Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0847097 (acidity)
 15,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pancreatic enzyme replacement may fail to achieve a beneficial effect because of enzyme inactivation by gastric acid. In this controlled randomized study, 8 hospitalized patients with severe exocrine pancreatic insufficiency and considerable steatorrhoea (greater than 15 g faecal fat/day) were treated with a conventional pancreatic enzyme preparation (Pankreon 700; 3 X 3 dragees daily), with (300 mg) and without cimetidine before meals, and with a new pH-sensitive enzyme preparation (Kreon; 3 X 6 capsules daily) comprising acid-protected granules. Both conventional enzyme replacement plus cimetidine, and acid-protected pancreatin were significantly (p less than 0.05) more effective than conventional enzyme therapy alone. Since both regimens are equally potent in overcoming gastric acid-induced enzyme inactivation, it is concluded that therapy with acid-protected pancreatin may simplify and improve treatment of exocrine pancreatic insufficiency in the presence of gastric hyper- or normo-acidity.
Z Gastroenterol 1986 Dec
PMID:Therapy of pancreatogenic steatorrhoea: does acid protection of pancreatic enzymes offer any advantage? 354 9

Intraluminal pH was measured simultaneously in the human stomach and proximal duodenum with six small glass electrodes tied together at 1.5-cm intervals. Twenty-four healthy control subjects and 44 patients with duodenal ulcer disease were studied under fasting conditions and for 3 h after a standard liquid meal. Mean and median hydrogen ion activity, percentage of time with pH below 2 and 3, and the frequency of pH fluctuations were calculated from digital pH data sampled at a frequency of once per second from each electrode. None of these measurements of acidity differed significantly between the two groups or between subgroups of normosecretor controls and hypersecretor ulcer patients. At the time of pH study 15 of the patients had endoscopically verified active ulcer disease and 13 patients were without disease activity. Gastric as well as duodenal bulb acidity was the same in these two subgroups. We conclude that even though duodenal ulcer patients deliver more acid into the duodenum, this does not cause increased luminal acid aggression.
Gastroenterology 1987 Dec
PMID:Duodenal bulb acidity in patients with duodenal ulcer. 367 44

Intravenous cimetidine, 300 mg or 400 mg, or ranitidine, 50 mg, was administered as a single dose to 36 volunteers in a randomized, crossover fashion. Aspirates of gastric juice were obtained after dosing, and the pH, titratable acidity, gastric fluid volume, and gastric acid output were determined from baseline through 71/2 hours for each subject. Each intervention significantly increased pH and suppressed hydrogen ion concentration, gastric fluid volume, and gastric acid output. Both the magnitudes of the changes when compared with baseline and the time of the mean maximum effects were similar in all three drug regimens. The effect of all three interventions on gastric fluid volume and gastric acid output diminished sharply after 6 hours. The data indicate that the gastric secretory response to all three interventions did not differ substantially.
Clin Pharmacol Ther 1986 Dec
PMID:The effect of single intravenous doses of cimetidine or ranitidine on gastric secretion. 378 Jan 28

The ionic compensatory response to CO2 breathing for 3 days was studied on intact and cystectomized turtles at 10 and 20 degrees C. Arterial blood gases, pH, ionized calcium, and the plasma concentrations of Na+, K+, Cl-, total Ca2+, and total Mg2+ were measured periodically. At 20 degrees C, ureteral urine was also collected from bladderless turtles and was analyzed for pH, ions, NH3+, total CO2, osmolality, and titratable acid. When CO2 was breathed there was a compensatory change in the strong-ion difference as manifest by an increase in plasma [HCO3-] that was approximately 10 meq/l both in the 10 and 20 degrees C turtles. The only significant associated strong-ion changes observed consistent with the ionic compensatory response were increases in total and ionized Ca2+ and total Mg2+. These results were unaffected at either temperature by surgical removal of the urinary bladder. Urine collected from cystectomized turtles showed no compensatory increase in acid excretion during hypercapnia; in fact, changes occurred in the opposite direction. Urinary excretion of HCO3- and urine pH increased significantly, whereas titratable acidity decreased significantly. No significant change occurred in ammonia excretion over the three days of hypercapnia. These data argue against compensatory roles for the kidneys and urinary bladder in this species and point to internal ionic exchanges involving bone and shell.
Am J Physiol 1986 Dec
PMID:Ionic compensation with no renal response to chronic hypercapnia in chrysemys picta bellii. 378 4

