Noriyuki Horiki

Annual Change of Primary Resistance to Clarithromycin among Helicobacter pylori Isolates from 1996 through 2008 in Japan

Background:  Recent studies have shown that the combination of proton pump inhibitor, amoxicillin and clarithromycin is one of the best choices for Helicobacter pylori eradication therapy. However, increasing number of cases of H. pylori infection showing resistance to clarithromycin therapy has been reported and this is currently the main cause of eradication failure. We investigated the annual changes of the antimicrobial susceptibility to clarithromycin, amoxicillin and minocycline during a period of 12 years in Japan.

Reactive nitrogen species mediate DNA damage in Helicobacter pylori-infected gastric mucosa.

Background:  Reactive oxygen species (ROS) and reactive nitrogen species (RNS) can play an important role in cellular injury and carcinogenesis of gastric epithelial cells infected with Helicobacter pylori. 8‐OH‐deoxy guanosine (8‐OHdG) and 8‐nitroguanine (8‐NG) are markers for ROS‐ and RNS‐mediated DNA oxidation, respectively. In this study, RNS‐mediated DNA damage in gastric mucosa was observed directly using a newly developed antibody to 8‐NG to clarify how H. pylori infection causes nitrative DNA damage to gastric epithelial cells.

Evaluation of Recombinant Fragments of Entamoeba histolytica Gal/GalNAc Lectin Intermediate Subunit for Serodiagnosis of Amebiasis

ABSTRACT We have recently identified a 150-kDa surface antigen of Entamoeba histolytica as an intermediate subunit (Igl) of galactose- and N-acetyl-d-galactosamine-inhibitable lectin, which is a cysteine-rich protein consisting of 1,101 amino acids (aa) and containing multiple CXXC motifs in amino acid sequences. In the present study, full-length Igl except for the signal sequences (aa 14 to 1088) and three fragments of Igl—the N-terminal part (aa 14 to 382), the middle part (aa 294 to 753), and the C-terminal part (aa 603 to 1088)—were prepared in Escherichia coli, and the reactivity of these recombinant proteins with sera from patients with amebiasis was examined by means of enzyme-linked immunosorbent assay (ELISA). Sera from 57 symptomatic patients with amebic liver abscess or amebic colitis, sera from 15 asymptomatic cyst passers, sera from 40 individuals with other protozoan infections, and sera from 50 healthy controls were used. The sensitivity and specificity of the recombinant full-length Igl in the ELISA were 90 and 94%, respectively. When three fragments were used as antigens in the ELISA, the sensitivities were 56% in the N terminus, 92% in the middle part, and 97% in the C terminus. The specificities of the three antigens were 96% in the N terminus and 99% in both the middle and C-terminal fragments. These results demonstrate that Igl is well recognized in not only symptomatic but also asymptomatic patients with E. histolytica infection and that the carboxyl terminus of Igl is an especially useful antigen for the serodiagnosis of amebiasis.

ENDOSCOPIC BAND LIGATION WITH A WATER‐JET SCOPE FOR THE TREATMENT OF COLONIC DIVERTICULAR HEMORRHAGE

Although lower gastrointestinal bleeding generally has a less severe course and stops spontaneously in most cases without therapeutic intervention, some patients require endoscopic, surgical, or angiographic treatment depending on the nature of the bleeding. We applied endoscopic band ligation (EBL) with a water‐jet scope to bleeding colonic diverticula and evaluated the efficacy and safety of EBL retrospectively. Five consecutive patients were diagnosed as having colonic diverticular hemorrhage, and were treated with EBL at St Lukes International Hospital in Tokyo from June 2009 to August 2009. Comorbid diseases, usage of anti‐platelet agents, hemoglobin level on admission, procedural time, complications such as perforation and abscess formation, and rebleeding after EBL were retrospectively evaluated. In all cases, EBL achieved successful immediate hemostasis without any procedural complications. In four of five cases, bleeding colonic diverticula were everted after EBL. The mean length of hospital stay after EBL was 5 days (range 4–8 days). No patient exhibited clinical evidence of further bleeding during the mean follow‐up period of 3 months (range 2–4 months), and no further intervention was needed after EBL. EBL with a water‐jet scope is considered to be a safe and effective endoscopic treatment for colonic diverticular hemorrhage.

