• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.12 no.4
• /
• pp.252-263
• /
• 1983

In the briquet-burning hot water boiler the $SO_x$-dew point is calculated and found to be between $130^{\circ}C\;and\;154^{\circ}C$. The corrosion rate depends on the surface temperature and the concentration of the condensate on the surface. The concentration of the condensate is decided acoording to the difference detween $SO_x$-dew point and the surface temperature. When the surface temperature is $80^[\circ}C$, the concentration of the condensate is also high (0.15N). Therefore the high concentration and high temperature promote the high corrosion rate of $14{\times}13^{-3}g/100cm^2{\cdot}hr$ on the SS41 material. On the other hand, when the surface temperatures are $60^{\circ}C\;and\;40^{\circ}C$, the concentrations and the co..sion rates are reduced dramatically to $0.11\;N,\;8.6{\tiems}10^{-3}g/100cm^2{\cdot}hr$ and $5{\tiems}10^{-4}g/100cm^2{\cdot}hr$ respectively.

• Reproductive and Developmental Biology
• /
• v.31 no.4
• /
• pp.267-272
• /
• 2007

Human embryonic stem (ES) cells are derived from the inner cell mass of the preimplantation embryo and have the capacity to differentiate into various types of cells in the body. Hence, these cells may potentially be an indefinite source of cells for cell therapy in various degenerative diseases including neuronal disorders. For clinical applications of human ES cells, directed differentiation of these cells would be necessary. The objective of this study is to develop the culture condition for the expansion of neural precursor cells derived from human ES cells. Human ES cells were able to differentiate into neural precursor cells upon a stepwise culture condition. Neural precursor cells were propagated up to 5000-fold in cell numbers over 12-week period of culture and evaluated for their characteristics. Expressions of sox1 and pax6 transcripts were dramatically up-regulated along the differentiation stages by RT-PCR analysis. In contrast, expressions of oct4 and nanog transcripts were completely disappeared in neural precursor cells. Expressions of nestin, pax6 and sox1 were also confirmed in neural precursor cells by immunocytochemical analysis. Upon differentiation, the expanded neural precursor cells differentiated into neurons, astrocytes, and oligodendrocytes. In immunocytochemical analysis, expressions of type III ${\beta}$-tubulin and MAP2ab were observed Presence of astrocytes and oligodendrocytes were also confirmed by expressions of GFAP and O4, respectively. Results of this study demonstrate the feasibility of long-term expansion of human ES cell-derived neural precursor cells in vitro, which can be a potential source of the cells for the treatment of neurodegenerative disorders.

• Clinical and Experimental Reproductive Medicine
• /
• v.35 no.1
• /
• pp.39-48
• /
• 2008

Objective: The aim of this study was to investigate whether multipotent germline stem cells (MGSCs) can be established from neonatal mouse testis. Methods: Various cells containing MGSCs were collected from neonatal testis of ICR mice and allocated to plates for in vitro culture. After 7 days in culture, the cells were passed to a fresh culture plate and continuously cultured. From the third or fourth passage, the presumed MGSCs were cultured and maintained on mitomycin C-inactivated STO feeder cells. The MGSCs were cultured in a condition where mouse embryonic stem cells (ESCs) are cultured. Characteristics of the MGSCs were evaluated by RT-PCR, immunocytochemistry, alkaline phosphatase activity, karyotyping, and transmission electron microscopy. Results: Two MGSCs lines were established from 9 pooled sets of neonatal testicular cells. MGSCs colonies were morphologically undistinguishable from ESCs colonies and both MGSC lines as well as ESCs expressed undifferentiated stem cell markers, such as Thy-1, Oct-4, Nanog, Sox2 and alkaline phosphatase. Fine structure of undifferentiated MGSCs were similar to those of ESCs and 60% of MGSCs (12/20) had normal karyotype at passage 10. They were able to form embryoid bodies (EBs) and MGSC-derived EBs expressed marker genes of three germ layers. Conclusion: We could establish the MGSCs from neonatal mouse testis and they were differentiated to multipotent lineages of three germ layers. Molecular characteristics of MGSCs were similar to those of ESCs. Our results suggest a possibility that multipotent stem cells derived from testis, the MGSCs, could replace the ESCs in biotechnology and regenerative medicine.

