• BMB Reports
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• v.49 no.4
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• pp.197-198
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• 2016

Although three different research groups have reported successful derivations of human somatic cell nuclear transfer-derived embryonic stem cell (SCNT-ESC) lines using fetal, neonatal and adult fibroblasts, the extremely poor development of cloned embryos has hindered its potential applications in regenerative medicine. Recently, however, our group discovered that the severe methylation of lysine 9 in Histone H3 in a human somatic cell genome was a major SCNT reprogramming barrier, and the overexpression of KDM4A, a H3K9me3 demethylase, significantly improved the blastocyst formation of SCNT embryos. In particular, by applying this new approach, we were able to produce multiple SCNT-ES cell lines using oocytes obtained from donors whose eggs previously failed to develop to the blastocyst stage. Moreover, the success rate was closer to 25%, which is comparable to that of IVF embryos, so that our new human SCNT method seems to be a practical approach to establishing a pluripotent stem cell bank for the general public as well as for individual patients.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.2
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• pp.65-72
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• 2008

This work evaluated the extractability of tobacco stem biomass for the papermaking type Reconstituted Tobacco Sheet(RTS). The effects of the soaking conditions on the hydration of stem biomass and the effects of the hydrated state on the mechanical extraction were investigated. In order to simulate the mechanical expression process of a papermaking type RTS mill, for example, the screw press process, the novel mechanical pressing analyzer was developed for this study. The hydration of stem biomass by soaking process was greatly affected by the soaking time and the soaking temperature. The longer soaking time and the higher soaking temperature resulted in the higher hydrated stem biomass. Since the higher hydrated stem had more combined water in the inner structure and resulted in the more flexible structure, the higher hydrated stem leaded to the more compressed filter cake and the higher water contents in the filter cake after the mechanical pressing. The pilot pulping experiments showed the difference in hydration and extractability between burley and bright tobacco stem. The bulkier structure of the burley stem resulted in the faster hydration by pilot pulping and leaded to the larger reduction in water soluble components. And the hydration process showed the major influence on the separation efficiency of water soluble components.

• BMB Reports
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• v.55 no.1
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• pp.20-29
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• 2022

Stem cell-based therapy is a promising approach for treating a variety of disorders, including acute brain insults and neurodegenerative diseases. Stem cells such as mesenchymal stem cells (MSCs) secrete extracellular vesicles (EVs), circular membrane fragments (30 nm-1 ㎛) that are shed from the cell surface, carrying several therapeutic molecules such as proteins and microRNAs. Because EV-based therapy is superior to cell therapy in terms of scalable production, biodistribution, and safety profiles, it can be used to treat brain diseases as an alternative to stem cell therapy. This review presents evidences evaluating the role of stem cell-derived EVs in stroke, traumatic brain injury, and degenerative brain diseases, such as Alzheimer's disease and Parkinson' disease. In addition, stem cell-derived EVs have better profiles in biocompatibility, immunogenicity, and safety than those of small chemical and macromolecules. The advantages and disadvantages of EVs compared with other strategies are discussed. Even though EVs obtained from native stem cells have potential in the treatment of brain diseases, the successful clinical application is limited by the short half-life, limited targeting, rapid clearance after application, and insufficient payload. We discuss the strategies to enhance the efficacy of EV therapeutics. Finally, EV therapies have yet to be approved by the regulatory authorities. Major issues are discussed together with relevant advances in the clinical application of EV therapeutics.

