Soon-Yong Kwon

Effect of Ascorbic Acid on Bone Marrow-Derived Mesenchymal Stem Cell Proliferation and Differentiation

Mesenchymal stem cells (MSCs) derived from bone marrow are an important tool in tissue engineering and cell-based therapies because of their multipotent capacity. Majority of studies on MSCs have investigated the roles of growth factors, cytokines, and hormones. Antioxidants such as ascorbic acid can be used to expand MSCs while preserving their differentiation ability. Moreover, ascorbic acid can also stimulate MSC proliferation without reciprocal loss of phenotype and differentiation potency. In this study, we evaluated the effects of ascorbic acid on the proliferation, differentiation, extracellular matrix (ECM) secretion of MSCs. The MSCs were cultured in media containing various concentrations (0-500 microM) of L-ascorbate-2-phosphate (Asc-2-P) for 2 weeks, following which they were differentiated into adipocytes and osteoblasts. Ascorbic acid stimulated ECM secretion (collagen and glycosaminoglycan) and cell proliferation. Moreover, the phenotypes of the experimental groups as well as the differentiation potential of MSCs remained unchanged. The apparent absence of decreased cell density or morphologic change is consistent with the toxicity observed with 5-250 microM concentrations of Asc-2-P. The results demonstrate that MSC proliferation or differentiation depends on ascorbic acid concentration.

Treatment of Chronic Dislocation of the Distal Radioulnar Joint: Comparative Studies Between Reconstruction and Resection of the Distal Ulna

From January 1981 until March 1990, a total of 32 cases of chronic dislocation of the distal radioulnar joint was treated surgically, and the follow-up results were compared between the group which underwent reconstruction and those who had resection of the distal ulna (the Darrach operation). The results obtained were as follows: (1) there was marked postoperative improvement in pain, range of motion, and grip strength in all 32 cases, and (2) in comparing the long-term follow-up results between the reconstruction (13 cases) and Darrach operation groups (19 cases), relief from pain was marked in the former, while the range of motion and grip strength scores were similar in both groups. It was concluded that the distal ulnar head and distal radioulnar joint were singularly important in preservation of normal wrist function. While various methods of treatment of distal radioulnar derangement are available, the results of reconstruction surgery are more favorable than those of the Darrach operation.