Reflux esophagitis after eradication of Helicobacter pylori is associated with the degree of hiatal hernia

Background: Several studies have shown that reflux esophagitis (RE) occurs after eradication of Helicobacter pylori. However, endoscopic findings do not allow prediction of the development of RE after successful treatment. In this study, we evaluated the relationship between the prevalence of RE after eradication therapy and the degree of hiatal hernia. Methods: The study comprised 148 patients who had undergone H. pylori eradication therapy over the past 5 years. The degree of RE and hiatal hernia was evaluated based on endoscopic findings. Hiatal hernia was graded according to Hills gastroesophageal flap valve (GEFV; grades I-IV) classification. RE after eradication therapy was graded according to the Los Angeles classification system. H. pylori infection was confirmed in all patients by culture, urease test and histological examination of antral and fundic biopsy specimens. Results: Among 148 patients, there were 122 patients (82.4%) with successful and 26 (17.6%) with failed eradication therapy. RE was diagnosed in 25 (20.5%) out of 122 patients with successful therapy but only in 1 (3.8%) out of 26 patients with failed therapy (P < 0.05). After successful eradication, 25 patients had mild RE (12 with grade A, 13 with grade B). Among patients of the successful eradication group (n = 122), RE was diagnosed in 2 (5.3%) out of 38 patients without hiatal hernia and in 23 (27.4%) out of 84 patients with hiatal hernia (P = 0.0051). Furthermore, RE was diagnosed in 2 (5.3%) out of 38 patients with GEFV grade I, 13 (24.1%) out of 54 with grade II, 7 (30.4%) among 23 with grade III, and 3 (42.9%) out of 7 patients with grade IV. The pH level of gastric juice after eradication therapy was lower in the group with successful eradication than in the group with failed therapy regardless of the incidence and degree of RE. Conclusions: There is a high incidence of RE after successful H. pylori eradication therapy. This incidence of RE was closely associated with the presence and degree of hiatal hernia and with the decrease in gastric juice pH. These findings suggest that the presence of hiatal hernia together with increase in gastric acidity are important determinant factors for the development of RE after successful H. pylori eradication therapy.

Anti‐inflammatory effect of activated protein C in gastric epithelial cells

Summary.  It has been previously demonstrated that activated protein C (APC) plays an important role in the inhibition of inflammation in the gastric mucosa from patients with Helicobacter pylori infection. However, the role of gastric epithelial cells in the anti‐inflammatory activity of APC remains unknown. In the present study, we evaluated the anti‐inflammatory activity of APC and the expression of thrombomodulin (TM) and endothelial protein C receptor (EPCR) in gastric epithelial cells. The gastric epithelial cell lines, MKN‐1 and AGS, and gastric biopsy samples from patients with and without H. pylori infection were used in the experiments. Polymerase chain reaction showed that gastric epithelial cell lines express EPCR and TM. Flow cytometry analysis also showed EPCR expression in both cells. H. pylori infection significantly increased EPCR expression compared with non‐infected cells. Similar results were observed in vivo when samples from patients with and without H. pylori infection were analyzed for EPCR protein expression. Significant TM activity was found on AGS and MKN‐1 cells stimulated with LPS from Escherichia coli and VacA antigen. APC was able to significantly inhibit the secretion of MCP‐1 and IL‐1β induced by H. pylori homogenate in AGS cells. APC also remarkably suppressed the mRNA expression and secretion of MCP‐1 from AGS cells infected with H. pylori. These results demonstrated the expression of components of the protein C pathway on gastric epithelial cells and that APC may play a critical role in the protection against gastric mucosal inflammation.

Human Equilibrative Nucleoside Transporter 1 Expression in Endoscopic Ultrasonography-Guided Fine-Needle Aspiration Biopsy Samples Is a Strong Predictor of Clinical Response and Survival in the Patients With Pancreatic Ductal Adenocarcinoma Undergoing Gemcitabine-Based Chemoradiotherapy.