• International Journal of Oral Biology
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• v.37 no.2
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• pp.43-50
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• 2012

The use of high throughput screening (HTS) in drug development is principally for the selection new drug candidates or screening of chemical toxicants. This system minimizes the experimental environment and allows for the screening of candidates at the same time. Umbilical cord-derived stem cells have some of the characteristics of fetal stem cell and have several advantages such as the ease with which they can be obtained and lack of ethical issues. To establish a HTS system, optimized conditions that mimic typical cell culture conditions in a minimal space such as 96 well plates are needed for stem cell growth. We have thus established a novel HTS system using human umbilical cord derived-mesenchymal stem cells (hUC-MSCs). To determine the optimal cell number, hUC-MSCs were serially diluted and seeded at 750, 500, 200 and 100 cells per well on 96 well plates. The maintenance efficiencies of these dilutions were compared for 3, 7, 9, and 14 days. The fetal bovine serum (FBS) concentration (20, 10, 5 and 1%) and the cell numbers (750, 500 and 200 cells/well) were compared for 3, 5 and 7 days. In addition, we evaluated the optimal conditions for cell cycle block. These four independent optimization experiments were conducted using an MTT assay. In the results, the optimal conditions for a HTS system using hUC-MSCs were determined to be 300 cell/well cultured for 8 days with 1 or 5% FBS. In addition, we demonstrated that the optimal conditions for a cell cycle block in this culture system are 48 hours in the absence of FBS. In addition, we selected four types of novel small molecule candidates using our HTS system which demonstrates the feasibility if using hUC-MSCs for this type of screen. Moreover, the four candidate compounds can be tested for stem cell research application.

• Food Science and Preservation
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• v.7 no.1
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• pp.108-112
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• 2000

Proximate composition , volatile compounds, free amino acids, fatty acids and inorganic compounds in leaf, stem and root of Houttyunia cordata Thunb cultivated from two different area, Bosung and Sunchon , were analyzed. Each part of Houttuynia cordata Thunb from both local area showed moisture contents of 80-84% and crude ash contents of 2.1 ∼2.8%. Crude fat and protein contents were less than 3 % showing slightly higher contents in leaf than in both stem and root . Twenty six volatile compunds were identified from the parts of the plant, the volatile contents were high in the oder of leaf, root and stem. Major volatile compounds were mostly derivatives of decanoic acid ; decanoic acid, 20 tridecanoie, decanal and dodecanoic acid. Of free amino acids in leaf asparagine was the highest, while in stem hydroxyproline, proline and arginine were the major free amino acids. Linoleic acid was the highest in the stem and root, and linolenic acid was highest in leaf. the major minerals of all parts were K, Ca. Mg, P, Fe, Zn and Cu, showing highest with K.

• Journal of Life Science
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• v.10 no.1
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• pp.68-73
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• 2000

In order to develop new materials for the functional food, the components of safflower(Carthamus tinctorius L.) sprout was studied. Chemical composition, minerals, amino acids, and fatty acids of the leaf and the stem parts of 2 weeks grown safflower sprout were analyzed. The chemical composition of safflower spout was 12.7% (w/w) moisture, 28.5% crude protein, 10.1% crude fat, and 5.3% crude ash. Mineral contents of the leaf part were P 49%, K 22%, Mg 15%, Ca 10% whereas these of the stem part were K 51%, P 27%, S 10%, Ca 7%, Mg 4%. Other mineral contents were less than 2% in both parts. Especially, Pt was 0.18 ppb and 0.17 ppb in the leaf and the stem parts, respectively. The composition of the amino acid were approximately as follow, the major amino acid in the leaf and the stem were aspartic acid and glutamic acid, the contents of these were 10.7mg/g, 10mg/g in the leaf, 11.3 mg/g, 8.4 mg/g in the stem, respectively. The major fatty acids in the leaf and the stem parts were linoleic acid and $\alpha$-linolenic acid. The linoleic acid (C18:2) in the leaf and the stem parts were 67% (w/w) and 47% whereas the $\alpha$-linolenic acid. The linoleic acid (C18:2) in those parts were 14% (w/w) and 11%, respectively. On the basis of chemical analysis, the safflower sprout showed to have relatively high contents of crude protein and crude fat, minerals including small amount of Pt, polyunsaturated fatty acid as linoleic acid and $\alpha$ -linolenic acid. These results suggested that safflower sprout was found to be a useful material of natural health food for the functional food development.

