• Journal of the Korea Convergence Society
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• v.7 no.2
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• pp.61-67
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• 2016

The olfactory system is an important model for the study of neuronal degeneration and regeneration, including neuronal diseases. When the olfactory sensory neurons are damaged by nerve injury or are exposed to environmental factors, they degenerate and are replaced by regenerating neurons. To monitor neuronal degeneration in living animal, we established an olfactory-specific GFP transgenic zebrafish. The effects of Triton X-100 or sodium acetate on the olfactory system were examined. A significant decrease in the number of GFP-positive olfactory sensory neurons was observed after chemical lesion. We found a recovery of GFP-positive neurons by 2 days posttreatment. From these results, we expect that further studies of olfactory degeneration and regeneration using this transgenic zebrafish will provide important advances for the study of neuronal degeneration and regeneration.

• Journal of Convergence for Information Technology
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• v.8 no.2
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• pp.61-65
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• 2018

Our experiment studied that grafted stem cells reduced behavioral deficiency in rodent animal models of clip compressive surgery inducing spinal cord infarction. Our research proved the effect of embryonic stem cells to the spinal cord infarction caused by compressing T9-10 with an aneurysm clip, focusing the application of grafted stem cells for reduction of infarction and regeneration of spinal cord nervous injury. Therefore, our research suggests manifest results that implantation of mouse embryonic stem cell could show behavioral improvement after severe spinal cord damage. Therefore, mouse embryonic stem cell (mESC) could be useful application for the method in neurological injury. Conclusively, stem cell implant therapy may enhance the effectiveness of stem cell implant for central nervous system injury.

• Clinical and Experimental Reproductive Medicine
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• v.36 no.4
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• pp.311-319
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• 2009

Objective: Human embryonic stem cells (hESCs) have the capacity to differentiate into all of the cell types and therefore hold promise for cell therapeutic applications. In order to utilize this important potential of hESCs, enhancement of currently used technologies for handling and manipulating the cells is required. The cryopreservation of hESC colonies was successfully performed using the vitrification and slow freezing-rapid thawing method. However, most of the hESC colonies were showed extremely spontaneous differentiation after freezing and thawing. In this study, we were performed to rapidly collect of early passage hESCs, which was thawed and had high rate of spontaneously differentiation of SNUhES11 cell line. Methods: Four days after plating, partially spontaneously differentiated parts of hESC colony were cut off using finely drawn-out dissecting pipette, which is mechanical separation method. Results: After separating of spontaneously differentiated cells, we observed that removed parts were recovered by undifferentiated cells. Furthermore, mechanical separation method was more efficient for hESCs expansion after thawing when we repeated this method. The recovery rate after removing differentiated parts of hESC colonies were 55.0%, 74.5%, and 71.1% when we have applied this method to three passages. Conclusion: Mechanical separation method is highly effective for rapidly collecting and large volumes of undifferentiated cells after thawing of cryopreserved early passage hESCs.

• Development and Reproduction
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• v.14 no.2
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• pp.43-50
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• 2010

Recently induced pluripotent stem (iPS) cells are derived from somatic cells by ectopic expression of several transcription factors (reprogramming factors) using technology of somatic cell reprogramming. iPS cells are able to selfrenew and differentiate into all type of cells in the body similarly to embryonic stem cells. Because iPS cells have advantages that can avoid immune rejection after transplantation and ethical issues unlike embryonic stem cells, research on iPS has made significant progress since the first report by Yamanaka in 2006. Nevertheless of many advantages of iPS, safer methods to introduce reprogramming factors into somatic cells must be developed due to safety concerns regarding viral vectors, and safer reprogramming factors to substitute the oncogenes should be evaluated for clinical application of iPS. Here we discuss the recent progress in reprogramming factors in embryonic stem cells, oocytes, and embryos, and discuss further research for finding new, more reliable and safer reprogramming factors.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.83-87
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• 2000

To investigate exhausted-medium-induced apoptosis in human corneal epithelial(HCE) cells, this study was performed DNA gel electrophoresis, M30 CytoDEATH staining and FAS-FAS ligand ELISA. SV-40 transfected cells were grown to confluency in culture for 7days. The supernatant was harvested and filtered with $0.22{\mu}m$ filter paper. Fresh HCE cells were exposed to the filtered exhausted medium for 1~2 days. Apoptotic cells were prepared for DNA extraction and run the agarose gel for DNA ladder pattern. M30 CytoDEATH was used a tool for easy and reliable determination of very early apoptosis in HCE cells. The control and exhausted medium were assayed for soluble FAS/FAS ligand protein by ELISA. HCE cells exposed to exhausted medium showed a typical DNA ladder pattern. Sporadic M30 CytoDEATH positive cells were detected among HCE cells exposed to exhausted medium. Soluble FAS/FAS ligand levels were not elevated in the exhausted medium compared to the fresh medium control. This study suggests that possible mechanism of exhausted medium induced apoptosis does not include the FAS-FAS ligand system.

• The Journal of the Korea Contents Association
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• v.14 no.6
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• pp.241-246
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• 2014

Acute promyelocytic leukemia (APL) is a cancer of the blood. Although electron beam (EB) irradiation is used with other anti-cancer agents, EB irradiation can be harmful to normal tissues around the cancer. In the present study, we evaluate the differential cytotoxic effect of EB irradiation with other molecules, including TNF-${\alpha}$, on DMSO-treated HL-60 cells and HL-60 cells. HL-60 cells are the human promyleocytic leukemia cell line and are differentiated by DMSO. DMSO-treated HL-60 cells are considered to be normal granulocytic cells. In these results, TNF-${\alpha}$ may be used as the potential agent for the treatment of blood cancer without side effects in low dose of EB irradiation therapy.