ObjectivesThis study aimed to clarify whether pretreatment human equilibrative nucleoside transporter (hENT1) expressions in endoscopic ultrasonography-guided fine-needle aspiration biopsy (EUS-FNAB) specimens obtained from resectable, borderline resectable, and locally advanced unresectable pancreatic ductal adenocarcinoma (PDAC) are concordant with those in the resected specimen after gemcitabine-based chemoradiotherapy (Gem-CRT) and to validate the utility of hENT1 expression using EUS-FNAB samples as a prognostic marker. MethodsWe evaluated the relationship between hENT1 expressions assessed by immunohistochemical staining and clinical outcomes in 51 of 76 patients with PDAC who were diagnosed by EUS-FNAB and received preoperative Gem-CRT. ResultsThe concordance rate of hENT1 expressions was 89.2% (K = 0.681). Median survival time (month) in the 51 whole patients and 37 patients with resection was significantly longer in hENT1 positive than in hENT1 negative: 25.0 and 30.0 versus 9.0 and 9.0, respectively. A multivariate analysis confirmed that hENT1 expression was an independent prognostic factor in both whole patients and those with resection. Regardless of T3 and T4, hENT1-positive patients with resection had significantly better prognosis than hENT1-negative patients, whose prognosis was similar to those without resection. ConclusionsThe assessment of hENT1 expression using EUS-FNAB samples before Gem-CRT provides important information on patients with PDAC who can benefit from curative-intent resection.

Second and Third-look Endoscopy for the Prevention of Post-ESD Bleeding

AbstractThe efficacy of 2nd-look esophagogastroduodenoscopy (EGD) with endoscopic hemostatic therapy (EHT) for the prevention of postendoscopic submucosal dissection (ESD) clinical bleeding remains controversial. The aim of this study was to estimate post-ESD bleeding rate using 2nd and 3rd-look strategy, and to determine risk factors for clinical bleeding, and for EHT at 2nd and 3rd-look EGDs.Three hundred forty-four consecutive patients with early gastric cancer or adenoma underwent ESD from January 2006 through March 2012. Second and 3rd-look EGDs were performed on day 1 (D1) and day 7 (D7), respectively, with EHT as needed.Post-ESD clinical bleeding rate was 2.6% (95% confidence interval [CI] 1.2%–4.9%). For clinical bleeding, adjusted odds ratios (ORs) for age <65 years and antithrombotic drug uses were 4.40 (95% CI 1.07–19.93) and 7.34 (95% CI 1.80–32.48), respectively. For D1 EHT, adjusted ORs of tumor location in the lower part of the stomach and maximum tumor diameter ≥60 mm were 2.16 (95% CI 1.35–3.51) and 2.20 (95% CI 1.05–4.98), respectively. For D7 EHT, adjusted OR of D1 EHT was 4.65 (95% CI 1.56–20.0).Post-ESD clinical bleeding rate was relatively low using 2nd and 3rd-look strategy. Age <65 years and antithrombotic drug use are significant risk factors for clinical bleeding. Regarding EHT, tumor location in the lower part of the stomach and maximum diameter of resected specimen ≥60 mm are significant predictors for D1 EHT. D1 EHT in turn is a significant risk factor for D7 EHT. The efficacy of sequential strategy for preventing post-ESD bleeding is promising.

Vacuolating Cytotoxin A is Associated with Increased Thrombin Generation in Gastric Mucosa

Background.  Activation of the coagulation system is a critical response for both the repair of tissue injury and the host defense against microbial pathogens. Activation of the coagulation cascade culminates with the generation of thrombin. In vitro studies have shown that thrombin protects gastric epithelial cells from injury. The present study was undertaken to assess in vivo the relationship between gastric intramucosal generation of thrombin and Helicobacter pylori infection.

Endoscopic findings and lesion distribution in amebic colitis

A retrospective cohort study was conducted in 55 symptomatic patients with amebic colitis that visited at St. Lukes International Hospital and Mie University Hospital from 1994 through 2013. To diagnose amebic colitis, 40 patients underwent total colonoscopy within 1 week after hospital visiting and before receiving any treatment. The percentage of characteristic endoscopic findings of amebic colitis including discrete ulcers or erosions with white or yellow exudates were 0% in terminal ileum, 93% in cecum, 28% in ascending, 25% in transverse, 15% in descending, 20% in sigmoid colon and 45% in rectum. The rectal lesions in 55% of patients with amebic colitis were nonspecific. The trophozoite identification rate by direct smear of intestinal tract washings performed during colonoscopy was 88%. The protozoan identification rate was 70% in biopsy specimens taken from the periphery of the characteristic discrete ulcers. Total colonoscopy should be considered for the diagnosis of amebic colitis.