Ki-Jun Hwang

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OBJECTIVES To characterize mesenchymal stem cell-like cells isolated from human amniotic fluid for a new source of therapeutic cells. MATERIALS Fibroblastoid-type cells obtained from amniotic fluid at the time of birth. METHODS The ability of ex vivo expansion was investigated until senescence, and stem cell-like characteristics were analyzed by(More)
In human in-vitro fertilization (IVF)-embryo transfer, the in-vitro culture environment differs from in-vivo conditions in that the oxygen concentration is higher, and in such conditions the mouse embryos show a higher concentration of reactive oxygen species (ROS) in simple culture media. ROS are believed to cause damage to cell membranes and DNA(More)
Acteoside extracted from the leaves of Rehmannia glutinosa was examined to determine the mechanism(s) of its antioxidant properties. The deoxyribose assay system showed that acteoside has a high redox potential as electron donor, which generates hydroxyl radicals in an Fe3+-dependent manner similar to ascorbic acid. However, the antioxidant properties of(More)
OBJECTIVE(S) To elucidate the relationship between intracellular H2O2 production and embryo development in different oxygen culture conditions. METHODS Pronuclear stage embryos were obtained from C57BL/CBA F1 and ICR mice. Measurement of H2O2 level was performed with 2',7'-dichlorodihydroflourescein diacetate and the number of blastomeres was counted(More)
The antifungal activity of Portulaca oleracea extracts against hyphal growth of various fungi was evaluated in real time using an automatic single-cell bioassay system. Target organisms were the filamentous fungi Aspergillus and Trichophyton and the yeast Candida. A colony of test fungi was in contact with the assay medium, or assay medium containing plant(More)
Endometrial decidualization results from the differentiation of stromal cells in an ovarian steroid-sensitive manner. Human endometrial tissues obtained from fertile women at various stages of the menstrual cycle were subjected to immunohistochemistry to localize the components of the transforming growth factor-beta (TGF-beta) system. TGF-beta receptor-I(More)
In previous studies, the biological characteristics of the fungus Cladosporium phlei and its genetic manipulation by transformation were assessed to improve production of the fungal pigment, phleichrome, which is a fungal perylenequinone that plays an important role in the production of a photodynamic therapeutic agent. However, the low production of this(More)
Bioisostere approach has been shown to be useful to augment potency or to modify certain physiological properties of a lead compound. Based upon well documented bioisosterism, an isosteric replacement of benzene ring of 4-hydroxy-2-quinolone compound (L-695902) with a thiophene moiety was carried out to prepare the title compounds,(More)
UV-mutagenesis was performed to obtain mutant strains that demonstrate altered production of phleichrome, a secondary metabolite of Cladosporium phlei. Among fifty mutants selected, based on the increased area and intensity of the purple pigment surrounding the colonies, the strain M0035 showed the highest production of phleichrome, more than seven fold(More)
AIMS The objective of this study was to evaluate recombinant 56-kDa outer membrane protein as a potential inhibitor to infection from Orientia tsutsugamushi. METHODS AND RESULTS The 56-kDa protein was cloned and expressed in an Escherichia coli system, and the degree of target cell attachment to immobilized 56-kDa protein was measured in a cell adhesion(More)