• Development and Reproduction
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• v.17 no.4
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• pp.379-387
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• 2013

Embryonic stem (ES) cells can self-renew and differentiate to various cells depending on the culture condition. Although ES cells are a good model for cell type specification and can be useful for application in clinics in the future, studies on ES cells have many experimental restraints including low transfection efficiency and transgene expression. Here, we observed that transgene expression after transfection was enhanced by treatment with histone deacetylse (HDAC) inhibitors such as trichostatin A, sodium butyrate, and valproic acid. Transfection was performed using conventional transfection reagents with a retroviral vector encoding GFP under the control of CMV promoter as a reporter. Treatment of ES cells with HDAC inhibitors after transfection increased population of GFP positive cells up to 180% compared with untreated control. ES cells showed normal expression of stem cell markers after treatment with HDAC inhibitors. Transgene expression was further enhanced by modifying transfection procedure. GFP positive cells selected after transfection were proved to have the stem cell properties. Our improved protocol for enhanced gene delivery and expression in mouse ES cells without hampering ES cell properties will be useful for study and application of ES cells.

• Clinical and Experimental Reproductive Medicine
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• v.21 no.1
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• pp.77-81
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• 1994

To improve in vitro embryonic cell development, this study was desigend to culture in vitro fertilized early embryos of mouse in two different systems; conditioned medium alone and ampullary cells co-culture. Thirty two of 83 embryos(38.6%) were blocked in the 2 cell stage by co-culture, as compared to forty of 42 embryos(95.2%) in control group for 24hours culture. And all the embryonic cells cultured for conditioned medium alone were blocked for 48 hours culture. Twenty seven of 46 embryos (58.7 %) which overcome culture block in 2 cell stage by cocultured were developed morular and expanded blastocyst, and ninteen of 46 embryos(26.1 %) underwent hatching for 96 hours culture. The cellular fragmented rates for embryo were 26.2% in medium alone; 10 fragmented blastomere were graded mild status and 1 fragmented blastomere in severe status. On the other hand, the fragmented rate for 48 hours co-cultured were 15.7%03/83); 8 fragmented embryos were graded mild status, moderate status in 3 fragmented embryos and severe in 2 fragmented embryos respectively. In conclusion, the co-culture of embryos with ampullary cells is good to improve quality of embryos and overcome of culture block as well as development of cell cleavage.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2001.11a
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• pp.40-46
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• 2001

The use of pluripotent stem cells has tremendous advantages for various purposes but these cell lines with proven germ-line transmission have been completely established only in the mouse. Embryonic germ (EG) cell lines are also pluripotent and undifferentiated stem cells established from primordial germ cells (PGCs). This study was conducted to establish and characterize the chicken EG cells derived from gonadal primordial germ cells. We isolated gonadal PGCs from 5.5-day-old (stage 28) White leghorn (WL) embryos and established chicken EG cells lines with EG culture medium supplemented with human stem cell factor (hSCF), murine leukemia inhibitory factor (mLIF), bovine basic fibroblast growth factor (bFGF), human interleukin-11 (hIL-11), and human insulin-like growth factor-I (hIGF-I). These cells grew continuously for 4 months (10 passages) on a feeder layer of mitotically active chicken embryonic fibroblasts. These cells were characterized by screening with the Periodic acid-Shiff＇s reaction, anti-SSEA-1 antibody, and a proliferation assay after several passages. As the results, the chicken EG cells maintained characteristics of undifferentiated stem cells as well as that of gonadal PGCs. When cultured in suspension, the chicken EG cells successfully formed an embryoid body and differentiated into a variety of cell types when re-seeded onto culture dish. The chicken EG cells were injected into blastodermal layer at stage X and dorsal aorta of recipient embryo at stage 14 (incubation of 53hrs) and produced chimeric chickens with various differentiated tissues derived from the EG cells. The germline chimeras were also successfully induced by using EG cells. Thus, Chicken EG cells will be useful for the production of transgenic chickena and for studies of germ cell differentiation and genomic imprinting.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.3
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• pp.335-343
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• 2018

