The Inhibitory Effect of Methotrexate-Layered Double Hydroxide (LDH) Hybrid on Osteosarcoma Cell Lines / 대한정형외과학회잡지

PURPOSE: The purpose of this study was to observe and analyze the effect of Methotrexate-Layered Double Hydroxide (LDH) hybrids on growth inhibition and the apoptosis of human osteosarcoma cell lines (SaOS-2, MG-63) and normal fibroblasts. MATERIALS AND METHODS: FITC-LDH hybrids were added to the cells and incubated for 2, 4, 6, and 8 hours. The samples were examined by fluorescence microscopy. SaOS-2 and MG-63 cells, and a normal fibroblast cell line (Detroit 551) were treated with 500 g/mL MTX and 500 g/mL MTX-LDH hybrids for 24, 48, 72, and 96 hours, respectively. The proliferation was measured by using the MTT assay. Apoptosis was determined by DNA fragmentation analysis. RESULTS: The hybrids with LDH entered the cells effectively in a time- and dose-dependent manner. The proliferation of SaOS-2 cells in a culture treated with 500 g/mL of MTX-LDH hybrids for 24 hours was significantly inhibited (37% more) compared to those treated with MTX. MG-63 cell growth was inhibited 20% more than SaOS-2 cell growth. However, the difference in the degrees of inhibition of cells treated with MTXLDH hybrid or with MTX alone reduced with time. DNA ladders appeared in cells treated with 500 g/mL MTX-LDH hybrid for 24 hours but not in those treated with MTX and LDH alone. CONCLUSIONS: The results of this study suggest that MTX-LDH hybrid more effectively enters cells and inhibits their proliferation than MTX alone.

Evaluation of Porosity in Cylindrical Bone Cement Specimen Using Image Analysis System / 대한정형외과연구학회지

PURPOSE: The porosity of the bone cement is the most important cause of fatigue failure, the most common mode of failure of bone cement using widely in arthroplasty. It is important to evaluate the porosity of bone cement for improvement or development of bone cement, but the conventional 'stain, 'cut, and 'polish, manual method takes long time and efforts. So it is necessary to develop a new technique for evaluation of porosity of bone cement. We tried a technique using computer image analysis system to evaluate the porosity of bone cement specimen and assess efficacy of the method. Simultaneously we evaluated the relationship between the porosity of bone cement and fatigue failure. MATERIAL AND METHODS: We made 59, 2.5inch-length bone cement specimens(30 Simplex P, 29 Palacos R) using Simplex P and Palaces R which are widely using in clinical situation and checked radiogram using mammography film. After scanning the mammography film, we measured the porosity of the bone cement specimens using NIH(National Institute for Health) Image 1.6 version image analysis program. We also, measured the porosity of the bone cement specimens with conventional 'stain','cut' and 'polish' method, after then compared the results of two methods. Simultaneously, we evaluated the relationship between porosity & fatigue failure by loading 9.0, 10.0, 12.5 and 15.0 MPa load with frequency of 10Hz to the bone cement specimens under the physiologic condition. RESULTS: The coefficient of relation of simplex P and palaces R was 0.729 and 0.713 respectively, so there was high relationship between the image analysis system method and conventional one. It was easy and took shorter time to measure the porosity of bone cement specimens with image analysis system. There was high correlation between cement porosity and fatigue failure, regardless of level of load. CONCLUSION: It was very easy and fast to measure the porosity of the bone cement specimens with image analysis system and there was high correlation between cement porosity and fatigue failure.