Objective To investigate the mutations of epigenetic regulation factor ASXL1 gene in myelodysplastic syndrome(MDS).Methods Mutation analysis of ASXL1 gene in 53 de novo MDS patients and 20 healthy persons was performed by using polymerase chain reaction(PCR)followed by sequence analysis at DNA level.The clinical and laboratory characteristics were compared in MDS patients with ASXL1 gene mutation and ASXL1 wild type.ASXL1 mutation in mRNA level was detected by using reverse transcription PCR(RT-PCR)followed by sequence analysis.Results ASXL1 gene mutations were observed in 9 cases(16.9%)of 53 MDS patients.6 mutation types were detected,including 4 frameshift mutations types(2 cases with p.Glu635ArgfsX15,3 cases with p.Gly646TrpfsX12,1 case with p.Ala640GlyfsX14 and 1 case with p.Gly790TrpfsX10)and 2 nonsense mutation types(1 case with p.Gln1063X and 1 case with p.Gln695X).All the mutations were heterozygous,and p.Gly790TrpfsX10 and p.Gln695X were new mutation types.In addition,a single nucletide polymorphism(SNP)p.Gly652Ser was also detected in 4 cases with MDS.5 cases of p.G652S SNP and 1 case of p.Leu1173Leu SNP were detected in 20 healthy people.Frameshift mutation(p.Gly646TrpfsX12)could be detected at mRNA level by using RT-PCR.Differences were not observed in red blood cell counts,white blood cell counts,platelet counts,hemoglobin levels,reticulocyte,neutrophil granulocyte,the peripheral blood lymphocytes percentage,T-cell subsets in the peripheral blood,the proportion of primitive cell in the marrow and MDS types between the patients with ASXL1 gene mutation and ASXL1 wild type patients(P >0.05).Conclusion There is a high frequency of ASXL1 gene mutation in MDS patients,which can be detected at mRNA level.

Objective: To investigate the effect of biology and mTOR pathway activity of down-regulated TSC2 gene expression on U937 leukemia cells. Methods: Gene expression was down-regulated by lentivirus induced RNA interference on TSC2 high expressed U937 cell line; the proliferation, apoptosis and differentiation were detected by CCK-8 assay, colony formation assay and flow cytometry; the gene expression level and protein kinase activity were detected by qRT-PCR and Western blot. Results: Down-regulated expression of TSC2 gene promoted U937 cell proliferation and colony formation ability (P<0.05) . The proportion in G₀/G₁ phase of TSC2 down-regulated U937 cell was much lower than that of the control cells [ (52.53±3.75) % vs (75.10±4.33) %, t=6.829, P=0.002], the S phase [ (22.43±1.00) % vs (15.47±1.20) %, t=-5.581, P=0.019] and G₂/M phase [ (25.03±4.34) % vs (14.33±0.91) %, t=-5.413, P=0.013] was remarkably higher than that of the control cells (P<0.05) . There were no statistically significant differences in cell apoptosis and differentiation (P>0.05) . Down-regulation of TSC2 led to the increased activity of mTOR, 4EBP1 and S6K1, but did not influence the activity of AKT. The expressions of proliferation related cyclinD1, c-myc and PTEN were also up-regulated after TSC2 silenced, but the expressions of P27KIP and BCL-XL were not changed. Conclusion Downregulation of TSC2 could promote the proliferation of U937 cells through up-regulation of mTOR activity.

Objective To investigate the effect of overexpression of cartilage oligomeric matrix protein (COMP) on BMP-2 induced cell osteogenic and chondrogenic differentiation of mesenchymal stem cells (MSCs).Methods MSCs,transfected with plasmid DNA encoding recombinant human COMP,were induced to differentiate into osteocytes and chondrocytes by BMP-2.Realtime PCR of osteogenic related markers (Col1a1,RUNX2,OPN,BGP) and chondrogenic related markers (Col2a1,SOX9,Aggrecan) were performed to evaluate the process of cell differentiation.ALP staining,Alizarin red S staining for osteogenic differentiation and alcian blue staining for chandrogenic differentiation were conducted to evaluate the tendency of cell differentiation.Results Real-time PCR assay presented the significantly higher (P＜0.05) COMP expression of MSCs when COMP gene was transfected into cells.The expression level of OPN was significantly (P＜0.05) down-regulated at all the time points in experimental group compared with that in control group.A final significant (P＜0.05) up-regulation of expression appeared in experimental group at the late stage of induction (day 7,14) compared with that in control group,even though a decrease (P＜0.05) expression of Col1a1,RUNX2 and BGP in experimental group occurred at the early stage of induction (day 3).The expression of Aggrecan and Col2a1 in experimental group was up-regulated (P＜0.05) at different time points compared with that in control group.And a significant higher (P＜0.05) expression of SOX9 in experimental group only appeared at day 7 compared with that in control group.ALP staining and Alizarin red S staining were weakened while alcian blue staining was enhanced.Conclusion COMP may inhibit BMP-2 induced osteogenic differentiation and promote BMP-2 induced chondrogenic differentiation,which may provide new insight for cartilage tissue engineering.

