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OBJECTIVE@#To study the effect of dexmedetomidine (Dex) on cognitive dysfunction induced by tibial fracture in rats.@*METHODS@#Sixteen male SD rats were randomized into control group and tibial fracture group, and the behavior indicators were measured on days 1, 3, 5 and 7 after tibial fracture and the expressions of CX3L1 protein and mRNA in the hippocampus were detected. Another 24 male SD rats were randomly divided into control group, tibial fracture group, and tibia fracture with CX3CL1 antibody group, and the behavior indicators and hippocampal CX3L1 protein expression were evaluated after corresponding treatments. In another experiment, we randomized 24 male SD rats into control group, tibial fracture group and tibial fracture with Dex treatment, and tested their hippocampal CX3L1 protein and mRNA expressions as well as the behavior indicators after the treatments.@*RESULTS@#Compared with the control rats, the rats with tibial fracture spent significantly less time in the novel arm on days 1, 3, 5 and 7 after the fracture ( < 0.05) with obviously lowered expressions of CX3L1 protein and mRNA in the hippocampus ( < 0.05). In the rats with tibial fracture, treatment with CX3CL1 antibody further decreased the time spent in the novel arm ( < 0.05) and the expression level of CX3L1 protein in the hippocampus ( < 0.05); In contrast, treatment with Dex significantly increased the time spent time in the novel arm ( < 0.05) and enhanced the hippocampal expressions of CX3L1 protein and mRNA in rats with tibial fractures ( < 0.05).@*CONCLUSIONS@#Dex can alleviate cognitive dysfunction induced by tibial fracture in rats by increasing the expression of CX3CL1 in the hippocampus.
Subject(s)
Animals , Male , Rats , Cognitive Dysfunction , Dexmedetomidine , Hippocampus , Rats, Sprague-Dawley , Tibial FracturesABSTRACT
Objective Few studies are reported on the construction of a finite element model of human complex knee joint using multimodality CT and MRI images.In this study, we developed a finite element model of the knee joint for total knee arthroplasty (TKA) using matched and fused CT and MRI data, hoping to provide a useful tool for the simulation study of knee joint biomechanics of TKA.Methods The CT and MRI image data about an intact knee of a 26-year-old male volunteer were imported into the Mimics software for the establishment of 3D models of bony and soft-tissue structures.A complete knee model was developed following the registration and fusion of the constructed 3D models based on the external landmarks.After the simulated implantation of TKA components, a finite element model of the TKA knee was constructed with the Hypermesh software.Then the finite element model was analyzed following the definition of its material behavior, boundary conditions and loading.Results The finite element model of the TKA knee, which was composed of bones, ligaments, components, polyethylene insert and bone cement, was developed from CT-MRI image registration and fusion and maintained its important spatial relationship among different structures in the TKA knee.The results obtained from the finite element analysis showed the characteristics of stress distribution in the TKA knee.Conclusion The finite element model of the knee joint for TKA can be established by matching and fusing CT and MRI image data, which can be employed as a useful tool for the study of knee joint biomechanics of TKA.
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Objective To evaluate the accuracy of ultrasound-measured inferior vena cava (IVC) diameter in assessment of the preoperative blood volume in elderly patients.Methods Sixty patients,aged 60-75 yr,with body mass index 20-25 kg/m2,of ASA physical status Ⅰ-Ⅲ,scheduled for elective transurethral resection of prostate,were randomly divided into 3 groups (n =20 each):control group (group C),lactated Ringer's solution group (group RL),and hydroxyethyl starch group (group H).Lactated Ringer's solution 8 ml/kg was infused intravenously in group RL.Hydroxyethyl starch 130/0.4 8 ml/kg was infused intravenously in group H.SpO2,mean arterial pressure (MAP),HR and central venous pressure (CVP) were monitored before and after fluid therapy.The IVC diameters,both during expiration (IVCe) and inspiration (IVCi),were measured using ultrasound.IVC collapsibility index (IVC-CI) was calculated.Results The IVCeand IVCi were significantly increased,and IVC-CI was decreased after fluid therapy as compared with those before fluid therapy in RL and H groups.Compared with group C,the IVCe and IVCi were significantly increased,and IVC-CI was decreased after fluid therapy in RL and H groups.IVCe and IVCi were positively correlatedwith CVP (r=0.746 and 0.697,respectively).IVC-CI was negatively correlated with CVP (r =-0.547).Conclusion Ultrasoundmeasured IVC diameter provides better accuracy in assessing the preoperative blood volume in elderly patients.