Developmentally regulated expression of matrix metalloproteinases during fetal rat colon morphogenesis.

To investigate the role of matrix metalloproteinases (MMPs) during gastrointestinal tract development, the expression of gelatinases (MMP-2 and MMP-9) was investigated during fetal rat colon morphogenesis. Fetal rat colons were separated into epithelial and mesenchymal fractions without cross contamination using a chelating agent and a dissecting microscope. Gelatinase activity measured using fluorescently labeled gelatin was higher in the mesenchymal than in the epithelial fraction; the developmental profile revealed that, in both fractions, gelatinase activity was enhanced during colon morphogenesis. During colonic gland formation, there was prominent MMP-2 activity, elevated MMP-2 mRNA expression, and an increase in the level of the active form of MMP-2 in the mesenchymal fraction. The mRNA expression of the tissue inhibitor of metalloproteinase 2 corresponded with an elevation in the level of the active form of MMP-2; the mRNA expression of the cell surface activator of MMP-2, membrane type matrix metalloproteinase 1, did not increase significantly. MMP-9 activity was low; only the pro-form was observed in the epithelial fraction at the end of fetal life. These results suggest that, during colon morphogenesis, MMP activity is under strict spatio-temporal control, and that the activity of MMP-2, which is regulated at both the transcriptional and proteolytic activation levels, is very much involved in rat colon morphogenesis.

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.

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

BACKGROUND AND AIM: A late rise in (13)CO2 excretion in the (13)C-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. METHOD: A total of 143 subjects who were diagnosed as Helicobacter pylori negative by serology, histology and rapid urease test were recruited. At the end of endoscopy, the tip of the endoscope was placed to the second part of the duodenum and 20 mL of water containing 100 mg of (13)C-urea was sprayed into the duodenum. Breath samples were taken at baseline and at 5, 10, 20, 30 and 60 min after administration. RESULTS: Of 143 subjects, breath Delta(13)CO2 values higher than 2.5 per thousand were detected in six (4.2%), four (2.8%) and five (3.5%) subjects at 20, 30 and 60 min, respectively. There was no subject with high Delta(13)CO2 values at 5 and 10 min. Only one subject had an immediate rise at 60 min. CONCLUSION: Variability derived from urease activity in the intestinal tract appears to be minimal up to 60 min after ingestion of the test urea.

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.

Comparison of serum IgA and IgG antibodies for detecting Helicobacter pylori infection.

OBJECTIVE: Although the diagnostic utility of serum IgG antibodies to Helicobacter pylori (H. pylori) is well established, the usefulness of IgA-based tests is less well documented. The aim of this study was to evaluate two commercially available ELISAs, both for IgG and IgA. PATIENTS AND METHODS: Rapid urease test and histology analysis were performed in 183 patients. A patient was considered to be H. pylori-positive when either biopsy test was positive, and considered to be noninfected when both tests were negative. Intestinal metaplasia was determined by dye endoscopy with methylene blue. ELISA testing was performed using the EPI HM-CAP IgG and PP-CAP IgA assays and EIAgen IgG and IgA assays. RESULTS: Sensitivity was 94.7, 93.9, 94.8, and 97.0% for HM-CAP IgG, PP-CAP IgA, EIAgen IgG, and EIAgen IgA, respectively. Although sensitivity was excellent for both IgG and IgA antibodies, specificity of both IgA EIAs was low (PP-CAP 72.6%, EIAgen H. pylori IgA 59.2%). Three of 101 H. pylori-infected patients were PP-CAP positive and HM-CAP negative and four were EIAgen H. pylori IgA positive and EIAgen IgG negative. Of eight noninfected patients in whom intestinal metaplasia was found, PP-CAP IgA results were positive in three of five patients with a HM-CAP IgG negative result and EIAgen IgA was detected in one of four patients with an EIAgen IgG negative result. CONCLUSIONS: Since some patients have IgA positive but IgG negative results, great care should be taken not to underestimate the prevalence of H. pylori infection from the results of IgG serology.