BACKGROUND:The finite element analysis method is more accurate and fast to construct the three-dimensional model of the human skeleton and design the bone surgical medical instrument.
OBJECTIVE:To establish locking plate model according to the clavicle model, analyze and evaluate stress distribution of locking plate of the finite element model under bending and torsion conditions.
METHODS:Chest scan was carried out in a healthy young adult male by adopting 64-row spiral CT and his two-dimensional image data were gotten. The obtained data were analyzed with Mimics 10.0 software to establish the three-dimensional clavicle finite element model. The clavicle locking fixation plate model was established by applying the UG software. The locking fixation plate was evaluated by utilizing the abaqus software when the plate was bent while down to give force of 200 N, and twisted while 200 N?mm, to simulate the force and analyze the stress distribution of the locking plate.
RESULTS AND CONCLUSION:Based on the original image parameters provided by CT, this experiment produced a three-dimensional model of the clavical titanium plate which fitted better to bones. This model can obtain a single individual, personalized plate by three-dimensional printing technology. The finite element analysis basical y can simulate the actual stress of the plate. For straight plate and“S”-shape plate, in lateral bending and axial torsion loads, the maximum stress distribution of the seven-hole titanium plate is located in the center of the center hole. During actual surgical procedures, clavicle fracture fragments and middle locking hole had stress superposition. If the titanium plate can avoid the stress concentration, it can effectively avoid the occurrence of the broken plate after implantation, provide theoretical guidance for clinical practice, and provide reference and technical route for biomechanical analysis of other types of titanium plate.

Adolescent ; Bone Screws ; Child ; Female ; Femoral Neck Fractures ; surgery ; Fracture Fixation, Internal ; instrumentation ; Humans ; Male

Objective To elucidate the association of the susceptibility for rheumatoid arthritis ( RA )and peptidylarginine deiminase 4(PADI4) genetic single nucleotide polymorphism (SNP) in Han population in Hebei province.Methods This hospital-based ease-control study included 105 untreated RA patients and 96 healthy controls.The genotypes and allele frequencies of padi4_92 gene polymorphisms were analyzed by PCR-RFLP method,and the analysis of linkage disequilibrium and haplotype construction were performed for padi4_92,padi4_94 and padi4_104 SNPs.The Peason Chi-square test and Woolf statistic method were used to analyze the odds ration (OR) and 95％ confidence interval (95％CI).Results Significant differences in the frequency of PADI4 alleles and genotypes between the cases and controls were observed.The combined effect of padi4_92,padi4_94 and padi4_104 SNPs was analyzed by SHEsis snd Genehunter software,and got three haplotypes,CCC,GTT and GCC.There was significant difference in haplotypes distribution of 3 SNPs of padi4 between the two groups.This analysis of haplotypes revealed that haplotype of PADI4 was a risk factor for RA The ORs for these three haplotypes for RA susceptibility were 0.634 (95％CI=0.425-0.946),1.306 (95％CI=0.864-1.975),4.286 (95％CI=1.274-14.424),respectively.Conclnsion The SNPs of PADI4 may contribute to genetic susceptibility to RA in Han population in Hebei Province.

