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At least 469 records · Page 26Linked to original sources

Quantitative measurement of mRNA coding for the receptors controlling acid secretion in the ovine fundus and antrum by using RT-PCR.

BACKGROUND AND AIMS: Gastric acid secretion is stimulated by the action of gastrin, histamine and acetylcholine on their respective receptors. To determine the regulation of synthesis of these receptors during different gastric secretory states a competitive RT-PCR method for quantitating the mRNA for these receptors was developed. METHODS: Partial cDNA clones (400-500 base pairs (bp)) for the ovine gastrin, histamine (H2) and acetylcholine (M3) receptors were isolated and sequenced. These cDNA constructs were modified by the inclusion of approximately 100 bp of unrelated sequence within the plasmids. cDNA was synthesized from a mixture of known amounts of RNA transcribed from the modified plasmids and from total RNA extracted from sheep stomach. Proportional coamplification of mixed cDNA was demonstrated using common primer sets. RESULTS: All three receptors were more highly expressed in the fundus than the antrum. The concentration of cholecystokinin-B/gastrin receptor mRNA was 75-fold higher in the fundus than in the antrum, and the concentration of both histamine and acetylcholine receptor mRNA were fivefold higher in the fundus than in the antrum. Infusion of gastrin caused a significant increase in fundic histamine mRNA receptor expression, but not in the expression of the gastrin or muscarinic receptors. CONCLUSIONS: No significant differences were observed in the levels of receptor mRNA between normal adult and fetal animals despite markedly reduced gastric secretion in the fetus, suggesting that gastric receptor gene expression is not the rate-limiting factor in determining gastric acid secretion in the neonatal animal.

Aging↗

[A rapid radionuclide method for clinical assessment of gastric juice proteolytic activity and acidity].

A new method for radionuclide measurement of gastric juice proteolytic activity (GJPA) is described. GJPA is determined according to the time of dissolution of the protein capsule filled with 99mTc-pertechnetate solution. In vitro experiments made with 342 samples of gastric juice revealed a correlation (p1 less than 0.01) between the time of dissolution of the 99mTc-pertechnetate capsule and proteolytic activity measured according to Metta's method. No correlation was established between GJPA (measured by Metta's method and by radionuclide method) and gastric juice acidity (p greater than 0.05). In 63 patients examined, the time of capsule dissolution was 15 to 18 minutes with GJPA being normal, 8 to 14 minutes (p less than 0.01) with elevated parameters of GJPA, and 19 to 37 minutes (p less than 0.01) with GJPA being reduced. The given method is a physiological one, sufficiently precise and can be recommended for a screening analysis of GJPA.

Adolescent↗

[Effect of a new opioid peptide on gastric secretion in the rat stimulated with 2-deoxyglucose].

Gastric secretion was studied in conscious rats with chronic gastric fistulae maintained in restraint cages. Experiments were performed 24 hours after surgical procedure: the stomachs were washed with 3 ml of saline and gastric acid determined by titration of pH 6 every 30 minutes. The i.v. injection of 75 mg/kg of 2DG strongly stimulated gastric secretion, with a 5-fold increase of acid output in comparison to control rats. The slow intravenous injection of dermorphin, 15 min before 2DG, dose-dependently inhibited the stimulant effect of the latter. Opioid activity of dermorphin has been reported (5); on the other hand, the intracerebroventricular injection of opiates has been shown to decrease the gastric secretion of the rat by Rozé et al. (3). The effectiveness of dermorphin given by intravenous route observed in present experiments seems to suggest the hypothesis that dermorphin (and other opiates) may act, besides central, also on peripheral sites.

Animals↗

Low intramucosal pH is associated with failure to acidify the gastric lumen in response to pentagastrin.

