Takahiro Wakamatsu

Publications (8)41.81 Total impact

• Article: Excessive length of a tube in the stomach: a risk factor for a tangled or knotted tube.

  Mitsunobu Matsushita, Shigeo Mori, Yoshiya Tahashi, Takahiro Wakamatsu, Kazuichi Okazaki
  Gastrointestinal endoscopy 07/2011; 74(1):237-8; author reply 238. · 6.71 Impact Factor
• Article: Peri-appendiceal red patch and pathogenesis of the appendix in ulcerative colitis.

  Mitsunobu Matsushita, Toshihiro Tanaka, Yuri Fukui, Norimasa Fukata, Takahiro Wakamatsu, Kazuichi Okazaki
  Digestive Diseases and Sciences 07/2011; 56(7):2207. · 2.12 Impact Factor
• Article: A retrograde-viewing device or a transparent hood for improving colorectal adenoma detection.

  Mitsunobu Matsushita, Toshihiro Tanaka, Go Sekimoto, Takahiro Wakamatsu, Naoyuki Danbara, Hiroki Ikeda, Kazuichi Okazaki
  Gastrointestinal endoscopy 03/2011; 73(3):637; author reply 637-8. · 6.71 Impact Factor
• Article: Detection of ileal carcinoid tumor needs further investigations for other lesions.

  Mitsunobu Matsushita, Toshihiro Tanaka, Takahiro Wakamatsu, Naoyuki Danbara, Seiji Kawamata, Hiroki Ikeda, Kazuichi Okazaki
  The American Journal of Gastroenterology 11/2010; 105(11):2508. · 7.28 Impact Factor
• Article: Colonoscopy with a transparent hood: simple technique for improved quality of colonoscopy.

  Mitsunobu Matsushita, Hideo Yamagata, Takahiro Wakamatsu, Naoyuki Danbara, Seiji Kawamata, Mika Omiya, Kazuichi Okazaki
  The American Journal of Gastroenterology 02/2009; 104(2):527. · 7.28 Impact Factor
• Article: Improved polyp detection: narrow-band imaging colonoscopy with a transparent retractable extension device.

  Mitsunobu Matsushita, Takahiro Wakamatsu, Naoyuki Danbara, Mika Omiya, Kazushige Uchida, Akiyoshi Nishio, Kazuichi Okazaki
  The American Journal of Gastroenterology 10/2008; 103(9):2401; author reply 2401-2. · 7.28 Impact Factor
• Article: Complete endoscopic resection of large sessile or flat colorectal polyps with high-magnification chromoendoscopy or endoscopic submucosal dissection.

  Mitsunobu Matsushita, Takahiro Wakamatsu, Naoyuki Danbara, Toshiro Fukui, Takayuki Matsumoto, Mika Omiya, Kazushige Uchida, Kazuichi Okazaki
  Scandinavian Journal of Gastroenterology 09/2008; 43(8):1016-7. · 2.02 Impact Factor
• Article: The combination of glycyrrhizin and lamivudine can reverse the cisplatin resistance in hepatocellular carcinoma cells through inhibition of multidrug resistance-associated proteins.

  Takahiro Wakamatsu, Yoshitsugu Nakahashi, Daisaku Hachimine, Toshihito Seki, Kazuichi Okazaki
  [show abstract] [hide abstract]
  ABSTRACT: Cisplatin is commonly used as a chemotherapeutic agent for hepatocellular carcinoma (HCC). However, it cannot satisfactorily improve the survival rate for patients with advanced HCC due to intrinsic or acquired drug resistance caused by multidrug resistance-associated proteins (MRPs). To clarify whether or not glycyrrhizin and lamivudine have modulator effects on HCC treated with cisplatin, we established a cisplatin-resistant Huh7 HCC cell line and analyzed the mRNA expression of MRPs in the resistant cells. The resistant cells showed 14.1-fold higher resistance to cisplatin, and they expressed higher levels of MRP2 (6.29-fold), MRP3 (3.2-fold), MRP4 (11.3-fold) and MRP5 (3.39-fold) mRNAs than the wild-type cells by using real-time PCR. However, MRP1, MDR1 and GST-pi mRNA were not induced. Compared with the treatment of the resistant cells with cisplatin only, co-treatment with cisplatin and glycyrrhizin or lamivudine significantly decreased the cell viability to 76.8% and 79.5%, respectively. Co-treatment with cisplatin and both glycyrrhizin and lamivudine further decreased the cell viability to 65.1%. Intracellular concentration of cisplatin in the resistant cells decreased to 36.4% of that of the wild-type cells while it increased to 47.7% or 48.4% when glycyrrhizin or lamivudine were added separately, or 60% when they were added together. Our findings indicate the following: i) high expression of MRP2, MRP3, MRP4 and MRP5 decreases cisplatin accumulation in cisplatin-resistant HCC cells and contributes to cisplatin resistance; ii) glycyrrhizin and/or lamivudine accumulate cisplatin in resistant cells by inhibiting the cisplatin efflux from the cells; and iii) glycyrrhizin and lamivudine both act as modulators and have the effect of reversing cisplatin resistance, and co-treatment with glycyrrhizin and lamivudine enhances modulator activity in reversing the cisplatin resistance.
  International Journal of Oncology 01/2008; 31(6):1465-72. · 2.40 Impact Factor