BACKGROUND:At present,there are many established femoral finite element studies,but previous studies focused on femoral biomechanics of the outside are few.OBJECTIVE:To establish three-dimensional finite element model of structure of the proximal femur,and to analyze its biomechanics in normal standing position to provide reasonable evidence for clinical application.DESIGN,TIME AND SETTING:A three-dimensional finite element model analysis was performed in General Hospital of Tianjin Medical University from December 2008 to April 2009.PARTICIPANTS:One male volunteer aged 30 years was enrolled at General Hospital of Tianjin Medical University.Femur lesion or injury was excluded by means of X-ray.METHODS:The primitive femur CT data were adopted according to Dicom 3.0 standard in Mimics so as to obtain the primitive three-dimensional femur model which was established via threshold defining,region enlarging and morphological performing.The primitive model was remeshed and combined with ANSYS software to create a final finite-element model.The model obtained by using the Mimics was loaded with 200 N vertical loading to check out the difference of the stress distribution.MAIN OUTCOME MEASURES:Using 200 N as the external load in the vertical direction,the Vonmises stress distribution of the femur was detected.RESULTS:The applications of Mimics and Ansys software could create a finite element model of proximal femur.It was found that the correspondent relationship between stress and structure in proximal femur was verified.CONCLUSION:Mimics can build more three-dimensional finite element models in line with the proximal femoral mechanical structure and mechanical properties.The mechanical properties of the femur are more credible,and the results of the analysis support the clinical application of the guidance.

Objective To research the effect of GGCX gene on MMP13 in rabbit osteoarthritis cartilage cells and investigate its effect on osteoarthritis cartilage degeneration.Methods Six Japanese big ear rabbits weighted (2.0±0.2)kg were randomly di vided into three groups,each group seted a rabbit as control.Anterior cruciate ligament transection method was used to build osteoarthritis cartilage degeneration model at second,forth,sixth week.Articular cartilage was separated successfully after the model were built,cartilage cells were divided from articular cartilage and cultured in 6-well cell culture plate.Cartilage cells were divided into blank group,negative control group and transfection group.PCR method and Western blot were conducted to detect GGCX and MMP13 expressed at the level of mRNA and protein.Results Compare with blank group and negative control group,the expressin level of GGCX incresed,while the MMP13 expression level dcresed(P＜0.05).Conclusion Over expression of GGCX gene can ob viously decrease the expression of MMP13,it provide experimental basis for osteoarthritis of the in vitro gene therapy.

A total of 68 patients with histologically proven endometrial cancer were preoperatively evaluated with a 3.0 T magnetic resonance (MR) unit.Two radiologists interpreted the depth of myometrial invasion on T2-weighted and diffusion-weighted(DW) MR (b =700 s/mm2) imaging.Myometrial tumor spread was classified as superficial (＜ 50％) or deep (≥50％ myometrial thickness).Statistical methods included Kappa statistics for reader agreement,accuracy assessment and receiver operating characteristic analysis for diagnostic performance comparison.For assessing the depth of myometrial invasion,the diagnostic accuracy,sensitivity and specificity were as follows:T2-weighted imaging-reader 1st,61.8％,60.0％ and 65.2％;reader 2nd,66.2％,64.4％ and 69.6％ ; T2-weighted combined DW imaging-reader 1st,86.8％,84.4％and 91.3％ ; reader 2nd,89.7％,86.7％ and 95.7％.Reader agreement was excellent for T2-weighted combined DW imaging (Kappa =0.818).For assessing deep myometrial involvement,ROC analysis showed that the diagnostic accuracy was significantly higher on T2-weighted combined DW imaging than that on T2-weighted imaging.The AUC (area under the curve) values measured by two readers on T2-weighted and T2-weighted combined DW imagings were 0.626,0.879 and 0.670,0.912 respectively.The addition of 3.0T MR diffusion-weighted to T2-weighted imaging can improve the diagnostic performance of MR imaging in the assessment of myometrial invasion.

