Idiopathic gastric acid hypersecretion

Many patients with acid-peptic disease have idiopathic gastric acid hypersecretion defined as a basal acid output >10.0 meq/hr; however, a significant proportion have basal acid outputs >15.0 meq/hr, which is within the range found in Zollinger-Ellison syndrome. Although idiopathic gastric acid hypersecretion is more common than Zollinger-Ellison syndrome, it is important that these two disorders be differentiated because of differences in treatment and natural history. In the present study, we compared 124 patients with idiopathic gastric acid hypersecretion and 137 patients with Zollinger-Ellison syndrome. There were no significant differences with regard to age at diagnosis, history of upper gastrointestinal hemorrhage, nausea, vomiting, and family history of duodenal ulcer and other acid-peptic disease. However, significant differences were observed between patients with idiopathic gastric acid hypersecretion and patients with Zollinger-Ellison syndrome with regard to percentage of males: 77% compared to 64% (P=0.008), mean serum gastrin: 60 pg/ml compared to 3679 pg/ml (normal <100 pg/ml) (P<0.001), mean basal acid output: 15.4 meq/hr compared to 47.0 meq/hr (P<0.001), mean age at onset of symptoms: 33 years compared to 41 years (P<0.001), mean duration of symptoms before diagnosis: 11 years compared to five years (P<0.001), percentage with abdominal pain: 67% compared to 82% (P=0.00004), percentage with diarrhea: 12% compared to 75% (P<0.000001), percentage with pyrosis: 58% compared to 40% (P=0.003), percentage with duodenal ulcer: 53% compared to 74% (P<0.000001), and percentage with esophagitis: 31% compared to 42% (P=0.0004). The differences in clinical features could be attributed to difference in mean basal acid output, and/or differences in levels of basal acid output used for diagnosis of idiopathic gastric acid hypersecretion (basal acid output >10.0 meq/hr) and Zollinger-Ellison syndrome (basal acid output >15.0 meq/hr). When 45 patients with idiopathic gastric acid hypersecretion and 39 patients with Zollinger-Ellison syndrome with basal acid outputs 15.1–30.0 meq/hr were compared, the main significant differences were with regard to mean serum gastrin: 69 pg/ml compared to 655 pg/ml (P<0.001), percentage of male gender: 82% compared to 62% (P=0.03), and percentage with diarrhea: 16% compared to 64% (P=0.000005). These results indicate that in general patients with idiopathic gastric acid hypersecretion and patients with Zollinger-Ellison syndrome often have similar clinical features that can be difficult to distinguish. However, the increased frequency of diarrhea and female gender should lead to a strong suspicion of Zollinger-Ellison syndrome, which can be distinguished in almost every case by measurement of serum gastrin.     

Reversible Basal Gastric Hypersecretion with Parathyroid Adenomas and Duodenal Ulcer

Summary: Profound hypersecretion of gastric acid, basally, was detected in a duodenal ulcer patient with familial primary hyperparathyroidism. Repeated fasting serum gastrin estimations were normal. Following surgical treatment of the hyperparathyroidism, there was a sustained fall in basal acid output from 34 to 4.5 mEq per hour. Two years later, an infusion of calcium intravenously re-produced dramatic gastric acid hyper-secretion, up to 64 mEq per hour, confirming the extreme hypersensitivity to mild hypercalcaemia. The infusion also provoked a rise in serum gastrin levels.
This study has demonstrated that pronounced basal acid hypersecretion with ulcer may occur in hyperparathyroidism in the absence of the Zollinger-Ellison syndrome. Thus, parathyroid adenomas do sometimes influence gastric secretion like a gastrin-producing tumour, or a retained excluded gastric antrum. This exaggerated response may be mediated by rises in serum gastrin, stimulated by calcium.     

