• Development and Reproduction
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• v.12 no.1
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• pp.1-8
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• 2008

Specific protocols to increase the differentiation of neuronal cells from embryonic stem (ES) cells have been well established, such as retinoic acid induction and lineage selection of neuronal cells. For the neuropathological studies, ES-derived neurons (ES neurons) must show normal physiological characteristics related to cell death and survival and should be maintained in vitro for a sufficient time to show insults-specific cell death without spontaneous death. When mouse ES cells were plated onto astrocytes monolayer after retinoic acid induction, most ES cells differentiated into neuronal cells, which were confirmed by the presence of specific neuronal markers, and the cultures were viable for at least four weeks. When these cultures were examined for vulnerability to glutamate excitotoxicity, ES neurons were vulnerable to excitotoxic insults mediated by agonist-specific receptors. The vulnerability to excitotoxic death increased with developmental age of ES neurons in vitro. Specific receptors for Neurotrophin and GDNF family ligands were present in ES neurons. GDNF and NT-3 could modulate the survival and excitotoxic vulnerability of ES neurons. The vulnerability and resistance to toxic insults, which are essential requirements of model culture systems for neuropathological studies, make ES neurons to a useful model culture system. Especially ES cell are highly amenable to genetic modification unlikely to primary neuronal cells, which will give us a chance to answer more complicated neurophysiological questions. Recently there was an outstanding attempt to explore the cellular toxicity using human ES cells (Schrattenholz & Klemm, 2007) and it suggested that ES cells could be a new model system for neurophysiological studies soon and go further a large-scale screening system for pharmacological compounds in the future.

• Development and Reproduction
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• v.14 no.2
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• pp.99-105
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• 2010

The seminiferous epithelium, with its division into 12 spermatogenic stages in the mouse, is a very complex tissue. Glutathione peroxidase (GPx) is a representative antioxidant enzyme that is capable of reducing organic hydroperoxides to their corresponding hydroxyl compounds utilizing glutathione and is related to the mammalian spermatogenesis. In this study, a real-time PCR was performed in the stage-specific seminiferous tubules of mouse testes excised by a laser capture microdissection (LCM) in order to quantitate the expression levels of a series of GPx genes including cytosolic GPx (cGPx), gastrointestinal GPx (GI-GPx), plasma GPx (pGPx), and phospholipid hydroperoxide GPx (PHGPx). Frozen sections (10 ${\mu}m$) were obtained from normal adult mouse testes. LCM was used to capture all the cells that were grouped into stages I-V, VII-VIII, and IX-XI in cross-sections of seminiferous tubules. The expression level of PHGPx mRNA was remarkably higher than those of other GPx mRNAs in mouse testes. During spermatogenesis, the expressions of GI-GPx, pGPx, and PHGPx mRNAs were highest on stages VII-VIII, began to decrease after stage XI, and showed a lowest level on stage I-V. However, the expressions of cGPx mRNA were highest on stages VII-VIII, and showed a lowest level on stage XI-XI. These findings indicate that GPx genes are expressed differentially on mouse spermatogenesis and also LCM can be an useful tool in cellular quantitative analysis of testes.

• Microbiology and Biotechnology Letters
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• v.46 no.1
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• pp.18-28
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• 2018

In this study, the antioxidant activities and cytoprotective effects against oxidative stress of Lonicera japonica Thunb. 50% ethanol extract and ethyl acetate fraction were investigated. Using the 1,1-diphenyl-2-picrylhydrazyl assay, the free radical scavenging activity (FSC50) of L. japonica Thunb. 50% ethanol extract and ethyl acetate fraction was determined as 152.00 and $77.25{\mu}g/ml$, respectively. To measure the reactive oxygen species (ROS) scavenging activity, the total antioxidant capacity (OSC50) was determined by using a luminol-dependent chemiluminescence assay. The antioxidant activity of the ethyl acetate fraction ($0.33{\mu}g/ml$) was approximately four times stronger than that of the 50% ethanol extract ($1.12{\mu}g/ml$). The protective effect against $^1O_2$-induced cellular damage of human erythrocytes (${\tau}_{50}$) was 46.0 min at $10{\mu}g/ml$ of the 50% ethanol extract and 52.3 min at $1{\mu}g/ml$ of the ethyl acetate fraction. We also investigated the cytoprotective effects against oxidative stress induced by $H_2O_2$ and the intracellular ROS scavenging activity in response to UVB irradiation and found that the extract and fraction protected human skin cells from damage and reduced ROS. These results confirmed that L. japonica Thunb. was a valuable plant-derived natural antioxidant with potential for development as an antioxidative functional ingredient.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.2
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• pp.203-213
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• 2018

