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Your search keyword '"Nishida, Atsuyuki"' showing total 15 results
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15 results on '"Nishida, Atsuyuki"'

8. Assessment of 8-Methosypsoralen, Lomefloxacin, Sparfloxacin, and Pirfenidone phototoxicity in Long-Evans Rats.

Author

Adachi, Tamiko, Satou, Yuko, Satou, Hiroko, Shibata, Hiroshi, Miwa, Satoko, Iwase, Yumiko, Yamamoto, Toshinobu, Nishida, Atsuyuki, and Masutomi, Naoya

Subjects
PHARMACOLOGY, PHOTOSENSITIVITY, DRUG development, DRUG toxicity, LABORATORY rats
Abstract

Phototoxicity has a strong impact on drug development. Although several animal models have been developed to quantitatively assess human risks, none have been validated for standardized use. In this study, we validated an in vivo phototoxicity model using Long-Evans (LE) rats treated with 4 well-known phototoxic drugs, namely 8-methoxypsoralen, lomefloxacin, sparfloxacin, and pirfenidone. Daily macroscopic observations of skin and eyes, ophthalmological examinations 4 days after dosing, and blood sampling for toxicokinetics (TKs) were performed after exposure of treated animals to ultraviolet, and dose-dependent eye and/or skin reactions were noted for all compounds. Margins of safety were calculated when possible and correlated well with known relative phototoxicity of the 4 compounds. We conclude that the present in vivo phototoxicity assay using LE rats with TK analysis can be used to quantitatively predict the risk of pharmaceutical phototoxicity in humans. [ABSTRACT FROM AUTHOR]

Published
2015
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14. Anti-Aging Effects of Nanpao®, a Kampo Medicine, on Reproductive Functions in Female Rats.

Author

Ichihashi, Masaru, Matsuda, Aoi, Honda, Tatsuya, Kokubun, Chisato, Hashimoto, Yoshikatsu, Yano, Kouji, Nishida, Atsuyuki, and Kitamura, Kazuyuki

Subjects
DRUG use testing, LABORATORY rats, CESAREAN section, SEXUAL cycle, ESTRUS
Abstract

The improvement effect of Nanpao, a Kampo medicine, on the age-related decline in reproductive function was evaluated in female rats given the test drug for a long-term period. Young rats were allocated to the cesarean section and natural delivery groups to examine reproductive performance (young rat groups). Five-month-old rats were allocated to the 3 groups (aged rat groups): 1 — control and 2 — Nanpao-treated groups. They were given orally in a dose of 0, 30 or 100mg/kg/day of the test drug, respectively. In aged rats, the first mating experiment was initiated at week 21 of dosing to evaluate reproductive performance by natural delivery and the second mating experiment at week 31 of dosing was evaluated by cesarean section. In the first and second mating experiments, various reproductive functions decreased in aged rats as compared to the young rats. On the other hand, loss of regular estrous cycles, decreases in delivery and pregnancy rates and mean fetal weights were inhibited in the treated groups as compared to the control group. In addition, decreases in the numbers of mean live offspring and fetuses were inhibited in the 100mg/kg/day group. In conclusion, Nanpao maintained normal embryo-foetal development in female rats. [ABSTRACT FROM AUTHOR]

Published
2008
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15. Targeted Disruption of Na+/Ca2+Exchanger Gene Leads to Cardiomyocyte Apoptosis and Defects in Heartbeat*

Author

Wakimoto, Koji, Kobayashi, Kinji, Kuro-o, Makoto, Yao, Atsushi, Iwamoto, Takahiro, Yanaka, Noriyuki, Kita, Satomi, Nishida, Atsuyuki, Azuma, Sadahiro, Toyoda, Yutaka, Omori, Kenji, Imahie, Hiroshi, Oka, Toru, Kudoh, Sumiyo, Kohmoto, Osami, Yazaki, Yoshio, Shigekawa, Munekazu, Imai, Yuji, Nabeshima, Yo-ichi, and Komuro, Issei

Abstract

Ca2+, which enters cardiac myocytes through voltage-dependent Ca2+channels during excitation, is extruded from myocytes primarily by the Na+/Ca2+exchanger (NCX1) during relaxation. The increase in intracellular Ca2+concentration in myocytes by digitalis treatment and after ischemia/reperfusion is also thought to result from the reverse mode of the Na+/Ca2+exchange mechanism. However, the precise roles of the NCX1 are still unclear because of the lack of its specific inhibitors. We generated Ncx1-deficient mice by gene targeting to determine the in vivofunction of the exchanger. Homozygous Ncx1-deficient mice died between embryonic days 9 and 10. Their hearts did not beat, and cardiac myocytes showed apoptosis. No forward mode or reverse mode of the Na+/Ca2+exchange activity was detected in null mutant hearts. The Na+-dependent Ca2+exchange activity as well as protein content of NCX1 were decreased by ∼50% in the heart, kidney, aorta, and smooth muscle cells of the heterozygous mice, and tension development of the aortic ring in Na+-free solution was markedly impaired in heterozygous mice. These findings suggest that NCX1 is required for heartbeats and survival of cardiac myocytes in embryos and plays critical roles in Na+-dependent Ca2+handling in the heart and aorta.

Published
2000
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