Definition for idiopathic gastric acid hypersecretion

Zollinger-Ellison syndrome and other gastric acid hypersecretory states in which a specific etiology is identified are defined as a basal acid output of greater than 15.0 meq/hr. To determine the level of basal acid output that defines idiopathic gastric hypersecretion, basal acid outputs were investigated in normal subjects and patients with duodenal ulcers, and functional and statistical definitions for idiopathic gastric acid hypersecretion were developed. Sixty-five normal subjects were evaluated to define idiopathic gastric acid hypersecretion on a statistical basis, and 22 patients with refractory duodenal ulcers were evaluated to define idiopathic gastric acid hypersecretion on a functional basis. Mean basal acid output for the 65 normal subjects was 3.0±2.7 meq/hr. Even though the mean basal acid output for the group of 28 normal male subjects was slightly higher than for the group of 37 normal female subjects, the groups were not significantly different. The 95% confidence interval around the mean basal acid output for all normal subjects was 2.4–3.7 meq/hr, with little difference between the male and female groups. The mean basal acid output plus two standard deviations and the mean basal acid output plus three standard deviations for the 65 normal subjects were 8.4 meq/hr and 11.1 meq/hr, respectively. Of 109 patients with active duodenal ulcers treated for eight weeks with standard doses of antisecretory medication, 22 showed no healing as documented by endoscopy. The mean basal acid output for these 22 patients with nonhealed duodenal ulcers was 18.7 meq/hr (range 10.1–49.1 meq/hr) while mean basal acid output for the 87 patients with healed duodenal ulcers was 7.5 meq/hr (range 0.0–27.9 meq/hr). The difference in mean basal acid output between these two groups was statistically different (P<0.001). All patients with refractory duodenal ulcers had basal acid outputs of greater than 10.0 meq/hr. Our results indicate that the definition for idiopathic gastric acid hypersecretion should be a basal acid output of greater than 10.0 meq/hr, since, based on refractory duodenal ulcer disease, the functional definition for idiopathic gastric acid hypersecretion is a basal acid output of greater than 10.0 meq/hr, which in our data also corresponds well to the statistically defined range of basal acid output in normal subjects.     

Maintenance oral pantoprazole therapy is effective for patients with Zollinger-Ellison syndrome and idiopathic hypersecretion

OBJECTIVE: Maintenance proton pump inhibitor (PPI) therapy is effective for gastric acid hypersecretory states, although data with pantoprazole are limited. The aim of this study was to evaluate the safety and efficacy of long term p.o. pantoprazole in individuals with hypersecretion. METHODS: All subjects had Zollinger-Ellison syndrome or idiopathic hypersecretion. Baseline acid output was measured in the presence of prior maintenance antisecretory therapy before pantoprazole exposure. The starting dose was 40 mg b.i.d. in most cases, and the dose was adjusted to document control within the first 2 wk of therapy. The maximal allowable dose was 240 mg daily. Acid output was measured on day 28 and then quarterly from month 3. The primary efficacy endpoint was documented control of acid secretion at 6 months, i.e., acid output in the last 1 h before the next dose of therapy of <10 mEq/h (<5 mEq/h in subjects with prior acid-reducing surgery). RESULTS: A total of 26 subjects had Zollinger-Ellison syndrome (six with multiple endocrine neoplasia syndrome type 1) and nine had idiopathic hypersecretion. Pre-enrollment therapy included omeprazole in 27 subjects and lansoprazole in eight, and 82.4% of subjects were controlled on their prior regimens. With upward dose titration, acid output was controlled in all subjects by day 10 and in all but two (6%) at the 6-month time point. Median acid secretion on therapy at 6 months was <2 mEq/h (mean 2.2 mEq/h; range 0-10.5 mEq/h) at a dose of 40 mg b.i.d. for 24 subjects, 80 mg b.i.d. for seven subjects, and 120 mg b.i.d. for two subjects. During the course of the study, five subjects required doses of 240 mg daily. Pantoprazole was generally well tolerated. No cases of anterior optic ischemic neuropathy occurred. Five subjects died during follow-up, all because of events unrelated to the study drug. CONCLUSIONS: Maintenance p.o. pantoprazole therapy at a dose of 80-240 mg/day in divided doses was both effective and generally well tolerated for patients with Zollinger-Ellison syndrome and idiopathic hypersecretion.     

