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PubMed2005

Patients with gastro-oesophageal reflux disease and cough have impaired laryngopharyngeal mechanosensitivity.

BACKGROUND: Laryngopharyngeal sensitivity (LPS) is important in preventing pulmonary aspiration and may be impaired by anaesthesia and stroke. It has been suggested that gastro-oesophageal reflux disease (GORD) may also impair LPS, although the underlying mechanism is unclear. The aim of this study was to compare LPS in patients with chronic cough and GORD with healthy subjects and to determine the effect of laryngopharyngeal infusions of both acid and normal saline on LPS. METHODS: Fifteen patients with chronic cough and GORD and 10 healthy subjects without GORD underwent LPS testing using the fibreoptic endoscopic evaluation of swallowing with sensory testing (FEESST) technique. LPS, as measured by the lowest air pressure required to elicit the laryngeal adductor reflex (LAR), was determined both before and after laryngopharyngeal infusions of normal saline and 0.1 N hydrochloric acid performed on separate days. RESULTS: The mean baseline LAR threshold of the patient group was significantly higher (9.5 mm Hg, range 6.0-10.0) than in normal subjects (3.68 mm Hg, range 2.5-5.0; p<0.01). Retest thresholds were not significantly different. In normal subjects LAR thresholds were significantly raised after acid but not after saline infusion (p = 0.005). There were no complications associated with the procedure. CONCLUSIONS: Patients with cough and GORD have significantly reduced LPS to air stimuli compared with healthy subjects which could potentially result in an increased risk of aspiration. Exposure to small amounts of acid significantly impaired the sensory integrity of the laryngopharynx.

Adult↗
PubMed2004

Relative acidifying activity of anionic salts commonly used to prevent milk fever.

High cation diets can cause milk fever in dairy cows as they induce a metabolic alkalosis reducing the ability of the cow to maintain calcium homeostasis at the onset of lactation. Adding anions to the diet can offset the effect of the high cation forages by inducing a mild metabolic acidosis, restoring the ability to maintain calcium homeostasis. The difference in mEq of dietary cations and anions (DCAD) is most often expressed as (Na(+) + K+) - (Cl- + S(--)). This equation implies that a mEq of chloride and a mEq of sulfate are equipotent in their ability to alter acid-base balance of the cow. Using blood and urine pH to monitor effects on acid-base balance, experiments were conducted to test the relative acidifying activity of various sulfate and chloride anion sources in nonpregnant, nonlactating Jersey cows. Across all experiments, chloride proved to have about 1.6 times the acidifying activity of sulfate. Calcium and magnesium, ignored by the common DCAD equation, had a small but significant alkalinizing effect when accompanying chloride or sulfate. The ranking of the anion sources tested at a dose of 2 Eq/d, from most to least potent urine acidifier, was hydrochloric acid, ammonium chloride, calcium chloride, calcium sulfate, magnesium sulfate, and sulfur. These data should allow more accurate prediction of the response of late gestation cows to dietary cation-anion manipulation.

Acid-Base Equilibrium↗
PubMedDate not supplied

Overview and status of mouthguard bleaching.

Since the bleaching of vital teeth using a tray delivery system with a 10 percent carbamide peroxide first became common knowledge in March, 1989, there has been much discussion, improvement, and questions concerning the process and the various products available. This article presents an overview of its history, the variations in techniques, and questions concerning safety, including the impact on tooth structure, the pulp, soft tissue of the mouth, and systemic ingestion. It divides currently available products according to their composition, into either a carbamide peroxide with and without carbopol, a hydrogen peroxide of varying concentrations, a hydrochloric acid, or other categories. It discusses the various delivery mechanisms and comments on their apparent effectiveness, as well as reflecting the current knowledge base of the profession.

Carbamide Peroxide↗
PubMed1987

Salivary changes in solution pH: a source of individual differences in sour taste perception.

