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 To investigate the effects of metal particles produced by metal prosthesis on oxidative stress levels in human mononuclear cells . Methods Mononuclear cells obtained from peripheral blood of 15 healthy volunteers .Coculture mononu-clear cells with iron particles , cobalt particles , chromium particles , titanium particles and physiological saline , respectively .Levels of reactive oxygen species ( ROS) , malondialdehyde ( MDA) , superoxide dismutase ( SOD) and glutathione peroxidase ( GSH) were as-sessed in mononuclear cells at 6 h, 12 h, 24 h, 36 h, 48 h, respectively . Results Levels of ROS and MDA were higher in the parti-cle groups than that in the control group at 6 h, 12 h, 24 h, 36 h, 48 h, respectively (P<0.05).Levels of ROS and MDA were higher in cobalt particle, chromium particle and iron particle groups than that in the titanium particle group (P<0.05).Levels of SOD and GSH were lower in particle groups than that in the control group (P<0.05).Levels of SOD and GSH were lower in cobalt particle , chromium particle and iron particle groups than that in the titanium particle group (P<0.05). Conclusion Oxidative stress levels increased and anti-oxidant levels decreased in mononuclear cells when cocultured with metal debris .Cobalt particles , chromium parti-cles and iron particles induced higher changes than that in titanium particles .Oxidative stress may play an important role in metal deb-ris-mediated osteolysis .

BACKGROUND: Total hip replacement in middle-aged patients is challenging regarding restoration and survival,because these patients are more active than old patients.OBJECTIVE: To retrospectively investigate whether a cementless prosthesis could restore hip function,decrease osteolysis,wear,and enhance prosthesis survival in middle-aged patients.METHODS: Clinical and radiological evaluations of patients undergoing single-side total hip replacement with cement and cementless prosthesis were analyzed preoperatively as well as at 6 months,1,4 and 7 years postoperatively.The outcomes of total hip replacement were assessed using Harris hip scores and survival rate.End point was loosening or revision of the femoral component for any reason.RESULTS AND CONCLUSION: Cementless prosthesis had gained better Harris hip scores than that of cement prosthesis group at 6 months,1,4 and 7 years postoperatively(P < 0.05).The survival rate was greater in cementless prosthesis compared with cement prosthesis during 7-year follow-up(P < 0.05).Results have suggested that cementless prosthesis achieves high rate of functional restoration and a low rate of complications in middle-aged patients following total hip replacement.

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.

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.

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.

Based on the current study of the influence of mechanical factors on cell behavior which relies heavily on experiments in vivo, a culture chamber with a large uniform strain area containing a linear motor-powered, up-to-20-Hz cell stretch loading device was developed to exert mechanical effects on cells. In this paper, using the strain uniformity as the target and the substrate thickness as the variable, the substrate bottom of the conventional incubation chamber is optimized by using finite element technique, and finally a new three-dimensional model of the incubation chamber with "M" type structure in the section is constructed, and the distribution of strain and displacement fields are detected by 3D-DIC to verify the numerical simulation results. The experimental results showed that the new cell culture chamber increased the accuracy and homogeneous area of strain loading by 49.13% to 52.45% compared with that before optimization. In addition, the morphological changes of tongue squamous carcinoma cells under the same strain and different loading times were initially studied using this novel culture chamber. In conclusion, the novel cell culture chamber constructed in this paper combines the advantages of previous techniques to deliver uniform and accurate strains for a wide range of cell mechanobiology studies.
Stress, Mechanical ; Cell Culture Techniques ; Computer Simulation ; Finite Element Analysis