Nondestructive Assessment of Glycosaminoglycans in Engineered Cartilages Using Hexabrix-Enhanced Micro-Computed Tomography

It is very useful to evaluate the content and 3D distribution of extracellular matrix non-destructively in tissue engineering. This study evaluated the feasibility of using micro-computed tomography (µCT) with Hexabrix to measure quantitatively sulfated glycosaminoglycans (GAGs) of engineered cartilage. Rabbit chondrocytes at passage 2 were used to produce artificial cartilages in polyglycolic acid scaffolds in vitro. Engineered cartilages were incubated with Hexabrix 320 for 20 min and analyzed via µCT scanning. The number of voxels in the 2D and 3D scanning images were counted to estimate the amount of sulfated GAGs. The optimal threshold value for quantification was determined by regression analysis. The 2D µCT images of an engineered cartilage showed positive correlation with the histological image of Safranin-O staining. Quantitative data obtained with the 3D µCT images of 14 engineered cartilages showed strong correlation with sulfated GAGs contents obtained by biochemical analysis (R² = 0.883, p < 0.001). Repeated exposure of engineered cartilages to Hexabrix 320 and µCT scanning did not significantly affect cell viability, total DNA content, or the total content of sulfated GAGs. We conclude that µCT imaging using Hexabrix 320 provides high spatial resolution and sensitivity to assess the content and 3D distribution of sulfated GAGs in engineered cartilages. It is expected to be a valuable tool to evaluate the quality of engineered cartilage for commercial development in the future.

The Effect of Non-Ionic Contrast Media on Q-T Interval and ST-T Wave of ECG during Coronary Angiography

BACKGROUND: During coronary angiography, some electrocardiographic changes occured due to contrast media, which do life threatening influences. METHODS: We compared the electrocardiographic changes which were induced by injection of three radiopaque contrast media during selective coronary angiography in 49 patients with chest pain. One of the contrast media was high osmolar ionic(Urografin_76) and the another was low osmolar ionic(Hexabrix) and the last was non-ionic(Ioversol). Electrocardiograms were obtained before, during and after selective coronary angiography. RESULTS: The changes of S-T segment or T were decreased in non-ionic group rather than high osmolar or ionic group. And there was significant Q-Tc interval prolongation among all three groups except comparision of low osmolar ionic contrast dye and non-ionic contrast dye in left coronary angiography. CONCLUSION: Non-ionic low osmolar contrast media was safer than high osmolar or ionic contrast medial because of lesser change of Q-Tc interval during selective coronary angiography.