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Objective To evaluate the biomechanical properties of 3D printed individualized titanium alloy pelvic prosthesis in static and gait states by the method of finite element analysis. Methods Three patients with different types of pelvic tumors were treated by hemi-pelvic arthroplasty with resection of hemi-pelvis. CT and MRI were performed before the surgery, and the corresponding individualized titanium alloy pelvic prostheses were designed. The pelvic models were reconstructed with 3D reconstruction technique, and then assembled with the individualized pelvic prostheses. The human skeletal muscle model was established by AnyBody software to perform gait dynamics analysis. The stress distribution and stress concentration areas of 3 reconstructed pelvic models in static and gait states were obtained by ABAQUS. Results Under both static and gait conditions, the maximum stress of the 3 pelvic prostheses was smaller than the yield strength of the titanium alloy. The pelvic ring of the reconstructed pelvis could meet the rule of stress conduction. The patients’ daily life returned to normal condition after the surgery. Conclusions The effect of 3D prosthetic titanium prosthesis on recovery of pelvic ring is satisfactory, and its effectiveness and stability can meet the requirement of human biomechanics. The analytic results can provide references for clinicians and prosthesis designers.
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Objective To evaluate the biomechanical properties of 3 D printed individualized titanium alloy pelvicprosthesis in static and gait states by the method of finite element analysis.Methods Three patients with different types of pelvic tumors were treated by hemi-pelvic arthroplasty with resection of hemi-pelvis.CT and MRI were performed before the surgery,and the corresponding individualized titanium alloy pelvic prostheses were designed.The pelvic models were reconstructed with 3D reconstruction technique,and then assembled with the individualized pelvic prostheses.The human skeletal muscle model was established by AnyBody software to perform gait dynamics analysis.The stress distribution and stress concentration areas of 3 reconstructed pelvic models in static and gait states were obtained by ABAQUS.Results Under both static and gait conditions,the maximum stress of the 3 pelvic prostheses was smaller than the yield strength of the titanium alloy.The pelvic ring of the reconstructed pelvis could meet the rule of stress conduction.The patients' daily life returned to normal condition after the surgery.Conclusions The effect of 3D prosthetic titanium prosthesis on recovery of pelvic ring is satisfactory,and its effectiveness and stability can meet the requirement of human biomechanics.The analytic results can provide references for clinicians and prosthesis designers.
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Objective To propose some detailed methods for diagnosis of aseptic loosening failure in clinic by studying the mechanical mechanism and the specific causes of aseptic loosening failure after the total hip arthroplasty (THA). Methods The causes of aseptic loosening were investigated from the view of biomechanics, such as strength of the bone cement layer, interface fretting, stress shielding, wear and osteolysis; the relationships between aseptic loosening failure and products, clinical and patient factors were analyzed; the method to detect loosening before the revision surgery was also studied. Results The reasoning route for aseptic loosening failure analysis after THA was proposed, and detection of aseptic loosening with fluoroscopic analysis (FSA) technique before the revision surgery was conducted successfully. Conclusions The reasoning route for aseptic loosening failure analysis can help to discover reasons of failure occurrence. Loosening can be detected and confirmed in vivo by FSA method, which can also assist the clinician for diagnosis and treatment of aseptic loosening after the THA.
