Peptic ulcer: the many proteinases of aggression

Assessing peptic ulcer risk with the HAMPROW score in the general Chinese population

The timely identification of individuals at high risk for peptic ulcers (PUs) is vital in preventing gastrointestinal bleeding after antiplatelet therapy. This study was designed to determine PU risk factors and develop a risk assessment model for PU detection in the general Chinese population. In a prospective dataset, clinical data from individuals undergoing gastroscopic evaluation between April 2019 and May 2022 were recorded. PUs were defined as mucosal defects exceeding 5 mm confirmed via gastroscopy. Participants were categorized into development (April 2019 to April 2021) and validation (May 2021 to May 2022) sets based on chronological order. LASSO-derived logistic regression analysis was employed to create a score, which was further validated via temporal validation. A total of 902 patients were ultimately enrolled, 204 (22.6%) of whom had PUs based on endoscopic findings. In the development cohort (n = 631), seven independent risk factors emerged: male sex (OR = 2.35, P = 0.002), white blood cell (WBC) count (OR = 1.16, P = 0.010), red blood cell (RBC) count (OR = 0.49, P < 0.001), globulin level (OR = 0.92, P = 0.004), albumin level (OR = 0.94, P = 0.020), pepsinogen I (PGI) level (OR = 1.01, P < 0.001), and positive Helicobacter pylori (HP) antibody (OR = 2.50, P < 0.001). Using these factors, a nomogram (HAMPROW score [hazard ratio (HP) antibody, albumin, male, PGI, RBC, globulin, and WBC]) was developed for individual PU prediction. The ability of the HAMPROW score to predict survival was confirmed with AUCs of 0.854 (95% CI 0.816-0.891) and 0.833 (95% CI 0.771-0.895) in the development and validation sets, respectively. In conclusion, the HAMPROW score can be used to screen for PUs effectively in the general Chinese population, facilitating personalized early detection of high risk of gastrointestinal bleeding before antiplatelet therapy.

Activation of dopamine D2 receptor promotes pepsinogen secretion by suppressing somatostatin release from the mouse gastric mucosa

In vivo administration of dopamine (DA) receptor (DR)-related drugs modulate gastric pepsinogen secretion. However, DRs on gastric pepsinogen-secreting chief cells and DA D2 receptor (D2R) on somatostatin-secreting D cells were subsequently acquired. In this study, we aimed to further investigate the local effect of DA on gastric pepsinogen secretion through DRs expressed on chief cells or potential D2Rs expressed on D cells. To elucidate the modulation of DRs in gastric pepsinogen secretion, immunofluorescence staining, ex vivo incubation of gastric mucosa isolated from normal and D2R-/- mice were conducted, accompanied by measurements of pepsinogen or somatostatin levels using biochemical assays or enzyme-linked immunosorbent assays. D1R, D2R, and D5R-immunoreactivity (IR) were observed on chief cells in mouse gastric mucosa. D2R-IR was widely distributed on D cells from the corpus to the antrum. Ex vivo incubation results showed that DA and the D1-like receptor agonist SKF38393 increased pepsinogen secretion, which was blocked by the D1-like receptor antagonist SCH23390. However, D2-like receptor agonist quinpirole also significantly increased pepsinogen secretion, and D2-like receptor antagonist sulpiride blocked the promotion of DA. Besides, D2-like receptors exerted an inhibitory effect on somatostatin secretion, in contrast to their effect on pepsinogen secretion. Furthermore, D2R-/- mice showed much lower basal pepsinogen secretion but significantly increased somatostatin release and an increased number of D cells in gastric mucosa. Only SKF38393, not quinpirole, increased pepsinogen secretion in D2R-/- mice. DA promotes gastric pepsinogen secretion directly through D1-like receptors on chief cells and indirectly through D2R-mediated suppression of somatostatin release.

The Impact of Gastric Juice pH on the Intraluminal Therapy for Helicobacter pylori Infection

Background: Helicobacter pylori (H. pylori) can be topically eradicated in stomach lumen on endoscopic examination. The procedures of intraluminal therapy for H. pylori infection (ILTHPI) include the control of intragastric pH, mucolytic irrigation of the gastric mucosal surface, and a single-dose medicament containing antimicrobial agents. Aims: To detect gastric juice pH and evaluate its impact on the success rate of ILTHPI. Methods: We enrolled 324 patients with upper abdominal discomfort for endoscopic examinations. Among them, 13C-urea breath test was positive in 218 patients, where 100 underwent ILTHPI, and negative in 106. All patients had their gastric juice pH detected and set into three ranges, including normal acidity (pH < 4.0), low-level hypoacidity (pH 4.0–5.5), and high-level hypoacidity (pH ≥ 6.0). The impact of gastric juice pH on the success rate of ILTHPI was evaluated. Results: Distribution of pH level showed no significant difference between two groups of H. pylori-infected patients (p = 0.942). The eradication rate of ILTHPI is significantly lower in patients with gastric juice pH below 4 (p < 0.001). Conclusions: Detection of gastric juice pH in ILTHPI is extremely important. Rapid control of stomach pH at or above 4 for patients prior to ILTHPI is strongly recommended. (NCT03124420).

Non-invasive method for the assessment of gastric acid secretion

Methods for the measure of gastric acid secretion include invasive and non-invasive tests. The gold-standard to measure the acid output is the collection of gastric after in basal condition (Basal Acid Output, B.A.O.) and after an i.m. injection of pentagastrin (Maximal Acid Output, M.A.O.). However, direct measurement of gastric acid production is out of order in clinical practice, but many GI symptoms are claimed to be related with acid disorders and empirically cured. Hypochlorhydria is associated with precancerous conditions such as chronic atrophic gastritis (CAG). Acid measurement with non-invasive methods (pepsinogens) is supported by international guidelines.

Colorectal cancer after negative colonoscopy in fecal immunochemical test-positive participants from a colorectal cancer screening program

Background and study aims  Colorectal cancer (CRC) risk after a positive fecal immunochemical test (FIT) and negative colonoscopy is unknown. We aimed to ascertain the cumulative incidence of post-colonoscopy colorectal cancer (PCCRC) and the manifestation of other lesions that could explain the test positivity in individuals with a negative colonoscopy in a population screening program. Patients and method  Observational study in participants from the first round of a CRC screening program (2010 - 2012) with positive-FIT (≥ 20 μg/g of feces) and negative colonoscopy (without neoplasia). A 42- to 76-month follow-up was performed searching in the National Health Service database and by a brief structured telephonic interview. Results  Of 2659 FIT-positive individuals who underwent colonoscopy, 811 (30.5 %) had a negative colonoscopy. Three PCCRC (0.4 %) were detected within 11 - 28 months and accelerated carcinogenesis was ruled out. Among those with normal colonoscopy, 32 (5 %) relevant lesions were detected at follow-up. One-third of them (11/32) were significant neoplasias: a gastric cancer, a small-bowel lymphoma, six advanced colorectal adenomas, and the three PCCRC. The 21 remaining lesions were inflammatory, vascular disorders, or non-advanced colorectal adenomas. Conclusions  The vast majority (95 %) of individuals did not present any subsequent lesion that could explain the FIT positivity. The very low incidence (0.4 %) and characteristics of PCCRC observed in our cohort reinforce the concept that, although a positive FIT preselects high risk individuals, a high quality colonoscopy is the paramount factor in preventing PCCRC. Improving quality standards of colonoscopy are required to strengthen the current CRC screening strategies.