The role of saliva in sour taste perception was investigated in a series of 4 experiments. In one pair of experiments, solution pH was measured before and after acetic, citric or hydrochloric acid solutions were mixed with saliva either normally in the oral cavity or after saliva was directly added to solutions. The results showed that large increases in solution pH occurred over a wide range of acid concentrations and that the changes in pH were related to individual salivary flow rates; greater increases in solution pH occurred among those individuals with higher flow rates. The other pair of experiments measured taste threshold and suprathreshold responses to different volumes of acids. The results demonstrated that individuals with high salivary flow rates were less sensitive to the taste of acids and that large volumes of acid were more easily perceived. The pattern of findings suggest that saliva-induced changes in solution pH are important in sour taste perception.

Adolescent↗
PubMed1978

Exocrine secretion of canine pancreas perfused extracorporeally.

A canine gastroduodenopancreatic block was isolated and perfused extracorporeally with homologous blood. This preparation was used for studying stimulated exocrine secretion of the pancreas. Stimulants were infused intra-arterially. Both vagi were stimulated electrically. Hydrochloric acid or L-phenylalanine were instilled intragastrically. Pancreatic secretion induced by secretin and during HCl instillation was rich in bicarbonate and poor in total protein. Pancreatic secretion obtained during the infusion of normal saline, cholecystokinin, bethanechol chloride or acetylcholine chloride and during instillation of amino acid as well as during electrical stimulation of vagi, contained less bicarbonate and more protein than secretin-induced secretion.

Acetylcholine↗
PubMed1997

Stimulation of pulmonary C fibres by lactic acid in rats: contributions of H+ and lactate ions.

1. The contributions of H+ and lactate ions to the stimulation of single pulmonary C fibres by lactic acid were examined in anaesthetized and artificially ventilated rats. 2. Lactic acid injected into the right atrium caused a transient decrease in arterial blood pH (pHa) and a short but intense burst of afferent activities in pulmonary C fibres, whereas sodium lactate had no effect. The fibre activity usually reached a peak within 1-1.5 s, with an onset latency of < 1 s, and returned to the baseline in 5 s. 3. The injection of hydrochloric acid at the same pH as that of lactic acid did not significantly decrease pHa, nor did it stimulate any C fibres studied. 4. Formic acid has a pKa value (the negative logarithm of the dissociation constant) almost identical to that of lactic acid; thus, its injection decreased pHa to the same degree as did the injection of lactic acid. However, the response of C fibres to lactic acid was 134% stronger than that to formic acid. 5. We conclude that H+ is primarily responsible for the activation of pulmonary C fibres by lactic acid, probably through a direct effect of H+ on these afferent endings. The lactate ion, by itself, does not activate C fibres, but it seems to potentiate the stimulatory effect of H+ on these afferents.

Action Potentials↗
PubMedDate not supplied

[Influence of acids and metal salts on associates of pheophytin and its derivatives in binary mixtures of solvents].

The experimental investigation of the influence of HCl and Zn, Cd and Cu acetates on association of pheophytin alpha and rodin g7 was carried out in water-ethanolic (4 : 1) media. It is shown that during acidation of a binary solvent mixtures containing pheophytin alpha associate, the formation of product with the absorption maximum 702nm takes place, which is the pigment associated form. The formation of the same product is found under the action of metal acetates on pigment associated complexes. It is assumed that under treatment of water-ethanolic solutions of associates of pheophytin and its derivatives by hydrochloric acid and metal salts. at first introduction of these compound molecules into the aggregate sphere takes place and then the incorporation of the H+ and Me2+ positive ions into the centre of an associate dimer cell occurs along with the transformation of the structure of the pigment associated complexes.

Cadmium↗
PubMed2006

[Contribution to the erythroquine and thalleioquine reaction].

The 8,8'-biquinoline-5,5'-diones 2A are formed by the erythroquine and thalleioquine reaction from the 6-methoxyquinolines 1 as model compounds. The red substances 2A react with hydrochloric acid to yield the yellow biquinolinedihydrochlorides 3. The structure of 3b dihydrate is determined by X-ray crystal analysis. The redox properties of 2A are investigated by voltammetric methods.

