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Objective To synthesize and characterize four acryl acetyl glucosamine (DA-NAG), and to determine its biocompatibility and cell membrane binding properties, so as to provide basis for its application in medical self agglutination gels. Methods DA-NAG was synthesized by esterification reaction. The products were characterized by mass spectrometry and hydrogen spectrum. Cytotoxicity test and subcutaneous implantation test were performed on the synthesized DA-NAG. The binding properties of DA-NAG to mouse fibroblast L929 cell membrane were detected using high performance liquid chromatography (HPLC). Results The characterization of mass spectrum and hydrogen spectrum are consistent with the characteristics of DA-NAG. The product has no cytotoxicity, and the subcutaneous implantation shows that the DA-NAG can be degraded at 4 weeks without obvious stimulation to the surrounding tissues. The result of HPLC shows the binding effect between the DA-NAG and cell membrane. Conclusions DA-NAG is successfully synthesized, and it has good cytocompatibility and binding ability to cell membrane.
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Objective To introduce a self-developed computer-assisted design/rapid prototyping and guidance system used for precise placement of the acetabular component in total hip arthroplasty.Methods We collected the preoperative pelvic CT scanning data of 10 hips with aeetabular dysplasia that had undergone primary total hip arthroplasty from January 2016 to January 2017.The total time for import of radiographic images,model reconstruction,model segmentation,acetabular component position design and STL model export was calculated and compared between our self-designed software and Mimics vl 7.0.Three kinds of STL model from each case were imported into our self-developed 3D printing device,Stratasys Objet30 and Stratasys Demension SST1200es respectively for rapid prototyping.The printing efficiency and accuracy were compared among the 3 printers.The accuracy of placing acetabular component with guidance system was evaluated.Results The average time forpreoperative planningwas7.7±1.3 minbyourself-designedsoftware and 52.5 ± 15.9 min by Mimics v17.0,showing a significant difference (P ＜ 0.001).In morphological point-based comparison for each case,the 3D models exported by the 2 different kinds of software showed an average difference of 0.072 1 ± 0.069 1 mm.The average durations for rapid prototyping by the 3 different printers were 5.3 ± 0.6 h,10.8 ± 0.5 h,and 9.3 ± 0.6 h,respectively,showing significant differences (P ＜ 0.001).The guidance system resulted in precise placement.The locations of the acetabular component achieved by guide-assisted placement were not significantly different from the target ones (P ＞ 0.05).Conelusion Our self-developed preoperative planning software,rapid prototyping device and guidance apparatus for acetabular component placement may lead to good accuracy and high efficiency.
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BACKGROUND:Previous studies have indicated that resistin stimulates a large set of chemokines in chondrocytes that are known to be important in inflammatory joint lesions. OBJECTIVE:To further investigate the mechanism of co-regulation roles of transcription and post-transcription in the up-regulation of two chemokine genes CCL3 and CCL4 in chondrocytes in response to resistin. METHODS:Human chondrocytes, T/C-28a2 and ATDC5 cels were cultured. The function of resistin on the chemokine genes, and the expression of C/EBPβ, nuclear factor-κB isoforms and chondrogenic specific miRNAs were tested by qPCR. The co-regulation of C/EBPβ and nuclear factor-κB was investigated by nuclear factor-κB inhibitor (IKK-NBD) and C/EBPβ inhibitor (SB303580) treatments, and subcelular localization was detected with or without resistin stimulation. RESULTS AND CONCLUSION:Resistin could increase the expression of chemokine genes independently. Chondrocytes reacted in a non-restrictedly cel-specific manner to resistin; C/EBPβ inhibitor, nuclear factor-κB and some chondrogenic specific miRNAs in a combinatorial manner regulated chemokine gene expression. The activity of C/EBPβ was augmented by a transient increase in activity of nuclear factor-κB, and both transcription factors acted independently on the chemokine genes, CCL3 and CCL4.
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BACKGROUND:The molecular mechanism of periprosthesis osteolysis is not yet completely clear. Periprosthetic osteolysis and absorption is the pathological and physiological process typical of artificial joint loosening. Interleukin-1 can affect bone resorption process through a mitogen-activated protein kinases (MAPK) signaling pathway. OBJECTIVE:To explore the effects of siRNA-induced interleukin-1 receptor-associated kinase-4 gene (IRAK-4) silence on MAPK expression in MG63 cells, which may provide experimental basis for treatment and prevention of periprosthesis osteolysis. METHODS:The siRNA sequences of the target gene, IRAK-4, were constructed and transferred into MG63 cells using Lipofectamine 2000. There were three groups:blank group=MG63 cells, control group=MG63 cells transfected with scrambled IRAK-4siRNA, and silence group=MG63 cells transfected with specific IRAK-4 siRNA. The protein level of extracellular regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinases (p38MAPK) were detected by western blot assay. RESULTS AND CONCLUSION:The expression of IRAK-4 mRNA and protein in the silence group was significantly decreased compared with the control group. Compared with the blank and control groups, 48 hours after the transfection, IRAK-4 gene silencing in MG63 cells decreased protein expression of p-JNK1/2P46, p-ERK1/2 and p-p38MAPK (P<0.05). IRAK-4 silencing inhibited ERK, JNK and p38MAPK expression in osteoblast-like cells.
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BACKGROUND: Acetabular cup orientation using a standard radiograph of the pelvis is quite common method to assess artificial hip replacement nowadays. Non-standardization of pelvic orientation affected accuracy of measurement results, and it is difficult to compare. OBJECTIVE: To make sure how pelvis tilting affect the anteveration of the cup and to elevate clinical accuracy and compare study comparability. METHODS: Designed a simulated acetabular cup with serial concentric circles which pass through the same polars and represent anteveration of 0°, 10°, 20°, 30°, 40°, Loaded the simulated acetabular cup at an inclination of 35°, 40°, 45°, 50°, 55° to6 cadaver pelves, Made the pelves tilt around the frontal axis and sagittal axis with 5° each time in a scope of+30°. Takestandard radiograph of the pelvis accordingly. Radiograph was photographed end frontal angle of dip was measured. RESULTS AND CONCLUSION: Pelvic tilt of about 1° causes measuring errors of anteveration 0. 61 °-0. 73°. The anteveration decreased at both acetabular cups when pelvic posterior tilt and at the acetabular cup that near the X-ray source as pelvic lateral tilt. The anteveration rose at both acetabular cups when pelvic anterior tilt and at the acetabular cup that away from the X-ray source as pelvic lateral tilt. During clinical evaluation, pelvic orientation effects on measurement results should be considered.
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Objective To observe the effect of arthroscopic meniscectomy for symptomatic discoid lateral meniscus and the importance of early treatment. Methods Arthroscopic meniscectomy was performed on 29 patients (31 knees) with symptomatic discoid lateral meniscus. Partial meniscectomy was performed on 27 knees, subtotal meniscectomy on 4 knees with tear on the edge of meniscus. Results The operations on all 31 knees were successful without complications. The mean Lysholm score was 95.6 (87-100) during the follow-up, which was significantly higher than that before the operation (65.7, range 36-78; P