Esophageal Dysmotility, Gastro-esophageal Reflux Disease, and Lung Transplantation: What Is the Evidence?

Lung transplantation is an effective and life-prolonging therapy for patients with advanced lung disease (ALD). However, long-term patient survival following lung transplantation is primarily limited by development of an inflammatory and fibrotic process involving the lung allograft known as bronchiolitis obliterans syndrome (BOS). Although the precise cause of BOS remains uncertain and is likely multifactorial, chronic aspiration of gastro-duodenal contents is one possible contributing factor. Multiple small, cross-sectional studies performed over the past two decades have reported a high prevalence of gastro-esophageal reflux disease (GERD) and esophageal dysmotility in the ALD population and several investigations suggest the prevalence may increase following lung transplantation. More recent studies evaluating the direct effect of gastro-duodenal contents on airways have demonstrated a possible biologic link between GERD and BOS. Despite the recent advances in our understanding of BOS, further investigations are needed to establish GERD as a causative factor in its development. This review will discuss the existing literature that has identified an association of GERD with ALD and post-transplant populations, with a focus on recent advances in the field.

Chicken and rabbit antibodies against porcine pepsinogen A

Isolated porcine pepsinogen A was used for the preparation of polyclonal rabbit and polyclonal chicken anti-pepsinogen A antibodies. Immunochemical properties of both immunoglobulin fractions were compared. The rabbit anti-serum was further purified using immobilized porcine pepsinogen A on magnetic cellulose beads and the resulting anti-pepsinogen A fraction proved to be applicable for the separation and the determination of porcine pepsinogen A. In contrary, antibodies prepared from chicken eggs by the same way have been found not suitable for the evaluation of the pepsinogen A level. Unexpectedly, the pre-immune fraction of chicken antibodies showed reactivity against porcine pepsinogen A and the affinity separation of specific polyclonal chicken anti-pepsinogen A antibodies on immobilized porcine pepsinogen A did not result in an enrichment of anti-pepsinogen A antibodies.

Stress-related mucosal disease in the critically ill patient

Bleeding from stress-related mucosal disease in critically ill patients remains an important clinical management issue. Although only a small proportion (1-6%) of patients admitted to an intensive care unit (ICU) will bleed, a substantial proportion exhibit clinical risk factors (mechanical ventilation for >48 h and a coagulopathy) that predict an increased risk of bleeding. Furthermore, upper gastrointestinal mucosal lesions can be found in 75-100% of patients in ICUs. Although uncommon, stress-ulcer bleeding is a severe complication with an estimated mortality of 40-50%, mostly from decompensating an underlying condition or multiorgan failure. Although the vast majority of patients in ICUs receive stress-ulcer prophylaxis, largely with PPIs, some controversy surrounds their efficacy and safety. Indeed, no single trial has shown that stress-ulcer prophylaxis reduces mortality. Some reports suggest that the use of PPIs increases the risk of nosocomial infections. However, several meta-analyses and cost-effectiveness studies suggest PPIs to be more clinically effective and cost-effective than histamine-2 receptor antagonists, without considerable increases in nosocomial pneumonia. To help clinicians use the most appropriate strategy for treatment of patients in the ICU, this Review presents the latest information on all aspects of stress-related mucosal disease.

[Mechanisms and risk factors for type 1 food allergies: the role of gastric digestion]

True food allergens are considered as digestion stable proteins, which are absorbed through the gastrointestinal epithelium in an intact form leading to sensitization and causing systemic symptoms. According to classifications, allergens, which are digestion-labile, cause local symptoms by their cross-reactivity towards inhalative allergens. Our recent studies revealed that digestion labile allergens can also have sensitizing capacity if gastric digestion is hindered. The increase of gastric pH via acid-suppression by proton pump inhibitors, sucralfate or antacids, interferes with protein digestion, and leads to sensitization and allergic reaction in mouse models as well as in human patients. Furthermore, the inhibition of digestion increases the risk for anaphylactic responses in sensitized individuals.Even though also other factors, such as sphingolipid metabolites, are associated with the development of food allergies, it is without any doubt that the stomach has an important gate keeping function against food allergies.

Anti-acid medication as a risk factor for food allergy

An important feature for oral allergens is their digestion-resistance during gastrointestinal transit. For some oral allergens, digestion stability is an innate feature, whereas digestion-labile antigens may only persist in times of impairment of the digestive system. In this review, we collect evidence from mouse and human studies that besides the inherent molecular characteristics of a food protein, the stomach function is decisive for the allergenic potential. Gastric acid levels determine the activation of gastric pepsin and also the release of pancreatic enzymes. When anti-ulcer drugs inhibit or neutralize gastric acid, they allow persistence of intact food allergens and protein-bound oral drugs with enhanced capacity to sensitize and elicit allergic reactions via the oral route. Mouse studies further suggest that maternal food allergy arising from co-application of a food protein with anti-acid drugs results in a Th2-biased immune response in the offspring. Especially, anti-ulcer drugs containing aluminum compounds act as Th2 adjuvants. Proton pump inhibitors act on proton secretion but also on expression of the morphogen Sonic hedgehog, which has been related to the development of atrophic gastritis. On the other hand, atrophic gastritis and resulting hypoacidity have previously been correlated with enhanced sensitization risk to food allergens in elderly patients. In summary, impairment of gastric function is a documented risk factor for sensitization against oral proteins and drugs.

