Objective Currently, the effect of hydrogen peroxide solution( H2 O2 ) flush on the recovery of peripheral nerve injury are still undetermined. This study aims to explore the effects of different H2 O2 flushing time course on recovery of peripheral nerve injury during surgical debridement. Methods 18 New Zealand male white rabbits were randomly divided into isotonic saline group( isotonic saline flush) , H2 O21 min group ( hydrogen peroxide solution flush 1 min + isotonic saline flush) , H2 O23 min group ( H2 O2 flush 3 min + isotonic saline flush. Each group has 6 rabbits. We established rabbit sciatic nerve injury model. After 12 weeks, we executed the animals, drew materials at the suture nerve, detected motor nerve conduction velocity and observed pathological HE staining, as well as measuring the sciatic nerve function indexes( SFI) of rabbits at the 8th and 12th week, respectively. Results Nerve conduction velocity in H2O21min group and isotonic saline group[(25.89±1.42), (26.46±1.67) m/s] were higher than that in the H2O23min group[(23.80±2.91)m/s](P<0.05). Pathological section shows that the isotonic saline group has a better sheathstructure, nerve fibers structure damage is not obvious and myelin degeneration degree is mild in H2 O21 min group. blurred sheath structure and myelin axons obvious deformation in H2 O23 min group. 8 weeks and 12 weeks after operation, SFI in isotonic saline group [(-43.00±0.82), (-39.17±0.91) m/s] was significant higher than H2O21 min group [ (-49.79±1.47), (-46.60±0.79) m/s] and H2O23min group [(-51.66±1.27), (-46.39±0.94) m/s], thedifference was statistically significant (P<0.05). SFI in group of H2O21min [(-49.79±1.47)m/s] was higher than group og H2O23 min [(-51.66±1.27) m/s][P<0.05]. Conclusion H2O2 solution has side effect on the recovery of damaged peripheral nerve inju-ry and with prolonging the H2 O2 flushing time, the damage of peripheral nerve can be aggravated. So in the process of clinical surgical debridement, under the premise of guaranteed sterilization the time of H2 O2 flush should be shortened as far as possible.

Objective:The aim is to establish L-glutamate specific aminotransferase-L-glutamate dehydrogenase coupling 96-well high throughput screening method,which is applied to molecular evolution of aminotransferase WecE from E.coli.Methods:An optical assay for aminotransferase catalytic activity based on aminotransferase-glutamate dehydrogenase coupling system is established by optimization of coupling enzyme loading,signal molecule NADH concentration and coupling time.Mutants library of WecE is obtained by sitedirected saturation mutagenesis.Positive mutants can be screened out through 96-well preliminary screening and flask second screening.Results:The target transamination reaction is coupled with L-glutamate dehydrogenase indicative reaction system which consists of 0.5 U/ml enzyme loading and 0.4 mmol/L NADH.A positive mutant Y321F whose catalytic activity increases 3.4 fold compared to that of wild type is screened out in Tyr 321 saturation mutagenesis library of WecE.Conclusion:An accurate high throughput screening method with weak background interference is established.It offers feasible solution for molecular evolution of L-glutamate specific aminotransferase.

Composite Resins ; therapeutic use ; Dental Restoration, Permanent ; methods ; Humans

Objective:To evaluate the clinical effects of short fiber ribbon combined with resin bonding technology for the treatment of food impaction between posterior teeth. Methods:98 cases of vertical food impaction between posterior teeth( total of 135 vertical food impaction units) were included. 73 units were treated by short quartz fiber ribbon combined with resin bonding technology( SQFRB) and 63 by resin bonding(RB). 12, 24 and 36 months after restoration, clinical effects were evaluated referring to the Modified United States Public Health Service (USPHS) Criteria, data were statistically analyzed. Results:12, 24 and 36 months after treatment the cure rate of SQFRB was 97. 3%, 97. 3% and 95. 9%, inefficacy rate was 0, 0 and 0;the cure rate of RB was 85. 5%, 82. 2% and 82. 2%, the inefficacy rate was 4. 8%, 11. 3% and 12. 9%, respectively(between groups, P<0. 05). Conclusion:Minimally inva-sive restorations using short fiber ribbon combined with resin bonding technology is effective in the treatment of vertical food impaction between posterior teeth.

