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PubMed1991

Route of access of secretin into rabbit duodenal lumen during acid perfusion.

The route of entry of immunoreactive secretin into the duodenal lumen during acid perfusion is unknown. Possible sites include paracellular diffusion from the extracellular space, transapical secretion from S cells, or leaching from cells damaged by the perfusate. Antisecretin in the extracellular space and interstitium should reduce access due to paracellular diffusion from the interstitium without significantly affecting secretion or leaching. We therefore studied the effect of intravenous antisecretin antibody on luminal secretin output. Two groups of rabbits received either intravenous normal rabbit serum (controls) or antisecretin antibody, before perfusing a closed segment of duodenum with hydrochloric acid. Preliminary experiments established that duodenal perfusion with HCl concentrations below 0.025N produced no apparent mucosal damage on electron microscopy. HCl concentrations above this significantly damaged the mucosa. In the control group, perfusion with 0.01N, 0.0125N, and 0.025N hydrochloric acid resulted in a dose-dependent increase in secretin in the perfusate. Secretin output was markedly reduced in the group injected with secretin antibody. Antisecretin antibody significantly reduced bile flow at all levels of HCl concentration in the duodenal perfusate. These data suggest that luminal secretin is probably derived from the interstitium and travels to the lumen across narrow paracellular channels.

Animals↗
PubMed1992

A separating method for quantifying mucus glycoprotein localized in the different layer of rat gastric mucosa.

A method was devised for separating rat gastric mucosa into three layers each containing a different mucin species. The mucus gel (first layer) was removed by stirring the gastric mucosa in a solution of phosphate-buffered saline containing 2% N-acetylcysteine. The surface mucosa (second layer), rich in surface mucus cells, was then separated from the deep mucosa (third layer) containing mucus neck cells, by scraping with forceps. The effectiveness of this method was confirmed by light microscopical observation after GOCTS-PCS (dual staining by the galactose oxidase-cold thionin Schiff method and paradoxical concanavalin A method) and AB-PAS staining (dual staining with alcian blue and the periodic acid Schiff method). The fixed specimen of scraped mucus and cell debris was rich in AB-PAS and GOCTS positive mucus, but was hardly stained by PCS, indicating mucus derived from surface mucus cells to have been efficiently recovered from this preparation. The residual mucosa could be stained by PCS but hardly at all by AB-PAS or GOCTS. The lyophilized powder specimens obtained from the three different layers of rat gastric mucosa were used to extract and quantify mucus glycoprotein (mucin). This was done to examine changes in mucin content in the three layers of gastric mucosa one hour following the oral administration of 20% ethanol or 0.35 N hydrochloric acid, both mild irritants. Mucin content was noted to significantly increase in the first layer but hardly at all in the second layer. In the third layer, it decreased significantly by 0.35 N hydrochloric acid, but changed only slightly by 20% ethanol administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Liquid-liquid systems for acid hydrolysis of glycoalkaloids from Solanum tuberosum L. tuber sprouts and solanidine extraction.

BACKGROUND: Potato sprouts (Solanum tuberosum L.) contain steroidal glycoalkaloids containing solanidine, an important precursor for hormone synthesis. Glycoalkaloids are reported to inactivate the Herpes simplex, Herpes zoster and Herpes genitalis viruses in humans, while Aglyones, including solasodine, may protect against skin cancer. Extracts of glycoalkaloids or solanidine can be used to obtain a potential skin cancer preparation for clinical research. MATERIAL/METHODS: Dried potato sprouts were used to obtain glycoalkaloids and solanidine. The hydrolysis of glycoalkaloids in a liquid-liquid system was performed using a reflux condenser, obtaining extracts of glycolakaloids from dried and milled potato tuber sprouts. Hydrochloric acid was then added to the extract to form the first (aqueous) phase, and chloroform, trichloroethylene or carbon tetrachloride to form the second (organic) phase of the liquid-liquid system. In this way, glycoalkaloid hydrolysis to solanidine and solanidine extraction in the organic liquid phase were combined into a single step. IR and GC/MS analysis of solanidine was also conducted. RESULTS: Based on the results we obtained, the optimal liquid-liquid system was found to be 2% w/v hydrochloric acid in a 50% (volume) methanolic extract of glycoalkaloids from tuber sprouts, as the first phase, and chloroform as the second phase. Using this system, a yield of 1.46 g solanidine per 100 g of dried potato sprouts can be achieved. CONCLUSIONS: Glycoalkaloid hydrolysis in a liquid-liquid system yields the aglycone solanidine can be obtained from dried potato sprouts. The yield of solanidine is higher than that obtained using solid-liquid-liquid systems for glycoalkaloid hydrolysis from potato vines.