Progastriscin: structure, function, and its role in tumor progression

Progastricsin (PGC) is a major seminal plasma protein having aspartyl proteinases-like activity and showing close sequence similarity to pepsins. PGC is also present as zymogen in gastric mucosa. In this article, we have reviewed all important features of PGC. Furthermore, we have compared all features of PGC with those of different aspartyl proteinases. The complete amino acid sequence of PGC reveals that it is composed of 374 residues (gastricsin moiety of 331 residues and the activation segment of 43 residues). The gene of human PGC is located at single locus on chromosome 6, whereas the human pepsinogen genetic locus is polymorphic and codes for at least three distinct polypeptide sequences on chromosome 11. The major useful function of PGC includes production of pro-antimicrobial substance in seminal plasma. The crystal structure of human PGC is known, which shows that it is quite similar to that of porcine pepsinogen. The tertiary structure of PGC is comprised of commonly bilobal structure with a large active-site cleft between the lobes. Two aspartate residues in the center of the cleft, namely Asp32 and Asp215, function as catalytic residues. The sequence and structural features of PGC indicate that it is diverged from its pepsinogen ancestor in the early phase of the evolution of gastric aspartyl proteinases. Our detailed review of PGC structure, function and activation mechanism will also be of interest to cancer biologists as well as gastroenterologists.

The role of protein digestibility and antacids on food allergy outcomes

Digestion assays with simulated gastric fluid have been introduced for characterization of food proteins to imitate the effect of stomach proteolysis on dietary compounds in vitro. By using these tests, dietary proteins can be categorized as digestion-resistant class 1 (true allergens triggering direct oral sensitization) or as labile class 2 allergens (nonsensitizing elicitors). Thus the results of these digestion assays mirror situations of intact gastric proteolysis. Alterations in the gastric milieu are frequently experienced during a lifetime either physiologically in the very young and the elderly or as a result of gastrointestinal pathologies. Additionally, acid-suppression medications are frequently used for treatment of dyspeptic disorders. By increasing the gastric pH, they interfere substantially with the digestive function of the stomach, leading to persistence of labile food protein during gastric transit. Indeed, both murine and human studies reveal that antiulcer medication increases the risk of food allergy induction. Gastric digestion substantially decreases the potential of food proteins to bind IgE, which increases the threshold dose of allergens required to elicit symptoms in patients with food allergy. Thus antiulcer agents impeding gastric protein digestion have a major effect on the sensitization and effector phase of food allergy.

Interaction of pepsin with aromatic amino acids and their derivatives immobilized to Sepharose

The interaction of porcine pepsin A with immobilized derivatives of aromatic amino acids was investigated. Divinyl sulfone-activated Sepharose was used to immobilize N-acetyl-l-phenylalanine and 3,5-diiodo-l-tyrosine via their free carboxyl groups and l-tyrosine via its amino group. Immobilized l-tyrosine was iodinated after coupling. The optimum conditions for the separation of porcine pepsin A using the prepared affinity carriers were studied and the following parameters were established: enzyme recovery, reproducibility of analyses, capacity and dependence of the elution peak area on the concentration of the loaded enzyme. The ability of the prepared affinity carriers to retain various types of proteins was compared under optimum conditions for porcine pepsin A separation. While immobilized 3,5-diiodo-l-tyrosine and iodinated l-tyrosine-Sepharose adsorbed relatively high amounts of bovine serum albumin and ovalbumin, only negligible amounts of these proteins were adsorbed to immobilized N-acetyl-l-phenylalanine. The behavior of porcine pepsin A was the same as its complex with pepstatin A on the prepared affinity carriers, indicating that the enzyme active site is not involved in the studied interaction.

Investigation of the Mechanisms Underlying the Gastroprotective Effect of Nicorandil

AIM

This study investigated possible mechanisms underlying the gastroprotective effect of nicorandil on experimentally-induced gastric lesions in rats.

METHODS

Rats were randomly assigned to vehicle-, nicorandil (10 mg/kg)-, glibenclamide (6 mg/kg)-, nicorandil + glibenclamide- and cimetidine-pretreated groups, in addition to non-stressed control group, to demonstrate whether the K(ATP )channel opening contributed to nicorandil's gastroprotection. Lesions were induced by water immersion-restraint stress (WIRS) and ulcer indices were determined. Gastric juice parameters (pH, acid output, pepsin and mucin concentrations) were determined. Another set of rats was divided into control, saline-pretreated and nicorandil (10 mg/kg)-pretreated groups. Rats underwent WIRS and their stomachs were used for determination of gastric mucosal lipid peroxides, histamine, PGE(2), and total nitrites levels.

RESULTS

Nicorandil displayed significant protection against gastric lesions formation, abolished by concomitant administration of glibenclamide. Nicorandil significantly reduced gastric acid and pepsin secretion, but upon coadministration with glibenclamide, these effects were blocked. Additionally, nicorandil significantly reduced gastric mucosal lipid peroxides and total nitrites, but did not affect PGE(2) and histamine levels.

CONCLUSION

Results confirm a gastroprotective effect for nicorandil, the mechanism of which comprises K(ATP) channel opening, free radical scavenging, decrease of pepsin and acid secretion and prevention of the detrimental rise in nitric oxide during WIRS.

Affinity chromatography of porcine pepsin A using quinolin-8-ol as ligand

Stationary phase containing quinolin-8-ol immobilized on macroporous methacrylate support for the affinity chromatography of porcine pepsin A is described. Optimized chromatographic conditions for separation of porcine pepsin A on this stationary phase were found investigating the influence of pH, concentration, ionic strength and chemical composition of the used mobile phases. The stationary phase shows a good reproducibility of chromatographic analyses (relative standard deviation, +/-2%), a high recovery (ca. 93%) and a satisfactory capacity (13 mg pepsin A/1 mL stationary phase) for porcine pepsin A. The obtained findings confirm the applicability of affinity chromatography on the stationary phase with immobilized quinolin-8-ol to the isolation and determination of porcine pepsin A.

Gastroduodenal mucus bicarbonate barrier: protection against acid and pepsin

Secretion of bicarbonate into the adherent layer of mucus gel creates a pH gradient with a near-neutral pH at the epithelial surfaces in stomach and duodenum, providing the first line of mucosal protection against luminal acid. The continuous adherent mucus layer is also a barrier to luminal pepsin, thereby protecting the underlying mucosa from proteolytic digestion. In this article we review the present state of the gastroduodenal mucus bicarbonate barrier two decades after the first supporting experimental evidence appeared. The primary function of the adherent mucus gel layer is a structural one to create a stable, unstirred layer to support surface neutralization of acid and act as a protective physical barrier against luminal pepsin. Therefore, the emphasis on mucus in this review is on the form and role of the adherent mucus gel layer. The primary function of the mucosal bicarbonate secretion is to neutralize acid diffusing into the mucus gel layer and to be quantitatively sufficient to maintain a near-neutral pH at the mucus-mucosal surface interface. The emphasis on mucosal bicarbonate in this review is on the mechanisms and control of its secretion and the establishment of a surface pH gradient. Evidence suggests that under normal physiological conditions, the mucus bicarbonate barrier is sufficient for protection of the gastric mucosa against acid and pepsin and is even more so for the duodenum.

