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PubMed1975

Alkali and acid burns of the rabbit eye: uptake of intravenously injected Na125I and Na131I into the cornea and iris.

Rabbit eyes were burned either with 1 N sodium hydroxide or 1 N hydrochloric acid. In a previous part of the study (Obenberger and Babický, 1974) authors measured the aqueous flow using intravenous injections of Na125I and Na 131I. In the present study the uptake of iodine into the cornea and iris is investigated in the same eyes. Caustic injuries of both types initially cause changes in the specific activity of the aqueous affecting the uptake of iodine into the examined tissues.

Animals↗
PubMed1986

Industrial ecotoxicology "acid rain".

The acid rain phenomenon was studied in the province of Cordoba, Argentina. This study, based on a previously outlined framework, determined the anthropogenic origin of the low pH due to the presence of industrial hydrochloric acid wastage. This industrial ecotoxicological phenomenon seriously affected the forest wealth, causing a great defoliation of trees and shrubs, with a lower effect on crops. A survey on its effects on human beings has not been carried out, but considering the corrosion caused to different metals and its denouncing biocide effect on plants and animals, we should expect to find some kind of harm to the health of the workers involved or others engaged in farming, and even to those who are far away from the polluting agent.

Acids↗
PubMed1980

Evaluation of the El Kholy technique for grouping beta-hemolytic streptococci.

One hundred and eleven strains of beta-hemolytic streptococci of human origin were grouped by the new nitrous acid procedure described by El Kholy et al. The results were comparable to the grouping obtained by the classical Lancefield hot-hydrochloric acid method. The El Kholy technique is simple and economic and is shown to be as sensitive and specific as the Lancefield procedure. We recommend the new method for routine use in the clinical laboratory and in studies on the prevalence of Streptococcus pyogenes in a developing country such as Brazil.

Humans↗
PubMed2000

Acid/pepsin promotion of carcinogenesis in the hamster cheek pouch.

OBJECTIVE: While clinical observation has suggested an association between gastroesophageal reflux and laryngeal carcinoma, the nature of this relationship has yet to be defined. The purpose of this study is to determine the carcinogenic potential of acid and pepsin mixtures in the hamster cheek pouch animal model. DESIGN: A blinded intervention study. SUBJECTS: One hundred male Syrian hamsters aged approximately 5 weeks. INTERVENTIONS: A control group of 20 hamsters received application of the carcinogen 9,10-dimethyl-1,2-henzanthracene (DMBA) to their cheek pouch mucosa. One experimental group (n = 20) received applications of DMBA plus hydrochloric acid, and another (n = 20) received DMBA plus an acid and pepsin solution. Latency to squamous cell tumor production, size of tumors, and numbers of tumors were compared among groups. RESULTS: Latency to tumor production and size of tumor were similar among groups, with both experimental and control groups developing tumors of comparable size after 12 weeks of chemical application. However, the number of tumors produced was significantly higher in the DMBA/acid and DMBA/acid/ pepsin groups than in the DMBA only group at 18 weeks, with 23, 27, and 10 tumors in these groups, respectively (P<.02). Likewise, a cumulative dysplasia score was different among groups at 18 weeks with the DMBA/acid and DMBA/acid/pepsin groups scoring higher degrees of dysplasia than the DMBA only group. CONCLUSION: These results suggest that application of acid and acid/pepsin mixtures may promote experimental carcinogenesis in the hamster cheek pouch.

Animals↗
PubMed2000

The rate at which human sperm are immobilized and killed by mild acidity.

OBJECTIVE: To determine the rate at which mild acidity immobilizes and kills human sperm and to evaluate an acidic microbicide, BufferGel, for sperm immobilization. DESIGN: Controlled in vitro study. SETTING: An academic research university and hospital andrology lab. PATIENT(S): Eight volunteer male sperm donors. INTERVENTION(S): Semen samples were treated with hydrochloric acid (HCl) or BufferGel. MAIN OUTCOME MEASURE(S): Sperm motility was measured by using a computerized automated semen analyzer and video microscopy. Sperm membrane permeability and intracellular pH were measured by using fluorescent techniques. RESULT(S): In semen acidified with HCl to pH 4.0, sperm were rapidly immobilized (within 1 min) and were irreversibly immobilized (killed) within 10 minutes. The speed of immobilization and of killing were both linearly proportional to hydrogen ion activity over a pH range of 7.5-4.0. Across the same range, the intracellular pH of human sperm equilibrated to within 0.5 pH units of extracellular pH within 1-2 minutes. BufferGel immobilized sperm significantly faster than HCl from pH 4.0-6.0. CONCLUSION(S): Exposure to mild acidity rapidly acidifies the intracellular pH of human sperm and is rapidly spermicidal. BufferGel accelerates acid immobilization of sperm.

