Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “HYDROCHLORIC ACID”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 991 records · Page 55Linked to original sources
PubMed1988

Gastropathy and ketoconazole malabsorption in the acquired immunodeficiency syndrome (AIDS).

STUDY OBJECTIVE: To correlate oral ketoconazole absorption with gastric acid secretion in patients with the acquired immunodeficiency syndrome (AIDS). DESIGN: Prospective measurement of maximal acid output and oral ketoconazole absorption with and without 0.1-N hydrochloric acid. SETTING: Hospital in-patients in university medical center. PATIENTS: Ten consecutive male patients with AIDS. INTERVENTION: Maximal acid output was determined after pentagastrin stimulation in all patients. Serum ketoconazole levels were measured the day after ingestion of a 200-mg ketoconazole tablet in the fasted state. On the final day, ketoconazole was ingested with 200 mL of 0.1-N hydrochloric acid. MEASUREMENTS AND MAIN RESULTS: Maximal acid output was below 15 mEq/h in 7 of 10 patients. In all 7, the area under the serum ketoconazole concentration-time curve was below normal (1.4 +/- 0.9 mg/h.L; mean +/- SE), and absorption was normalized by hydrochloric acid (9.9 +/- mg/h.L). Two of three patients with maximal acid outputs above 15 mEq/h had normal ketoconazole absorption (15.1 +/- 6.7 mg/h.L). CONCLUSIONS: The bioavailability of oral ketoconazole is reduced in patients with AIDS, largely as a result of gastric hypochlorhydria. Ketoconazole tablets should therefore be given with acid in these patients.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Estimation of ages from racemization of an amino acid in teeth--assessment of errors under various experimental conditions.

In order to estimate ages of corpses more accurately from racemization of an amino acid (aspartic acid) in the dentine of teeth, errors resulting from various experimental conditions were assessed. The factors included for evaluation were: the sample weight, time and temperature of hydrolysis, concentration of hydrochloric acid, and the volume of the hydrochloric acid solution, each of which might have effect on resulting errors. This study revealed that alteration of the sample weight did not change the D/L ratio and that the estimated age remained constant as long as the sample weight was within the range of 3 mg and 50 mg. However, with the remaining factors, the D/L ratio changed with the alteration of conditions. The correlation can be represented by a straight line in a graph, which is a sign of the first order reaction. The coefficients of correlation were between 0.972 and 0.999, indicating their extremely high correlation with the D/L ratio. The errors expressed in estimated age values per unit of variables were: 0.02 years/min. for a time (min.) of hydrolysis; 1.5 years/degrees C for temperature of hydrolysis; 0.5 years/0.1 N (normal) for concentration of hydrochloric acid; and 0.6 years/ml for the volume of hydrochloric acid solution. Consequently, the temperature of hydrolysis was found the most influential. Alteration of values of the other four factors did not largely affect the estimation.

Age Determination by Teeth↗
PubMed1991

[An approach to removing stains and remineralization of dental fluorosis].

341 mottled teeth were bleached with 4% and 18% hydrochloric acid; the mixture of 36% hydrochloric acid, 30% hydrogen peroxide and anesthetic ether; and 30% hydrogen peroxide warmed by infra-red ray lamp. The effects were evaluated clinically. The extracted mottled and normal teeth were treated with the methods mentioned above. The decolouration effects, the structural changes of tooth surface, and the remineralization were examined by scanning electronmicroscopy and polaroid microscopy. The results showed: all of the four methods had the decolouration effects; the decolouration effect was better in the teeth with higher mineralization and the pigmentation existed more superficially; complete decolouration was 94.8% and lightened cases were 5.2%. The mechanism of decolouration seemed to be the dissolution of tooth superficial layer containing pigment. The decalcified tooth surface might be recalcified by the treatment of recalcification solution, or by saliva itself.