Anti‐ulcer drugs promote IgE formation toward dietary antigens in adult patients

Recently, we have demonstrated that anti-ulcer drugs, such as H2-receptor blockers and proton pump inhibitors, promote the development of immediate type food allergy toward digestion-labile proteins in mice. The aim of this study was to examine the allergological relevance of these findings in humans. In an observational cohort study, we screened 152 adult patients from a gastroenterological outpatient clinic with negative case histories for atopy or allergy, who were medicated with H2-receptor blockers or proton pump inhibitors for 3 months. IgE reactivities to food allergens before and after 3 months of anti-acid treatment were compared serologically. Ten percent of the patients showed a boost of preexisting IgE antibodies and 15% de novo IgE formation toward numerous digestion-labile dietary compounds, like milk, potato, celery, carrots, apple, orange, wheat, and rye flour. Thus, the relative risk to develop food-specific IgE after anti-acid therapy was 10.5 (95% confidence interval: 1.44-76.48). The long-term effect was evaluated 5 months after therapy. Food-specific IgE could still be measured in 6% of the patients, as well as significantly elevated serum concentrations of ST2, a Th2-specific marker. An unspecific boost during the pollen season could be excluded, as 50 untreated control patients revealed no changes in their IgE pattern. In line with our previous animal experiments, our data strongly suggest that anti-ulcer treatment primes the development of IgE toward dietary compounds in long-term acid-suppressed patients.

Affinity chromatography of porcine pepsin and pepsinogen using immobilized ligands derived from the specific substrate for this enzyme

Affinity chromatography of porcine protease and its zymogen was carried out on immobilized components of specific substrate used for the pepsin determination. For the immobilization of N-acetyl-L-phenylalanine and iodinated derivative of L-tyrosine, divinyl sulfone activated Sepharose was used. Ligands with blocked amino group and free carboxyl one were linked to Sepharose via ethylene diamine spacer using carbodiimide reaction. Conditions of affinity chromatography of porcine pepsin and pepsinogen on the prepared carriers were optimized: the effect of pH, ionic strength and a nature of the buffers used on adsorption of the enzyme and zymogen to an affinity carrier, as well as their elution was studied. The following parameters were taken into consideration: capacity of the prepared affinity matrices, reproducibility of experiments and the enzyme stability. Pepsin was adsorbed to both immobilized ligands at pH 3.5-4.0; for the elution of the enzyme it was necessary to increase ionic strength (up to 0.5 M). For the adsorption of pepsinogen pH 5.2 was found to be optimum, for its desorption, an increase of ionic strength was used.

Stress-related mucosal disease in critically ill patients

Stress-related mucosal disease is common in critically ill patients and can result in significant morbidity. The pathophysiology of this condition is multifactorial but mucosal ischaemia and gastric acid have pivotal roles. The major risk factors for developing stress-related mucosal bleeding are prolonged mechanical ventilation and coagulopathy. The mainstay of clinical management is prevention with acid-suppressing medications and cytoprotective agents. This chapter discusses medications used to prevent this condition and suggests an approach for management. Recent developments in gastroenterology include the development and use of proton pump inhibitors and the discovery of the association Helicobacter pylori with gastritis. The role of each of these in stress-related mucosal disease is discussed. Finally, an approach to the bleeding critically ill patient is presented.

Expression and clinical significance of pepsinogen C in epithelial ovarian carcinomas

BACKGROUND

Pepsinogen C (pep C) is a gastric aspartic protease of which is associated with a favorable prognosis in breast cancer. Recently, it has been demonstrated in other tumors of extradigestive origin.

STUDY DESIGN

We have analyzed pep C expression in 72 epithelial ovarian carcinomas by immunohistochemistry.

RESULTS

Nineteen (26%) tumors stained positively for pep C. Overall this expression was not associated with the clinicopathologic characteristics or with outcome. However, in patients with serum levels of CA 125 less than 35 U/ml, pep C expression identified a group with a more favorable prognosis.

CONCLUSION

Pepsinogen C is expressed in a quarter of ovarian carcinomas and might identify a subset of patients with different prognosis.

The potential risk factors leading to peptic ulcer formation in autoimmune disease patients receiving corticosteroid treatment

AIM

To study the potential risk factors leading to peptic ulcer disease among autoimmune disease patients on corticosteroid treatment.

METHODS

One hundred and thirty-eight corticosteroid-treated autoimmune disease patients were enrolled; their demographic data were recorded and laboratory data were measured. Endoscopy was performed to assess the occurrence of peptic ulcer disease. Helicobacter pylori infection was diagnosed on the basis of rapid urease test and histological examination.

RESULTS

Twenty-eight (20%) of 138 autoimmune disease patients had peptic ulcer disease, including 17 with gastric ulcer, eight with duodenal ulcer and three with gastric ulcer plus duodenal ulcer. Eighty five (62%) had used non-steroidal anti-inflammatory drugs and 46 (33%) had H. pylori infection. The majority of peptic ulcer disease subjects showed the following characteristics: age >or= 60 years; male; smokers; non-steroidal anti-inflammatory drug users, particularly the non-specific cyclo-oxygenase inhibitors; presence of hyperpepsinogenaemia I; low H. pylori colonization (P < 0.05). Multivariate analysis revealed that an age >or= 60 years [odds ratio (OR), 6.80; P = 0.001], smoking (OR, 7.94; P = 0.004) and the use of non-specific cyclo-oxygenase inhibitors (OR, 4.71; P = 0.030) were the predominant risk factors for the development of peptic ulcer disease among these patients, whereas H. pylori infection showed a protective role (OR, 0.20; P = 0.022).

CONCLUSIONS

Old age, smoking and the use of non-specific cyclo-oxygenase inhibitors are risk factors for peptic ulcer disease in autoimmune disease patients on corticosteroid treatment. H. pylori infection appears to protect against peptic ulcer disease in these patients.

Aromatic amino acids and their derivatives as ligands for the isolation of aspartic proteinases

Affinity chromatography was used to study an interaction of aspartic proteinases with immobilized aromatic amino acids and their derivatives. The following ligands were used: L-tyrosine, 3-iodo-L-tyrosine, 3,5-diiodo-L-tyrosine, L-phenylalanine, p-iodo-L-phenylalanine and N-acetyl-L-phenylalanine. With the exception of the last one, ligands were coupled directly to divinyl sulfone activated Sepharose 4B. For the preparation of immobilized N-acetyl-L-phenylalanine, divinyl sulfone activated Sepharose 4-B with linked ethylene diamine was used. Porcine pepsin was used for the evaluation of the capacity of the prepared affinity carriers. The capacity of the immobilized amino acid derivatives significantly increased in comparison with the non-derivatized amino acids. The prepared immobilized ligands were further used for the separation of human pepsinogens.

