Embryonic stem cell possess multi-directional differentiation capacity and can differentiate into all sorts of cells of three germ layers,it has the widely use in the treatment of tissue repair.Recent study shows that,embryonic stem cells can differentiate into cartilage cells in the effect of cytokines,hormones,micro-environment etc.In the is review,the author explore several studies and review the effects of different factors to the differentiation of embryonic stem cell to chondrocyte.

Recently,tissue-engineered chondrocyte transplantation has been tried to treat full-thickness cartilage defects.Of the many scaffold materials being investigated,collagen,with good biocompatibility,biodegradable and biological activity,has been shown to have many advantageous features for the proliferation,the attachment and the differentiation.The present article reviews the applications and prospects of collagen in cartilage tissue engineering.

Objective To understand the city residents' iodine nutrition level after implementation of a new iodine concentration standard.Methods Using random sampling,four counties were selected to monitor iodine nutrition level;in every county 50 children aged 8-l0 and 20 pregnant women were selected as monitoring subjects;B ultrasound scan was used to detect goiter and children urinary iodine and salt iodine levels were tested;urinary iodine concentration of pregnant women and nursing mothers was determined.Results Thyroid of 200 children aged 8-10 years were detected,the enlargement rate of thyroid gland was 1％ (2/200);200 salt samples were tested,qualified iodized salt consumption rate was 96％ (192/200);200 copies of children urine samples were tested,the median of urinary iodine was 229.3 μg/L;80 copies urine samples of pregnant women were tested,urinary iodine median was 183.7 μg/L.Conclusions After implementation of a new standard of salt iodine content,the iodine nutrition level of children in the four counties (districts) of Zunyi is still high,but the level of iodine nutrition of pregnant women appears imbalanced.We suggest to supply different concentrations of iodized salt for different groups of people,to strengthen the monitoring,and to prevent iodine deficiency disorders.

[Objective]To discuss a reasonable treatment for unstable intertrochanteric hip fractures in senile patients by comparing the effects of hemiarthroplasty and DHS fixation.[Method]Totally 126 intertrochanteric hip fractures in senile patients with complete clinical data were retrospectively analyzed,who were treated with hemiarthroplasty or DHS fixation from June 2002 to October 2005.Of the 126 patients,53 were treated with hemiarthroplasty,73 were treated with DHS fixation.All of them had multiple medical co-morbidities and were combined with severe osteoporosis.According to modified Even-Jensen classification,all of them belonged to unstable fractures.Comparison was made between the two treated groups in terms of operative time,blood transfusion during or after surgery,time for bed rest postoperatively,postoperative complications and St.Michael hip score one year after surgery.[Result]The average duration of follow-up for hemiarthroplasty and DHS fixation was 16 and 18 months respectively.Compared with the group of DHS fixation,the group of hemiarthroplasty experienced shorter time for bed rest postoperatively,fewer postoperative complications and higher St.Michael score 1 year after surgery,and the differences between two groups had statistical significance(P0.05).[Conclusion]Cemented hemiarthroplasty has the advantages of allowing early full weight bearing after surgery,low complication rate and satisfactory functional recovery.It is a reasonable treatment for unstable intertrochanteric hip fractures in senile patients.

[Objective]To evaluate tho effects of Bone Mesenchymal Stem Cells(BMSCs) on healing of bone-tendon junction in a patellar tendon complex.[Method]The BMSCs of rabbits were harvested by bone marrow aspiration. Adherent cells were selected as BMSCs after the whole marrow was cultured.Standard partial patellectomy was conducted in 36 18-week-old rabbits divided into 2 groups. The experimental group was planted into by the composite of BMSCs and Pluronic F-127 while the control group was only operated without BMSCs planting into.The patellar-patellar tendon complexes were harvested at weeks 6,12,18 postoperatively for radiographic, gross and histological evaluations.[Result]Radiographic measurements showed significantly more newly formed bone at the patellar tendon-patellar healing junction in the experimental group compared with that of the controls at weeks 6,12,18(P

[Objective]To investigate the feasibility of the fabrication of tissue-engineered anterior cruciate ligament(ACL)in vitro by studying biocompatibility and mechanical property of the braided polyvinyl alcohol(PVA)materials.[Method]Firstly,human ACL cells and NIH3T3 cells were isolated,expanded in vitro and seeded onto the surface of the braided PVA scaffold materials,the adhesion,proliferation and three-dimensional growth of cells on the scaffold were observed by SEM.Secondly,the biomechanical properties of the braided PVA scaffold materials were measured with electro-biomechanical machine.[Result]The braided PVA scaffold materials had no cytotoxicity,ACL and NIH3T3 cells adhered,grew and proliferated well both on the surface and in the holes of the braided PVA scaffold materials.The maximum load,the maximum strain and ultimate tensile stress of the braided PVA scaffold materials respectively were 169.78?9.18N,11.67?1.38% and 52.21?2.88MPa.[Conclusion]The braided PVA scaffold materials possess good biomechanical properties and biocompatibility,it may become an ideal biomaterial for fabricating tissue-engineering ACL if the biomechanical properties can be improved.