Continuous 24 h intragastric pH monitoring is increasingly recommended for deciding which is the most appropriate regimen and dosage of new gastric antisecretory drugs. In order to assess its reproducibility, we have repeated the test twice on consecutive days in six patients with endoscopically proven duodenal ulcers because this type of patient seems to be the most suitable for studies on the efficacy of the above mentioned therapy. No patient received medication during the two examination days. Our data showed there was no significant difference (t = 0.31, p = 0.76) between the 24 h areas under the curve of pH profiles of the first day compared with those of the second (mean +/- SD : 3.152 +/- 681 vs 3.073 +/- 1,122). The lack of significant difference (p = 0.20) between the mean times elapsed at the various pH levels during the first and second days was further proof of the reproducibility of the method. As wells these results suggest that day-to-day reproducibility of the technique is good in duodenal ulcer patients. Therefore, its repeated use on the same patient to investigate the effects of various drugs and their different dosages on gastric acidity appears to be reliable.
Gastroenterol Clin Biol 1986 Dec
PMID:Continuous 24 hour intragastric pH monitoring: focus on reproducibility in duodenal ulcer patients. A preliminary report. 380 24

The effects of seven days' treatment with omeprazole 5 and 10 mg daily on 24 hours gastric secretion and plasma gastrin concentrations were studied in a randomised double-blinded placebo-controlled study of six male patients with healed duodenal ulcer. Omeprazole 5 mg daily reduced mean daytime and nocturnal intragastric acidity by 31.4 and 40.1%, respectively. Omeprazole 10 mg per day produced very similar reductions of 33.6 and 42.0%, respectively. Total nocturnal acid output was reduced by 63.9% and 63.2%, respectively, by omeprazole 5 and 10 mg daily. There was a large degree of inter-subject variability in response to these low doses of omeprazole. Consequently, neither dose showed a statistically significant antisecretory effect when compared with placebo. Neither dose of omeprazole significantly affected fasting levels of gastrin, but omeprazole 10 mg daily produced a significant (P less than 0.05) increase in the integrated gastrin response to a meal. The lack of consistent antisecretory effect to low dose omeprazole is in accord with previous studies. This suggests that doses of 20 mg per day or greater are required to produce a consistent effect on acid secretion.
Hepatogastroenterology 1986 Dec
PMID:Effects of low dose omeprazole on gastric secretion and plasma gastrin in patients with healed duodenal ulcer. 380 85