OBJECTIVE: To determine if low gastric intramucosal pH is associated with impaired secretion of gastric acid after pentagastrin stimulation. DESIGN: Prospective study. SETTING: Intensive care unit of a university teaching hospital. PATIENTS: 20 patients requiring mechanical ventilation. INTERVENTIONS: All patients with a gastric luminal pH > 4 were given pentagastrin 6 micrograms/kg s.c. to stimulate gastric acid secretion and the response assessed by further measurements of gastric luminal pH. MEASUREMENTS AND RESULTS: Gastric intramucosal pH (pHi) and luminal pH (pHL) were measured. Patients were divided into two groups on the basis of a low or normal pHi (A value of 7.35 was taken as the lower limit of normal). Patients (n = 6) with normal pHi (7.40 +/- 0.05 [mean +/- SD]) and a luminal pH > 4 (5.65 +/- 1.25) all had a decrease in pHL in response to pentagastrin (decrease in pHL 4.02 +/- 1.52). Of the patients (n = 7) with low pHi (7.2 +/- 0.13) and a pHL > 4 (6.51 +/- 0.48) only one responded to pentagastrin (decrease in pHL for this group 0.93 +/- 1.86). Patients with a pHL < 4 (2.4 +/- 0.71) were not given pentagastrin (n = 7). CONCLUSION: Some critically ill patients with low gastric intramucosal pH appear to have an impaired ability to acidify the gastric lumen in response to pentagastrin.

Achlorhydria↗

Effects of nocloprost on gastric functions in man.

Previous studies in animals and humans demonstrated that nocloprost, a stable prostaglandin E2 analogue, shows very high gastroprotective potency, relatively weak gastric inhibitory activity, and low systemic bioavailability after oral administration. In this study the effects of nocloprost on gastric acid secretion and intraluminal pH and on gastric emptying and plasma gastrin levels were determined in humans. Nocloprost at doses of 50 and 100 micrograms was ineffective, but at a dose of 200 micrograms it reduced the response to pentagastrin significantly and that to a peptone meal by 30-50% and abolished plasma gastrin response without affecting the rate of gastric emptying. Nocloprost given at a dose of 100 micrograms three times daily 30 min before the major meals (breakfast, lunch, and dinner) did not affect intragastric pH significantly as monitored by continuous intraluminal pH-metry. We conclude that nocloprost does not affect gastric acid secretion or intraluminal pH when applied at a dose (50-100 micrograms) that is gastroprotective and that is proposed for peptic ulcer therapy. A higher dose (200 micrograms) of nocloprost causes moderate gastric acid inhibition and suppression of plasma gastrin release without affecting gastric emptying or causing any side effects.

Adult↗

[Effect of cimetidine on maximal stomach secretion in physical stress and at rest in patients with chronic duodenal ulcer].

In 21 males suffering from chronic duodenal ulcers the effect of cimetidine on the maximum acid output (MAO) both in rest and under physical load was examined. Patients were loaded two times (60 min) with the Monark bicycle ergometer at an interval of 5-7 days. Immediately before second examination cimetidine was injected intravenously (6 mg/kg body weight). The sampling of gastric juice was done 3 times for 60 min before, during and after the physical work. In the stimulated gastric fluid the concentrations of sodium, potassium, chlorid ions, total protein and mucoproteins were checked. In the peripheral venous blood sodium, potassium, chlorid, magnesium and calcium were measured as well as glucose and the parameters of acid base state. Cimetidine significantly reduced ionic concentration, protein and mucoproteid concentrations of the gastric fluid. Cimetidine did not provoke any changes of the parameters determined in the peripheral blood.

Adult↗

The protective effect of copper complexes against gastric mucosal ulcer in rats.

The study examines the anti-ulcer activity of Cu(I)-(nicotinic acid)2Cl [CuCl(HNA)2]. A dose of 8 mg (23 mumol) of complex/kg body mass was suspended in 0.25% Tween-80 in saline solution and administered intragastrically to male Wistar albino rats which had developed gastric ulcers as a result of pyloric ligation (Shay-rat model). Another group of animals received 5 mg (25 mumol)/kg body mass of the copper-glycinate complex Cu(II)(glycinate)2 [Cu(II)(Gly)2]. Both protected as shown by reduction in the ulcer index, inhibition of gastric perforation and death. Significant increases in gastric juice volume and superoxide dismutase (SOD) activity in the gastric mucosa and blood plasma were found with both copper complexes, while the gastric juice prostaglandin E2 (PGE2) content was significantly decreased in the Cu(II)(Gly)2-treated group, it was significantly increased in the gastric mucosa of the CuCl(HNA)2-treated group. The copper complex-treated animals, especially those which received Cu(II)(Gly)2 had a marked fall in thromboxane A2 (TXA2) levels. These results suggest that intragastric administration of either CuCl(HNA)2 or Cu(II)(Gly)2 produced anti-ulcerogenic activity, with different modes of action.

Animals↗