Curriculum Vitaes

okubo masaaki

  (大久保 正明)

Profile Information

Affiliation
School of Medicine Faculty of Medicine, Fujita Health University
Degree
医学博士(藤田保健衛生大学)

Researcher number
40623624
J-GLOBAL ID
201501010849502915
researchmap Member ID
7000012755

Misc.

 7
  • Masaaki Okubo, Tomomitsu Tahara, Tomoyuki Shibata, Masakatsu Nakamura, Daisuke Yoshioka, Yoshiteru Maeda, Joh Yonemura, Takamitsu Ishizuka, Tomiyasu Arisawa, Ichiro Hirata
    JOURNAL OF GASTROENTEROLOGY, 46(2) 175-182, Feb, 2011  
    Magnifying narrow-band imaging (NBI) endoscopy visualizes superficial gastric mucosal and capillary patterns. We aimed to investigate changes in gastric mucosal patterns seen by magnifying NBI endoscopy after Helicobacter pylori eradication. Gastric mucosal patterns in non-pathological gastric corpus were observed by magnifying NBI endoscopy before and 12 weeks after H. pylori eradication in thirty patients. By using paired photographs of each case, changes in NBI mucosal patterns during H. pylori eradication were judged in a consensus manner by three blinded endoscopists. At 12 weeks after H. pylori eradication, 20 of 24 subjects who had been successfully treated showed remarkable changes in gastric mucosal patterns (sensitivity 83.3%, specificity 100%). In the specimens from these subjects, the patterns of enlarged or elongated pits were improved to small oval or pinhole-like round pits, and the density of fine irregular vessels was decreased. Histological assessment showed alleviation of chronic inflammation in all subjects (p < 0.0001), while such a change was not observed for four subjects showing severe gastric atrophy and intestinal metaplasia. When the subjects were divided according to the presence of severe gastric atrophy, the diagnostic efficacy of magnifying NBI for predicting the results of H. pylori eradication was excellent in subjects without severe gastric atrophy and intestinal metaplasia (sensitivity and specificity, 100%). However, no change in the NBI mucosal pattern was observed in subjects with severe gastric atrophy and intestinal metaplasia, regardless of the H. pylori eradication result. At least in subjects without severe gastric atrophy or intestinal metaplasia, successful H. pylori eradication treatment shows improvements in gastric mucosal patterns with the use of magnifying NBI endoscopy early after successful treatment.
  • Masaaki Okubo, Tomomitsu Tahara, Tomoyuki Shibata, Hiromi Yamashita, Masakatsu Nakamura, Daisuke Yoshioka, Joh Yonemura, Yoshio Kamiya, Takamitsu Ishizuka, Yoshihito Nakagawa, Mitsuo Nagasaka, Masami Iwata, Hideto Yamada, Ichiro Hirata, Tomiyasu Arisawa
    JOURNAL OF CLINICAL IMMUNOLOGY, 31(1) 69-73, Jan, 2011  
    Common single-nucleotide polymorphisms (SNPs) in microRNAs (miRNA) have been shown to be associated with susceptibility to several human diseases. We evaluated the associations of three SNPs (rs11614913, rs2910164, and rs3746444) in pre-miRNAs (miR-196a2, miR-146a, and miR-499) with the risk of ulcerative colitis (UC) in a Japanese population. The rs11614913 (T > C), rs2910164 (C > G), and rs3746444 (A > G) SNPs were genotyped in 170 UC and 403 control subjects. The rs3746444 AG genotype was significantly higher among the UC group (odds ratio (OR) = 1.51, 95% CI = 1.03-2.21, p = 0.037). The rs3746444 AG genotype was associated with onset at an older age (OR = 1.70, 95% CI = 1.04-2.78, p = 0.035), left-sided colitis and pancolitis (left-sided colitis, OR = 2.10, 95% CI = 1.12-3.94, p = 0.024; pancolitis, OR = 1.81, 95% CI = 1.09-3.01, p = 0.028, left-sided colitis + pancolitis, OR = 1.91, 95% CI = 1.26-2.92, p = 0.003), higher number of times hospitalized (OR = 2.63, 95% CI = 1.22-5.69, p = 0.017), steroid dependence (OR = 2.63, 95% CI = 1.27-5.44, p = 0.014), and refractory phenotypes (OR = 2.76, 95% CI = 1.46-5.21, p = 0.002) while the rs3746444 AA genotype was inversely associated with the number of times hospitalized (2 similar to, OR = 0.36, 95% CI = 0.17-0.79, p = 0.012), steroid dependence (OR = 0.42, 95% CI = 0.21-0.88, p = 0.021), and refractory phenotypes (OR = 0.38, 95% CI = 0.20-0.72, p = 0.003). The rs1161913 TT genotype also held a significantly higher risk of refractory phenotype (T/T vs. T/C + C/C, OR = 2.21, 95% CI = 1.17-4.18, p = 0.016). Our results provided the first evidence that rs3746444 SNP may influence the susceptibility to UC, and both rs3746444 and rs11614913 SNPs may influence the pathophysiological features of UC.
  • Masaaki Okubo, Tomomitsu Tahara, Tomoyuki Shibata, Hiromi Yamashita, Masakatsu Nakamura, Daisuke Yoshioka, Joh Yonemura, Yoshio Kamiya, Takamitsu Ishizuka, Yoshihito Nakagawa, Mitsuo Nagasaka, Masami Iwata, Hideto Yamada, Ichiro Hirata, Tomiyasu Arisawa
    JOURNAL OF CLINICAL IMMUNOLOGY, 31(1) 69-73, Jan, 2011  
    Common single-nucleotide polymorphisms (SNPs) in microRNAs (miRNA) have been shown to be associated with susceptibility to several human diseases. We evaluated the associations of three SNPs (rs11614913, rs2910164, and rs3746444) in pre-miRNAs (miR-196a2, miR-146a, and miR-499) with the risk of ulcerative colitis (UC) in a Japanese population. The rs11614913 (T > C), rs2910164 (C > G), and rs3746444 (A > G) SNPs were genotyped in 170 UC and 403 control subjects. The rs3746444 AG genotype was significantly higher among the UC group (odds ratio (OR) = 1.51, 95% CI = 1.03-2.21, p = 0.037). The rs3746444 AG genotype was associated with onset at an older age (OR = 1.70, 95% CI = 1.04-2.78, p = 0.035), left-sided colitis and pancolitis (left-sided colitis, OR = 2.10, 95% CI = 1.12-3.94, p = 0.024; pancolitis, OR = 1.81, 95% CI = 1.09-3.01, p = 0.028, left-sided colitis + pancolitis, OR = 1.91, 95% CI = 1.26-2.92, p = 0.003), higher number of times hospitalized (OR = 2.63, 95% CI = 1.22-5.69, p = 0.017), steroid dependence (OR = 2.63, 95% CI = 1.27-5.44, p = 0.014), and refractory phenotypes (OR = 2.76, 95% CI = 1.46-5.21, p = 0.002) while the rs3746444 AA genotype was inversely associated with the number of times hospitalized (2 similar to, OR = 0.36, 95% CI = 0.17-0.79, p = 0.012), steroid dependence (OR = 0.42, 95% CI = 0.21-0.88, p = 0.021), and refractory phenotypes (OR = 0.38, 95% CI = 0.20-0.72, p = 0.003). The rs1161913 TT genotype also held a significantly higher risk of refractory phenotype (T/T vs. T/C + C/C, OR = 2.21, 95% CI = 1.17-4.18, p = 0.016). Our results provided the first evidence that rs3746444 SNP may influence the susceptibility to UC, and both rs3746444 and rs11614913 SNPs may influence the pathophysiological features of UC.
  • 柴田 知行, 石塚 隆充, 大久保 正明, 米村 穣, 吉岡 大介, 中村 正克, 平田 一郎
    臨床消化器内科(0911-601X), 26(2) 243-247, Jan, 2011  
  • Masaaki Okubo, Tomomitsu Tahara, Tomoyuki Shibata, Masakatsu Nakamura, Yoshio Kamiya, Daisuke Yoshioka, Yoshiteru Maeda, Joh Yonemura, Takamitsu Ishizuka, Tomiyasu Arisawa, Ichiro Hirata
    DIGESTION, 83(3) 161-166, 2011  
