Effects of bombesin on gastrin and gastric acid secretion in patients with duodenal ulcer

Changes of Gastric Secretion after Bolus and Slow Intravenous Administration of Bombesin and Neurotensin

Objectives:The aim of the present study was to evaluate the changes caused by intravenous administration of regulatory peptides, bombesin (BBS) and neurotensin (NT), on gastric secretion, serum gastrin, and plasma levels of bombesin-1ike immunoreactivity (BLI) and neurotensin. Materials and methods: Fourteen dogs underwent an upper gastrointestinal tract operation and a Pavlov pouch for the concentration of gastric fluids was formed. The experimental animals were divided into two groups. Peptides were given one month after the second operation and after fasting for 12 hours. In group A, the effects of BBS were studied after a rapid 1 ìg/kg body weight dose and a slow 30´ 0.5 ìg/kg body weight dose administration intravenously. Correspondingly to group B the effects of NT were studied in the same way. Results:The rapid intravenous infusion of BBS caused a very significant increase in gastrin levels, BLI in plasma, volume and HCl of the gastric fluids. The same results, plus a significant decrease in gastric pH, were observed following slow intravenous infusion of BBS. Concerning the NT, rapid administration caused a significant decrease in the volume of gastric fluids. Slow NT administration of caused a significant reduction in gastric fluid volume and in HCl. On the contrary, pH was significantly increased. Conclusion:Bombesin increases plasma gastrin levels and HCl secretion. Neurotensin administration causes a decrease in HCl secretion without affecting gastrin levels in plasma.

Localization of 99mTc-GRP Analogs in GRPR-Expressing Tumors: Effects of Peptide Length and Neprilysin Inhibition on Biological Responses

The overexpression of gastrin-releasing peptide receptors (GRPRs) in frequently occurring human tumors has provided the opportunity to use bombesin (BBN) analogs as radionuclide carriers to cancer sites for diagnostic and therapeutic purposes. We have been alternatively exploring human GRP motifs of higher GRPR selectivity compared to frog BBN sequences aiming to improve pharmacokinetic profiles. In the present study, we compared two differently truncated human endogenous GRP motifs: GRP(14–27) and GRP(18–27). An acyclic tetraamine was coupled at the N-terminus to allow for stable binding of the SPECT radionuclide ^99mTc. Their biological profiles were compared in PC-3 cells and in mice without or with coinjection of phosphoramidon (PA) to induce transient neprilysin (NEP) inhibition in vivo. The two ^99mTc-N₄-GRP(14/18–27) radioligands displayed similar biological behavior in mice. Coinjection of PA exerted a profound effect on in vivo stability and translated into notably improved radiolabel localization in PC-3 experimental tumors. Hence, this study has shown that promising ^99mTc-radiotracers for SPECT imaging may indeed derive from human GRP sequences. Radiotracer bioavailability was found to be of major significance. It could be improved during in situ NEP inhibition resulting in drastically enhanced uptake in GRPR-expressing lesions.

Gastrin releasing peptide receptor-directed radioligands based on a bombesin antagonist: synthesis, (111)in-labeling, and preclinical profile

Novel bombesin (BBN) antagonists were synthesized by coupling the chelator 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) to H-d-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2 (JMV594) through linkers of increasing number of (βAla)x residues (x = 1-3). Labeling with (111)In afforded the respective radiotracers in high purity and high specific activity. Bioconjugate affinity for the gastrin releasing peptide receptor (GRPR) as determined against [(125)I-Tyr(4)]BBN was high (IC50 values in the lower nanomolar range). Radioligands poorly internalized in PC-3 cells at 37 °C. Radiopeptides remained >60% intact 5 min after entering the bloodstream of healthy mice. After injection in SCID mice bearing human PC-3 xenografts all analogues showed high tumor uptake and rapid background clearance via the kidneys into urine. Interestingly, pancreatic uptake, albeit GRPR-specific, declined rapidly with time. (111)In-DOTA-(βAla)2-JMV594 achieved the highest tumor values among the group (17.0 ± 2.8%ID/g vs. 8-10%ID/g, respectively, at 4 h pi) indicating that the (βAla)2-linker favors in vivo interaction of radiopeptides with the GRPR.

Review article: Strategies to determine whether hypergastrinaemia is due to Zollinger-Ellison syndrome rather than a more common benign cause

BACKGROUND

As there is considerable overlap between the fasting serum gastrin concentrations found in Zollinger-Ellison syndrome and various common conditions such as Helicobacter pylori infection and acid suppressing medication use, establishing the cause of hypergastrinaemia in individual cases can sometimes be difficult.

AIM

To review the causes of hypergastrinaemia and the role of additional non-invasive investigations in hypergastrinaemic patients.

METHODS

Review of articles following a Pubmed search.

RESULTS

As gastrinomas may cause serious complications and be potentially life threatening, investigation of hypergastrinaemic patients should particularly focus on confirming or refuting the diagnosis of Zollinger-Ellison syndrome. Establishing the cause of hypergastrinaemia may be difficult when there is only a mild-to-moderate elevation of fasting serum gastrin concentration and concurrent treatment with proton pump inhibitor drugs and the presence of H. pylori infection can both confuse the clinical picture. A variety of provocative tests are therefore useful for establishing whether a hypergastrinaemic patient has a gastrinoma and current evidence suggests that the secretin test should be used first line.

CONCLUSIONS

We suggest an algorithm for the investigation of patients found to have an elevated fasting serum gastrin concentration and address the roles of gastrin stimulation tests in current clinical practice.

Food fight! Parenteral nutrition, enteral stimulation and gut-derived mucosal immunity

INTRODUCTION

Nutrition support is an integral component of modern patient care. Type and route of nutritional support impacts clinical infectious outcomes in critically injured patients.

DISCUSSION

This article reviews the relationships between type and route of nutrition and gut-derived mucosal immunity in both the clinical and laboratory settings.

Lack of specific association between gastric autoimmunity hallmarks and clinical presentations of atrophic body gastritis

AIM: To investigate the possible relationships between gastric autoimmune phenomena and clinical presentations of this disorder, in consecutive atrophic body gastritis patients.