Background Many eye diseases such as central retinal artery occlusion,glaucoma and ischemic optic neuropathy,etc.lead to retinal ischemia-reperfusion injury (RIRI) and furthmore visual functional damage.It is neeessary to study the treatment of RIRI.Objective This study was to observe and discuss the influence of aminoguanidine on the retina morphological changes and its mechanism after RIRI.Methods Eighty clean healthy male Japanese white rabbits were randomly divided into normal injury group,RIRI group and aminoguanidine (AG)treated group.The model of RIRI was established by infusing saline solution into the anterior chamber to elevate intraocular pressure (IOP) in both RIRI group and AG group.AG was intraperitoneally injected in the models of the AG group,and normal saline solution was used at the same method in tbe normal group and the RIRI group.The fundus photography and fundus fluorescein angiography(FFA) were pertormed on the rabbits at the moment of retina ischemia and 6,24 and 72 hours after reperfusion.The parts of rabbits were sacrificed 1,6,24 and 72 hours after reperfusion,followed by the enucleation of the eyeballs.Retinal section was prepared for TUNEL examination to evaluate the apoptosis of retinal cells.Nitric oxide (NO) concentration in retina was detected with nitrate reductase,and the activity of inducible nitric oxide synthase (iNOS) was measured by colorimetric detection.The use of the animals followed the Regulations for the Administration of Affairs Concerning Experimental Animals by State Science and Technology Commission.Results The fundus photography and FFA showed that the retinal edema was more mild,and the percentage of vascular occlusion was lower in the AG treatment group than that in RIRI group and the amount and area of fluorescein leakage were also smaller than the treatment group.The numbers of TUNEL positive cells in the AG treatment group were less than those in the RIRI model group at 1,6,24 and 72 hours after experiment (F分组 =2762.37,P =0.00 ; F时间 =894.24,P =0.00).Numbers of TUNEL positive cells between adjacent time points were significantly different in both RIRI model group and AG treatment group (RIRI group:q =24.475,36.591,-20.37,P＜0.05;AG group:q =20.94,16.79,-6.92,P＜0.05),with the peak value at 24 hours after experiment.NO contents were significantly higher in the RIRI model group compared to AG group at various time points(q =3.84,4.01,8.91,3.75,P＜0.05),and those between adjacent time points showed significant differences (RIRI group:q=4.77,13.403,-10.29,P＜0.05;AG group:q=4.55,9.05,-5.08,P＜0.05).iNOS activity was significantly elevated in the RIRI model group compared with AG group(q=-3.74,-4.94,-6.53,-3.98,P＜0.05),and obvious differences also were seen between the adjacent time points in both two groups(RIRI group:q =8.43,6.71,-6.39,P＜0.05 ;AG group:q =4.16,5.08,-3.93,P＜0.05).Conclusions Aminoguanidine can protect the retinal function and morpbology from oxidative stress damage after RIRI by reducing the NO level and inhibiting the iNOS activity in retina.

AIM:TostudythefunctionofmicroRNA(miR)-19aandmiR-92abyseed-targetinginhibitionin multiple myeloma cells and their signal pathways .METHODS:The experiments were divided into t-antimiR-19a group, t-antimiR-92a group, scramble control group and blank control group .The growth-inhibitory potencies were measured by MTT assay.The ability of cell colony formation was measured by cell colony formation assay .The ability of cell invasion was measured by Transwell experiment .The miR-19a and miR-92a target gene signal pathways were integrated by miRFo-cus software.RESULTS:MTT assay showed that t-antimiR-19a and t-antimiR-92a significantly inhibited the viability of multiple myeloma cells , and the best concentration and time were 0.5μmol/L and 48 h, respectively .The colony number in t-antimiR-19a/92a group was less than that in scramble control group .The transfection with t-antimiR-19a or t-antimiR-92a effectively decreased the cell invasion , as the relative invasion cell number was significantly decreased compared with scramble control group.miR-19a and miR-92a were involved in mTOR signaling, cell cycle and other cancer pathways . CONCLUSION:miR-19a and miR-92a cluster might be a potential target for therapeutic intervention in multiple myelo-ma.

Objective Imatinib mesylate (IM) is the most active agent in treating chronic myeloid leukemia (CML). 5-Aza-2-deoxycytidine (DAC) is a cytosine analogue that inhibits DNA methylation and the activity in myeloid leukemia. Therefore,we investigated combining these two drugs in human leukemia cell line K562. Methods The effects of IM and DAC was examined in K562 cells including cell viability using MTT method,cell cycle phase and cell death using flow cytometric (FCM),and the expression of bcr-abl mRNA by RT-PCR. Results Both DAC and IM resulted in time and concentration-dependent induction of cell death. DAC and IM in combination produced a greater inhibition of growth against K562 cells (F =43.947,165.580,321.193,296.101,P<0.05). The main effect and interaction between two drugs was statistically significant (F = 202.759,168.457,417.538,P <0.001) after 24 h,48 h,72 h and a greater reduction in expression of bcr-abl mRNA than either agent alone. The difference was statistically significant (F =71.981,P <0.05). The number of G1 phase cells were increased significantly when induced by single agent. 48 h incubation with IM 0.2 μmol/L alone or combined with DAC 4 μmol/L showed 6.7 %,8.4 % pre-apoptosis cells,respectively. After incubation for 48 h with DAC 4 μmol/L,the expression of mRNA were decreased by 14 %,IM 0.2 μmol/L showed 40 % reduction,and combination group were significantly depressed for the mRNA expression by 60 %. Conclusion The combination of DAC and IM showed synergistic effects on cell death in K562 cells. These data suggested that DAC used in combination with IM has clinical potential in the treatment of chronic myeloid leukemia.