• Korean Journal of Microbiology
• /
• v.53 no.4
• /
• pp.320-322
• /
• 2017

A betaproteobacterium strain GR16-43 was isolated from a surface layer of the Geomnyong Pond in Republic of Korea by a dilution-to-extinction culturing method. We report the whole genome sequence of the strain GR16-43, which contains 4,806,848 bp with a G + C content 67.12%, and to include 4,424 protein-coding genes and 47 transfer RNA genes. The genome was determined to contain the genes encoding carbon monoxide dehydrogenase, nitrate reductase, nitrite reductase, nitric oxide reductase, and the sulfur oxidation (sox) gene cluster, highlighting the potential importance of the bacterial group represented by the strain in the cycling of inorganic elements. These results indicate that strain GR16-43 genome showed several traits indicating adaptation of the bacteria to living in freshwater environments.

• BMB Reports
• /
• v.53 no.12
• /
• pp.622-627
• /
• 2020

Cancer stem cells (CSCs) or tumor-initiating cells are thought to play critical roles in tumorigenesis, metastasis, drug resistance, and tumor recurrence. For the diagnosis and targeted therapy of CSCs, the molecular identity of biomarkers or therapeutic targets for CSCs needs to be clarified. In this study, we identified CD166 as a novel marker expressed in the sphere-forming CSC population of A2780 epithelial ovarian cancer cells and primary ovarian cancer cells. The CD166+ cells isolated from A2780 cells and primary ovarian cancer cells highly expressed CSC markers, including ALDH1a1, OCT4, and SOX2, and ABC transporters, which are implicated in the drug resistance of CSCs. The CD166+ cells exhibited enhanced CSC-like properties, such as increased sphere-forming ability, cell migration and adhesion abilities, resistance to conventional anticancer drugs, and high tumorigenic potential in a xenograft mouse model. Knockdown of CD166 expression in the sphere-forming ovarian CSCs abrogated their CSC-like properties. Moreover, silencing of CD166 expression in the sphere-forming CSCs suppressed the phosphorylation of focal adhesion kinase, paxillin, and SRC. These results suggest that CD166 plays a key role in the regulation of CSC-like properties and focal adhesion kinase signaling in ovarian cancer.

• Journal of Embryo Transfer
• /
• v.29 no.1
• /
• pp.91-99
• /
• 2014

Oxygen consumption is a useful parameter for evaluating mammalian embryo quality, since individual bovine embryos was noninvasively quantified by scanning electrochemical microscopy (SECM). Recently, several approaches have been used to measure the oxygen consumption rates of individual embryos, but relationship between oxygen consumption and pregnancy rates of Hanwoo following embryo transfer has not yet been reported. In this study, we measured to investigate the correlation between oxygen consumption rate and pregnancy rates of Hanwoo embryo using a SECM. In addition to, the expression of pluripotent gene and anti-oxidant enzyme was determined using real-time PCR by extracting RNA according to the oxygen consumption of in vivo embryo. First, we found that the oxygen consumption significantly increased in blastocyst-stage embryos (blastocyst) compared to early blastocyst stage embryos, indicating that oxygen consumption reflects the embryo quality (Grade I). Oxygen consumption of blastocyst was measured using a SECM and total cell number of in vitro blastocyst was enumerated by counting cells stained by propidium iodide. The oxygen consumption or GI blastocysts were significantly higher than those of GII blastocysts ($10.2{\times}10^{15}/mols^{-1}$ versus $6.4{\times}10^{15}/mols^{-1}$, p<0.05). Total cell numbers of in vitro blastocysts were 74.8, 90.7 and 110.2 in the oxygen consumption of below 10.0, 10.0~12.0 and over $12.0{\sim}10^{15}/mols^{-1}$, respectively. Pregnant rate in recipient cow was 0, 60 and 80% in the transplantation of embryo with the oxygen consumption of below 10.0, 10.0~12.0 and over $12.0{\times}10^{15}/mols^{-1}$, respectively. GPX1 and SOD1 were significantly increased in over -10.0 group than below 10.0 groups but in catalase gene, there was no significant difference. On the other hand, In OCT-4 and Sox2, pluripotent gene, there was a significant difference (p<0.05) between the below-10.0 ($0.98{\pm}0.1$) and over 10.0 ($1.79{\pm}0.2$). In conclusion, these results suggest that measurement of oxygen consumption maybe help increase the pregnant rate of Hanwoo embryos.

