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At least 1,207 records · Page 67Linked to original sources
PubMed1977

Effect of changes in the intragastric milieu on competence of the gastro-oesophageal region. A study in normal subjects.

Acid-reflux studies were carried out in 10 healthy subjects in the basal state, during continuous infusion of pentagastrin (0.015 mug/kg body-weight) after bolus injection of insulin (0.2 IU/kg bodyweight), and after intragastric instillation of 200 ml hydrochloric acid. Basal gastro-oesophageal sphincter pressure and rise in intragastric pressure on leg raising were measured by means of perfused catheters. The increase of intragastric acidity during infusion of pentagastrin and during insulin-induced hypoglycaemia was not accompanied by changes in the competence of the gastro-oesophageal region. Instillation of hydrochloric acid was followed by a significant enhancement of the reflux tendency. Changes in intragastric pressure-rise were not demonstrated in any of the series of investigation. Gastric acid secretion and its significance at the evaluation of the results of reflux studies by means of pH-measuring equipment has not been clarified in patients. It can therefore reasonably be demanded of future acid reflux studies that details have to be stated with regard to acid secretion, and that these should be taken into account at the assessment of the results of the study.

Adult↗
PubMed1975

Blood pressure response to both carotid occlucion and asphyxia, as influenced by intracerebroventricular injection of norepinephrine or epinephrine.

The carotid occlusion response (COR) in dogs was inhibited by 50 and 58% after intracerebroventricular injection of norepinephrine and hydrochloric acid, both at the pH 2.9. After norepinephrine at pH 7, this inhibition was 22%. The COR inhibition was 24% with epinephrine solution of pH 2.4 whereas the same solution at pH 7 produced no inhibition. The injection of drugs solved in acid solution, lead to a decrease in the pH of the cerebrospinal fluid. The response to asphyxia was inhibited by 50% after injection of norepinephrine at pH 2.9, but not after epinephrine at pH 2.4 or hydrochloric acid. Bradycardia was caused by epinephrine in neutral or acid solution and a decrease of arterial blood pressure was seen after epinephrine or norepinephrine in neutral or acid solution.

Animals↗
PubMed1979

[Animal model of acute respiratory insufficiency by HCl aspiration in Lewe mini-pigs].

Acute respiratory insufficiency or adult respiratory distress syndrome is a common medical emergency in intensive medicine complicated by high mortality. To study the acute respiratory insufficiency under standardized conditions an animal model in Lewe-mini-pigs has been developed. This model is based on aspiration pneumonitis produced by intrabrochial atomisation of 0.2 N hydrochloric acid. General anesthesia was performed by neuroleptanalgesia. In all animals the profound changes in gas exchange, pulmonary mechanics and hemodynamics as well as quasi-static volume-pressure relationships after hydrochloric acid aspiration were described. The results suggest that this model is suitable to outline the profound changes in pulmonary function in this type of acute respiratory insufficiency.

Acute Disease↗
PubMed1986

Influence of tryptophan loading on urinary excretion of anthranilic acid and 3-hydroxyanthranilic acid by men and women as determined by alkali flame ionization gas chromatography.

A gas chromatographic method with alkali flame ionization detection is described for the determination of urinary total (free and conjugated) anthranilic acid (AA) and 3-hydroxyanthranilic acid (HAA) as their pentafluorobenzyl esters. Prior to analysis, urine was hydrolysed using hydrochloric acid in a boiling water bath. The highest AA and HAA yields were obtained with 4 M hydrochloric acid and a hydrolysis time of 4 h. The coefficients of variation of the between-run analyses of AA and HAA at the endogenous level were 7.2 and 5.8%, respectively. The average recovery for both substances was 84%. The method described has been used to study the excretion of AA and HAA in the urine of healthy males and females before and after an oral load of tryptophan. Furthermore, the influence of oral contraceptives has been investigated. Results indicate that for both sexes the excretion of AA in the urine was higher than that of HAA, except after tryptophan loading. The excretion of AA by women was higher than by men. For HAA, the results of both sexes were comparable. Furthermore, for neither of the sexes was a diurnal variation of AA or HAA observed. After tryptophan loading, the formation of HAA was increased by more than that of AA. Results obtained for women on oral contraceptives indicate a hormonal-induced inhibition of AA formation.

