Publications by authors named "Mamiko Asano"

We previously reported that MDA-MB-231 and MCF-7 cells, which are breast cancer cell lines and have cancer and cancer-initiating cells (CICs), were killed following normothermic microwave irradiation in which the cellular temperature was maintained at 37°C. In this study, we investigated the percentages of live or dead cells among CD44/CD24 cells, which were defined as CICs among MDA-MB-231 and MCF-7 cells, and other types of cells in response to microwave irradiation. CD44/CD24 cells among MDA-MB-231 cells were killed, thereby decreasing the number of cells, whereas the number of live CD44/CD24 MCF-7 cells was increased following microwave irradiation.

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Microwaves have been used in various cancer therapies to generate heat and increase tumor cell temperature; however, their use is limited by their side-effects in normal cells and the acquisition of heat resistance. We previously developed a microwave irradiation method that kills cultured cancer cells, including a human promyelomonocytic leukemia (HL-60) cell line, by maintaining a cellular temperature of 37 °C during treatment. In the present study, we investigated the mechanisms underlying HL-60 cell death during this treatment.

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We investigated the effects of microwave irradiation under normothermic conditions on cultured cells. For this study, we developed an irradiation system constituted with semiconductor microwave oscillator (2.45 GHz) and thermos-regulatory applicator, which could irradiate microwaves at varied output powers to maintain the temperature of cultured cells at 37 °C.

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Dimeric indole alkaloids (DIAs), such as vinblastine and vincristine, found in Catharanthus roseus are used clinically as antitumor drugs. A stable supply of DIAs is desired because these alkaloids are very expensive due to their low abundance in plants. A coupling reaction between catharanthine (CAT) and vindoline (VID) is the rate-limiting step of DIAs biosynthesis in planta.

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Rhodamine B hydrazide can be used to detect hydroxyl radicals in plant cells. RBH was easily inserted into plant cells without any pretreatment, and specifically reacted with intracellular hydroxyl radicals produced by antimycin A. RBH will be a powerful tool for detecting hydroxyl radicals in plant cells.

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Spectrophotometric determination of hydrogen peroxide was accomplished with osmium(VIII) and m-carboxyphenylfluorone (MCPF) in the presence of cetyltrimethylammonium chloride (CTAC). In the determination of hydrogen peroxide based on the fading of the color of osmium(VIII)-MCPF complex, Beer's law was obeyed in the range 20-406 ng mL(-1), with an effective molar absorption coefficient (at 580 nm) of 5.21×10(4) L mol(-1) cm(-1) and a relative standard deviation of 0.

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A simple fluorophotometric method for the determination of histone has been developed. This method involves a fluorescence quenching reaction that results in the formation of a complex of manganese(II), 3,4,5,6-tetrafluoro-2-carboxyphenylfluorone (TFCPF), and histone in a non-ionic surfactant micellar medium. The calibration curve was found to be linear in the range of 0.

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Spectrophotometric determination of titanium(IV) was accomplished with o-carboxyphenylfluorone (OCPF) in the presence of hexadecyltrimethyl ammonium chloride (HTAC) under strongly acidic media. In the determination of titanium(IV), Beer's law was obeyed in the range of 24-340 ng mL(-1) with an effective molar absorption coefficient (at 530 nm) and relative standard deviation of 2.24 × 10(5)dm(3)mol(-1)cm(-1) and 0.

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An improved method for the fluorophotometric determination of trace Al(III) has been developed. This method involves a fluorescence quenching reaction that results in the formation of an m-carboxyphenylfluorone-Al(III) complex in a poly(N-vinylpyrrolidone) micellar medium. The calibration curve was found to be linear in the range of 0.

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Spectrophotometric determination of cobalt(II) was accomplished with vanillilfluorone (VF) in the presence of dimethylbenzyltetradecylammonium chloride (Zephiramine, Zep). In the determination of cobalt(II), Beer's law was obeyed in the range of 24-470 ng/ml, with an effective molar absorption coefficient (at 575 nm) and relative standard deviation of 1.35×10(5) l mol(-1) cm(-1) and 0.

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We have found that coupling between catharanthine and vindoline occurs non-enzymatically in the presence of flavin mononucleotide and manganese ions with near-ultraviolet light irradiation in vitro. The present study found that the concentrations of catharanthine and vindoline in Catharanthus roseus decreased and those of dimeric indole alkaloids increased under near-ultraviolet light at 4 degrees C. It indicates that this coupling reaction at 4 degrees C occurs non-enzymatically.

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