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82 results on '"Murai, Takashi"'

51. Strain Differences in Sensitivity to the Promoting Effect of Sodium L-Ascorbate in a Two-stage Rat Urinary Bladder Carcinogenesis Model

Author

Murai, Takashi, primary, Mori, Satoru, additional, Hosono, Motoko, additional, Takashima, Akira, additional, Machine, Setsuko, additional, Oohara, Tadao, additional, Yamashita, Hirofumi, additional, Makino, Susumu, additional, Matsuda, Tsutomu, additional, Wanibuchi, Hideki, additional, and Fukushima, Shoji, additional

Published
1997
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63. Effect of KP-840 on cerebral, vertebral and renal blood flow.

Author

Miyao, Yoshinobu, primary, Kurasaki, Shigeru, additional, Ohyama, Tadashi, additional, Hori, Toshimitsu, additional, Muraoka, Kanji, additional, Nakajima, Tsutomu, additional, Okamoto, Taira, additional, Murai, Takashi, additional, Nakagawa, Terutake, additional, Yajima, Motoyuki, additional, and Nakanishi, Michio, additional

Published
1991
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66. Induction of tumors in the colon and liver of the immunodeficient (SCID) mouse by 2-amino-3-methylimidazo[4,5-f ]quinoline (IQ)—modulation by long-chain fatty acids.

Author

Salim, Elsayed I., Wanibuchi, Hideki, Morimura, Keiichirou, Murai, Takashi, Makino, Susumu, Nomura, Taisei, and Fukushima, Shoji

Abstract

We have recently shown that immunodeficient (SCID) mice, which lack functional T and B cells, are highly susceptible to low dose site specific induction of colon aberrant crypt foci (ACF), surrogates for colon tumors, by 2-amino-3-methylimidazo[4,5-f ]quinoline (IQ). To test whether long-term exposure to a high dose in the diet might prove carcinogenic to the SCID mouse colon, in contrast to other mice strains tested to date, the compound was administered at 300 p.p.m. in the diet to female 6–7-week-old SCID mice for 32 weeks. IQ induced high numbers of ACF, hyperplastic polyps, dysplasia, and colon adenomas, as well as hepatocellular altered foci and liver adenomas. Induction of colon tumors did not correlate with the main sites where ACF developed, the proximal colon, however, being seen mainly in the mid and distal colon. Induction of colon tumors correlated significantly with the incidence of dysplasia, crypt height, the mitotic index, cell proliferation and numbers of 8-hydroxydeoxyguanosine (8-OHdG)-positive cells in the colon crypt, particularly in mid and distal colon. Administration of 20% ωω-6 polyunsaturated fatty acids (corn oil), ωω-3 polyunsaturated fatty acids (perilla oil), or monounsaturated fatty acids (olive oil) simultaneously with IQ in the diet resulted in: (i) inhibition of colon and liver tumor induction by corn and perilla oil, whereas olive oil showed no effects; (ii) no reduction in total numbers of ACF by corn oil or perilla oil but significant suppression in the olive oil treated group; (iii) inhibition of tumor development particularly by ωω-3 polyunsaturated fatty acids in perilla oil, correlating significantly with decreased cell proliferation in both colon and liver and a marked decrease in crypt heights and mitotic indices. Selective reduction in the numbers of 8-OHdG-positive nuclei, mainly in the middle and distal colon crypts, was also found to correlate with tumor inhibition. Thus, the results indicate carcinogenicity of IQ in the colon of the SCID mouse and preventive effects of polyunsaturated fatty acids. [ABSTRACT FROM PUBLISHER]

Published
2002
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73. Design and Performance of Superconducting Magnets for Hybrid Magnets(Part I. Establishment and Tests of Hybrid Magnet System at HFLSM)

Author

Noto, Koshichi, Watanabe, Kazuo, Hoshi, Akira, Muto, Yoshio, Nagamura, Junichi, Osaki, Osamu, Sumiyoshi, Yukihiro, Hamajima, Takataro, Satow, Takashi, and Murai, Takashi

Abstract

Design, construction and performance of three superconducting magnets for the hybrid magnets installed in the High Field Laboratory for Superconducting Materials are described in detail. The compact solenoid, SM-3, without fully cryostable design forms the outer part of the most compact hybrid magnet in the world, HM-3 (32 mm bore, 20 T). Fully cryostable superconducting magnet designed under the Steckly criterion, SM-2, is the outer part of HM-2 (52 mm bore, 23 T), which has been most attractive to many experimentalists. SM-1, the outer part of HM-1 (32/52 mm bore, 31/28 T), with the Williams cryostability criterion is the world largest one of the superconducting magnets which employ Ti-doped Nb_3Sn multifilamentary conductors and can generate more than 12 T.