Chloroform↗
PubMed1976

Effects of lesions of the gustatory necortex on taste aversion learning in the rat.

Normal rats and rats with lesions of the gustatory neocortex (GN) were compared for their ability to learn aversions to taste cues paired with toxicosis. When the taste presentation was followed immediately by toxicosis, normal rats and rats with lesions of the posterior (visual) neocortex learned aversions to sucrose, sodium chloride, quinine hydrochloride, and hydrochloric acid solutions. Rats with GN lesions learned aversions to all solutions except sucrose. In preference tests, all solutions were shown to be discriminable from water by both normal rats and rats with GN lesions. Under conditions in which a 6-hr delay separated taste presentation and toxicosis, normal rats again learned specific aversions to all four solutions, but rats with GN lesions failed to learn specific aversions to sucrose, sodium chloride, and hydrochloric acid solutions. It was shown that the ability of rats with GN lesions to learn aversions to sucrose and quinine depended on stimulus concentration; and it was proposed that the data could be accounted for by postulating a change in the threshold for taste-illness associations following GN lesions.

Animals↗
PubMed1970

Separation of antigens by immunological specificity. Studies on the desorption of homologous antigen from disulphide-linked antibody immunosorbents.

1. Glycine-hydrochloric acid buffer, pH2.2, desorbed (131)I-labelled human serum albumin (100%), lysozyme (100%), ovalbumin (90%), fluorescent ovalbumin (50-60%) and fluorescent human gamma-globulin (20%) from their respective homologous disulphide-linked antibody immunosorbents; reasons are suggested for the low recoveries of the fluorescently labelled proteins. 2. Approx. 40% of the recovered (131)I-labelled human serum albumin and fluorescent ovalbumin was desorbed above pH6.0, but lysozyme was not eluted until the pH was 3.0 or below. 3. In all cases where high recoveries of antigen were obtained, the immunosorbents could be regenerated and recycled at least four times with full retention of specificity and minimal diminution of capacity. 4. The desorbed antigens were unchanged when compared with the original antigens by quantitative precipitin, specificradioactivity, fluorescent and enzymic analyses and by cellulose acetate electrophoresis. 5. Desorption of antigen with a variety of reagents was investigated. These reagents were less satisfactory than glycine-hydrochloric acid.

Antigen-Antibody Reactions↗
PubMed1983

Glycosaminoglycans: their distribution and potential vasoactive action in the nonpregnant and pregnant ovine uterus.

The effects of direct uterine artery infusions of glucosamine-hydrochloric acid, dextrose, and mannitol were evaluated in ewes that had undergone oophorectomy. Glucosamine-hydrochloric acid caused a prompt dose-related increase in uterine blood flow which approximated uterine blood flow rates induced by estradiol. Infusions of dextrose caused similar but transient vasodilatation, whereas infusions of mannitol had no effect. The glycosaminoglycans content of endometrium, myometrium, and caruncles/cotyledons (placentomes) was measured in nonpregnant and early pregnant ewes between 19 and 45 days' gestation. In endometrium and myometrium, total hexosamine levels were similar in nonpregnant and pregnant ewes. In the placentomes, total hexosamine levels increased steadily after 20 to 25 days' gestation. The hyaluronic acid fraction of total glycosaminoglycans hexosamine increased similarly and paralleled the total hexosamine levels. Galactosamine levels were unchanged in all tissues. It is postulated that a function of Wharton's jelly may be to provide the mechanism for shunting of uterine blood flow to the ovine placentomes.