Acids↗
PubMed2000

Symptom severity and oesophageal chemosensitivity to acid in older and young patients with gastro-oesophageal reflux.

INTRODUCTION: elderly patients appear to have a more aggressive form of gastro-oesophageal reflux disease than younger patients. Reduced pain perception with age is a possible underlying mechanism. AIMS: to compare the extent of oesophageal mucosal injury, acid exposure, symptom severity and perception thresholds for acid infusion in older (aged 60 or older) and younger patients with gastro-oesophageal reflux. METHODS: twenty-five younger and 23 older patients completed the study. We determined acid exposure and oesophageal mucosal injury by ambulatory 24-h oesophageal pH monitoring and upper endoscopy, respectively. We determined chemosensitivity by infusing 0.1 N hydrochloric acid into the mid-oesophagus for 10 min at 10 ml/min after a 2-min infusion of normal saline at a similar rate. We quantified acid perception thresholds by the lag time to initial typical symptom perception, intensity rating at the end of acid infusion and an acid perfusion sensitivity score, calculated from the fractional duration of symptom perception and intensity rating. RESULTS: mean percentage of total time with pH <4 was higher in the older (15.8+/-2.4) than in the younger patients (11.9+/-1.8; P = 0.18). Of the older group, 74% had erosive oesophagitis versus 64% in the younger group. Frequency of symptoms (heartburn, acid regurgitation and dysphagia) was lower in the elderly group. Older patients perceived heartburn and acid regurgitation as much less severe than younger patients (P < 0.05).Younger patients had a significantly shorter lag time to initial symptom perception (P < 0.05) and a higher sensory intensity rating (P < 0.08). The acid perfusion sensitivity score was significantly lower in the older group (P < 0.05). CONCLUSIONS: older patients with gastro-oesophageal reflux disease have reduced symptom severity for heartburn despite a tendency towards increased severity of oesophageal mucosal injury and acid exposure. Age-related reduction in chemosensitivity to acid is a possible underlying mechanism.

Adult↗
PubMed2006

[The comparison of the enzymatic and the acid hydrolyse at the toxicological screening of the small amount of urine].

The article deals with the toxicological screening directed at the identification and confirmation of the acid, neutral and basic medicaments and drugs in the urine. The efficiency of the hydrolysation using beta-glukuronidase (enzymatic hydrolyses) and using 0.1M hydrochloric acid (acid hydrolyses) from 2 ml of the urine were compared. The solid phase extraction (SPE) and the GC-MS identification were used. The efficiency of the extraction of paracetamol, buprenorphine and morphine is better by means of the enzymatic hydrolyses. Vice-versa the acid hydrolyses appears to be more applicable for benzodiazepines. The acid hydrolyses is faster and cheaper and the extracts contain less of the ballast materials.

Chemistry Techniques, Analytical↗
PubMed1995

Use of the bioluminescent bacterium Vibrio harveyi to detect biohazardous chemicals in soil and water extractions with and without acid.

An investigation was undertaken using the bioluminescence-reduction bioassay of Vibrio harveyi to study the toxicity of 31 chemicals in a soil and water extraction that was treated with and without hydrochloric acid. Soil had the chemical added and was washed with 0.2 N HC1 and afterward this acid-treated soil containing the chemical was evaluated. Each chemical was tested independently. Endpoints determined were either an estimated effective concentration at 50 or 20%, which was based on bacterial-luminescence remaining after treatment. This investigation suggests that metals are more effectively bound in treatments without acid than those with acid, while no difference in toxicity was observed for organics. In comparison to a previous study of toxicity using these chemicals in water, soil was effective in reducing toxicity as determined by this assay. However, each chemical appears to have its own unique toxicity characteristic when evaluated under different conditions.

Biodegradation, Environmental↗
PubMed1972

Gastric acid barrier to ingested microorganisms in man: studies in vivo and in vitro.

Reassessment of the ;gastric bactericidal barrier' to enteric bacteria in man included studies of the bactericidal activity of (1) the normal and achlorhydric stomach in vivo and (2) normal and achlorhydric gastric juice and other media in vitro. Within 30 minutes virtually all bacteria (Serratia marcescens) were eliminated in the normal stomach whereas no reduction occurred in the achlorhydric stomach in one hour. In vitro, identical bactericidal activity was observed at the same pH (from 2.0 to 7.0) in normal gastric juice, achlorhydric gastric juice, aqueous HCl, and nutrient broth. At pH less than 4.0, 99.9% of the bacteria were killed within 30 minutes. The presence of profuse bacterial flora, including coliforms, found in markedly acid-deficient but not in normal stomachs, correlates well with the absence of bactericidal activity. Thus, the ;gastric bactericidal barrier' is primarily pH-hydrochloric acid dependent, with other constituents of gastric juice contributing little, if any, detectable effect on the destruction of microorganisms.

