• Proceedings of the Korean Biophysical Society Conference
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• 2001.06a
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• pp.64-64
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• 2001

Escherichia coli has developed soxRS regulon to defend against toxicity of superoxide radical. SoxR, superoxide sensor, is oxidized by superoxide-generating agents or nitric oxide and oxidized SoxR activates the transcription of soxS gene. In order to find out the trans-acting factors regulating SoxR activity in vivo, soxS：：lacZ single copy operon fusion construct was prepared and random Tn10 insertional mutatons were performed.(omitted)

• Journal of Life Science
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• v.7 no.3
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• pp.180-185
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• 1997

Methylelaiophylin generated superoxide radicals in Bacillus subtilis and showed antibacterial activity against a broad range of gram positive bacteria. The inhibition of DNA synthesis was more sensitive than one of RNA synthesis. A recombination-deficient mutant strain of B. subtilis was 2-fold more sensitive than a wild strain, and this sensitivity was reduced in the presence of an antioxidant, dithiothreitol. Methylelaiophylin generated superoxide radicals in B. subtilis lysates, and this suggests that the antibacterial activity of methylelaiophylin is related to the generation of active oxygen species in the cells.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2410-2412
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• 2010

• Proceedings of the Plant Resources Society of Korea Conference
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• 2000.05a
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• pp.60-61
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• 2000

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.5
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• pp.1494-1504
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• 2004

The present paper reports the effects of Hwaotang an atherosclerosis using a spontaneous experimental model, We have also investigated the pharmacological effect of Hwaotang on collagen- and ADP-induced blood platelet aggregation, thrombin-induced conversion of fibrinogen and fibrinolysis in in vitro experiments, and various effects on stimuli-induced superoxide generation in human neutrophils. Hwao-tang was shown to have inhibitory effect on collagen- and ADP-induced blood platelet aggregation, on thrombin-induced conversion of fibrinogen to fibrin and on the activity of plasminogen or plasmin. Hwao-tang also significantly inhibited fMLP-induced superoxide generation in a concentration-dependent manner, but not that induced by arachidonic acid. Hwao-tang inhibited neutrophil functions, including degranulation, superoxide generation, and leukotriene B4 production, without any effect on 5-lipoxygenase activity. In conclusion, the protection of extracts of Hwao-tang on the ischemic infarction induced artificially might be involved to their inhibition of thrombotic action. The results also indicate that Hwao-tang exerts the effects on superoxide generation related to the inhibition of neutrophil functions.

• Parasites, Hosts and Diseases
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• v.46 no.2
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• pp.95-99
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• 2008

Eosinophil degranulation plays a crucial role in tissue inflammatory reactions associated with helminth parasitic infections and allergic diseases. Paragonimus westermani, a lung fluke causing human paragonimiasis, secretes a large amount of cysteine proteases, which are involved in nutrient uptake, tissue invasion, and modulation of hos's immune responses. There is, however, limited information about the response of eosinophils to direct stimulation by cysteine proteases (CP) secreted by P. westermani. In the present study, we tested whether degranulation and superoxide production from human eosinophils can be induced by stimulation of the 2 CP (27 kDa and 28 kDa) purified from excretory-secretory products (ESP) of P. westermani newly excysted metacercariae (PwNEM). A large quantity of eosinophil-derived neurotoxin (EDN) was detected in the culture supernatant when human eosinophils isolated from the peripheral blood were incubated with the purified 27 kDa CP. Furthermore, the 27 kDa CP induced superoxide anion production by eosinophils in time- and dose-dependent manners. In contrast, the purified 28 kDa CP did not induce superoxide production and degranulation. These findings suggest that the 27 kDa CP secreted by PwNEM induces superoxide production and degranulation of human eosinophils, which may be involved in eosinophil-mediated tissue inflammatory responses during the larval migration in human paragonimiasis.