Animals↗
PubMed1965

THE RESPIRATION OF ISOLATED RAT-HEPATIC CELLS IN SUSPENSION.

1. Rat-hepatic cells in suspension have been shown to have an endogenous respiration of 5.6+/-0.17 when suspended in 0.1 m-sucrose and 0.02 m-tris-hydrochloric acid buffer. The respiration in 0.25 m-sucrose and 0.02 m-tris-hydrochloric acid buffer is 30-40% less. 2. Potassium chloride (0.05 m) is slightly inhibitory and calcium chloride (0.0025 m) highly inhibitory to endogenous respiration of the hepatic cells in suspension. The cells do not respire in Krebs-Ringer phosphate buffer. 3. The respiration of the hepatic cells in suspension is stimulated by pyruvate, citrate, isocitrate, oxoglutarate, succinate, fumarate, malate and glutamate; there is no significant stimulation (or inhibition) by glucose, fructose, acetate and butyrate. In almost all the cases where stimulation was observed, it was found that the higher the endogenous respiration the lower is the stimulation.

Acetates↗
PubMed1995

The neutralizing capacity and sodium content of antacid brands on the Kenyan market.

Seventeen brands of antacid products available on the Kenya market were investigated for their acid neutralising capacity and sodium content. Thirteen tablet products gave neutralising capacity per tablet of between 4.7 to 14.12 mMol hydrochloric acid. The neutralising capacities for the suspensions ranged between 11.97 to 34.32 mMol hydrochloric acid for 10ml suspension. The lowest neutralising capacities were obtained for products based on compound magnesium trisilicate and higher capacities for those containing magaldrate, or magnesium hydroxide or magnesium carbonate in combination with other ingredients. The fastest rate of neutralization was obtained with preparations containing carbonates and the lowest by compound magnesium trisilicate. The sodium content for the preparations was between < 0.001 mEq to 0.732 mEq sodium per minimum recommended dose. The study shows a high degree of variation in both the acid neutralising capacities and the sodium content of the different brands investigated.

Antacids↗
PubMed1980

[Synthesis of antiproteolytically active 3,5-bis(4-amidinobenzyl)- and 3,5-bis(4-amidinobenzylidene)piperidone-(4) derivatives (author's transl)].

Because of the good inhibitory effects of some alpha, alpha'-bis (amidinobenzylidene)cycloalkanoes and of their hydrogenation products on serine proteinases, the authors prepared structurally analogous bisamidines of heterocycloalkanones. To obtain 3,5-bis(4-amidinobenzyl)-N-benzoylpiperidone-(4), N-benzoylpiperidone-(4) was condensed with 4-cyanobenzaldehyde in concentrated phosphoric acid. The resultant 3,5-bis(4-cyanobenzylidene)-N-benzoylpiperidone-(4) was reduced with zinc-glacial acetic acid, and the reduction product was converted into the respective bisamidine by means of the Pinner method. 3-(4-Cyanobenzylidene)-5-(4-aminocarbonylbenzylidene)-N-benzoylpiperidone-(4) was isolated as a by-product of the condensation of N-benzoylpiperidone-(4) with 4-cyanobenzaldehyde. To prepare 3,5-bis(4-amidinobenzylidene)-N-benzoylpiperidone-(4), N-benzoylpiperidone-(4) was condensed with 4-amidinobenzaldehyde hydrochloride in concentrated phosphoric acid. The resultant bis-dihydrogen phosphate was converted into the bis-hydrochloride by treatment with methanolic hydrochloric acid solution in the cold, and debenzoylated to 3,5-bis(4-amidinobenzylidene)piperidone-(4) trihydrochloride on heating with methanolic hydrochloric acid solution.

Amidines↗
PubMed2002

[Survival of Vibrio parahaemolyticus serovar O3:K6 strains under acidic conditions].

The survival of Vibrio parahaemolyticus serovar O3:K6 strains and other serovars in the presence of acetic, citric and hydrochloric acids were studied. There were no differences in resistance to these acids between serovar O3:K6 and the other serovars. At pH 5.6, citric acid was more effective in reducing the number of viable cells of V. parahaemolyticus than acetic acid. However, at pH 4.5, acetic acid was more effective than citric acid. The number of viable cells decreased quickly in the presence of rice vinegar or wine vinegar at pH 4.0.

