Alterations in secretory patterns following antrectomy in rats with Pavlov pouches.
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1. In conscious rats provided with Pavlov pouches, with the antrum retained or resected,the gastric secretory response to various stimuli has been studied. Each acid secretory response was related to that obtained with maximal doses of methacholine and histamine in combination, presumed to reflect the maximal secretory capacity of the mucosa. 2. Three weeks after the operation, the maximal acid secretory capacity was 60 percent lower in the antrectomized than in the intact Pavlov pouch rats; the difference was still larger at 6 weeks and 3-5 months, owing to a gradual increase in the rats with the antrum retained. 3. Antrectomy reduced interdigestive secretion of acid to the same degree as the concomitant reduction in maximal secretory capacity. 4. Acid secretion in response to a maximal infusion of pentagastrin was reduced by about 50 percent at 3 and about 65 percent at 6 weeks after antrectomy. No significant difference was, however, noted between the antrectomized and intact rats when the responses were related to the maximal secretory capacity. The dose response curve to pentagastrin revealed a redcued responsiveness to submaximal doses of this agent following antrectomy. 5. The maximal acid secretory response to histamine was reduced after antrectomy, although the sensitivity to submaximal infusions of histamine appeared to be increased. 6. The mean secretroy output to 2-deoxy-D-glucose was reduced by about 65 percent and that to food by about 85 percent following antrectomy. 7. After antrectomy a background infusion of pentagastrin enhanced the secretory responses to 2-deoxy-D-glucose and to food but did not restore the responses to the levels in the intact rats. The feeding responses as related to the maximal secretory capacity were, however, similar in the two groups on infusing pentagastrin in the antrectomized rats. 8. Interdigestive secretion of pepsin was reduced by about 60 percent after antrectomy, while the peak response to 2-deoxy-Dglucose was about twice the interdigestive level in both groups. Pepsin secretion in response to food showed an increased secretion above the interdigestive level of longer duration in the antrectomized than in the intact Pavlov pouch rats. 9. The irreversibily reduced responsiveness of the gastric mucosa after antrectomy is discussed in relation to known morphological and biochemical changes. (+info)
Differences in surface-exposed antigen expression between Helicobacter pylori strains isolated from duodenal ulcer patients and from asymptomatic subjects.
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We have analyzed possible qualitative and quantitative differences in antigen expression between Helicobacter pylori strains isolated from the antrum and different locations in the duodenum of 21 duodenal ulcer (DU) patients and 20 asymptomatic subjects (AS) by enzyme-linked immunosorbent assay (ELISA) and inhibition ELISA. Almost all antral and duodenal strains grown in vitro expressed the N-acetyl-neuroaminyllactose-binding hemagglutinin, flagellins (subunits FlaA and FlaB), urease, a 26-kDa protein, and a neutrophil-activating protein. In 75% of both the DU patients and the AS, antral H. pylori strains expressed either the blood group antigen Lewis y (Le(y)) alone or together with the Le(x) antigen. However, duodenal H. pylori strains of DU patients expressed Le(y) antigen more frequently than corresponding strains of AS (P < 0.05). Presence of Le(y) on H. pylori was related to the degree of active duodenitis (P < 0.05). Duodenal H. pylori strains isolated from AS were significantly more often Lewis nontypeable than duodenal strains of DU patients (P < 0.01). Presence of H. pylori blood group antigen-binding adhesin (BabA) was significantly higher on both antral and duodenal strains isolated from DU patients than on corresponding strains isolated from AS (P < 0.05). BabA-positive duodenal H. pylori strains isolated from DU patients were associated with active duodenitis more frequently than corresponding strains isolated from AS (P < 0.01). Infection with H. pylori strains positive for Le(y) and BabA in the duodenum is associated with development of duodenal ulcer formation. (+info)
Anti-CagA immunoglobulin G responses correlate with interleukin-8 induction in human gastric mucosal biopsy culture.