Achlorhydria↗
PubMed2004

Expression and localization of c-Fos and NOS in the central nerve system following esophageal acid stimulation in rats.

AIM: To determine the distribution of neurons expressing c-Fos and nitric oxide synthase (NOS) in the central nerve system (CNS) following esophageal acid exposure, and to investigate the relationship between c-Fos and NOS. METHODS: Twelve Wistar rats were randomly divided into two equal groups. Hydrochloric acid with pepsin was perfused in the lower part of the esophagus for 60 min. As a control, normal saline was used. Thirty minutes after the perfusion, the rats were killed and brains were removed and processed for c-Fos immunohistochemistry and NADPH-d histochemistry. Blood pressure (BP), heart rate (HR), and respiratory rate (RR) during the experimental procedures were recorded every 10 min. RESULTS: There were no significant differences in BP, HR and RR between the two groups. c-Fos immunoreactivity was significantly increased in rats receiving acid plus pepsin perfusion in amygdala (AM), paraventricular nucleus (PVN), parabrachial nucleus (PBN), nucleus tractus solitarius and dorsal motor nucleus of vagus (NTS/DMV), nucleus ambiguous (NA), reticular nucleus of medulla (RNM) and area postrema (AP). NOS reactivity in this group was significantly increased in PVN, PBN, NTS/DMV, RNM and AP. c-Fos and NOS had significant correlation between PVN, PBN, NTS/DMV, RNM and AP. CONCLUSION: Acid plus pepsin perfusion of the esophagus results in neural activation in areas of CNS, and NO is likely one of the neurotransmitters in some of these areas.

Animals↗
PubMed1975

[Effect of acid extraction of basic proteins on the binding of acridine orange by cell chromatin].

The binding of acridine orange to chromatin of fixed human lymphocytes is increased after stepwise removal of histones by hydrochloric acid. No changes in the dye-binding features of the cells were found after f1 histone extraction (0.01 N HC1). Additional extraction of f2 and f3 by 0.05 N HC1 (partial extraction) and by 0.25 N HC1 (more complete extraction) resulted in increased binding of acridine orange (1.9 and 2.5 of that of the control, respectively).9222

Acridines↗
PubMed1989

The effects of extracellular acidosis on neurons and glia in vitro.

Cerebral lactic acid, a product of ischemic anaerobic glycolysis, may directly contribute to ischemic brain damage in vivo. In this study we evaluated the effects of extracellular acid exposure on 7-day-old cultures of embryonic rat forebrain. Mixed neuronal and glial cultures were exposed to either lactic or hydrochloric acid to compare the toxicities of relatively permeable and impermeable acids. Neurons were relatively resistant to extra-cellular HCl acidosis, often surviving 10-min exposures to pH 3.8. In the same cultures, immunochemically defined astrocytes survived 10-min HCl exposures to a maximum acidity of pH 4.2. Similarly, axonal bundles defasciculated in HCl-titrated media below pH 4.4, although their constituent fibers often survived pH 3.8. Cell death occurred at higher pH in cultures subjected to lactic acidosis than in those exposed to HCl. Over half of forebrain neurons and glia subjected for 10 min to lactic acidification failed to survive exposure to pH 4.9. Longer 1-h lactic acid incubations resulted in cell death below pH 5.2. The potent cytotoxicity of lactic acid may be a direct result of the relatively rapid transfer of its neutral protonated form across cell membranes. This process would rapidly deplete intracellular buffer stores, resulting in unchecked cytosolic acidification. Neuronal and glial death from extracellular acidosis may therefore be a function of both the degree and the rapidity of intracellular acidification.

Acidosis↗
PubMed2004

Elastase inhibition reduced death associated with acid aspiration-induced lung injury in hamsters.

This study examined whether the specific inhibition of neutrophil elastase by sivelestat sodium hydrate (sivelestat) reduced deaths associated with severe acute lung injury after hydrochloric acid (HCl) aspiration in hamsters. Animals that received a single intratracheal instillation of HCl (0.2 N, 200 microL) time-dependently died by occlusion of their trachea with inflammatory exudate. In a time course study, these animals developed severe lung injury, peaking 12 to 24 h after HCl instillation, as indicated by hemorrhage and a massive increase in the protein concentration of bronchoalveolar lavage fluid. These changes were closely correlated with neutrophil elastase activity in bronchoalveolar lavage fluid. Sivelestat (0.01, 0.1 and 1 mg/kg/h), when intravenously infused during the first 48 h post-HCl instillation, dose-dependently reduced death in HCl-instilled hamsters. In a separate experiment, analysis of bronchoalveolar lavage fluid parameters and partial pressure of arterial oxygen (PaO(2)) 8 h post-HCl instillation showed that sivelestat at 1 mg/kg/h, i.v. significantly improved both bronchoalveolar lavage fluid parameters and PaO(2) levels with evidence of the inhibition of neutrophil elastase activity in bronchoalveolar lavage fluid. These results suggest that neutrophil elastase plays a significant role in this type of severe acute lung injury that leads to death by respiratory failure.

