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PubMed1981

[Focusing chromatography using a dilute precipitation reagent--separation of 226Ra decayed nuclides by potassium fluoride (author's transl)].

The electrophoresis of 226Ra and it's decayed nuclides was carried out by using hydrochloric acid in the positive electrode cell and aqueous solution of potassium fluoride in the negative electrode cell. Experimental factors, i.e. concentrations of potassium fluoride and hydrochloric acid, intensity of electric field, duration for electrophoresis and pH value of the potassium fluoride solution etc. were examined. The sample solution was of 0.01 M hydrochloric acid with a tracer amount of 226Ra and 210Pb. Each of these nuclides was carrier free and was 4GB1/l(1 muCi/ml) in concentration. For the sake of autoradiography, a photoengraving film (Fujilith Ortho Film, TAC = 135) was made use of examining the locations of the separated radioactive bands obtained on the paper strip. Their beta and gamma radioactivities were detected as the film darkening on developing the film. According to the positions thus detected, the strip filter paper was cut into pieces and the species of radionuclides were determined by the measurements of energies and half-lives on beta and gamma rays. The locations of the separated alpha-radionuclides were decided by etching the surface of it's film with 6 M aqueous solution of sodium hydroxide and the species of radionuclides were determined by the solid state alpha-track detection method. As the result, the optimum conditions for the separation are to use 0.01 M hydrochloric acid in the positive cell and 0.005 M potassium fluoride of pH 6.2 in the negative cell, intensity of the applied electric field being 1000 V/30 cm, and electrophoresis time being 20 minutes. The proposed method gave good results for focusing and separating the radium series nuclides. Bands of 210Bi and 210Po were found on the positive electrode side, while the bands of 226Ra and 210Pb (containing 214Pb) were on the negative electrode side.

Chemical Precipitation↗

PubMed1981

Structural deterioration of prosthetic oesophageal tubes: an in vitro comparison of latex rubber and silicone rubber tubes.

In a series of 100 patients with carcinoma of the oesophagus or cardia undergoing palliative intubation at endoscopy using a latex rubber or a silicone rubber tube 2 cases of tube fragmentation were encountered and are described. The effects of hydrochloric acid, bile and irradiation on the tubes have been studied in vitro. After incubation in hydrochloric acid (0.1 mol/l), the breaking force of latex rubber tubes fell by 31 per cent (48 N) (but did not change significantly for silicone rubber tubes. The addition of bile to the hydrochloric acid (0.1 mol/l) did not further influence the breaking force of either type of tube. Megavoltage irradiation with 7500 rad did not affect the breaking strength of silicone rubber tubes but caused a reduction of breaking strength of latex rubber tubes. These findings suggest that silicone rubber has advantages over latex rubber as a material for prosthetic oesophageal tubes.

Aged↗

PubMed1985

Are esophageal motility abnormalities produced during the intraesophageal acid perfusion test?

Many years ago, it was proposed that the symptoms of heartburn correlated more closely with acid-induced esophageal motility abnormalities than with the presence of inflammation. This concept, however, has not been evaluated by modern manometric techniques. We monitored intraesophageal pressures during acid perfusion (O.1N hydrochloric acid) in 17 reflux patients with gross esophagitis and positive pain response and 17 age-matched controls. Using a low-compliance infusion system, amplitude, duration, velocity, and the presence of simultaneous and repetitive contractions in the body of the esophagus were evaluated. Amplitude did not change in either group. Duration did increase significantly during acid perfusion in reflux patients, but not in controls. Mean duration between groups, however, was similar before and during acid perfusion. No simultaneous contractions were observed, while three patients and two controls had repetitive contractions. A significant decrease in velocity was observed in both groups during acid perfusion. These studies indicate that acid-induced motor abnormalities are neither a common accompaniment nor necessary for the production of acid-induced pain in the esophagus.

Adult↗

PubMed2006

Acidity induces c-Fos expression in a subpopulation of human colonic submucosal neurons.