    Combining the narrow-band imaging (NBI) system and magnifying endoscopy allows simple and clear visualization of microscopic structures of the superficial mucosa and its capillary patterns, which may be useful for precise endoscopic diagnosis in the gastrointestinal tract, being more closely to histopathological diagnosis. In the non-neoplastic gastric mucosa, there have been reports showing a potential usefulness of magnifying NBI for the diagnosis of Helicobacter pylori infection, degree of histological gastritis, and intestinal metaplasia. We have shown that magnifying NBI appearances in the non-neoplastic gastric mucosa also predicts pepsinogen levels, which indicates extension of gastric atrophy in the entire stomach, and gastric cancer occurrence. Furthermore, we have shown that magnifying NBI appearances predicts the result of H. pylori treatment. Clear visualization of fine mucosal and capillary patterns, obtained by magnifying NBI, allows prediction of the histological condition, more in detail without biopsy, and it may also be useful for less invasive, and cost-effective endoscopic gastric cancer surveillance, and prediction of H. pylori eradication. Copyright (C) 2011 S. Karger AG, Basel
  • Masaaki Okubo, Tomomitsu Tahara, Tomoyuki Shibata, Hiromi Yamashita, Masakatsu Nakamura, Daisuke Yoshioka, Joh Yonemura, Takamitsu Ishizuka, Tomiyasu Arisawa, Ichiro Hirata
    HELICOBACTER, 15(6) 524-531, Dec, 2010  
    Background: Common single-nucleotide polymorphisms (SNPs) in microRNAs (miRNA) have been shown to be associated with susceptibility to several human cancers. We evaluated the associations of three SNPs (rs11614913, rs2910164, and rs3746444) in pre-miRNAs (miR-196a2, miR-146a, and miR-499) with the risk of gastric cancer (GC) and peptic ulcer diseases, and with the severity of Helicobacter pylori-induced gastritis in Japanese population. Methods: The rs11614913 (C > T), rs2910164 (G > C), and rs3746444 (A > G) SNPs were genotyped in 552 GC, and 697 non-cancer subjects, including 141 gastric and 73 duodenal ulcer, and 483 non-ulcer subjects. The degree of histologic gastritis was classified according to the updated Sydney System, and the serum pepsinogen levels were measured in selected 579 and 204 cases. Results: The rs2910164 CC genotype held a significantly higher risk of GC when compared to non-cancer subjects (adjusted odds ratio (OR) = 1.30, 95% confidence interval (CI) = 1.02-1.66, p =.03). Similarly, the rs2910164 C carrier was associated with higher risk of GC when compared to both non-cancer and non-ulcer subjects (OR = 1.39, 95%CI = 1.00-1.93, p =.05, adjusted OR = 1.57, 95%CI = 1.09-2.27, p =.016, respectively). The rs2910164 CC genotype was associated with non-cardia and upper third, diffuse type and advanced stage GC. The rs11614913 TT genotype was associated with higher degree of mononuclear cell infiltration (score 0-1 vs 2 similar to, adjusted OR = 1.62, 95%CI = 1.05-2.49, p =.03). Conclusions: The rs2910164 (G > C) SNP in the miR-146a is associated with susceptibility to GC. In addition, the rs11614913 (C > T) SNP in the miR-196a2 is associated with the degree of H. pylori-induced mononuclear cell infiltration.
  • 中村 正克, 柴田 知行, 田原 智満, 吉岡 大介, 大久保 正明, 米村 穣, 釜谷 明美, 加藤 祐子, 有沢 富康, 平田 一郎
    消化器医学(1348-7167), 8 39-46, Oct, 2010  

Presentations

 7

教育内容・方法の工夫(授業評価等を含む)

 4
  • 件名(英語)
    -
    概要(英語)
    PBLⅠ(医学部3年)
  • 件名(英語)
    -
    概要(英語)
    基本的診療技能Ⅱ(医学部4年)
  • 件名(英語)
    -
    概要(英語)
    臨床医学総論Ⅰ(臨床工学科2年)
  • 件名(英語)
    -
    概要(英語)
    全体セミナー(クリニカルレクチャー)(医学部5年)