Regulation of human and mouse procathepsin E gene expression

Cathepsin E is an intracellular aspartic proteinase that is considered to have a number of physiological roles including antigen processing. Quantitation of procathepsin E mRNA by LightCyclertrade mark technology indicated that the gene was transcribed in lung but not in kidney of both human and mouse origin. In contrast, the transcript was present in mouse spleen and alveolar macrophages but not in the counterpart tissue/cells from humans. Regulation of human and mouse procathepsin E gene expression was shown not to be influenced by the extent of CpG methylation but depended on the recognition of potential binding motifs in each promoter region by transcription factors such as GATA1, PU1 and YY1, as revealed by functional analysis using a series of promoter/luciferase reporter gene fusion constructs. Thus the extent to which the procathepsin E gene is expressed in a particular cell type may depend on the balance between the effects produced by positive-acting, cell-specific transcription factors such as GATA1 and PU1 and the negative influence of the ubiquitous YY1 factor. In this way, the relative abundance and influence of general and cell-specific transcription factors can govern the production of cathepsin E and thereby account for the sporadic cell and tissue distribution of this enzyme in different species.

Pepsin-mediated processing of the cytoplasmic histone H2A to strong antimicrobial peptide buforin I

The intestinal epithelium forms a first line of innate host defense by secretion of proteins with antimicrobial activity against microbial infection. Despite the extensive studies on the antimicrobial host defense in many gastrointestinal tracts, little is known about the antimicrobial defense system of the stomach. The potent antimicrobial peptide buforin I, consisting of 39 aa, was isolated recently from the stomach tissue of an Asian toad, Bufo bufo gargarizans. In this study we examined the mechanism of buforin I production in toad stomach tissue. Buforin I is produced by the action of pepsin isozymes, named pepsin Ca and Cb, cleaving the Tyr39-Ala40 bond of histone H2A. Immunohistochemical analysis revealed that buforin I is present extracellularly on the mucosal surface, and unacetylated histone H2A, a precursor of buforin I, is localized in the cytoplasm of gastric gland cells. Furthermore, Western blot analysis showed that buforin I is also present in the gastric fluids, and immunoelectron microscopy detected localization of the unacetylated histone H2A in the cytoplasmic granules of gastric gland cells. The distinct subcellular distribution of the unacetylated histone H2A and the detection of the unacetylated buforin I both on the mucosal surface and in the lumen suggest that buforin I is produced from the cytoplasmic unacetylated histone H2A secreted into the gastric lumen and subsequently processed by pepsins. Our results indicate that buforin I along with pepsins in the vertebrate stomach may contribute to the innate host defense of the stomach against invading microorganisms.

Electrotitration curves of human gastric pepsinogens in agarose gels

Electrotitration curves (ETC) of a marker protein mixture, pH 2.5-5.65, and human pepsinogens were performed in an agarose gel, containing 2% acid carrier ampholytes, forming a pH range of 2.5-5. Although the establishment of the pH gradient by isoelectric focusing was not quite complete and linear, both biochemically and immunochemically different types of pepsinogen C (PGC) and pepsinogen A (PGA) zymogens as well as the acid isoelectric points (pI) marker proteins were separated with good resolution. Three main fractions of PGA (Pg3, Pg4, and Pg5) were detected. To obtain an exact determination of the pepsinogen pIs, a simple and very fast 10 s pressure blot technique was applied. Human pepsinogens were separated alone or mixed with pI marker proteins in the pH range 2.4-5.65. No effect of the markers was observed on the pepsinogen migration. To visualize the different protein samples in the gel and on nitrocellulose membrane, we have used colloidal gold (AuroDye) staining, proteolytic activity, and immunostaining with monoclonal antibodies anti PGA and PGC. The described method shows an ability to separate proteins at acidic conditions with a resolution comparable to isoelectric focusing with immobilized pH gradients, but much faster, easier, and cheaper. In addition, the technique allows us to determine precise and exact pI values, and is suitable for studies of the pepsinogen polymorphism and its role in gastric diseases.

Pepsinogens: physiology, pharmacology pathophysiology and exercise

Human gastric mucosa contains aspartic proteinases that can be separated electrophoretically on the basis of their physical properties into two major groups: Pepsinogen I (PGA, PGI); and Pepsinogen II (PGC, PGII). Pepsinogens consist of a single polypeptide chain with molecular weight of approximately 42,000 Da. Pepsinogens are mainly synthesized and secreted by the gastric chief cells of the human stomach before being converted into the proteolytic enzyme pepsin, which is crucial for the digestive processes in the stomach. Pepsinogen synthesis and secretion are regulated by positive and negative feed-back mechanisms. In the resting state pepsinogens are stored in granules, which inhibit further synthesis. After appropriate physiological or external chemical stimuli, pepsinogens are secreted in the stomach lumen where hydrochloric acid, secreted by the parietal cells, converts them into the corresponding active enzyme pepsins. The stimulus-secreting coupling mechanisms of pepsinogens appear to include at least two major pathways: one involving cAMP as a mediator, the other involving modification of intracellular Ca(2+)concentration. Physiological or external chemical stimuli acting through the intracellular metabolic adenyl cyclase are more effective in inducing ' de novo ' pepsinogen synthesis than those acting through intracellular Ca(2+). The activation of protein kinase C (PK-C) would appear to be involved in regulatory processes. The measurement of pepsinogens A and C in the serum is considered to be one of the non-invasive biochemical markers for monitoring peptic secretion and obtaining information on the gastric mucosa status of healthy subjects. Recently, pepsinogen measurements have been used as an effective biochemical method for evaluating and monitoring patients with gastrointestinal diseases and for checking the effects of drug treatment. The level of PGA in the serum is always high in normal gastritis, while in atrophic gastritis it is always low. In both cases the PGC level in the serum is high. In most gastrointestinal pathologies the ratio between the PGA/PGC decreases. Various reports concerning hormone and/or enzyme modification as well as gastrointestinal distress in the case of long distance exercise have been reported. It has been suggested that the origin of the gastrointestinal distress experienced by long distance runners is a transient ischaemia of the gastric mucosa; it is also suggested that a hypobaric-hypoxic environment could contribute to induce gastric mucosa necrosis. Interrelation between gastrointestinal distress, hypobaric-hypoxic environment and modifications of PGA and PGC, gastrin and cortisol was evaluated in 13 athletes after a marathon performed at 4300 m. Gastrointestinal symptoms occurred in approximately 40% of the athletes. After the race the athletes showed a significant increase of gastrin and cortisol, while the ratio between PGA/PGC decreased. No relationship was observed between gastrointestinal symptoms and hormonal changes after the race. A control group of five subjects, who had been exposed to the same environmental conditions, showed no gastrointestinal or hormonal alteration. Conversely, control subjects presented a significant decrease of cortisol related to the circadian rhythm. The same incidence of gastrointestinal symptoms at high altitude and at sea level and the absence of pathological alteration of PGA and PGC in the serum of the athletes indicates that running a marathon and living for 6 days at 4300 m does not induce gastric mucosa necrosis. Cortisol and gastrin alteration observed in the athletes at this altitude would seem to be related to an activation of the mesopontine and forebrain structures involved in the behavioural and metabolic integration of the autonomic control and arousal and psychophysical-exercise stress. 2000 Academic Press@p$hr

