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The present study was conducted to test a hypothesis that the ex vivo supplementation of TGF-beta1 into medium will significantly improve the mechanical properties of the fibrous tissue regenerated in the patellar tendon defect after transplantation of cultured autologous synovium-derived fibroblasts. Thirty rabbits were divided into the following three groups. In Group A, we applied phosphate buffered saline of 0.1 ml to the defect created in the patellar tendon. In Group B, we transplanted autologous fibroblasts, which had been cultured into the tendon defect. In Group C, we transplanted autologous fibroblasts, which had been cultured with supplementation of TGF-beta1, into the tendon defect. Animals were killed at 6 weeks, and the regenerated tissue was examined for biomechanics and histology. The tangent modulus and the tensile strength of Group C were significantly higher than that of Group B, while the tensile strength of Group C was significantly lower than that of Group A. Histologically, vascular formation was abundantly found in the regenerated tissue of Groups B and C as compared to the regenerated tissues in Group A. The present study showed that transplantation of cultured autologous synovium-derived fibroblasts enhanced vascular formation in the fibrous tissue regenerated in the patellar tendon defect, while cell transplantation deteriorated the mechanical properties of the regenerated fibrous tissue. However, the ex vivo supplementation of TGF-beta1 into the medium significantly decreased mechanical deterioration of the fibrous tissue regenerated in the tendon defect after transplantation of cultured autologous synovium-derived fibroblasts.

A significant breakdown of the rectification characteristic of the ZnO-Si02-Au device occurs with UV irradiation and is enhanced with increasing light intensity and a reverse bias voltage at which the device is kept under UV irradiation. Complex impedance plots of the device reveal that an increase in leakage current observed after UV irradiation is mainly due to a decrease in the barrier height. The magnitude of breakdown and recovery of the rectification characteristic is dependent on the ambient partial pressure of oxygen. The variation of the barrier height is explained by oxygen desorption under UV illumination and by oxygen adsorption in the dark.