• Environmental Analysis Health and Toxicology
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• v.23 no.1
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• pp.33-39
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• 2008

The genotoxicity of mercury compounds have been investigated with a variety of genetic endpoints in prokaryotic and eukaryotic cells. The mercury ions are positively charged and easily form complexes with DNA by binding with negatively charged centers to cause mutagenesis. Further, the mercury ions can react with sulfhydryl (-SH) groups of proteins associated with DNA replication and alter genetic information. Another mechanism by which mercury damages DNA molecule is via its probable involvement of reactive oxygen species (ROS) and induces DNA strand breaks. In order to investigate whether the ROS production was induced by mercury, we performed ROS assay. As the result, the ROS production was significantly increased when it grows dose-dependently and time-dependently. We compared mercury alone-treated group and mercury co-treated with Vitamin C or glutathione group. As the result, the ROS production induced by mercury was decreased by Vitamin C and glutathione. Co-treated with Vitamin C and glutathione group was the most effective to lowering ROS production induced by mercury.

• 대한생식의학회:학술대회논문집
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• 2000.06a
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• pp.29-35
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• 2000

The imbalance between reactive oxygen species (ROS) production and total antioxidant capacity (TAC) in seminal fluid indicates oxidative stress and is correlated with male infertility. A composite ROS-TAC score may be more strongly correlated with infertility than ROS or TAC alone. We measured ROS, TAC, and ROS-TAC scores in semen from 127 patients and 24 healthy controls. Of the patients, 56 had varicocele, eight had varicocele with prostatitis, 35 had vasectomy reversals, and 28 had Idiopathic infertility. ROS levels were higher among infertile men, especially those with varicocele with prostatitis (mean ${\pm}$ SE, 3.25 ${\pm}$ 0.89) and vasectomy reversals (2.65 ${\pm}$ 1.01). All infertility groups had significantly lower ROS-TAC scores than control. ROS-TAC score identified 80% of patients and was significantly better than ROS at identifying varicocele and idiopathic infertility. The 13 patients whose partners later achieved pregnancies had a mean ROS-TAC score of 47.7 ${\pm}$ 13.2, similar to controls but significantly higher than the 39 patients who remained infertile (35.8 ${\pm}$ 15.0; P < 0.01). ROS-TAC score is a novel measure of oxidative stress and Is superior to ROS or TAC alone in discriminating between fertile and infertile men. Infertile men with male factor or idiopathic diagnoses had significantly lower ROS-TAC scores than controls, and men with male factor diagnoses that eventually were able to initiate a successful pregnancy had significantly higher ROS-TAC scores than those who failed.

• Journal of Life Science
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• v.26 no.1
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• pp.8-16
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• 2016

Reactive oxygen species (ROS), at appropriate concentrations, mediate various normal cellular functions, including defense against pathogens, signal transduction, cellular growth, and gene expression. A recent study demonstrated that ROS and ROS-generating NADPH oxidase (Nox) are important in self-renewal and neuronal differentiation of subventricular zone (SVZ) neural stem cells in adult mouse brains. In this study, we found that endogenous ROS were detected in SVZ neural stem cells cultured from postnatal mouse brains. Nox4 was predominantly expressed in cultured cells, while the levels of the Nox1 and Nox2 transcripts were very low. In addition, the Nox4 gene was highly upregulated (by up to 10-fold) during neuronal differentiation. Immunocytochemical analysis detected the Nox4 protein mainly in neurons positive for the neuronal specific tubulin Tuj1. After differentiation, endogenous ROS were detected exclusively in neuron-like cells with processes. In addition, perturbation of the cellular redox state with N-acetyl cysteine, a ROS scavenger, during neuronal differentiation greatly inhibited neurogenesis. Lastly, knockdown of Nox4 using short hairpin RNA decreased neurogenesis. These findings suggest that Nox4 may be a major ROS-generating enzyme in postnatal SVZ neural stem cells, and Nox4-mediated ROS generation may be important in their neuronal differentiation.

