Ichiro Imoto

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.

Lactoferrin inhibits hepatitis C virus viremia in chronic hepatitis C patients with high viral loads and HCV genotype 1b

carcinoma have been reported during the past 16 yr. The time interval between fine-needle aspiration/biopsy and recurrence has varied from as early as 3 wk to as late as 4 yr. Needle diameter, number of passes, and the surrounding liver parenchyma are the factors influencing the rate of recurrence (2). The risk of needle tract recurrence of liver tumor should be regarded as significant, especially in patients with small hepatocellular carcinoma for whom long term survival is expected after surgical resection or orthotopic liver transplantation (3). Hence, the role of needle biopsy in confirming hepatocellular carcinoma needs critical evaluation. It should possibly be reserved for cases not amenable to surgical resection or where hepatocellular carcinoma cannot be diagnosed with noninvasive imaging modalities and -fetoprotein levels.

Lactoferrin sequestration and its contribution to iron‐deficiency anemia in Helicobacter pylori‐infected gastric mucosa

Background and Aim:  It is known that lactoferrin serves as a source of iron for Helicobacter pylori in gastric mucosa. The present study was undertaken to investigate the relationship between lactoferrin and H. pylori infection coexistent with iron‐deficiency anemia by determining the lactoferrin levels in gastric biopsy specimens, and by locating the major sites of lactoferrin expression, according to the presence or absence of iron‐deficiency anemia.

Ease of early gastric cancer demarcation recognition: A comparison of four magnifying endoscopy methods

Background and Aim:  Various techniques using magnifying endoscopy (ME) have been developed to enhance images of early gastric cancer (EGC) demarcations, which are often obscure. We investigated four ME methods to determine which is most effective in enhancing the recognition of EGC demarcations: conventional ME (CME), ME with narrow band imaging (NBI‐ME), enhanced‐magnification endoscopy with acetic acid (EME), and ME with NBI and acetic acid (NBI‐EME).

Features of early gastric cancer and gastric adenoma by enhanced-magnification endoscopy

BackgroundChanges to the mucosal surface of early gastric carcinomas and gastric adenomas as viewed by enhanced-magnification endoscopy with acetic acid have not been investigated thoroughly. Using this technology, we investigated the appearance of the gastric surface patterns of neoplastic and surrounding nonneoplastic mucosa.MethodsForty-seven consecutive patients with early gastric carcinomas or gastric adenomas underwent enhanced-magnification endoscopy following 1.5% acetic acid instillation. All biopsy specimens were taken from the area at which the enhanced-magnified endoscopic image was obtained.ResultsSurface patterns of gastric tumors and the surrounding mucosa were classified into five types: type I, small round pits of uniform size and shape; type II, slit-like pits; type III, gyrus and villous patterns; type IV, irregular arrangements and sizes of pattern types I, II and III; type V, destructive patterns of types I, II and III. The predominant pattern of the surrounding mucosa was type III, and most type III mucosa had characteristics of intestinal metaplasia. Although all elevated adenomas showed type II or type III surface patterns, both depressed adenomas showed type IV. Elevated carcinomas showed type III (42.9%) or type IV (57.1%) surface patterns, while depressed carcinomas showed type IV (70%) or type V (30%). Although differentiated tubular adenocarcinomas showed type III (10.3%), type IV (86.2%), or type V (3.5%) surface patterns, all of the signet-ring cell carcinomas and poorly differentiated tubular adenocarcinomas showed type V.ConclusionsEnhanced-magnification endoscopy may be useful for identifying gastric tumors and determining the extent of horizontal spread, especially in tumors of the depressed type.

Effect of lactoferrin in patients with chronic hepatitis C: Combination therapy with interferon and ribavirin

Objectives:  Lactoferrin has been reported to inhibit hepatitis C virus (HCV) infection in cultured human hepatocytes and HCV viremia in patients with chronic hepatitis C (CHC). The aim of this study was to evaluate the effect of combined triple therapy of lactoferrin, interferon and ribavirin in patients with CHC.