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Helicobacter pylori persists in the human stomach despite eliciting both cellular and humoral immune responses and inducing proinflammatory cytokines. To determine whether local humoral and cytokine responses are related to each other and to histologic responses, we studied 66 Japanese patients who underwent gastroscopy. Using specific enzyme-linked immunosorbent assays, we examined gastric antral mucosal-organ biopsy culture supernatants to assess interleukin-6 (IL-6) and interleukin-8 (IL-8) levels and antibody responses to H. pylori whole-cell antigens CagA, HspA, and HspB. Of the patients studied, 11 were H. pylori negative and 55 were H. pylori positive; by PCR, all strains were cagA(+). As expected, compared to H. pylori-negative patients, H. pylori-positive patients had significantly higher humoral responses to all H. pylori antigens and had higher IL-8 (47.8+/-3.5 versus 10.1+/-4.3 ng/mg of biopsy protein; P<0.001) and IL-6 levels (2.8+/-0.3 versus 0.26+/-0.2 ng/mg of protein; P<0.001). Among the H. pylori-positive patients, supernatant anti-CagA immunoglobulin G (IgG) levels were significantly associated with H. pylori density (P<0.005) and neutrophil infiltration (P<0.005) scores. Anti-CagA immunoglobulin A levels were correlated with intestinal metaplasia (P<0.05). Mononuclear cell infiltration scores were significantly associated with supernatant IL-6 levels (P<0.005) and with IgG responses to whole-cell antigens (P<0.05). Supernatant IL-8 levels were significantly associated with anti-CagA IgG (r = 0.75, P<0.001). Anti-CagA responses correlated with neutrophil infiltration, intestinal metaplasia, H. pylori density, and IL-8 levels, suggesting that the absolute levels of these antibodies may be markers for gastric inflammation and premalignant changes in individual hosts. (+info)
Gastric, antral and fundic pouch secretion in sheep.
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1. Fundic secretion of HCl and pepsin was studied in sheep with both fundic and antral pouches. The antral pouches were of the entire pyloric region. Continuity of the alimentary tract was restored by an abomasoduodenal anastomosis. 2. Secretion from fundic pouches was continuous. It was reduced in volume and acidity, was pepsin output, by resection of the antral pouches. 3. Teasing with food, feeding and injection of pentagastrin stimulated fundic acid and pepsin secretion in animals with antral pouches before and after antrectomy. 4. Pouches prepared from the entire pyloric region showed continuous secretion with variations not related to feeding or fasting. Antral secretion was increased after s.c. injections of histamine, carbachol and pentagastrin. 5. It is concluded that although the pyloric antrum contributes to the magnitude of the secretory response of an abomasal fundic pouch, the direction of the secretory response is similar whether or not the pyloric antrum is present as a separated pouch, or is removed. (+info)
[Na+]i, [K+]i and [Cl-]i regulation of exocytosis in guinea-pig antral mucous cells.
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Effects of intracellular Na+, K+ and Cl- on Ca(2+)-regulated exocytosis activated by 10 microM acetylcholine (ACh) were studied in guinea-pig antral mucous cells which are permeabilized by nystatin treatment. Ca(2+)-regulated exocytotic events were modulated by [Na+]i, [K+]i and [Cl-]i via mediation of PTX-sensitive G proteins. Increases in [Na+]i and PTX inhibit G protein (G(Na)), which suppressed the exocytosis. Increases in [K+]i caused the exchange of G proteins (from G(Na) to G(K)) to increase, and GK evoked activation of the exocytosis and was inhibited by PTX. Increases in [Cl-]i and PTX inhibit G protein (G(Cl)), which stimulates exocytotic events. Based on these observations, the exocytosis in antral mucous cells were modulated by intracellular ions, concentration of which were increased or decreased by cell volume changes caused by Ach. (+info)
Comparison of anterior and geometric mean liquid and solid gastric emptying rates in dogs and in patients after partial gastrectomy.