Binding of pepsinogen to the 78 kDa gastrin binding protein

An endogenous ligand of the 78 kDa gastrin-binding protein (GBP) has been purified from detergent extracts of porcine gastric mucosal membranes by ion exchange chromatography and preparative gel electrophoresis. The ligand bound to the GBP with high affinity (mean IC50 value of 0.31+/-0.09 microgram/ml, or 8 nM), as assessed by inhibition of cross-linking of iodinated gastrin2,17 to the GBP. Both the N- and C-terminal halves of the GBP, which had been expressed individually as glutathione-S-transferase fusion proteins in Escherichia coli, and purified on glutathione-agarose beads, bound the ligand. Two peptides derived from the ligand were purified by reversed-phase high-performance liquid chromatography (HPLC), and characterised by mass spectrometry and Edman sequencing. The peptides were 97% and 100% identical, respectively, to amino acids 119-157 and 199-219 of porcine pepsinogen A. Commercial samples of pepsinogen also bound to the GBP, with a mean IC50 value of 3.9+/-1. 2 micrograms/ml (100 nM). We conclude that the ligand is closely related, but not identical, to pepsinogen A.

The long-lasting effect of TU-199, a novel H+, K(+)-ATPase inhibitor, on gastric acid secretion in dogs

We have used Heidenhain-pouch dogs to investigate the effects of (+/-)-5-methoxy-2-{[(4-methoxy-3,5-dimethylpyrid-2-yl)methyl]sulph inyl}-1H-imidazo[4,5-b]pyridine (TU-199), an imidazopyridine derivative, on gastric acid secretion stimulated by histamine, carbachol and tetragastrin. We have also investigated the duration of the antisecretory effect of TU-199 using a measurement of intragastric pH for 24 h in gastric fistula dogs whose gastric acid secretion was stimulated by histamine. Single oral administration of TU-199 (0.1, 0.2 and 0.4mgkg(-1)) dose-dependently suppressed gastric acid secretion stimulated by histamine infusion. Oral treatment with TU-199 (0.2, 0.4 and 0.8 mg kg(-1)) also dose-dependently inhibited acid secretion induced by carbachol and tetragastrin. The inhibitory effect of TU-199 on stimulated gastric acid secretion was more potent than that of omeprazole, a well-known H+,K(+)-ATPase inhibitor in dogs. Repeated oral treatment with TU-199 at a dose of 0.2 mg kg(-1) once a day for seven days markedly suppressed histamine-stimulated gastric acid secretion in dogs. This inhibitory effect of TU-199 reached a maximum level after three or four doses and was more pronounced than that of omeprazole or lansoprazole. In gastric fistula dogs, the duration of intragastric pH-elevation by administration of TU-199 (0.3 mg kg(-1)) was much longer than that of omeprazole (0.6mgkg(-1)) or lansoprazole (0.9mgkg(-1)). The IC50 values (doses resulting in 50% inhibition) of TU-199, omeprazole and lansoprazole with regard to H+,K(+)-ATPase activity in dog gastric mucosal microsomes were 8.6, 8.8 and 9.9 microM, respectively. These results indicate that TU-199 inhibits gastric acid secretion via suppression of a H+,K(+)-ATPase activity. Our findings also suggest that TU-199 might have potent and long-lasting effects on gastric acid secretion.

Stimulation of pepsinogen release from chief cells by Helicobacter pylori: evidence for a role of calcium and calmodulin

To define the mechanisms by which Helicobacter pylori stimulates pepsinogen secretion, the in vitro release of pepsinogen was studied using a preparation of pig chief cell monolayers. Helicobacter pylori induced a time- and concentration-dependent release of pepsinogen into the medium, with about a three-fold increase in pepsinogen secretion over controls found after 45 min of incubation. 3x10(7) H. pylori produced 50% of the maximal response found at a H. pylori count of 2x10(8). The action of H. pylori did not depend on the presence of the vacuolating toxin (vacA) and the cytotoxin-associated protein (cagA). Dibutyryl-cAMP and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate also markedly stimulated pepsinogen secretion and enhanced the stimulatory effect of H. pylori. Helicobacter pylori-stimulated pepsinogen release was inhibited by lanthanum and the calmodulin antagonist W-7, but not by the L-type Ca2+ channel blocker nifedipine, TMB-8, an agent that blocks the release of Ca2+ from intracellular stores, the protein kinase C inhibitor staurosporine and the protein kinase A inhibitor H-8. It is suggested that H. pylori directly stimulates pepsinogen release from gastric chief cells and that this effect is mediated via the calcium/calmodulin messenger branch.

Rhythmic patterns in incidence of peptic ulcer perforation over 5.5 decades in Norway

The incidence of ulcer perforation in 1480 patients treated in the Bergen area of Norway between 1935 and 1990 was analyzed for daily (circadian), weekly (circaseptan), and yearly (circannual) time effects. A circadian rhythm was found overall that was reproducible and fairly stable across seasons, decades, and days of the week. After subgrouping, a circadian rhythm was found in younger patients, males, and duodenal perforations, while a 12 h (circasemidian) rhythm characterized ulcer perforation for women and for gastric ulcers. Duodenal perforations showed highest incidence in the afternoon, while gastric perforations showed a major peak around noon and a secondary peak near midnight. For duodenal ulcer perforation, the circannual pattern was characterized by a 6-month rhythm, with significantly higher incidence in May-June-July and in November-December in most subgroups. A circaseptan rhythm was not found, but there was a significantly higher incidence on Thursday-Friday as compared to Sunday-Monday. The pathophysiological mechanisms underlying the perforation of an ulcer thus seemed to show pronounced circadian and 6-month rhythmic variations, much less so circaseptan or circannual rhythms. While it is likely that exogenous environmental and/or societal factors play a significant role, variations in ulcer perforation may be related to endogenous biological rhythms in pathophysiological factors since the circadian pattern of duodenal perforation follows that for gastric acidity. Knowledge of the temporal patterns in peptic ulcer perforation and associated pathophysiologic factors should prove useful in optimizing the chronotherapeutic management of ulcer disease.