Tumor undergo uncontrolled, excessive proliferation leads to hypoxic microenvironment. To fulfill their demand for nutrient, and oxygen, tumor angiogenesis is required. Endothelial progenitor cells (EPCs) have been known to the main source of angiogenesis because of their potential to differentiation into endothelial cells. Therefore, understanding the mechanism of EPC-mediated angiogenesis in hypoxia is critical for development of cancer therapy. Recently, mitochondrial dynamics has emerged as a critical mechanism for cellular function and differentiation under hypoxic conditions. However, the role of mitochondrial dynamics in hypoxia-induced angiogenesis remains to be elucidated. In this study, we demonstrated that hypoxia-induced mitochondrial fission accelerates EPCs bioactivities. We first investigated the effect of hypoxia on EPC-mediated angiogenesis. Cell migration, invasion, and tube formation was significantly increased under hypoxic conditions; expression of EPC surface markers was unchanged. And mitochondrial fission was induced by hypoxia time-dependent manner. We found that hypoxia-induced mitochondrial fission was triggered by dynamin-related protein Drp1, specifically, phosphorylated DRP1 at Ser637, a suppression marker for mitochondrial fission, was impaired in hypoxia time-dependent manner. To confirm the role of DRP1 in EPC-mediated angiogenesis, we analyzed cell bioactivities using Mdivi-1, a selective DRP1 inhibitor, and DRP1 siRNA. DRP1 silencing or Mdivi-1 treatment dramatically reduced cell migration, invasion, and tube formation in EPCs, but the expression of EPC surface markers was unchanged. In conclusion, we uncovered a novel role of mitochondrial fission in hypoxia-induced angiogenesis. Therefore, we suggest that specific modulation of DRP1-mediated mitochondrial dynamics may be a potential therapeutic strategy in EPC-mediated tumor angiogenesis.

• The korean journal of orthodontics
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• v.28 no.4 s.69
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• pp.611-626
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• 1998

Cytokines are intercellular peptide mediators that regulate homeostasis and host defense reactions in living body. Of the diversity of cytokines in terms of biological accomplishment, interleukin $1-{\beta}$($IL-1{\beta}$) and tumor necrosis factor(TNF) are the most conspicuous cytokines with a wide variety of effects on cells involved in inflammatory and immune responses, and likely to be involved in the inflammatory pathogenesis of oral tissue as well. The present study was designed to explicate the role of $IL-1{\beta}$ on inflammatory revelation of oral tissues in mice biochemically. In the Induced arthritis by injection of 10${\mu}g$ LPS shown the relaese of 0.93 ${\mu}g$ $IL-1{\beta}$/joint with a peak at at 4-5 h. and diminished at 24t and the release of $TNF_{\alpha}$ of 1.25 ${\mu}g$/joint with a peak at 2-3h and diminished at 6h. After injection of th $IL-1{\beta}$ into the joint, the mumber of leucocytes proliferated with a peak at 4-5h and diminished at 36h and the loss of proteoglycan showed with maximum at 15-30h. After injection of $IL-1{\beta}$ into the oral tissue, cycloosygenase metabolites ($PGE_2$) accumulated in the oral tissue with dose dependant. These elucidated $IL-1{\beta}$ to be inflammatory mediator in the early phase of its pathogenesis. Intraoral injection of recombinant $IL-1{\beta}$ induced the proliferation of leukocytes in situ. $IL-1{\beta}$ took an pertinent part in the development of inflammation and the succession of cellular infiltration. The results exemplify that $IL-1{\beta}$ plays a significant role in mediating inflammatory response induced by LPS in oral tissue, the inflammatory response is regulated by $IL-1{\beta}$ at an acute phase of pathogenesis.