METHODS: A total of 140 atrophic body gastritis patients, diagnosed as consecutive outpatients presenting with macrocytic or iron deficiency anemia, or longstanding dyspepsia underwent gastroscopy with antral and body biopsies, assay of intrinsic factor, parietal cells and Helicobacter pylori (H pylori) antibodies. Gastritis was assessed according to Sydney System.

RESULTS: Parietal cell antibodies were equally distributed in all clinical presentations, whereas the positivity of intrinsic factor antibodies (49/140, 35%) was significantly higher in pernicious anemia patients (49.2%) than in iron deficiency (21.1%) and dyspeptic patients (27.8%). No specific pattern of autoantibodies was related to the clinical presentations of atrophic body gastritis. A positive correlation was obtained between the body atrophy score and the intrinsic factor antibody levels (r = 0.2216, P = 0.0085). Associated autoimmune diseases were present in 25/140 (17.9%) patients, but the prevalence of autoimmune diseases was comparable, irrespective of the clinical presentations.

CONCLUSION: The so-called hallmarks of gastric autoimmunity, particularly in intrinsic factor antibody cannot be usefully employed in defining an autoimmune pattern in the clinical presentations of ABG.

Co-existence of hyperparathyroidism, hypergastrinaemia and multiple gastric carcinoids is not always due to incomplete expression of the MEN-1 syndrome

Until recently, the association of primary hyperparathyroidism and gastric carcinoid, with or without hypergastrinaemia, had been considered an incomplete form of multiple endocrine neoplasia type 1. This is because it seemed unlikely that the rare joint appearance of these diseases could occur only by chance. It is now possible to evaluate the pathogenetic involvement of the multiple endocrine neoplasia type 1 gene in many, apparently sporadic, clinical conditions. This is a case report of a female mimicking multiple endocrine neoplasia type 1 due to the presence of hyperparathyroidism, gastric carcinoid, and hypergastrinaemia. However, involvement of the MEN-1 gene (exons 2-10) was not detected, whereas hypergastrinaemia was attributed to a chronic atrophic gastritis.

The long-term effects of cure of Helicobacter pylori infection on patients with atrophic body gastritis

BACKGROUND

Helicobacter pylori infection induces atrophic body gastritis, but the long-term effect of its cure on body atrophy is unclear.

AIM

To investigate the long-term effects of H. pylori cure on gastric morpho-functional parameters in patients with atrophic body gastritis.

METHODS

Forty patients with atrophic body gastritis were cured of H. pylori infection. Gastroscopy with biopsies, gastrin and pepsinogen I levels and basal and stimulated acid secretion were evaluated before and 6-12 months after treatment.

RESULTS

At eradication assessment (6-12 months), in eight of the 40 patients, body atrophy was no longer observed, whereas in 32 of the 40 it remained substantially unchanged (2.03 +/- 0.12 vs. 1.83 +/- 0.15). In the eight patients with reversed body atrophy, gastrinaemia decreased significantly with respect to pre-treatment values (265 +/- 59.9 pg/mL vs. 51.8. +/- 6.04 pg/mL), and basal and stimulated acid secretion increased significantly after cure. In the 32 patients still presenting body atrophy, gastrinaemia was similar topre-treatment values (457 +/- 76.04 pg/mL vs. 335.1 +/- 58.8 pg/mL). At follow-up (21-25 and 32-70 months), the eight patients with reversed body atrophy continued with normal gastrinaemia (35.3 +/- 10.1 pg/mL vs. 38.5 +/- 8.8 pg/mL), but in the 19 patients with continued atrophy, both corporal atrophy and intestinal metaplasia remained substantially unchanged.

CONCLUSIONS

Following successful treatment in patients with atrophic body gastritis and H. pylori infection, long-term histological investigations are crucial in order to detect reversed body damage or to confirm continued body atrophy.

Progression of gastric enterochromaffin-like cells growth in Zollinger-Ellison syndrome and atrophic body gastritis patients

BACKGROUND

Enterochromaffin-like cell hyperplasia of the gastric body mucosa occurs in hypergastrinaemic conditions such as atrophic body gastritis and Zollinger-Ellison syndrome. However, the time course of change or factors involved are not known.

AIMS

To compare the rate of change of enterochromaffin-like cell proliferation in patients with atrophic body gastritis and Zollinger-Ellison syndrome.

PATIENTS

From a consecutive series of atrophic body gastritis and Zollinger-Ellison syndrome patients, studied at the time of first diagnosis, 10 atrophic body gastritis (4 with pernicious anaemia) and 14 Zollinger-Ellison syndrome (4 with multiple endocrine neoplasia type 1) patients were followed-up for a median time of 48 months.

METHODS

At entry and during follow-up patients underwent: plasma gastrin determination, endoscopic sampling of body mucosa for qualitative assessment of enterochromaffin-like cell hyperplasia pattern and degree of glandular atrophy, qualitative and morphometric analyses of body mucosa endocrine cells.

RESULTS

At time of diagnosis, enterochromaffin-like cell lesions were more severe in atrophic body gastritis than in Zollinger-Ellison syndrome. During follow-up, no significant variations were observed in gastrin values, enterochromaffin-like cell patterns and grade of body mucosa atrophy in atrophic body gastritis. In contrast, gastrin levels were significantly increased [median 1200 (235-2625) vs 1947 (225-5200) pg/ml; p<0.001)] as was total volume density of enterochromaffin-like cells [median 1.60 (0.53-4.06) vs 3.18 (1.35-21.13)% of mucosal epithelial component; (p<0.005)] in Zollinger-Ellison syndrome. Micronodular hyperplasia of enterochromaffin-like cells, present in only one patient at diagnosis, was observed in 8 Zollinger-Ellison syndrome patients at follow-up.

CONCLUSIONS

These data suggest that the progression of enterochromaffin-like cell growth in human gastric mucosa requires an increase of and/or a prolonged exposure to severe hypergastrinaemia.

