Naotaka Torii

Serum Pepsinogens as a Predicator of the Topography of Intestinal Metaplasia in Patients with Atrophic Gastritis

The importance of atrophic gastritis with intestinal metaplasia is related to the fact that it increases the risk of gastric cancer development. The aim of this study is to evaluate the diagnostic potential of serum pepsinogens in predicting the topography of intestinal metaplasia. Both dye endoscopy and 13C-urea breath test were carried out in 878 subjects. Serum pepsinogen I, pepsinogen II, and IgG antibody to Helicobacter pylori were measured. The overall prevalence of intestinal metaplasia was higher in subjects with lower PG I/II ratios and lower PG I values. Based on ROC curves, a cutoff value for pepsinogen I/II ratio of less than 3.0 would have identified intestinal metaplasia with a sensitivity of 71.7% and a specificity of 66.7% in Helicobacter pylori-positive subjects. It is possible that serum pepsinogens could be used as a screening test for high-risk subjects with intestinal metaplasia.

Efficacy of lactulose plus 13C-acetate breath test in the diagnosis of gastrointestinal motility disorders.

Background:Background: We designed a new method of measuring gastric emptying and orocecal transit time (OCTT) at the same time to assess the influence of gastric emptying upon OCTT. Methods: Twenty-five dyspeptic patients (6 men, 19 women) with a mean age of 64.8 years (range, 25–80 years) were studied. The patients received a liquid test meal, containing 100 mg of 13C-acetate and 12 g of lactulose, while they were in the sitting position after an overnight fast. Breath samples were collected at 10-min intervals of 120 min and both 13CO2 and hydrogen (H2) levels were measured. Subsequently, H2 concentrations were measured at 30-min intervals, for a total of 240 min. Results: The results of gastric emptying were expressed as the time of peak 13CO2 excretion. OCTT was defined as the period between the ingestion of lactulose and a H2 peak rise of 5 ppm above the baseline value. The onset of H2 enrichment in the breath began at 90–110 min, whereas 13CO2 levels increased from the beginning, with peak enrichment values being reached after 60–80 min. OCTT was related to 13CO2 peak time. In 5 of the 25 patients, H2 breath enrichment in the 10-min sample was more than 5 ppm over the baseline value. All these 5 patients had double or triple peaks in serial breath H2 concentrations. Conclusions: The combination of the lactulose hydrogen breath test (LHBT) with the 13C-acetate breath test, which requires only breath samples, provides us with much information on the gastrointestinal tract; gastric emptying, OCTT, bacterial overgrowth in the small intestine, colonic fermentation, and oropharyngeal flora. The 13C-acetate breath test can be useful as an adjuvant test when LHBT is performed for measuring OCTT.

Spontaneous mutations in the Helicobacter pylori rpsL gene

Several studies have revealed that the Helicobacter pylori genome differs markedly from strain to strain, perhaps as a result of mutations arising during persistent infection and/or related to the observed variation in virulence. The development of a detection system for mutations in H. pylori genes might therefore help us to develop a better understanding of its mutability, and in this way help us to develop plans for investigating the relationship between its genomic variability and the pathogenesis of various gastric and duodenal diseases associated with the long-term H. pylori infections. We have therefore begun a study of H. pylori mutability using the endogenous rpsL gene as a marker. Spontaneous mutant frequencies were measured and compared among H. pylori strains, after incubation on plates containing 50 microg/ml of streptomycin for 10 days as a selection procedure. The rpsL gene of each streptomycin-resistant (Str(r)) mutant was amplified by polymerase-chain-reaction (PCR) and sequenced. All of the mutations we characterized were localized at codons 43 or 88 of the rpsL gene and were base transitions from A to G, replacing lysine with arginine. This is in contrast to the spontaneous Str(r) mutants isolated from Escherichia coli, which resulted from either A to G transitions at lysine codons 42 and 87, or A to T or C transversions at lysine codon 42. The spontaneous mutant frequencies of the rpsL gene in H. pylori were of the order of 10(-9), and there were significant differences in spontaneous mutant frequencies among the strains tested. This mutation detection system might be of value in screening clinical isolates for H. pylori mutator phenotypes.

Influence of urease activity in the intestinal tract on the results of 13C-urea breath test

Background and Aim:  A late rise in 13CO2 excretion in the 13C‐urea breath test (UBT) should be found when the substrate passes rapidly through the stomach and makes contact with the colonic bacteria. The aim of this study was to evaluate the influence of intestinal urease activity on the results of the UBT.

High incidence of fermentation in the digestive tract in patients with reflux oesophagitis.