• Tuberculosis and Respiratory Diseases
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• v.69 no.1
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• pp.16-23
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• 2010

Background: Most lung cancer patients receive systemic chemotherapy at an advanced stage disease. Cisplatin-based chemotherapy is the main regimen for treating advanced lung cancer. Recently, autophagy has become an important mechanism of cellular adaptation under starvation or cell oxidative stress. The purpose of this study was to determine whether or not autophagy can occurred in cisplatin-treated lung cancer cells. Methods: H460 cells were incubated with RPMI 1640 and treated in $5{\mu}M$ or $20{\mu}M$ cisplatin concentrations at specific time intervals. Cells surviving cisplatin treatment were measured and compared using an MTT cell viability assay to cells that underwent apoptosis with autophagy by nuclear staining, apoptotic or autophagic related proteins, and autophagic vacuoles. The development of acidic vascular organelles was using acridine orange staining and fluorescent expression of GFP-LC3 protein in its transfected cells was observed to evaluate autophagy. Results: Lung cancer cells treated with $5{\mu}M$ cisplatin-treated were less sensitive to cell death than $20{\mu}M$ cisplatin-treated cells in a time-dependent manner. Nuclear fragmentation at $5{\mu}M$ was not detected, even though it was discovered at $20{\mu}M$. Poly (ADP-ribose) polymerase cleavages were not detected in $5{\mu}M$ within 24 hours. Massive vacuolization in the cytoplasm of $5{\mu}M$ treated cells were observed. Acridine orange stain-positive cells was increased according in time-dependence manner. The autophagosome-incorporated LC3 II protein expression was increased in $5{\mu}M$ treated cells, but was not detected in $20{\mu}M$ treated cells. The expression of GFP-LC3 were increased in $5{\mu}M$ treated cells in a time-dependent manner. Conclusion: The induction of autophagy occurred in $5{\mu}M$ dose of cisplatin-treated lung cancer cells.

• Tuberculosis and Respiratory Diseases
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• v.46 no.2
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• pp.229-240
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• 1999

Background: The impact of the immune response on cancer gene therapy using viral vectors to deliver a "suicide gene" is currently unclear. A vigrous immune response targeted at viral proteins or transgene may enhance the efficacy of tumor destruction and even augment responses to tumor antigens. These responses may involve the release of cytokines and stimulation of tumor specific cytotoxic T-lymphocytes that enhance therapeutic efficacy. On the other hand, a vigorous rapid cellular immune response may destroy cells expressing the therapeutic gene and attenuate the response to therapy. Furthermore, development of neutralizing antibody responses may prevent readministration of virus, a potentially significant limitation. Evaluating the significance of these limitations in animal models and developing solutions are therefore of obvious importance. Methods: After retroviral transduction of mouse mesothelioma cell line(AB12) with Herpes Simplex Virus thymidine kinase (HSVtk) gene in vitro, subcutaneous flank tumors were established. To study the effect of intact immune system on efficacy of tumor erradication, the ability of the HSVtk/ganciclovir system to inhibit tumor growth was compared among normal Balb/c mice, immunodeficient Balb/c-nude and SCID mice, and Balb/c mice immunosuppressed with cyclosporin. Results: Ganciclovir treatment resulted in greater inhibition of tumor growth in Balb/c mice compared with immunodeficient Balb/c-nude mice and SCID mice(in immunodeficient mice, there were no growth inhibition by ganciclovir treatment). Ganciclovir treatment resulted in greater inhibition of tumor growth in noncyclosporin (CSA) treated Balb/c mice compared with CSA treated Balb/c mice. On day 8, mean ganciclovir-treated tumor volume were 65% of control tumor volume in Balb/c mice versus 77% control tumor volume in CSA-treated Balb/c mice. This effect was still evident during therapy (day 11 and 13). On day 13, non-CSA treated tumor volume was 35% of control tumor volume versus 60% of control tumor volume in CSA treated Balb/c mice. Duration of expression of HSVtk was not affected by the immunosuppression with CSA. Conclusion: These results indicate that the immune responses against retrovirally transduced cells enhance the efficacy of the HSVtk/ganciclovir system. These findings have important implications for clinical trials using currently available retrovirus vectors as well as for future vector design.