Atrophic body gastritis patients with enterochromaffin-like cell dysplasia are at increased risk for the development of type I gastric carcinoid

BACKGROUND/AIMS

In the presence of atrophic body gastritis, gastric carcinoid develops from gastric-body mucosa enterochromaffin-like cells. Few data exist on the prevalence of enterochromaffin-like dysplastic lesions in atrophic body gastritis patients and their presumed risk of evolution to carcinoid has never been assessed prospectively in humans. The aim of the present study was to investigate the prevalence and incidence of dysplastic and neoplastic enterochromaffin-like cell lesions in a consecutive series of patients with atrophic body gastritis.

METHODS

A total of 130 atrophic body gastritis patients at diagnosis and 96 atrophic body gastritis patients at follow-up (median 30 months) underwent gastroscopy with multiple biopsies and fasting gastrinaemia evaluation. In patients with enterochromaffin-like cell dysplasia, a more detailed bioptic sampling at follow-up was performed.

RESULTS

Of the 130 atrophic body gastritis patients, only one (0.7%) had a gastric carcinoid polyp, whereas enterochromaffin-like cell dysplasia was found in five patients (3.8%). At follow-up only one out of the 96 atrophic body gastritis patients (1%) was diagnosed as having a carcinoid polyp at 41 months. Enterochromaffin-like cell dysplasia was present in four additional patients (4.2%). Two atrophic body gastritis pernicious anaemia patients with enterochromaffin-like cell dysplasia developed a gastric carcinoid in the follow-up. Among nine atrophic body gastritis patients with enterochromaffin-like cell dysplasia, the incidence of carcinoid tumour was 22% compared to 1.1% of atrophic body gastritis patients without dysplasia (odds ratio: 26.00; 95% confidence interval: 2.089-323.52). During the follow-up, fasting gastrin levels increased significantly only in atrophic body gastritis patients with enterochromaffin-like cell dysplasia (mean 677.4 +/- 66.1 vs 1112.2 +/- 185.6; P = 0.0287).

CONCLUSION

This study provides the first clinical evidence that, in hypergastrinaemic atrophic body gastritis patients, enterochromaffin-like cell dysplasia carries a markedly increased risk for development of type I gastric carcinoid. This suggests that a more detailed endoscopic/bioptic procedure in this subgroup of atrophic body gastritis patients is able to detect gastric carcinoid at an early stage.

Involvement of the corporal mucosa and related changes in gastric acid secretion characterize patients with iron deficiency anaemia associated with Helicobacter pylori infection

BACKGROUND

Recent studies have reported an association between iron deficiency anaemia and Helicobacter pylori. Helicobacter pylori could cause iron deficiency anaemia by altering iron absorption. We observed that most patients with Helicobacter pylori infection and iron deficiency anaemia present a chronic superficial pangastritis.

AIM

To investigate whether Helicobacter pylori-positive patients with iron deficiency anaemia have peculiar histological and functional features when compared with non-anaemic Helicobacter pylori-positive subjects.

PATIENTS

Fifty-one patients with iron deficiency anaemia, in whom chronic superficial Helicobacter pylori gastritis was the only gastrointestinal finding, and 103 non-anaemic Helicobacter pylori-positive controls were included in the study. Thirty-seven patients were randomly matched with 37 controls of the same sex and age.

METHODS

Gastroscopy, with antral (n=3) and body (n=3) biopsies, was performed. Gastrin and pepsinogen I levels and antiparietal cell antibodies were evaluated. Intragastric pH was also measured.

RESULTS

Gastritis involved the corporal mucosa in 90% of patients compared to 42.7% of controls (P < 0.0001). The mean inflammatory score in the gastric body was significantly higher among patients than in controls (2.2 vs. 0.6; P=0.012). Gastrin was significantly higher in patients than in controls (mean 60.2 vs. 29 pg/mL; P=0.0069). Intragastric pH was higher in patients than in controls (median 5.7 vs. 2; P=0.0026).

CONCLUSIONS

These data suggest that patients with iron deficiency anaemia and Helicobacter pylori infection have a peculiar pattern of gastritis with corporal involvement and related changes in intragastric pH.

Two-thirds of atrophic body gastritis patients have evidence of Helicobacter pylori infection

BACKGROUND

Helicobacter pylori is involved in the induction of atrophic body gastritis (ABG). During the progression of atrophic gastritis the disappearance of H. pylori has been documented and in time serology is the only sign that indicates a previous infection. It has been shown that a positive serology, in ABG patients without histological evidence of infection, indicates an active H. pylori infection.

AIM

To investigate in a population of patients with ABG the prevalence of H. pylori infection on the basis of histology and serology.

PATIENTS

A total of 150 consecutive outpatients with atrophic body gastritis were diagnosed on the basis of a screening system.

METHODS

All patients had a detailed assessment including measurement of specific anti-H. pylori antibodies, parietal cell antibodies, and fasting gastrin, gastroscopy with biopsies from gastric antrum and body.

RESULTS

24.6% of patients were histologically and serologically negative (Group A). 52.7% H. pylori was not detected on histology but IgG to H. pylori were in all these patients elevated (Group B). 22.6% of patients were found to be positive at histology in the corpus mucosa; all but one of these patients had elevated circulating IgG to H. pylori (Group C). Mean corporal atrophy score in Group B patients was statistically lower than in Group A patients (2.43 +/- 0.08 vs. 2.75 +/- 0.09; p <.05), but was statistically higher than in Group C patients (1.79 +/- 0.11; p <.001). Thus, in corporal mucosa a gradient of atrophy was shown: Group C < Group B < Group A. A similar gradient was observed for the presence of pernicious anemia being lowest in Group C 11.8% increasing to 45.6% in Group B and being highest in Group C 75.6%. A statistical correlation was obtained (r =.04791, p <.05) between the histological score of corporal atrophy and the titer of antibodies to parietal cells and an inverse correlation was obtained (r = -.2322, p <.0001) between the histological score of corporal atrophy and IgG to H. pylori.

CONCLUSION

This study shows that two-thirds of ABG patients have evidence of H. pylori infection. This suggests that atrophic gastritis of the corpus is a spectrum of damage where H. pylori is a key agent able to induce gastric atrophic damage and also gastric autoimmunity.

First endoscopic-histologic follow-up in patients with body-predominant atrophic gastritis: when should it be done?

