Katunori Saigenji

Publications of Katunori Saigenji

• Antimicrobial host defense in the upper gastrointestinal tract.

  Authors: Yoshio Hosaka, Maureen Koslowski, Sabine Nuding, Guoxing Wang, Miriam Schlee, Christian Schäfer, Katunori Saigenji, Eduard F Stange, Jan Wehkamp

  European journal of gastroenterology & hepatology. 01/2009; 20(12):1151-8.

  BACKGROUND: With the exception of fungi, microbial infections are rare in the oesophagus. Herein, we aimed to systematically assess the distribution and quantity of different antimicrobial hostBACKGROUND: With the exception of fungi, microbial infections are rare in the oesophagus. Herein, we aimed to systematically assess the distribution and quantity of different antimicrobial host factors as well as, for the first time, functional mucosal antimicrobial activity in the upper gastrointestinal tract. METHODS: We investigated biopsies from the healthy oesophagus, three different locations in the stomach and the duodenum in a total of 12 individuals. Using real-time PCR with external standards, we compared absolute expression of mRNA encoding antimicrobial peptides including defensins, cathelicidin, bactericidal/permeability-increasing protein, psoriasin, and elafin. In addition, we performed immunostaining for human-beta-defensin-1 (HBD1), elafin, and psoriasin. To test functional relevance, we assessed antimicrobial as well as antifungal activity of cationic extracts from biopsies against E. coli ATCC 25922 and a clinical isolate of Candida albicans. RESULTS: In contrast to HBD1 which was similarly expressed in all tissues, inducible beta-defensins in the healthy oesophagus were much higher compared with the stomach and duodenum (for HBD2-4: P<0.01). In addition, the antiproteases elafin and psoriasin were also predominantly expressed in the oesophagus (P<0.005). In contrast, LL-37 and bactericidal/permeability-increasing protein were only marginally expressed. Cationic tissue extracts from both the oesophagus as well as the stomach showed potent antibacterial activity against E. coli. Consistent with susceptibility to Candida infection, the esophageal extracts exhibited a weaker activity against C. albicans (P=0.026). CONCLUSION: Despite dominant expression of antimicrobial host peptides, oesophageal tissue shows a weakened potency to kill C. albicans. These data suggest an important role of yet unknown antimicrobial molecules.

• Use of the restriction enzyme EcoRI for pulsed-field gel electrophoretic analysis of Helicobacter pylori.

  Authors: Yoshio Hosaka, Kazuhiko Irinoda, Ryuichi Nakano, Satosi Tanabe, Wasaburo Koizumi, Katunori Saigenji, Matsuhisa Inoue

  Journal of clinical microbiology. 03/2005; 43(2):931-2.

  Pulsed-field gel electrophoretic (PFGE) analysis of Helicobacter pylori isolates is not commonly employed because of the inability to compare the typing with other typing systems. We adapted the PFGEPulsed-field gel electrophoretic (PFGE) analysis of Helicobacter pylori isolates is not commonly employed because of the inability to compare the typing with other typing systems. We adapted the PFGE analysis for H. pylori by using EcoRI and slightly modified our laboratory methods to improve the typing of isolates (typeability was 97%).

• Characterization of pKU701, a 2.5-kb plasmid, in a Japanese Helicobacter pylori isolate.

  Authors: Yoshio Hosaka, Ryoichi Okamoto, Kazuhiko Irinoda, Satoru Kaieda, Wasaburo Koizumi, Katunori Saigenji, Matsuhisa Inoue

  Plasmid. 06/2002; 47(3):193-200.

  A cryptic plasmid of Helicobacter pylori, pKU701 (accession number AB078638), was isolated and the complete nucleotide sequence was determined. No drug resistance properties were mediated by pKU701.A cryptic plasmid of Helicobacter pylori, pKU701 (accession number AB078638), was isolated and the complete nucleotide sequence was determined. No drug resistance properties were mediated by pKU701. The 2454b pKU701 sequence, which had a 38% content of G-C residues, generated one polypeptide from a single open reading frame (ORF1). Extensive sequence homology was evident between pKU701 and ORF1 of H. pylori plasmid pHPO100 (repA, 88.8% identity) as well as ORF3 of plasmid pHPS1 (repB, 80.2% identity), but pKU701 showed only 46.3% homology with ORF1 of plasmid pHPK255 (repA). Tandem direct repeats of a 33-bp segment were found in pKU701 outside ORF1, but there were no inverted repeat ends such as those found in typical insertion sequences. The ability of drug resistance plasmids to replicate in H. pylori is probably limited, so chromosomal mutation may be a more likely cause of resistance.

• Helicobacter pylori may survive ampicillin treatment in the remnant stomach.

  Authors: Yoshio Hosaka, Ryoichi Okamoto, Kazuhiko Irinoda, Satoru Kaieda, Wasaburo Koizumi, Katunori Saigenji, Matsuhisa Inoue

  The Journal of antibiotics. 06/2002; 55(5):495-8.

  Helicobacter pylori (H. pylori) is a Gram-negative curved rod-like or spiral bacterium that chronically infects the human gastric mucosa, and is a major risk factor for gastritis, gastric andHelicobacter pylori (H. pylori) is a Gram-negative curved rod-like or spiral bacterium that chronically infects the human gastric mucosa, and is a major risk factor for gastritis, gastric and duodenal ulcer and adenocarcinoma of the stomach. After partial gastrectomy, some patients may have persistent H. pylori infection for five years or more. In this study, we detected three bacteria, i.e., Klebsiella pneumoniae, Enterobacter aerogenes, and Escherichia coli, in the gastric juice of patients with a remnant stomach. Some of these bacteria produced beta-lactamase. These findings are potentially important since such bacteria could provide H. pylori with the chance to acquire drug resistance and to transfer drug resistance genes. This could be one reason why H. pylori is difficult to eradicate in the remnant stomach.