Objective To investigate the value of serum receptor activator of nuclear factor kappa B ligand (RANKL)/osteoprotegrin (OPG) ratio in osteoporotic fracture (OPF) of patients with rheumatoid arthritis (RA).Methods Three hundred and eighty four RA patients with mean age of (49 ± 14) y (16-82) admitted in the First Affiliated Hospital of Anhui Medical University from 2010 to 2013 and 158 sex-and age-matched healthy subjects were enrolled in the study.OPF was diagnosed by X-ray examination and BMDs of femur and lumbar spine 2-4 (L2-4) were measured by dual energy X-ray absorptiometry.Levels of RANKL and OPG in the peripheral blood of 220 RA patients and 100 normal subjects were detected by ELISA method.Results Eighty-two cases of OPF was diagnosed in 384 RA patients (21.35％),the rate was higher than that in controls (3.80％,6/158,x2 =25.371,P ＜0.01).The peripheral blood levels of RANKL (0.150 ± 0.143 vs.0.101 ± 0.066,t =4.178,P ＜ 0.01),OPG (0.457 ± 0.293 vs.0.359 ±0.216,t=3.347,P=0.001) and ratio of RANKL/OPG (0.41 ±0.35 vs.0.34±0.20,t =2.111,P=0.036) in RA patients were significantly higher than those in control group.In comparison with normal controls,BMDs of all detected regions in RA were decreased significantly (P ＜0.01).The incidence of osteoporosis in RA (121/327,37％) was higher than that in normal controls (22/158,13.92％) (x2 =27.291,P ＜ 0.01).RA patients with OPF had higher age (t =4.377,P ＜ 0.01),longer duration of disease (t =2.612,P =0.009),higher RANKL level (t =3.554,P =0.001),higher RANKL/OPG ratio (t =2.651,P =0.010),higher health assessment questionnaires (HAQ) score (t =2.418,P =0.016),lower serum calcium level (t =2.183,P =0.030),lower hemoglobin level (t =2.125,P =0.036),higher Sharp score in hands X-ray examination (t =2.747,P =0.007),worse X-ray stage (x2 =7.856,P =0.049),higher glucocorticoid utilization rate (x2 =9.066,P =0.003) and higher incidence of osteoporosis (x2 =38.186,P ＜ 0.01),compared with patients without OPF.RA patients taking corticosteroids had higher incidence of osteoporosis (x2 =7.489,P =0.006) and higher incidence of OPF (x2 =9.066,P =0.003).Logistic regression analysis showed that age (OR =1.029,P =0.039,95％ CI:1.001-1.057)and the occurrence of osteoporosis (OR =3.159,P =0.001,95％ CI:1.562-6.385),RANKL/OPG ratio (OR =3.516,P =0.013,95 ％ CI:1.305-9.647) were risk factors for RA patients with OPF.Conclusion A higher incidence of OPF is prevalent in RA patients,and age,osteoporosis,taking glucocorticoids and RANKL/OPG ratio are risk factors for OPF in RA patients.

BACKGROUND:Several researches have highlighted the selective dissolution of Ni ion from the nickel-titanium (NiTi) alloy during the corrosion process,which can lead to potential damage to human body.Different surface treatments will improve the corrosion resistance of NiTi implants.In modern medicines,it is necessary to analyze the characteristics of surface modified NiTi implants.OBJECTIVE:To study the effects of coated and uncoated materials made by elastic nickel-titanium alloy internal fixator on fracture healing and to compare the effects of continuous compressive stress after internal fixator of different types on fracture healing by setting up control group of bone nail internal fixation.DESIGN,TIME AND SETTING:A randomized,controlled,animal experiment was performed at the Laboratory of Tissue Engineering,Institute of Orthopedics,Second Hospital Affiliated to Lanzhou University between September 2004 and March 2005.MATERIALS:Diamond-like carbon coated and nickel-titanium alloy and uncoated nickel-titanium alloy embracing fixator (type 4H8-40) were provided by Lanzhou Ximai Memory Co.,Ltd.,China.Intramedullary nails (type ZQY-01) were purchased from Tianjin Jinxingda Industries Co.,Ltd.,China.METHODS:Thirty Chinchilla rabbits of 4-6 months old were randomly divided into 3 groups (n = 10):diamond-like carbon coated nickel-titanium alloy embracing fixator (group A),uncoated nickel-titanium alloy embracing fixator (group B),and intramedullary fixator (group C).Following anesthesia by injection of 1% sodium pentobarbital (25 mg/kg),transverse fracture models in middle part of the femur were made through a lateral femoral incision and fixed with diamond-like carbon coated nickel-titanium alloy embracing fixator,uncoated nickel-titanium alloy embracing fixator,and intramedullary fixator respectively.MAIN OUTCOME MEASURES:The inorganic substance level,osteocalcin,alkaline phosphatase (ALP) and tumor necrosis factor (TNF) expression in callus surrounding fracture site were detected 4 weeks postoperatively.Ni ion level in muscles surrounding fracture site,live tissue,and brain tissue were also detected.RESULTS:Inorganic substance level and ALP,osteocalcin,and TNF expression were significantly higher in the groups A and B than in group C (P＜0.05).Ni ion level in the liver tissue,brain tissue,and muscles surrounding the fracture were significantly lower in the groups A and C than in group B (P＜0.05).CONCLUSION:Elastic fixation promotes fracture healing.Diamond-like carbon coated nickel-titanium alloy embracing fixator has a better histocompatibility than uncoated group.

