• Parasites, Hosts and Diseases
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• v.49 no.1
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• pp.1-8
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• 2011

The pathogenesis and pathophysiology of Acanthamoeba infections remain incompletely understood. Phospholipases are known to cleave phospholipids, suggesting their possible involvement in the host cell plasma membrane disruption leading to host cell penetration and lysis. The aims of the present study were to determine phospholipase activities in Acanthamoeba and to determine their roles in the pathogenesis of Acanthamoeba. Using an encephalitis isolate (T1 genotype), a keratitis isolate (T4 genotype), and an environmental isolate (T7 genotype), we demonstrated that Acanthamoeba exhibited phospholipase $A_2$ (PLA$_2$). and phospholipase D (PLD) activities in a spectrophotometry-based assay. Interestingly, the encephalitis isolates of Acanthamoeba exhibited higher phospholipase activities as compared with the keratitis isolates, but the environmental isolates exhibited the highest phospholipase activities. Moreover, Acanthamoeba isolates exhibited higher PLD activities compared with the PLA$_2$. Acanthamoeba exhibited optimal phospholipase activities at $37^{\circ}C$ and at neutral pH indicating their physiological relevance. The functional role of phospholipases was determined by in vitro assays using human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. We observed that a PLD-specific inhibitor, i.e., compound 48/80, partially inhibited Acanthamoeba encephalitis isolate cytotoxicity of the host cells, while PLA$_2$-specific inhibitor, i.e., cytidine 5'-diphosphocholine, had no effect on parasite-mediated HBMEC cytotoxicity. Overall, the T7 exhibited higher phospholipase activities as compared to the T4. In contract, the T7 exhibited minimal binding to, or cytotoxicity of, HBMEC.

• Archives of Pharmacal Research
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• v.18 no.4
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• pp.267-270
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• 1995

We examined the chronic effect of dextromethorphan(DM) on the cellular immune responses in mice. T cell simulator, phytohemagglutinin did not show singificant effect on lymphocyte proliferation. Costimulator of T and B cell, pokeweed mitogen, and B cell stimulator, lipopolysaccharide exhibited DM-induced decreased lymphocyte proliferation. Singificantly suppressed natural killer (NR) cell cytotoxicity was evidenced following 6 months DM exposure. These results suggest that chronic DM administration pertub B cell functioning and NK cell cytotoxicity. In addition, prenatal DM exposure did not potentiate the immunomodulation in postnatal effect induced by chronic DM.

• Journal of the Korean Society of Tobacco Science
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• v.25 no.2
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• pp.128-136
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• 2003

Although tobacco smoke has been known to have genotoxicity as well as cytotoxicity, the sensitivity of the cell lines used against cigarette smoke is poorly understood. The objective of this study was to evaluate and compare the genotoxicity of several cell lines, which are routinely used in the in vitro assays, with cigarette smoke condensate(CSC) of Kentucky Reference Cigarette 1R4F. In the micronucleus(MN) induction assays, murine(CHO-K1, V79, BALB/c 3T3) cell lines and human(MCF-7, A549) ones were used. As a result, the CSC exhibited cytotoxicity with a concentration-dependent response in all cell lines. EC$_{50}$ of CSC in CHO-K1, V79, BALB/c 3T3, MCF-7 and A549 were 140, 125, 100, 116 and 109 $\mu\textrm{g}$/mL, respectively. On the other hand, the spontaneous micronucleated cell(MNC) frequency was stable and reproducible in every cell lines tested in this study. The dose-response of various cell lines to the induction of MN by CSC was estimated using linear regression analysis. CSC(0～100 $\mu\textrm{g}$/mL) caused a dose-dependent MN induction in CHO-K1, V79, BALB/c 3T3 and MCF-7 cell lines. Putting together all the data obtained and linear regression analysis of the data, we concluded that V79 cells are more susceptible to the accurate assessment of CSC-induced MN than the others.s.

• Animal cells and systems
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• v.8 no.2
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• pp.125-133
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• 2004

