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At least 1,315 records · Page 73Linked to original sources
PubMed1981

Oesophageal epithelial ultrastructure after incubation with gastrointestinal fluids and their components.

Oesophageal biopsies from endoscopically normal patients were incubated in the following for up to 30 min-Ham's F10 medium:isotonic saline:0.1 N HCl:20, 2 and 0.2 mM bile acids:trypsin:pepsin:lipase; autologous gastric and duodenal juices. The biopsies were then examined by electron microscopy. No morphological change was produced by Ham's F10 or saline. HCl caused little damage. Gastric juice produced widespread severe damage, as did pepsin. Duodenal juice and the enzymes tested caused lysis and internalisation of desmosomes and peripheral cytoplasmic vacuolation. Bile acids split desmosomes and induced microvesiculation of cell membranes. Similar microvesiculation was also induced by duodenal juice. All media except hydrochloric acid eventually produced organelle damage and leaky and disrupted cells. The functional and superficial cells appeared to be able to withstand attack from these experimental media better then did prickle and basal cells. Membrane coating granules were secreted in the presence of hydrochloric acid, but not with enzymes.

Bile Acids and Salts↗
PubMed1986

Determination of fluorescent trypanocidal diamidines by quantitative thin-layer chromatography.

The fluorescent trypanocidal diamidines 2-(4-amidinophenyl)indole-6-carboxamidine dihydrochloride (I, DAPI), 2-(4-amidinophenyl)benzo[b]thiophene-6-carboxamidine dihydrochloride (II) and 2-(4-amidinophenyl)-1-benzofurane-5-carboxamidine dihydrochloride (III) were determined in plasma, urine, faeces and tissues of experimental animals using quantitative thin-layer chromatography. Samples were extracted with n-octanol after addition of sodium hydroxide and subsequently re-extracted into 0.1 M hydrochloric acid. Chromatography was performed on silica gel plates under nitrogen with n-butanol saturated with 2 M hydrochloric acid. Quantitation was performed by measuring native fluorescence using a fluorodensitometer. The respective diamidines were used as internal standards for each other to ensure precision (coefficient of variation less than 7%) and accuracy of the assay. Calibration curves were linear up to 150 ng/ml of sample solution with detection limits of 10 ng/ml of sample solution for I and III and 50 ng/ml for II. The described method has been successfully used for pharmacokinetic studies in experimental animals.

Adsorption↗
PubMed1967

Properties of ribosomal proteins from two mammalian sources.

1. Ribosomal protein fractions from rabbit reticulocytes and rat liver were prepared by extracting ribosomes with 0.2n-hydrochloric acid or guanidinium chloride and subsequent dialysis. 2. Treatment for 2.5hr. or less with 0.2n-hydrochloric acid dissolved 46-54% of the proteins, which were richer in arginine and lysine and in N-terminal alanine groups and poorer in aspartic acid and glutamic acid and in N-terminal glycine groups than the acid-insoluble proteins. 3. Protein fractions prepared from the guanidinium chloride extract of ribosomes from rat liver were usually more basic than those from rabbit reticulocytes. 4. The ratios lysine: arginine of fractions in the guanidinium chloride extracts were appreciably higher for proteins from rabbit reticulocytes than from rat liver. 5. The concentration of urea and the pH of the gel affected the rate of migration and number of bands in starch-gel electrophoresis.

Journal Article↗
PubMed2005

Determination of copper in powdered chocolate samples by slurry-sampling flame atomic-absorption spectrometry.

