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PubMed1986

Impaired antibiotic entry into lung tissue following acid injury.

The purpose of this study was to compare the lung tissue burden of intravenous (i.v.) and intrabronchial (i.b.) cefazolin, using a standardized hydrochloric acid injury to the lungs. Ten mongrel dogs were anesthetized with pentobarbital and artificially ventilated. Following administration of cefazolin i.v. (N = 5) or i.b. (N = 5), lung biopsies were obtained at 6 hourly intervals. Simultaneous serum levels were also determined. The effective time (Teff) was defined as the period during which all serum and lung specimens demonstrated antibiotic activity exceeding 8 mcg/gm. These levels should provide comprehensive coverage of common lung and wound pathogens that are sensitive to cefazolin. Teff for the i.v. group was 1 hour, while aerosolized cefazolin never produced lung levels exceeding 8 mcg/gm. Thus, these findings suggest an explanation for cefazolin failure in gram negative pneumonia.

Aerosols↗
PubMed2001

Recovery of zinc(II) from HCl spent pickling solutions by solvent extraction.

Recovery of zinc(II) from HCl spent pickling solutions by solvent extraction using CYANEX921, CYANEX923, CYANEX302, tributyl phosphate, and ALAMINE336 extractants was studied. Tributyl phosphate was selected as suitable extractant. It permitted both effective zinc(II) extraction and the stripping from loaded organic phase with water. The presence of iron(II) did not affect zinc extraction, and only negligible oxidation of iron(II) was observed during extraction experiments. CYANEX reagents and ALAMINE336 extracted zinc(II) strongly, but the stripping with water was ineffective. Moreover, a significant oxidation of iron(II) to iron(III) occurred during extraction. Each of three reagents (CYANEX923, ALAMINE336 and TBP) extracted iron(III) very well. Thus, if iron(III) was present in the spent pickling solution, prior to the extraction it had to be reduced to iron(II). The oxidation was low for tributyl phosphate and high for CYANEX923 and ALAMINE336. CYANEX302 was inactive both for zinc(II) and iron(III) and could not be used for extraction of zinc(II) from spent pickling hydrochloric acid solutions.

Environmental Pollutants↗
PubMed1990

Prostaglandin E2 formation by rat gastroduodenal tissue following intragastric acid perfusion.

Rat gastroduodenal mucosa forms prostaglandin (PG) E2. However, little is known about regional differences in PGE2 formation or the effect of gastric hydrochloric acid (HC1) perfusion on regional PGE2 formation. In this study, the rats were divided into 3 groups. Group 1 received intravenous (i.v.), 1 Ml/h, and intragastric (i.g.), 8 ml/h, perfusions of saline simultaneously for 3 h. Group 2 received saline i.v. and 0.15 N HC1 i.g., 8 ml/h. Group 3 was injected with a bolus of asprin (ASA), 60 mg/kg, followed by ASA, 40 mg/kg/h i.v., and 0.15 N HC1 i.g.. The gastric aspirates were analyzed for volume and pH. Segments of gastroduodenal tissue from the fundus, corpus, antrum, and duodenum were minced and then incubated in 1 ml of 5 mM Tris buffer, pH 8.4, for 30 sec with mixing; the incubate was assayed for PGE2 by radioimmunoassay. Intragastric HC1 decreased the pH of aspirate without producing gastric mucosal lesions. However, when combined with i.v. ASA, ulcer formation was present in all animals (p less than 0.05). PGE2 was formed by isolated tissue from four different gastroduodenal regions. The duodenum formed significantly greater amounts than the fundus, antrum, or corpus, which were similar. Intragastric HC1 produced a trend toward increased PGE2 formation (pmol PGE2/mg tissue) in the fundus, 143 +/- 36 to 237 +/- 57; corpus, 87 +/- 13 to 200 +/- 57; antrum, 157 +/- 28 to 224 +/- 65; and duodenum, 235 +/- 56 to 338 +/- 51. However, statistical significance was not reached.

Animals↗
PubMed1977

Effect of acid on the motility of the oesophagus of the pig with experimentally induced oesophagitis.

The mucous membrane of the oesophagus of 6 pigs was experimentally damaged with hydrochloric acid to create changes similar to reflux oesophagitis. The passage of contrast medium through the oesophagus of the pigs was observed by using spot radiography and pressure measurements. Acid contrast medium caused spasms and nonperistaltic pressure waves during the act of swallowing. Conventional contrast medium traversed the oesophagus normally and the swallowing complex was normal. On the basis of this experimental model it is concluded that the acidity of a bolus is of fundamental importance in the aetiology of spasms in oesophagitis.

Animals↗
PubMed1970

The structure of anticapsin, a new biologically active metabolite of Streptomyces griseoplanus.