ObjectiveTo investigate the proliferation of rat's osteoblasts promoted by mechanical strain via the protein kinases C ξ(PKCξ) protein path-way.MethodsOsteoblasts were retrieved from SD rats' skulls in the sterilized environment.BioDynamic testing instrument was used to exert 2％ and 0％ mechanical strain on rats' osteoblasts for 180 min on the each group(2％ mechanical strain was experimental group and 0％ mechanical strain was control group); and the same method was applied on the rats' osteoblasts which pretreated with the classical PKC ξ inhibitor with 2％ mechanical strain (inhibitor group).The cell cycles of rats' osteoblasts were measured by flow cytometry; and Western blotting and immunofluorescence were used to detect expression of protein PKC ξ and phosphorylationed PKC ξ in the rats' osteoblasts.ResultsThe mechanical strain obviously increased the ratio of S period in the cell cycles.Compared to the control group and inhibitor group,a significant increase of the expression of protein PKC ξ and phosphorylationed PKC ξ in the osteoblasts was detected in the mechanical strain experimental group.ConclusionPKCξ can respond to the stimulus of the mechanical strain,which promotes the proliferation of osteoblasts through PKCξ pathway.And it plays an important role in the process of signal conduction.

ObjectiveTo measure the displacement parameters of the femoral head in space through CT three-dimensional reconstruction so as to re-understand impacted femoral neck fractures.MethodsFifty patients with impacted femoral neck fractures were included in the study.There were 17 males and 33 females.Bilateral proximal femurs of each patient were scanned by spiral CT preoperatively.Then these primitive CT data were reconstructed by Mimics 10.01 software.Registered the normal femur and fracture mirror model,the registered mirror model was generated a new mask in the CT cross-sectional images,marked key points in the masks and measured the displacement parameters of femoral head with three-dimensional measurement technology.ResultsIn the impacted femoral neck fractures,the femoral head displacement angle was 17.17°±10.40°,70％(35/50) of the patients had femoral head rotation angle was at 10° to 35°,and 30％(15/50) of the patients had femoral head space displacement more than 20°.The average displacement distance of femoral head center and the deepest point of fovea capitis were(6.49±3.60) mm and(10.42±5.92) mm,respectively.A high proportion of the impacted femoral neck fractures had a large of displacement in the three-dimensional space.It is not scientific to equal impacted femoral neck fractures to undisplaced fractures.ConclusionThree-dimensional reconstruction and digital measurement is a precise,efficient and convenient method for the measurement of femoral head displacement parameters in femoral neck fracture patients.The classic Garden classification for impacted femoral neck fractures has certain defects and limitations.Clinicians should re-understand impacted femoral neck fractures and choose more reasonable treatment.

AIM To study the effects of polydatin on free radical induced rat cortex mitochondria injury. METHODS Fe 2++VitC system was used to produce ?OH. The mitochondria was isolated. Mitochondria membrane fluidity, swelling and contents of phospholipid were determined to measure the function of mitochondria membrane. The activities of ATPase and Cytochrome C oxidase were determined to measure the ability of mitochondria energy metabolism. The activity of superoxide dismutase (SOD) and content of malondial dehyde (MDA) were determined to measure the ability of anti oxygenation. RESULTS ?OH resulted in severe neuronal mitochondria injuries and the injuries and the injuries was alleviated by Polydatin (content of 100,200,400 mg?L -1). The swelling of mitochondria was ameliorated, the decomposability of mitochondrion membrane phospholipid was decreased, the membrane fluidity of mitochondria was increased. Polydatin also significantly inhibited the decrease in SOD, Cytochrome C oxidase and ATPase activity and the increase in MDA levels caused by free radical. CONCLUSION Polydatin has a protective action against the rat neuronal mitochondria injuries induced by oxygen free radical. The mechanisms may be derived from scavenging free radicals, reducing lipid peroxides, and improving the energy metabolism.

Objective To build a three-dimension finite-element model of patella and to make a preliminary mechanics analysis on the model.Methods According to the model-building principle of Ansys software which started from point to line to area to volume,a three-dimension finite-element patella model was reconstructed on the basis of the images of spiral CT.Then,loading on the model patella were simulated and the stress magnitude and distribution on the patella were analyzed.Results Finite element analysis of the patella showed that stress concentration zone located in the middle and lower patella,indicating that fracturepredilectionsitesinthelower patellar.TheVon misesstresson thetensionsidewas significantly greater than that on pressure side.Conclusion The established finite element model of the patella can reflect the real geometry of patella treated in clinics.