Chocolate is a complex sample with a high content of organic compounds and its analysis generally involves digestion procedures that might include the risk of losses and/or contamination. The determination of copper in chocolate is important because copper compounds are extensively used as fungicides in the farming of cocoa. In this paper, a slurry-sampling flame atomic-absorption spectrometric method is proposed for determination of copper in powdered chocolate samples. Optimization was carried out using univariate methodology involving the variables nature and concentration of the acid solution for slurry preparation, sonication time, and sample mass. The recommended conditions include a sample mass of 0.2 g, 2.0 mol L(-1) hydrochloric acid solution, and a sonication time of 15 min. The calibration curve was prepared using aqueous copper standards in 2.0 mol L(-1) hydrochloric acid. This method allowed determination of copper in chocolate with a detection limit of 0.4 microg g(-1) and precision, expressed as relative standard deviation (RSD), of 2.5% (n = 10) for a copper content of approximately 30 microg g(-1), using a chocolate mass of 0.2 g. The accuracy was confirmed by analyzing the certified reference materials NIST SRM 1568a rice flour and NIES CRM 10-b rice flour. The proposed method was used for determination of copper in three powdered chocolate samples, the copper content of which varied between 26.6 and 31.5 microg g(-1). The results showed no significant differences with those obtained after complete digestion, using a t-test for comparison.

Cacao↗
PubMed1985

The development of acid and pepsin (EC 3.4.23.1) secretory capacity in the pig; the effects of age and weaning. 1. Studies in anaesthetized pigs.

The development of gastric secretory capacity of hydrochloric acid and pepsin (EC 3.4.23.1) was studied in thirty-eight Large White X Landrace pigs from the litters of six sows (three pairs of two), 9-38 d of age. The pigs of each pair of sows were born within 24 h of each other. The pigs of a litter were paired according to sex and size and cross-fostered, i.e. one pig from each pair was allocated to each sow. One litter from each pair was reared entirely by the sow (milk-fed, MF) whereas the other litter was reared by the sow for 21 d, but was allowed access to solid food (210 g crude protein (nitrogen X 6.25)/kg) at 12 d and was entirely dependent on solid food after 21 d (creep-fed, CF). Following a 14-18 h fast, pigs were anaesthetized (Halothane-sodium pentobarbitone) and their stomachs perfused at a constant rate with Ringer solution. Gastric secretion was stimulated by intravenous infusion of betazole hydrochloride (Histalog) at 3 mg/kg per h for 2 h. Hydrochloric acid and pepsin were measured in the perfusate which was collected at 15-min intervals. There were significant positive correlations between stomach weight and body-weight for both MF and CF pigs. The slope of the regression line for CF pigs was significantly greater than that for MF pigs (P less than 0.01). There were significant positive correlations between maximal acid output and stomach weight for both MF and CF pigs. There were significant positive correlations between maximal pepsin output and stomach weight for both MF and CF pigs. The slope of the regression line for CF pigs was significantly different from that for MF pigs (P less than 0.01). There were also significant positive correlations between maximal pepsin output per unit stomach weight and stomach weight for both MF and CF pigs. The pattern of development of pepsin secretory capacity in both CF and MF pigs was different from that for acid secretion. Maximal outputs of acid per unit stomach weight for MF and CF pigs remained relatively constant. Maximal outputs of pepsin per unit stomach weight and per unit body-weight increased with age for both MF and CF pigs. The results indicate that pigs given access to solid food before weaning and weaned on to solid food have heavier stomachs and greater acid and pepsin secretory capacity than pigs fed entirely on sows' milk.

Aging↗
PubMed1997

Effect of lignocaine and pH on propofol-induced pain.