Misdiagnosis of the Zollinger-Ellison syndrome due to hyperlipidemia

Most authorities feel that diagnosis of the Zollinger-Ellison syndrome is established when the serum gastrin level is greater than 1000 pg/mL (1000 ng/L) in a patient with gastric acid hypersecretion and clinical manifestations consistent with the diagnosis. A patient with recurrent peptic ulcer disease is reported who was thought to have had the Zollinger-Ellison syndrome based on two serum gastrin level measurements greater than 1000 pg/mL (1000 ng/L). Subsequent evaluation revealed the gastrin elevation to be spurious because the sample was hyperlipidemic. Lipemic serum samples may yield falsely elevated serum gastrin determinations as determined by radioimmunoassay.     

Gastric acid hypersecretory states: Recent insights and advances

Gastric acid hypersecretory states are characterized by basal hypersecretion of gastric acid and historically include disorders associated with hypergastrinemia, hyperhistaminemia, and those of unknown etiology. Although gastric acid secretion is infrequently measured, it is important to recognize the role of gastric hypersecretion in the symptoms of these disorders because they share several features of pathogenesis and treatment. In this article, recent important articles reporting insights into their diagnosis, pathogenesis, and treatment are reviewed. Particular attention is paid to Zollinger-Ellison syndrome, because it has the most extreme acid hypersecretion of this group of disorders and because numerous recent articles deal with various aspects of the diagnosis, molecular pathogenesis, and treatment of the gastrinoma itself or the acid hypersecretion. Two new hypersecretory disorders are reviewed: rebound acid hypersecretion after the use of proton pump inhibitors and acid hypersecretion with cysteamine treatment in children with cystinosis.     

Hypersecretory duodenal ulcer and Helicobacter pylori infection: a four-year follow-up study.

BACKGROUND: About 10% of duodenal ulcer patients are characterized by gastric acid hypersecretion with normal gastrin values. Relapsing duodenal ulcer after Helicobacter pylori cure has been related to high acid output and maintenance antisecretory therapy has been suggested in hypersecretory duodenal ulcer patients. The role of Helicobacter pylori infection and the effects of Helicobacter pylori cure in hypersecretory duodenal ulcer patients still remain to be fully studied. AIM: To study: a) whether gastric acid hypersecretion "per se" is a risk factor for duodenal ulcer recurrence; b) whether maintenance antisecretory therapy is necessary after eradication in hypersecretory duodenal ulcer patients. PATIENTS: The study population comprised 8 hypersecretory duodenal ulcer patients, selected from a population of 79 Helicobacter pylori-positive duodenal ulcer patients. METHODS: Hypersecretory duodenal ulcer patients were followed-up for at least 4 years after eradication. Gastric acid secretion was measured again 12 months after Helicobacter pylori eradication. Gastroscopy with histology was performed 3, 6, 12 and 36 months after treatment, 13C-urea breath test after 42 months; clinical questionnaires were completed every 6 months. RESULTS: After eradication, despite a not significantly reduced high acid output (median value of basal acid output and pentagastrin-stimulated acid output, respectively, 23.1 mEq/h and 64.1 mEq/h before treatment vs 16 mEq/h and 49.7 mEq/h 12 months after treatment), all patients were free from symptoms, none of them had duodenal ulcer relapse or complications (7/8 before treatment), or needed antisecretory maintenance therapy, except for one patient taking non-steroidal anti-inflammatory drugs. CONCLUSIONS: These findings, obtained in a selected population of hypersecretory duodenal ulcer patients with long-term follow-up, suggest that after successful Helicobacter pylori eradication gastric acid hypersecretion "per se" is not able to determine the recurrence of duodenal ulcer.     

The effect of Zollinger-Ellison syndrome and omeprazole therapy on gastric oxyntic endocrine cells.

