• Journal of the Korean Ceramic Society
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• v.40 no.6
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• pp.589-593
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• 2003

Silica based Planar Lightwave Circuits (PLC) have been applied to various kinds of wave-guided optical passive devices. SiO$_2$ (buffer) and GeO$_2$-SiO$_2$ (core) thick films have been deposited by Flame Hydrolysis Deposition (FHD). The SiO$_2$ films were produced by the flame hydrolysis reaction of halide materials such as SiCl$_4$, POCl$_3$ and BCl$_3$ into an oxy-hydrogen torch. The P concentration increased from 2.0 to 2.8 at％ on increasing the POCl$_3$/BCl$_3$ flow ratio. The refractive index increased from 1.4584 to 1.4605 on increasing the POC1$_3$/BC1$_3$ flow ratio from 0.6 to 2.6. The refractive index of GeO$_2$-SiO$_2$ films was controlled by the GeCl$_4$ flow rate. The refractive index increased from 1.4615 to 1.4809 on increasing the GeCl$_4$ flow rate from 30 to 120 sccm.

• Journal of Korean Medicine for Obesity Research
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• v.19 no.1
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• pp.1-11
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• 2019

Objectives: The purpose of the present study was to evaluate the preventive effects of ethanol extract of Polygalae radix (EEPR) against oxidative stress (hydrogen peroxide, $H_2O_2$)-induced DNA damage and apoptosis in Chang liver cells. Methods: Chang liver cells were pretreated with various concentrations of EEPR and then challenged with 0.5 mM $H_2O_2$. The cell viability and apoptosis were assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry analysis, respectively. The levels of reactive oxygen species (ROS), mitochondrial membrane potentials (MMPs) and adenosine tri-phosphate (ATP) contents were measured. Expression levels of Bcl-2 and Bax were also determined using Western blot analysis. Results: The results showed that the decreased survival rate induced by $H_2O_2$ could be attributed to the induction of DNA damage and apoptosis accompanied by the increased production of ROS, which was remarkably protected by EEPR. In addition, the loss of $H_2O_2$-induced MMPs and ATP contents was significantly attenuated in the presence of EEPR. The inhibitory effect of EEPR on $H_2O_2$-induced apoptosis was associated with up-regulation of Bcl-2 and down-regulation of Bax, thus reducing the Bax/Bcl-2 ratio. Conclusions: Our data prove that EEPR protects Chang liver cells against $H_2O_2$-induced DNA damage and apoptosis by scavenging ROS and thus suppressing the mitochondrial-dependent apoptosis pathway.

• Journal of Life Science
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• v.23 no.11
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• pp.1342-1350
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• 2013

We examined the effect of hydrogen sulfide ($H_2S$) in chemical hypoxia-induced injury in mouse hepatocytes. Cell viability was significantly decreased by cobalt chloride ($CoCl_2$), a well-known hypoxia mimetic agent in a time- and dose- dependent manner. Sodium hydrosulfide (NaHS, a donor of $H_2S$) pretreatment before exposure to $CoCl_2$ significantly attenuated the $CoCl_2$-induced decrease of cell viability. $CoCl_2$ treatment resulted in an increase of intracellular ROS generation, which is inhibited by NaHS or N-acetyl-cysteine (NAC, a ROS scavenger), and p38 MAPK phosphorylation, which is also blocked by NaHS or NAC. The $CoCl_2$-induced increase of the Bax/Bcl-2 ratio was attenuated by NaHS, NAC, and SB 203580 (p38 MAPK inhibitor). The $CoCl_2$-induced decrease of cell viability was also attenuated by NaHS, NAC, and SB 203580 pretreatment. Additionally, NaHS inhibited the $CoCl_2$-induced COX-2. Similar to the effect of NaHS, NAC blocked $CoCl_2$-induced COX-2 expression. Furthermore, NS-398 (a selective COX-2 inhibitor) attenuated not only the $CoCl_2$-induced increase of the Bax/Bcl-2 ratio, it also decreased cell viability. Taken together, $H_2S$ protects primary cultured mouse hepatocytes against $CoCl_2$-induced cell injury through inhibition of the ROS-activated p38 MAPK cascade and the COX-2 pathway.