BACKGROUND

Body-predominant atrophic gastritis is considered a risk factor for gastric cancer and carcinoid. Timing of follow-up for patients with this disorder has not been defined. This study was undertaken to determine the optimal time for the first endoscopic/histologic follow-up in patients with body-predominant atrophic gastritis.

METHODS

Forty-two patients with body-predominant atrophic gastritis were randomly assigned to 1 of 2 follow-up intervals: group A (n = 22) at 24 months and group B (n = 20) at 48 months. At baseline and follow-up patients underwent gastroscopy at which biopsies were obtained from the antrum and body for histopathology and evaluation for enterochromaffin-like cells.

RESULTS

In group A patients, 2 antral hyperplastic polyps (9.1%) were present at baseline and 4 antral hyperplastic polyps (18.2%) were found at follow-up. In group B patients, baseline gastroscopy revealed 2 antral hyperplastic polyps (10%) and follow-up 2 antral hyperplastic polyps (10%) and 1 carcinoid tumor (5%) in the body. Atrophy and intestinal metaplasia scores in gastric body and antral mucosa in both groups did not change significantly between baseline and follow-up, except an increase in antral mucosa atrophy in group B patients (p = 0.02) was revealed.

CONCLUSIONS

The results of this study indicate that performing the first follow-up in patients with body-predominant atrophic gastritis need not be earlier than at 4 years after diagnosis. This interval is satisfactory for detection of potential neoplastic lesions.

Role of Helicobacter pylori infection in pernicious anaemia

BACKGROUND

Pernicious anaemia is associated with atrophic body gastritis and considered an autoimmune disease. Whether Helicobacter pylori is involved in the induction of pernicious anaemia is uncertain.

AIMS

To investigate the prevalence of Helicobacter pylori infection in pernicious anaemia patients and to ascertain whether the Helicobacter pylori-positive patients had distinctive clinical and gastric morphofunctional characteristics.

PATIENTS AND METHODS

A series of 81 consecutive pernicious anaemia patients underwent serological, functional and endoscopic/histological investigations.

RESULTS

A total of 49 (60.5%) patients were Helicobacter pylori-positive (males 61.2% vs females 38.8%). No difference was observed in clinical and morphofunctional characteristics between Helicobacter pylori-positive and negative patients, whereas distinctive functional/histological features between histologically Helicobacter pylori-positive (n=8) and serologically Helicobacter pylori-positive (n=41) cases were detected. In the histologically Helicobacter pylori-positive group, Pepsinogen I was higher [13 (058) vs 5 (0-26) ng/ml; p=0.0025)] and positivity for anti-parietal cell antibodies was lower [42.9% vs 76.9, p=0.0867]. Antral histological variables of the gastritis score were significantly higher in the histologically Helicobacter pylori-positive than in the serologically Helicobacter pylori-positive patients, but this latter group had a higher score of body atrophy (2.63+/-0.12 vs 1.71+/-0.29; p=0.0051). Body inflammation was also significantly higher in the histologically Helicobacter pylori-positive group (chronic inflammation: 1.43+/-0.2 vs 1.05+/-0.06; p=0.0271; inflammation acitivity: 0. 57+/-0.3 vs 0.15+/-0.06, p=0.0220). Antral mucosa was normal in 24/41 (58.5%) of the serologically Helicobacter pylori-positive patients, but only in 1/8 (12.5%) of the histologically Helicobacter pylori-positive patients (p=0.0232).

CONCLUSIONS

Almost two thirds of pernicious anaemia patients have evidence of Helicobacter pylori, but only those with an active Helicobacter pylori infection have distinctive functional and histological features. These findings support the hypothesis that Helicobacter pylori infection could play a triggering role in a subgroup of pernicious anaemia patients.

Cure of Helicobacter pylori infection in atrophic body gastritis patients does not improve mucosal atrophy but reduces hypergastrinemia and its related effects on body ECL-cell hyperplasia

BACKGROUND

The effects of H. pylori eradication on atrophic body gastritis are controversial.

AIM

To investigate the effect of triple therapy on atrophic body gastritis in H. pylori-positive patients and its effect on morpho-functional gastric parameters.

METHODS

Thirty-five consecutive atrophic body gastritis patients with histological/serological evidence of H. pylori infection were treated. Before and 6 and 12 months after H. pylori eradication the patients were evaluated for fasting gastrinemia and pepsinogen I, basal and peak acid output, and detailed histological assessment including the ECL cell proliferative patterns.

RESULTS

Six months after treatment, 25 out of 32 patients were cured (78%). Cure of infection was associated with improvement in both basal (basal acid output mean 0.23 +/- 0.14 mmol/h vs. 1.75 +/- 0.7 mmol/h, P < 0.005) and stimulated acid secretion (peak acid output mean 3.0 +/- 1.06 mmol/h vs. 16.6 +/- 4.1 mmol/h, P=0.0017) as well as with reduction in hypergastrinemia (mean gastrin levels 444.1 +/- 110.7 pg/mL vs. 85.3. +/- 28 pg/mL; P < 0.005). In contrast, the eradication had no effect on body corporal atrophy and intestinal metaplasia, or pepsinogen I levels (mean 16.6 +/- 2.9 ng/mL vs. 14.2 +/- 2.1 ng/mL, N.S.). These results were confirmed at 12 months after eradication. A statistical inverse correlation was obtained (r=-0.3635, P < 0.05) between the corporal chronic infiltrate score and peak acid output values. A total of 53% of atrophic body gastritis patients showed a regression in severity of body ECL cell hyperplastic change.

CONCLUSION

Cure of H. pylori infection in patients with atrophic gastritis reverses some adverse effects on gastric function and ECL cell hyperplasia. H. pylori infection may be cured in atrophic body gastritis patients with partial reversion of its negative consequences on acid secretion and body ECL cell hyperplasia.

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.

