SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Proximal duodenum was perfused with HCl for 5 min and the effects on blood-to-lumen clearance of 51Cr-EDTA (ED-Cl), morphology, luminal alkalinization, and blood flow determined in anesthetized rats. The rate of alkalinization was determined by back titration and blood flow assessed by laser Doppler flowmetry or by ultrasonic transit time flowmetry. Perfusion of duodenum with 30, 50 or 100 mM HCl for 5 min increased ED-Cl in a concentration-dependent manner and induced a small increase in alkalinization but had no effect on blood flow. At 55 min after cessation of perfusion with 100 mM HCl ED-Cl was 2.2-fold higher than control whereas the ED-Cl values in animals perfused with 30 or 50 mM HCl were not different from pre-acid control values. 100 mM HCl also induced an increase in 14C-mannitol and 14C-polyethylene glycol 4000 clearance, suggesting that HCl does indeed increase mucosal permeability. The 100 mM HCl-induced rise in mucosal permeability most probably reflects disturbance of mucosal integrity because three of five animals exhibited villous tip damage. The increases in ED-Cl in response to 100 mM HCl were the same in control rats as in rats with the renal pedicles ligated, indicating that the acid susceptibility is not affected by acute functional nephrectomy.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Intravenous infusion of hydrochloric acid was used as a safe, effective, and quantitative method for correction of metabolic alkalosis in two patients. The first shows the risks of intravenously administered ammonium chloride, the currently available alternative to hydrochloric acid therapy. The second shows the efficacy of intravenously administered hydrochloric acid. While breathing spontaneously throughout the period of severe alkalosis, this patient showed compensatory hypoventilation with conspicuous increase in arterial carbon dioxide pressure. Normal spontaneous ventilation returned with correction of the metabolic alkalosis.
Hydrochloric acid (0.1 M) placed on the serosal surface of a jejunal segment evoked an intestinal secretion (rats) or inhibited a net fluid absorption (cats). In rats it was demonstrated that lidocaine (placed on the serosa of periarterially denervated intestinal segments), hexamethonium (given i.v.; innervated or denervated intestines) and indomethacin (given i.v.; denervated intestines) markedly inhibited the acid induced secretion, while atropine (given i.v.) had no effect. In the cat experiments it was shown that tetrodotoxin (given close i.a. to denervated intestines) returned the rate of net fluid absorption to the control value observed before applying acid. It is concluded that exposing the intestinal serosa to an acid solution evokes a fluid secretion that is nervously mediated. Furthermore, it is proposed that prostaglandins are involved in the induction of the fluid secretion probably via a stimulation of nociceptors. It is also suggested that the results may have pathophysiological implications for some types of paralytic ileus.
A new convenient dissolution method for Fe-Rh alloys has been developed. Aqua regia has been used for the dissolution of rhodium alloy samples. However, it is difficult to dissolve high-concentration rhodium (more than 50 mass%) in aqua regia, because a rhodium-passivity on the alloys surface occurs with nitric acid. By using hydrochloric acid containing a small volume of nitric acid, Fe-Rh (24-64 mass%) alloys could be completely decomposed and dissolved under mild experimental conditions. The principal advantages of this method are simplicity and time-saving compared with other dissolution methods.
Explore the source record for details and available documents.
Young infants and approximately 30% of the elderly have low secretion of hydrochloric acid by gastric parietal cells. It has been established that low hydrochloric acid secretion can lead to decreased absorption of ferric iron. Conflicting results have been obtained in clinical studies of the effects of intraluminal gastric pH values on calcium absorption. The results of an in vitro study suggest that the chemical form of the ingested calcium and the presence of protein may influence whether high intraluminal gastric pH values affect resultant calcium solubilities in the small intestine. The effects of low hydrochloric acid secretion on zinc absorption have not been ascertained. The results of an in vitro study indicate that high intraluminal gastric pH values would not affect resultant zinc solubilities in the small intestine following pancreatin digestion of soy protein isolate supplemented with calcium and/or zinc. Considering that the diets of many elderly contain primarily plant foods and that soy protein isolate formulas are commonly fed to infants, further research is especially needed to determine the effects of low hydrochloric acid secretion on mineral bioavailabilities from high fiber and phytate containing plant foods.
Secretion of hydrochloric acid of frog gastric mucosa in vitro was studied as affected by some sterols of the cholesterol series. This effect is found to depend on both the sterol molecule structure and the substance concentration. 7-dehydrocholesterol and its products of oxidation are supposed to have a specific effect on the process of hydrochloric acid secretion. Possible mechanism of this effect is under discussion.