In 1983, all trials of omeprazole in humans were stopped because rats given the drug developed gastric endocrine cell hyperplasia and carcinoid tumors. Further studies in rats showed that drug-induced achlorhydria and hypergastrinemia caused these changes. Because data in humans are limited, we compared the numbers of endocrine cells, as judged by silver staining (argyrophilia), in the gastric mucosa of patients with Zollinger-Ellison syndrome, who are hypergastrinemic, and in normogastrinemic patients with idiopathic acid-peptic diseases. In addition, we analyzed the number of gastric endocrine cells in patients with Zollinger-Ellison syndrome given omeprazole for up to 3 years. Patients with Zollinger-Ellison syndrome had 15.7% +/- 6.9% argyrophil cells in biopsies of gastric oxyntic mucosa, and patients with idiopathic acid-peptic disease had 7.8% +/- 2.3% (P less than 0.01). In patients with Zollinger-Ellison syndrome, the percentage of argyrophil cells was not related to serum gastrin concentration, duration of symptoms, time since diagnosis, basal or maximal acid output, extent of tumor, or age. There was a tendency for patients with multiple endocrine neoplasia type 1 to have a greater percent of argyrophil cells than patients with sporadic Zollinger-Ellison syndrome. Considering the biopsies from both normogastrinemic and hypergastrinemic patients, there was a significant relationship between the percentage of argyrophil cells and the serum concentration of gastrin (P less than 0.01). Patients with Zollinger-Ellison syndrome given omeprazole for up to 3 years developed no significant changes in percentage of argyrophil cells, no carcinoid tumors, and no changes in serum concentrations of gastrin. The present study shows that patients with Zollinger-Ellison syndrome have an increased percentage of argyrophil cells in oxyntic mucosa and that omeprazole does not increase this percentage. In periods of up to 3 years, omeprazole had no effects on gastric morphology in patients with Zollinger-Ellison syndrome.     

Marked hypergastrinemia in gastric outlet obstruction

We report a 45-year-old woman with chronic peptic ulcer disease and multiple episodes of bowel obstruction, who was admitted with gastric outlet obstruction. Because of gastric hypersecretion, a diagnosis of Zollinger-Ellison syndrome was suspected and an initial serum gastrin of 1,251 pg/ml supported this diagnosis. Subsequent evaluation failed to reveal a gastrinoma. A repeat serum gastrin level after 14 days of continuous nasogastric decompression was 43 pg/ml, suggesting that the initial hypergastrinemia was due to antral distention. It is important to consider the possibility of gastric outlet obstruction as a stimulus for serum gastrins in the range previously considered diagnostic for the Zollinger-Ellison syndrome.     

Therapy with gastrin antibody in the Zollinger-Ellison syndrome

The therapeutic effectiveness of parenterally administered rabbit antigastrin antibody was evaluated in a patient with the Zollinger-Ellison syndrome who had a fasting serum gastrin level of 3020 pg/ml and a basal gastric acid secretion of 48.9 mEq/hr. Control globulin reduced gastric secretion to 32 mEq/hr. Gastrin antibody reduced it further to 8.7 mEq/hr. Betazole hydrochloride which was given 75 min after administration of gastrin antibody stimulated acid secretion to 57.2 mEq/hr. One day later basal acid secretion was uninhibited although some antibody activity was present in the patient's serum. The results suggested that gastrin antibody acutely inhibited basal but not betazole-stimulated secretion.A portion of this paper was presented to the Gastroenterology session of the American Federation for Clinical Research, Southern Section, January 25, 1973.     

A nongastrin malignant ampullary tumor causing gastric acid and pepsin hypersecretion. A case report

We report a case of multiple duodenal ulcers with gastric hypersecretion due to a nongastrin secretagogue produced by a malignant tumor of the pancreas in a 78-year-old man. The case resembled a Zollinger-Ellison syndrome (ZES) with high acid output (basal acid output 27, sham meal-stimulated 37, maximum acid output 47 mEq/h), but with fasting gastrin 43 pg/ml, nonresponsive to secretin. As in ZES, pepsin output was comparatively low, and secretion was inhibitable by atropine (50% inhibited by 1 microM). The tumor removed at surgery contained less than 1 ng gastrin per gram, but was many times more potent than pentagastrin in stimulating acid from a lumen-perfused rat stomach. The tumor also contained cholecystokinin (CCK-8 and CCK-33), motilin, insulin, and somatostatin, which were also present in adjacent normal pancreas; in addition, the tumor contained pancreatic polypeptide and pancreatic cancer-associated antigen. This case represents a rare syndrome due to an as yet undefined peptide secreted by a (frequently malignant) pancreatic endocrine tumor and masquerading as ZES. This is the first report of studies of pepsin secretion and of the effect of atropine, suggesting that the physiologic effects of the secretagogue resemble that of gastrin.     