Lansoprazole versus omeprazole for duodenal ulcer healing and prevention of relapse: a randomized, multicenter, double-masked trial

The aim of this randomized, multicenter, double-masked, parallel-group study was to compare the efficacy of lansoprazole with that of omeprazole monotherapy in duodenal ulcer healing and prevention of relapse. A total of 251 patients with duodenal ulcer were treated with either lansoprazole 30 mg/d (n = 167) or omeprazole 40 mg/d (n = 84). Patients with healed ulcers were then randomly allocated to 12 months of maintenance therapy with lansoprazole 15 mg/d (n = 74), lansoprazole 30 mg/d (n = 71), or omeprazole 20 mg/d (n = 73). Healing rates at 4 weeks (intent-to-treat analysis) were 93.9% (95% confidence interval [CI], 90.2% to 97.6%) with lansoprazole and 97.5% (95% CI, 93.7% to 100%) with omeprazole; there were no significant differences between groups. Endoscopic relapse rates after 6 months were 4.5% (95% CI, 0% to 10.6%) with lansoprazole 15 mg, 0% with lansoprazole 30 mg, and 6.3% (95% CI, 1.5% to 12.5%) with omeprazole 20 mg, compared with 3.3% (95% CI, 0% to 8.2%), 0%, and 3.5% (95% CI, 0% to 8.8%), respectively, at 12 months. Again, there were no significant differences between groups. The incidence of adverse events during acute treatment was 6.0% and 7.1% in the lansoprazole and omeprazole groups, respectively; during maintenance therapy, the incidences were 12.2% (lansoprazole 15 mg), 5.6% (lansoprazole 30 mg), and 11.0% (omeprazole 20 mg). Within treatment groups, pain was significantly ameliorated after the acute phase but not after maintenance therapy (P < 0.05); no differences were observed between groups. Gastrin values increased significantly after acute therapy (P < 0.05), persisted at these increased levels during maintenance therapy, and returned to normal after 6-month follow-up. Both lansoprazole and omeprazole were highly effective and well tolerated in the treatment of duodenal ulcer; relapse rates were similar for all doses studied. Thus no additional benefit is to be gained from using a proton-pump inhibitor at a dose > 15 mg lansoprazole to prevent relapse.

High prevalence of atrophic body gastritis in patients with unexplained microcytic and macrocytic anemia: a prospective screening study

OBJECTIVE

Atrophic body gastritis (ABG) is characterized by atrophy of the gastric body mucosa, hypergastrinemia, and hypo/achlorhydria. Its association with pernicious anemia is well recognized. Gastric hypo/achlorhydria is known to affect iron absorption but ABG is rarely considered as a possible cause of iron deficiency (microcytic) anemia. The aims of this study were to validate a screening methodology for the detection of ABG in a consecutive series of patients with microcytic and macrocytic anemia and to investigate the clinical and gastric morphofunctional characteristics of the two hematological presentations of ABG.

METHODS

A two-part prospective study was carried out. Part A aimed to validate the screening methodology to detect the presence of ABG in patients with macrocytic and microcytic anemia who have no specific GI symptoms, by measuring their gastrin levels and verified by performing gastroscopy with biopsy. Part B aimed to detect the presence of ABG in a larger sample of anemic patients by our validated method and, by pooling the data of ABG patients, to determine the clinical, gastric histological, and functional characteristics pertaining to the macrocytic and microcytic presentations of ABG.

RESULTS

In part A, ABG was detected in 37.5% of patients with macrocytic and in 19.5% of those with microcytic anemia. Pooling the data of the ABG patients from part A and part B, microcytic ABG patients were on average 20 yr younger than those with macrocytic anemia. The majority of microcytic ABG patients were female, most of whom were premenopausal. H. pylori infection was widely represented in the microcytic ABG group (61.1%). They also had a lesser grade of body mucosal atrophy and lower hypergastrinemia levels, suggesting a less severe oxyntic damage of shorter duration.

CONCLUSIONS

Macrocytic anemia is not the only hematological presentation of ABG. Physicians evaluating patients with unexplained iron deficiency anemia should consider ABG as a possible cause by determining fasting gastrin levels and performing gastroscopy with biopsies of the body mucosa.

Relationship between fundic endocrine cells and gastric acid secretion in hypersecretory duodenal ulcer diseases

BACKGROUND

Acid hypersecretion is associated with duodenal ulcer disease in the following conditions: Zollinger-Ellison syndrome (ZES) and antral gastrin cell hyperfunction (AGCH) due to hypergastrinaemia, or hypersecretory duodenal ulcer (HDU) without hypergastrinaemia.

AIM

To evaluate whether quantitative changes in fundic ECL and D cells may be involved in acid hypersecretion.

PATIENTS AND METHODS

Seven ZES, six AGCH and six HDU Helicobacter pylori-positive patients were compared. Basal (BAO) and pentagastrin-stimulated gastric acid secretions (PAO), and morphometry of fundic ECL and D cells were performed. The six AGCH and six HDU patients were investigated again using the same tests 1 year after H. pylori eradication.

RESULTS

Median PAO values were no different in all the hypersecretory conditions studied. The median volume density of ECL cells in ZES was significantly higher than in controls (2.75, range 1.74-5.8 vs. 0.73, 0.52-1.11: P < 0.05), whereas it was in the control range in AGCH and HDU patients (0.77, range 0.20-1.39 and 0.99, range 0.42-1.51; respectively). The count of fundic D cells was significantly lower in AGCH patients than in all other investigated groups (median 0.16, range 0.1-0.52; P < 0.05). Cure of infection in AGCH and HDU patients did not modify the ECL cell volume density, whereas a significant increase in the count of fundic D cells was observed in AGCH patients. Thus, the ECL/D cell index was significantly affected in AGCH patients (P < 0.05), being higher during H. pylori infection (median 6, range 0.7-9.25) than after the cure (median 2.12, range 1.10-3.5). BAO and PAO were not affected by H. pylori eradication in either group.

CONCLUSIONS

The study provides evidence, for the first time, that quantitative alterations in the fundic endocrine cells are not involved in acid hypersecretion of patients with hypersecretory states, and that eradication of H. pylori does not restore normal acid secretion values.