Published
1987

75. Possible rare involvement of <TOGGLE>O</TOGGLE><SUP>6</SUP>-methylguanine formation as a significant mutational factor in mouse urinary bladder carcinogenesis models

Author

Chen, Tianxin, Yamamoto, Shinji, Kitano, Mitsuaki, Murai, Takashi, Wanibuchi, Hideki, Matsukuma, Shoichi, Nakatsuru, Yoko, Ishikawa, Takatoshi, and Fukushima, Shoji

Abstract

O6-methylguanine is known as one of the major premutagenic lesions in the human and rodent carcinogenesis process. O6-methylguanine-DNA methyltransferase (MGMT), which repairs methylated guanine bases, might prevent the G:C to A:T transition, and transgenic mice carrying this MGMT gene have been reported to be less sensitive to the carcinogenicity of certain alkylating agents. Here we utilized MGMT transgenic mice to assess the significance of O6-methylguanine formation during urinary bladder carcinogenesis. In experiment 1, 100 and 60 ppm N-butyl-N-(4-hydroxybutyl)nitrosamine was given for 20 weeks to transgenic and non-transgenic mice in their drinking water. The incidences of urinary bladder carcinomas were not different between transgenic mice and non-transgenic mice. The mutational spectrum of the p53 gene was evaluated by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis and direct sequencing. The pattern of p53 mutations of transgenic and non-transgenic mice did not differ, and the frequencies of mutations were 40% and 42%, respectively. G:C to A:T transition mutations were particularly infrequent (1 of 14 mutations, 7%). In experiment 2, N-methyl-N-nitrosourea, which might induce O6-methylguanine in affected alleles, was given once a week, 3 times (total 5 mg) by direct instillation into the urinary bladder through an abdominal incision. No significant neoplastic lesions were detected, although the experiment was limited by severe toxicity of the treatment. p53 immunostaining was done and there was no difference in transgenic and non-transgenic mice. These results suggest that O6-methylguanine formation might not be a significant mutational factor in these mouse urinary bladder carcinogenesis models. Teratogenesis Carcinog. Mutagen. 18:101–110, 1998. © 1998 Wiley-Liss, Inc.

Published
1998
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77. Design and construction of the QC2 superconducting magnets in the SuperKEKB IR

Author

Ohuchi, Norihito, Arimoto, Yasushi, Higashi, Norio, Iwasaki, Masako, Kawai, Masanori, Kondo, Yoshinari, Kono, Hiroshi, Murai, Takashi, Takagi, Shigeyuki, Tsuchiya, Kiyosumi, Wang, Xudong, Yamaoka, Hiroshi, and Zong, Zhanguo

Subjects
07 Accelerator Technology, Physics::Accelerator Physics, Accelerator Physics
Abstract

SuperKEKB is now being constructed with a target luminosity of 8×10³⁵ which is 40 times higher than the KEKB luminosity. The luminosity can be achieved by the "Nano-Beam" accelerator scheme, in which both beams should be squeezed to about 50 nm at the beam interaction point, IP. The beam final focusing system consists of 8 superconducting quadrupole magnets, 4 superconducting solenoids and 43 superconducting corrector coils. The QC2 magnets are designed to be located in the second closest position from IP as the final beam focusing system of SuperKEKB. The two types of quadrupole magnets have been designed for the electron and positron beam lines. The QC2P for the positron beam is designed to generate the field gradient, G, of 28.1 T/m and the effective magnetic length, L, of 0.4099 m at the current, I, of 877.4 A. The QC2E for the electron beam line is designed to generate G=28.44 T/m and L=0.537 mm, 0.419 mm (for QC2LE, QC2RE) at I=977 A. In the paper, we will present the designs and the constructions of the two types of the quadrupole magnets., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

80. Photosensitivity Due to a Fluorouracil Derivative

Author

Horio, Takeshi, Murai, Takashi, and Ikai, Kouichi

Abstract

• A photosensitive lichen planus-like eruption developed in a 63-year-old man during postoperative chemotherapy with 1-(2-tetrahydrofuryl)-5-fluorouracil. The action spectrum for the photosensitivity was in the long-wave ultraviolet light (UV-A). The reaction was reproducible on readministration of the drug and exposure to UV-A. At the time of this test, a flare-up phenomenon was observed at previously involved sites. The photopatch test was negative with the drug. Patients taking the drug who had no dermatitis were not sensitive to UV-A. These observations suggest that the photosensitivity that occurred in the patient was possibly photoallergic.(Arch Dermatol 114:1498-1500, 1978)

Published
1978
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