• BMB Reports
• /
• v.54 no.10
• /
• pp.528-533
• /
• 2021

Osteoarthritis (OA) is a degenerative disorder that can result in the loss of articular cartilage. No effective treatment against OA is currently available. Thus, interest in natural health products to relieve OA symptoms is increasing. However, their qualities such as efficacy, toxicity, and mechanism are poorly understood. In this study, we determined the efficacy of avenanthramide (Avn)-C extracted from oats as a promising candidate to prevent OA progression and its mechanism of action to prevent the expression of matrix-metalloproteinases (MMPs) in OA pathogenesis. Interleukin-1 beta (IL-1β), a proinflammatory cytokine as a main causing factor of cartilage destruction, was used to induce OA-like condition of chondrocytes in vitro. Avn-C restrained IL-1β-mediated expression and activity of MMPs, such as MMP-3, -12, and -13 in mouse articular chondrocytes. Moreover, Avn-C alleviated cartilage destruction in experimental OA mouse model induced by destabilization of the medial meniscus (DMM) surgery. However, Avn-C did not affect the expression of inflammatory mediators (Ptgs2 and Nos) or anabolic factors (Col2a1, Aggrecan, and Sox9), although expression levels of these genes were upregulated or downregulated by IL-1β, respectively. The inhibition of MMP expression by Avn-C in articular chondrocytes was mediated by p38 kinase and c-Jun N-terminal kinase (JNK) signaling, but not by ERK or NF-κB. Interestingly, Avn-C added with SB203580 and SP600125 as specific inhibitors of p38 kinase and JNK, respectively, enhanced its inhibitory effect on the expression of MMPs in IL-1β treated chondrocytes. Taken together, these results suggest that Avn-C is an effective candidate to prevent OA progression and a natural health product to relieve OA pathogenesis.

• Journal of Ginseng Research
• /
• v.45 no.4
• /
• pp.510-518
• /
• 2021

Background: Gintonin is a newly derived glycolipoprotein from the roots of ginseng. The purpose of this study is to investigate the anti-arthritic efficacy of Gintonin on various proteases and inflammatory mediators that have an important role in arthritis. Methods: Fibroblast-like synoviocytes (FLS) were treated with Gintonin and stimulated with interleukin (IL)-1β 1 hour later. The antioxidant effect of Gintonin was measured using MitoSOX and H₂DCFDA experiments. The anti-arthritic efficacy of Gintonin was examined by analyzing the expression levels of inflammatory mediators using RT-PCR, western blot, and ELISA. The phosphorylation of mitogen-activated protein kinase (MAPK) pathways and translocation of nuclear factor kappa B (NF-κB)/p65 into the nucleus were also analyzed using western blot, ELISA, and immunocytochemistry. Collagen-induced arthritis (CIA) mice model was used. Mice were orally administered with Gintonin (25, 50, and 100 mg/kg) every 2 days for 45 days. The body weight, arthritis score, squeaking score, and paw volume were measured as the behavioral parameters. After sacrifice, H&E and safranin-O staining were performed for histological analysis. Results: Gintonin significantly inhibited the expression of inflammatory intermediates. Gintonin prevented NF-κB/p65 from moving into the nucleus through the JNK and ERK MAPK phosphorylation in FLS cells. Moreover, Gintonin suppressed the symptoms of arthritis in the CIA mice model. Conclusion: As a result, the antioxidant and anti-inflammatory effects of Gintonin were demonstrated, and ultimately the anti-arthritic effect was proved. Collectively, Gintonin has a great potential as a therapeutic agent for arthritis treatment.