3-Hydroxyanthranilic Acid↗
PubMed1990

Identification and quantitation of phenylalanine, tyrosine and dihydroxyphenylalanine in the thoracic nervous system of the locust, Schistocerca gregaria, by gas chromatography-negative-ion chemical ionisation mass spectrometry.

Phenylalanine, tyrosine and dihydroxyphenylalanine (DOPA) were identified unambiguously and quantitatively determined in single ventral thoracic nerve cords from the locust, Schistocerca gregaria, by gas chromatography-negative-ion chemical ionisation mass spectrometry. Deuterium-labelled analogues of each compound were added to a single ventral thoracic nerve cord in hydrochloric acid; the tissue was homogenised and the suspension centrifuged. The remaining hydrochloric acid was eliminated azeotropically by repeated additions of acetonitrile followed by evaporation under a stream of nitrogen and the resultant residue derivatised by reaction with hexafluoroisopropanol and pentafluoropropionic anhydride. Under negative-ion chemical ionisation conditions, the hexafluoroisopropanol-pentafluoropropionyl derivatives produced characteristic ions which were sufficiently abundant to be suitable for selected-ion monitoring. This method is highly specific and gave a limit of detection below the nanogram level. The amounts of phenylalanine, tyrosine and DOPA in a single ventral thoracic nerve cord were, respectively, 194 +/- 81, 347 +/- 88 and 11 +/- 11 ng per tissue.

Animals↗
PubMed2001

[Determination of sucralose in foods by HPLC].

A method for the determination of sucralose in various foods by RI-HPLC and ion chromatography with a pulsed amperometric detector (PAD-IC) was developed. Chopped or homogenized samples were packed into cellulose tubing with 0.01 mol/L hydrochloric acid containing 10% sodium chloride and were dialyzed against 0.01 mol/L hydrochloric acid for 24 hours. The dialyzate was passed through a Bond Elut ENV cartridge, and the cartridge was washed with 0.2 mol/L NaOH and water. Sucralose was eluted from the cartridge with methanol. The extract was taken to dryness in an evaporator and the residue was re-dissolved in water. Sucralose was separated on an Inertsil ODS-3V column with a mobile phase of acetonitrile-water (15:85) and an RI detector. It was also determined on a CarboPak PA1 column with a mobile phase of 100 mmol/L NaOH-75 mmol/L CH3COONa, using a PAD detector. The recoveries of sucralose from various kinds of foods spiked at 50 micrograms/g and 200 micrograms/g ranged from 88-105%. The detection limit in samples was 10 micrograms/g for RI-HPLC and 1 microgram/g for PAD-IC.

Chromatography, High Pressure Liquid↗
PubMed2001

[Spectrophotometric determination of nitrite ion with acridine red based on the nitrosation reaction].

A new spectrophotometric method for the determination of nitrite ion was studied. The method is based on the nitrosation reaction of acridine red with nitrite ion in hydrochloric acid medium. The decolorization of acridine red by the reaction with nitrite was used to spectrophotometric determination at 525 nm. The optimum experimental conditions have been confirmed and 6 mol.L-1 hydrochloric acid is 1.5 mL; 5 x 10(-4) mol.L-1 acridine red is 2.0 mL, the reaction time is 20 min. On the selected conditions, Beer's law is obeyed and the linear range for the determination is 0.025-0.5 microgram.mL-1 NO2-.28 coexistent ions were examined and no serious interference for most of ions was observed. The method has been applied to determine nitrite ion in four water samples with satisfactory results. The relative standard deviation was less than 2.6% for 5 measurements in each water sample. A preliminary relation mechanism is supposed.

Hydrochloric Acid↗
PubMed1980

Effect of splanchnectomy and vagotomy on the pepsinogen response to intragastric acid.

Perfusion of the stomach in the anaesthetized rat with saline acidified to pH 2.5 with hydrochloric acid induced a small but significant release of pepsinogen into the perfusate. This stimulus to secretion was unaffected by splanchnectomy but was abolished by vagotomy. It is concluded that a modest degree acid secretion in the rat may stimulate pepsinogen secretion by a vagal pathway.

Animals↗
PubMed2003

Determination of organic acids in tobacco by capillary isotachophoresis.

