylococcus aureus into the bone hole in tibia of two legs. The histologic and radiologic bone changes were evaluated 2, 4 and 8 weeks after therapy. And in vitro release test was performed. Results There was not evidence of osteomyelitis in Group A, but the osteomyelitis was observed in Groups B and C. Concentration of cefazoline sodium about (1 043.94?0.20) ?g per piece was released from fibrin sealant cefazoline sodium implant within the first 24 hours by in vitro diffusion test but felt to (7.21?0.02) ?g per piece at the 35th day. Conclusion The fibrin sealant cefazoline sodium implant is simple to make and effective in preventing and treating orthopaedic infection as well as in improving repair of the bone defects.

Objective:To study the cytokine mechanism of Jiawei Xuanfei Toujie Ji(JXT)therapy to influenza infected mouse.Methods:Mice were inoculated intranasally with mouse lung-adapted influenza virus strain(FM1),and were treated with JXT. At 5th days after postinoculation were sacrificed, and IL-2,TNF-?,IL-6,IFN-? in their sera were measured with ELISA kits, their lungs sections were stained with hematoxylin and eosin.Results:Compared with model group ,the levels of IL-2 and IFN-? in JXT group were dramatically higher,and the levels of TNF-? and IL-6 were lower,and pathological effects of influenza pneumonia showed less lung injury.Conclusion:Regulative effects on cytokine may be one of the factors that JXT decrease the pathogenesis of influenza-induced acute lung injury.