• Biomedical Science Letters
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• v.27 no.1
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• pp.1-11
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• 2021

Cancer stem cells, which are known to drive tumor formation and maintenance, are a major obstacle in the effective treatment of various types of cancer. Trans-membrane glycoprotein mucin 1 antigen and cell surface glycogen CD44 antigen are well-known surface markers of breast cancer cells and breast cancer stem cells, respectively. To effectively treat cancer cells and cancer stem cells, we developed a new drug-encapsulating liposome conjugated with dual-DNA aptamers specific to the surface markers of breast cancer cells and their cancer stem cells. These two aptamer (Apt)-targeted liposomes, which were prepared to encapsulate doxorubicin (Dox), were named "Dual-Apt-Dox". Dual-Apt-Dox is significantly more cytotoxic to both cancer stem cells and cancer cells compared to liposomes lacking the aptamers. Furthermore, we demonstrated the inhibitory efficacy of Dual-Apt-Dox against the experimental lung metastasis of breast cancer stem cells and cancer cells in athymic nude mice. We also showed the potent antitumor effects of dual-aptamer-conjugated liposome systems by targeting cancer cells as well as cancer stem cells. Thus, our data indicate that dual-aptamer-conjugated liposome systems can prove to be effective drug delivery vehicles for breast cancer therapy.

• Journal of Korean Neurosurgical Society
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• v.29 no.5
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• pp.684-687
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• 2000

Primary anaplastic oligodendroglioma in brain stem is extremely rare. The authors present a case of a anaplastic oligodendroglioma arising from pons. A 29 year-old male patient was admitted because of cranial nerve palsy and visual disturbance. Neurological examination revealed bilateral sixth and left seventh cranial nerve plasies. Near-total resection of tumor mass was performed through midline suboccipital appraoch. Tumor was not related with choroid plexus and major vessels but it was firmly attached to the fourth ventricle floor. Tumor was considered to be arised from the tegmental portion of pons, growing dorsally into the 4th ventricle. Hitopathological exmination revealed primary anaplastic oligodendroglioma. Postoperative course was uneventful. The authors believe that this type of tumor with dorsally growing pattern can be successfully resected without major neurological deficit.

• Journal of the Korean Society of Tobacco Science
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• v.8 no.2
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• pp.51-66
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• 1986

Volatile aroma components, non-volatile organic acids in lamina and stems of flue-cured(NC 2326) and burley ( Burley 21) were analyzed by gas chromatography and mass spectrometry, respectively. Then compositional differences of these components between lamina and stems were discussed. The contents of volatile components were higher in flue-cured than in burley tobacco, and it was also higher in lamina then in stem. The major aroma components in lamina were neophytadiene , nicotine, solanone and benzyl alcohol but those in stems were palmitic acid, neophytadiene, nicotine, solanone and phenyl ethyl acetate. On the other hand, the contents of non-volatile organic acids were higher in burley than in flue-cured tobacco, and these values of burley tobacco were higher in lamina than in stem but flue-cured tobacco were higher in stem than in lamina. The major acids in all the above four tabacco samples were malic, citric, oxalic and linolenic acid.

• Molecules and Cells
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• v.46 no.12
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• pp.727-735
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• 2023

Stem cells require high amounts of energy to replicate their genome and organelles and differentiate into numerous cell types. Therefore, metabolic stress has a major impact on stem cell fate determination, including self-renewal, quiescence, and differentiation. Lysosomes are catabolic organelles that influence stem cell function and fate by regulating the degradation of intracellular components and maintaining cellular homeostasis in response to metabolic stress. Lysosomal functions altered by metabolic stress are tightly regulated by the transcription factor EB (TFEB) and TFE3, critical regulators of lysosomal gene expression. Therefore, understanding the regulatory mechanism of TFEB-mediated lysosomal function may provide some insight into stem cell fate determination under metabolic stress. In this review, we summarize the molecular mechanism of TFEB/TFE3 in modulating stem cell lysosomal function and then elucidate the role of TFEB/TFE3-mediated transcriptional activity in the determination of stem cell fate under metabolic stress.