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Objective@#To investigate the tissue structure, chondrocyte characteristics, and the differential expression of related genes and cell surface markers of auricular cartilage of patients in different ages, in order to provide a basis for the age selection of tissue engineered cartilage repair defects.@*Methods@#The auricular cartilage tissue was obtained from 22 patients with microtia in the Plastic Surgery Hospital, Chinese Academy of Medical Science, ranged from 6 to 28 years old, and divided into the child group (6-12 years old), the adolescent group (13-18 years old) and the adult group (21-28 years old). The proliferation and differentiation features of chondrocytes which from different-aged patients were detected. Furthermore, quantitative real-time PCR was used to detect the differences in the expression of genes related to cell proliferation and chondrocyte extracellular matrix. Flow cytometry, immunofluorescence and immunohistochemistry were used to detect the differences in the expression of mesenchymal stem cell markers CD90, CD44, CD73 and CD105 in chondrocytes. SPSS Statistics 21.0 software was used to process statistics.@*Results@#The proliferation capability of auricular chondrocytes of children was stronger than adolescents and adults, the child group vs the adult group P<0.05, the child group vs the adolescent group P<0.01. The expression of cartilage extracellular matrix related gene COL2A1 increased with age, the child group vs the adult group P<0.01, the adolescent group vs the adult group P<0.01. While the capability of cell osteogenic differentiation decreased with age(P<0.05). However, there was no significant difference in the capability of adipogenic differentiation when considering the ages of patients. The results of both flow cytometry and real-time PCR showed that the expression of mesenchymal stem cell markers decreased with age, with the most significant decrease in CD90(P<0.01).@*Conclusions@#The biological characteristics and stem cell content of cells derived from auricular cartilage tissue was influenced by the patients′age.
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BACKGROUND:Artificial lumbar disc replacement is a new choice for the treatment of degenerative disc disease, and preserves lumbar vertebra’s biomechanical characteristics during pain elimination. The design of the prosthesis structure and material needs further study and validation. OBJECTIVE:To review the structure and material types of presently designed artificial lumbar discs, then to discuss the trends in the optimization design of prosthesis. METHODS:The PubMed database, China National Knowledge Infrastructure database and Chinese BioMedical Literature Database were searched for related articles concerning artificial lumbar disc and type and biomechanics of nucleus pulposus prosthesis material published from January 2005 to February 2013 by the first author. Key words were“artificial lumbar disc, principle of prosthesis design, structure, material, clinical trials”in Chinese and“artificial lumbar disc, total disc replacement, structure, material, clinical trial”in English. Repetitive and old studies were excluded. 135 articles were found, but 36 articles were included for review. RESULTS AND CONCLUSION:At present, the materials for intervertebral discs include cobalt-chromium al oy, ceramics, stainless steel, titanium al oy and ultrahigh molecular weight polyethylene. Artificial lumbar disc is commonly made by different materials. Bryan prosthesis is most commonly used in the clinic. Three-dimensional finite element analysis, in vitro trial and clinical studies verified its good biomechanical property. The successful rate of replacement was high. Nucleus prosthesis contains prefabricated type and situ polymerization type, and obtains smal injury, so it is a hot focus in present study, but it cannot achieve biomechanical function of human nucleus pulposus. To dig novel material is a future direction for designing individual prosthesis. The prosthetic structure and biomaterial design experience constant improvement and development. This study combines latest study trend and prospects the development of biomimetic design, material improvement, the optimization design of prosthesis and assisted devices.
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BACKGROUND:Early clinical application of non-biological materials (bone cement) for treatment of hip joint is ineffective, due to the large fixed range, long fixation time, as wel as aging and rupture of bone cement interface causing complications such as prosthetic loosening. Thus, postoperative range of motion of the hip joint can be affected to some degree. OBJECTIVE:To investigate the methods and progress of biological and non-biological materials for total hip replacement and to assess the features and clinical application of different hip prostheses. METHODS:A computer-based search of PubMed and CNKI was performed by the first author to retrieve articles related to biological materials and tissue-engineered hip joint using the keywords of“carpal bone, fracture ununited”in the title and abstract. The keywords were limited to Chinese and English. RESULTS AND CONCLUSION:Biological materials for internal fixation have good wear resistance, corrosion resistance and biocompatibility. Currently, the combination of metal joint head and polyethylene acetabulum with ultrahigh molecular weight is the most commonly used in hip replacement. However, the metal joint head exhibits an elastic modulus far from the human skeleton, resulting in stress shielding effects which are easy to cause prosthetic loosening and instability. Bio-inert ceramics has high in vivo stability and good mechanical strength;and bioactive ceramics has bone conduction characteristics and performance of the living bone integration. Composite prosthesis, because of adjustable elastic modulus and sufficient mechanical strength, shows the mechanical properties close to the human bone and has been gradual y noticed. However, there is a lack of ideal prostheses with good biocompatibility and biomechanics. Therefore, hip design and manufacturing processes should be improved to elevate wear resistance and mechanical properties, to enhance the binding between prosthesis and the host bone, and to reduce stress shielding in order to improve the biocompatibility of the implant with the host, and extend the prosthetic life.