The Distribution of Helicobacter pylori in Human Gastric Mucosa in vivo

The relationship between gastric juice nitrate/nitrite concentrations and gastric mucosal surface pH

PURPOSE

To investigate gastric juice nitrate/nitrite concentration according to mucosal surface pH extent (area) of gastric corpus intimately contacting the gastric juice.

MATERIALS AND METHODS

We included ninety-nine patients with dyspepsia. To evaluate gastric mucosal surface pH and its extent, gastric chromosocpy was performed by spraying phenol red dye on the corpus mucosa and estimating the extent of area with color changed. Nitrate/nitrite concentrations and pH of gastric juice were measured by ELISA and pH meter, respectively. Silver staining was done to histologically confirm the presence of Helicobacter pylori.

RESULTS

Intragastric nitrate/nitrite concentrations in patients, showing phenol red staining mucosa were higher than those of unstaining mucosa (p=0.001): the more extensive in the area of phenol red staining area of corpus, the higher gastric juice pH found (r=0.692, p<0.001). Furthermore, the intragastric nitrate/nitrite concentrations correlated positively with gastric juice pH (r=0.481, p<0.001).

CONCLUSION

The changes of mucosal surface pH and its extent in gastric corpus might affect either pH or nitrate/nitrite level of gastric juice.

Comparison of the 13C-urea breath test and the endoscopic phenol red mucosal pH test in the quantification of Helicobacter pylori infection loading

BACKGROUND/AIMS

The (13)C-urea breath test (UBT) is a semiquantitative test for measuring Helicobacter pylori infection loading. H. pylori produces ammonia, which elevates the pH of the gastric mucosa and is detectable via endoscopy using a phenol red indicator. We evaluated whether this test could be used to diagnose H. pylori infection and whether phenol red staining was correlated with (13)C-UBT results.

METHODS

One hundred and twenty-three patients participated. The UBT was performed after ingestion of a capsule containing urea. A change in (13)C-UBT >2 ppt was selected as the cutoff value for diagnosing infection. After spraying evenly with a 0.1% phenol red solution, the pH of the gastric mucosal surface was measured using an antimony electrode through the biopsy channel.

RESULTS

The pH of stained mucosa (6.9+/-0.4) was significantly higher than that of unstained mucosa (1.9+/-0.8; p<0.001), and the H. pylori detection rate confirmed via histology was higher in stained versus unstained mucosa (p<0.01). Extensive mucosal staining resulted in a higher detection rate (p<0.001). The UBT produced results were very similar to those obtained via histological detection in stained mucosa (p<0.001). The extent of staining, expressed as a staining score, was positively correlated with the change in (13)C-UBT (r=0.426, p<0.001). A significant correlation was also observed between the histologically determined H. pylori density and (13)C-UBT results (r=0.674, p<0.001).

CONCLUSIONS

H. pylori infection elevates gastric mucosal surface pH, and endoscopic phenol red staining may be an alternative method for the diagnosis of H. pylori infection.

Delta (13)C-urea breath test value is a useful indicator for Helicobacter pylori eradication in patients with functional dyspepsia

BACKGROUND

Eradication of Helicobacter pylori is not routinely recommended for the symptomatic relief and the prevention of gastric cancer in patients with functional dyspepsia. The present study investigated a useful indicator of H. pylori eradication in such patients by determining the optimal cutoff value of a 13C-urea breath test (UBT).

METHODS

One hundred dyspeptic patients participated in the study. Dyspepsia was scored, and a 13C-UBT administered. A level of delta 13C-UBT of>4 per thousand was diagnosed as H. pylori-positive. After the stomach was endoscopically sprayed with phenol red, biopsy specimens were taken from the antrum, body and cardia of the stomach for the assessment of H. pylori density, and activity (neutrophil infiltration) and degree (lymphocyte infiltration) of gastritis.

RESULTS

Correlation between delta 13C-UBT and dyspepsia score was not found. Delta 13C-UBT significantly correlated with H. pylori density score in the total stomach (r = 0.53, P < 0.0001), neutrophil (r = 0.34, P = 0.0005) and lymphocyte score (r = 0.69, P < 0.0001). Twenty-six of the 100 subjects had a neutrophil score of >or=4, lymphocyte score of >or=4, and H. pylori score of >or=4. Their 95% confidence interval of mean was 58.2 per thousand, which reflects moderate to marked acute and chronic gastritis, and dense H. pylori colonization.

CONCLUSIONS

The 13C-UBT is a reliable semiquantitative test to assess H. pylori density and the activity and degree of gastritis. It is proposed that H. pylori eradication therapy might be beneficial for patients with functional dyspepsia with a delta 13C-UBT of >58.2 per thousand.

Endoscopic [13C]-urea breath test for quantification of Helicobacter pylori infection

BACKGROUND

We previously developed a new diagnostic method for Helicobacter pylori infection and called it the endoscopic [13C]-urea breath test (EUBT). Here we evaluate the relationship between the EUBT results and the histological findings.

METHODS

The EUBT was performed on 137 patients with gastroduodenal diseases. After the collection of a baseline breath sample, gastroduodenal endoscopy was performed. Twenty milliliters of 0.05% phenol red solution containing 100 mg of [13C]-urea was sprayed over the entire gastric mucosa under endoscopic observation. A breath sample was collected 15 min after spraying. The content of 13CO2 in the breath samples was measured by ratio mass spectrometry. Two biopsy specimens each from the antrum and the middle corpus were obtained for culture and histology. Helicobacter pylori colonization, activity, inflammation, atrophy and intestinal metaplasia were classified on a four-point scale according to the Updated Sydney System.

RESULTS

We found positive correlations between the EUBT values and the H. pylori colonization and activity score in the antrum and corpus, and negative correlations between the EUBT values and the atrophy and intestinal metaplasia scores in the corpus.

CONCLUSIONS

The EUBT can be an indicator of the intragastric bacterial load and the histological findings for H. pylori.

Diagnosis of Helicobacter pylori infection

A number of diagnostic tests have been developed for the detection of H. pylori. Diagnostic techniques can be divided into invasive and noninvasive methods. The invasive methods require upper gastrointestinal endoscopy and involve culture of gastric biopsy specimens, examination of stained biopsies and detection of urease activity in the biopsies themselves. In addition, we have developed endoscopic diagnosis of H. pylori infection in gastric mucosa using phenol red dye-spraying. The noninvasive methods include urea breath test and serological techniques. Although there has been considerable improvement in the techniques, a combination of at least two different techniques should be used in order to optimize the diagnostic yield. We recommend the use of one rapid test in the combination. The rapid urease test, cytology and the phenol red dye-spraying endoscopy give results available before the patient leaves the endoscopy suite.

Significance of rapid urease test for identification of Helicobacter pylori in comparison with histological and culture studies

Helicobacter pylori in the stomach is an etiological factor of gastritis and peptic ulcer. It is now considered that gastric cancer can be, at least in some cases, a late complication of H. pylori infection. In 123 consecutive endoscopic antral biopsies obtained from patients with the Okamoto Hospital, the specimens were subjected to the rapid urease test (RUT), histology (H&E stain), and culture, for the identification of H. pylori. The results of these methods were compared semi-quantitatively in order to evaluate these detection methods for identifying H. pylori. The results of these methods were found to agree well, with the Spearman's rank correlation coefficient between RUT and culture being 0.90 (P < 0.01) and that between histology and culture being 0.80 (P < 0.01). RUT is considered to be a very simple, sensitive, and highly specific test which enables the endoscopist to diagnose H. pylori infection.