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A technique for determining pepsinogen group I (PGI) concentrations in endoscopic gastroduodenal biopsies is described and validated. This method has a good precision (intra-assay CVs 4.1% to 8.4%; between-assay CVs 4.6% to 9.3%), and analytical recovery is satisfactory (94% to 102%). Results were uninfluenced by the storage interval of the samples. At PGI-producing sites (i.e., fundus, corpus) peptic activity was greater than in the antrum and duodenum. PGI concentrations in serum and in gastroduodenal biopsies were not correlated. This simple, reliable method can quantify better than other assays peptic activity in humans, without being influenced by gastric secretory volumes. It will also facilitate prospective studies on the effect of various secretagogues in vivo and evaluations of the influence of anti-ulcer drugs on peptic secretion.

We assessed selective patterns of histological injury in the gastric mucosa of 25 patients (12 Billroth II, 8 Billroth I, 5 vagotomy and pyloroplasty) with symptoms of alkaline reflux gastritis. Each patient had 12 biopsies taken from standardised sites. Histology was scored separately for surface epithelial changes and for inflammatory cells. The traditional grading of gastritis was also done using the categories of superficial and atrophic gastritis. The main histological changes were epithelial, especially in the pits (foveolae) of Billroth II patients. Although mild to moderate atrophic gastritis was present, the inflammatory cell density was only mild. Differences between surgery types for any given histological parameter became apparent only upon the analysis of regional changes within the stomach. Conventional grading of gastritis is based mainly on degrees of gland loss and thus is mainly of value to study chronic changes. However, the type of histological evaluation used here, with standardised biopsy sites, and separate scoring of epithelial and inflammatory changes is potentially more suitable to study shorter term changes as might occur with cytoprotective or damaging agents.

The appearance of pyloric gland-type cells with a low pepsinogen isozyme 1 (Pg 1) content in the stomach mucosa of F344/Du rats during stomach carcinogenesis was examined by a combination of paradoxical concanavalin A (Con A) staining and immunohistochemical staining for Pg 1. Male F344 rats were given drinking water containing 100 micrograms N-methyl-N'-nitro-N-nitrosoguanidine [(MNNG) CAS: 70-25-7]/ml for 30 weeks and then normal tap water and were killed in week 10, 20, 30, 40, 50, or 70. Untreated rats were killed in week 30 or 70. Serial sections of pyloric mucosa were stained by paradoxical Con A staining and Pg 1 immunostaining. After MNNG treatment, tissues showing changes were classified into normal-looking pyloric mucosa with a low Pg 1 content, mucosa showing atrophic or hyperplastic changes, adenomatous hyperplasia, and adenocarcinoma. From the results of paradoxical Con A staining and Pg 1 immunostaining, the cells in lesions were classified into gastric types (surface mucous cell type and pyloric gland cell type) and intestinal types (intestinal-absorptive cell type and goblet cell type). In this experiment, the cells in lesions were mainly of the gastric cell types. All pyloric glands of control rats in weeks 30 and 70 contained class III mucins and had a high Pg 1 content demonstrated immunohistochemically. After MNNG treatment, class III mucin-positive pyloric glands with a low Pg 1 content in normal-looking pyloric mucosa were found from week 10; subsequently, their number increased with time. Changed mucosa was found from week 20, and the area of cells of the pyloric gland cell type with little or no Pg 1 in changed mucosa was about 30% of the area of cells of the pyloric gland cell type. Adenomatous hyperplasias were found from week 30; adenocarcinomas were found from week 50. Almost all cells of the pyloric gland cell type (greater than 95%) in areas of adenomatous hyperplasia and adenocarcinomas had little or no Pg 1 content. The present results suggested that the appearance of pyloric glands with a low Pg 1 content in normal-looking mucosa might be an immunohistochemically detectable preneoplastic change preceding morphologically detectable preneoplastic changes in stomach carcinogenesis.