Acetic Acid↗
PubMed1987

Ketone bodies increase glomerular filtration rate in normal man and in patients with type 1 (insulin-dependent) diabetes mellitus.

The purpose of this study was to investigate whether the administration of acetoacetic and hydrochloric acids in a group of control and Type 1 (insulin-dependent) diabetic patients influenced renal haemodynamics. Renal plasma flow increased from 657 +/- 88 to 762 +/- 81 ml X min-1. 1.73 m-2 in diabetic patients (p less than 0.01) and from 590 +/- 71 to 691 +/- 135 in control subjects (p less than 0.01). Glomerular filtration rate increased from 135 +/- 9 to 180 +/- 8 ml X min-1. 1.73 m-2 in diabetic patients (p less than 0.001) and from 117 +/- 8 to 145 +/- 7 in control subjects (p less than 0.01). Similar effects on renal haemodynamics, even if less pronounced, were observed with low dose acetoacetic but not with hydrochloric acid infusion. Total protein, beta 2-microglobulin but not albumin excretion rates were increased by acetoacetic acid. We conclude that an acute increase in blood concentration of ketone bodies within the range found in diabetic patients with poor metabolic control increases renal plasma flow and glomerular filtration rate both in control subjects and diabetic patients and causes a tubular proteinuria.

Acetoacetates↗
PubMed1991

Determination of gadolinium in biological materials using graphite furnace atomic absorption spectrometry with a tantalum boat after solvent extraction.

A method was developed for the determination of gadolinium (Gd) in biological material using graphite furnace atomic absorption spectrometry (GFAAS). The element is first extracted into methyl isobutyl ketone and then reextracted into hydrochloric acid. Factors influencing the recovery of extraction such as pH, choice of chelating agents, and hydrochloric acid concentration have been investigated. The element is determined under STPF (stabilized temperature platform furnace) conditions with atomization from a tantalum boat. Under optimized furnace conditions, the use of the tantalum boat improved sensitivity substantially compared to the use of pyrolytically coated graphite tubes. Around 150 measurements could be performed with 1 boat. Memory effects, being a common problem in the GFAAS determination of lanthanoids, were no longer observed after insertion of the boat. The characteristic mass and detection limit (2SD; SD = standard deviation) of the Gd determination are 1000 and 2060 pg, respectively. The precision evaluated as the relative standard deviation (RSD) of six analyses was below 10% for tissue Gd concentrations ranging from 0.92 to 72.0 micrograms g-1. The recovery of added analyte ranged between 92.0% and 99.3%. The method was found to be suitable for studying the pharmacokinetics and biodistribution of Gd in rats.

Animals↗
PubMed2005

Pulmonary aspiration: new therapeutic approaches in the experimental model.

BACKGROUND: Acute lung injury caused by gastric aspiration is a frequent occurrence in unconscious patients. Acute respiratory distress syndrome in association with gastric aspiration carries a mortality of up to 30% and accounts for up to 20% of deaths associated with anesthesia. Although the clinical condition is well known, knowledge about the exact inflammatory mechanisms is still incomplete. This study was performed to define the role of alveolar macrophages in this inflammatory response. In addition, potentially modifying effects of intratracheally applied nuclear factor kappaB inhibitor pyrrolidine dithiocarbamate were investigated. METHODS: Rat alveolar macrophages were depleted by intratracheal administration of clodronate liposomes, and lung injury was evaluated 6 h after instillation of 0.1N hydrochloric acid. In a second set of experiments, pyrrolidine dithiocarbamate was intratracheally instilled 3 h after hydrochloric acid application, and injury parameters were determined. RESULTS: Depletion of alveolar macrophages resulted in decreased production of inflammatory mediators in acid aspiration (23-80% reduction of messenger RNA or protein of inflammatory mediators; P < 0.05) and consequently also in diminished neutrophil recruitment (36% fewer neutrophils; P < 0.01). Treatment with pyrrolidine dithiocarbamate was highly effective in decreasing neutrophil recruitment (66%; P < 0.01) and vascular permeability (80%; P < 0.001). CONCLUSIONS: These data suggest that alveolar macrophages play an essential role in the inflammatory response of acid-induced lung injury. For the first time, attenuation of acid-induced lung injury with an inhibitor, applied after the onset of injury, is shown.