Adolescent↗
PubMed2004

Accuracy of the double indicator method for measurement of extravascular lung water depends on the type of acute lung injury.

OBJECTIVE: The double indicator method is sensitive to alterations in the distribution of pulmonary blood flow. This distribution is influenced by the type of lung injury. The aim of this study was to compare measurements of lung water by the double indicator method with measurements obtained by gravimetry in a direct lung injury model induced by tracheal instillation of hydrochloric acid and in an indirect lung injury model induced by the intravenous injection of oleic acid. DESIGN: Prospective, randomized laboratory study. SETTING: Animal research laboratory. SUBJECTS: Forty-two female pigs (28+/-3 kg). INTERVENTIONS: Pigs were anesthetized and ventilated and were allocated into three groups: control (n = 6), hydrochloric acid (4 mL/kg intratracheally, n = 24), or oleic acid (0.1 mL/kg intravenously, n = 12). MEASUREMENTS AND MAIN RESULTS: Hydrochloric acid instillation or oleic acid injection resulted in a similar hypoxemia and induced a two- to three-fold increase in extravascular lung water (EVLW) by gravimetry (EVLWG) at 3 hrs compared with controls. In the oleic acid group, there was a significant correlation between EVLWG and EVLW by double indicator method (EVLWDI; r =.88, p <.0001). The bias for EVLWDI - EVLWG measurements was -5.2 mL/kg (95% confidence interval, -5.7 to -4.7 mL/kg) with 95% limits of agreement of -7 to -3.4 mL/kg. In the hydrochloric acid group, there was no significant correlation between EVLWDI and EVLWG values, and the double indicator method failed to detect pulmonary edema in 65% of the animals (EVLWDI <8 mL/kg). The bias was -7.9 mL/kg (95% confidence interval, -9.3 to -6.5 mL/kg) with 95% limits of agreement of -14.4 to -1.4 mL/kg. CONCLUSIONS: The double indicator method is useful for evaluation of pulmonary edema in indirect lung injury, as induced by oleic acid, but produces misleading values in direct lung injury, as produced by hydrochloric instillation.

Analysis of Variance↗
PubMed1977

Plasma secretin concentration in anaesthetized pigs after intraduodenal glucose, fat, aminoacids, or meals with various pH.

The concentration of immunoreactive secretin in portal blood and the secretion from the exocrine pancreas were measured during intraduodenal infusion of isotonic or hypertonic saline, isotonic or hypertonic glucose, aminoacids, fat emulsion, or 0.1 mol X 1(-1) hydrochloric acid in 7 anaesthetized pigs. None of these substances, except hydrochloric acid, had any effect on plasma secretin concentration and pancreatic flow rate and bicarbonate output. Plasma secretin concentration rose significantly from 5.6 +/- 2.7 pmol X 1(-1) (mean +/- S.E.M.) to a peak value of 201.2 +/- 80.5 pmol X 1(-1) 15 min after infusion of hydrochloric acid. Pancreatic flow rate and bicarbonate output increased from 0.51 +/- 0.19 ml X h-1 (mean +/- S.E.M.) to 9.85 +/- 2.33 ml X h-1 and from 52 +/- 11 micronmol X h-1 to 1.004 +/- 290 micronmol X h-1, respectively. During intraduodenal introduction of meals with pH adjusted from 1.0 to 7.0 in 4 pigs amylase was secreted at all pH levels. However, only when pH of the meal was 1.0, resulting in an intraduodenal pH from 1.0 to 1.7 during the stimulation, was a significant increase in plasma secretin concentration and pancreatic flow rate observed from 5.5 +/- 2.8 pmol X 1(-1) (mean +/- S.E.M.) to 115.0 +/- 51.2 pmol X 1(-1) and from 0.20 +/- 0.08 ml X h-1 to 6.25 +/- 2.57 ml X h-1, respectively.

Amino Acids↗
PubMed1967

Determination of the base composition of deoxyribonucleic acid by measurement of the adenine-granine ratio.