Nine organic acids and phosphate have been separated and quantified in tobacco by capillary isotachophoresis. Two operating systems for the separation were found: hydrochloric acid (10 mmol l(-1)) adjusted with beta-alanine to pH 2.9 plus 0.1% poly(vinylpyrrolidone) was used as the leading electrolyte and 10 mmol l(-1) nicotinic acid as the terminating electrolyte and hydrochloric acid (10 mmol l(-1)) including 5.5 mmol l(-1) 1,3-bis[tris(hydroxymethyl)methylamino]propane plus 0.1% poly(vinylpyrrolidone) was used as the leading electrolyte and 5 mmol l(-1) 2-morpholinoethanesulfonic acid as the terminating electrolyte. Linearity was observed from 0.008 to 0.100 mmol l(-1) with a coefficient of determination (r2) of 0.999. The separation of anions was achieved in less than 16 min. The minimal sample pretreatment and relatively low running cost make isotachophoresis a good alternative to existing methods.

Acids↗
PubMed1994

Hair analysis for drugs of abuse. VIII. Effective extraction and determination of 6-acetylmorphine and morphine in hair with trifluoroacetic acid-methanol for the confirmation of retrospective heroin use by gas chromatography-mass spectrometry.

A procedure for the detection and determination of 6-acetylmorphine (6AM) and morphine in rat and human hair is described. The efficiency of extraction of 6AM and morphine from hair was compared between five extraction methods using methanol, 0.1 M hydrochloric acid, methanol-5 M hydrochloric acid (20:1), helicase and methanol-trifluoroacetic acid (TFA) (9:1). Methanol-TFA was found to be the best solvent for extracting 6AM and morphine with minimum hydrolysis and maximum extraction efficiency of 6AM. The extraction rates of 6AM and morphine from heroin abuser's hair with methanol-TFA reached a plateau after 8-10 h. After the extraction from hair with deuterated internal standards added, the extract was purified by Bond Elut Certify in the usual manner. The 6AM and morphine were then derivatized with bis(trimethylsilyl)acetamide, which were characterized by GC-MS with electron impact ionization. Confirmation was accomplished by comparing their retention times and the relative abundances of major four selected ions with those of the standards. Quantification was based on the deuterated internal standards. Linearity was obtained in the concentration range 0.1-50 ng/mg. The overall recoveries after solvent extraction and solid-phase purification were 95% for 6AM and 97% for morphine. The limit of detection for confirmation was 0.2 ng/mg. The coefficients of variations for 6AM and morphine at concentrations of 4 ng/mg were generally less than 8%. 6AM was stable during extraction with methanol-TFA (9:1) at room temperature. This method was applied to the elucidation of heroin drug history by using hair sectional analysis.

Adult↗
PubMed2002

Rapid spot tests for detecting the presence of adulterants in urine specimens submitted for drug testing.

Several adulterants are used to mask tests for abused drugs in urine. Adulterants such as "Klear" and "Whizzies" contain potassium nitrite, and "Urine Luck" contains pyridinium chlorochromate (PCC). The presence of these adulterants cannot be detected by routine specimen integrity checks (pH, specific gravity, and temperature). We developed rapid spot tests for detecting these adulterants in urine. Addition of 3% hydrogen peroxide in urine adulterated with PCC caused rapid formation of a dark brown color. In contrast, unadulterated urine turned colorless when hydrogen peroxide was added. When urine contaminated with nitrite and 2 to 3 drops of 2N hydrochloric acid were added to 2% aqueous potassium permanganate solution, the dark pink permanganate solution turned colorless immediately with effervescence. Urine contaminated with nitrite liberated iodine from potassium iodide solution in the presence of 2N hydrochloric acid. Urine adulterated with PCC also liberated iodine from potassium iodide in acid medium but did not turn potassium permanganate solution colorless. Urine specimens from volunteers and random urine samples that tested negative for drugs did not cause false-positive results. These rapid spot tests are useful for detecting adulterated urine to avoid false-negative drug tests.

False Negative Reactions↗
PubMed1994

Effect of hypochlorhydria due to omeprazole treatment or atrophic gastritis on protein-bound vitamin B12 absorption.