Animals↗
PubMed1980

Simultaneous partitioning and hydrolysis kinetics of amoxicillin and ampicillin.

The kinetics of ampicillin and amoxicillin partitioning with simultaneous acid-catalyzed hydrolysis were studied in a stirred transfer cell containing isobutanol as the extract and aqueous hydrochloric acid (0.1-0.5 N) as the raffinate at 37 degrees. Biexponential data for the concentration in both the raffinate (C1) and the extract (C2) as a function of time were analyzed simultaneously by nonlinear regression to estimate the apparent first-order rate constant for transfer from hydrochloric acid to isobutanol (k '12), the reverse transfer constant (k '21), and the hydrolysis rate constant (k). Agreement between k values determined in the presence of simultaneous partitioning and those determined in the absence of partitioning (k app) verified the nonlinear estimates. Apparent partition coefficients, which represent the values that would be obtained in the absence of hydrolysis K'D = C1 infinity/C2 infinity), were estimated from K'D = k'12/k'21. During terminal monoexponential loss, where C1 approximately equal to Y'e-beta t and C2 approximately equal to Z'e-beta t, the kinetically controlled C2/C1 ratio (r) is described by [K'12/K'21-beta)], which decreases with decreasing kappa values until r approaches K'D. The difference between the terminal concentration ratio, r, and its corresponding partition coefficient, K'D, is a measure of the degree to which kinetic processes control distribution. Both ampicillin and amoxicillin showed kinetic control of the distribution ratios in 0.5 N HCl, where the hydrolysis rate constant was significant relative to the distribution rate constants. Ampicillin had r approximately equal to 1.74 and K'D approximately equal to 0.92; amoxicillin had r approximately equal to 0.95 and K'D approximately equal to 0.65. As the (K'12 + K'21/k ratio increased, the r values approached K'D so that in 0.1 N HCl, r approximately K'D = 0.33 for amoxicillin and r approximately 0.6 and K'D approximately 0.56 for ampicillin. In general, amoxicillin distribution rate constants (K'12 + K'21) were roughly twice those of ampicillin, whereas ampicillin K'D and r values were nearly double those of amoxicillin. Thus, the kinetic and thermodynamic rank orders are opposite. This result may have implications in drug design via molecular modification.

Amoxicillin↗
PubMed2001

Chemical method for determination of carbon dioxide content in egg yolk and egg albumen.

The safety, quality, and shelf life of shell eggs is a function of carbon dioxide content. A commercial process was recently developed for rapidly cooling shell eggs by using cryogenic CO2. The benefit of this new process over existing cooling processes is that the CO2 addition during cryogenic cooling provides additional safety and quality enhancements. In order for these benefits to be fully developed into a process that can be adopted by the egg industry, and thus realized by the consumer, the amount of CO2 absorbed by the egg during this process needs to be quantified. Because the albumen pH of rapidly cooled eggs was reduced to pH <6.5, existing titrametric methods were not adequate for determining CO2 content. They did not prevent CO2 loss during neutralization. A simple and accurate method for determining CO2 content in acidified egg albumen and yolk samples was developed. This method involves the liberation of CO2 from an acidified egg sample into a standardized, dilute sodium hydroxide solution inside a sealed jar. The egg sample and a small beaker containing the standardized sodium hydroxide solution are placed in a glass jar and sealed. Next, a concentrated acid phosphate solution is injected through a rubber septum in the cap of the jar onto the egg sample, while avoiding contact with the sodium hydroxide solution. The sample is then stored at 37 C for 24 h. During this storage period, the carbon dioxide is released from the egg sample and is absorbed into the sodium hydroxide solution. Afterwards, the dilute sodium hydroxide solution is removed and titrated to the phenolphthalein endpoint using a dilute, standardized hydrochloric acid solution. The amount of hydrochloric acid solution required for neutralization can be directly related to CO2 content in the sample.