Hydrochloric Acid↗
PubMed2004

Effects of celecoxib on acid-challenged gastric mucosa of rats: comparison with metamizol and piroxicam.

Selective COX-2 inhibitors have been shown to produce fewer gastrointestinal adverse reactions than classical NSAIDs. Nevertheless, these new agents may worsen and delay the healing of experimentally induced gastric ulcers in animals. In this study, we compared the effects of a selective COX-2 inhibitor (celecoxib), a preferential COX-1 inhibitor (piroxicam), and a nonnarcotic analgesic (metamizol) on normal gastric mucosa of rats and, on the other hand, in a setting of preexisting acute gastric lesions induced by 0.6 N hydrochloric acid. Under normal conditions, only piroxicam produced appreciable gastric lesions. However, after acid challenge the three assayed drugs induced significant macroscopic and microscopic damage. Myeloperoxidase activity as an index of neutrophil infiltration was elevated with celecoxib and piroxicam on normal gastric mucosa. On inflamed mucosa, celecoxib augmented enzymatic activity at the lower dose, which was parallelled by an increase in the interleukin 1beta level. Acid instillaton produced a significant rise in PGE2 content at 7 hr. Drug treatment after acid challenge decreased prostaglandin values in all cases, although to a lesser extent than after single drug dose administration. COX-2 mRNA expression was visible 1 hr after acid application, whereas COX-2 protein could only be detected at 7 hr. Piroxicam increased both expression levels. All NSAIDs enhanced transforming growth factor alpha and epidermal growth factor receptor immunoreactivity around the acid-induced lesions. It is concluded that selective COX-2 inhibitors, like conventional NSAIDs, impair the healing of gastric damage, and therefore special attention should be paid in patients with gastric pathologies.

Animals↗
PubMed1977

Acetylsalicyclic acid and gastrointestinal propulsion in the rat.

The possible influence of moderate amounts of acetylsalicyclic acid (ASA) on gastric emptying, duodeno-gastric reflux and small bowel propulsion was studied in rats with permanent gastric and duodenal tubes. The ASA-containing or the control solution was introduced intra-gastrically half an hour before the simultaneous administration of differently labeled radioactive test meals into the stomach and the duodenum. ASA was given as 7.5 or 15.0 mM solution in 100 mM hydrochloric acid or in 100 mM sodium chloride. After 15 minutes the gastrointestinal propulsion was examined. No effect of the ASA treatment was noted. No increase in duodeno-gastric reflux was found in the ASA-treated animals.

Animals↗
PubMed1991

Liquid chromatographic method for the determination of the carbohydrate moiety of glycoproteins. Application to alpha 1-acid glycoprotein and tissue plasminogen activator.

A rapid procedure is described for the qualitative and quantitative analysis of the carbohydrate composition of glycoproteins by liquid chromatography with light-scattering detection. The analysis was carried out in three steps. First, the glycoprotein samples were purified by a two-step purification on a Sephadex G-25 column with a 90% yield. Second, the selectivity of the separation and the sensitivity of detection of monosaccharides, as methyl glycosides obtained by direct methanolysis of glycoproteins, were improved by modified simplex optimization of the methanolysis parameters (temperature, methanolic hydrochloric acid strength and reaction time) determined at 66 degrees C, 1.2 M and 8.1 h for alpha 1-acid glycoprotein (alpha-AGP) and 73 degrees C, 1.5 M and 12.5 h for tissue plasminogen activator (tPA). Finally, the method was applied to the determination of the carbohydrate moiety of the two N-glycosylated glycoproteins alpha-AGP and tPA.

Acetylglucosamine↗
PubMed1993

Role of reflux oesophagitis and acid in the development of columnar epithelium in the rat oesophagus.