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<p><b>OBJECTIVE</b>To study mtDNA, GJB2, GJB3 and determine gene mutation situs and frequency in Uighur and Han people with hereditary nonsyndromic hearing loss, and to compare the differences of gene mutation situs and frequency between Uighur and Han people.</p><p><b>METHODS</b>Blood samples were obtained from 93 patients (43 Uygur and 50 Han) with hereditary non-syndromic hearing loss and 110 normal people (56 Uygur and 54 Han). Genomic DNA was extracted from isolated leukocytes, and amplified by polymerase chain reaction (PCR). PCR products of GJB3 were sequenced directly; while PCR products of mitochondrial DNA 12S rRNA A1555G point mutations were analyzed by PCR-Alw26I digestion, and positive ones were further sequenced. GJB2 genes of 83 patients (43 Uygur and 40 Han) with hereditary non-syndromic hearing loss and 98 normal people (46 Uygur and 52 Han) were directly sequenced.</p><p><b>RESULTS</b>Among GJB3 genes of 93 patients, 2 cases of 33C-T, 2 cases of of 766G-A, 7 cases of 357C-T, and 4 cases of 798C-T were detected. Mitochondrial DNA 12SrRNA A1555G mutation was detected in 8 patients (2 Uygur and 6 Han). Nine kinds of base changes of GJB2 were detected: 109G-A, 233-235delC, 79G-A, 196G-A, 341A-G, 564G-A, 380G-A, 71G-A, and 35delG. In the control group, detected GJB3 mutations included 4 cases of 357C-T, 5 cases of 798C-T, and 2 cases of 93C-T; while 9 kinds of base changes of GJB2 were detected: 341A-G, 380G-A, 457G-A, 79-GA, 109G-A, 281A-G, 21G-T, 171G-T, and 368C-A. For mtDNA 12SrRNA A1555G, the difference between study group of and control group of Han people was statistically significant (P < 0.05). For GJB2 mutation 79G-A, the difference between study group and control group was statistically significant (P < 0.05) in both Uygur and Han people; while for GJB2 mutation 341A-G, the difference in study group between Uygur and Han people was statistically significant (P < 0.05). And for GJB3 mutation 798C-T, the difference was statistically significant both between study group and control group, and between Uygur and Han people (P < 0.05).</p><p><b>CONCLUSIONS</b>In Xinjiang, mutation rate was high for mtDNA 12SRNA A1555G. while GJB3 gene mutations were not the main cause of the hereditary nonsyndromic hearing loss. There were certain ethnic and geographical characteristics of GJB2and GJB3 mutations.</p>
Subject(s)
Adolescent , Child , Child, Preschool , Female , Humans , Young Adult , Base Sequence , Case-Control Studies , China , Epidemiology , Connexin 26 , Connexins , Genetics , DNA, Mitochondrial , Genetics , Hearing Loss , Epidemiology , Ethnology , Genetics , Mutation , Pedigree , RNA, Ribosomal , GeneticsABSTRACT
Objective To observe the effect of lnng-term in vitro culture on the biological properties of adipose-derived stem cells(ADSCs)as seeding cells of tissue engineering.Methods The surface makers and apoptosis of primary and passaged human ADSCs were identified by flow cytometric analysis.Osteogenic differentiation of ADSCs at different passages were identified by alkaline phosphatase(ALP),Von Kossa staining and RT-PCR respectively.Results The surface marker expression of mesenchymal stem cells on ADSCs was high and did not change with passages of the cells.The early apoptosis rate of the cells was 1% to 2%,and increased insignificantly from passage one to passage nine.The osteogenic potential of ADSCs confirmed by ALP,Von Kossa staining and RT-PCR was maintained to as late as passage eight.Conclusion Since the biological properties of ADSCs are stable,they can be served as optimal seeding cells for tissue engineering and regenerative research.
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Objective To investigate the ostengenie potential of adipose-derived stem cells(AD- SCs)when exposed to adenovirns containing hBMP-2 cDNA(Adv-hBMP-2)and offer a choice of cell source for gene therapy and tissue engineering.Methods Human adipose tissues were obtained from patients who received orthopaedic surgery or liposuction.ADSCs were obtained by digesting the adipose tissues.Firstly,flowcytometric analysis was performed for the confirmation of mesenchymal stem cell ori- gin and the surface markers including CD34,CD44,CD68,CD71,CD90,and CD105.The ADSCs were transfected by Adv-hBMP-2 and the effects were tested in vitro,lmmunoprecipitation and Western blotting and ELISA were performed for confirming BMP gone transduction and its stable expression.The transform of ADSCs was assessed by extracellular ALP staining,intracellular ALP spectrophotometry,von Kossa staining and RT-PCR.In the in vivo experiment ADSC-Adv-hBMP-2 cells were injected into the hind limb of nude mice and analyzed radiographically and histologically.Results ADSCs were successfully isolated from human adipose tissues.The isolated ADSCs expressed CD44,CD71,CD90 and CD105 and CD34 and CD68 were absent.The result confirmed the mesenchymal stem cell origin of the cells.West- ern blotting and ELISA confirmed successful and persistent hBMP-2 production by ADSC-Adv-hBMP-2 cells.Extracellular ALP staining,intracellular ALP spectrophotometry,yon Kossa staining and RT-PCR revealed that ADSCs treated with Adv-hBMP-2 had a tendency of transfering into osteoblast.X-ray and H&E sections from hind limb of nude mice injected with ADSC-Adv-hBMP-2 cells confirmed bone forma- tion at 2 weeks.Conclusions Liposuction aspirates contain abundant ADSCs that can be transduced with hBMP-2 gene,and the tranduced ADSCs differentiate into the osteoblast.ADSCs may be an ideal source of mesenchyme-lineage stem cells for gone therapy and tissue engineering.