Objective The article was to evaluate the efficacy of intra-articular tranexamic acid injection in reduction of blood loss and blood transfusion in total hip arthroplasty (THA). Methods 60 patients hospitalized from July 2011 to July 2013 were selected as research subjects , among whom 38 males and 22 females with 2-10 years'( an average of 6 years) duration of femoral head aseptic necrosis were treated with initial unilateral THA using the posterolateral approach .The patients were randomly divided into 2 groups:experimental group were treated with 100 mL intra-articular tranexamic acid injection after intraoperative suture of incision , control group received no topical tranexamic acid .Intraoperative blood loss , postoperative visible blood loss , blood transfusion , blood transfusion number , postoperative hemoglobin were taken as evaluation indexes to make comparison between the two groups . Results No significant differences were found in intraoperative blood loss between the two groups ( [ 200 ±60 ] mL vs [ 200 ±53 ] mL, P >0.05), but in comparison to control group, postoperation visible blood loss([140 ±45]mL vs [362 ±53]mL, P<0.05), blood transfusion([400 ±25]mL vs [750 ±50]mL, P<0.05) and blood transfusion number in group A were significantly decreased (P<0.05), and in terms of postoperative hemoglobin value ([95 ±15]g/L vs [81 ±12]g/L, P<0.05), experimental group was signifi-cantly higher than control group(P<0.05). Conclusion Topical tranexamic acid in total hip arthroplasty can significantly lower blood loss and blood transfusion in patients .

Objective To explore the clinical significance of retrograde access for the interventional treatment of lower extremity arterial occlusive diseases when the occluded segment of lower extremity artery could not be reached through antegrade access.Methods Twenty-seven cases (male 17,female 10; age range 32-89 years ) were retrospectively investigated, including 18 with lower limb arteriosclerosis obliterans,7 with diabetic foot and 2 with thromboangiitis obliterans.According to the Fontaine staging,6 cases were classified as Fontaine Ⅱ,11were classified as Fontaine Ⅲ and 10 were classified as Fontaine Ⅳ.All cases underwent endovascular operation through antegrade access first with an attempt to cross the occlusive segment,but in vain.So retrograde access was tried via puncture of pedis dorsalis or posterior tibial artery or exposure of lateral branches of posterior tibial artery,peroneal artery or dorsal artery by open surgery,which followed by Percutaneous transluminal angiography and (or) stenting.Results The operation through retrograde access was successful in all cases with obvious improvement of ischemic symptoms.Hematoma at the puncture site occurred in 3 patients,and paresthesia of toes occurred in 1after dorsalis pedis arteriotomy.No severe perioperative complication occurred.The average ankle brachial index increased from 0.37 ± 0.11preoperatively to 0.85 ± 0.12 postoperatively.Conclusions Retrograde access could be used as an alternative strategy in lower extremity arterial occlusive diseases when the occluded segment could not reach through antegrade access.

Objective To investigate the advantages of the external fixators used in the treatment of pelvic fracture. Methods From April 2002 to July 2008, 55 patients with unstable pelvic fracture were treated respectively with simple external fixators, external fixators plus traction and external fixators plus in-ternul fixation according to their different Tile classifications. Results Of this group, 51 cases were followed up for an average of 11 months, 2 cases died because of multi-injuries, and 2 cases were lost in the follow-up. All of the 51 patients obtained bony union. On average, it took 11 (6 to 14) weeks to achieve weight-bearing walking, and 12 (8 to 14) weeks to remove the external fixators for the patients. By Liu Li-ming's evaluation system, the good to excellent rate was up to 88.2%. Conclusions The pelvic fractures of Tile B1 and B2 can be treated with simple external fixators and those of Tile C with external fix-ators plus internal fixation or traction to achieve fracture reduction and stability of the pelvic ring. For the patients with multi-injuries, external fixators used in the emergency treatment can stabilize the pelvic ring, reduce blood loss and improve the success rate.

