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Featured researches published by Yoshihisa Akiyama.
Bioorganic & Medicinal Chemistry Letters | 1997
Yoshihisa Akiyama; Seiji Tsutsumi; Emiko Hatsushiba; Shoukichi Ohuchi; Tsuneo Okonogi
Abstract We report the synthesis and evaluation of α-keto thiazole derivatives such as D-Phe-Pro-Arg-thiazole 9 as a novel type of thrombin inhibitor. Tripeptidyl α-keto thiazole 9 exhibited the inhibitory activity of thrombin at nanomolar levels and showed a more potent prolongation effect on clotting time than argatroban at a dose of 3 mg/kg intravenously.
Heterocycles | 2007
Nobuto Minowa; Yukiko Hiraiwa; Yoshihisa Akiyama; Kazunori Maebashi; Takayuki Usui; Daishiro Ikeda
Novel homologated aminoglycosides having a seven-membered ring were designed and synthesized by treatment of 5-keto arbekacin with diazomethane in CH 2 Cl 2 -Et 2 O. The ring-expanded arbekacin analogue showed good antibacterial activity against Staphylococcus aureus and Escherichia coli including aminoglycoside-resistant bacterial strain.
The Journal of Antibiotics | 2018
Yoko Hirai; Kazunori Maebashi; Hideki Fushimi; Yukiko Hiraiwa; Shoichi Murakami; Takayuki Usui; Yoshihisa Akiyama; Nobuto Minowa; Daishiro Ikeda
To overcome serious methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa infections, we synthesized TS2037, 5,4″-diepi-arbekacin, a novel aminoglycoside antibiotic, and evaluated its biological properties. TS2037 showed broad-range, as well as robust antibacterial activities against Gram-positive and Gram-negative bacteria. The MIC50 and MIC90 of TS2037 against clinical isolates of MRSA (n = 54) were both 0.25 µg/mL, and no resistant strain was observed. The MIC50 and MIC90 of TS2037 against clinical isolates of P. aeruginosa (n = 54) were 1 and 4 µg/mL, respectively. TS2037 and arbekacin, anti-MRSA aminoglycoside, were more stable against AAC(6′)-APH(2″), aminoglycoside-6′-N-acetyltransferase and 2″-O-phosphotransferase, produced by resistant S. aureus than gentamicin. Therapeutic efficacies of TS2037 in the mouse models of systemic infection with MRSA were superior to those of arbekacin, vancomycin, and linezolid. The efficacy of TS2037 against systemic infection caused by P. aeruginosa producing AAC(6′)-II was superior to those of arbekacin and amikacin. In the nephrotoxicity risk screening, the release of free N-acetyl-β-d-glucosaminidase from the kidney epithelial cell line after treatment with TS2037 at 2.5 and 5.0 μM were 2.0 and 2.1 (U/L), respectively, which were about two times higher than those of arbekacin. In conclusion, TS2037 exhibited the most potent antibacterial activity among aminoglycosides tested against both MRSA and P. aeruginosa in vitro and in vivo, although its nephrotoxicity risk remains to be improved.
Bioorganic & Medicinal Chemistry Letters | 2007
Yukiko Hiraiwa; Takayuki Usui; Yoshihisa Akiyama; Kazunori Maebashi; Nobuto Minowa; Daishiro Ikeda
Bioorganic & Medicinal Chemistry Letters | 2007
Yukiko Hiraiwa; Nobuto Minowa; Takayuki Usui; Yoshihisa Akiyama; Kazunori Maebashi; Daishiro Ikeda
Bioorganic & Medicinal Chemistry Letters | 2006
Nobuto Minowa; Yoshihisa Akiyama; Yukiko Hiraiwa; Kazunori Maebashi; Takayuki Usui; Daishiro Ikeda
Archive | 2005
Nobuto Minowa; Takayuki Usui; Yoshihisa Akiyama; Yukiko Hiraiwa; Toshio Yoneta; Toshifumi Hasegawa; Kazunori Maebashi; Takashi Ida; Kazuko Katsumata; Keiko Otsuka; Daishiro Ikeda
Archive | 2005
Nobuto Minowa; Takayuki Usui; Yoshihisa Akiyama; Hirawa Yukiko; Toshio Yoneta; Toshifumi Hasegawa; Kazunori Maebashi; Takashi Ida; Kazuko Katsumata; Keiko Otsuka; Daishiro Ikeda
Archive | 1994
Yoshihisa Akiyama; Emiko Hatsushiba; Tsuneo Okonogi; Shokichi Ouchi; Seiji Tsutsumi; 恵実子 初芝; 誠司 堤; 章吉 大内; 恒夫 小此木; 佳央 秋山
Archive | 2007
Yoshihiko Kobayashi; Yoshihisa Akiyama; Takeshi Murakami; Nobuto Minowa; Masaki Tsushima; Yukiko Hiraiwa; Shoichi Murakami; Mitsuhiro Abe; Kazushige Sasaki; Shigeru Hoshiko; Toshiaki Miyake; Yoshiaki Takahashi; Daishiro Ikeda