Determination of ultimate substances on arsenic carcinogenesis and in vivo formation mechanisms of their substances

• Project/Area Number: 17590110
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Environmental pharmacy
• Research Institution: Nihon University
• Principal Investigator: YAMANAKA Kenzo Nihon University, College of Pharmacy, Professor (50182572)
• Co-Investigator(Kenkyū-buntansha): KATO Koichi Nihon University, College of Pharmacy, Assistant Professor (60246931)
• Project Period (FY): 2005 – 2006
• Project Status: Completed (Fiscal Year 2006)
• Budget Amount: ¥2,700,000 (Direct Cost: ¥2,700,000); Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000); Fiscal Year 2005: ¥1,700,000 (Direct Cost: ¥1,700,000)
• Keywords: Environmental carcinogenesis / Arsenic carcinogenesis / Dimethylarsinic acid / Dimethylarsine / Dimethylarsine radical / Dimethylarsine peroxy radical / 発癌プロモーション / 発癌イニシエーション / 酸化ストレス / マウス短期肺発癌実験 / ジメチルアシン / ジメチルヒ素化合粒 / メチル化代謝

Research Abstract

Continuous and laser photolysis studies of (CH_3)_2As^<(III)>I were carried out in methanol solutions. The photoproduct obtained with the continuous photolysis of the aerated solutions was identified as {(CH_3)_2As^(V)(OH)_2}+{(CH_3)_2As^(V)O(OH)}_2][I_3] by X-ray crystallography. The laser flash photolysis of (CH_3)_2As^(III)I in a degassed methanol gives a transient spectrum of dimethylarsine radical, (CH_3)_2As^(III), with a broad peak centered around 560 nm. The arsinous radical, (CH_3)_2As^(III), decays according to second order kinetics to regenerate (CH_3)_2As(III)^I. In the presence of oxygen, (CH_3)_2As^(III) reacts with oxygen to yield the peroxy radicals, [(CH_3)_2As^(III)(O_2)] with the bimolecular rate constant, 2.0 x 10_9 M_-1 s_-1. The peroxy radical having weak and broad absorption in the wavelength region λ> 500 nm decays according to first order kinetics with a rate constant 5.0 x 10_5 s_-1. It is suggested that the peroxy radical unimolecularly converts to (CH_3)_2As^(V)(O)O, which eventually turns to the product {(CH_3)_2As^(V)(OH)_2}+{(CH_3)_2As^(V)O(OH)}_2][I_3].

Research Products

• [Journal Article] Photochemical reaction of dimethylarsious iodide in aerated methanol:A contribution to arsenic radical chemistry (2008)
  • Author(s): Kenzo Yamanaka, Hiroshi Okimi, Hiroyuki Suzuki, Yusuke Tajima, Hirotaka Sonoki, Masahisa Osawa, Takashi Saito, Hirotomo Hase, Yoko Miyatake, Shoji Okada, Yoshio Miyazaki, Mikio Hoshino
  • Journal Title: Journal of Photochemistry and Photobiology A:Chemistry
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Photochemical reaction of dimethylarsinous iodide in aerated methanol : A contribution to arsenic radical chemistry (2008)
  • Author(s): Kenzo Yamanaka, Hiroshi Okimi, Hiroyuki Suzuki, Yusuke Tajima, Hirotaka Sonoki, Masahisa Osawa, Takashi Saito, Hirotomo Hase, Yoko Miyatake, Shoji Okada, Yoshio Miyazaki, Mikio Hoshino
  • Journal Title: Journal of Photochemistry and Photobiology A : Chemistry (in press)
  • Description: 「研究成果報告書概要(欧文)」より