1. Physical and analytical data obtained on crystalline anticapsin indicated the empirical formula C(9)H(13)NO(4). Spectral data (u.v., i.r. and proton magnetic resonance) and formation of l-tyrosine on hydrolysis revealed the functionalities and carbon skeleton of the new epoxy keto amino acid. 2. The optical properties of anticapsin (optical rotatory dispersion and circular dichroism) permitted assignment of absolute configuration to the new metabolite. 3. Treatment of anticapsin with hot methanolic hydrochloric acid followed by acetylation gave C(18)H(19)NO(5), the alpha-alkoxycyclohexenone derivative. Analysis of the nuclear-magnetic-resonance and mass spectra of the latter allowed its structure to be determined and confirmed the assigned structure of anticapsin.

Amino Acids↗
PubMed1996

The role of acid in the pathogenesis of indomethacin-induced gastric antral ulcers in the rat.

BACKGROUND: The role of acid in the pathogenesis of indomethacin-induced ulcers of the rat gastric antrum was studied by comparing the effects of pretreating animals with both long-acting (loxtidine, AH22216) and short-acting (ranitidine and cimetidine) inhibitors of acid secretion. RESULTS: Ranitidine and cimetidine were much weaker at inhibiting antral damage when compared to their reported potencies as antisecretory agents. In marked contrast, loxtidine and AH22216 inhibited indomethacin-induced antral ulcers at doses similar to their reported potencies as inhibitors of acid secretion. Histological analysis at doses causing near maximal inhibition of macroscopic damage revealed an almost complete absence of ulcers but a large and significant increase in mucosal damage due to superficial erosions. Hourly dosing with hydrochloric acid reversed the protective effect of ranitidine, cimetidine and loxtidine on macroscopic damage and, histologically, this was associated with the widespread appearance of antral ulcers and a reduction in the proportion of mucosal damage caused by superficial erosions. CONCLUSIONS: The results of this study suggest that the pathogenesis of nonsteroidal anti-inflammatory drug (NSAID)-induced antral ulcers involves at least two stages: (1) an initial acid-independent formation of mucosal erosions followed by (2) an acid-dependent conversion of erosions to frank ulcers. Clinically, drugs that suppress acid completely for long periods may be very effective in preventing NSAID-induced gastric antral ulcers.

Animals↗
PubMedDate not supplied

Inhibition of acidic corrosion of carbon steel by some mono and bis azo dyes based on 1,5 dihydroxynaphihalene.

Inhibition of the corrosion of carbon steel in hydrochloric acid solution by some mono- and bis-azo dyes based on 1,5-dihydroxynaphthalene was studied in relation to the concentration of inhibitors using weight loss and potentiostatic polarization techniques. The percentage inhibition efficiency calculated from two methods is in a good agreement with each other. The inhibition mechanism of the additives was ascribed to the formation of complex compound adsorbed on the metal surface. The adsorption process follows Freundlich adsorption isotherm. The formation of the complex compound was studied by conductometric and potentiometric titrations. The stability constants of the Fe-complexes were determined using the latter technique and related to the inhibition efficiency.

Azo Compounds↗
PubMed1997

Acid-induced increase in duodenal mucosal alkaline secretion in the rat involves the L-arginine/NO pathway.

Duodenal mucosal alkaline secretion increases in response to hydrochloric acid exposure. The tentative role of nitric oxide (NO) in the mediation of this response was investigated. The mucosal alkaline output by a duodenal segment was recorded by in situ titration in chloralose-anaesthetized rats. In some experiments the duodenal blood flow was estimated by laser-Doppler flowmetry. Exposure of the duodenum to acid (0.01 M HCl, 5 min) increased the alkaline secretion by approximately 85%. The NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 10 mg kg-1 intravenously or 0.3 mM intraluminally) blocked the secretory increment after mucosal acid exposure. Mean arterial pressure and basal alkaline secretion were markedly raised, whereas duodenal blood flow was decreased, when L-NAME was given intravenously (i.v.). Intraluminal (i.l.) administration left mean arterial pressure as well as duodenal blood flow unaltered, and the duodenal mucosal alkaline secretion was only slightly elevated. The stereoisomer NG-nitro-D-arginine methyl ester (D-NAME) had no effect on either basal or acid-induced duodenal alkaline output. In animals receiving L-arginine (10 mg kg-1 min-1 i.v., or 3 mM i.l.) and L-NAME, the acid exposure elicited an increase in duodenal mucosal alkaline secretion, similar to that observed in controls. The results suggest that the acid-induced increase in duodenal mucosal alkaline secretion involves NO synthesis, which takes place close to the lumen, probably within the mucosa.

Animals↗
PubMed1975

Detection of mannitol formation by bacteria.