A method is described for determination of the base composition (as guanine+cytosine or adenine+thymine content) of DNA by accurate measurement of the adenine/guanine ratio. The DNA is hydrolysed with 0.03n-hydrochloric acid for 40min. to release the purines. The hydrolysate is subjected to ion-exchange chromatography on Zeo-Karb 225. Apurinic acids are eluted with 0.03n-hydrochloric acid and then guanine and adenine are eluted separately with 2n-hydrochloric acid. Guanine and adenine are each collected as a single fraction, and the amount of base in each case is determined by measuring the volume and the extinction at suitable wavelengths. For use in the calculations, millimolar extinction coefficients in 2n-hydrochloric acid of 12.09 for adenine at 262mmu, and 10.77 for guanine at 248mmu, were determined with authentic samples of bases. The method gives extremely reproducible results: from 12 determinations with calf thymus DNA the adenine/guanine molar ratio had a standard deviation of 0.011; this corresponds to a standard deviation in guanine+cytosine content of 0.2% guanine+cytosine.

Adenine↗
PubMed2004

Risk of acute bronchospasm and bronchial hyperreactivity from inhaled acid aerosol in healthy subjects: randomized, double-blind controlled trial.

AIM: To determine the risk of developing acute bronchial spasm and bronchial hyperreactivity in healthy subjects after inhaling hydrochloric acid aerosol of different pH, since various characteristics of inhaled aerosol, particularly its acidity, contribute to the reduction in lung function in patients with a pre-existing disease. METHODS: Randomized, double-blind, placebo-controlled trial included 79 healthy volunteers. After submitting a written consent, they were randomized in 4 groups with approximately equal number of participants. Each group was exposed to acid aerosol of different pH. The respiratory lung function expressed by forced expiratory volume (FEV1), forced expiratory flow at 50% (FEF50), 75% (FEF25), and between 25% and 75% of vital capacity (FEF25/75), and non-specific bronchial reactivity were measured after inhalation of hydrochloric acid aerosol of pH 7.0, pH 5.0, pH 3.0, and pH 2.0 and compared with baseline values. Twelve subjects, who reached the threshold doses in both bronchial challenges, were tested again after receiving a systemic beta-blockade with a single oral dose of propranolol. RESULTS: Significant bronchospasm developed after the inhalation of hydrochloric acid aerosol of pH 5.0, 3.0, and 2.0. After the inhalation of aerosols of pH 5.0 and pH 2.0, all parameters of respiratory lung function (FEV1, FEF50, FEF25, and FEF25/75) significantly decreased. After the inhalation of aerosol of pH 3.0, all parameters significantly decreased except for FEF25, which showed no significant difference (1.84+/-0.46 before vs 1.58+/-0.49 after inhalation; p=0.07). The inhalation of hydrochloric acid aerosol had no significant effect on the level of non-specific bronchial reactivity irrespective of its pH. Eight out of 12 subjects tested again after pretreatment with propranolol and with no significant change in the heart rate showed no change in non-specific bronchial reactivity in comparison with the 4 subjects who reacted with a significant decrease in the heart rate (>10%), as well as in non-specific bronchial reactivity (p=0.023). CONCLUSION: Inhalation of acid aerosol in healthy subjects induced a bronchial spasm, but had no effect on non-specific bronchial reactivity except in subjects under systemic adrenergic inhibition.

Adrenergic beta-Antagonists↗
PubMed1979

Alveolar-capillary membrane permeability. Correlation with functional, radiographic, and postmortem changes after fluid aspiration.