OBJECTIVE: To investigate the effects of hypochlorhydria and acidic drink ingestion on protein-bound vitamin B12 absorption in elderly subjects. METHODS: Absorption of protein-bound vitamin B12 was examined in elderly normal subjects (n = 8), and in hypochlorhydric subjects due to omeprazole treatment (n = 8) or with atrophic gastritis (n = 3). Subjects underwent absorption tests of protein-bound vitamin B12 ingested with water, cranberry juice and 0.1 N hydrochloric acid. RESULTS: Protein-bound vitamin B12 absorption was lower in the omeprazole-treated group (0.50%) compared to the normal group (1.21%; p < 0.001). With cranberry juice ingestion, the omeprazole-treated group showed an increase in absorbed protein-bound vitamin B12 (p = 0.025). With dilute hydrochloric acid ingestion, there was a further increase in vitamin B12 absorption (p < 0.001). CONCLUSION: Omeprazole causes protein-bound vitamin B12 malabsorption, and ingestion of an acidic drink improves protein-bound vitamin B12 absorption.

Absorption↗
PubMed1996

Upper aerodigestive cancer in battery manufacturers and steel workers exposed to mineral acid mists.

OBJECTIVE: To assess the risk of cancer from inhalation of mineral acid mists. METHODS: A cohort study and nested case-control study of upper aerodigestive tumours were carried out in men employed since 1950 at two battery plants and two steel works in Britain. The cohort was identified from personnel records and included 2678 men with definite exposure to acid mists (mainly sulphuric acid), 367 with possible exposure, and 1356 who were unexposed. Mortality was compared with that in the national population by the person-years method. Cases of upper aerodigestive cancer were identified from death certificates and cancer registrations, and their exposure to acids was compared with that of age matched controls (five per case) from the same plant by conditional logistic regression. RESULTS: In follow up to 31 December 1993, 93% of men were traced, including 1277 who had died. Among the men definitely exposed to acid mists, overall mortality was less than in the national population (standardised mortality ratio (SMR) 0.92, 95% confidence interval (95% CI) 0.85-0.98) as was mortality from all cancers (SMR 0.92, 95% CI 0.79-1.05) and specifically from cancer of the larynx (SMR 0.48, 95% CI 0.01-2.70) and lung (SMR 0.98, 95% CI 0.78-1.22). A total of 15 incident or fatal cases of upper aerodigestive cancer were identified during follow up. When these men were compared with controls, risk was moderately increased in those who had worked for at least five years in jobs entailing exposures to sulphuric or hydrochloric acid in excess of 1 mg/m3 (OR 2.0, 95% CI 0.4-10). CONCLUSIONS: These findings are consistent with those from other studies which have indicated a hazard of upper aerodigestive cancer from acid mists. However, they indicate that any risk from exposures to sulphuric and hydrochloric acid below 1 mg/m3 is small.

Aerosols↗
PubMed1990

Acid-induced esophagobronchial-cardiac reflexes in humans.

Esophagobronchial reflexes have been demonstrated in both the cat and dog models. In order to determine if these reflexes are present in humans and if they are vagally mediated, a prospective sequential study was initiated. One hundred thirty-six individuals referred for esophageal manometric measurements were studied. Measurements of airway flow, arterial oxygen saturation, and pulse rate were performed before and after intraesophageal infusion of sterile water, normal saline solution, and 0.1 N hydrochloric acid. Highly significant reductions in heart rate, airway flow, and arterial oxygen saturation were noted after infusion of normal saline and 0.1 N hydrochloric acid compared with baseline water infusion (P less than 0.001). Graded responses were noted with heart rate: the more acidic the solution infused, the larger the decrement of heart rate. Atropine abolished postsaline/acid decrements of airway flow, arterial oxygen saturation, and heart rate. It is concluded that acid-induced, vagally mediated esophagobronchial reflexes are present in humans.

Atropine↗
PubMed1995

Central versus peripheral site of action of the tachykinin NK1-antagonist RP 67580 in inhibiting chemonociception.