Objective To explore the prevalence of osteoporosis (OP) and vertebral osteoporotic fracture (OPF) and related risk factors in patients with rheumatoid arthritis (RA).Method A total of 644 patients with RA from Jan.2010 to Oct.2013 were recruited,anteroposterior and lateral X-rays examination of vertebral column (T5-L5) were conducted,and semi-quantity method were used as the standard for judging vertebral OPF.Meanwhile,patients' clinical and laboratory data including daily dosage of glucocorticoid,duration of glucocorticoid usage,cumulative amount dosage of glucocorticoid were recorded in details.158 normal subjects were selected as control group.Results (1)The prevalence of vertebral OPF in patients with RA was 16.6％.Bone mineral density (BMD) of all measured lumbar vertebra in RA group were markedly decreased[(0.97 ±0.22) g/cm2].The total prevalence of OP at lumbar vertebra in RA was 17.9％ (81/452),which was significantly higher than that of control group (4.4％,7/158) (P ＜ 0.001).(2) The percentage of OP in RA patients with vertebral OPF was significantly higher than that in patientswithout OPF [40.6％ (41/101) vs 11.4％ (40/351) ;P ＜ O.001].Patients with OPF were of older age,longer use of glucocorticoid,more cumulative amount dosage of glucocorticoid,longer disease duration,higher scores of health assessment questionnaires (HAQ) and increased ESR (P ＜ 0.05).(3) Logistic regression analysis revealed that age (OR =1.094,95％ CI 1.065-1.125,P ＜0.001) and gender(1 =male,2 =female) (OR=5.600,95％ CI 2.097-15.087,P =0.001) were the risk factors for the development of OP in RA,while body mass index (BMI) was the protective factor (OR =0.770,95％ CI 0.696-0.853,P ＜ 0.001).Age (OR =1.031,95％ CI 1.009-1.053,P =0.005) and occurrence of OP at lumbar vertebra (OR =3.765,95％ CI 2.092-6.776,P ＜ 0.001) were risk factors of the development of OPF in RA patients.Logistic regression analysis also showed that RA was the risk factor of OPF (OR =4.716,95％ CI 1.987-11.192,P ＜ 0.001),even after the adjustment of age,gender and BMI.(4) Receiver operator characteristic(ROC) curve in RA patients with OPF has found that age-OPF and daily dosage of glucocorticoid-OPF AUCRoC were 0.689 and 0.636 respectively.The cut-off value in ROC curve of age and daily dose or treatment course of glucocorticoid-OPF were 54.5 years and 6.25 mg(P ＜0.001),while duration of glucocorticoid usage-OPF AUCROC was 0.685,with cut-off value in ROC of age-OPF 135 days(P ＜ 0.001).Conclusion Prevalence of OPF in patients with RA increases remarkably.Old age and OP at spine are risk factors related to the development of OPF in patients with RA.

BACKGROUND: Although shape memory alloy has been extensively used in modem medicine, including orthopaedics and dental surgery, the body fluid could influence the stability of biomaterial and some ions released by materials may cause toxic and side effect to human body. The technology for the modification of shape-memory materials is of crucial importance for clinical use of shape memory alloy.OBJECTIVE: To investigate the biocompatibility of diamond-like carbon (DLC) coated Nickel-Titanium shape memory alloy and uncoated shape memory alloy with osteoblasts cultured in vitro. DESIGN, TIME AND SETTING: A comparative observation. The study was performed at the Institute of Othopaedics of Lanzhou University from March to June 2005.MATERIALS: A total of 30 DLC-coated Nickel-Titanium shape memory alloy disks, 6 minx7 mmx0.5 mm, and the same amount of uncoated ones of equal size were provided by College of Materials, Lanzhou University. METHODS: Rabbit osteoblast suspension of the third passage at density of 10 × 108/L were incubated with DLC-coated Nickel-Titanium shape memory alloy disks and uncoated shape memory alloy in 12-well culture plate in 5% CO2 at 37 ℃.MAIN OUTCOME MEASURES: Culture media were counted at 1, 2, 3, 4 and 5 days of culture to determine alkaline phosphatase (AKP) activity and nickel (Ni2+) concentration.RESULTS: The proliferation of osteoblasts and the concentration of AKP in DLC- coated group were greater than uncoated group; while the uncoated group released more Ni2. into the cells culture media than coated group (P < 0.05). CONCLUSION: DLC-ceated Nickel-Titanium shape memory alloy appears to have better biocompatibility with osteoblast cultured in vitro compared to uncoated ones.