• Korean Journal of Environmental Biology
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• v.20 no.2
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• pp.173-179
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• 2002

N-nitrosoethylurea (NEU) -induced changes of lipid peroxide content, aldehyde metabolic enzyme activities and antioxidant enzyme activities were examined in cultured rat liver cell. Aldehyde metabolic enzymes tested in this investigation were alcohol dehydrogenase and aldehyde dehydrogenase. Several antioxidant enzymes tested were glutathione transferase, superoxide dismutase, glutathione reductase and catalase. When the cell was exposed with various concentrations of NEU, lipid peroxide content increased about 2.5 fold with 6.25 mM NEU. Maximun 2.3 times higher alcohol dehydrogenase activity was found after NEU treatment. About 2 times higher aldehyde dehydrogenase activity could also be observed. Only slight increases of glutathione transferase and catalase activities occurred with NEU treatment. In addition mnximun 1.5 times higher superoxide dismutase activities and 3 times higher glutathione reductase activities were found after NEU treatment. Therefore, it is likely that the increases of superoxide dismutase and glutathione reductase could contribute in a antioxidative process against NEU toxicity.

• The Korean Journal of Pharmacology
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• v.31 no.3
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• pp.333-344
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• 1995

The effects of adenosine and $N^6-cyclopentyladenosine$ (CPA) on superoxide production, myeloperoxidase release and $Ca^{2+}$ mobilization stimulated by fMLP in neutrophils were investigated. The effects were also observed on the stimulatory actions of C5a and PMA and the responses in lipopolysaccharide-primed neutrophils. In addition, the involvement of cAMP in the inhibitory action of adenosine was examined. The fMLP-stimulated neutrophil respiratory burst, degranulation and intracellular $Ca^{2+}$ mobilization may be regulated by activation of adenosine receptors. Adenosine may not affect the stimulated neutrophil responses due to activation of protein kinase C. fMLP-stimulated respiratory burst in lipopolysaccharide-primed neutrophils may be less sensitive to adenosine, compared with nonprimed cells. The inhibitory effect of theophylline in the presence of adenosine on neutrophil responses appears to be ascribed to accumulation of intracellular cAMP.

• The Korean Journal of Pharmacology
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• v.23 no.1
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• pp.33-44
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• 1987

NADPH oxidase dependent superoxide generation and phagocytosis in neutrophils stimulated with opsonized zymosan or heat aggregated IgG were coincided with the process of calcium uptake. The responses in activated neutrophils were enhanced with increasing concentrations of extracellular calcium and these effects were significantly inhibited by calcium chelators, EGTA and EDTA. The superoxide generation in activated neutrophils was reduced by dantrolene and chlorpromazine. Calcium antagonists, bepredil, diltiazem, verapamil, nifedipine and nimodipine effectively inhibited the calcium uptake, superoxide generation and phagocytosis in activated neutrophils, and NADPH oxidase activity was also inhibited. The results suggest that calcium antagonists may inhibit the superoxide generation and phagocytosis in activted neurtophils by the inhibition of calcium influx and by the action on intracellular redistribution of calcium and NADPH oxidase system.

• Journal of Nutrition and Health
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• v.34 no.7
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• pp.734-740
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• 2001

The purpose of this study was to investigate the effect of green tea catechins on the antioxidative defense enzyme activity of kidney in diabetic rats. Sprague-Dawley male rats weighting 100$\pm$10g were randomly assigned to one normal and three STZ-induced diabetic groups; catechin free diet(DM-0C group), 0.25% catechin diet(DM-0.25C group) and 0.5% catechin diet(DM-0.5C group). Diabetes was induced by intravenous of 55mg/Kg body weight of STZ in sodium citrate buffer(pH 4.3) after 4 weeks feeding of experimental diets. Rats were sacrified at the 6th day of diabetic states. Superoxide dismutase(SOD) activity in kidney was decreased by 25% and 20% in DM-0C and DM-0.25C groups compared with normal group, DM-0.5C group was not significantly different when compared with normal group. Glutathione peroxidase(GSHpx) activity in kidney was were no significant differences the diabetic groups compared to normal group. Xanthin oxidase(XOD) activity was increased by 110% and 63% in DM-0C and DM-0.25C groups compared with normal group, DM-0.5C group was not significantly different when compared with normal group. The contents of superoxide radical(O$_2$)in kindney were 116% and 33%, respectively, higher in DM-0C and DM-0.25C groups than normal group. DM-0.5C group and normal groups were similar levels in their superoxide radical contents of kidneys. Levels of TBARS(thiobarbituric acid reactive substance) in kidney were increased by 62% in DM-0C group, when compared with normal group, but those of DM-0.5C group were similar to that of normal groups. These results indicate that free radical generation system was weakened and free radical scavenger system was enhance in kidney of STZ-induced diabetics rats by dietary catechin. Thereby it may reduce renal disorders such as oxidative damage and aging of tissue.