Enteric neurons responding to chemical challenge of the mucosa have been characterized in animal models mainly in the myenteric plexus. However, in humans, the existence of enteric neurons responding to chemical stimulation of the mucosa remains currently unknown. Therefore, the aim of our study was to identify and characterize human submucosal neurons activated by mucosal challenge with butyrate or hydrochloric acid. Segments of human colon were placed in a modified Ussing chamber and incubated on the mucosal side with butyric acid (20 mM, pH 6.5), sodium butyrate (20 mM, pH 7.5), hydrochloric acid (10 mM, pH 6.5) or culture medium (pH 7.5). After 90 min of culture, tissues were fixed and microdissected to obtain whole mount preparation of submucosa containing the Meissner's plexus. Neuron specific enolase (NSE), c-Fos, vasoactive intestinal peptide (VIP) and substance P (SP) were detected using immunohistochemical methods. Tetrodotoxin (TTX, 1 microM) was used to inhibit neuronal activity. After 90 min of culture, butyric acid induced a significant 5.6-fold increase in the proportion of c-Fos-immunoreactive neurons compared to control (19 +/- 4% versus 4 +/- 1%, respectively, p < 0.001). 41 +/- 5% of c-Fos-immunoreactive neurons were VIP-immunoreactive and 3 +/- 2% were SP-immunoreactive. Butyric acid did not modify the proportion of VIP-immunoreactive neurons. The increase in c-Fos-immunoreactive neurons induced by butyric acid was reproduced with hydrochloric acid at the same pH but not with sodium butyrate. Finally, preincubation of the tissue with TTX prevented the effect of butyric acid. In conclusion, our results demonstrate that acidic mucosal challenge induced the activation of a population of human submucosal neurons with a specific neurochemical coding.

Butyrates↗

PubMed1977

[Study on the amide of 2-chlorobornan-4-carboxylic acid].

During the study of the transpositions undergone by the amide of canphen-4-carboxylic acid on treatment with concentrated hydrochloric acid, the formation of the amide of 2-chlorobornan-4-carboxylic acid alone, arising in two polymorphous forms, has been confirmed. Its reduction produced 2-chloro-4-aminomethylbornane; the detachment of hydrochloric acid at the amide of canphen-1-carboxylic acid.

Amides↗

PubMed2026

Proteomic characterization of the acquired enamel pellicle under acidic challenges at early and mature formation stages.

OBJECTIVES: This study aimed to characterize acquired enamel pellicle (AEP) proteomic changes after exposure to citric acid (CA) and hydrochloric acid (HCl) under different pellicle formation times (3 and 120 min) in the same volunteers. DESIGN: Nine healthy volunteers participated in this randomized crossover in vivo study. The AEP was allowed to form for 3 or 120 min and subsequently exposed for 10 s to deionized water (control), 1% CA (pH 2.5), or 0.01 M HCl (pH 2.0). Pellicle samples were collected, followed by protein extraction, tryptic digestion, and analysis by nanoliquid chromatography (nanoLC) coupled to mass spectrometry (MS) with MSE (data-independent acquisition; nanoLC-MSᴱ). Label-free quantitative proteomics were performed for relative quantification using t-test (p < 0.05). RESULTS: At 120 min, CA exposure markedly reduced several typical AEP proteins, especially acidic proline-rich proteins (PRPs). Conversely, basic PRPs were upregulated, suggesting acid-resistance protein signature. At 3 min, basal-layer proteins (PRPs, cystatins, histatins and mucins) were more abundant. Hemoglobins increased 6-8-fold (up to 150-fold in 3 min control), suggesting association with early pellicle formation and an acid-resistant protein signature. CA exposures for 120 min also upregulated typical AEP proteins (PRPs, mucins, cystatins, immunoglobulins), while HCl exposure depleted albumins and lactotransferrin. CONCLUSION: Intrinsic and extrinsic acids induce distinct proteomic signatures in the AEP. Hemoglobin and PRPs appear consistently enriched in the early pellicle layer, reflecting an initial acid-resistant protein signature. These findings provide new insights into the molecular remodeling of the AEP following intrinsic and extrinsic acid exposure, highlighting proteins potentially involved in early-stage pellicle formation.

Humans↗

PubMed2005

Effect of surface treatment on bond strength of low-fusing porcelain to commercially pure titanium.