• Clinical and Experimental Pediatrics
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• v.48 no.12
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• pp.1378-1384
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• 2005

Purpose : We hypothesized dexrazoxane(DXR) and pentoxifylline(PTX) may prevent myocardial damage in adriamycin(ADR)-induced cardiomyopathic rat model. We also investigated their effects on the myocardial apoptosis and fibrosis in ADR induced cardiomyopathy. Methods : The six-week old female Spregue-Dawley rats were divided into control group(CNT, n=4), ADR group(n=6), ADR+DXR group(DXR, n=5), ADR+PTX group(PTX, n=6), ADR+DXR+PTX group(DXPT, n=5). ADR(5 mg/week, twice) was administrated intravenously to rats except CNT group to induce cardiomyopathy. The PTX(50 mg/kg/day) was administered daily from day-0 to Day-21. The DXR(100 mg/kg) was administered 30 minutes before each ADR injection. On day 21, the rats were sacrificed and the degree of histopathologic changes of hypercontraction band necrosis, cytoplasmic vacuolar change and fibrosis were scored. Immunohistochemical staining for Bcl-2 expression and RT-PCR for $TNF-{\alpha}$ and CTGF were performed. Results : Histopathological scores of myocardial damage were significantly higher in ADR rats than CNT rats(P<0.05), and significantly lower in DXPT rats than ADR rats(P<0.01). Myocardial fibrosis was prevented in both PTX rats and DXPT rats. The expression of Bcl-2 was weaker in ADR rats than that in CNT rats(P<0.05), and stronger in both DXR and DXPT rats than that in ADR rats (P<0.05). $TNF-{\alpha}$ concentration of ADR rats was not different from that of treated groups. Conclusion : DXR prevented myocyte apoptosis with increased Bcl-2 expression, and PTX prevented myocardial fibrosis in ADR induced cardiomyopathic rats. The combination therapy of DXR and PTX showed prevention of cardiomyopathy in ADR induced cardiomyopathy rat model.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.640-646
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• 2005

This study was performed for the investigation of anticancer effects of Siegesbeckia glabrescens(SG) on HepG2 cells, a human hepatoma cell line. In the previous study, we examined the involvement of nitric oxide (NO) on anti-proliferative and apoptotic efficacy of SG in vascular smooth muscle cells. The possible mechanism of the apoptotic effects of SG was investigated in HepG2 cells. SG showed potent cytotoxic activity in HepG2 but not chang cells, liver normal cells. SG treatment caused morphological change such as cell shrinkage, nuclei condensation and cell blebbing in HepG2 cells. SG also increased the nitrite production of HepG2 cells in a dose-dependent manner. Furthermore, L-NNA treatment inhibited the anti-proliferative effect of SG. From RT-PCR, SG decreased Bcl-2 but no affected on Bax. Western blot for procaspase-3 and COX-2 showed that degradation of procaspase-3 protein level or inhibition of COX-2 protein expression by SG treatment. In addition, the apoptotic effect of SG was also demonstrated by DNA laddering. In conclusion, SG-induced HepG2 cells death can occur via apoptosis which was dose-dependent, and associated with apoptosis-related Bcl-2/Bax gene expressions, COX-2 inhibition, caspase-3 activation and NO pathway. These results suggest that SG is potentially useful as a chemotherapeutic/chemopreventive agent in hepatocellular carcinoma.