Objectives Because bacteria represent the sole source of gut hydrogen (H2) and methane (CH4), fasting breath H2 and CH4 gases have been used as markers of colonic fermentation. The presence of carbohydrates in the colonic lumen inhibits gastric and pancreatic secretions, and also influences lower oesophageal sphincter function in gastro-oesophageal reflux disease. Materials and methods Studies were performed in 793 consecutive patients undergoing oesophagogastroscopy (270 men and 523 women, aged 19–85 years). A fasting breath sample (20 ml) was collected before endoscopy. At endoscopy, we intubated the stomach without inflation by air, and 20 ml of intragastric gas was collected through the biopsy channel. Next, the tip of the endoscope was inserted into the second portion of the duodenum without inflation by air, and 20 ml of intraduodenal gas was collected. H2 and CH4 concentrations of each sample were measured by gas chromatography. Results Reflux oesophagitis was found in 147 of the 793 patients. The mean values of the H2 and/or CH4 levels of samples taken from the stomach, duodenum and exhaled air were higher in patients with reflux oesophagitis than those without reflux oesophagitis. High H2 and/or CH4 levels were more frequently found in patients with reflux oesophagitis. Conclusions We concluded that the presence of fermentation in the digestive tract was considered to be a risk factor for developing reflux oesophagitis.

Endoscopic 13C-Urea Breath Test for Detection of Helicobacter Pylori Infection After Partial Gastrectomy

BACKGROUND/AIMS It is difficult to interpret the results of 13C-urea breath test (UBT) in gastrectomy patients because the test urea may pass through the stomach faster. The aim of this study is to evaluate the efficacy of the modified endoscopic UBT for detection of Helicobacter pylori (H. pylori) infection in the residual stomach. METHODOLOGY An endoscopic UBT was performed in 44 patients who had undergone partial gastrectomy. At endoscopy, 20 mL of water containing 100mg of 13C-urea were sprayed onto the gastric mucosa and an intragastric gas sample was immediately collected through the biopsy channel. Breath samples were collected at 20 min after spraying 13C-urea. RESULTS The intragastric delta13CO2 value in H. pylori-positive patients was significantly higher than those of 20-minute breath samples. The maximum sensitivity and specificity of intragastric samples were 97% and 100% with cutoff point of 5 per thousand, respectively. The sensitivity and specificity of breath samples at 20 min were 71.4% and 66.7% with cutoff point of 0.6 per thousand, respectively. CONCLUSIONS An endoscopic UBT was superior to a standard UBT to detect H. pylori infection after partial gastrectomy.

Ten-Second Endoscopic Breath Test Using a 20-Mg Dose of 13c-Urea to Detect Helicobacter Pylori Infection

BACKGROUND/AIMS Attempts to improve the 13C-urea breath test (UBT) have focused on decreasing the amount of substrate used and reducing the duration of the test. To render the test less expensive and more convenient, we designed a more rapid and less expensive endoscopic UBT with a low dose of 20 mg and a shortened measurement time. METHODOLOGY A total of 178 patients who underwent diagnostic upper endoscopy were enrolled. At endoscopy, 150 mL of intragastric gas sample were collected through a biopsy channel. Following inflation with air, 20 mL of water containing 20 mg of 13C-urea were sprayed onto the gastric mucosa using a spraying instrument. After 10 seconds, a gastric gas sample was collected again. The standard UBT was performed after 3-10 days. RESULTS The delta13CO2 values of intragastric samples in H. pylori-positive patients and H. pylori-negative patients were 76.7 +/- 132.9 per thousand and 1.6 +/- 1.2 per thousand, respectively. With intragastric samples, the maximum sensitivity and specificity of intragastric samples were 83.7% and 100% with cut-off point of 8 per thousand, respectively. CONCLUSIONS Ten-second endoscopic UBT using a 20-mg dose of 13C-urea is a rapid, inexpensive, and accurate method for the detection of H. pylori infection in clinical practice.

Hydrogen breath test as an indicator of the quality of colonic preparation for colonoscopy

BACKGROUND Breath hydrogen levels after ingestion of polyethylene glycol were evaluated as a method of predicting the quality of colonic preparation. METHODS One hundred patients undergoing nonemergency colonoscopy were recruited for this study. After fasting overnight, they were instructed to ingest a polyethylene glycol solution containing 12 g lactulose at a rate of 50 mL every 5 minutes for 2 hours. During ingestion of the polyethylene glycol solution, breath samples were taken at 15-minute intervals for 240 minutes and breath hydrogen concentration was measured. RESULTS The preparation for colonoscopy was judged to be poor in 18% and adequate in 82%. The breath hydrogen levels over 90 minutes were significantly higher in the poor group than in the adequate group. In all patients with a breath hydrogen level less than 10 parts per million at 240 minutes, the preparation was adequate. Conversely, all patients with a poor preparation had a breath hydrogen level of more than 10 ppm at 240 minutes. CONCLUSIONS The hydrogen breath test effectively predicts adequacy of colonic preparation.