[Objective]Porous collagen type Ⅱ matrices crosslinked by 1-ethyl-3-(3-dimethyl aminopropyl)carbodⅡmide(EDC) and N-hydroxysucinimide(NHS) were developed as scaffolds for cartilage tissue engineering.[Method]Collagen type Ⅱ matrix was crosslinked by EDC/NHS,and then freeze-dried to achieve collagen scaffolds.The porous characteristics of the prepared scaffolds were tested by using diffenent methods,including laser scanning confocal microscopy (LSCM),scanning electron microscopy (SEM) and mechanical testing machine.The chondrocytes labeled by GFP were planted in crosslinked collagen type Ⅱ,and observed by LSCM.[Result](1) The mechanical properties of cross-linked matrices increased significantly,reaching 2.18?0.47MPa.(2)The degradation of cross-linked matrices decreased by 8.28% after 4 hours.The pore size was about 90?m,and their average porosity and water capacity reached 93.39% and 97.78%,respectively.3.Chondrocytes were in good condition in the crosslinked collagen.[Conclusion]The present work indicates that EDC/NHS-crosslinked collagen type Ⅱ could keep the properties and biocompatibility of collagen,besides,the mechanical strength increased and the degradation was decreased.It will be suitable for cartilage tissue engineering purposes.

Objective To discuss the surgical approaches t o treat the 3-and 4-part-fractures of the proximal humerus in young adults.Methods Open reduction,internal fixation with T-shaped steel plate or together with tension band wire,repair of rupture d rotator cuff and joint capsule were conducted.Early rehabilitation wa s performed after the operation.Results8cases were followed up for 1to 4years,with an average of 3years.The functional recovery of the injured shoulder joint had an excellent result of 87.5%.Conclusions Internal fixation with T-shaped steel plate or together with tension band wire to treat the 3-and4-part-fractures of the proximal hu merus in young adults can better the function al recovery of the shoulder joint,as long as used properly,because it is s table and eliminates the need of postoperativ e external fixation so that function al exercises can be done earlier.

Objective To assess the clinical value of the mi nimally invasive plate fixation technique in treatment of metaphyseal comminute d fractures of long tubular bones.Methods Sixty-eight patients with metaphyseal comminuted fractures o f femur or tibia were treated with min imally invasive percutaneous plati ng and early recovery movement from April 1999to October 2001.Results All the patients were followed up for a mean time of 10months.The postopera tive radiograph showed that reducti on and internal fixation were satisfactory in sixty-five patients.Lateral angular deformity of 8?occurred in one c ase,and 2cm shortage of the lower lim b in two cases.Sixty-eight patients obt ained bone union and satisfactory clinical function.There were no deep i nfec-tion,nonunion or other complicatio ns.Conclusion For metaphyseal comminuted fractur es of long bones of lower extremities,minimally invasive percutaneous plate fixation is o f significant value due to the advant ages of less iatrogenic trauma,rigid fixation and early movement.[

Objective To discuss our tentative application of the anatomic plate in the treatment of distal tibia fractures in order to develop a new effective fixation technique for this kind of fracture. Methods From November 2000 to September 2001, the authors applied Linkdistal tibia anatomical plates in the treatment of distal tibia fractures, which involved metaphysis in 12 cases, including 8 males and 4 females, aged from 18 years ～66 years, with 38 years on average. All the cases were of high energy injuries and complicated with ipsilateral fibular fracture. According to AO/ASIF classification: three were type A1, five were A2, three were A3, and one was B1; three of them were close fractures, five were type IO1 open fractures, and four were IO2. Results All the cases healed at one stage without infection or exposure of the implant. Bone callus could be found 2 3 weeks after operation. Bone union was achieved within 3～6 months, with 4 months on average. No delayed union or non union occurred. Functions of ankle joints recovered completely. Conclusion The anatomical plate for distal tibia is supperior to the traditional plates in both biomechanical and biological aspects. It is the best choice for the treatment of distal tibia fractures.