BACKGROUND: Calcium sulfate (CS) is a good bone conduction material due to its good biocompatibility and degradability. However, simple CS lacks of osteoinductive capability, so it can not satisfy clinical requirements.OBJECTIVE: To verify the potential ofCS/bone matrix gelatin (BMG) composite biomaterial in the repair of segmental bone defects.DESIGN, TIME AND SETTING: An in vivo multi-dimensional observation was performed in the Laboratory Animal Center, Nanfang Hospital, Southern Medical University between December 2004 and April 2006.MATERIALS: Twenty-one healthy adult New Zealand rabbits, weighing 2.5-3.5 kg, were included. The segmental ulnar defects of 15 mm were created bilaterally. CS and BMG were self-prepared.METHODS: CS and BMG were composited at 2:1 and then implanted into 15-mm rabbit ulnar bone defect. The present study consisted of 3 groups: CS/BMG group, defects were filled with CS/BMG; CS group, defects were filled with CS; and blank control group, untreated control defects.MAIN OUTCOME MEASURES: At weeks 4, 8, and 12 post-surgery, repair of bone defect was observed by gross observation, radiographic, histomorphological and tetracycline tracing analysis.RESULTS: Surgical incisions all primarily healed. No inflammatory or foreign reaction was found around all the defects. Both CS/BMG and CS were almost completely absorbed at week 8 post-surgery. In the CS/BMG group, newly formed bone was found throughout the defects after 4 weeks; all defects were repaired with a well-organized trabecular pattern and a thit neocortex after 12 weeks. In the CS group, mass of new bone tissue formed at the periphery of the defect at week 4 post-surgery, but the development of new bone in the center of defect was latter compared with the CS/BMG group: at 12 weeks, all defects were bridged by newly formed bone tissue with little adjacent medullary bone. In the blank control group, slight new bone was found at the periphery of the defect region, and the defects were filled with fibrous tissue.CONCLUSION: CS/BMG composite is totally bioresorbable and biocompatible. The composite can repair bone defects effectively as a bone graft substitute.

[Objective] To investigate the osteogenetic effect of calcium sulfate(CS)combined with bone matrix gelatin(CS)as bone substitute material in a rabbit ulnar defect model.[Method]Twenty one adult New Zealand White rabbits were used.The segmental ulnar defects of 15 mm were created b/laterally and were divided into tbree groups:Group 1,defects were filled with CS/BMG;Group 2,defects were filled with CS;Group 3,untreated control defects.The samples were harvested at 4,8,12 weeks and were examined by radiographic,histomorphological and tetracycline tracing analysis.[Result]No inflammatory or foreign body reaction was observed around all the defects.Both CS/BMG and CS were almost completely resorbed 8 weeks postoperation.At the group 1,nem bone was found throngbout the defects after 4 weeks.All defects were repaired with a well-organized traheeular pattern and a thin neocortex after 12 weeks.At the group 2,mass of new bone tissue formed at the periphery of the defect 4 weeks postoperatlon,but the development of new bone at the central of the defect was latter than that at the group 1.At 12 weeks,all defects were bridged by new bone tissue with little adjacent medullary bone.At the group 3,slight new bone was observed at the periphery of the defect region,and the defects were filled with fibrous tissue.[Conclusion]Calcium sulfate containing bone matrix gelatin is totally bioresorbable and biocompatible.The compound material can enhance the repair bone defects effectively as a bone graft substitute.

[Objective] To investigate the results and to evaluate the validity of the supracondylar femoral osteotomy and internal fixation for treatment of flexion deformity of the knee joint in adult polio patients.[Methods]From April 2002 to August 2008,141 knees in 127 cases with flexion deformity of knee from poliomyelitis were treated with supracondylar femoral extension osteotomy and internal fixation.They were 14~45 years old with an average of 18.3.Of them,62 knees in 56 cases were male,79 knees in 71 cases were female.Eighty-three cases needed pressing knee on walking.Thirty-five cases walked with a crutch and 9 cases walked with two crutches.It should be treated with soft tissue release and skeletal traction before osteotomy in severe flexion deformity(over 40 degrees).All cases took weight-bearing X-ray films of lower extremities before and after operation.Angle of knee flexion,operative complications,bone healing and final function were recorded.Patients can undertake continuous passive flexion and extension motion from the 2nd day postoperatively.The knee operated was put in 10~20? flexion after operation and extended to full extension gradually in 2 weeks.[Results]All patients felt comfortable after operation and no neurovscular complications and infection happened.Follow-up time was 12-72 months with an average of 18 months.Solid bone union showed in all femoral cutting ends.No mal-union,non-union and implant failure happened.All flexion deformities of knees were corrected.The angle of flexion contracture of knee was from 36.4?(18?～61?)preoperatively to 2.8?(-5?～8?)postoperatively.The amount of correction was 18?to 56?with an average of 32.9?.One hundred and eight patients can walk stably by hinself or with brace,19 cases still need some help for walking(pressing knee in 6 case,one crutch in 10 cases and two crutches in 3 cases)at last follow-up.No ankylosis of knee joint or peroneal nerve paralysis occurred.All cases were satisfying with their range of motion of knee.[Conclusion]Supracondylar femoral osteotomy and rigid internal fixation and early rehabilitation exercise is a safe and effective strategy for the adult flexion deformity of knee joint.