Gastric pepsinogens were studied by immunoenzymologic and immunohistochemical methods in non-cancerous adult gastric mucosa, in fetal stomach, and in gastric carcinomas. In noncancerous adult mucosa, immunoenzymologic methods showed that pepsinogen II (previously called Pg I-II) was found mostly in fundic or mediogastric extracts, whereas Pg IV was predominant in antropyloric extracts. Pg II was localized by immunofluorescence techniques in the chief cells of deep glands found near the muscularis. Pg II was localized by immunofluorescence techniques in the chief cells of deep glands found near the muscularis. Pg III was present in the superficial zone of deep glands and Pg IV in the surface epithelium and in the superficial glands of the mucosa. In fetal stomach, only Pg IV (which we called the "fetal pepsinogen") was identified by standard immunoelectrophoresis. It was localized by immunofluorescence in the superficial epithelium. However, bidimensional immunoelectrophoresis and immunofluorescence did reveal low levels of Pg II and Pg III by the 8th or 9th week of ontogenesis. Pg II and Pg III were localized in the rudimentary glands near the superficial epithelium. Important differences were noted when gastric carcinomas were compared with normal mucosa. Pg II or Pg III were often absent in the tumor extracts, but Pg IV was regularly and, at times, exclusively identified regardless of the location of the tumor. By immunofluorescence Pg IV was often the only pepsinogen that was characterized in dedifferentiated cancerous cells; this was also true of the calciform cells of some metaplastic gastric mucosa. Pg III was observed rarely, and Pg II never, in cancerous cells. The biochemical modifications of the cancerous tissue closely resemble those of fetal tissue.

In the mouse stomach exist two acid proteases separable on the polyacrylamide gel electrophoresis. One of them increases in activity after weaning and is a pepsinogen immunologically related to the pepsinogens of other vertebrates. The other is predominant before weaning and is presumed to be a chymosin-like acid protease.

Because it has not been possible to collect gastric lymph by cannulation of lymph vessels, the methods of renal micropuncture were adapted to collection and analysis of 0.5- to 3-mu samples obtained by puncturing lymph vessels on or immediately adjacent to the ventral surface of the dog's stomach. Samples of gastric lymph collected immediately after completion of surgical exposure of the stomach were subjected to acrylamide gel electrophoresis, and they were found to show all the protein bands exhibited by simultaneously collected samples of plasma. Quantitative analysis of similar samples by cellulose acetate electrophoresis gave the following ratios of protein concentration in gastric lymph to plasma: total protein, 0.51; albumin, 0.68; total globulins, 0.42; alpha1-globulin, 0.49; alpha2-globulin, 0.62; beta-globulin, 0.35; fibrinogen, 0.39; and gamma-globulin, 0.46. When samples were collected over 4 hr the concentrations of all proteins in lymph increased, and an argument is presented that this was not the result of increasing small pore size as the result of injury. When the mucosa was irrigated with solutions of dithiothreitol, a substance causing plasma shedding, the concentrations of proteins in gastric lymph over a 4-hr period were similar to those found in control experiments. Gastric lymph mixed with 100 mN HCl was found to have proteolytic activity.

Gastric phenotypic expression indicated by paradoxical concanavalin A (Con A) staining for class III mucins and the immunoperoxidase method for pepsinogen (Pg) I and Pg II was found in pyloric gland metaplasia of gallbladder epithelium. Using the same methods, the features of gallbladder cancers and their relationship to pyloric gland metaplasia in the human gallbladder epithelium were studied. Histologically, 57 gallbladder cancers were classified into 5 papillary adenocarcinomas, 29 tubular adenocarcinomas, 8 poorly differentiated adenocarcinomas, 6 signet-ring cell carcinomas, 4 mucinous adenocarcinomas, and 5 squamous cell carcinomas. In papillary and tubular adenocarcinomas, Pg I and/or Pg II staining was detected in 80% and 75.9% of cancers, respectively. Pg II staining was significantly more frequent than Pg I staining. One signetring cell carcinoma also had Pg II activity. Pyloric gland metaplasias all contained class II mucins and were further classified into complete type and incomplete type on the basis of presence or absence Pg I and/or Pg II activities. A few cancer cells with class III mucins were negative for Pg staining; conversely, a few cells with Pg I and/or Pg II had no class III mucins. Phenotypic diversity in both class II mucin reactivity and Pg activities was observed in gallbladder cancer cells with the pyloric gland cell type. By comparison, pyloric gland metaplasia varied only in Pg activities. A few Pg-positive cancers were found in the gallbladder with Pg-negative pyloric gland metaplasia. The present results clearly indicate the appearance of gastric phenotypic expression in both gallbladder epithelium and gallbladder cancers and suggest the independent induction of pyloric gland metaplasia and cancer with gastric phenotypic expression.

The distribution and time of appearance in the developing human stomach of the 4 aspartic proteinases, pepsinogen, progastricsin, slow-moving protease and cathepsin D, all present in gastric carcinoma, has been determined by the peroxidase-antiperoxidase method on formalin fixed paraffin embedded sections of fetal stomach. Slow-moving protease appears to be the dominant enzyme from 12 weeks gestation onward, although progastricsin is also present at this time. Pepsinogen and cathepsin D do not appear until 17-18 weeks.