A test is described by means of which formation of mannitol from fructose by lactic acid bacteria can be readily detected. The test is based on removal of interference of residual fructose by dehydration with hydrochloric acid followed by thin-layer chromatography.

Bacteriological Techniques↗
PubMed1982

Prolonged exposure to acid, chlorine, or tetracycline in the drinking water: effects on delayed-type hypersensitivity, hemagglutination titers, and reticuloendothelial clearance rates in mice.

Water treated with hydrochloric acid, alkaline and acidic solutions of sodium hypochlorite, or tetracycline was given to outbred mice for 120 days. Significant experimental variability was found in the delayed-type hypersensitivity responses in the mice drinking tetracycline treated water (1 mg/ml). One group of mice consuming tetracycline treated water had suppressed foot pad responses to sheep erythrocytes which may have been related to a change in the enteric microflora or a variation in tetracycline resistance. There was a significant reduction in uncorrected reticuloendothelial clearance rates (K) in the mice consuming acidified water (pH 2.0), and this appeared to be a result of reduced spleen weight and spleen to body weight ratios. However, there were no significant differences in the carbon clearance rates that were corrected for spleen, liver, and body weights. Responses in other treatment groups were not significantly affected. The findings of this study suggest that the routine use of additives in drinking water for rodents should be considered as a potential source of variation in immune responses.

Animals↗
PubMed1984

Corneal burns: a quantitative comparison of acid and base.

A quantitative comparison is made of the effects of two of the most completely dissociating representatives from the pH spectrum, sodium hydroxide and hydrochloric acid, on oxygen uptake by the corneal epithelium. Based on initial observations, a 6 to 1 time ratio in the exposure period (acid, 60 seconds; base, 10 seconds) was found necessary to localize and define similar aerobic effects by the 2 agents on their concentration scales. A further dosage adjustment factor was required, a 5/1 concentration ratio of acid to base, to achieve near parity of the major depressive thresholds of those 2 agents, as well as to illustrate in the resulting graphical model several unique features of each in their aerobic effects on corneal tissue at lower concentrations.

Animals↗
PubMed1993

Nicotinic cholinergic influences in pancreatic secretion induced by intraduodenal alkaline and acid solutions in the rabbit.

1. The effect of hexamethonium on the exocrine pancreatic response to intraduodenal acidification and alkalinization, and the secretin and VIP release after these stimuli, was studied. 2. The hydroelectrolyte secretion after hydrochloric acid and sodium carbonate perfusion was reduced by hexamethonium treated (322 +/- 44% of maximum response in flow rate to sodium carbonate perfusion in untreated animals vs 140 +/- 12% in pretreated animals, and 252 +/- 19% of maximum response in flow rate to HCl in untreated animals vs 166 +/- 11% in pretreated animals). 3. However, hexamethonium has no effect on secretin plasma levels after either intraduodenal acidification or alkalinization. 4. On the contrary, the ganglion blocker significantly (P < 0.01) reduced plasma VIP levels in response to intraduodenal HCl (maximum response 320 +/- 74% in untreated vs 184 +/- 44% in hexamethonium-treated animals). 5. Plasma VIP levels showed a similar increase in both untreated (maximum response: 151 +/- 12%) and ganglion blocked animals (170 +/- 26%) in response to sodium carbonate. 6. These data suggest the existence of complex neural mechanisms in the exocrine pancreatic response to intraduodenal stimuli, these mechanisms being different depending on the intraduodenal stimulus.

Acids↗
PubMed1980

Acid-sensitive oesophagus.

The aim of the present study was to investigate whether any differences could be demonstrated between patients with reflux symptoms and an acid-sensitive oesophagus (group I) (positive acid perfusion test) and a matched control group of patients with reflux symptoms and an acid-insensitive oesophagus (group II) (negative acid perfusion test) with respect to other oesophageal function tests (manometry, acid clearing and acid reflux (12-h continuous pH recording)). The two groups consisted of 47 and 46 patients, respectively. No differences were demonstrated between the two groups with respect to gastro-oesophageal sphincter pressure, acid-clearing ability, and acid reflux (irrespective of the criterion used for reflux). From the study it may be concluded that not only hydrochloric acid but other components of the reflux material may be responsible for producing symptoms of gastro-oesophageal reflux.

Adult↗
PubMed1993

Partial characterization of a glycosylphosphatidyl-inositol (GPI) in porcine thyroid cultured cells.