1. Many studies indicate an involvement of substance P in the transmission of nociceptive stimuli, without, however, presenting any conclusive evidence as to its exact site and mode of action. The present experiments tested the involvement of substance P in the mediation of chemical nociception using the non-peptidic specific tachykinin NK1-receptor antagonist, RP 67580 (2-[1-imino-2-(2-methoxyphenyl-ethyl]-7,7diphenyl-4-perhydroiso indolone (3aR, 7aR)). 2. Mean arterial pressure (MAP) and intragastric pressure (IGP) were measured in anaesthetized rats. The reflex changes of these parameters in response to i.p. or s.c. injections of hydrochloric acid or capsaicin were taken to indicate nociception. 3. Intravenous administration of RP 67580 up to 5 mg kg-1 had little influence on the reflex changes in MAP or IGP in response to hydrochloric acid or capsaicin. In contrast, the sensitization of rats to i.p. capsaicin by preinjection of prostaglandin E2 was significantly reduced by 1 mg kg-1 RP 67580. 4. Intrathecal injection of 5 micrograms RP 67580 inhibited the reflex changes of MAP and IGP in response to i.p. or s.c. capsaicin whereas the inactive enantiomer RP 68651 was ineffective. 5. The results indicate that spinal NK1-receptors are involved in the acute transmission of chemically induced pain, while such receptors in the periphery take part in the sensitization by prostaglandin E2. The rather minor ability of i.v. RP 67580 to inhibit the acute nociceptive reflex is attributed to an insufficient penetration of the blood-brain-barrier.

Analgesics↗
PubMed1986

Acid perfusion of duodenal ulcer craters and ulcer pain: a controlled double blind study.

Although early studies attributed an important role to acid in the pathogenesis of duodenal ulcer pain, recent reports are conflicting. The aim of the present study is to determine whether direct acidification of the duodenal ulcer crater in symptomatic patients reproduces ucler pain. Patients with endoscopically diagnosed duodenal ulcers were studied. No premedication or sedation was given. A washing tube was passed via the endoscope and 0.1 N hydrochloric acid as well as normal saline were sequentially administered on to the ulcer crater, the sequence of infusion being randomised and double blind. Forty patients were studied. Sixteen developed typical ulcer pain during acid infusion compared with four with saline (p less than 0.005). Ten patients who developed pain on acid were rechallenged with acid after their pains disappeared. Typical pain recurred in all. Twenty patients without duodenal ulcer did not develop pain when 200 ml of 0.1 N hydrochloric acid was infused into the duodenum. Acid therefore appears to have a definite role in the pathogenesis of duodenal ulcer pain although other factors may also be important.

Adult↗
PubMed2002

[Study on hydrolysis conditions of Dioscorea nipponica with uniform design method].

OBJECTIVE: To optimize hydrolysis conditions of Dioscorea nipponica so as to provide parameters for extracting diosgenin in industry. METHODS: The optimum hydrolysis conditions were investigated using diosgenin as an index with uniform design and high performance liquid chromatography method. RESULTS: The optimum conditions were as follows: the hydrochloric acid concentration was 2.5 mol/L, solid-liquid rate was 1:5, the reaction temperature was 140 degrees C, the reaction time was 4.0 h, the mix round speed was 120 r/min. CONCLUSION: The content of diosgenin under the optimum hydrolysis conditions is raised, and the hydrochloric acid concentration should be strictly controlled because of its large influences on the results.

Dioscorea↗
PubMed1996

Effects of indium and iron ions on in vitro calcium phosphate precipitation and crystallinity.

The elution characteristics of indium and iron ions from six kinds of dental casting alloys were studied in vitro. A certain amount of indium (0.01-1.70 mg/cm2) was solubilized from the surface of only one prosthetic semiprecious brand (Miro Bright) in either 1% lactic acid or 0.05% hydrochloric acid solutions. The elution of iron was below the detection limit or < 0.01 mg/cm2. We also studied the stimulatory effects of indium and ferric ions on the calcium phosphate precipitation in the absence and presence of an inhibitor (phosvitin, a phosphoprotein purified from egg yolks). Indium and ferric ions promoted the reaction, and their stimulatory effects were stronger than the inhibitory effects of phosvitin (250 micrograms/ml). These facts suggest that indium, but not iron, could be eluted into the mouth, and that the eluted indium may stimulate the formation of oral calcium phosphate precipitates, counteracting the inhibition by saliva-derived phosphoproteins. The effects of these metal ions on calcium phosphate precipitates were also studied using both X-ray diffractometry and infrared spectrophotometry. It was shown that both indium and ferric ions decreased the grade of crystallinity of the calcium phosphate precipitates (hydroxyapatite).

Chelating Agents↗