The role of reflux oesophagitis and acid in the development of oesophageal columnar epithelium was investigated in the rat. Twenty-four animals underwent total gastrectomy and oesophagojejunostomy, inducing reflux of duodenal contents into the oesophagus, and were divided into two groups: an 'acid' group, which drank syrup water with hydrochloric acid (pH 1.8), and a 'non-acid' group, which drank only syrup water (pH 6.5). Four rats were killed at 4, 8 and 12 weeks after surgery. Reflux oesophagitis was found in the lower portion of the oesophagus in all cases. Columnar epithelium was observed in the oesophagus of one rat in the non-acid group at week 8 and of three in the acid group at week 12. These results indicate that the development of columnar epithelium of the oesophagus is preceded by reflux oesophagitis and that acidic conditions may promote this change. Columnar epithelialization may result from metaplasia of squamous epithelium as well as from upward extension of columnar epithelium.

Animals↗
PubMed1990

Differences in metabolite content between intact pancreases and their perchloric acid extracts. A 2D 1H/31P correlation NMR study.

Perchloric and hydrochloric acid extracts of intact pancreases from healthy rats and from rats with experimental acute pancreatitis were analysed using 2D 1H/31P correlation NMR spectroscopy. Major differences were found in the 2D maps between the extracts and the intact tissues. In the case of the intact diseased pancreas the prominent 31P signal at the phosphodiester region has been assigned in our previous work as lecithin/taurocholate complex. However, the signal found in the same chemical shift region in extracts of diseased pancreases as well as healthy ones, is identified here as the phosphodiester residue of oligoribonucleotides. In these extracts additional 31P signals were found and assigned as phosphomonoester and phosphodiester hydrolysis products of RNA. The amounts of these compounds, as a function of the acid concentrations were determined, and conditions for their minimization were defined.

Animals↗
PubMed1984

Identification of hydrogen selenide and other volatile selenols by derivatization with 1-fluoro-2,4-dinitrobenzene.

A procedure is described for the trapping and identification of hydrogen selenide and methyl selenol ( CH3SeH ). The volatile selenols were generated by reducing selenious acid or dimethyldiselenide with Zn dust and hydrochloric acid under a stream of nitrogen and passing into a trapping solution composed of 50 mM 1-fluoro-2,4-dinitrobenzene plus 83 mM sodium bicarbonate in 67% dimethylformamide:33% water. The selenols react rapidly to form stable dinitrophenyl (DNP) selenoethers that can be extracted into benzene; these are easily identified by TLC, HPLC, or mass spectrometry. Hydrogen selenide is trapped in 90-99% yield, primarily as the di-DNP- monoselenide with a trace of di-DNP- diselenide .

Chromatography, High Pressure Liquid↗
PubMed2005

Decomposition of energetic chemicals contaminated with iron or stainless steel.

Contamination of chemicals or reaction mixtures with iron or stainless steel is likely to take place during chemical processing. If energetic and thermally unstable chemicals are involved in a manufacturing process, contamination with iron or stainless steel can impact the decomposition characteristics of these chemicals and, subsequently, the safety of the processes, and should be investigated. The goal of this project was to undertake a systematic approach to study the impact of iron or stainless steel contamination on the decomposition characteristics of different chemical classes. Differential scanning calorimetry (DSC) was used to study the decomposition reaction by testing each chemical pure, and in mixtures with iron and stainless steel. The following classes of energetic chemicals were investigated: nitrobenzenes, tetrazoles, hydrazines, hydroxylamines and oximes, sulfonic acid derivatives and monomers. The following non-energetic groups were investigated for contributing effects: halogens, hydroxyls, amines, amides, nitriles, sulfonic acid esters, carbonyl halides and salts of hydrochloric acid. Based on the results obtained, conclusions were drawn regarding the sensitivity of the decomposition reaction to contamination with iron and stainless steel for the chemical classes listed above. It was demonstrated that the most sensitive classes are hydrazines and hydroxylamines/oximes. Contamination of these chemicals with iron or stainless steel not only destabilizes them, leading to decomposition at significantly lower temperatures, but also sometimes causes increased severity of the decomposition. The sensitivity of nitrobenzenes to contamination with iron or stainless steel depended upon the presence of other contributing groups: the presence of such groups as acid chlorides or chlorine/fluorine significantly increased the effect of contamination on decomposition characteristics of nitrobenzenes. The decomposition of sulfonic acid derivatives and tetrazoles was not impacted by presence of iron or stainless steel.

