H Okeya

Publications (2)4.35 Total impact

• Article: Methyl methacrylate activates the Gsta1 promoter.

  N Hattori, T Suzuki, S Jinno, H Okeya, A Ishikawa, C Kondo, T Hayashi, M Ito, T Kanamori, T Kawai, T Noguchi
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  ABSTRACT: Residual monomers in resin-based biomaterials cause cytotoxicity. We previously showed that methyl methacrylate (MMA) induced mRNA expression of the glutathione S-transferase alpha 1 gene (Gsta1) located downstream of the cis-acting anti-oxidant responsive element (ARE). Herein, we tested the hypothesis that MMA activated the Gsta1 promoter through the ARE. HepG2 cells were transfected with a luciferase reporter vector containing the ARE and the Gsta1 promoter (-990 to +46 bp) and cultured for 12 hrs with MMA (initial concentration, 10 mM). Analysis of the expressed luciferase activity indicated that MMA activated the promoter 2.6-fold. MMA (from 1 to 30 mM) dose-dependently increased the promoter activity, which reached a plateau between 6 and 12 hrs. In HepG2 cells transfected with a reporter vector containing 2 AREs and a TATA-like promoter, 10 mM MMA increased the reporter expression 2.8-fold. These results suggest that MMA increases Gsta1 transcription through ARE-mediated promoter activation.
  Journal of dental research 01/2009; 87(12):1117-21. · 3.46 Impact Factor
• Article: The biological properties of a novel ethyl methacrylate resin.

  T Suzuki, S Jinno, N Hattori, H Okeya, A Ishikawa, M Deguchi, Y Ohno, T Kawai, T Noguchi
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  ABSTRACT: A novel ethyl methacrylate (EMA) resin was developed to overcome the tissue, organ and systemic damage associated with the residual monomer of conventional methyl methacrylate (MMA) resin bone cement. EMA resin is a chemical/ photopolymerizable material and is easy to handle during clinical procedures. The biocompatibility of EMA was evaluated in accordance with ISO10993-6. No inflammatory response was observed 1 and 9 weeks after implantation in the dorsal subcutaneous tissue of ddY mice. EMA resin also demonstrated better biocompatibility when compared with conventional bone cements. Poly-L-lactic acid (PLLA) was used as a carrier for bone morphogenetic protein (BMP) and added to the EMA slurry. The EMA-PLLA composite membrane was sticky and BMP readily adhered to its surface. The EMA-PLLA-BMP composite membrane induced new bone formation, the new bone growing in the shape of the EMA in the thigh muscle pouch of ddY mice. This novel EMA resin has many potential clinical applications.
  The Journal of international medical research 34(3):256-63. · 0.90 Impact Factor