Animals↗
PubMed1976

[Studies of the methods used for the determination of the digestibility of crude fats in calves].

An investigation was made of methods used for the exact determination of the crude content and crude extract of faeces. The following methods were examined: (1) Following treatment with hydrochloric acid a 1:1 mixture of ether and petroleum ether was used. (2) Following hydrolysis with hydrochloric acid extraction with ether was carried out immediately from the aqueous phases. (3) The analysis was carried out with Folch's solvent. A 1:1 mixture of methanol and chloroform was used. (4) The faeces were dried with infrared lamps and crude fat extraction was carried out with Folch's solvent. A 1:1 mixture of methanol and chloroform was used. (5) The faeces were dried with infrared lamps and extraction with ether was done in a Soxhlet apparatus. Nearly identical results were obtained with methods 1 and 2 or 3 and 4 in determining the content of crude extract, the acid number and the percentage proportion of fatty acids. Essential differences were found between methods 1 and 2 and methods 3 and 4. The most reliable results were obtained by using method (2). Method (5) was found to be most suitable for large-scale testing. Values for the content of crude extract in the faeces were somewhat lower (0.78%-1.2%) when determined by method (5). These variations were not significant statistically. (P greater than 5%). No significant differences were observed between methods (2) and (5). It was thus established that method (5) is best suited for estimating the crude extract of the faces. The faeces of calves were found to contain a high proportion of unsaponifiable matter. This proportion was subtracted from the percentage of crude extract and the amount of faecal crude fat was thus estimated. Very small but statistically significant differences were found by converting digestibility data of crude extract into those of crude fat. Hence, for future work the most appropriate method appears to be the estimation of the crude extract in feedingstuffs.

Animals↗
PubMed2004

Alternative quality control for technetium-99m IDA complexes.

A quality control procedure for 99mTc-IDA complexes based on the use of C18 Sep-pak cartridges is developed and the validation of the procedure presented. C18 Sep-pak cartridges are pretreated by washing with 95% ethanol followed by 10(-3) N hydrochloric acid. A small amount of the 99mTc-IDA complex is applied, washed with 10(-3) N hydrochloric acid and eluted with 95% ethanol. The radiochemical purity values obtained for 99mTc-mebrofenin and 99mTc-disofenin using this Sep-pak procedure are comparable to those obtained using the standard two strip (ITLC-SG/100% methanol, ITLC-SA/20% saline) procedure.

Chromatography, Thin Layer↗
PubMed2006

Newly synthesized tetraoxa-diaza crown ether derivatives versus commercialized crown ethers in the separation of positional isomers with capillary electrophoresis.

Three new tetraoxa-diaza derivatives of 1,4,10,13-tetraoxa-7,16-diazacyclo-octadecane (R-1, R-2 and R-3) and three commercially available crown ethers, 18-crown-6 (18C6), (+)-18-crown-6-tetracarboxilic acid (18C6H4) and 1,4,10,13-tetraoxa-7,16-diazacyclo-octadecane, were investigated to separate the positional isomers of aminophenol, aminobenzoic acid and aminocresol. The running electrolyte, in which the crown ethers were dissolved, was a 50 mM Tris solution adjusted to pH 2.0 with hydrochloric acid. Using 50 mM H3PO4 buffer, whose pH was adjusted to 2.0 with Tris, or only hydrochloric acid solution with the same pH, did not allow good separations for the tested components. The effect of the crown ether concentration on the separation of the 11 positional isomers was studied in the concentration range of 10-50 mM. The best separations were achieved using the 18C6 and the 18C6H4 crown ethers: 9 isomers out of 11 could be separated within one run. The m- and p-aminophenol isomers could not be separated under the investigated experimental conditions. The newly synthesized tetraoxa-diaza crown ether derivatives were only found suitable for the separation of aminobenzoic acid positional isomers. The macrocyclic ring of the tetraoxa-diaza crown ethers was not able to form a stable inclusion complex with the tested positional isomers. Consequently, the aminophenol and aminocresol isomers were not separated, the isomers migrated with the same or very similar velocities.

Crown Ethers↗