Calorimetry↗
PubMed1979

Quantitative thin-layer chromatography: thin-film fluorescence scanning analysis of adriamycin and metabolites in tissue.

A rapid, non-hydrolytic thin-film fluorescence scanning method is described for the quantitation of adriamycin and metabolites in tissues. Adriamycin, with daunomycin added as the internal standard, was extracted from tissue homogenate which contained 500 micrograms of oxalic acid, with ice-cold 0.5 N hydrochloric acid--85% isopropanol, separated by thin-layer chromatography, and quantitated in situ via a fluorescence scanning technique. This method has a sensitivity to 0.05 microgram per gram of tissue.

Animals↗
PubMed1976

Gas chromatographic determination of acetic acid in industrial atmosphere and waste water.

A gas chromatographic (GC) method is presented for the specific determination of acetic acid in air and total ionic acetate (as acetic acid) in industrial waste water. Atmospheric air samples are collected in fritted midget bubblers containing aqueous sodium carbonate solution; wastewater samples are treated directly with sodium carbonate. Both air and water samples are concentrated by evaporation of water, and the acetic acid is regenerated by the addition of hydrochloric acid. The amount of acetic acid is determined quantitatively on a porous polymer packed column by internal standardization with propionic acid. GC conditions are described for the suppression of "ghosting" and "tailing" caused by adsorption phenomena associated with the GC behavior of organic acids.

Acetates↗
PubMed1999

The effects of two antiinflammatory pretreatments on bacterial-induced lung injury.

BACKGROUND: Two antiinflammatory therapies that have been effective in preventing acid-induced lung injury were evaluated. Specifically, their effects on a subsequent bacterial-airspace challenge were compared. Bacteria were instilled 24 h after acid-induced lung injury. Pseudomonas aeruginosa PAO-1 was used as the bacteria, because its effects in healthy lungs was documented previously. METHODS: New Zealand white rabbits were anesthetized and three pretreatments were administered: (1) pentoxifylline pretreatment (a 20-mg/kg bolus dose and then 6 mg x kg(-1) x h(-1) given intravenously), (2) 1 ml anti-tumor necrosis factor alpha antiserum given intravenously, or (3) normal saline given intravenously. The pretreatment doses were shown previously to prevent acid-induced lung injury. Then 1.2 ml/kg hydrochloric acid (HCl), pH 1.25, was instilled into the rabbits' right lungs. All the animals underwent mechanical ventilation for 8 h. Twenty-four hours after the acid instillation, the rabbits were anesthetized again and 2 ml/kg (10(9) colony forming units/ml) PAO-1 was instilled into their left lungs. The rabbits' breathing was aided by mechanical ventilation for another 8 h, and then they were killed and exsanguinated. RESULTS: Both pretreatments attenuated the acid-induced lung injury of the noninstilled left lungs. Arterial oxygen tension and the lung edema of pretreated, acid-exposed animals were significantly and almost equally improved (compared with no pretreatments) by either of the pretreatments. However, when the bacteria were instilled into the left lungs 24 h after the acid injury, the pentoxifylline pretreatment but not the anti-tumor necrosis factor alpha pretreatment prevented much of the bacteria-induced lung injury. Pentoxifylline pretreatment significantly improved the measurements of left lung edema and epithelial and endothelial permeability. There was also a trend for improved oxygenation in the pentoxifylline-pretreated and infected animals. In contrast, the anti-tumor necrosis factor alpha pretreatment did not prevent the bacteria-induced lung injury and increased some of the measurements of lung injury. CONCLUSIONS: Two antiinflammatory therapies that prevented acid-induced lung injury to the noninstilled left lungs had significantly different effects on a subsequent bacteria-induced lung injury to the left lungs. The therapies differed in their mechanism of tumor necrosis factor alpha blockade, and this may have affected the bacteria-induced injury to the lungs.

Animals↗