• Biomedical Science Letters
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• v.23 no.4
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• pp.327-332
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• 2017

A2B adenosine receptor (A2BAR) is known to be a regulator of bone homeostasis, but the regulatory mechanism of A2BAR on the osteoclast proliferation are poorly explored. Recently, we have shown that stimulation with BAY 60-6583, a specific agonist of A2BAR, significantly reduced macrophage-colony stimulating factor (M-CSF)-induced osteoclast proliferation by inducing cell cycle arrest at G1 phase and increasing the apoptosis of osteoclasts. The objective of this study was to investigate the regulatory mechanisms of cell cycle and apoptosis by A2BAR stimulation. The expression of A2BAR and M-CSF receptor, c-Fms, was not changed by A2BAR stimulation whereas M-CSF effectively induced c-Fms expression during osteoclast proliferation. Interestingly, A2BAR stimulation remarkably increased the expression of $p27^{Kip-1}$, a cell cycle inhibitor, but the expression of Cyclin D1 and cdk4 was not affected. In addition, while BAY 60-6583 treatment reduced the expression of Bcl2, an anti-apoptotic oncogene, it failed to regulate the expression of Bax, a pro-apoptotic marker. Taken together, these results imply that the increase of $p27^{Kip-1}$ inducing cell cycle arrest at G1 phase and the decrease of Bcl2 inducing anti-apoptotic response by A2BAR stimulation contribute to the down-regulation of osteoclast proliferation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.95-103
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• 2019

Periodontal inflammation, a major kind of periodontal diseases, is characterized to bleed, pain, and teeth loss, and it is resulted from oxidative stress. Membrane-free stem cell extract could avoid the immunogencity rejection by removal of cell membrane. In the present study, we investigated the protective effect of membrane-free stem cell extract from oxidative stress-induced periodontal inflammation in human periodontal ligament fibroblasts (HPLF). In the cell viability measurement, membrane-free stem cell extract showed significant increase of cell viability, compared with the $H_2O_2$-treated control group. To further investigation of molecular mechanisms, we measured inflammation and apoptosis related protein expressions. Membrane-free stem cell extract attenuated inflammation-related protein expressions such as nuclear factor kappa light chain enhancer of activated B cells, inducible nitric oxide synthase, and interleukin-6. In addition, the treatment of membrane-free stem cell extract decreased apoptotic protein expressions such as cleaved caspase-9, -3, poly (ADP-ribose) polymerase, and B-cell lymphoma 2 (Bcl-2)-associated X protein/Bcl-2 ratio in the $H_2O_2$-treated HPLF cells. In conclusion, membrane-free stem cell extract exhibited anti-oxidative stress effects by regulation of inflammation and apoptosis in HPLF, suggesting that it could be used as the treatment agents for periodontal inflammatory disease.

• Journal of Gastric Cancer
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• v.8 no.3
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• pp.120-128
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• 2008

Purpose: Mistletoe extract was widely used for cancer treatment as complementary or alternative therapy in European area from early twenty century. It is currently used as alternative anti-cancer remedy by piecemeal in domestic medical group, however, the anti-cancer mechanism of mistletoe extract was not known precisely until now. In this study the effect of mistletoe extract on gastric cancer was studied vis cell line experiments. Materials and Methods: The SNU719 gastric cancer cell line was used, and ABNOBAviscum-Q and ABNOBAviscum-F were treated to cells as mistletoe extract, or 5-FU and cisplatin were used with mistletoe extract. The cell viability and cell death rate were estimated by CCK-8 assay kit and lactate dehydrogenase (LDH) assay kit in each. Caspase 3 assay kit was used to measure caspase 3 activity. The protein expression amounts of Bcl2, p53, and PTEN were estimated through Western blot analysis. Results: The co-treatments of mistletoe extract Q/F and 5-FU/cisplatin decreased lesser cell viability than only mistletoe treat. Caspase 3 activity was increased 4~6 times in co-treatment of mistletoe extracts and 5-FU than control. Bcl2 protein expression was reduced by mistletoe extracts or anti-cancer drugs, further more, the co-treatment of mistletoe extracts and 5-FU/cisplatin diminished more the expression than only mistletoe treatment. Mistletoe extracts did not affect the protein expressions of p53 and PTEN. Conclusion: It was concluded that the anti-cancer mechanism of mistletoe extracts was made by caspase 3 activation and lowered Bcl2 expression, and this apoptosis inducing mechanism was independent to p53.

• Proceedings of the Korea Contents Association Conference
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• 2014.06a
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• pp.233-234
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• 2014

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.10a
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• pp.3-8
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• 1995