Diagnosis of atrophic gastritis from a serum sample.

On the basis of the levels of serum pepsinogen I (S-PGI) and gastrin-17 (S-G-17) as well as Helicobacter pylori antibodies it is possible to establish with high sensitivity and specificity whether the patient has gastritis, whether the gastritis is atrophic or not and in which part of the stomach the atrophic changes are located. The tests enable the identification of patients whose risk of gastric cancer, consequences of vitamin B12 deficiency or peptic ulcer is increased considerably and who should therefore undergo gastroscopy. They also facilitate diagnosis of non-atrophic Helicobacter gastritis enabling treatment before endoscopy.

Serum levels of amidated gastrin-17 and pepsinogen I in atrophic gastritis: an observational case-control study.

BACKGROUND: Helicobacter pylori infection is often diagnosed with non-endoscopic methods, such as serology or breath or antigen stool tests. These tests provide information on the presence or absence of the H. pylori gastritis only. We investigated whether atrophic gastritis can be diagnosed and typed non-endoscopically if the serum levels of pepsinogen I (S-PGI) and gastrin-17 (S-G-17) are assayed in connection with H. pylori testing. METHODS: The present investigation is an observational case-control study comprising 100 selected dyspeptic outpatients with (cases) or without (controls) advanced (moderate or severe) atrophic gastritis. Before the blood tests, all patients underwent a diagnostic gastroscopy with multiple biopsies. The series of cases includes 56 patients. Eight had an advanced antrum limited atrophic gastritis, 13 had resected antrum (in two of whom the corpus mucosa in the stump was atrophic), and 30 had corpus-limited atrophic gastritis. Four patients had an advanced atrophic gastritis in both the antrum and corpus (multifocal atrophic gastritis), and the whole stomach was removed in one patient. Twenty of the 44 controls had a non-atrophic H. pylori gastritis. Both the antrum and corpus were normal and healthy in 24 patients. The S-PGI and S-G-17 were determined with EIA methods using monoclonal antibodies to PGI and amidated G-17. Postprandial S-G-17 (S-G-17prand) was measured 20 min after a protein-rich drink. The H. pylori antibodies were assayed with a polyclonal EIA method. RESULTS: A low S-PGI (<25 microg/l; an empirical cut-off with best discrimination) was found in 31 of 37 patients (84%) with and in 3 of 63 patients (5%) without corpus atrophy in the biopsy specimens. A low S-G-17prand (<5 pmol/l) was found in all 8 patients with H. pylori-associated antral atrophy and in 11 of 14 patients (79%) with resected antrum but in 3 of 20 control patients (15%) with H. pylori-related non-atrophic gastritis. Median and mean values of both S-G-17prand and S-PGI decreased with increasing grade of antral and corpus atrophy, respectively. Among all patients with atrophic gastritis (multifocal atrophic gastritis, or atrophic gastritis limited to antrum or corpus) or resected stomach, 50 of 56 patients (89%; Cl 95%: 81%-97%) had a low S-PGI and/or a low S-G-17prand with positive H. pylori serology. Such low values werc found in 3 of the 44 control patients (7%; CI 95%: 0%-14%). CONCLUSIONS: Low serum levels of G-17prand and PGI are conceivable biomarkers of atrophic antral and corpus gastritis, respectively. A low S-G-17prand is a sign of the multifocal or antrum-limited atrophic gastritis in patients infected with H. pylori.

Increased risk of developing atrophic gastritis in patients infected with CagA+ Helicobacter pylori.

BACKGROUND: To clarify the possible role of CagA positive (CagA+) Helicobacter pylori strains in the development of atrophic gastritis, the prevalence of antibodies to H. pylori and CagA (120 kD protein) was studied among subjects with atrophic and non-atrophic gastritis. METHODS: The study population was randomly selected among 12,252 Finnish men who were screened for atrophic corpus gastritis with serum pepsinogen I-assay (S-PGI). S-PGI level was used as a selection criterion. Group A consisted of 295 subjects with S-PGI <25 microg/l (low), group B of 320 subjects with S-PGI 25-100 microg/l (normal) and group C of 338 subjects with S-PGI >100 microg/l (high). Antibodies to H. pylori were measured with EIA and immunoblot analysis and antibodies to CagA with immunoblot analysis. Endoscopical and histological examinations were performed for 203 patients from group A. RESULTS: The prevalence of antibodies to H. pylori was significantly lower in group B than in groups A or C (P < 0.0001, chi-squared test). There was a significant association between the prevalence of antibodies to CagA and the lowered level of S-PGI (P < 0.0001, Jonckheere-Terpstra trend test). There was also a linear decrease in the prevalence of antibodies to CagA as the atrophic corpus gastritis became more severe (P < 0.0001, linear-by-linear trend test). CONCLUSION: The presence of antibodies to CagA seems to be associated with development of atrophic corpus gastritis.

Mutascreen, an automated bacterial mutagenicity assay.

Mutascreen is an automated instrument for bacterial mutagenicity testing. The biological principles of the Mutascreen assay are the same as those of the bacterial reverse-mutation assays, like the Ames test, but several operational principles are different. The Mutascreen assay takes place in wells containing only 400 microliter of liquid medium. Also, the dispensing of the liquid medium, the bacterial tester strains, the metabolic activation system (S9), and the test solutions is all performed by a computer-controlled robot according to the user's preprogrammed instructions. The turbidity in up to 200 wells is monitored intermittently over a 24-h period by a vertical-pathway photometer, thereby avoiding measurement problems caused by sedimentation. The data for the resulting growth curves is stored for analysis. The auxotrophic growth pattern is altered characteristically by test solutions that are toxic or contain endogenous growth factor(s), while prototrophic growth is observed earlier in the 24-h period when revertants have been induced by the test solution. To compare the Mutascreen assay with the conventional plate assay, 36 chemicals including known carcinogens and noncarcinogens were tested. Both assays identified the same chemicals as mutagens and gave quantitatively similar results, thus testifying to the potential usefulness of automated bacterial mutagenicity testing.