• Journal of Korean Foot and Ankle Society
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• v.18 no.3
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• pp.100-107
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• 2014

Purpose: The purpose of this study is to evaluate the efficacy of mesenchymal stem cell (MSC) isolation by the magnetic-activated cell sorting (MACS) method in tendon tissue-derived cells compared to the colony picking method for isolation of MSCs by picking colony-forming cells. Materials and Methods: Human tendon-derived cells were isolated by enzyme digestion using normal tendon tissues from three donors. We used the magnetic kit and well-known MSC markers (CD90 or CD105) to isolate MSCs in tendon-derived cells using MACS. Cloning cylinders were used to isolate colony-forming cells having MSC characteristics in tendon-derived cells. Colony-forming unit-fibroblast (CFU-F) assay was used to evaluate the self-renewal capacity of cells isolated using the colony picking method or MACS. For comparison of differentiation potentials into osteogenic or adipogenic lineage between two groups, alizarin red S and oil red O staining were performed at 14 days after induction of differentiation in vitro. Results: Flow cytometry results showed that early passage tendon-derived cells expressed CD44 in 99.13%, CD90 in 56.51%, and CD105 in 86.19%. In the CFU-F assay, CD90+ or CD105+ cells isolated with MACS showed larger colony formation in size than cells isolated using the colony picking method. We also observed that CD90+ or CD105+ cells were constantly differentiated into both osteogenic and adipogenic lineages in cells from all donors, whereas cells isolated using the colony picking method were heterogeneous in differentiation potentials to the osteogenic and adipogenic lineages. Conclusion: CD90+ or CD105+ cells isolated using MACS showed superior MSC characteristics in the self-renewal and multi-differentiation capacities compared with cells isolated using the colony picking method.

• IMMUNE NETWORK
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• v.1 no.1
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• pp.87-94
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• 2001

Background: Cytokine-mediated ex vivo expansion has been proposed as a means of increasing the number of cord blood (CB) hematopoietic stem cells for transplantation. As well as stem cell number, stromal cells are necessary for functional maturation of hematopoiesis. The purpose of this study was to analyze the development of stromal cells during ex vivo expansion of CB $CD34^+$ cells. Methods : $CD34^+$ cells were purified from CB by magnetic bead selection. The levels of of interleukin-3, interleukin-$1{\beta}$, interleukin-6, granulocyte macrophagecolony stimulating factor and tumor necrosis factor-${\alpha}$ were measured in culture supernatants on 0, 1, 2, and 3 weeks, using ELISA techniques. CB $CD34^+$ cells were expanded in Iscoves modified Dulbeccos medium in the presence of several cytokines. The expression of E-selectin, vascular cell adhesion molecule-1, intercellular adhesion molecule-1, platelet/endothelial cell adhesion molecule-1, von Willebrand factor, vimentin, and CD14 in newly developed stromal cells was examined by immunocytochemical method. Relevant extracellular matrix (ECM) proteins and proper cytokines were also assayed for the most suitable condition for expansion of stromal cells. Results: Several cytokines were found to have been produced by CB $CD34^+$ cells as well as bone marrow-derived $CD34^+$ cells. During ex vivo expansion of CB $CD34^+$ cells, stromal cells appeared in the culture by day 4 and expanded over the following 7-10 days before being confluent by day 2 1. These cells expressed surface markers characteristic of cells of endothelial lineage. Furthermore, these stroaml cells also expanded effectively when treated with thrombopoietin+flt-3 ligand+stem cell factor+leukemia inhibitory factor or 0.1% poly-L-lysine-coated wells. Conclusion: Stromal cells were developed during ex vivo expansion of CB $CD34^+$ cells and that this development could be enhanced further by treating the stromal cells with cytokines or ECM.

• Journal of Animal Science and Technology
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• v.44 no.2
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• pp.181-190
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• 2002

This study was performed to determine sequences of the mt DNA D-loop region, including $tRNA^{Pro}$ and $tRNA^{Pre}$ and to analysis sequence variation polymorphism in Korean cattle. The resulting sequencies were compared with previously published sequences for other cattle breeds(GenBank J01394). The PCR was used to amplify an 1142bp between nucleotides 15061 and 404 within the D-loop region of mt DNA using specific primers. Korean cattle showed 24 polymorphic sites by nucleotide substitutions and insertions of single base pairs. About 50% of polymorphic sites were found in positions 16042 to 16122 with the most variable region. Among these polymorphic sites, variations at 16055, 16230 and 16260 bp were detected as new sequence variants in Korean cattle. These specific polymorphic sites have not been reported in the Japanese black cattle and European cattle. Therefore, mt DNA variants in the D-loop region may be used as genetic markers for specifying Korean cattle. The frequencies of positions 169, 16302, 16093, 16042, 16119 with a high level of sequence polymorphism were 0.81, 0.56, 0.56, 0.50 and 0.43, respectively. In comparison of genetic distances, Korean cattle showed the more closely to European cattle as Bos taurus than Bos indicus such as African and India breeds. In conclusion, these mt DNA sequence polymorphisms in the D-loop region for Korean cattle may be useful for the analysis of cytoplasmic genetic variation and associations with economic important traits and genetic analysis of maternal lineage.

• Development and Reproduction
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• v.12 no.1
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• pp.1-8
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• 2008

Specific protocols to increase the differentiation of neuronal cells from embryonic stem (ES) cells have been well established, such as retinoic acid induction and lineage selection of neuronal cells. For the neuropathological studies, ES-derived neurons (ES neurons) must show normal physiological characteristics related to cell death and survival and should be maintained in vitro for a sufficient time to show insults-specific cell death without spontaneous death. When mouse ES cells were plated onto astrocytes monolayer after retinoic acid induction, most ES cells differentiated into neuronal cells, which were confirmed by the presence of specific neuronal markers, and the cultures were viable for at least four weeks. When these cultures were examined for vulnerability to glutamate excitotoxicity, ES neurons were vulnerable to excitotoxic insults mediated by agonist-specific receptors. The vulnerability to excitotoxic death increased with developmental age of ES neurons in vitro. Specific receptors for Neurotrophin and GDNF family ligands were present in ES neurons. GDNF and NT-3 could modulate the survival and excitotoxic vulnerability of ES neurons. The vulnerability and resistance to toxic insults, which are essential requirements of model culture systems for neuropathological studies, make ES neurons to a useful model culture system. Especially ES cell are highly amenable to genetic modification unlikely to primary neuronal cells, which will give us a chance to answer more complicated neurophysiological questions. Recently there was an outstanding attempt to explore the cellular toxicity using human ES cells (Schrattenholz & Klemm, 2007) and it suggested that ES cells could be a new model system for neurophysiological studies soon and go further a large-scale screening system for pharmacological compounds in the future.