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OBJECTIVE: The purpose of this study was to determine if geometrical correction is necessary in the study of gastric emptying rate (GER) for liquids, using a low-energy radionuclide, such as 99mTc. Solid test meals were considered the reference. METHODS: Both solid and liquid GERs were investigated using regional analysis. Anterior data were compared with geometrically corrected values in 15 dogs and 9 partial gastrectomy patients. RESULTS: Anterior and geometrically corrected measurements differed significantly for solid food in the whole gastric region and in the antrum. Geometrically corrected values differed slightly from anterior data after partial gastrectomy. No difference was found for liquid food. Liquids redistributed much faster than solids within the stomach. CONCLUSION: Measurement of GER using a single-phase liquid meal does not require geometrical correction. This is due to the rapid intragastric redistribution of the liquid. Geometrical correction for solid food can be omitted only after partial gastrectomy. (+info)
How do fiber-supplemented formulas affect antroduodenal motility during enteral nutrition? A comparative study between mixed and insoluble fibers.
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BACKGROUND: Fiber supplementation during enteral nutrition has been recommended, but the effect of soluble compared with insoluble fiber supplements on antroduodenal motility is unknown. OBJECTIVE: The objective of this study was to compare antroduodenal motor patterns in 8 healthy volunteers during and after gastric infusion of 3 different diets: a fiber-free diet, an insoluble-fiber diet, and a mixed-fiber diet (50% soluble fiber and 50% insoluble fiber). DESIGN: Manometric studies with the 3 different diets (2100 kJ) were performed in random order. Antroduodenal motility was monitored continuously for 6 h by using a pneumohydraulic system to calculate the number, amplitude, and duration of the pressure waves; the area under the curve (AUC); and the percentage of time occupied by motor activity before, during, and after each type of infusion. Variations in antral areas were measured by ultrasonography. RESULTS: The gastric motor response was significantly higher, whatever the diet, in the distal antral recording site than in the 2 more proximal sites. In the proximal but not the distal antrum, the number of waves, the AUC, and the percentage of time occupied by motor activity were higher (P: < 0.04) with the mixed-fiber than with the insoluble-fiber diet. No significant differences in variations of antral area were observed among the 3 diets. In the duodenum, motor variables were not significantly different among the 3 diets. CONCLUSIONS: A gastric infusion induced a greater motor response in the distal than in the proximal antrum. A mixed-fiber diet was associated with significantly greater proximal antral motility than was an insoluble-fiber diet. There was no significant difference among the 3 formulas in duodenal motor variables or in variations in antral area as measured by ultrasound. (+info)
Changes in Helicobacter pylori-induced gastritis in the antrum and corpus during long-term acid-suppressive treatment in Japan.
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BACKGROUND: Several studies have shown that acid-suppressive therapy aggravates corpus gastritis in patients with Helicobacter pylori infection, promoting the development of atrophic gastritis. AIM: To study the effects of long-term use of antisecretory agents on the H. pylori-positive gastric mucosa in Japan, a country with a high incidence of gastric cancer. METHODS: A total of 141 H. pylori-positive patients who had peptic ulcers or reflux oesophagitis were treated for 3 years with either omeprazole (20 mg/day) alone (n=7) or with omeprazole for primary therapy (8 weeks), followed by famotidine (40 mg/day) for maintenance therapy (n=134). Endoscopy was performed before, during, and after treatment. Biopsy specimens were taken from the greater curvature of the antrum and corpus and were examined histologically. RESULTS: The long-term use of famotidine after 8 weeks of treatment with omeprazole distinctly decreased H. pylori density and neutrophil infiltration in the antrum, but did not change H. pylori density in the corpus. The gastritis score increased in patients who had no, or only mild corpus gastritis before treatment (n=74), and significantly decreased in those who had moderate or severe gastritis before treatment (n=60). In four of the seven patients who received long-term treatment with omeprazole alone, neutrophil infiltration and H. pylori density decreased not only in the antrum but also in the corpus. There was no increase in intestinal metaplasia or mucosal atrophy as assessed endoscopically during follow-up. CONCLUSION: Changes in corpus gastritis in response to acid-suppressive therapy depend on the severity of gastritis before treatment. Long-term use of acid-suppressive therapy apparently does not accelerate the development of atrophy or intestinal metaplasia in Japanese patients. (+info)