Animals↗
PubMed1998

Heterogeneity of phenotypic and genotypic traits including organic-acid resistance in Escherichia coli O157 isolates.

We undertook an epidemiologic study for the sensitivity of both Shiga-like toxin (Slt)-producing Escherichia coli (STEC) O157 and non-STEC O157 strains isolated from different patients with diarrhea to hydrochloric acid (HCl) and organic acids such as acetate, propionate, butyrate and lactate, and other pathogenic factors. The E. coli O157 isolates examined showed a wide variety of organic-acid susceptibility patterns. E. coli O157 isolates resistant to HCl or acetate were found more frequently than those resistant to other organic acids. These isolates also showed diverse pathogenicity patterns for the presence of the virulence genes, antibiotic susceptibility and plasmid profile.

Acids, Acyclic↗
PubMed1993

Determination of inorganic arsenic and its organic metabolites in urine by flow-injection hydride generation atomic absorption spectrometry.

A method has been developed for the determination of inorganic arsenic [As(III) and As(V)] and its organic metabolites (monomethylarsenic and dimethylarsenic) in urine by flow-injection hydride generation atomic absorption spectrometry. The nontoxic seafood-derived arsenobetaine and arsenocholine species were first separated by a solid-phase extraction procedure. The remaining sample was digested with a mixture of nitric and sulfuric acids and potassium dichromate, followed by attack with hydrogen peroxide. The resulting As(V) was reduced to As(III) with potassium iodide in hydrochloric acid before injection into the flow-injection manifold. The percentage analytical recoveries (mean +/- 95% confidence interval) of various arsenic species added to a urine specimen at 250 micrograms/L were 108 +/- 2, 112 +/- 11, 104 +/- 7, and 95 +/- 5 for As(III), As(V), monomethylarsenic, and dimethylarsenic, respectively. For the determination of arsenic in Standard Reference Material 2670 (toxic metals in human urine), results agreed with the certified value (480 +/- 100 micrograms/L). Analyses of samples for the Centre de Toxicologie du Quebec, containing seafood-derived species, demonstrated the viability of the separation procedure. Detection limits were between 0.1 and 0.2 microgram/L in the solution injected into the manifold, and precision at 10 micrograms/L was between 2% and 3% (CV). These preliminary results show that the method might be applicable to determinations of arsenic in a range of clinical urine specimens.

Arsenic↗
PubMed2001

Dehydration of hydroxenin monoacetate in the presence of ultrasound.

Starting from hydroxenin monoacetate, vitamin A acetate is obtained in a E/Z mixture by dehydration. This result could be explained by the formation of a small amount of hydrochloric acid from trichloromethane under ultrasound irradiation and based on further experiments.

Hydrochloric Acid↗
PubMed1973

An analysis of hamster afferent taste nerve response functions.

Sensitivities to moderately intense stimuli representing four taste qualities to man were determined for 79 hamster chorda tympani fibers. Some fibers were very sensitive to sucrose, sodium chloride, or hydrochloric acid, but none were very sensitive to quinine. These sensitivities were not randomly distributed among fibers: the sucrose sensitivity was separated from and negatively correlated with the other sensitivities which were associated and positively correlated with each other. Moreover, there were a limited number of sensitivity patterns: (a) fibers responding best to sucrose responded second-best to salt, less to acid, not to quinine; (b) fibers responding best to salt either responded second-best to sucrose and not to acid or quinine; or second-best to acid, less to quinine, and not to sucrose; and (c) fibers responding best to acid responded second-best to salt, more to quinine, and less to sucrose than other fibers. Therefore, if four stimuli of different taste qualities are ordered from acceptable to unacceptable, neural response functions of most hamster chorda tympani taste fibers peak at one point. Sensitivities to nine other moderately intense stimuli which vary in quality to man were also determined for 46-49 of the fibers. Sensitivities to sweet stimuli were always associated with each other and separated from sensitivities to nonsweet stimuli. Sensitivities to nonsweet stimuli were all associated with each other; however, the strongest correlations were between sensitivities to stimuli of like quality, e.g., the three acids or the two sodium salts.

Animals↗
PubMed1987

Use of histological samples for assessing skeletal calcium.

Bone samples were decalcified using 5% formic acid. Their calcium content was then quantified by analysing the calcium extracted in the decalcification solution. This was correlated with matched samples digested in hydrochloric acid. No significant differences were found. This indicates that bone biopsy specimens taken for histological analysis can be used for the direct assessment of skeletal calcium. The method can therefore simplify investigations into metabolic bone diseases and provide a direct correlation between skeletal calcium and bone histology.

Animals↗