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Tomohiro M. Oyama
University of Tokushima
CytotoxicityChemistryOxidative stressBiochemistryIntracellular
26Publications
11H-index
386Citations
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Publications 26
Newest
#2Keisuke OyamaH-Index: 5
Last. Yasuooyama (University of Tokushima)H-Index: 30
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Abstract N-(3-oxododecanoyl)- l -homoserine-lactone (ODHL), a quorum sensing molecule, affects intracellular Zn2+ concentration ([Zn2+]i) and cellular levels of nonprotein thiols ([NPT]i) of rat thymic lymphocytes, both of which are assumed to affect cell vulnerability to oxidative stress. Therefore, it is interesting to examine the effects of ODHL on the cells under oxidative stress. ODHL augmented the cytotoxicity of H2O2, but not calcium ionophore A23187. ODHL potentiated the H2O2-induced ele...
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#1Yumiko Kanemoto-Kataoka (Kitasato University)H-Index: 2
#2Keisuke Oyama (Kitasato University)H-Index: 5
Last. Yasuooyama (Kitasato University)H-Index: 30
view all 5 authors...
Ziram, a dithiocarbamate fungicide, protects various vegetables and fruits against infections by fungus. Recently, there have been increasing anxieties about the risks in the use of dithiocarbamate fungicides. Our previous studies showed that Zn2+ was a determinant of Ziram cytotoxicity. In addition, Zn2+ is linked to H2O2 cytotoxicity. Therefore, in this study, we aimed to test the hypothesis that Ziram could augment the cytotoxicity of H2O2 by examining the changes induced by Ziram in some cel...
2 CitationsSource
#1Yumiko Kanemoto-Kataoka (University of Tokushima)H-Index: 2
#2Tomohiro M. Oyama (University of Tokushima)H-Index: 11
Last. Yasuooyama (University of Tokushima)H-Index: 30
view all 4 authors...
Ziram, one of the dithiocarbamate fungicides, is widely applied to agriculture because this agent protects various crops from fungal infections. Risks of dithiocarbamate biocide use are of concern. It was previously reported that Ziram increased the intracellular concentration of Zn2+. Therefore, we cytometrically studied the mechanism of Zn2+-dependent lethal actions of Ziram on rat lymphocytes at environmentally relevant Zn2+ levels. Membrane and cellular parameters of rat lymphocytes were est...
3 CitationsSource
#1Tomohiro M. OyamaH-Index: 11
#2Eri FukunagaH-Index: 4
Last. YasuooyamaH-Index: 30
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We examined the effect of clioquinol on the process of cell death induced by hydrogen peroxide (H2O2) using a flow cytometric technique with propidium iodide and annexin V-FITC in order to see if clioquinol augments the toxicity caused by oxidative stress. Clioquinol (100 nM) alone did not change the process of spontaneous cell death. However, the agent accelerated the process of cell death induced by 300 μM H2O2. Result indicates that clioquinol augments the cytotoxicity induced by H2O2. Theref...
#1Yumiko Kanemoto-Kataoka (University of Tokushima)H-Index: 2
#2Tomohiro M. Oyama (University of Tokushima)H-Index: 11
Last. Yasuooyama (University of Tokushima)H-Index: 30
view all 4 authors...
Abstract Dithiocarbamate fungicides are used as alternative antifouling agents to highly toxic organotin antifouling agents, such as tri-n-butyltin and triphenyltin. There are some concerns regarding their environmental and health risks. It has been shown that tri-n-butyltin increases intracellular Zn2+ levels of mammalian lymphocytes. Therefore, we examined the effects of dithiocarbamate fungicides (Ziram, Thiram, and Zineb) on rat thymic lymphocytes using a flow-cytometric technique to elucida...
10 CitationsSource
#1Eri Fukunaga (University of Tokushima)H-Index: 4
#2Tomohiro M. Oyama (University of Tokushima)H-Index: 11
Last. Yasuooyama (University of Tokushima)H-Index: 30
view all 3 authors...
High amounts of 2-n-octyl-4-isothiazolin-3-one (OIT), an antimicrobial, are found in wet polyvinyl alcohol towels with cooling properties. Although the diverse actions of OIT are of concern, information on its cellular actions is limited. In this study, we examined the effects of OIT on Zn2+ levels in rat thymocytes by flow cytometric analysis with FluoZin-3, and assessed the cytotoxicity of this agent. OIT (1–3 μM) significantly increased the intensity of the FluoZin-3 fluorescence. Removal of ...
4 CitationsSource
#1Tomohiro M. Oyama (University of Tokushima)H-Index: 11
#2Keisuke Oyama (University of Tokushima)H-Index: 5
Last. Yasuooyama (University of Tokushima)H-Index: 30
view all 5 authors...
Clioquinol, a lipophilic Zn2+ chelator, has emerged as a potential novel therapeutic agent for several diseases such as cancer and Alzheimer's disease. Clioquinol has different effects on the intracellular Zn2+ concentrations in rat thymocytes, depending on its concentration and extracellular Zn2+ levels. In this study, we examined the effect of clioquinol on cells under oxidative stress induced by hydrogen peroxide (H2O2) by using a conventional flow cytometric technique with appropriate fluore...
2 CitationsSource
#1Tomohiro M. Oyama (University of Tokushima)H-Index: 11
#2Shiro Ishida (University of Tokushima)H-Index: 16
Last. Yasuooyama (University of Tokushima)H-Index: 30
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Abstract Aims Clioquinol is emerging as a potential therapy for some diseases, such as Alzheimer disease and cancer. This agent is a lipophilic chelator of Zn 2 + . In this study, the effect of clioquinol on the intracellular Zn 2 + level was examined in order to gain insights into the toxicological profile of clioquinol. Main methods The effect of clioquinol was estimated using a flow cytometer and FluoZin-3, a fluorescent indicator for Zn 2 + , in rat thymocytes. Key findings Clioquinol, at co...
4 CitationsSource
#1Tomohiro M. Oyama (Tokushima Bunri University)H-Index: 11
#2Minoru Saito (Tokushima Bunri University)H-Index: 3
Last. Yasuooyama (Tokushima Bunri University)H-Index: 30
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Abstract Zinc pyrithione is used as an antifouling agent. However, the environmental impacts of zinc pyrithione have recently been of concern. Zinc induces diverse actions during oxidative stress; therefore, we examined the effect of zinc pyrithione on rat thymocytes suffering from oxidative stress using appropriate fluorescent probes. The cytotoxicity of zinc pyrithione was not observed when the cells were incubated with 3 μM zinc pyrithione for 3 h. However, zinc pyrithione at nanomolar concen...
17 CitationsSource
#1Akio Kinazaki (Tokushima Bunri University)H-Index: 2
#2Hongqin Chen (University of Tokushima)H-Index: 1
Last. Yasuooyama (University of Tokushima)H-Index: 30
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Although the ability of zinc to retard the oxidative process has been recognized for many years, zinc itself has been reported to induce oxidative stress. In order to give some insights into elucidating the role of intracellular Zn2+ in cells suffering from oxidative stress, the effects of N-ethylmaleimide (NEM) and ZnCl2 on cellular thiol content and intracellular Zn2+ concentration were studied by use of 5-chloromethylfluorescein diacetate (5-CMF-DA) and FluoZin-3 pentaacetoxymethyl ester (Flu...
33 CitationsSource
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