STATEMENT OF PROBLEM: Due to the pronounced oxidative nature of titanium at high temperatures, an excessively thick layer of TiO(2) may form on the surface. This oxide layer could adversely affect titanium-porcelain bonding. PURPOSE: The purpose of this study was to investigate the effect of bonding agent and surface treatment using airborne-particle abrasion and hydrochloric acid on the bond strength between a low-fusing porcelain and commercially pure cast titanium. MATERIAL AND METHODS: A casting unit was used to cast 60 specimens of commercially pure titanium (25.0 x 3.0 x 0.5 mm). The specimens were equally divided into 3 groups. The first group received no surface treatment and served as the control, the second group was subjected to airborne-particle abrasion, and the third group was treated with hydrochloric acid. The specimens in each group were further divided into 2 subgroups of 10 each. Ten specimens were treated with bonding agent (Noritake), and 10 specimens were not treated with bonding agent. Low-fusing porcelain (Noritake) was fired onto the surface of the specimens. A universal testing machine was used to perform the 3-point bending test. The titanium-ceramic interfaces were subjected to scanning electron microscopic analysis. The bond failure data (MPa) were analyzed with a 2-way analysis of variance and Tukey multiple range tests (alpha=.05). Four specimens from each group were selected for scanning electron microscopic examination. RESULTS: The debonding test showed that surface treatment with airborne-particle abrasion followed by application of a bonding agent resulted in the strongest (35.60 +/- 8.15 MPa) titanium-ceramic bond (P<.001), followed by airborne-particle abrasion alone (25.6 +/- 5.4 MPa) and bonding agent alone (24.7 +/- 6.3 MPa). Hydrochloric acid surface treatment provided no beneficial effect to the titanium-ceramic bond strength compared to untreated specimens (P=.975). The photomicrographs of the titanium surface after debonding demonstrated residual porcelain retained on the metal surface for all groups. CONCLUSIONS: Surface treatment using either airborne-particle abrasion or bonding agent alone enhanced the bond strength of cast commercially pure titanium to low-fusing porcelain. The combination of airborne-particle abrasion and bonding agent provided the greatest improvement in titanium-ceramic bond strength. Titanium surface treatment with hydrochloric acid, with or without bonding agent, produced values that were not statistically different than the control.

Acid Etching, Dental↗

PubMed1981

Assessment of alveolar-capillary membrane permeability of dogs by aerosolization.

We developed a method for measuring an index of alveolar-capillary membrane permeability (PI) by aerosolizing a mixture of 99mTc-diethylenetriaminepentaacetic acid (Tc-DTPA) and 125I-antipyrine (I-AP) and injecting 111In-DTPA (In-DTPA). The I-AP was used to compute the quantity of Tc-DTPA delivered and the In-DTPA the quantity of Tc-DTPA in the body. The PI was the ratio of the uptake of Tc-DTPA per minute to the amount deposited at the end of aerosolization. In 14 anesthetized dogs we measured the volume of distribution of I-AP (0.54 +/- 0.034 l/kg body wt) and/or showed that the volumes of distribution of Tc-DTPA and In-DTPA were similar. We measured PI in four groups of dogs: control (n = 5), oleic acid (n = 5), hydrochloric acid (n = 6), and high left atrial pressure (n = 5). The PI increased significantly in both groups with acid-induced increased permeability compared with the control and high left atrial pressure groups, which did not differ from each other. We conclude that the aerosolization method is suitable for differentiating increased from normal permeability.

Aerosols↗

PubMed1975

The effect of an intraduodenal elemental diet on pancreatic secretion.

The effect of an elemental diet on canine exocrine pancreatic secretion was evaluated by infusing an elemental diet into the duodenum of dogs and monitoring the output of the pancreas. The stimulatory properties of the elemental diet were compared with a nearly equimolar dose of an L-form neutral amino acid, 0.16 normal hydrochloric acid, and 2 units per kilogram per hour of exogenous cholecystokinin. Intraduodenal infusion of elemental diet produced significant increases in pancreatic volume and protein output. These changes were similar to those produced by the amino acid solution and suggest that the stimulatory properties of the elemental diet are primarily due to the amino acid content. The results of the this study suggest that elemental diets stimulate the duodental mucosa to secrete cholecystokinin which stimulates the exocrine pancreas. Elemental diets administered in such a manner that the substance passes through the duodenum would not theoretically be a satisfactory method of providing calories to patients with acute pancreatitis.

Animals↗

PubMed1975

A new fluorescent method for the demonstration of macromolecular aldehydes.