Propofol has the disadvantage of pain on injection. A higher partition of propofol in the aqueous phase of the preparation causes a higher incidence of pain on injection while addition of 1% lignocaine to propofol reduces pain. The low concentration of this local anaesthetic and the rapid pain relief observed indicates that mechanisms other than local anaesthesia are involved, that is change in pH. We performed a clinical study to investigate the influence of lignocaine and pH on pain during injection of 1% Diprivan. Ten parts of 1% Diprivan were mixed with one part of saline, 1% lignocaine or hydrochloric acid to achieve the same pH as that after addition of lignocaine. Diprivan 1% mixed with 1% lignocaine and with hydrochloric acid gave mean pain ratings (1-10) of 0.32 (SD 0.75) (n = 25) and 0.88 (1.30) (n = 24), respectively. These ratings were significantly lower than ratings after injection of a saline-Diprivan mixture (2.18 (2.06), n = 22). The pH of the 1% Diprivan formulation decreased after mixing with 1% lignocaine. The concentration of propofol in the aqueous phase was lower when 1% Diprivan was mixed with 1% lignocaine (0.376 g litre-1) or HCl (0.392 g litre-1) compared with 1% Diprivan and saline (0.476 g litre-1) mixed in the same proportion. Thus pH changes may modify propofol-induced pain on injection by a mechanism different from the effect of the local anaesthetic on the vascular endothelium. Our findings may explain why lignocaine mixed with propofol causes less pain than injection of lignocaine followed by propofol.

Adolescent↗
PubMed2001

Hair analysis for pharmaceutical drugs. II. Effective extraction and determination of sildenafil (Viagra) and its N-desmethyl metabolite in rat and human hair by GC-MS.

In order to study the incorporation of sildenafil (SDF) and its N-demethylated metabolite (norSDF) into hair, animal model experiments were carried out. After shaving the back hair, SDF was dosed to two sets of three male dark-agouti pigmented rats (5 weeks old) per each group at 25 mg/kg once a day for 5 successive days with intraperitoneal (i.p.) (set1) and oral administration (set2). The regrown back hair was collected 14 d after the first administration. Three typical extraction methods, using methanol-5 M hydrochloric acid, methanol-trifluoroacetic acid and 1 M sodium hydroxide, were evaluated using the rat hair samples containing SDF and norSDF. Methanol-5 M hydrochloric acid was the best extraction method in terms of high efficiency and reproducibility. The extract was purified using Bond Elut Certify columns and was derivatized with trimethylsilylimidazole: N,O-bis(trimethylsilyltrifluoroacetamide): trimethylchlorosilane (3: 3: 2) at 90 degrees C for 30 min. The trimethylsilylated products were analyzed by GC-MS using selected ion monitoring. SDF and norSDF were simultaneously detected in the rat hair. The hair concentrations were 4.9-6.3 (av. 5.8) ng/mg and 15.6-20.3 (av. 17.6) ng/mg for SDF and norSDF, respectively, with i.p. administration, and 2.6-4.1 (av. 3.6) ng/mg and 8.1-10.4 (av. 9.1) ng/mg with oral administration. The hair concentrations of norSDF were about three times higher than those of SDF, and the ratios of both compounds showed no significant difference between i.p. and oral administrations. This method was applied to the scalp hair of two patients who orally took SDF at regular intervals for the treatment of penile erectile dysfunction. The hair concentrations of SDF and norSDF in the two patients were 19.8 and 55.9 ng/mg, and 1.7 and 5.6 ng/mg, respectively.

Administration, Oral↗
PubMed1983

Effects of methylprednisolone on resolution of acid-aspiration pneumonitis.

We studied the effects of methylprednisolone sodium succinate on the pulmonary function of unanesthetized dogs for four days after aspiration of 1.5 to 2.0 mL/kg of 0.1N hydrochloric acid. Methylprednisolone sodium succinate (30 mg/kg) was administered to nine dogs at 2, 8, and 24 hours after acid aspiration. Nine animals were untreated after aspiration and served as controls. Acid aspiration caused significant increases in venous admixture and reductions in Pao2 in both groups of animals. These changes persisted for 96 hours after aspiration. There were no differences in cardiac output, venous admixture, and blood gas values between treated and untreated animals at any time. At death there were no differences between groups in amounts of lung water or histologic characteristics. We concluded that methylprednisolone administered after hydrochloric acid aspiration does not affect resolution of the injury.

Animals↗
PubMed1978

Effect of lactulose on ammonia production in a fecal incubation system.