• Parasites, Hosts and Diseases
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• v.51 no.1
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• pp.61-68
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• 2013

Entamoeba histolytica, which causes amoebic colitis and occasionally liver abscess in humans, is able to induce host cell death. However, signaling mechanisms of colon cell death induced by E. histolytica are not fully elucidated. In this study, we investigated the signaling role of NOX in cell death of HT29 colonic epithelial cells induced by E. histolytica. Incubation of HT29 cells with amoebic trophozoites resulted in DNA fragmentation that is a hallmark of apoptotic cell death. In addition, E. histolytica generate intracellular reactive oxygen species (ROS) in a contact-dependent manner. Inhibition of intracellular ROS level with treatment with DPI, an inhibitor of NADPH oxidases (NOXs), decreased Entamoebainduced ROS generation and cell death in HT29 cells. However, pan-caspase inhibitor did not affect E. histolytica-induced HT29 cell death. In HT29 cells, catalytic subunit NOX1 and regulatory subunit Rac1 for NOX1 activation were highly expressed. We next investigated whether NADPH oxidase 1 (NOX1)-derived ROS is closely associated with HT29 cell death induced by E. histolytica. Suppression of Rac1 by siRNA significantly inhibited Entamoeba-induced cell death. Moreover, knockdown of NOX1 by siRNA, effectively inhibited E. histolytica-triggered DNA fragmentation in HT29 cells. These results suggest that NOX1-derived ROS is required for apoptotic cell death in HT29 colon epithelial cells induced by E. histolytica.

• Korean Journal of Food Science and Technology
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• v.46 no.4
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• pp.498-504
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• 2014

Allium senescens L. is perennial plant of the Liliaceae family that grows throughout Korea. In this study, we investigated the effect of Allium senescens L. methanol extracts on reactive oxygen species (ROS) production and lipid accumulation during adipogenesis. Our results indicated that 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity of Allium senescens L. methanol extracts increased in a dose-dependent manner. Allium senescens L. methanol extracts suppressed ROS production and lipid accumulation during adipogenesis. In addition, Allium senescens L. methanol extracts inhibited the mRNA expression of the pro-oxidant enzyme, such as G6PDH and lead to a reduction in the mRNA levels of the transcription factors, such as sterol regulatory element binding proteins 1c, peroxisome proliferator-activated receptor ${\gamma}$, and CCAAT/enhancer-binding proteins ${\alpha}$. These results indicate that Allium senescens L. methanol extracts inhibit adipogenesis by modulating ROS production associated with ROS-regulating genes and directly down-regulating adipogenic transcription factors.

• Korean Journal of Clinical Laboratory Science
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• v.45 no.3
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• pp.114-119
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• 2013

Potassium is essential for the proper functioning of the ears. The inner ear's endolymph differs from all other extracellular fluids (in its positive potential) and in the ionic compositions in the various parts of the endolymphatic space. Ion concentration of the endolymph is 150 mM of potassium, which is comparable to the concentrations in other organs. Cisplatin (cis-diamminedichloroplatinum II: CDDP) is one of the most effective anticancer drugs, widely used against various tumors. However, its clinical use is limited by the onset of severe side effects, including ototoxicity and nephrotoxicity. For ototoxicity, a number of evidences in cytotoxic mechanism of cisplatin, including perturbation of redox status, increase in lipid peroxydation, and formation of DNA adduct, have been suggested. Therefore, in this study, the author investigated the relationship between the potassium ions on cisplatin-induced cytotoxicity in HEI-OC1 cells associated with reactive oxygen species (ROS). KCNE1 gene expression by the concentration of intracellular potassium appeared in the plasma membrane and increased the concentration of intracellular potassium. Cisplatin decreased the viability of HEI-OC1 cells, but the KCNE1 gene increased. Also, the KCNE1 gene significantly suppressed generation of intracellular ROS by cisplatin. Western blot analysis showed that the KCNE1 gene increased phase II detoxification enzymes markers such as superoxide dismutase 1 (SOD1), superoxide dismutase (SOD2), NAD(P)H:quinine oxidoreductases (NQO1), which were associated with the scavenger of ROS. These results suggest that the KCNE1 gene for intracellular potassium concentration ultimately prevents ROS generation from cisplatin and further contributes to protect auditory sensory hair cells from ROS produced by cisplatin.

• Archives of Pharmacal Research
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• v.27 no.8
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• pp.845-849
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• 2004

Many studies have focused on the anticarcinogenic, antimutagenic or chemopreventive activi-ties of capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) which is a major pungent ingredient in red pepper. We have previously shown that capsaicin selectively induces apoptosis in H-ras-transformed MCF10A human breast epithelial cells but not in their normal cell counter-parts (Int. J. Cancer, 103, 475-482,2003). In this study, we investigated the possible roles of reactive oxygen species (ROS) and Rac1 in capsaicin-induced apoptosis of H-ras MCF10A cells. Selective induction of ROS generation by capsaicin treatment was observed only in H-ras MCF10A cells. Pretreatment of H-ras MCF10A cells with an antioxidant N-acetylcysteine(NAC) significantly reversed capsaicin-induced growth inhibition, suggesting that ROS may mediate the apoptosis of H-ras-transformed cells induced by capsaicin. Rac1 was prominently activated by H-ras in MCF10A cells. Based on the studies using a wild type Rac1 and a domi-nant negative Rac1 constructs, we propose that Rac1 activity is critical for inhibitory effect of capsaicin on growth of H-ras-transformed MCF10A cells possibly through ROS generation.