Hypergastrinemia and enterochromaffin-like cell hyperplasia

The enterochromaffin-like (ECL) cells, the most frequent endocrine cells of the oxyntic mucosa of the stomach, are under the trophic stimulus of gastrin. These cells undergo a hyperplastic increase in variety of hypergastrinemic diseases. The most widely accepted nomenclature for the description of hyperplastic proliferation has been retrospectively arranged in a sequence presumed to reflect a temporal evolution of the proliferative process. A comparative, prospective study aimed to verify, in human hypergastrinemic diseases such as atrophic body gastritis (ABG), Zollinger-Ellison syndrome (ZES) and antral gastrin cell hyperfunction (AGCH), the effect of exposure of ECL cells to different pattern of gastrin hypersecretion, is lacking. To this purpose, we studied a series of consecutive patients with ABG, ZES and AGCH at the time of first diagnosis.

MATERIAL AND METHODS

The patients included in this study (124 ABG, 18 ZES and 10 AGCH) were selected on the basis of two previously performed screening studies aimed to diagnose these diseases. All patients at the time of diagnosis underwent gastroscopy, with multiple biopsies of the gastric body mucosa for the evaluation of qualitative pattern of ECL cells hyperplasia, and basal fasting gastrin determination. A sample of hypergastrinemic patients from each group was further investigated by meal-stimulation of gastrin secretion and quantitative morphometry for CgA positive gastric body endocrine cells.

RESULTS

AGCH patients showed only the normal or simple hyperplasia pattern. In the ZES group, simple and linear grades accounted for 38.4 percent and 46.1 percent, respectively. MEN-I patients showed only these two patterns. The majority of ABG patients showed the presence of micronodular pattern (59.7 percent). A correlation analysis between fasting gastrin levels and grade of hyperplasia (r = 0.5580, p < 0.0001), indicates that the greater the gastrin levels, the higher is the degree of severity of ECL hyperplasia pattern. In conclusion, our data support the role of gastrin as the selective contributor to the progression of ECL cell hyperplasia in humans.

Atrophic body gastritis: distinct features associated with Helicobacter pylori infection

BACKGROUND

Usually, atrophic body gastritis has been considered an autoimmune disease characterized by the presence of parietal cell antibodies. Previous investigations into the role of Helicobacter pylori infection have obtained conflicting results. The aim of this study was to investigate the prevalence and role of H. pylori in a prospectively investigated population of patients with corpus-predominant atrophic gastritis.

PATIENTS AND METHODS

A consecutive series of 67 newly diagnosed cases of atrophic body gastritis was derived from a screening of 326 patients with unexplained anemia or dyspepsia. Criteria for diagnosis were fasting hypergastrinemia, pentagastrin-resistant achlorhydria, and histological confirmation of body atrophy. In all 67 patients, H. pylori infection was evaluated independently by histological assay and urease test. The gastritis status of both the fundic and antral mucosa were graded according to the Sydney system. Parietal cell and intrinsic factor antibodies also were determined.

RESULTS

Active H. pylori infection was present in 26.8% of our patients and allowed us to identify a patient's subpopulation with a significantly smaller degree of body mucosa damage as shown by functional parameters (gastrin, gastric acid secretion, pepsinogen I) and histological assessment. In this subpopulation, a higher prevalence of gastric cancer familial history was found. Presence of parietal cell antibodies showed a similar prevalence in H. pylori-positive and H. pylori-negative patients (61.1% vs. 69.4%) and was not associated with significant functional and histological differences. Cure of infection determined an evident improvement of corporal atrophy as well as a reduction of hypergastrinemia.

CONCLUSION

Active H. pylori infection, a potential cause of oxyntic gland atrophy, is found in one-fourth of patients with newly diagnosed atrophic body gastritis.

Eradication of Helicobacter pylori in patients with duodenal ulcer lowers basal and peak acid outputs to gastrin releasing peptide and pentagastrin

BACKGROUND

Patients with duodenal ulcer (DU) have high basal (BAO) and peak (PAO) acid outputs. The effect of Helicobacter pylori eradication on these variables is unclear.

AIM

To discover if gastric acid hypersecretion in patients with DU is caused by H pylori.

PATIENTS AND METHODS

BAO, gastrin releasing peptide (GRP), and pentagastrin stimulated PAO in 10 H pylori negative controls, and in 10 H pylori positive patients with DU was measured before and six months after H pylori eradication. H pylori status was determined by histology, culture, and by the 13C-urea breath test. After collecting a 30 minute basal aspirate, GRP 40 pmol/kg/h was infused for 45 minutes, and after a 30 minute washout, pentagastrin 6 micrograms/kg was injected intramuscularly.

RESULTS

Basal and stimulated acid output (PAOGRP and PAOPg) were significantly higher in H pylori positive DU than in H pylori negative controls. Six months after H pylori eradication, basal and stimulated acid outputs were all significantly lower than before H pylori eradication.

CONCLUSIONS

This study has shown that BAO, PAOGRP, and PAOPg are higher in H pylori positive DU than in H pylori negative controls. All decreased significantly six months after H pylori eradication, to fall within the range of controls. These results are compatible with a hypothesis that acid hypersecretion in duodenal ulcer disease is caused by H pylori infection.

Three months of octreotide treatment decreases gastric acid secretion and argyrophil cell density in patients with Zollinger-Ellison syndrome and antral G-cell hyperfunction

METHODS

The effects of three months of treatment with octreotide on gastric acid hypersecretion induced by hypergastrinaemia were investigated in patients with Zollinger-Ellison syndrome (n = 5) or antral G-cell hyperfunction (n = 4). Gastric acid secretion, fasting plasma gastrin concentrations and clinical findings were examined, and a morphometrical analysis of oxyntic endocrine cells was performed.

RESULTS

Administration of octreotide 100 mcg b.d. subcutaneously significantly decreased the volume density of argyrophil cells (P < 0.05) as well as basal and pentagastrin-stimulated acid secretion (P < 0.05). Although partial or complete loss of inhibition was found in most patients after 3 months, gastrin levels were decreased during the first 2 months of treatment (P < 0.05). Fundic D-cells were not affected by treatment. Positive correlations were observed between volume density of argyrophil cells and basal acid output (r = 0.65); plasma gastrin and basal acid output (r = 0.74); plasma gastrin concentrations and volume density of argyrophil cells (r = 0.80).