Objective To investigate the isokinetic strength of knee extensors and flexors in patients with knee osteoarthritis (KOA), and to establish the correlation between the isokinetic strength and function in patients with KOA. Methods 23 patients with bilateral KOA and 14 matched normal controls finished the isokinetic test of knee extensors and flexors, the Five Times Sit-to-Stand Test (FTSST), Gait analysis, and Balance test. The KOA patients were evaluated with Visual Analog Scale (VAS) for pain and Western Ontario and McMaster University Osteoarthritis Index (WOMAC). Results It was less of the peak torque, average peak torque, average power, max rep total work, total work of knee extensors and flexors in the mainly involved limbs than the contralateral limbs (P<0.05), and more of the hamstring/quadriceps peak torque (H/Q) percentage (P<0.05) in the patients. It was less of all the observed indicators of knee extensors and average power of knee flexors in the patients than in the normal controls (P<0.05), and was more of the H/Q percentage (P<0.05). The peak torque of knee extensors correlated with the results of FTSST, walking speed, walking distance, falling index, VAS, and WOMAC-pain (P<0.05), but the peak torque of knee flexors did not (P>0.05). Conclusion It is weak of the isokinetic strength of knee extensors and flexors in patients with KOA in the mainly involved limb, as well as the isokinetic strength of knee extensors compared with the normal controls. The changes in the extensors and flexors are not equivalent. The peak torque of knee extensors significantly correlated with the pain and functions of the knee.

OBJECTIVE:To optimize the ultrasonic extraction technology for Tianshu capsules. METHODS:Using the transfer rate of active ingredient ferulic acid in Ligusticum chuanxiong and gastrodin in Gastrodia elata of Tianshu capsules as investigation indexes,L9(34)orthogonal design test was adopted to investigate the effects of ethanol volume fraction,ethanol amount,extraction time and ultrasonic power on the extraction rate. Ultrasonic extraction technology for Tianshu capsules was optimized,and verifica-tion test was carried out. RESULTS:The optimized extraction technology for Tianshu capsules was as follow as 8-fold 70% etha-nol,extracting twice under 350 W,extracting 1.5 h every time. Results of verification test showed the average transfer rate was 94.06% for ferulic acid(RSD=0.18%,n=3)and 95.02% for gastrodin(0.47%,n=3). CONCLUSIONS:The optimized tech-nology is rapid,simple,stable and feasible,and can be used for extracting the active ingredients in Tianshu capsules.

Objective To compare the biomechanical properties of Gamma3 and InterTan nails in the fixation of femoral intertrochanteric fractures. Methods Twelve synthetic femora of 4th generation were randomized into 4 equal groups ( n=3 ) for assessment of the 2 constructs of fracture fixation ( Gamma3 versus InterTan nails ) . Groups A and B were made into models of stable femoral intertrochanteric fracture (AO/OTA type 31-A1. 1) and groups C and D into unstable ones(AO/OTA type 31-A2. 3) . The biomechanical properties of Gamma3 and InterTan nails in the 4 models were tested and compared. Results For stable fracture models, the fracture gap movement increased with the increasing axial load and the torque increased with the increasing torsion angle. There were significant differences between groups A and B in fracture gap movement and torque ( P <0. 05 ) . There was no significant difference between groups A and B in failure load ( 5, 855. 5 ± 627. 8 N versus 5, 547. 1 ± 365. 4 N ) ( P > 0. 05 ) . For unstable fracture models, there were no significant differences between groups C and D in fracture gap movement when the axial loads were 500 N, 600 N or 700 N ( P > 0. 05 ) , but there was a significant difference between the 2 groups when the axial load was larger than 800 N ( P <0. 05 ) . With the increasing torsion angle, the torque increased in groups C and D. There was a significant difference between the 2 groups in the torque at the same torsion angle ( P <0. 05 ) . There were a significant difference between groups C and D in failure load ( 2, 781. 5 ± 600. 6 N versus 3, 150. 5 ± 633. 8 N ) ( P=0. 007 ) . Conclusions For stable femoral intertrochanteric fractures, InterTan and Gamma3 nails may exhibit similar biomechanical properties. For unstable femoral intertrochanteric fractures, InterTan nails may provide obviously better biomechanical stability than Gamma3 nails.