An index of permeability of the alveolar-capillary membrane was derived from the relative extraction from the lung into arterial blood of 2 tracers, 125I-antipyrine and 51Cr-ethylenediaminetetraacetate. The effect on this index of aspirating 2 ml of isotonic saline, distilled water, or 10(-1) M hydrochloric acid per kg of body weight was studied in 3 groups of rabbits. The severity and time course of changes in the permeability index were correlated with changes in lung mechanics, gas exchange, serial chest roentgenograms, ratio of extravascular lung water to dry weight, and histologic findings. Aspiration of saline produced no change in the permeability index; aspiration of water produced a large mean +/- SEM increase in the index, from a baseline of 0.025 +/- 0.002 to 1,050 +/- 0.054 (P less than 0.001), but this value returned to baseline 15 min later. After hydrochloric acid, the permeability index increased from a baseline of 0.027 +/- 0.003 to 1.068 +/- 0.098 (P less than 0.005), with no evidence of resolution after 60 min. Changes in lung mechanics, gas exchange, and roentgenograms were smallest after aspiration of distilled water and greatest after aspiration of hydrochloric acid. The functional changes after aspiration of water and saline recovered at a rate proportional to the known clearance rates of these liquids from the lung. The changes after hydrochloric acid either showed no tendency toward recovery or, in the case of the roentgenograms, worsened with time. There were no detectable histologic abnormalities or an increase in the ratio of extravascular lung water to dry weight after aspiration of water or saline, but there were extensive histologic abnormalities and a 70 per cent increase in lung water after acid. The increase in the permeability index after aspiration of water was too transient to exert a deleterious effect. In contrast, the persistence of the increase in the permeability index after hydrochloric acid was associated with persistent functional changes attributable to the considerable increase in lung water.

Animals↗
PubMed2005

Protonation of trimipramine salts of maleate, mesylate and hydrochloride observed by 1H, 13C and 15N NMR spectroscopy.

Protonation of the tricyclic antidepressant drug trimipramine with maleic acid, methanesulfonic acid and hydrochloric acid was studied using 1H, 13C and 15N NMR spectroscopy at natural abundance. The effect of counter ions on the protonation was compared under identical conditions of solvent, concentration and temperature using homonuclear and heteronuclear one- and two-dimensional experiments. Differential protonation of the terminal tertiary amine nitrogen is determined from the indirect spin-spin couplings, chemical shifts, 13C relaxation data and variable-temperature experiments. In the maleate salt, only one of the acidic protons is involved in protonation, the other being associated with the anion moiety. 15N chemical shifts of the protonated nitrogens are nearly linearly related to the pK(a) of the constituent acid.

Antidepressive Agents, Tricyclic↗
PubMed1999

Partial vapor-phase hydrolysis of peptide bonds: A method for mass spectrometric determination of O-glycosylated sites in glycopeptides.

In this study we present a method for determination of O-glycosylation sites in glycopeptides, based on partial vapor-phase acid hydrolysis in combination with mass spectrometric analysis. Pentafluoropropionic acid and hydrochloric acid were used for the hydrolysis of glycosylated peptides. The reaction conditions were optimized for efficient polypeptide backbone cleavages with minimal cleavage of glycosidic bonds. The glycosylated residues were identified by mass spectrometric analysis of the hydrolytic cleavage products. Although glycosidic bonds are partially cleaved under acid hydrolysis, the resulting mass spectra allowed unambiguous determination of the glycosylation sites. Examples are shown with mannosyl- and mucin-type glycopeptides. Performing the hydrolysis in vapor eliminates the risk for contamination of the sample with impurities from the reagents, thus allowing analysis of the reaction products without further purification both by matrix-assisted laser desorption/ionization and electrospray ionization mass spectrometry.

Amino Acid Sequence↗
PubMed1988

Sialic acid content and proteolytic activity in gastric juice in humans. An approach for appreciating mucus glycoprotein erosion.