CONCLUSION

These results support the important role of the enterochromaffin-like cell in maintaining acid secretion, and indicate a specific role for octreotide in the therapy of gastric acid hypersecretion associated with hypergastrinaemic diseases.

Zollinger-Ellison syndrome and antral G-cell hyperfunction in patients with resistant duodenal ulcer disease

We measured basal and pentagastrin-stimulated acid secretion, as well as basal and meal-stimulated plasma gastrin concentration to determine, in 67 patients affected by resistant duodenal ulcer, whether their condition could be related to gastric acid secretion and/or gastrin-related syndromes. We then compared them to 46 duodenal ulcer control patients. The outpatients were investigated consecutively. The resistant duodenal ulcer patients differed from the controls only in their higher complication rates (bleeding or perforation, P < 0.05). We identified five patients in the resistant duodenal ulcer group with Zollinger-Ellison syndrome and 12 with antral G cell hyperfunction, whereas in the control group only one patient was affected by antral G cell hyperfunction. IgG anti-Helicobacter pylori antibodies were positive for the presence of infection in 7 of the hypergastrinaemic patients. When Zollinger-Ellison syndrome or antral G cell hyperfunction were excluded, no differences could be found in gastric acid secretion, or basal and meal-stimulated plasma gastrin levels, between the resistant and control duodenal ulcer patients, except for basal acid hypersecretion (resistant duodenal ulcer 16% vs duodenal ulcer 2% P = 0.0144). In the presence of duodenal ulcer disease resistant to H2-blockers, it is mandatory to measure basal plasma gastrin concentration since it was possible to diagnose the gastrin-related syndromes, Zollinger-Ellison syndrome and antral G cell hyperfunction, in 26% of this group of patients.

Morphometry of gastric endocrine cells in hypergastrinemic patients treated with the somatostatin analogue octreotide

The aim of the study was to evaluate whether treatment with 200 micrograms/d of the somatostatin analogue octreotide (SMS 201-995) for three months can influence the trophic action exerted by hypergastrinemia on endocrine cells of the oxyntic mucosa, a condition potentially leading to hyperplasia and carcinoid tumors. Endocrine cells were morphometrically investigated in Grimelius silver stained sections of endoscopic biopsies of oxyntic mucosa collected from 13 hypergastrinemic patients with Zollinger-Ellison syndrome (ZES) (n = 5), antral G cell hyperfunction (AGCH) (n = 4) and atrophic gastritis type A (AG-A) (n = 4) before and after 3 months treatment and 3 months after drug discontinuance. The treatment induced a reduction of the volume density (P < 0.015), profile cross sectional area (P < 0.05) and number of cell profiles per unit area (P < 0.015) of argyrophil cells. A rebound of all these parameters was observed 3 months after drug withdrawal with values usually exceeding those at the entry, except in cases of AG-A. The patients' plasma gastrin concentrations presented similar variations showing a significant relation with all morphometric parameters of argyrophil cells. Also, the cell content in alpha subunit of human chorionic gonadotropin was related to the plasma gastrin levels, a finding confirming the close gastrin dependence of the expression of this protein by oxyntic endocrine cells. No significant changes were observed in mucosal somatostatin D cells. These results indicate that variations in circulating gastrin levels are the most likely factor responsible for the hypotrophic effect of octreotide on oxyntic argyrophil cells (mostly corresponding to the ECL cells) of hypergastrinemic patients.

Omeprazole versus famotidine in the short-term treatment of duodenal ulcer disease

The efficacy and safety of omeprazole, in 241 patients with active recurrent duodenal ulcer from 21 Italian centres, was studied in a multicentre double-blind randomized trial comparing 20 mg omeprazole o.m. or 40 mg famotidine nocte with endoscopic examination, symptom recording, laboratory screening and gastrin assay. In a per protocol analysis, the duodenal ulcer healing rates for omeprazole and famotidine, documented by endoscopy, were 62% (68/109) and 33% (39/117) after 2 weeks of treatment (P less than 0.001), 92% (96/104) and 80% (86/108) cumulative after 4 weeks (P less than 0.05), and 99% (102/103) and 92% (96/104) after 6 weeks (P less than 0.05), respectively. The results of this trial demonstrate that 20 mg omeprazole o.m. is superior to 40 mg famotidine nocte in duodenal ulcer healing.

Antral gastrin cell hyperfunction in children. A functional and immunocytochemical report

Antral gastrin cell hyperfunction is a rare condition, often associated with severe duodenal ulcer disease. In children, clinical and functional characteristics of this syndrome are poorly known. Two cases are described here: one child had melena and the other had moderate abdominal pain, both without peptic ulceration. Basal and postprandial increase of gastrin levels showed a response over the upper normal range, indicating gastrin cell hyperfunction. Acid hypersecretion, both basal and after pentagastrin stimulation, was also found in the two children, confirming the biological effect of their sustained hypergastrinemia. Gastrin cell counts were within the normal range, while the number of somatostatin D cells was significantly reduced. This report stresses the importance of diagnosing antral gastrin cell hyperfunction in children because this unrecognized condition may manifest with serious complications (bleeding) or nonspecific abdominal symptoms.

Quantitative ultrastructure of endocrine cells of oxyntic mucosa in Zollinger-Ellison syndrome. Correspondence with light microscopic findings

The endocrine cells of the oxyntic mucosa of five patients with longstanding Zollinger-Ellison syndrome were quantitatively investigated with electron microscopy and two light microscopic methods (Grimelius and immunostaining for chromogranin A). Ultrastructurally, the volume density of endocrine cells was 3.2% +/- 1.1% of the mucosal epithelial component, a 168% increase (P less than 0.001) over the value found in normal subjects. Of the six endocrine cell types of human oxyntic mucosa, only enterochromaffinlike cells increased in cell density (65% +/- 15% of the total endocrine cell mass), size, and number of cell profiles per unit area. The enterochromaffinlike cells also underwent morphological changes of secretory granules with a decrease in vacuolated forms, increase in elongated profiles, and appearance of granules with a punctate structure of the core. The latter variety of granules was previously observed only in carcinoid tumors of the oxyntic mucosa and is possibly related to the enterochromaffinlike cell hyperplasia-neoplasia sequence seen in hypergastrinemic patients. A positive relationship was found between endocrine cell densities evaluated ultrastructurally and with chromogranin A immunostaining. It is concluded that in Zollinger-Ellison syndrome, the trophic effects induced by longstanding hypergastrinemia are strictly selective for enterochromaffinlike cells and are associated with ultrastructural features typical for enterochromaffinlike cell tumors.