The fluorochrome, p-hydrazinoacridine (HA), is used to stain selectively natural macromolecular aldehydes as occur in elastic tissue as well as periodic acid (oxidized) or hydrochloric acid (hydrolyzed) engendered polyaldehydes (e.g., respectively of glycogen, mucosubstances and deoxyribonucleic acid). The reaction is independent of SO2 required in Schiff-type reactions. The mechanism of the staining reaction is presumably via the formation of fluorescent hydrazones from aldehyde condensation with HA. Aldehyde blocking agents, i.e., thiosemicarbazide and sodium borohydride, block the staining reactions with HA. In view of the controversy surrounding the mechanism of Schiff-type reactions and the lack of an adequate explanation for the affinity of miscellaneous fluorochromes for elastic tissue, p-hydrazinoacridine appears to be an ideal reagent, combining a simple staining procedure, excellent histological results and a straightforward mechanism for its selectivity.

Acridines↗

PubMed1978

[Pulse cytophotometrical investigations about the resistance of DNA against acid hydrolysis influenced by ageing and cortisol (author's transl)].

The resistance of nuclear chromatin against acid hydrolysis with hydrochloric acid was studied in cell nuclei of different organs from young and old rats and after application of cortisol. Suspensions of cell nuclei from liver, spleen, kidney, heart muscle and mucosa from small intestine were stained with ethidium bromide without and after hydrolysis. The relative fluorescence intensity (FI) of every pair was measured by flow through cytophotometry. Always the FI of the diploid peaks of the hydrolysed samples was diminished. The resistance against hydrolysis was greater in old animals than in young. After application of cortisol in vivo in all organs, except in the liver, the resistance against hydrolysis was increased. Only the nuclei of liver from old animals showed a diminution of resistance after cortisol. It is assumed, that the greater resistance in age is due to the diminished functional ability of the nuclear chromatin. In the most organs, the inhibitory activity of cortisol to the cell metabolism is known, only in the liver cell it stimulates the synthesis of RNA and protein. This is in agreement with our findings.

Aging↗

PubMed1979

Destruction of Toxoplasma gondii by HC1 solution.

It was shown that the destruction of Toxoplasma gondii by pepsin-HCl solution was due to the acid only. Endozoites were destroyed faster by hydrochloric acid than cystozoites. Furthermore, endozoites were stained faster than cystozoites in an alkaline solution of methylene blue. For this reason, endozoites were assumed to have a higher permeability than cystozoites. The action of hydrochloric acid was used for demonstration of cystozoites in mouse peritoneum cavity. No cystozoites were found after inoculation of virulent parasites.

Hydrochloric Acid↗

PubMed1989

The effect of anticoagulants, enzyme inhibitors and long term storage on the extraction of known concentrations of methionine enkephalin in human plasma.

The stability of methionine enkephalin (M-E) during long term storage was investigated using various anticoagulants and enzyme inhibitors, eg EDTA, heparin, trasylol, citric acid. Plasma was stored for different lengths of time up to six weeks. High pressure liquid chromatography (HPLC) was used to separate and quantify M-E. We found that EDTA, heparin or trasylol per se are ineffective in preserving M-E for short term extraction. Blood collected in chilled heparin tubes with citric acid crystals and the plasma further acidified with hydrochloric acid gave the highest recovery. With storage times up to six weeks further degradation was marked in samples taken in plain tubes but did not occur with tubes containing citric acid crystals and hydrochloric acid.

Anticoagulants↗

PubMed2005

New, simple and validated UV-spectrophotometric methods for the estimation of gatifloxacin in bulk and formulations.

New, simple and cost effective UV-spectrophotometric methods were developed for the estimation of gatifloxacin in bulk and pharmaceutical formulations. Gatifloxacin was estimated at 286 nm in 100 mM phosphate buffer (pH 7.4) and 292 nm in 100 mM hydrochloric acid (pH 1.2). Linearity range was found to be 1-18 mug ml(-1) (regression equation: absorbance=0.0684 x Concentration in microg ml(-1) + 0.0050; r2 = 0.9998) in the phosphate buffer (pH 7.4) and 1-14 microg ml(-1) (regression equation: absorbance = 0.0864 x Concentration in microg ml(-1) + 0.0027; r2 = 0.9999) in hydrochloric acid medium (pH 1.2). The apparent molar absorptivity was found to be 2.62 x 10(4) l mol(-1) cm(-1) in the phosphate buffer and 3.25 x 10(4) l mol(-1) cm(-1) in hydrochloric acid media. In both the proposed methods sandell's sensitivity was found to be about 0.01 microg cm(-2)/0.001A. These methods were tested and validated for various parameters according to ICH guidelines and USP. The quantitation limits were found to be 0.312 and 0.3 microg ml(-1) in the phosphate buffer and hydrochloric acid medium, respectively. The proposed methods were successfully applied for the determination of gatifloxacin in pharmaceutical formulations (tablets, injection and ophthalmic solution). The results demonstrated that the procedure is accurate, precise and reproducible (relative standard deviation <2%), while being simple, cheap and less time consuming and can be suitably applied for the estimation of gatifloxacin in different dosage forms and dissolution studies.