• Journal of Animal Reproduction and Biotechnology
• /
• v.38 no.3
• /
• pp.109-120
• /
• 2023

Background: Pluripotent stem cells (PSCs) including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) offer the immense therapeutic potential in stem cell-based therapy of degenerative disorders. However, clinical trials of human ESCs cause heavy ethical concerns. With the derivation of iPSCs established by reprogramming from adult somatic cells through the transgenic expression of transcription factors, this problems would be able to overcome. In the present study, we tried to differentiate porcine iPSCs (piPSCs) into endothelial cells (ECs) for stem cell-based therapy of vascular diseases. Methods: piPSCs (OSKMNL) were induced to differentiation into ECs in four differentiation media (APEL-2, APEL-2 + 50 ng/mL of VEGF, EBM-2, EBM-2 + 50 ng/mL of VEGF) on cultured plates coated with matrigel^® (1:40 dilution with DMEM/F-12 medium) for 8 days. Differentiation efficiency of these cells were exanimated using qRT-PCR, Immunocytochemistry, Western blotting and FACS. Results: As results, expressions of pluripotency-associated markers (OCT-3/4, SOX2 and NANOG) were higher observed in all porcine differentiated cells derived from piPSCs (OSKMNL) cultured in four differentiation media than piPSCs as the control, whereas endothelial-associated marker (CD-31) in the differentiated cells was not expressed. Conclusions: It can be seen that piPSCs (OSKMNL) were not suitable to differentiate into ECs in the four differentiation media unlike porcine epiblast stem cells (pEpiSCs). Therefore, it would be required to establish a suitable PSCs for differentiating into ECs for the treatment of cardiovascular diseases.

• Development and Reproduction
• /
• v.12 no.1
• /
• pp.87-95
• /
• 2008

Neural stem/precursor derived from pluripotent human embryonic stem cells (hESCs) has considerable therapeutic potential due to their ability to generate various neural cells which can be used in cell-replacement therapies for neurodegenerative diseases. However, production of neural cells from hESCs remains technically very difficult. Understanding neural-tube like rosette characteristic neural precursor cells from hESCs may provide useful information to increase the efficiency of hESC neural differentiation. Generally, neural rosettes were derived from differentiating hEBs in attached culture system, however this is time-consuming and complicated. Here, we examined if neural rosettes could be formed in suspension culture system by bypassing attachment requirement. First, we tested whether the size of hESC clumps affected the formation of human embryonic bodies (hEBs) and neural differentiation. We confirmed that hEBs derived from $500{\times}500\;{\mu}m$ square sized hESC clumps were effectively differentiated into neural lineage than those of the other sizes. To induce the rosette formation, regular size hEBs were derived by incubation of hESC clumps($500{\times}500\;{\mu}m$) in EB medium for 1 wk in a suspended condition on low attachment culture dish and further incubated for additional $1{\sim}2$ wks in neuroectodermal sphere(NES)-culture medium. We observed the neural tube-like rosette structure from hEBs after $7{\sim}10$ days of differentiation. Their identity as a neural precursor cells was assessed by measuring their expressions of neural precursor markers(Vimentin, Nestin, MSI1, MSI2, Prominin-1, Pax6, Sox1, N-cadherin, Otx2, and Tuj1) by RT-PCR and immunofluorescence staining. We also confirmed that neural rosettes could be terminally differentiated into mature neural cell types by additional incubation for $2{\sim}6$ wks with NES medium without growth factors. Neuronal(Tuj1, MAP2, GABA) and glial($S100{\beta}$ and GFAP) markers were highly expressed after $2{\sim}3$ and 4 wks of incubation, respectively. Expression of oligodendrocyte markers O1 and CNPase was significantly increased after $5{\sim}6$ wks of incubation. Our results demonstrate that rosette forming neural precursor cells could be successfully derived from suspension culture system and that will not only help us understand the neural differentiation process of hESCs but also simplify the derivation process of neural precursors from hESCs.