1,721,088 research outputs found
The detached osteochondral fragment as a source of cells for autologous chondrocyte implantation (ACI).
No full textAutologous chondrocyte transplantation in osteochondral lesions of the ankle joint
No full textThe aim of this study was to assess the repair of osteochondral defects of the ankle joint with hyaline cartilage. For this purpose we have been using a technique of autologous chondrocyte transplantation for osteochondral defects of the talus for the last two years. Until the method described in the paper, treatment methods proposed for the repair of cartilaginous defects have not been histologically effective in restoring the hyaline cartilage sheath, and in all cases the neoformation of cartilage was of a fibrocartilaginous nature with varying cellular characteristics. Clinical and histological results obtained using this surgical technique have confirmed its validity. Furthermore, neither subjective nor objective complications have been reported. Less pain and better articular function have also been observed. According to the AOFAS score, an improvement from an average score of 32/100 points pre-op. to 91/100 points at 24 months of follow up was obtained. Laboratory data have confirmed the presence of reconstructed cartilage with chondrocytes and expression of collagen II, characteristic of hyaline cartilage
One-step bone marrow-derived cell transplantation in talar osteochondral lesions
No full textThe ideal treatment of osteochondral lesions is debatable. Although autologous chondrocyte implantation provides pain relief, the need for two operations and high costs has prompted a search for alternatives. Bone marrow-derived cells may represent the future in osteochondral repair. Using a device to concentrate bone marrow-derived cells and collagen powder or hyaluronic acid membrane as scaffolds for cell support and platelet gel, a one-step arthroscopic technique was developed for cartilage repair. We performed an in vitro preclinical study to verify the capability of bone marrow-derived cells to differentiate into chondrogenic and osteogenic lineages and to be supported onto scaffolds. In a prospective clinical study, we investigated the ability of this technique to repair talar osteochondral lesions in 48 patients. Minimum followup was 24 months (mean, 29 months; range, 24-35 months). Clinical results were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) score and the influence of scaffold type, lesion area, previous surgeries, and lesion depth was considered. MRI and histologic evaluation were performed. The AOFAS score improved from 64.4 ± 14.5 to 91.4 ± 7.7. Histologic evaluation showed regenerated tissue in various degrees of remodeling although none showed entirely hyaline cartilage. These data suggest the one-step technique is an alternative for cartilage repair, permitting improved functional scores and overcoming the drawbacks of previous techniques. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. © 2008 The Association of Bone and Joint Surgeons
Human articular chondrocytes immortalized by HPV-16 E6 and E7 genes: Maintenance of differentiated phenotype under defined culture conditions.
Full text linkObjective To establish an immortalized normal human articular chondrocyte line which could be useful for a better understanding of cell molecular mechanisms relevant for the development of new therapeutic approaches in rheumatic diseases.
Design Chondrocytes from human adult articular healthy cartilage were transfected in primary culture with a plasmid containing two human papilloma virus type 16 (HPV-16) early function genes: E6 and E7, using the highly efficient cationic liposome-mediated (lipofection) procedure. The transfection was verified by reverse transcriptase-polymerase chain reaction analysis of E7 mRNA and by immunofluorence localization of the E7 protein in the cell cytoplasm. The established chondrocyte cell line was examined in monolayer and in two culture conditions that were described to re-induce differentiated characteristics: culturing in a serum-free defined medium supplemented with an insulin-containing serum substitute and seeding on a hyaluronan-based non-woven structured biomaterial. The expression of markers characteristic of cartilage was shown in the mRNA by reverse transcriptase-polymerase chain reaction. Immunohistological staining and Western blotting analysis were performed to evaluate type II collagen synthesis. Proteoglycans deposition was detected by Alcian Blue staining. A Field Emission In Lens Scanning Microscopy was used to look at the morphology of the immortalized cells at very high magnification.
Results Normal human articular chondrocytes were efficiently transfected leading to the establishment of an immortalized cell line as confirmed by HPV-16 E7 mRNA and protein detection. These cells were able to re-express type II collagen both at mRNA and protein levels under the two defined cultured conditions we used, still maintaining type I collagen expression. Collagen IX mRNA was present only in early primary culture while collagen type X and aggrecan transcripts were always detected. Alcian Blue staining showed a proteoglycan-rich matrix production. The ultrastructural analysis of the immortalized cells revealed that their morphology strictly resembled that of normal chondrocytes.
Conclusions The cell line that we obtained may be a useful tool for increasing our knowledge of the genetic and biochemical events involved in the processes of cartilage growth and differentiation. Moreover, it appears to be a suitable model for pharmacological and toxicological studies related to rheumatic diseases relevant to humans
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Glucosamine interferes with Mitogen-Activated Protein kinase pathway by inhibiting JNK and p38 phospholitation, in human chondrocytes
No full textCathepsin B as a soluble marker to monitor the phenotypic stability of engineered cartilage.
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