Hypergastrinemia of antral origin in duodenal ulcer

A case of recurrent duodenal ulcer, basal gastric hypersecretion, and hypergastrinemia of antral origin is presented. The diagnosis was suggested preoperatively by stimulation tests with secretin and food. Billroth II antrectomy led to normalization of serum gastrin within half an hour. The gastrin content of the antral mucosa was not increased, neither was antral G-cell hyperplasia demonstrable. Postoperatively the basal gastric acid output and fasting serum gastrin levels were normal, without a postprandial increase in serum gastrin concentrations. The case does not support the existence of a specific disease called antral G-cell hyperplasia.     

Hypergastrinaemia Due to an Excluded Gastric Antrum: A Proposed Method for Differentiation from the Zollinger-Ellison Syndrome

Summary: A case is presented of a patient with recurrent peptic ulceration due to an excluded gastric antrum. The patient demonstrated basal hypergastrinaemia and gastric secretory studies showed a high basal acid output with only a slight increase following pentagastrin stimulation. Intravenous secretin injection caused a marked fall in serum gastrin and gastric acid output in this patient. This is in contrast to two patients with Zollinger-Ellison syndrome in whom secretin produced a rise in serum gastrin; and one of these patients who had an intact stomach, also showed a rise in gastric acid output. It is suggested that gastrin and acid output measurement after secretin injection may provide a method of differentiation of an excluded gastric antrum from the Zollinger-Ellison syndrome.     

Validation of a new endoscopic technique to assess acid output in Zollinger-Ellison syndrome.

BACKGROUND & AIMS: To safely manage the hypersecretory state in patients with Zollinger-Ellison syndrome, both upper endoscopy and gastric analysis are required to titrate optimal medical therapy. Conventional gastric analysis requires more than 1 hour to perform and results in significant patient dissatisfaction. In this study, we have validated endoscopic gastric analysis as a novel technique that can effectively replace conventional gastric analysis. METHODS: In a prospective, cross-over study, 12 patients with Zollinger-Ellison syndrome underwent gastric analysis, first by the conventional method and then by an endoscopic technique performed on the same day. Acid concentration was determined by titration, volume output was recorded, and acid output was calculated using standard methodologies and formulas. Agreement was assessed following the Bland-Altman method. To assess repeatability, both techniques were repeated on the same day in a subset of patients. RESULTS: Excellent agreement was reported between acid output (95% limits of agreement, -1.27 to 1.61 mEq/h) and acid concentration (95% limits of agreement, -0.01 to 0.01 mEq/mL), although poor agreement was observed between volume output measured. Endoscopic gastric analysis showed greater reproducibility regarding acid and volume output measured. CONCLUSIONS: We introduce a new, rapid, reproducible, and accurate endoscopic technique to measure acid output in patients with Zollinger-Ellison syndrome who require both annual endoscopy and gastric analysis. The data presented here suggest that endoscopic gastric analysis would be equally effective in determining acid output in other hypersecretory states. Additional analysis of cost effectiveness is needed to evaluate its use as a screening tool in select populations.     

Ovarian carcinoma as a cause of Zollinger-Ellison syndrome. Natural history, secretory products, and response to provocative tests

Zollinger-Ellison syndrome is usually caused by a gastrin-secreting tumor in or near the pancreas. We describe a patient in whom an ovarian cystadenocarcinoma was the cause of the syndrome. The patient presented with a short history of peptic ulceration and development of a large pelvic mass. Investigations demonstrated a basal acid output of 37.8 mEq/h and a maximal acid output of 36.0 mEq/h, and the plasma concentration of gastrin was 830 pg/ml (normal less than 100). Secretin and calcium infusion tests were positive, and a meal test was compatible with Zollinger-Ellison syndrome. Imaging studies demonstrated a normal liver and pancreas but a large cystic right ovarian mass. Resection of the mass resulted in a marked reduction in gastric acid output, a fall in plasma gastrin concentration to normal, negative calcium and secretin tests, and a normal (positive) meal test. Histology of the mass showed it to be a mucinous cystadenocarcinoma. The tumor stained with immunoperoxidase technique was positive for gastrin, and the cyst fluid contained high concentrations of gastrin and calcitonin. One year later, the patient has no biochemical or imaging evidence of tumor. Ovarian, gastrin-producing tumors and pancreatic gastrinomas cannot be distinguished by provocative tests, and negative imaging studies do not exclude a pancreatic tumor. Patients with an ovarian mass and Zollinger-Ellison syndrome should have a bilateral oophorectomy and a careful exploration of the pancreatic area.     