Anti-Bacterial Agents↗

PubMed2000

Hydrochloric attack of serpentinites: Mg2+ leaching from serpentinites.

This paper presents the hydrochloric attack of serpentinites. Romanian serpentinites are part of the Danubian crystalline complex. These serpentinites contain mineral serpentine (magnesium silicate) and a small amount of other minerals along with calcium, iron, aluminium, nickel, cobalt, chrome and manganese. For processing, the serpentinite was attacked by hydrochloric acid from two provinces (p.a. and residual hydrochloric acid), using different experimental conditions: acid concentrations between 15-23 per cent HCl, the temperature range of 70-90 degrees C, with stoichiometric ratio between reactants and with acid excess, the extraction time being up to 180 min. In optimum conditions, the magnesium extraction is almost total (99.5 per cent). A well-balanced processing of these serpentinites looks for both the silica residue utilization and the chloride solutions, in order to separate the prevalent magnesium as well as the valuable microcomponents--nickel and cobalt.

Asbestos, Serpentine↗

PubMed1997

Selective precipitation separation and inductively coupled plasma mass spectrometric determination of trace metal impurities in high purity silver.

A simple and rapid method for the determination of some trace element impurities in high purity silver, combining the isolation of analytes from the silver matrix with selective precipitation followed by ICP-MS determination was developed. On the basis of an extreme difference in the solubilities of the chlorides of silver and the other accompanying trace elements, silver can be separated completely through the addition of hydrochloric acid. The sample of silver was at first dissolved in 7 M nitric acid followed by addition of hydrochloric acid to remove the silver matrix by formation of a silver chloride precipitate, while leaving the trace element impurities in the solution, which was subsequently analysed by ICP-MS. Eleven elements (Al, Au, Cd, Co, Cu, Fe, Mg, Mn, Ni, Pb and Sn) were determined with good accuracy and precision. The limits of detection (based on the 3 sigma criterion) of these elements were 10(-1)-10(-3) ng g-1. The proposed method was successfully applied to the determination of metal impurities in high-purity silver samples (EM9465 and EM 9343) and validated by the analysis of NIST SRM 8171 (Fine Silver FS 14).

Chemical Precipitation↗

PubMed2004

[Study on the method for determination of sulfate in Fe-catalyst by inductively coupled plasma atomic emission spectrometry].

A direct method was reported for the determination of sulfate in iron-catalyst by inductively coupled plasma atomic emission spectrometry (ICP-AES). The samples were dissolved with hydrochloric acid. The interference factors of hydrochloric acid and iron were studied. The results showed that the effect of iron on the test of sulfate was not only to cause background interference but also to depress the intensity of sulfur seriously as well, and the effect increased with the increment of iron amount. Due to the physical in terference, a high concentration of HCl also depresesed the intensity of sulfur. Matrix effect from iron and HCl were corrected by matrix matching method. The recommended method is simple and rapid, and show satisfying precision and accuracy. The recoveries were more than 97%, and the relative standard deviations of six samples were less than 3%.

Catalysis↗

PubMed1982

Antacid aspiration in rabbits: a comparison of Mylanta and Bicitra.

The effects of aspiration of (a) 2 ml of Mylanta (a particulate antacid) mixed with 2 ml of hydrochloric acid (pH 1.5), (b) 2 ml of half-strength Bicitra (a soluble antacid) mixed with 2 ml of hydrochloric acid (pH 1.5), (c) 4 ml of hydrochloric acid (pH 1.5), and (d) 4 ml of normal saline (pH 6.5) on arterial blood gas tensions and lung pathology were compared in anesthetized rabbits. PaO2 decreased similarly in all animals 15 minutes after aspiration, but recovered to normal levels 4 hours after aspiration of saline and 48 hours after aspiration of Bicitra. PaO2 remained depressed after aspiration of Mylanta and HCl. Gross and microscopic evidence of lung injury was most severe in animals that aspirated Mylanta. One animal died 8 hours after aspiration of Mylanta.

Aluminum Hydroxide↗