An in vitro fecal incubation system was used to demonstrate how lactulose influences ammonia metabolism in the colon. Lactulose and other fermentable substrates (glucose, mannitol, and sorbitol), pH and organic acid were varied independently so that their different effects could be determined. Fermentable substrate caused a fall in ammonia concentration during the period of fermentation. Acidification to pH 5.0 or less, with hydrochloric acid or a lactic-acetic acid mixture, significantly reduced ammonia generation, but unlike fermentable substrates, did not lower the existing ammonia concentration. The lactic-acetic acid mixture did not reduce ammonia generation significantly below that found with acidification by hydrochloric acid. The effect of lactulose in reducing ammonia concentration is attributed to its role as a bacterial substrate in either increasing bacterial assimilation of ammonia or reducing deamination of nitrogenous compounds. The effect of low pH in reducing generation of ammonia appears to be part of a general reduction in bacterial metabolism.

Ammonia↗
PubMed1986

Cimetidine blocks antacid-induced hypergastrinemia.

The effects on fasting serum gastrin concentrations of hourly doses of magnesium and aluminum hydroxide antacid, with and without intravenous cimetidine, were determined in 8 patients with duodenal ulcer disease. Gastrin levels rose significantly over 10 h when antacid was given either as a bolus of 30 ml every hour or as a constant infusion of 0.5 ml/min (36 +/- 5 pg/ml and 33 +/- 6 pg/ml to 108 +/- 32 pg/ml and 109 +/- 22 pg/ml, respectively, p less than 0.05). This effect was specific for some component of the antacid and not for neutralization of acid per se, inasmuch as sodium bicarbonate, infused to keep gastric pH at levels at or above those of antacid, produced no significant rise in serum gastrin concentration. When intravenous cimetidine was administered simultaneously with intragastric antacid, gastrin levels did not rise. This occurred even though intragastric pH levels were actually higher with cimetidine plus antacid than with antacid alone. The ability of intravenous cimetidine to block antacid-induced hypergastrinemia was counteracted by infusing simultaneously both hydrochloric acid and antacid into the stomach. Since hydrochloric acid reacts with magnesium and aluminum hydroxide to form ionic magnesium and aluminum chloride, cimetidine most likely blocks antacid-induced hypergastrinemia by reducing acid secretion from the stomach and thereby limiting the generation of ionic magnesium and aluminum.

Adult↗
PubMed1991

High-performance liquid chromatographic determination of ethacrynic acid in human plasma.

A high-performance liquid chromatographic method for the determination of ethacrynic acid (EA) in human plasma is described. Plasma was prepared for analysis by addition of 4-(2,4-dichlorophenoxy)-butyric acid as an internal standard followed by acidification with hydrochloric acid and extraction with ethyl acetate. Separation was by isocratic reversed-phase chromatography, the column effluent was monitored at 280 nm and quantitation was performed using peak-area ratios. The linear range for EA determination was from 0.5 to 25 micrograms/ml with a lower limit of detection of 0.1 microgram/ml. The reported method is convenient, sensitive and reproducible, illustrating its usefulness for pharmacokinetic studies.

Acetates↗
PubMed1988

Disrupted retention of the classically conditioned nictitating membrane response in rabbits with aluminum-induced neurofibrillary degeneration.

Rabbits underwent classical conditioning of the nictitating membrane response (NMR) to a tone conditioned stimulus and an air puff unconditioned stimulus until they emitted 90 percent or greater conditioned responses (CRs) for two consecutive days. They then received intraventricular injection of aluminum chloride, hydrochloric acid or saline. Ten days post injection they were tested for retention of the conditioned response. Animals injected with saline or hydrochloric acid emitted an average of greater than 90 percent CRs. Aluminum injected rabbits, in contrast, emitted an average of only about 40 percent CRs. This disruption of retention of conditioning in aluminum treated rabbits could not be attributed to deficits in sensory or motor processes or to illness. Neuropathological analysis revealed widespread neurofibrillary tangle formation in the aluminum treated animals. Furthermore, the degree of neurofibrillary degeneration was significantly negatively correlated with retention of the CR. The results are considered in the context of using the rabbit NMR preparation as a model system for studying age-related conditioning disorders.