Intravenous omeprazole in patients with Zollinger-Ellison syndrome undergoing surgery

Twenty patients with Zollinger-Ellison syndrome who were undergoing surgery were studied prospectively to assess the efficacy and safety of IV omeprazole. During the preoperative period, in 19 of 20 patients, omeprazole 60 mg administered as an IV bolus every 12 hours inhibited acid output to less than 5 mEq/h measured in the last hour before the next dose of drug. In one patient, acid output was 25 mEq/h 12 hours after omeprazole, 60 mg, and increasing the dose to 100 mg every 12 hours reduced acid output to less than 5 mEq/h. During the operative and postoperative periods, IV omeprazole controlled gastric acid hypersecretion in all patients for up to 15 days. During this time, all patients received the dose determined preoperatively. No patient developed any clinical, hematological, or biochemical toxicity that could be attributed to omeprazole therapy during the preoperative or postoperative period. The present study demonstrates that omeprazole administered by IV bolus is safe and effective for controlling gastric acid hypersecretion. In contrast to IV histamine H2-receptor antagonists, IV omeprazole has the advantages of not requiring continuous infusion or postoperative dose adjustments. Intravenous omeprazole will become the drug of choice in patients with Zollinger-Ellison syndrome undergoing surgery.     

Sensitivity, specificity and predictive values of the secretin infusion test in the diagnosis of gastrinoma

From 1974 to 1981, 55 patients, 18 with Zollinger-Ellison syndrome (ZES) histologically confirmed and 37 patients with duodenal ulcer (DU) without pylorostenosis were followed for a minimal period of 5 years. The diagnostic values of a) basal acid output (BAO mEq/h); b) 60 min acid output after secretin infusion, 3 CU-GIH/kg, (MAO-SE mEq/h); c) basal serum gastrin (BSG pg/ml: mean of 4 gastrin determinations) and d) serum gastrin after secretin (SG-SE pg/ml: mean of 4 gastrin determinations during secretin infusion) were calculated. Cut off point values of 100 p. 100 specificity (i. e. no DU patient reached these values) with a positive predictive value of 100 p. 100 (i. e. probability for gastrinoma when this cut off point was attained) were BAO greater than 26 mEq/h, MAO-SE greater than 18 mEq/h, BSG greater than 221 pg/ml, SG-SE greater than 186 pg/ml. The sensitivities of these parameters (i. e. percent of ZES which reached the given cut off point) were respectively (p. 100): 39, 78, 72 and 94. Ranking these parameters according to their own discriminative value expressed by R2 (square correlation coefficient) gave SG-SE, R2 = 0.559; BSG, R2 = 0.508; MAO-SE, R2 = 0.456; BAO, R2 = 0.414. The most discriminative association of 2 variables was SG-SE and MAO-SE (R2 = 0.650). Association of SG-SE, MAO-SE and BAO or BSG (or BAO and BSG) did not increase significantly the discrimination between ZES and DU (R2 = 0.672).     

Current concepts on physiological control of gastric acid secretion. Clinical applications.

Gastric acid secretion by the parietal cell is a single digestive process involving a continuous interplay between nervous and hormonal stimuli. Gastric acid hypersecretion and hypergastrinemia may represent pathologic disturbance of the normal "gastric phase" of acid secretion (excluded antrum syndrome) or abnormal gastrin secretion from a nongastric source as in the Zollinger-Ellison syndrome. Diagnosis of these two syndromes preoperatively is dependent on immunoassay for serum gastrin. A fall in serum gastrin level after the injection of secretin will distinguish the excluded antrum syndrome from the Zollinger-Ellison syndrome. Which hormone or hormones cause the acid hyposecretion of the watery diarrhea hypokalemia achlorhydria syndrome is still uncertain. Potential candidates include secretin, glucagon (alone or combined with gastrin), vasoactive intestinal peptide and gastric inhibitory polypeptide. Secretin has undergone trials as therapy in peptic ulcer whereas glucagon is under investigation for the treatment of acute pancreatitis because of its dual actions as (1) an enterogastrone and (2) an inhibitor of pancreatic secretion.     