Effects of high in vivo levels of vasoactive intestinal polypeptide on function of circulating lymphocytes in humans

To examine the possible in vivo significance of the immunomodulatory effects of vasoactive intestinal polypeptide described in vitro, several parameters of peripheral blood lymphocyte function were studied in a patient with a pancreatic endocrine tumor and high circulating levels of vasoactive intestinal polypeptide. There was no imbalance of the circulating lymphocyte subpopulations, and the in vitro responses of the patient's lymphocytes to mitogens were normal. However, there was an increased number (32%) of peripheral lymphocytes expressing interleukin 2 receptor. Serum immunoglobulin M levels were higher than in controls, and the patient's lymphocytes exhibited a spontaneous in vitro immunoglobulin M production higher than normal. Comparable increases in both interleukin 2 receptor expression and immunoglobulin M production were induced in vitro in normal peripheral lymphocyte cultures by the addition of vasoactive intestinal polypeptide concentrations similar to that detected in the patient's plasma. These findings indicate that a modulatory effect of vasoactive intestinal polypeptide on lymphocyte activation and immunoglobulin synthesis may be operating in vivo. They also suggest that vasoactive intestinal polypeptide does not mediate major defects in peripheral blood lymphocyte function in vivo.

Divergent effects of bombesin and bethanechol on stimulated gastric secretion in duodenal ulcer and in normal men

To further investigate differences in the responses of normals and patients with duodenal ulcer with respect to gastrin release and acid and pepsin secretion, we infused bombesin (1 microgram/kg X h) or bethanechol (40 micrograms/kg X h) during the middle hour of a 3-h infusion of pentagastrin and compared the results with a pentagastrin infusion without added drug. Pentagastrin dosage (0.1 microgram/kg X h) was set to give about half-maximal response, to detect either inhibition or further stimulation of gastric secretion, whereas the dose of bombesin was chosen to give maximal gastrin but less than maximal acid secretion. Serum gastrin and somatostatin were also measured. In all subjects tested, bethanechol produced no effects on acid, gastrin, or somatostatin release but increased pepsin output. By contrast, bombesin inhibited pentagastrin-stimulated acid output in all 6 normal men by an average of 55%, whereas it inhibited acid output in only 2 of the 9 men with duodenal ulcer. Serum gastrin increases after bombesin in duodenal ulcer were three to four times greater than in normals. Although bombesin stimulates acid only by releasing gastrin, we postulate that bombesin may also simultaneously limit acid and pepsin secretion and speculate that this effect could be mediated by bombesin-induced somatostatin release. The cause for differences between duodenal ulcer and normal remain speculative.

Evidence that bombesin releases extragastric gastrin in man

Bombesin-induced gastrin release from extragastric sources has been investigated in two groups of patients without gastric antrum: 11 patients with total gastrectomy and 11 patients with subtotal (Billroth II) gastrectomy. A 30-min bombesin infusion (5 ng . kg-1 . min-1) caused a prompt significant gastrin increase (P less than 0.05) in both groups of patients. The gastrin response to bombesin was significantly (P less than 0.005) lower in patients without antral tissue than in the control group (n = 7). The individual peak gastrin responses, in totally (TG) and subtotally (SG) gastrectomized patients, were significantly over basal levels (TG: peak 100.3 +/- 12 vs. basal 62.8 +/- 9.1, P less than 0.005; SG: peak 96.9 +/- 9.4 vs. basal 72.4 +/- 6.8, P less than 0.001; pg/ml, mean +/- S.E.M.). These data indicate that bombesin acts not only on antral G cells, but on all gastrin cells in the gastrointestinal tract.

Bombesin effects on human GI functions

In this article some of the actions of amphibian skin peptide Bombesin (BBS) on human gastrointestinal and pancreatic functions are reviewed. BBS causes increases of lower esophageal sphincter pressure, delay of gastric emptying, inhibition of mechanical activity of duodenum and jejunum and gallbladder emptying. BBS also releases in man gastrin and stimulates gastric acid secretion. BBS administration induces release of insulin, glucagon and pancreatic polypeptide from human Islet of Langerhans and causes secretion of pancreatic bicarbonates and enzymes in duodenal juice and release of pancreatic enzymes in blood stream.

Innervation of the muscularis mucosae of canine proximal colon

The innervation of the muscularis mucosae of the canine large intestine was studied in vitro using superfusion and radioimmunological techniques. In the majority of preparations, electrical field stimulation (10 V, 200 microseconds, 10 Hz) elicited a biphasic neurogenic response which consisted of a contraction followed, after cessation of the stimulus, by relaxation. Electrical field stimulation released VIP-, substance P- and bombesin-like immunoreactivity. Release of these peptides and the biphasic response to nerve stimulation were blocked by tetrodotoxin and a 'calcium-free' solution. Several observations suggest that neuronally released substance P (or a closely related peptide) mediated the contraction by a direct action on the muscle. The contraction caused by substance P was tetrodotoxin insensitive. Desensitization to substance P abolished the excitatory response to nerve stimulation. The contraction elicited by nerve stimulation was blocked by substance P antiserum. Several observations suggest that bombesin or a closely related peptide caused contraction of the muscle by releasing substance P from intramural neurones. Bombesin caused an increase in substance P-like immunoreactivity in the superfusate which was blocked by tetrodotoxin, as was the contraction; substance P antibodies blocked the contractile response to bombesin. In addition, while the excitatory response to electrical nerve stimulation was blocked by substance P antiserum, there was still an increase in bombesin-like immunoreactivity in the superfusate. The data also suggest that VIP or a closely related peptide might have mediated the relaxation by a direct action on the muscle. The inhibitory response to nerve stimulation was mimicked by VIP and abolished by VIP antiserum.