The intestinal phase of gastric secretion.
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The intestinal phase hormone, elaborated by the jejunum in response to an intestinal meal or simple distension, produces profound gastric hypersecretion when it escapes hepatic degradation through a portacaval anastomosis. The hormone is released within 30 min of the application of the stimulus and rapidly reaches peak concentration in the portal blood. Intravenous infusion into a donor dog of active portal plasma from a shunted, intestinally fed dog stimulates gastric acid secretion after a delay of approximately 1 h, and requires a mean 1 1/2 h to stimulate peak secretion, which suggests that intermediate steps may be necessary before the hormone can effectively stimulate the parietal cell mass. The pig develops portacaval-shunt-related gastric acid hypersecretion in response to food comparable to that observed in the dog and in man. Porcine jejunal mucosa is thus an appropriate source for isolation of the intestinal phase hormone. Pig intestinal mucosal extract contains a heat-stable acidic peptide which is a potent stimulator of gastric acid secretion. Administration of crude intestinal mucosal extract elicits gastric acid secretion after a brief delay, again indicating that some intermediate reactions occur before the target organ--the parietal cell mass--is stimulated. (+info)
Bile acid excretion after pull-through operation for Hirschsprung's disease.
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Four children with chronic diarrhoea and perianal excoriation after a pull-through operation for Hirschsprung's disease have been shown to have increased but not markedly raised levels of faecal bile acids. Bile acid analysis of the 'bile-rich' duodenal fluid obtained after pancreozymin stimulation in 3 of the patients indicated a marked reduction in the proportion of deoxycholic acid conjugates. These findings are compatible with colonic malabsorption of secondary bile acids in these patients which is related in some way to the pull-through operation, but which is not likely to be the cause of the diarrhoea and the anal excoriation. (+info)
The effect of sympathetic nerve stimulation on acid secretion, regional blood flows and oxygen usage by stomachs of anaesthetized cats.
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1. Gastric acid secretion, and total gastric and mucosal blood flows (amidopyrine technique) were measured in anaesthetized cats. Oxygen contents of arterial and gastric venous blood were measured using an oximeter. 2. Splanchnic nerve stimulation (10 Hz) significantly reduced the acid output and total gastric and mucosal blood flows produced in response to maximal gastrin pentapeptide infusions. 3. The arterial haemoglobin concentration was significantly reduced during splanchnic nerve stimulation, and this is consistent with the hypothesis that the splanchnic nerve effect is directed against precapillary sphincters. 4. During the period of inhibition, gastric oxygen consumption and acid secretion were reduced to similar degrees. There was no significant change in oxygen extraction by the stomach. 5. It remains possible that the splanchnic nerves directly inhibit the parietal cell activity. (+info)
Colonisation density and topographic localisation of Helicobacter pylori do not depend on the cagA status.
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AIMS: To explore the correlation between the cagA status of Helicobacter pylori and the density and topographic localisation of H pylori. METHODS: Gastric antral biopsy specimens were taken from 716 consecutive patients, including 293 H pylori positive patients (124 men, 169 women; mean age, 52.6 years; range, 12-87). A serum sample was taken for determination of IgG anti-CagA antibodies (sensitivity of 94.4% and specificity of 92.5%). The density of H pylori was assessed semiquantitatively (grades I-IV) in biopsy specimens stained with the modified Giemsa stain. Topographic localisation was classified as follows: score A, H pylori closely attached to the mucosa; score B, H pylori attached to the mucosa and in the mucus; and score C, H pylori solely in the mucus. RESULTS: CagA antibodies were present in 154 (52.5%) of the patients. There was no significant difference in colonisation density and cagA status: grade I, 23 (14%); grade II, 78 (50.6%); grade III, 42 (27.5%); and grade IV, 11 (7.2%) in the cagA(+) strains and 29 (21.2%), 57 (40.8%), 38 (27%), and 15 (11%), respectively, in the cagA(-) strains. There was no difference in topographic localisation between cagA(+) and cagA(-)H pylori. Mean anti-CagA titres were 0.84, 0.84, 0.89, and 0.73 in patients with grades I-IV bacterial density, respectively. CONCLUSION: Antibody titres do not correlate with H pylori density and there is no difference in density between cagA(+) and cagA(-)H pylori strains. In addition there is no difference in topographic localisation between cagA(+) and cagA(-) H pylori strains. (+info)
Protective effects of Ginkgo biloba extract on gastric mucosa.
