big-gastrin and Peptic-Ulcer

Topics: Animals; Disease Models, Animal; Gastrins; Gastrointestinal Diseases; Gastrointestinal Neoplasms; Humans; Pancreas; Peptic Ulcer; Protein Precursors

This study evaluates whether a new analytic principle, processing-independent analysis (PIA), offers better specificity and sensitivity than the conventional gastrin radioimmunoassay in the diagnosis of gastrinomas.. Plasma concentrations of alpha-amidated gastrins and the total progastrin product were measured with radioimmunoassay and with PIA, respectively, in 512 samples taken for gastrin measurement and in a selected group of gastrinoma patients (n=10).. Among the 512 patients were 9 with gastrinomas. In plasma from these patients the median degree of amidation (ratio of alpha-amidated gastrins to total progastrin product) was 75% (range, 25-98%), whereas in the other groups the medians varied from 41% to 86%. In the second group of gastrinoma patients all had a degree of amidation of less than 50%.. In screening for gastrinomas PIA offered no diagnostic advantages in comparison with conventional gastrin radioimmunoassay. However, in selected patients who in spite of normal or slightly increased concentrations of amidated gastrins were still suspected of having gastrinoma, additional measurement of the total progastrin product showed incomplete processing of progastrin and thus proved helpful in establishing the diagnosis.

Topics: Anti-Ulcer Agents; Case-Control Studies; Female; Gastrinoma; Gastrins; Humans; Male; Middle Aged; Pancreatic Neoplasms; Peptic Ulcer; Protein Precursors; Radioimmunoassay; Sensitivity and Specificity; Zollinger-Ellison Syndrome

Helicobacter pylori infection is associated with increased meal stimulated gastrin secretion, but the reason for this is unknown. Sequence specific radioimmunoassays were used to measure the concentration of alpha-amidated gastrin, the total progastrin product, and somatostatin in biopsy specimens of human antral mucosa. The antral concentrations of alpha-amidated gastrin and of total progastrin products were significantly higher in H pylori infected patients than in those not infected by this organism. In contrast, the antral somatostatin concentration was significantly decreased in infected patients. Progastrin processing, determined by gel chromatography, seemed unaffected by H pylori infection. The results suggest that the finding of increased gastrin secretion from the antral G cells in H pylori infected patients may be a result of reduced inhibition of G-cell secretion by somatostatin.

Topics: Adult; Aged; Aged, 80 and over; Chromatography, Gel; Dyspepsia; Female; Gastric Mucosa; Gastrins; Helicobacter Infections; Helicobacter pylori; Humans; Male; Middle Aged; Peptic Ulcer; Protein Precursors; Pyloric Antrum; Radioimmunoassay; Somatostatin

Helicobacter pylori infection is associated with exaggerated gastrin release. We investigated whether this abnormality was due to the bacteria or the immune response. Fasting and meal-stimulated 'total' and amidated gastrin were measured in 10 H. pylori-infected volunteers before eradication therapy, after 2 and 14 days of therapy, and 4 weeks after completion of therapy. The exaggerated meal-stimulated gastrin concentration remained unchanged after 2 days of therapy, although the polymorphonuclear cell infiltrate and H. pylori bacteria were no longer evident. The expected fall in gastrin concentration after 14 days of therapy was associated with a reduction in the density of mucosal mononuclear cells, suggesting exaggerated gastrin release was related to chronic inflammation or to H. pylori or its products. The effect of H. pylori on normal progastrin processing was also assessed; 2 control groups were included: 10 H. pylori-uninfected volunteers and 13 patients with H. pylori peptic ulcers. There was a significant difference in the proportion of circulating gastrins that were biologically active amidated gastrins between ulcer patients and uninfected controls (56.7 +/- 4% versus 33.8 +/- 4%, p < 0.001). The proportion of amidated to total gastrins did not increase after successful eradication.

Topics: Adult; Bismuth; Female; Food; Gastrins; Helicobacter Infections; Helicobacter pylori; Humans; Male; Metronidazole; Organometallic Compounds; Peptic Ulcer; Protein Precursors; Protein Processing, Post-Translational; Salicylates; Tetracycline

Topics: Adenocarcinoma; Adult; Aged; Female; Gastric Mucosa; Gastrins; Gastrointestinal Diseases; Humans; Male; Middle Aged; Peptic Ulcer; Peptide Fragments; Protein Precursors; Pyloric Antrum; Stomach Neoplasms