Long-term efficacy and safety of omeprazole in patients with Zollinger-Ellison syndrome: a prospective study

To determine the long-term efficacy, safety, and toxicity of omeprazole, we studied 40 patients with Zollinger-Ellison syndrome given omeprazole for 6-51 mo (median 29). The mean daily dose of omeprazole required to control gastric acid secretion was 82 +/- 31 mg. Thirty-one patients required omeprazole once per day. In 9 patients acid output was not controlled by 120 mg once per day, but was controlled by 60 mg every 12 h. The daily dose of omeprazole correlated with the previous dose of histamine H2-receptor antagonist (r = 0.89, p less than 0.001), basal acid output (r = 0.43, p less than 0.01), and maximal acid output (r = 0.39, p less than 0.02) but not with serum concentration of gastrin (r = -0.32). Increases in the dose of omeprazole were required in 9 patients. Twenty-nine patients had mild peptic symptoms with acid outputs less than 10 mEq/h while taking histamine H2-receptor antagonists. Symptoms resolved completely in 23 patients and partially in 3 when taking omeprazole. Omeprazole prevented mucosal disease in all patients including 17 in whom histamine H2-receptor antagonists had produced only partial resolution despite acid output being less than 10 mEq/h and in those with symptoms during omeprazole therapy. Omeprazole therapy was not associated with any significant side effects, nor with any evidence of hematologic or biochemical toxicity. Serum concentrations of gastrin did not change significantly during therapy. In 6 patients treated with omeprazole for 1 yr there was no change in basal or maximal acid output. In all patients, gastric morphology and histopathology demonstrated no evidence of gastric carcinoid formation. These results demonstrate that with long-term treatment of up to 4 yr, omeprazole is safe, with no evidence of hematologic, biochemical, or gastric toxicity. Furthermore, omeprazole remained effective, with only 23% of patients requiring an increase in dose, and continued to control symptoms in patients who had not been entirely symptom-free despite high doses of histamine H2-receptor antagonists. Omeprazole is now the drug of choice in patients with Zollinger-Ellison syndrome.     

Gastric acid and pancreatic polypeptide responses to modified sham feeding: indication of an increased basal vagal tone in a subgroup of duodenal ulcer patients.

The effect of sham feeding upon gastric acid secretion and pancreatic polypeptide release was investigated in 28 patients with duodenal ulcer in order to evaluate whether high basal vagal activity is the cause of basal acid hypersecretion in patients with duodenal ulcer and basal secretion higher than 30% of their peak acid output. The patients were divided into two groups based on the ratio of basal/pentagastrin stimulated peak acid output (BAO/PAO) was higher or lower than 0.30: group A n = 19 (BAO/PAO less than or equal to 0.30) and group B n = 9 (BAO/PAO greater than 0.30). Gastric acid response to sham feeding (SAO) was significantly higher than basal level in group A (SAO: 11.4 mEq/h (2.5-20.1) vs BAO: 5.2 mEq/h (0.8-22.9), p less than 0.01, median (range)) while in group B the acid secretion did not increase with sham feeding (SAO: 9.6 mEq/h (4.5-13.6) vs BAO: 8.8 mEq/h (6.3-13.8) ns, median (range)). A negative correlation (r= -0.6118226, p less than 0.01) was found between acid increase expressed as basal subtracted sham feeding response (SAO-BAO) and BAO/PAO ratio of the entire group of duodenal ulcer patients (n = 28) suggesting that the greater is basal acid secretory capacity the smaller is acid increase in response to residual vagal activation. Pancreatic polypeptide response to sham feeding was higher in group A than in group B but no correlation (r = 0.20, n = 28) nor individual covariation was found between acid and pancreatic polypeptide secretions during vagal stimulation. sham feeding did not change serum gastrin. It is concluded that an increased vagal stimulation seems to be the cause of basal hypersecretion in a subgroup of patients with duodenal ulcer. The lact of correlation between the pancreatic polypeptide and acid responses to vagal stimulation interferes with the reliability of pancreatic polypeptide as indicator of vagal tone on gastric parietal cells.