We have extended our previous work that cross-linking CD4 molecules using specific MAb induced antigen nonspecific, MHC unrestricted killing of virally infected target cells by CD$4^+$We have extended our previous work that cross-linking CD$4^+$ molecules using specific MAb induced antigen nonspecific, MHC unrestricted killing of virally infected target cells by CD$4^+$ T cells. The killing activity of antibody activated CD$4^+$T cells was completely blocked by herbimycin A, a protein tyrosine kinase (PTK) inhibitor, but not by bisindolylamaleimide, a protein kinase C (PKC) inhibitor. Herbimycin A treated human or bovine peripheral blood CD$4^+$T cells lacked PTK activity and failed to kill virally infected target cells even after cross-linking of CD4 molecules. The CD$4^+$cross-linking failed to induce effector cell proliferation or the transcription of TNF${\beta}$ Upregulation of TNF${\beta}$ was induced by incubating the antibody activated effector cells with BHV-1 infected D17 target cells for 10 h. Anti-TNF${\beta}$ antibody partially abolished (13-44%) the direct effector cell-mediated antiviral cytotoxicity. However, this antibody neutralized 70 to 100% of antiviral activity of effector and target cell culture supernatants against BHV-1 infected D17 cells. The inhibition level of the antiviral activity by the antibody was dependent on the effector and target cell ratio. These results support the hypothesis that increased p$56^ICK enzyme activity in effector cells transduces a signal critical for effector cell recognition of viral glycoproteins expressed on the target cells. Following target cell recognition, lytic cytokines known to participate in target cell killing were produced. A better understanding of the killing activity displayed by CD$4^+$T lymphocytes following surface receptor cross-linking will provide insight into the mechanisms of cytotoxic activity directed toward virally-infected cells.T cells. The killing activity of antibody activated CD$4^+$T cells was completely blocked by herbimycin A, a protein tyrosine kinase (PTK) inhibitor, but not by bisindolylamaleimide, a protein kinase C (PKC) inhibitor. Herbimycin A treated human or bovine peripheral blood CD4T cells lacked PTK activity and failed to kill virally infected target cells even after cross-linking of CD4molecules. The CD4 cross-linking failed to induce effector cell proliferation or the transcription of TNF$\beta$. Upregulation of TNF$\beta$ was induced by incubating the antibody activated effector cells with BHV-1 infected D17 target cells for 10 h. Anti-TNF$\beta$ antibody partially abolished (13-44%) the direct effector cell-mediated antiviral cytotoxicity. However, this antibody neutralized 70 to 100% of antiviral activity of effector and target cell culture supernatants against BHV-1 infected D17 cells. The inhibition level of the antiviral activity by the antibody was dependent on the effector and target cell ratio. These results support the hypothesis that increased $56^ICK enzyme activity in effector cells transduces a signal critical for effector cell recognition of viral glycoproteins expressed on the target cells. Following target cell recognition, lytic cytokines known to participate in target cell killing were produced. A better understanding of the killing activity displayed by CD$4^+$T lymphocytes following surface receptor cross-linking will provide insight into the mechanisms of cytotoxic activity directed toward virally-infected cells.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.5
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• pp.1304-1308
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• 2008

This study was performed to evaluate the effect of persimmon leaves extract on the reactive oxygen species (ROS) in cultured melanoma cells. The B16/F10 melanoma cells were treated with various concentrations of t-butyl hydroperoxide (t-BHP). And also, the effect of persimmon leaves (PL) extract on the cytotoxicity mediated by t-BHP was done on the cell viability, tyrosinase activity and melanogenesis by colorimetric assays. In this study, t-BHP decreased cell viability in dose-dependent manner and XTT90 and XTT50 values were measured at 10 and 35 uM of PL, respectively in these culture. And also, XTT50 value was assessed as a highly toxic effect on cultured melanoma cells by the toxic criteria. In the effect of PL extract on the t-BHP-mediated cytotoxicity, PL extract significantly increased the cell viability injured by t-BHP in cultured B16/F10 melanoma cells. PL also showed the decreased tyrosinase activity and melanogenesis. From these results, it is suggested that ROS such as t-BHP showed highly toxic effect on cultured melanoma cells, and also, PL extract inhibited the tyrosinase activity and melanogenesis in cultured melanoma cells injured by ROS.

• Journal of Convergence for Information Technology
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• v.11 no.8
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• pp.201-206
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• 2021

The aim of this study was to examined the dermatoxicity of ferrous chloride (FeCl2) and the antioxidative effect of Stachys japonica Miq (SJ) extract on FeCl2-induced cytotoxicity. For this study, superoxide anion-radical (SAR)-scavenging and superoxide dismutase (SOD)-like abilities with cell viability were done. FeCl2 showed a significant decrease of cell viability in dose-dependent manner, and it was mid-toxic. The caffeic acid showed a significant increase of cell viability against FeCl2-induced cytotoxicity. In the protective effect of SJ extract on FeCl2-induced cytotoxicity, it showed SAR-scavenging and SOD-like abilities with a significant increase of cell viability. From these results, the cytotoxicity of FeCl2 is correlated with oxidative stress, and SJ extract effectively protected the cytotoxicity of FeCl2 by antioxidative effect. Conclusively, the natural resources like SJ extract may be a useful fundamental materials for the development of an alternative antioxidant.