• Molecules and Cells
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• v.38 no.3
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• pp.210-220
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• 2015

Athletic performance is an important criteria used for the selection of superior horses. However, little is known about exercise-related epigenetic processes in the horse. DNA methylation is a key mechanism for regulating gene expression in response to environmental changes. We carried out comparative genomic analysis of genome-wide DNA methylation profiles in the blood samples of two different thoroughbred horses before and after exercise by methylated-DNA immunoprecipitation sequencing (MeDIP-Seq). Differentially methylated regions (DMRs) in the pre-and post-exercise blood samples of superior and inferior horses were identified. Exercise altered the methylation patterns. After 30 min of exercise, 596 genes were hypomethy-lated and 715 genes were hypermethylated in the superior horse, whereas in the inferior horse, 868 genes were hypomethylated and 794 genes were hypermethylated. These genes were analyzed based on gene ontology (GO) annotations and the exercise-related pathway patterns in the two horses were compared. After exercise, gene regions related to cell division and adhesion were hypermethylated in the superior horse, whereas regions related to cell signaling and transport were hypermethylated in the inferior horse. Analysis of the distribution of methylated CpG islands confirmed the hypomethylation in the gene-body methylation regions after exercise. The methylation patterns of transposable elements also changed after exercise. Long interspersed nuclear elements (LINEs) showed abundance of DMRs. Collectively, our results serve as a basis to study exercise-based reprogramming of epigenetic traits.

• Clinical and Experimental Reproductive Medicine
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• v.36 no.1
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• pp.23-34
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• 2009

Objectives: Mesenchymal stem cells (MSC) comprise a promising tool for cellular therapy. It is known that long-term in vitro culture of human bone marrow and adipose tissue derived-MSCs lead to a reduction of life span and a change of stem-like characters. The aim of our study was to examine whether stem cell properties of human umbilical cord-derived stem cells (HUC) could be affected by in vitro expansion. Methods: HUC were isolated from human umbilical cord and cultured for 10 passages in vitro. Morphology and population doubling time (PDT) were investigated, and changes of stem cell properties were examined using RT-PCR and immunocytochemistry during serial subcultures. Results: Morphology and PDT of HUC began to change slightly from the 7th passage (p7). Expression level of nestin and vimentin mRNAs increased along with the culture period from p4 until p10. In contrast, expression level of SCF mRNA decreased during the same culture period. Expression level of Oct-4 and HNF-4${\alpha}$ mRNAs was not significantly changed throughout the culture period until p10. Expression level of BMP-4, FGF-5, NCAM and HLA-ABC mRNAs appeared to increase as the culture continued, however, the difference was not significant. Immunocytochemical studies showed that HUC at p3, p6 and p9 positively were stained with antibodies against SSEA-3 and SSEA-4 proteins. Interestingly, staining intensity of HUC for ICAM-1 and HLA-ABC gradually increased throughout the culture period. Intensity against thy-1 and fibronectin antibodies increased at p9 while that against TRA-1-60 and VCAM-1 antibodies began to decrease at p6 until p9. Conclusions: These results suggest that HUC change some of their stem cell characteristics during in vitro culture. Development of culture system might be needed for the maintenance of characteristics.

• Journal of Yeungnam Medical Science
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• v.16 no.2
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• pp.228-236
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• 1999

Background: Thyrotoxic periodic paralysis is an uncommon illness characterized by intermittent flaccid paralysis of skeletal muscle, usually accompanied by hypokalemia, in patient with hyperthyroidism. However, the pathophysiology of thyrotoxic periodic paralysis remains largely unexplained and controversial. This report describes the clinical and biochemical findings in 19 patients with thyrotoxic periodic paralysis who were examined at the Yeungnam University Medical Center(YUMC) during the past decade. Methods: The medical records of 997 YUMC patients, seen between 1986 and 1996, with diagnosis of hyperthyroidism were reviewed. Nineteen patients out of 997 hyperthyroidism patients were diagnosed, and examined by history, physical examination, serum electrolyte value, and thyroid function test during paralysis. On the basis of these results, comparisons were made on age, sex, precipitating factors, timing, affected limbs, prognosis, serum potassium and serum phosphate and thyroid hormone levels. Results: The prevalence of periodic paralysis in hyperthyroidism was 1.9 percent and the male to female prevalence ratio was 30:1 and in all patients, the development of perodic paralysis was correlated with hyperfunctional state of the thyroid gland. Eleven cases of periodic paralysis were associated with hypokalemia and their thyroid hormone levels were significantly more increased than those of the patients without hypokalemia. Interestingly, our study shows the recurrence of paralysis after treatment. Conclusion: Although the precise pathophysiology of the disease is as yet undefined and controversial, it occurs primarily in Asians with an overwhelming male preponderance and prevalence of 2 percent in hyperthyroidism. The interactive roles of thyroid hormone, Na-K pump, and genetically inherited defect in the cellular membrane potential of the skeletal muscle can be speculated. Further investigation will be needed to firmly establish the mechanism of thyrotoxic periodic paralysis.