Purpose To evaluate the expression of miR-21 in the tissues and cell lines of hepatocellular carcinoma,and to try to find its possible target genes.Methods The expression profile of miR-21 was detected in hepatocellular carcinoma tissues and cell lines.Mter miR-21 inhibitor was used,the alterations in the vitality and invasion of hepatocellular carcinoma cells were observed.The possible target gene of miR-21 was predicted by bioinformatics analysis.The influence of miR-21 inhibitors on the target gene activity was evaluated by dual luciferase reporting gene system.Results The expression level of miR-21 was significantly higher in hepatocellular carcinoma tissues than that in the adjacent ones (P ＜0.05).The expression level of miR-21 in hepatocellular carcinoma cells was significantly higher than that in the hepatic cells (P ＜0.01).After inhibiting miR-21,the viability and invasion ability of hepatocellular carcinoma cells were decreased (P ＜ 0.01).The expression level of programmed cell death 4 (PDCD4) in hepatocellular carcinoma tissues was significantly lower than that in the adjacent tissues (P ＜ 0.01).Its expression level in hepatocellular carcinoma cells was significantly lower than that in the hepatic cells (P ＜ 0.01).After interfering with PDCD4,the vitality and invasion ability of liver cancer cells were increased (P ＜ 0.05).Dual luciferase reporter gene assay indicated that by inhibiting miR-21,the expression level of PDCD4 was up-regulated (P ＜ 0.01).The vitality and invasion ability of liver cancer cells were reduced (P ＜ 0.001).Conclusion MiR-21 can regulate the growth and invasion of liver cancer cells through targeting PDCD4.

Objective To study the effects of Hydergine on expression of N-methyl-D-aspartate receptors in hippocampus and actions of mice with ischemia-reperfusion injury.Methods 36 mice were randomly divided into model group,Hydergine group and sham-operated group. The models of ischemia-reperfusion injury were made by knotting bilateral common carotid arteries. The behavioral abnormalities were investigated by step-down test and water maze test, and the expressions of N-methyl-D-aspartate receptors in neurons of hippocampus were observed by immunohistochemistry technique. Results Compared with model group, the performance records of learning and memory in Hydergine group were better (all P

ObjectiveTo evaluate the enteral nutritional schemes for patients with acute cerebral infarction in effectiveness and economy. Methods117 acute cerebral infarction patients with dysphagia were divided into 3 groups. Homogenized diet, sequential intestinal nutrition and intestinal integral protein were provided respectively for these groups by nasogastric tube feeding. The clinical effectiveness was evaluated and the cost-effectiveness analysis was done pharmacoeconomically 14 d later. ResultsThe effective rates of these schemes were 42.5%, 75% and 49%, while the cost-effectiveness ratios were 9.84, 29.37, 42.16 respectively. ConclusionFor the acute cerebral infarction patients with dysphagia, the scheme of sequential intestinal nutrition is most effective, and the homogenize diet is most economical.

Objective To investigate the clinical, electromyographic and cervical magnetic resonance imaging (MRI) characteristics of Hirayama disease. Methods Fifteen patients with Hirayama disease were observed for special clinical manifestations and underwent electromyographic examination of the bilateral distal upper limb muscles and peripheral nerve conduction velocity. MRI of the neck in neutral and fully flexed positions was performed to identify potential lower cervical cord atrophy and cervical curvature anomalies. Results All the 15 male patients had disease onset during puberty with asymmetric muscular atrophy and weakness of the hands and forearms. Concentric needle electromyography revealed prolonged duration and large amplitude of the motor unit potentials in the compromised distal limb muscles with also increased polyphasic potentials and poor recruitment, involving mainly the C7, C8 and T1 myotomes. In neutral neck position, MRI identified lower cervical cord atrophy in 9 patients, occurring mainly at C5, C6 levels;in fully flexed position, all patients showed forward displacement and flattening of the lower cervical cord, occurring mostly at C6 level. Conclusion Hirayama disease occurs mainly in puberty in young male patients, whose clinical features and electromyographic examination often indicate localized anterior horn anomalies in the lower cervical cord. MRI of the neck in neutral and fully flexed position can provide valuable assistance in the diagnosis of this disease.