• Biomedical Science Letters
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• v.25 no.4
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• pp.348-356
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• 2019

This study evaluated the dermal cytotoxicity of sodium bromate (NaBrO₃) and the protective effect of Aster tataricus L. (AT) extract against NaBrO₃-induced cytotoxicity in the cultured NIH3T3 fibroblasts. For this study, it was done the antioxidative effects such as electron donating (ED) activity and lipid peroxidation (LP) activity as well as cell viability. NaBrO₃ significantly decreased cell viability in a dose-dependent manner and its XTT₅₀ value was measured at a concentration of 54.4 μM in these cultures. The cytotoxicity of NaBrO₃ was determined as highly-toxic by Borenfreund and Puerner's toxic criteria. The quercetin, antioxidant significantly increased cell viability against NaBrO₃-induced cytotoxicity. Regarding the protective effect of Aster tataricus (AT) L. extract on NaBrO₃-induced cytotoxicity, AT extract significantly increased the cell viability, the ED ability and the inhibitory ability of LP. From these findings, it suggested that the oxidative stress is involved in the cytotoxicity of NaBrO₃, and AT extract effectively protected NaBrO₃-induced cytotoxicity by antioxidative effects. Conclusively, the natural component like AT extract may be a putative therapeutic agent for the diminution or treatment of the cytotoxicity correlated with oxidative stress like hair dye component, NaBrO₃.

• Journal of Pharmacopuncture
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• v.10 no.1 s.22
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• pp.121-135
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• 2007

Objectives : This study was carried out to examine protective effect of wild ginseng extract on HepG2 human hepatoma cell line against tert-Butyl hydroperoxide (t-BHP)-induced oxidative damage. Methods : To evaluate protective effect of wild ginseng extract against t-BHP induced cytotoxicity, LDH level and activity of glutathione peroxidase and reductase were measured. Gene expression was also measured using DNA microarray. Results : Wild ginseng extract showed a significant protective effect against t-BHP-induced cytotoxicity in HepG2 cell line. It is not, however, related with the activities of glutathione peroxidase and glutathione reductase. Analysis of gene expression using DNA chip, demonstrated that 28 genes were up-regulated in t-BHP only group. Five genes - selenoprotein P, glutathione peroxidase 3, sirtuin 2, peroxiredoxin 2, serfiredoxin 1 homolog - may be related with the protective effect of wild ginseng extract. Conclusions : Based on the results, a protective effect of wild ginseng extract against t-BHP-induced oxidative damage in HepG2 cell line is not associated with the activities of glutathione peroxidase and glutathione reductase, but with the expression of selenoprotein P, glutathione peroxidase 3, sirtuin 2, peroxiredoxin 2, and serfiredoxin 1 homolog.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.19 no.1
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• pp.55-64
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• 2006

Objective : The purpose of this study was to investigate effect of Gungguitakli-San(GTS) on the anti-tumor, immunocytes. Methods : This study estimated the proliferation of L1210 and S-180 cell lines, mouse splenocytes and thymocytes in vitro, and estimated the proliferation of L1210 cell, S-180 cell, thymocytes and splenocytes and body weight in S-180 cells-transplanted mice. The cytotoxicity and proliferation of cells were tested using a colorimetric tetrazoliun assay(M1T assay). Results : The results of this study were obtained as follow ; 1. GTS was significantly increased in the proliferation of thymocytes and splenocytes In vitro. 2. GTS was significantly showed cytotoxicity on the L1210 cell lines and 8-180 cell lines in vitro. 3. GTS was significantly showed cytotoxicity on the L1210 cell lines in vivo. 4. GTS was significantly increased in the weight of mice and decreased weight of sarcoma, in S-180 cells transplanted mice. 5. GTS was significantly increased in the period of survive, in S-180 cells transplanted mice. Conclusions : The author thought that GTS had action of anti-cancer by becoming immunocytes activity and by cytotoxicity of cancer cells.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.9 no.1
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• pp.1-15
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• 1996

The purpose of this research was to investigate effect of water extract of DangKwi-Eum-Ja ka Sumsoo(DESE) on the cytotoxicity of human epidemloid cell, A431 cells. The effects of DESE on the proliferation of A431 cells, Balb/c 3T3 cells, mouse thymocytes and splenocnes were estimated by MTT colorimetric assay, and nitric oxide production from mouse peritoneal macrophage was estimated by Griess method. DESE inhibited the proliferation of A431 cells at $10{\mu}g/ml$, and did not affect the proliferation of Balb/c 3T3 cells. DESE decreased the cytotoxicity of mitomycin C or cisplatin on A431 cells, increased the cytotoxicity of mitomycin C or cisplatin on Balb/c 3T3 cells. DESE inhibited the proliferation of mouse thymocytes and splenocytes at $100{\mu}g/ml$. DESE did not affect the nitric oxide production from mouse peritoneal macrophage in vitro, but decreased the nitric oxide production from DESE-treated mouse peritoneal macrophage.