Aluminum↗
PubMed1984

Reevaluation of specificity of Crithidia luciliae kinetoplast as a substrate for detecting antibodies to double-stranded deoxyribonucleic acid.

Until now, the kinetoplast of the hemoflagellate Crithidia luciliae has been believed to be a specific indirect immunofluorescence substrate for detecting antibodies to double-stranded deoxyribonucleic acid (DNA). We have recently identified a patient in whom there was the apparent presence of procainamide-induced antinuclear antibodies at a titer of 1/1,280 on mouse kidney sections. This patient's serum also contained antihistone antibodies at a titer of 1:1,280, on the basis of a mouse kidney section histone reconstitution assay. In addition, results of an enzyme-linked immunosorbent assay (ELISA) using a pure histone preparation were strongly positive. We found that this serum produced C. luciliae fluorescence to a titer of 1:80. After pretreatment of the C. luciliae substrate with hydrochloric acid to remove histones, this serum no longer produced kinetoplast fluorescence. However, this serum again produced kinetoplast fluorescence when assayed on a hydrochloric acid-treated C. luciliae substrate that had been reconstituted with purified histone. The negative kinetoplast reactivity after hydrochloric acid treatment of the C. luciliae substrate suggests that the antibody is reacting with acid-extractable nucleic acids, not necessarily the double-stranded DNA, or the antibody is directed against nuclear proteins such as DNA-histone complexes of deoxyribonucleoprotein. The finding that reactivity reappeared after the histone was reconstituted back to the hydrochloric acid-treated C. luciliae substrate suggests that the primary antibody in this serum is directed against DNA-histone complexes or histone alone. These findings strongly suggest that the kinetoplast of C. luciliae contains antigens other than double-stranded DNA and that is not a specific substrate for the detection of double-stranded DNA antibodies by indirect immunofluorescence.

Adult↗
PubMed2005

Chemical extraction of organic carbon to reduce the leaching potential risk from MSWI bottom ash.

The performance of extraction solvents, including organic and inorganic solvents, for organic carbon extraction from municipal solid waste incinerator (MSWI) bottom ash was evaluated. The total carbon (TC) extracted was used to ascertain the efficiency of extraction solvents and the reduction of dissolved organic carbon (DOC) leaching potential was used to evaluate the capacity of solvents to minimize environmental impacts of MSWI bottom ash over short- and long-term considerations in landfill sites. Extract final pH value was a prominent parameter affecting TC extraction. The higher efficiency was obtained at the lower extract final pH and acid or neutral condition was necessary to achieve approximately 30% of TC extraction from bottom ash. On the basis of the results of TC extraction, the efficiency of organic carbon reduction was evaluated using organic carbon leaching potential. Hydrochloric acid was the best solvent to extract organic carbon in controlled pH conditions. Hydrochloric acid reduced the organic carbon leaching potential of MSWI bottom ash by about 68% at neutral leaching pH.

Carbon↗
PubMed2004

Immunocytochemical characterization of rat brainstem neurons with vagal afferent input from the stomach challenged by acid or ammonia.