Hydrolysis of proteins and peptides with mercaptoethane sulfonic acid is liable to produce overestimation of the proline content owing to the production of ninhydrin-positive material (probably cysteine) which coelutes with proline on many ion-exchange analytical systems. A similar error occurs with HCl hydrolysis (especially in the presence of mercaptoethanol or thioglycollic acid) if care is not taken to oxidize cysteine during reconstitution of the hydrolysate before amino acid analysis.
Explore the source record for details and available documents.
The thymidine analogue, bromodeoxyuridine, is substituted into DNA during DNA synthesis and can be used to identify those cells which have passed through the S-phase of the cell cycle. Incorporated bromodeoxyuridine can be detected using anti-bromodeoxyuridine monoclonal antibodies which bind to the exposed bromodeoxyuridine in single-stranded DNA after a suitable denaturation step. Hydrochloric acid is the most commonly employed denaturation agent in bromodeoxyuridine monoclonal antibody methodologies. This preliminary study was to validate the hydrochloric acid denaturation step for colorectal tumour tissue infiltrated in vivo with bromodeoxyuridine. Standard immunohistochemistry and flow cytometric techniques using Bu20a were employed across a range of hydrochloric acid concentrations. Although high labelling indices were achieved using acid concentrations of 0.10 M HCl, the optimal hydrochloric acid concentration was not the same in all tumours. Sensitivity of DNA to hydrochloric acid denaturation should be carefully considered in bromodeoxyuridine methodologies using the monoclonal antibody Bu20a.
Sialic acids occupy terminal positions on gastric mucus glycoprotein where they contribute to the high viscosity of mucin. Desialylation of mucus may lead to degradation of the mucus and eventually to the breakdown of the gastric mucus barrier. The effect of a variety of damaging agents (0.1 M HCl, 2 mg ml(-1) pepsin and 2 M NaCl) on sialic acid profile was determined in pylorus-ligated rats. The relationship between sialic acid, galactose, pyruvate and the extent of gastric mucosal damage were studied. Instillation of pepsin significantly increased total sialic acid, galactose and macroscopic mucosal lesions in the stomach. Instillation of 0.1 M HCl reduced the total sialic acid but this decrease was not significant. Acidity led to a significant increase in the amount of free sialic acid in the gastric instillates and the macroscopic lesions induced by acid was not significantly different from the control animals (0.15 M NaCl). 2 M NaCl induced the macroscopic lesions in the stomach and also free sialic acid in the instillates. Pepsin potentiates the action of 2 M NaCl. In all the agents examined with the exception of acid, it was observed that an increase in free sialic acid and galactose was accompanied by gastric mucosal erosion and elevation of pyruvate concentration. It is concluded that gastric acidity alone is not inherently damaging and that resistance of gastric mucosa to destructive agents may be dependent on the integrity of the sialic acids.
Aspiration of hydrochloric acid in rabbits resulted in an increased P(A-a)O2 together with increases in both lung water volume and lung extravascular albumin. This finding suggests lung damage following acid aspiration is related to changes in capillary permeability, with pulmonary edema resulting from the movement of albumin and water into the interstitial space. Therapy with albumin and furosemide together reduced the lung water and albumin accumulation and decreased P(A-a)O2. Treatment with albumin or furosemide alone was ineffective. Caution should be exercised in administering albumin alone for therapy of pulmonary edema when plasma protein is not clearly decreased, or when increased pulmonary capillary permeability is suspected.
All cysteine and cystine in a protein are derivatized during hydrolysis in hydrochloric acid containing 3,3'-dithiodipropionic acid. The resulting derivative can be separated from other amino acids and used for quantitation of cysteine plus half-cystine. A procedure is presented for accurate determination by ion exchange chromatography and postcolumn derivatization of all amino acids from acid hydrolysis of a protein, including the Cys-derivative.
The bactericidal activity of hydrochloric acid (HCl) on different intestinal bacteria was evaluated at various pH values and time intervals. The effect of HCl was highest at pH 2 and pH 3 on strains of Campylobacter jejuni, Aeromonas hydrophila, Plesiomonas shigelloides, Yersinia enterocolitica, Salmonella spp. and Shigella spp., producing complete killing after 60 min incubation. However, at higher pH values (pH 4 and above), these organisms not only survived but they also showed evidence of rapid multiplication. In contrast, clinical and standard strains of Escherichia coli and Staphylococcus aureus were resistant to all the pH values. Highest sensitivity to HCl was observed with strains of Shigella spp. and Salmonella spp. It is conceivable that patients with normal gastric acidity should not suffer from gastroenteritis caused by these intestinal pathogens.