Objective: Remarkable difference in cellular activity was found between early and late subpassaged embryonic stem cell (ESCs) lines, which can be created by subtle changes in cell manipulation protocol. This study subsequently examined whether post-thaw subculture of early subpassaged ESC lines could further affect the activity of the ESCs. Methods: Fresh (as a control treatment) or cryopreserved F1 hybrid (B6CBAF1) early ESC lines (C57BL/6xCBA) of the 4 (P4) or the 19 passage (P19) were subcultured once, twice or six times under the same condition. The post-thaw survival of the ESCs was monitored after the post-treatment subculture and the ability of cell proliferation, reactive oxygen species (ROS) generation, apoptosis and mitochondrial ATP synthesis was subsequently examined. Results: Regardless of the subculture number, P19 ESCs showed better (p<0.05) doubling time and less ATP production than P4 ESCs and such difference was not influenced by fresh or cryopreservation. The difference between P4 and P19 ESC lines became decreased as the post-treatment subculture was increased and the six times subculture eliminated such difference. Similarly, transient but prominent difference in ROS production and apoptotic cell number was detected between P4 and P19 ESCs only at the 1st subculture after treatment, but no statistical differences between two ESC lines was detected in other observations. Conclusion: The results of this study suggest that post-thaw subculture of ESCs under the same environment is recommended for standardizing their cellular activity. The activity of cell proliferation ability and ATP synthesis can be used as parameters for quality control of ESCs.

• Toxicological Research
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• v.29 no.4
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• pp.221-227
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• 2013

Embryonic stem (ES) cells have potential for use in evaluation of developmental toxicity because they are generated in large numbers and differentiate into three germ layers following formation of embryoid bodies (EBs). In earlier study, embryonic stem cell test (EST) was established for assessment of the embryotoxic potential of compounds. Using EBs indicating the onset of differentiation of mouse ES cells, many toxicologists have refined the developmental toxicity of a variety of compounds. However, due to some limitation of the EST method resulting from species-specific differences between humans and mouse, it is an incomplete approach. In this regard, we examined the effects of several developmental toxic chemicals on formation of EBs using human ES cells. Although human ES cells are fastidious in culture and differentiation, we concluded that the relevancy of our experimental method is more accurate than that of EST using mouse ES cells. These types of studies could extend our understanding of how human ES cells could be used for monitoring developmental toxicity and its relevance in relation to its differentiation progress. In addition, this concept will be used as a model system for screening for developmental toxicity of various chemicals. This article might update new information about the usage of embryonic stem cells in the context of their possible ability in the toxicological fields.

• Clinical and Experimental Reproductive Medicine
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• v.40 no.3
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• pp.107-114
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• 2013

Homeobox genes play essential roles in embryonic development and reproduction. Recently, a large cluster of homeobox genes, reproductive homeobox genes on the X chromosome (Rhox) genes, was discovered as three gene clusters, ${\alpha}$, ${\beta}$, and ${\gamma}$ in mice. It was found that Rhox genes were selectively expressed in reproduction-associated tissues, such as those of the testes, epididymis, ovaries, and placenta. Hence, it was proposed that Rhox genes are important for regulating various reproductive features, especially gametogenesis in male as well as in female mammals. It was first determined that 12 Rhox genes are clustered into ${\alpha}$ (Rhox1-4), ${\beta}$ (Rhox5-9), and ${\gamma}$ (Rhox10-12) subclusters, and recently Rhox13 has also been found. At present, 33 Rhox genes have been identified in the mouse genome, 11 in the rat, and three in the human. Rhox genes are also responsible for embryonic development, with considerable amounts of Rhox expression in trophoblasts, placenta tissue, embryonic stem cells, and primordial germ cells. In this article we summarized the current understanding of Rhox family genes involved in reproduction and embryonic development and elucidated a previously unreported cell-specific expression in ovarian cells.

• Reproductive and Developmental Biology
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• v.34 no.1
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• pp.1-6
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• 2010

Mesenchymal stem cells (MSCs) have the multipotent capacity and this potential can be applied for obtaining valuable cell types which can use for cell therapy on various regenerative diseases. However, insufficient availability of cellular source is the major problem in cell therapy field using adult stem cell sources. Recently, human embryonic stem cells (hESCs) have been highlighted to overcome a limitation of adult cellular sources because they retain unlimited proliferation capacity and pluripotency. To use of hESCs in cell therapy, above all, animal pathogen free culture system and purification of a specific target cell population to avoid teratoma formation are required. In this study, we describe the differentiation of a mesenchymal stem cell-like cells population from feeder-free cultured hESCs(hESC-MSCs) using direct induction system. hESC-MSCs revealed characteristics similar to MSCs derived from bone marrow, and undifferentiated cell markers were extremely low in hESC-MSCs in RT-PCR, immunostaining and FACS analyses. Thus, this study proffer a basis of effective generation of specialized human mesenchymal stem cell types which can use for further clinical applications, from xenofree cultured hESCs using direct induction system.

• 대한생식의학회:학술대회논문집
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• 2004.06a
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• pp.51-51
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• 2004

• 대한생식의학회:학술대회논문집
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• 2001.11a
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• pp.63-70
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• 2001

• 대한생식의학회:학술대회논문집
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• 2001.03a
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• pp.161-165
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• 2001