Exposure of the gastric mucosa to backdiffusing acid is signalled to the brainstem via vagal afferents. This study examined whether exposure of the Sprague-Dawley rat stomach to hydrochloric acid (HCl) or ammonium hydroxide (NH4OH), a noxious chemical produced by Helicobacter pylori, activates different vagal afferent pathways as reflected by different circuitries in the medullary brainstem. Two hours after intragastric treatment with HCl or NH4OH the activation of neurons in the nucleus tractus solitarii at the rostrocaudal extension of the area postrema (NTSAP) was visualized by c-Fos immunohistochemistry and their chemical coding characterized by double-labelling immunohistochemistry. Exposure of the rat gastric mucosa to HCl (0.15-0.5 M) or NH4OH (0.1-0.3 M) led to a concentration-dependent expression of c-Fos in the NTSAP. The number and distribution of NTSAP neurons activated by 0.35 M HCl and 0.3 M NH4OH were similar; the highest number of activated neurons occurring in the medial part of the NTSAP. Some 60% of the NTSAP neurons activated by intragastric HCl and NH4OH stained for the high affinity glutamate transporter EAAC1, while some 30% contained calbindin or neuropeptide Y. Glutamate receptors of the N-methyl-D-aspartate type were found on approximately 50% of the c-Fos-positive cells in the NTSAP, whereas tachykinin NK1, NK2 and NK3 receptors were present on 5-10% of the activated neurons. The similar number and distribution of c-Fos-expressing neurons within the NTSAP and their identical chemical coding indicate that exposure of the rat stomach to backdiffusing concentrations of HCl and NH4OH activates the same vagal afferent-NTSAP pathway.

Amino Acid Transport System X-AG↗
PubMed1987

Skin reactions to irritants assessed by polysulfide rubber replica.

Skin damage after application of experimental irritants was evaluated under blind conditions and by the use of polysulfide rubber replica. Closed patch tests with 7 different irritants, solvents and empty chambers were applied to 16 volunteers, and the skin damage was evaluated visually and by a replica technique after 24, 48 and 96 h. We found that 3 of the irritants (sodium lauryl sulphate, hydrochloric acid and croton oil) were capable of causing specific and significantly different patterns of skin damage. The patterns could be divided into papular (hydrochloric acid, croton oil) and non-papular (sodium lauryl sulphate, sapo kalinus, sodium hydroxide) types. Nonanoic acid caused a non-paular pattern, but propanol, used as a solvent, by itself also produced a non-papular pattern. The time between application of the irritant and appearance of the characteristic alteration in the skin surface differed, depending on the irritant applied.

Adult↗
PubMed1977

[Study of gastric secretion in white rats with a chronic gastric fistula on endotoxin exposure].

The author carried out a study on the stomach secretion in white rats endotoxin shock, induced by venous adminsitration of endotoxin, obtained from Escherichia coli. Stomach fistula was made on the rats in advance and the stomach juice was collected under the condition of chronic experiment. The amount of stomach juice was estimated in mililiter per hour as well as the content of free hydrochloric acid, total aidity and electrophoresis of proteolytic enzymes. There was a statistically significnat lowering of the amount of stomach juice, diminuation of free hydrochloric acid and of total acidity acidity as well as diminution of complete disappearence of its proteolytic activity in the rats after endotoxin action.

Animals↗
PubMed1989

Prospective evaluation of high-dose bethanechol in investigation of esophageal chest pain.

We compared the value of bethanechol 80 micrograms/kg subcutaneously, acid infusion with a 0.1 normal hydrochloric acid, and edrophonium 80 micrograms/kg intravenously as provocative agents to reproduce chest pain and manometric alterations in 72 patients with noncardiac chest pain. No patient developed typical chest pain and manometric alteration with acid infusion, while five (6.9%) patients developed these changes with edrophonium and four (5.6%) with bethanechol. Only one patient developed diagnostic changes exclusively with bethanechol. All patients tested with bethanechol developed some degree of local pain or significant cholinergic symptoms, with two patients requiring atropine for relief. Side effects from edrophonium were infrequent (28% of patients tested) and did not require atropine administration. We conclude that, using the parameters of typical chest pain and the development of manometric alterations as proof of the esophageal origin of chest pain, bethanechol at 80 micrograms/kg adds little information beyond that obtainable with edrophonium. Further, the high incidence of bethanechol-related side effects at 80 micrograms/kg suggests that this dose should not be generally recommended.

Bethanechol↗