• Journal of Korean society of Dental Hygiene
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• v.21 no.5
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• pp.545-553
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• 2021

Objectives: This study aimed to investigate the cytotoxicity of Nexus RMGIC, an indirect restorative cement, on cell survival rate and reactive oxygen species (ROS) production in periodontal stem cells (PDSCs). Methods: PDSCs were incubated with serially diluted Nexus RMGIC eluates with and without the addition of N-acetyl-cysteine (NAC). Cell survival was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The ROS generation was determined by measuring the fluorescence intensity for 2',7'-dichlorofluorescin diacetate. Results: Nexus RMGIC exposure decreased cell proliferation and cell survival rate in a dose-dependent manner (1:8, 1:4, 1:2, 1:1) in PDSCs. The cytotoxicity of Nexus RMGIC was inhibited by treatment with 10-mM NAC. In addition, the production of ROS was detected by immunofluorescence after PDSCs were exposed to Nexus RMGIC. However, ROS generation was significantly suppressed in the NAC pretreatment compared with the Nexus RMGIC group. Conclusions: Nexus RMGIC increased the cytotoxicity and ROS generation. ROS was involved in Nexus RMGIC-induced cell toxicity.

• Biomolecules & Therapeutics
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• v.28 no.1
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• pp.104-109
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• 2020

Probenecid is a representative drug used in the treatment of gout. A recent study showed that probenecid effectively inhibits oxidative stress in neural cells. In the present study, we investigated whether probenecid can affect osteoclast formation through the inhibition of reactive oxygen species (ROS) formation in RAW264.7 cells. Lipopolysaccharide (LPS)-induced ROS levels were dose-dependently reduced by probenecid. Fluorescence microscopy analysis clearly showed that probenecid inhibits the generation of ROS. Western blot analysis indicated that probenecid affects two downstream signaling molecules of ROS, cyclooxygenase 2 (COX-2) and c-Jun N-terminal kinase (JNK). These results indicate that probenecid inhibits ROS generation and exerts antiosteoclastogenic activity by inhibiting the COX-2 and JNK pathways. These results suggest that probenecid could potentially be used as a therapeutic agent to prevent bone resorption.

• Archives of Pharmacal Research
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• v.26 no.10
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• pp.809-815
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• 2003

Since reactive oxygen species (ROS) and hydroxyl radicals ($^-OH$) play an important role in the pathogenesis of many human degenerative diseases, much attention has focused on the development of safe and effective antioxidants. Preliminary experiments have revealed that the methanol (MeOH) extract of the stem of Prunus davidiana exerts inhibitory/scavenging activities on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals, total ROS and peroxynitrites ($ONOO^-$). In the present study, the antioxidant activities of this MeOH extract and the organic solvent-soluble fractions, dichloromethane (CH$_2$Cl$_2$), ethyl acetate (EtOAc), and n-butanol (n-BuOH), and the water layer of P. davidiana stem were evaluated for the potential to inhibit $^-OH$ and total ROS generation in kidney homogenates using 2',7'-dichlorodihydrofluorescein diacetate (DCHF-DA), and for the potential to scavenge authentic $ONOO^-$. We also evaluated the inhibitory activity of seven flavonoids isolated from P. davidiana stem, kaempferol, kaempferol 7-Ο-$\beta$-D-glucoside, (+)-catechin, dihydrokaempferol, hesperetin 5-Ο-$\beta$-D-glucoside, naringenin and its 7-Ο-$\beta$-D-glucoside, on the total ROS, $^-OH$ and $ONOO^-$ systems. For the further elucidation of the structure-inhibitory activity relationship of flavonoids on total ROS and 'OH generation, we measured the antioxidant activity of sixteen flavonoids available, including three active flavonoids isolated from P. davidiana, on the total ROS and 'OH systems. We found that the inhibitory activity on total ROS generation increases in strength with more numerous hydroxyl groups on their structures. Also, the presence of an ortho-hydroxyl group, whether on the Aring or S-ring, and a 3-hydroxyl group on the C-ring increased the inhibitory activity on both total ROS and $^-OH$ generation.