Objective To examine the plasma β-catenin and DKK1 levels in patients with rheumatoid arthritis (RA) and to explore their relationship with bone and joint damage in RA.Methods One hundred and thirteen patients with RA and 120 healthy individuals were recruited into this research.Bone mineral density (BMD) in the femur and lumbar spine were measured with dual-energy X-ray absorptiometry (DEXA).Radiographs for two hands were evaluated according to the Sharp's method.Serum levels of β-catenin and DKK1 in all patients with RA and healthy controls were detected by enzyme-linked immunosorbent assay (ELISA).The 2-tailed independent samples t test was used for measurement data.Chi-square test was used for the enumeration data.Correlation analysis,linear regression and Logistic regression analysis were used as appropriate statistical analysis.Results ① Significantly higher serum levels of DKK1 were observed in RA patients than that in healthy controls [(8±7) vs(6±4) μg/ml,t=2.552,P=0.012],while there was no sinnificant difference with regard to the levels of β-catenin between the two groups.② Compared to control groups,patients with RA had lower BMDs at femur and lumbar spine (P＜0.01).Furthermore,incidence of osteoporosis (OP) in RA (31.9％,36/113) was remarkablely higher than that in healthy subjects (15.0％,18/120) (x2=9.290,P=0.002).③ There were obvious discrepancies in age,swollen joint count (SJC),swollen joint count index (SJI),alkaline phosphatase (AKP),joint narrowing space score,joint erosion score,Sharp score between patients with osteoporosis and without osteoporosis (P＜0.05).④ In RA group,DKK1 level was posi-tively related with plasma erythrocyte sedimentation rates (ESR),28-jonit disease activity score (DAS28),AKP,joint narrowing space score (P＜0.05).Serum β-catenin level was associated with ESR,AKP in RA (P＜0.05).⑤ Multiple linear regression analysis indicated that in the RA group,disease duration (b=0.709,t=9.560,P＜0.01,95％CI:2.154-3.286),HAQ (b=0.151,t=2.052,P=0.043,95％CI:0.234-15.243),DKK1(b=0.286,t=2.057,P=0.043,95％CI:0.034-2.028)were the contributors for joint space narrow score(R2=0.580,F=24.745,P＜0.01).⑥ Multiple Logistic regression analysis showed that the Sharp score (OR=1.018,P＜0.01,95％CI:1.008-1.028) was the risk factor for the occurrence of osteoporosis at femur in RA,while age (OR=1.087,P=0.012,95％CI 1.019-1.159) was the risk factor for osteoporosis at lumbar spine.Conclusion Serum DKK1 levels in RA increase significantly,while there is no apparent alteration in plasma β-catenin.Serum DKK1 is correlated with disease activity and joint space narrow score.

BACKGROUND: As an ideal scaffold of cartilage tissue engineering, demineralized bone matrix (DBM) has been widespread used. But some of biological characters remain poorly understood.OBJECTIVE: To determine the degradation capacity, interval porosity and adhesion rate of mesenchymal stem cells (MSCs) onto DBM in vitro.DESIGN, TIME AND SETTING: An observation experiment in vitro was complicated in Institute of Orthopedics, Second Hospital of Lanzhou University from January 8~(th) to April 15~(th) in 2005 and Central Laboratory of Guilin Medical University from August 1~(st) to November 15~(th) in 2007.MATERIALS: One chinchilla rabbit was killed under anesthesia. Referring to the method described by Urist, DBM was made by cancellated bone harvested from metaphysis and vertebral body METHODS: DBM was soaked into phosphate buffered solution to determine its degradation capacity; liquid replacement method was used to test its interval porosity; The 3~(rd) passage MSCs at a concentration of 1×10~8/L were cocultured with DBM in vitro and adhesion rate of MSCs onto DBM was tested using cytometry.MAIN OUTCOME MEASURES: The degradation capacity, interval porosity and adhesion rate of MSCs onto DBM.RESULTS: The degradation rate of DBM was accelerated with the prolonging of time, and the complete degrading time was about 10-12 weeks; The holing rate tested was (77.15±3.44)%; The 3~(rd) passage cells had a higher adhesive rate of 71.25% onto DBM.CONCLUSION: DBM degradation curve is consistent with MSCs proliferation curve, indicating a satisfactory adhesion capacity and interval porosity and DBM is an ideal biological scaffold material for cartilage tissue engineering.