Pepsinogen C gene product is a possible growth factor during gastric mucosal healing

We isolated, by the subtraction cloning method, a pepsinogen C (PGC) gene fragment (the sequence between the 968th and 1179th base pairs) from a rat gastric mucosal cDNA library as a cDNA clone encoding a substance that promotes growth of the normal rat gastric mucosal cell line RGM1. Northern blot analysis revealed that PGC gene expression was enhanced not only in acetic acid-induced chronic gastric ulcers but also in indomethacin-induced gastric mucosal lesions. PGC gene expression was also increased in the Helicobacter felis-infected stomachs. Thus, the PGC gene may play a role in gastric epithelial cell growth during gastric mucosal healing.

Gastric secretion in Chinese patients with cirrhosis

The role of gastric secretion has been controversial in patients with cirrhosis. Except for studies of gastric secretion in cirrhotic patients who underwent a shunt operation, there is no report correlating gastric secretion with portal pressure in patients with cirrhosis. In this study, we evaluated gastric secretion in cirrhotic patients and correlated it with hemodynamic parameters. Within 12 months, 20 normal volunteers and 16 cirrhotic patients were enrolled. Gastric secretion was assessed in all patients, but portal pressure hemodynamic studies were performed only in cirrhotic patients. We found that the median basal acid output, maximal acid output, and basal pepsin output in the controls (1.41 mmol/h, 9.2 mmol/h, and 0.02 mg/h, respectively) and in the cirrhotic patients (0.6 mmol/h, 7.84 mmol/h, and 1.5 mg/h, respectively) were not statistically different. However, maximal pepsin output was lower in the cirrhotic patients (1.5 mg/h) than in the normal subjects (5.14 mg/h) (p < 0.05). Gastric secretion correlated poorly with hepatic venous pressure gradient (HVPG) and the presence of congestive gastropathy in cirrhotic patients. The severity of congestive gastropathy correlated poorly with HVPG. Helicobacter pylori has difficulty replicating in the stomach when HVPG is > 14 mm Hg. We conclude that patients with cirrhosis have a lower maximal pepsin output than that of the healthy subjects. Gastric secretion correlates poorly with HVPG and the presence of congestive gastropathy in patients with cirrhosis.

Detection of pathological changes of proteins by peptide mapping after protein digestion by use of oriented immobilized proteinases

Diagnostic methods for detecting gastric diseases using chymotryptic digestion of pepsin are discussed. Peptide maps can be prepared using reversed-phase high-performance liquid chromatography. Batchwise chromatography by use of membranes with immobilized Tyr(I2) was used for the isolation of pepsin from gastric mucosa extract or from human blood serum. Enzymes immobilized using suitable antibodies or through their sugar moieties can be used for the preparation of peptide maps because such enzymes share good steric accessibility to their active binding sites and possess increased thermal stability. Biospecific adsorption of proteins to immunosorbents combines the simultaneous isolation of these enzymes with their oriented immobilization. Proteins were stabilized by hydrophilization through the attachment of saccharide residues containing galactose residues. These residues could be activated by oxidation using galactose oxidase and subsequently immobilized to hydrazide-containing solid supports.

Role of cysteine proteases and protease inhibitors in gastric mucosal damage induced by ethanol or ammonia in the rat

Since recent studies suggest an imbalance between cathepsin B and its tissue protease inhibitors (PI) in the pathogenesis of acute and chronic diseases, we tested the hypothesis that release of activated cysteine proteases (P) such as cathepsins B, H, and L might play a role in the pathogenesis of gastric hemorrhagic mucosal lesions (HML) induced by ethanol (E) or ammonia (A). Anesthetized rats received 1 ml of 50% E or 1% A solution intragastrically for 1 min during in situ gastric luminal perfusion. Rapid activation and release of cathepsins B, L, and H into the luminal perfusate preceded the formation of HML quantified by planimetry. Mucosal presence and activity of cysteine PI and cathepsin B have also been investigated in the pathogenesis of chemically induced HML. We extracted and partially isolated acid and thermostable inhibitors of cathepsin B in the gastric mucosa, and found rapid inactivation of PI and activation of cathepsin B in the early phase of E- or A-induced HML. Negative correlations were found between P and PI activities by E or A solutions. Both the activation of cathepsins B, L, and H and the development of E-induced HML were prevented by pretreatment with the sulfhydryl alkylator N-ethylmaleimide. These results suggest that cysteine P may be activated in the rat stomach after E or A exposure, and cysteine P may have a role in the pathogenesis of E- or A-induced gastric HML. Endogenous PI may also participate in the mechanisms of gastric mucosal lesions and gastroprotection.

Hormonal regulation of the human pepsinogen C gene in breast cancer cells. Identification of a cis-acting element mediating its induction by androgens, glucocorticoids, and progesterone

Pepsinogen C is an aspartic proteinase mainly involved in the digestion of proteins in the stomach, which is also synthesized by certain human breast tumors. To examine the possibility that extragastric production of this proteolytic enzyme could be mediated by hormonal factors, we have analyzed pepsinogen C gene expression in human breast cancer cells subjected to different hormonal treatments. Northern blot analyses revealed the expression of pepsinogen C gene by T-47D breast cancer cells after induction with dihydrotestosterone, dexamethasone, and progesterone but not with estradiol, retinoic acid, or ethanol. Reverse transcription-polymerase chain reaction analysis in a series of breast cancer cell lines confirmed the amplification of pepsinogen C mRNA after induction with dihydrotestosterone, in those cells expressing the androgen receptor mRNA. The promoter region of the pepsinogen C gene was functionally characterized by transient expression of a vector containing the promoter region cloned in front of the chloramphenicol acetyltransferase (CAT) reporter gene. CAT activity in T-47D cells was stimulated in the presence of dihydrotestosterone, dexamethasone, and progesterone but not by estradiol. By further deletion mapping of the pepsinogen C promoter, a minimal region (AGAACTattTGTTCC) was identified as being responsible for glucocorticoid-, androgen-, and progesterone-regulated gene expression.