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AIM: To study the protective effects of Ginkgo biloba extract (GbE) on gastric mucosa. METHODS: By means of restaint-cold stress (RCS) in rats and 100% ethanol gavage in mice, the index of gastric mucosal injury was evaluated. The gastric juice was collected using pyloric ligation, and the volume and acidity of juice, and activity of pepsin were determined. The content of malondialdehyde (MDA) was measured by thiobarbituric acid (TBA) method. RESULTS: GbE (25, 50, and 100 mg/kg, bid x 5 d, ig) inhibited dose-dependently the gastric mucosal injury induced by RCS and 100% ethanol gavage. The index of gastric mucosal injury after RCS in groups pretreated with GbE was 58%, 43%, and 31% of control group respectively. The index of gastric mucosal injury induced by ethanol in groups pretreated with GbE was 62%, 36%, and 26% of the control group, respectively. And GbE enhanced the protective effects of cimetidine (Cim) on gastric mucosa. But it did not obviously influence the volume and acidity of gastric juice as well as the activity of pepsin. One hour after the administration of ig 100% ethanol, the contents of MDA in gastric mucosa and serum in mice increased (P < 0.01) vs the control group. But pretreatment with GbE (25, 50, and 100 mg/kg, ig) could inhibit this increase of MDA both in gastric mucosa and in serum. CONCLUSION: GbE had protective effects on gastric mucosa and GbE plus Cim possessed the synergism in the treatment of acute gastric mucosal lesions. (+info)
Potency and selectivity of methyl analogues of prostaglandin E2 on rat gastrointestinal function.
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1 The potency and selectivity of action of prostaglandin E2 and its (15S)- or (15R)-15 methyl and 16, 16 dimethyl analogues on gastrointestinal function have been studied in the rat. 2 The (15S)-15 methyl and 16, 16 dimethyl analogues were 40 times as active as prostaglandin E2 in inhibiting pentagastrin-stimulated acid secretion on intravenous administration to the anaesthetized rat, and 100 times as active on subcutaneous injection to the chronic fistula rat. 3 In antisecretory doses, the analogues, like prostaglandin E2, caused bile reflux and, in higher doses, profuse diarrhoea. 4 The (15S)-15 methyl and 16, 16 dimethyl analogues were at least 30 times as active as prostaglandin E2 in causing changes in intestinal intraluminal pressure in vivo, but were equipotent on isolated smooth muscle. 5 In equivalent antisecretory doses, the methyl analogues had little effect on systemic arterial blood pressure and resting mucosal blood flow compared with prostaglandin E2. 6 The (15R) methyl epimer administered parenterally had little effect on gastrointestinal function but brief acid incubation greatly increased its activity. (+info)
Quantitative method for the gas chromatographic analysis of short-chain monocarboxylic and dicarboxylic acids in fermentation media.
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A method for the preparation and gas chromatographic analysis of the butyl esters of volatile (C-1-C-7) and nonvolatile (lactic, succinic, and fumaric) acids in microbial fermentation media is presented. Butyl esters were prepared from the dry salts of the acids. The esters were separated by temperature programming on a column of Chromosorb W coated with Dexsil 300 GC liquid phase and analyzed with a flame ionization detector. Apparent recoveries with butanol-HCl or butanol-H2SO4 as butylating agents were 80 to 90% for most acids. Chromatographic profiles of the butyl esters demonstrated that both volatile and nonvolatile acids can be detected and separated in 24 min on a single column. Standard calibration curves (peak area versus concentration) of the butyl esters were linear in the range of 5 to 40 mumol of acid per ml. The advantages of using an internal standard (heptanoic acid) for quantitating fatty acids in a mixture are given. Chromatograms of butylated fermentation media in which rumen anaerobic bacteria were grown illustrated that this method is useful for determining short-chain volatile and nonvolatile acids of toxonomic significance. (+info)
pH dependence of acid secretion and gastrin release in normal and ulcer subjects.
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By use of a recently described method, which estimates the rate of gastric acid secretion by measuring the rate of sodium bicarbonate infusion needed to keep intragastric pH constant, gastric acid secretion rates and changes in serum gastrin were measured in five normal subjects while gastric pH was kept at 5.5, 4.0, 3.0, or 2.5. Preliminary experiments revealed that the method did not accurately measure acid secretion at a pH lower than 2.5. Stimulation of acid secretion was produced by gastric instillation of a solution of amino acids and cornstarch. The secretion rate with the amino acid meal was highest at pH 5.5 and was 60% of that produced by a steak meal at the same pH. As the pH of the amino acid meal was decreased, there was a stepwise reduction in acid secretion so that at pH 2.5 the rate was only half as great as at pH 5.5. The amino acid meal produced increases in serum gastrin that were also less marked than those produced by a steak meal. With amino acid stimulation, serum gastrin responses were similar at pH 5.5, 4.0, and 3.0, but no increase in gastrin could be measured when the meal was maintained at pH 2.5. A group of six patients with duodenal ulcers was compared with seven normal subjects at pH 5.5 and 2.5. Ulcer patients released more gastrin and secreted more acid at each time period at both pH values. More important, the degree of inhibition at pH 2.5 was significantly less in ulcer patients. For example, during the 2nd h after stimulation acid secretion was inhibited by only 30% in ulcer patients compared with 70% in normal subjects. These findings suggest a defect in autoregulation of gastrin release and gastric acid secretion at low pH in ulcer patients which may play a role in pathogenesis of this disease. (+info)