ABSTRACT
PURPOSE: To investigate the effect of fibronectin (FN) and/or RGDS tetrapeptide on osteoblastic proliferation and osteopontin expression. MATERIALS AND METHODS: Osteoblasts were cultured on tissue culture polystyrene (TCPS) and apatite-wallastonite glass ceramics (AW-GC) with or without FN and RGDS synthetic tetrapeptide. Osteoblastic proliferation and differentiation were measured after cultivation, by determining the number of attached cells, by [3H]-thymidine assay, and by measuring the activity of alkaline phosphatase. The expression of osteopontin (OPN) was determined by RT-PCR and western blotting. RESULTS: Cellular proliferation was more increased by FN than the other variables examined (P<0.03). OPN mRNA expression by RT-PCR was induced two-fold, 24-hour after FN treatment (P<0.05). The expression of OPN by western blotting showed a five-fold increase in cells treated with FN compared with the controls. The synthetic RGDS peptides partially blocked the growth of cells induced by FN (P<0.05). RGDS tetrapeptide alone increased the OPN expression induced by cultured osteoblasts (P<0.05). CONCLUSION: FN enhanced osteoblastic proliferation on glass ceramics and induced OPN expression. Integrin occupancy by RGD-containing molecules may play a role in the process of osteoblastic proliferation rather than in osteoblastic differentiation.
Subject(s)
Animals , Rats , Alkaline Phosphatase , Blotting, Western , Cell Proliferation , Ceramics , Fibronectins , Glass , Osteoblasts , Osteopontin , Peptides , Polystyrenes , RNA, MessengerABSTRACT
PURPOSE: To determine the viability of human chondrocytes within refrigerated articular cartilage stored under conditions currently used clinically. MATERIALS AND METHODS: Osteochondral sections of human ankle taluses were stored at 4 degrees C in DMEM media for 1 to 42 days. Articular cartilage was harvested and evaluated for histologic changes and proteoglycan synthesis. RESULTS: By day 7, markedly decreased proteoglycan synthesis was observed. After 21 days, synthetic activity was virtually undetectable. Histologic specimens demonstrated chondrocyte death of a half of the cells from the superficial layer at day 7. Within 21 days, significant chondrocyte death was seen. CONCLUSION: These results suggest that proteoglycan synthetic activity and chondrocyte viability are markedly decreased in articular cartilage after cold storage for longer than 7 days.
Subject(s)
Humans , Ankle , Cartilage, Articular , Chondrocytes , Proteoglycans , Refrigeration , TalusABSTRACT
We experienced a very rare case of parosteal lipoma, which was situated on the adjacent periosteum of the tibia with hyperostosis, as a bony reaction without due causes and mimicking parosteal osteosarcoma or osteochondroma in a 30 year old Korean housewife. The hyperostosis was limited on the cortex with no connection to the medullary canal. We reported the case because of it's rarity, and its specific magnetic resonance image findings. No local recurrence was observed in 14 months after marginal excision.