Helicobacter pylori gastritis and serum pepsinogen levels in a healthy population: development of a biomarker strategy for gastric atrophy in high risk groups

This study aimed to estimate the prevalence and type of chronic gastritis in an asymptomatic working population and to determine whether a combination of serum pepsinogen levels and Helicobacter pylori serology could be used to identify a subgroup with atrophic gastritis at elevated risk of gastric carcinoma. A 10% subsample of 544 male volunteer factory workers aged 18-63 years and participating in a larger study underwent endoscopy and biopsy. Of these men, 29 were seropositive for Helicobacter pylori; all but three (89.7%) had chronic gastritis. Serum pepsinogen A levels increased with progression from a corpus predominant pattern of gastritis through pangastritis to an antral predominant pattern. Nine subjects had corpus atrophy, which was in most cases accompanied by fasting hypochlorhydria and hypergastrinaemia. A combination of pepsinogen A below 80 ng ml-1 and Helicobaceter pylori seropositivity detected corpus atrophy with sensitivity 88.9% and specificity 92.3%. A second screening stage, using a pepsinogen A/C ratio of below 2.5 as a cut-off, resulted in a reduction in numbers requiring further investigation but with some loss of sensitivity (77.8%). Application of this two-stage screening programme to the original sample of 544 workers would have resulted in 11 (2.2%) men being selected for follow-up, excluding 25 (5.1%) false negatives. Our results suggest that a combination of serum pepsinogen levels and Helicobacter pylori serology could be useful as a biomarker strategy for detection of individuals at increased risk of gastric carcinoma and for non-invasive investigation of the natural history of Helicobacter pylori gastritis.

Isolated guinea pig gastric chief cells express tumour necrosis factor receptors coupled with the sphingomyelin pathway

The tumour necrosis factor alpha (TNF), has been implicated in the pathogenesis of non-steroidal anti-inflammatory drug (NSAID) induced gastropathy and Helicobacter pylori induced gastritis. Both conditions are characterised by high plasma pepsinogen concentrations, which are thought to reflect an increased rate of enzyme release by the pepsinogen secreting (chief) cells. The mechanisms responsible for this cell dysfunction are unknown. This study investigates whether chief cells express TNF receptors and, if so, whether their activation results in cell death. Immunohistochemical studies conducted with monoclonal antibodies (mAbs) directed against two TNF receptor associated proteins of 55 kDa (TNF-R1) and 75 kDa (TNF-R2) showed that TNF binding sites were expressed in approximately 100% gastric chief cells. Western blot analysis of whole chief cell lysates probed with the TNF-R1 and TNF-R2 mAbs gave two distinct bands of 55 and 75 kDa in the immunoprecipitate. Incubating chief cells with TNF caused concentration and time dependent cell death, which was prevented by pretreating the cells with anti-TNF receptor mAbs. Exposing the cells to TNF reduced sphingomyelin content by 25%. Sphingomyelinase (10(-6) to 10(-2) IU/ml) mimicked the effect of TNF in that it provoked a concentration and time dependent reduction in chief cell viability and increased pepsinogen release. In conclusion, gastric chief cells express two TNF receptors partially linked to the sphingomyelin pathway. TNF induced chief cell dysfunction might be responsible for the high plasma pepsinogen concentrations seen in patients with NSAID gastropathy or H pylori induced gastritis.

Pathophysiological effects of long-term acid suppression in man

A critical evaluation has been made of the available evidence in man of the effects of prolonged low acid states on the structure and function of the stomach. Various human models have been examined. 1. Ageing does not affect acid output from the normal male stomach, and there may be an increase in women. With progressive atrophy of the corpus mucosa, which is more frequent and rapid in patients with gastric ulcer, there is an associated loss of secretory function. Chronic gastritis and atrophy are the most important age-related changes, which in many cultures are hypothesized to develop via a prior Helicobacter pylori-related gastritis. However, H. pylori colonization of the mucosa decreases with increasing grades of gastric atrophy probably because intestinal metaplasia provides a hostile environment. Atrophy and intestinal metaplasia are associated with precancerous lesions and gastric cancer. Apparent hyperplasia of the gastric argyrophil endocrine cells is a common and spontaneous phenomenon in patients with atrophic gastritis, which in part may be related to the preferential loss of nonendocrine cells. 2. Pernicious anemia is associated with a complete lack of acid production, marked hypergastrinemia, and endocrine cell hyperplasia in the majority of patients. ECL-cell carcinoids and gastric cancer occur with a prevalence of 3-7%, and endoscopic surveillance in routine clinical practice is not warranted. 3. Gastric ECL-cell carcinoids are rare events that have been described in association with two diseases in man, pernicious anemia and Zollinger-Ellison syndrome as part of multiple endocrine neoplasia syndrome type I, and usually relate to marked hypergastrinemia and the presence of chronic atrophic gastritis with gastric antibodies or a genetic defect rather than the presence or absence of acid. Regression or disappearance of ECL-cell carcinoids, either spontaneously or after removal of the gastrin drive, has been recorded. Lymph node, and rarely hepatic, metastases are documented but death in these cases has been anecdotal. 4. Therapy with H2 antagonists may result in up to a twofold rise in serum gastrin levels but in man no endocrine cell hyperplasia has been recorded. However, the data for H2 antagonists on these aspects are very limited. There is no drug-related risk of gastric or esophageal cancer, although the incidence of the latter may be raised. Long-term treatment with omeprazole is associated with a two- to fourfold increase in gastrin levels over baseline values in one third of patients and apparent endocrine cell hyperplasia in 7% of cases overall.(ABSTRACT TRUNCATED AT 400 WORDS)

Laboratory medicine in ulcer disease

The role of laboratory medicine in ulcer disease is poorly defined. However there is increasing evidence of the clinical usefulness of some laboratory tests that investigate secretory functions and defensive properties of the stomach, gastrointestinal hormones and Helicobacter pylori infection. These tests may modify the clinical management of patients with peptic ulcer by identifying H. pylori positive subjects, patients with high acid output, patients who do not respond to antisecretory therapy, and patients with high gastrin levels in whom Zollinger-Ellison syndrome may be suspected. Here we review the clinical value of laboratory tests in ulcer disease, particularly as concerns the cost/benefit ratio. The relative merits of these tests are described giving an indication of their possible role in the diagnostic algorithm.

Pepsin concentration in gastroduodenal biopsy homogenates in chronic ulcer disease

A modification of Berstad's spectrophotometric method was tested and proved capable of detecting pepsin concentrations in mucosal perendoscopic biopsy homogenates. The relationship between this parameter and pepsin in gastric juice and pepsinogen group I in serum and in biopsy homogenates was analyzed. From the biochemical point of view, the assay was found sufficiently accurate. Mucosal pepsinogen group I, but not mucosal pepsin, concentration was found higher in gastric and duodenal ulcer patients than in controls. Patients with corpus-fundic gastric ulcer showed significantly lower mucosal pepsin and mucosal pepsinogen group (PG) I. Aging and smoking did not influence either parameter but male duodenal ulcer subjects presented higher mucosal pepsinogen group I concentration. The lack of any relationship between serum and mucosal PG I and between pepsin in gastric juice and in mucosa raises a question, at least in methodological terms, about the validity of using serum pepsinogen group I and pepsin as indicators of peptic output.