The combined determination in human gastric juice of sialic acid content, a marker of solubilized glycoproteins, and of acidity and proteolytic activity has been performed in 217 gastric secretory studies. Taking 1000 micrograms/h of basal sialic acid output as approximating the upper limit of normal, 33 of 34 normal subjects and 12 of 12 patients without recurrent ulcer after highly selective vagotomy had basal sialic acid output below this value while 139 of 156 duodenal ulcer patients and 15 of 15 patients with Zollinger Ellison syndrome had basal sialic acid output above it. No clear relationship between sialic acid and hydrochloric acid outputs was observed; in contrast, close positive significant correlations were noted between sialic acid and pepsin outputs: r and P values ranging, respectively, from 0.82 to 0.63 and from less than 0.001 to less than 0.02. Measurement of sialic acid output content in basal secretion could thus serve to assess mucus glycoprotein output which appears, in large part, related to gastric juice proteolytic activity.

Duodenal Ulcer↗
PubMed1979

Copper distribution and reactivity in serum following administration of cuprous oxide to rats and guinea pigs.

Total serum copper levels produced by the administration of a single dose of cuprous oxide (500 mg/kg) both s.c. and orally to rats and guinea pigs are reported 1, 5, 7 and 24 h after administration, together with caeruloplasmin oxidase activities and changes in the sulphydryl group concentrations. The highest serum copper levels were obtained one hour after oral administration to the guinea pig. Both animal species exhibited increased serum copper levels after s.c. administration and this increase persisted for a longer time than after oral administration. Caeruloplasmin oxidase activity varied in a complex manner and sulphydryl group activity was significantly depressed in all cases except after s.c. administration to the guinea pig. The latter results must be treated cautiously since they may indicate interactions between copper and the test procedures. Analysis of serum fractions separated by electrophoresis indicated that the absorbed copper is mainly transported on albumin. The dissolution of cuprous oxide by amino acids and hydrochloric acid and the absorption of cuprous oxidcations of the results are discussed in terms of their relevance to pharmacological and clinical studies.

Absorption↗
PubMedDate not supplied

GLC method for the quantification of metabolites of thymoxamine in human plasma.

A sensitive gas-chromatographic method for quantification of the pharmacologically active metabolites I-IV of thymoxamine in plasma is described. 4-(Hydroxythymyl)-(2'methylbutylaminoethyl)ether, a compound similar to metabolite I, is used as an internal standard. Metabolites I and II the internal standard are extracted with cyclohexane from alkalinized plasma followed by back-extraction into 0.1 N hydrochloric acid. After evaporating the hydrochloric acid solution, the sample is silylated with BSTFA and analyzed by gas-chromatography on a CRS 101/Carbowax 4000 column using a thermoionic detector. For subsequent determination of metabolites III and IV, the extracted plasma is hydrolyzed under conditions in which the phenol sulfates but not the glucuronide conjugates undergo cleavage. The resulting phenols (metabolite I and II) are analyzed as described above. The sensitivity threshold for all 4 compounds is approximately 5 ng/ml plasma based on a 2 ml plasma sample.

Biotransformation↗
PubMed2005

Suitability of a malachite green procedure to detect minimal amounts of phosphate dissolved in acidic solutions.

The study describes the suitability of a colorimetric method (malachite green procedure) for detection of minimal amounts of phosphate (7.3-29.1 micromol/L) in different acidic solutions (hydrochloric acid, oxalic acid, maleic acid, perchloric acid, tartaric acid, citric acid, lactic acid and acetic acid) adjusted to pH 2.0. A mixture of the respective phosphate concentrations with distilled water served as control. The experiments were run with ten repeats in series. Assessment of intra- and interassay coefficient of variation and lower limit of quantification revealed that depending on the acid used, the applied method is a reliable and suitable tool to detect and quantify minimal phosphate contents in small samples of acidic solutions that have the potential to cause erosive dental lesions.

Acids↗
PubMed1984

Factors affecting the assay of histone H1 and polylysine by binding of Coomassie blue G.

