• 대한생식의학회:학술대회논문집
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• 대한불임학회 2004년도 제46차 춘계학술대회
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• pp.70-71
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• 2004

• 대한생식의학회:학술대회논문집
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• 대한불임학회 2005년도 제48차 춘계 학술대회
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• pp.116.2-117
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• 2005

• 대한생식의학회:학술대회논문집
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• 대한불임학회 2002년도 제42차 춘계학술대회
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• pp.74.2-75
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• 2002

• 대한생식의학회:학술대회논문집
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• 대한불임학회 2002년도 제42차 춘계학술대회
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• pp.91.2-92
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• 2002

• Clinical and Experimental Reproductive Medicine
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• 제34권4호
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• pp.219-227
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• 2007

• 한국약용작물학회지
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• 제10권4호
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• pp.237-242
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• 2002

It was found that the purified extract from A. gigas Nakai (polysaccharide, M.W., 25 kD) controled differentiating human ES cells. Its optimal supplementation concentration was decided as 0.8 $({\mu}g/ml)$ to efficiently control the differentiation. It also enhanced the cell growth, compared to the control. However, most widely used and commercially available differentiating agent, Leukemia Inhibitory Factor (LIF) negatively affected on the cell growth even though it controls the differentiation of ES cells, down to 40-50 % based on morphological observation and telomerase activity. It was presumed that the extract first affected on cell membrane and resulted in controlling signal system, then amplify gene expression of telomere, which enhanced the telomerase activity up to three times compared to the control. LIF only increased the enzyme activity up to two times. It was confirmed that the extract from A. gigas Nakai could be used for substituting currently used differentiation controlling agent, LIF from animal resources as a cheap plant resource and not affecting the cell growth. It can broaden the application of the plants not only to functional foods and their substitutes but also to fine chemicals and most cutting-edge biopharmaceutical medicine.

• BMB Reports
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• 제54권10호
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• pp.505-515
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• 2021

Human pluripotent stem cells (hPSCs) include human embryonic stem cells (hESCs) derived from blastocysts and human induced pluripotent stem cells (hiPSCs) generated from somatic cell reprogramming. Due to their self-renewal ability and pluripotent differentiation potential, hPSCs serve as an excellent experimental platform for human development, disease modeling, drug screening, and cell therapy. Traditionally, hPSCs were considered to form a homogenous population. However, recent advances in single cell technologies revealed a high degree of variability between individual cells within a hPSC population. Different types of heterogeneity can arise by genetic and epigenetic abnormalities associated with long-term in vitro culture and somatic cell reprogramming. These variations initially appear in a rare population of cells. However, some cancer-related variations can confer growth advantages to the affected cells and alter cellular phenotypes, which raises significant concerns in hPSC applications. In contrast, other types of heterogeneity are related to intrinsic features of hPSCs such as asynchronous cell cycle and spatial asymmetry in cell adhesion. A growing body of evidence suggests that hPSCs exploit the intrinsic heterogeneity to produce multiple lineages during differentiation. This idea offers a new concept of pluripotency with single cell heterogeneity as an integral element. Collectively, single cell heterogeneity is Janus-faced in hPSC function and application. Harmful heterogeneity has to be minimized by improving culture conditions and screening methods. However, other heterogeneity that is integral for pluripotency can be utilized to control hPSC proliferation and differentiation.

• Asian-Australasian Journal of Animal Sciences
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• 제17권12호
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• pp.1641-1646
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• 2004

The objective of this study was to generate transgenic mice expressing human resistin gene by using the tetraploidembryonic stem (ES) cell complementation method. Human resistin gene was amplified from human fetal liver cDNA library by PCR, cloned into $pCR^{(R)}$ 2.1 $TOPO^{(R)}$ vector and constructed in pCMV-Tag4C vector. Mammalian expression plasmid containing human resistin was transfected into D3-GL ES cells by Lipofectamine 2,000, and then after 10-12 days of transfection, the human resistin-expressing cells were selected with G418. In order to produce tetraploid embryos, blastomeres of diploid embryos at the two-cell stage were fused with two times of electric pulse using 60 V 30 $\mu$sec (fusion rate: 2,114/2,256, 93.5%) and cultured up to the blastocyst stage (development rate: 1,862/2,114, 94.6%). The selected 15-20 ES cells were injected into tetraploid blastocysts, and then transferred into the uteri of E 2.5 d pseudopregnant recipient mice. To investigate the gestation progress, two E 19.5 mused fetuses were recovered by Cesarean section of which one fetus was confirmed to contain human resistin gene by genomic DNA-PCR. Therefore, our findings demonstrate that tetraploid-ES mouse technology can be considered as a useful tool to produce transgenic mice for the rapid analysis of gene function in vivo.

• Journal of Korean Neurosurgical Society
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• 제42권2호
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• pp.118-124
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• 2007

Objective : Adipose tissue is derived from the embryonic mesoderm and contains a heterogenous stromal cell population. Authors have tried to verify the characteristics of stem cell of adipose derived stromal cells (ADSCs) and to investigate immunohistochemical findings after transplantation of ADSC into rat brain to evaluate survival, migration and differentiation of transplanted stromal cells. Methods : First ADSCs were isolated from human adipose tissue and induced adipose, osseous and neuronal differentiation under appropriate culture condition in vitro and examined phenotypes profile of human ADSCs in undifferentiated states using flow cytometry and immunohistochemical study. Human ADSCs were transplanted into the healthy rat brain to investigate survival, migration and differentiation after 4 weeks. Results : From human adipose tissue, adipose stem cells were harvested and subcultured for several times. The cultured ADSCs were differentiated into adipocytes, osteoctye and neuron-like cell under conditioned media. Flow cytometric analysis of undifferentiated ADSCs revealed that ADSCs were positive for CD29, CD44 and negative for CD34, CD45, CD117 and HLA-DR. Transplanted human ADSCs were found mainly in cortex adjacent to injection site and migrated from injection site at a distance of at least 1 mm along the cortex and corpus callosum. A few transplanted cells have differentiated into neuron and astrocyte. Conclusion : ADSCs were differentiated into multilineage cell lines through transdifferentiation. ADSCs were survived and migrated in xenograft without immunosuppression. Based on this data, ADSCs may be potential source of stem cells for many human disease including neurologic disorder.

• 과학기술학연구
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• 제8권1호
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• pp.55-95
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• 2008

본 연구는 2000년부터 2002까지 진행된 세포응용연구사업단 설립과정을 토대로 배아줄기세포 연구를 둘러싼 기대역학구조를 분석하고자 시도되었다. 기대역학은 기대구성-재원확보-연구의무이행-기대구성의 과정이 반복적으로 나타나면서 구조화된다. 일반적으로 연구자들은 해당 연구결과에 대해 매우 신중하고 중립적인 태도를 보인다. 하지만 일부 관련 연구자들의 경우 과도한 전망을 제시하며 기대구성에 적극적인 모습을 보이는데 이는 재원확보와 윤리적 논쟁방어를 위한 역학창출이라는 전략적 관점에서 이해될 수 있다. 거대규모의 재원과 인력이 소요되는 생명공학연구개발의 경우 기대역학창출은 연구개발의 성패에 결정적인 요인으로 작용하기 때문에 이러한 전략구사는 더욱 중요한 의미를 갖게 된다. (배아)줄기세포를 둘러싼 연결망을 '기대역학'이라는 개념틀을 이용해 분석하게 되면 국내 (배아)줄기세포 연구자의 정체성이 좀 더 분명하게 드러나게 되고 정책담당자나 대중의 의사결정과정에 도움이 될 만한 의미 있는 결론에 도달할 수 있다.