• Journal of Life Science
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• v.17 no.8 s.88
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• pp.1039-1045
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• 2007

Glioblastoma multiforme (GBM) is the most frequently occurring brain cancer. Although the existence of cancer stem cells (CSCs) in GBM has been established, there is little evidence to explain the link between CSCs and chemoresistance. In this study, we investigated that only a few cells of A172 and established GBM2 survived after 1,3-bis(2chloroethyl)-1-nitrosourea (BiCNU) exposures and these sur-vived cells resist the subsequent BiCNU treatment. In addition, these BiCNU-resistant small pop-ulations derived from GBM cells increased the phosphorylations of Erk and Akt and highly expressed CD133 stem cell surface marker. Furthermore, we observed that the BiCNU-resistant cancer cells de-rived from GBM have grown tumors when transplanted into severe combined immuno-deficient (SCID) mouse brain. These results demonstrate that BiCNU-resistant subpopulation cells derived from GBM have cancer stem-like cell properties. Therefore, it may provide provide further evidence that CSCs in GBM have chemotherapeutic drug resistance.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.70-70
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• 2002

형질전환 가축을 생산하기 위하여 최근 체세포 복제 기법을 이용하고 있다. 이러한 체세포를 이용한 형질전환 동물의 생산에는 체세포내에 유전자의 도입 효율이 직접적인 영향을 주게 된다. 따라서 본 연구는 세포내 유전자의 transfection 효율을 높이고자 한우의 체세포를 이용하여 여러 가지 조건에서 유전자 도입을 실시하였다. 세포내 유전자 도입 방법은 electroporation (EP) 방법을 이용하였다. 사용한 세포는 소의 귀세포(KbESF), 태아섬유아세포 (KbFF), 그리고 대조구로서 CHO cell을 이용하여 GFP 유전자를 도입하였다. EP는 0.4 cm cuvette을 사용하였고, voltage는 0.25 kV, 그리고 field strength 는 0.625 kV/cm 조건으로 실시하였으며, pulse times은 각각 1, 2, 또는 3회를 사용하였다. KbFF와 KbESF에서는 각각 pulse times을 증가시킬수록 유전자도입 세포수가 증가하였으나 (KbFF: 81, 634, 1,065 cells/$10^{6}$ cells, KbESF: 1,011, 5,567, 15,408 cells/$10^{6}$ cells), CHO cell에서는 pulse times을 증가시킬 수록 오히려 유전자도입 세포수가 감소하였다 (CHO: 1,591, 687, 297 cells/$10^{6}$ cells). 그리고 2주 동안 neo selection을 실시 한 결과 KbFF, KbESF, CHO에서 각각 93, 35, 184 colony가 선발되었으며, 이 중 65.6%, 8.6%, 4.3% 가 GFP 형광 발현 colony로 나타났다. 한편 CHO cell에서 transfection cell수가 감소된 것은 EP의 자극으로 인해 손상된 세포가 많이 발생한 것으로 나타났다. 또한 neo selection에서 선발된 colony중 GFP가 발현되지 않거나 일부만 발현되는 colony들이 많이 발생하였는데, 이것은 세포내 유전자가 transfection되지 않은 세포도 neo selection에서 선발된다는 것을 제시하고 있다. 따라서 체세포를 이용한 형질전환동물 생산을 위해서는 세포내 유전자 도입과 선발 과정에서 나타난 colony에 대하여 보다 엄격한 screen을 하는 것이 필요한 것으로 생각된다.

• The Korean Journal of Zoology
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• v.32 no.2
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• pp.163-175
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• 1989

Transferrin (Tf) has been known to exert profound effect on the myoblast differentiation in uirto. Therefore, the changes in the amount and affinity of the Tf receptor would accompany the myoblast differentiation. To investigate this possibility, we exarnined the afteration pattern in the level of the Tf receptor during the myoblast fusion. The level of Tf receptor was assayed by measuring the bound 125 I-Tf onto the surface of cultured myoblasts, and it was known that the level of Tf receptor reached the maximum at about 12 hr before the initi ation of the myoblast fusion and decreased as the differentiation proceeded, and that the affinity of Tf receptor to Tf was also decreased. In addition, various inhibitiors of the myoblast fusion also influenced the level of the Tf receptor. Accroding to these results, it is postulated that the level of Tf receptor is highly regulated during the myoblast differentiation.

• Korean Journal of Veterinary Research
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• v.36 no.4
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• pp.747-755
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• 1996

The regional distribution and relative frequencies of the gastro-entero-pancreatic endocrine cells were studied immunohistochemically in the GIT and pancreas of the Korean mole. Seven kinds of endocrine cells were identified in this study. Although 5-HT- and somatostatin-immunoreactive cells were seen throughout the GIT, they were most predominant in the pyloric gland region. Glucagon-immunoreactive cells were restricted on the large intestine. Bovine CG-immunoreactive cells were more frequent in the stomach than in the intestines which were not detected in the duodenum. Numerous Gas/CCK-immunoreactive cells were found in the pyloric gland region, but rarely in the jejunum and ileum. BPP-immunoreactive cells were observed to be rare in the stomach and ileum but were a few in number in the intestines. In the pancreas, four types, namely, glucagon-, somatostatin-, BPP- and insulin-immunoreactive cells were identified in the pancreatic islets and exocrine portion. These results suggest that although endocrine cells of the Korean mole is less abundant in the duodenum, the distribution pattern of its gastro-entero-pancreatic endocrine cells is similar to that reported for the Korean hedgehog.