The relation between metabolic and functional derangement in various cardiomyopathies has not been well characterized. This information was specifically sought in a spontaneous cardiomyopathic model. Metabolic and hemodynamic parameters were obtained in glucose-perfused beating hearts of 180-200-day-old cardiomyopathic Syrian hamsters and age-matched healthy animals. This period in the cardiomyopathic hamster lifetime is intermediary between the necrotic phase and the appearance of heart failure. We used 31P nuclear magnetic resonance spectroscopy to analyze energy metabolites and intracellular pH. Cardiomyopathic hamsters had significantly higher mole fraction values for inorganic phosphate, lower phosphocreatine mole fraction as well as lower phosphocreatine/inorganic phosphate and adenosine triphosphate/inorganic phosphate ratios. Analysis of pH indicated the presence of regions of increased acidity within the heart of myopathic hamsters. Cardiomyopathic hamsters also had significantly lower left ventricular pressure, coronary flow, and myocardial oxygen consumption. Separate groups of normal and myopathic hamsters were given verapamil for 24 hours (one injection of 4 mg/kg s.c. followed by 1.2 g/l in drinking water). Verapamil-treated myopathic hamsters had evidence of markedly improved mitochondrial function when compared with untreated animals. Left ventricular pressure and coronary flow rose to normal levels. Replacing glucose by pyruvate in the perfusate of myopathic hamsters results in a marked increase in left ventricular pressure, coronary flow, and oxygen consumption with a moderate rise in phosphocreatine. Thus, 180-200-day-old cardiomyopathic hamster heart is characterized by evidence of decreased mitochondrial function, by areas of increased acidity within the heart, and by reduced left ventricular function.(ABSTRACT TRUNCATED AT 250 WORDS)
Circ Res 1986 Dec
PMID:Evaluation of the hereditary Syrian hamster cardiomyopathy by 31P nuclear magnetic resonance spectroscopy: improvement after acute verapamil therapy. 381 56

The fusogenic properties of Semliki Forest virus (SFV) and its mutants were used to follow the kinetics of acidification during the endocytic uptake of virus by BHK-21 cells. It has previously been shown that the low pH of endocytic vacuoles triggers a conformational change in the SFV spike glycoprotein, activating membrane fusion and initiating virus infection. This conformational alteration was here shown to occur in endosomes and to follow the same time course as the intracellular fusion reaction, demonstrating that fusion occurs rapidly after virus exposure to endosome acidity. The kinetics of endosome acidification were monitored using wild type (wt) SFV and fus-1, an SFV mutant with a lower fusion pH threshold. The results presented here demonstrated that wt and mutant virus were internalized with a t1/2 of 10 min, and that endosomes were acidified to the wt threshold of pH 6.2 with a t1/2 of 15 min. In contrast, endosome pH reached the fus-1 threshold of 5.3 with a much longer t1/2 of 45 min. The subsequent degradation of SFV in lysosomes had a t1/2 of 90 min. It was found that after the initial uptake of virus from the plasma membrane, its transit through the endocytic pathway, exposure to endosome acidity and eventual delivery to lysosomes were markedly asynchronous.
EMBO J 1986 Dec 01
PMID:Kinetics of endosome acidification detected by mutant and wild-type Semliki Forest virus. 381 55

To decrease gastric volume and acidity prior to anesthesia and surgery and decrease the risk of aspiration, a prospective double-blind trial comparing two H2 receptor blockers, cimetidine and ranitidine, was performed. Analysis of gastric contents revealed both drugs to be extremely effective in raising gastric pH to the 6-7 range. However, ranitidine was shown to be more effective in decreasing gastric volume.
J Oral Maxillofac Surg 1985 Dec
PMID:Effect of preoperative cimetidine and ranitidine on gastric secretion. 386 50

Changes in the acidity of osteoclasts were evaluated by direct measurement of the fluorescent intensity of osteoclasts exposed to acridine orange, a fluorescent weak base which becomes concentrated in acid-containing subcellular compartments. Parathyroid hormone (PTH) produced dose-dependent increases in fluorescent intensity; maximal increases in intensity occurred at doses between 3 and 10 micrograms PTH/ml of culture medium. Acetazolamide, a potent inhibitor of carbonic anhydrase, inhibited the increase in fluorescence induced by PTH, but this drug was less effective in reducing fluorescence in maximally than in submaximally stimulated osteoclasts, indicating that either more enzyme or more resistant enzyme was present in the PTH-stimulated cells. Because increased fluorescence of acridine orange is a sign of greater acidity, these results suggest that (1) PTH stimulates the acidity of osteoclasts, (2) carbonic anhydrase activity is necessary for maximum acidity, and (3) carbonic anhydrase is activated by PTH.
Calcif Tissue Int 1985 Dec
PMID:Stimulation of carbonic anhydrase in osteoclasts by parathyroid hormone. 393 90


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