Gastric Juice Levels of Lactoferrin and Helicobacter pylori Infection

BACKGROUND Recently, in vitro studies suggested that lactoferrin (Lf) might play an important role in the physiopathology of Helicobacter pylori-associated gastritis. However, whether Lf is present in the gastric juice and its relationship with H. pylori infection have not as yet been reported. In the present investigation the presence of Lf in gastric juice and its correlation with H. pylori infection were assessed. METHODS This study comprised 30 H. pylori-positive and 14-negative patients with chronic gastritis. Gastric juice levels of Lf were measured with enzyme-linked immunoassays. Gastric juice concentration of Lf was also investigated in accordance with the histologic findings of biopsy specimens in the gastric body and antrum. RESULTS Lf concentration in gastric juice was significantly higher in H. pylori-positive than in -negative patients (P = 0.033). The pH values are known to influence the levels of Lf. However, intragastric Lf levels were also significantly increased in H. pylori-positive patients as compared with H. pylori-negative patients after correcting the Lf levels for pH values (P = 0.029) or after adjusting the pH values of the gastric juice with NaHCO3 solution in both groups of patients (P = 0.0007). In addition, the gastric juice levels of Lf correlated significantly with the gastric mucosal concentrations of Lf in the gastric body (P < 0.005, r = 0.568) and the antrum (P < 0.05, r = 0.401). CONCLUSIONS This study showed for the first time that Lf is present in gastric juice and that it correlates with H. pylori infection. Lf may constitute a good marker for H. pylori-associated gastritis. Although correlation does not prove causation, this study suggests that Lf might play an important role in the physiopathology of H. pylori-associated gastritis.

Surface pattern classification by enhanced-magnification endoscopy for identifying early gastric cancers

BACKGROUND The correlation between fine surface patterns of gastric mucosal lesions and early gastric cancer is not sufficiently clear. OBJECTIVE To evaluate the efficacy of surface pattern classification by enhanced-magnification endoscopy (EME) for identifying early gastric cancers. DESIGN Observational study. SETTING All procedures were performed at Mie University Hospital. PATIENTS A total of 380 consecutive patients who underwent EGD by using magnification endoscopy. Among these subjects were found 250 newly detected lesions suspected of being gastric cancer. METHODS Conventional magnification endoscopy (CME), magnification chromoendoscopy (MCE), and EME were performed, and surface patterns of lesions were classified into 5 types: type I, small round pits of uniform size and shape; type II, slit-like pits; type III, gyrus and villous patterns; type IV, irregular arrangement and size; and type V, destructive pattern. Biopsy specimens were obtained from all lesions. MAIN OUTCOME MEASUREMENTS Correlation between surface pattern classification by EME and histopathologic findings of early gastric cancer. RESULTS Surface patterns were evident by CME/MCE in only 66.4% (166/250) of lesions but in 100% (250/250) of lesions by EME. Classification by EME was as follows: type I, 52 lesions; type II, 12; type III, 146; type IV, 32; and type V, 8. By histopathologic examination, 16 early gastric cancers were detected between type IV or V lesions. Thus, classification of types IV-V strongly correlated with the presence of gastric cancer (sensitivity 100%, specificity 89.7%). LIMITATIONS Single-center study. CONCLUSIONS Surface pattern classification by EME may be useful for identifying early gastric cancers.

Susceptibility of Helicobacter pylori and its urease activity to the peroxidase-hydrogen peroxide-thiocyanate antimicrobial system

The susceptibility of Helicobacter pylori to the antimicrobial system involving lactoperoxidase, hydrogen peroxide and thiocyanate was investigated. The inhibitory effect of the system on the urease activity of H. pylori, which plays a role in its colonisation of the stomach, was also investigated. Twelve H. pylori strains examined, including 10 clinical isolates, were all inhibited by the peroxidase system in brain-heart infusion broth supplemented with fetal calf serum, but to different extents. The killing effect was observed within 3 h. Although bacterial viability recovered afterwards, there was still a clear difference between cultures incubated in the presence of the complete system and control cultures incubated in the absence of lactoperoxidase, after incubation for 24 h. The urease activity and viability of H. pylori were both inactivated by this system in phosphate buffer. These effects were dependent on the concentrations of both lactoperoxidase and hydrogen peroxide and were abolished by the addition of cysteine. Furthermore, these effects were observed when bovine lactoperoxidase was replaced by recombinant human lactoperoxidase or native or recombinant human myeloperoxidase. The peroxidase system found in saliva and milk may contribute to the host defence against H. pylori infection and inhibition of transmission via the oral route.

Helicobacter pylori infection in patients with gastric carcinoma in biopsy and surgical resection specimens

The discrepancy between the high seropositivity for Helicobacter pylori (H. pylori) and the low diagnostic yield of H. pylori organism in gastric biopsies of patients with gastric carcinoma has yet to be clarified. The present study attempted to clarify this controversial point by performing a comparative evaluation between the detection rate of H. pylori in biopsy and in surgical specimens.