Although a mixture of calf thymus histones or the H2B and H4 fractions gave values in the Bradford assay that were similar to those for bovine serum albumin, low values were obtained with histone H1 and polylysine. The assay was found to be more sensitive for histone H1 and polylysine if the phosphoric acid concentration in the reagent was decreased or the polypeptide solutions contained low concentrations of nonionic detergents. Substitution of perchloric acid or hydrochloric acid for phosphoric acid and alcohol in the Coomassie blue G reagent provided an assay that was similar in sensitivity for histone H1 and a total histone mixture. It was suggested that the degree of metachromasia with Coomassie blue G may serve as a probe of conformational changes in histone H1.

Animals↗
PubMed1987

Developments in protein microsequencing.

The author has described here several methods which have been developed in his laboratory. These methods are explained in the following order: [I] gel electrophoresis; 1) extraction from the conventional polyacrylamide gel, 2) a new polyacrylamide gel electrophoresis system for small peptides. [II] Amino acid composition (rapid and micro methods for hydrolysis of proteins); 1) hydrolysis with a mixture of trifluoroacetic acid and hydrochloric acid, 2) vapour hydrolysis, 3) tryptophan micro-analysis. [III] Amino-terminal sequencing; 1) a sensitive detection method of Edman degradation, 2) N-terminal specific labeling method. [IV] Carboxy-terminal sequencing by carboxypeptidase digestion; 1) field desorption mass spectrometry, 2) the use of detergents or alcohols. [V] Monitoring of amino groups at the DNA binding site of protein. As mentioned in the beginning, techniques in the protein field tend to be behind comparable techniques in the DNA field. In addition, the fact that the most important biological molecules presently studied are made in such small amounts in the cell has demanded the development of techniques using precisely and quickly only micro amounts of protein. Such developments of protein chemistry techniques for purification, composition, sequencing, and chemical modification are very much needed in the cell biology field and close collaboration is required between protein chemistry, biophysics, and modern biology in order to develop the above methodology.

Amino Acid Sequence↗
PubMed1992

Electron-capture gas chromatographic procedure for simultaneous determination of amphetamine and N-methylamphetamine.

An electron-capture gas chromatographic procedure for the simultaneous determination of amphetamine and N-methylamphetamine in biological samples is described. The method employs extraction with the ion-pairing reagent bis(2-ethylhexyl)phosphoric acid, and back-extraction with 0.5 M hydrochloric acid. The hydrochloric acid phase is basified, and the amphetamines and the internal standard benzylamine are derivatized with pentafluorobenzenesulfonyl chloride prior to analysis on a gas chromatograph equipped with a capillary column. Levels of amphetamine and N-methylamphetamine have been determined in the urine and liver of rats treated chronically with (-)-deprenyl.

Amphetamine↗
PubMed2004

Proton-acceptor properties and capability for mutarotation of some glucosylamines in methanol.

N-(m-Nitrophenyl)-beta-D-glucopyranosylamine (Gln), N-(N-methylphenyl)-beta-D-glucopyranosylamine (Glm), N-beta-D-glucopyranosylpyrazole (Glp), and N-beta-D-glucopyranosylimidazole (Gli) have been synthesized. Their basicity constants, pKb, determined in methanol were, respectively, 14.99, 14.36, 15.04, and 9.74. The derivatives of secondary amines (Glm, Glp, and Gli) did not mutarotate in methanol in the presence of 3,5-dinitrobenzoic acid and hydrochloric acid. The heats of formation and entropies were calculated by the AM1 and PM3 methods for the glucosylamines and their cations under consideration of two plausible protonation centers. Thermodynamic parameters for the proton transfer in the reaction: glucosylamine + CH3OH2+ = glucosylamineH+ + CH3OH were determined and the protonation center in the glucosylamine molecule was identified. The mechanism of mutarotation of the glucosylamines is discussed and the conclusion made that formation of an acyclic immonium cation is not a satisfactory condition for the reaction to proceed.

Carbohydrate Conformation↗