The aim of this study was to provide information on the structure of glycosylphosphatidylinositol (GPI) and to characterize this novel phospholipid isolated from pig thyroid. We investigated the incorporation of different radioactive precursors: [3H]glucosamine, [3H]inositol, [3H]oleic acid, [32P]orthophosphate and demonstrated the presence of these moieties in the structure of GPI. After labelling and hydrochloric acid hydrolysis, the major part of radioactivity comigrated with glucosamine used as marker. Cleavage of GPI by nitrous acid deamination indicated the presence of a glycosidic bond between the lipid moiety and glucosamine. The fatty acid composition of diacylglycerol was also studied by gas chromatography. Oleic acid was found preferentially to other fatty acids. In a previous paper we reported that a chronic treatment with 0.1 mU/ml thyrotropin (TSH) of thyroid cultured cells for 3 days produced a large increase in the turnover rate of GPI and concomitantly the release of a water-soluble product of GPI hydrolysis: an inositolphosphateglycan (IPG). These findings confirm that GPI may play a role in membrane signalling systems and thyroid cell regulation.

Animals↗
PubMed1976

Preferential acid-catalyzed hydrolysis of the formamide linkage of N'-formylkynurenine in frozen solution.

Acid-catalyzed hydrolysis of the formamide linkage of N-acetyl-N'-formyl-L-kynurenineamide in frozen dilute hydrochloric acid solution followed first-order kinetics, yielding N-acetyl-L-kynurenineamide as the sole reaction product. The maximum rate of reaction in the frozen solution was found at around -7.5 degrees and approximated that of the reaction in liquid solution at 40 degrees. By freezing the dilute acid solution at -8 degrees the reaction was accelerated by 60 times compared with that in super-cooled liquid solution at the same temperature.

Formamides↗
PubMed1997

Studies on the antisecretory, gastric anti-ulcer and cytoprotective properties of glycine.

Glycine, a neutral amino acid has been studied for its ability to inhibit gastric secretion and to protect the gastric mucosa against chemically and stress-induced ulcers. Acid secretion studies were undertaken in pylorus-ligated rats with and without glycine treatment. Experimental gastric lesions were induced by hypothermic-restraint stress, indomethacin and necrotizing agents including 80% ethanol, 0.2 M sodium hydroxide and 0.6 M hydrochloric acid in rats. The level of nonprotein sulfhydryl compounds and gastric wall mucus were also measured in the glandular stomach of the rats following ethanol-induced gastric lesions. The results of this study demonstrate that glycine dose dependently reduced the gastric secretions in rats. Pretreatment with glycine significantly protected animals against stress-, indomethacin- and necrotizing agents induced gastric lesions. The antiulcer activity of glycine was associated with significant inhibition of ethanol-induced depletion of nonprotein sulfhydryls and gastric wall mucus. In conclusion, this study demonstrates that glycine possesses significant antiulcer and cytoprotective activity. However, further detailed studies are warranted to establish the mechanism(s) of action, and to determine its role in the prophylaxis and treatment of gastric ulcer disease.

Animals↗
PubMed2003

Inducible nitric oxide synthase is involved in acid-induced gastric hyperemia in rats and mice.

The role of different isoforms of nitric oxide synthase (NOS) in the gastric mucosal hyperemia, induced by 155 mM luminal hydrochloric acid (pH approximately 0.8) without a barrier breaker, was investigated. Rats were anesthetized with Inactin (120 mg/kg ip), and mice were anesthetized with Forene (2.2% in 40% oxygen gas at 150 ml/min); the gastric mucosa was exteriorized. Gastric mucosal blood flow was measured with laser-Doppler flowmetry (LDF) in rats treated with Nomega-nitro-l-arginine (l-NNA; unspecific NOS inhibitor), l-N6-(1-iminoethyl)lysine [l-NIL; inducible (i) NOS inhibitor], or S-methyl-l-thiocitrulline [SMTC; neuronal (n) NOS inhibitor], 10 mg/kg, followed by 3 mg. kg-1. h-1 iv, in iNOS-deficient (-/-) and nNOS(-/-) mice. mRNA was isolated from the gastric mucosa in iNOS(-/-) and wild-type (wt) mice, and real-time RT-PCR was performed. The effect of 155 mM acid on gastric mucosal permeability was determined by measuring the clearance of 51Cr-EDTA from blood to lumen. LDF increased by 48 +/- 13% during 155 mM HCl luminally, an increase that was abolished by l-NNA, SMTC, or l-NIL. In iNOS wt mice, LDF increased by 33 +/- 8% during luminal acid. The blood flow increase was attenuated substantially in iNOS(-/-) mice. RT-PCR revealed iNOS mRNA expression in the gastric mucosa in the iNOS wt groups. The blood flow increase in response to acid was not abolished in nNOS(-/-) mice (nNOS-sufficient mice, 39 +/- 18%; heterozygous mice, 25 +/- 19%; -/- mice, 19 +/- 7%). Mucosal permeability was transiently increased during 155 mM HCl. The results suggest that iNOS is constitutively expressed in the gastric mucosa and is involved in acid-induced hyperemia, suggesting a novel role for iNOS in gastric mucosal protection.

Administration, Topical↗