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PubMed1993

Secretory leukocyte protease inhibitor in cystic fibrosis.

Cystic fibrosis (CF) is a genetic disorder that leads to a defect in chloride ion transport and results in pancreatic and pulmonary insufficiency. The pulmonary disease is characterized by bacterial colonization and inflammation with excessive levels of neutrophils and neutrophil elastase within the lung. Neutrophil elastase is considered to be one of the major mediators of the pulmonary damage. Secretory leukocyte protease inhibitor (SLPI) is a natural anti-protease found in the upper airways and has been successfully produced by recombinant technology. SLPI is effective in reducing elastase-induced damage in vitro and in vivo and has recently been administered safely as an aeroeol to CF patients with evidence of biochemical efficacy.

Cystic Fibrosis↗
PubMed2005

Long-range electrostatic interactions in hybrid quantum and molecular mechanical dynamics using a lattice summation approach.

A method based on a lattice summation technique for treating long-range electrostatic interactions in hybrid quantum mechanics/molecular mechanics simulations is presented in this article. The quantum subsystem is studied at the semiempirical level, whereas the solvent is described by a two-body potential of molecular mechanics. Molecular dynamics simulations of a (quantum) chloride ion in (classical) water have been performed to test this technique. It is observed that the application of the lattice summations to solvent-solvent interactions as well as on solute-solvent ones has a significant effect on solvation energy and diffusion coefficient. Moreover, two schemes for the computation of the long-range contribution to the electrostatic interaction energy are investigated. The first one replaces the exact charge distribution of the quantum solute by a Mulliken charge distribution. The long-range electrostatic interactions are then calculated for this charge distribution that interacts with the solvent molecule charges. The second one is more accurate and involves a modified Fock operator containing long-range electron-charge interactions. It is shown here that both schemes lead to similar results, the method using Mulliken charges for the evaluation of long-range interactions being, however, much more computationally efficient.

Journal Article↗
PubMed1989

Comparison of the properties of [3H]-D-2-amino-5-phosphonopentanoic acid and [3H]-DL-2-amino-7-phosphonoheptanoic acid binding to homogenates of rat cerebral cortex.

1. The pharmacology and ionic regulation of [3H]-2-D-2-amino-5-phosphonopentanoic acid ([3H]-D-AP5) and [3H]-DL-2-amino-7-phosphonoheptanoic acid ([3H]-DL-AP7) binding to homogenates of rat cerebral cortex were examined using radioligand binding methodology. 2. Both [3H]-D-AP5 and [3H]-DL-AP7 labelled a single population of binding sites with dissociation constants of 0.39 and 1.8 mumol/l, respectively. The density of binding sites found with [3H]-DL-AP7 was 13 times greater than that found with [3H]-D-AP5. 3. The ionic requirements of the [3H]-D-AP5 binding site in the presence of chloride were such that calcium acetate enhanced binding, while magnesium and sodium acetate both decreased binding. In the absence of chloride both calcium and chloride ions stimulated binding. 4. In a chloride-free buffer calcium acetate stimulated binding of [3H]-DL-AP7 in a biphasic manner. Chloride ions (ammonium salt) enhanced binding slightly at low concentrations (0.1-1.0 mmol/l) above which binding was reduced to non-specific levels. The ionic dependence of [3H]-DL-AP7 binding had some similarities to the previously defined GLU-C site. 5. The pharmacological profile of the site labelled by [3H]-D-AP5 was consistent with that of a recognition site for N-methyl-D-aspartate (NMDA) as defined in electrophysiological experiments. [3H]-DL-AP7 did not label an NMDA site as several non-NMDA ligands displaced binding with high affinity and the binding was not stereospecific as found for [3H]-D-AP5. Moreover, the pharmacological profile of the [3H]-DL-AP7 site did not correspond to any excitatory amino acid receptor as presently defined.

2-Amino-5-phosphonovalerate↗
PubMed1977

Inhibition of antigen- and mitogen-induced human lymphocyte proliferation by gold compounds.

Gold sodium thiomalate (GST) inhibited in vitro antigen- and mitogen-triggered human lymphocyte DNA synthesis. Inhibition of responsiveness was observed with concentrations of GST equivalent to gold levels found in serum or tissues of patients receiving chrysotherapy, Inhibition was dependent upon the gold ion itself since GST and gold chloride were both inhibitory whereas thiomalic acid was not. Inhibition could not be explained by nonspecific killing of cells or by an alteration in the kinetics of the responses. GST inhibited mitogen-induced proliferation most effectively when present from the initiation of culture and could not inhibit the responsiveness of cells which previously had been activated by concanvalin A. These findings indicated that GST blocked a critical early step in lymphocyte activation. The degree of GST-induced inhibition of proliferation was increased in cultures of cells partially depleted of monocytes. Moreover, inhibition was reversed by supplementation of these cultures with purified monocytes. These observations suggested that GST blocked thymus-derived (T)-lymphocyte activation by interfering with a requisite function of the monocyte population in initiating such responses. Prolonged incubation of peripheral blood mononuclear cells with GST resulted in diminished mitogen responsiveness upon subsequent culture in the absence of gold. The addition of fresh monocytes restored responsiveness to these populations. Furthermore, preincubation of purified monocytes with GST rendered them deficient in their ability to support mitogen-induced T-lymphocyte proliferation on subsequent culture. These observations indicate that the major effect of GST results from interference with the functional capability of the monocyte population.

Antigens↗
PubMed1981

Effect of methacholine on Na+ pump activity and ion content of dispersed avian salt gland cells.

The effects of the cholinergic agonist methacholine chloride (MCh) on cellular ion content and Na+ pump activity of dissociated duck salt gland cells were studied. Dispersed salt gland cells regulate intracellular ion levels in a ouabain-sensitive manner. MCh (0.5 mM) caused no detectable change in cell Na+ levels over the first 10 min of exposure of cells to the agonist but elicited decreases of 23 and 13%, respectively, in intracellular Cl- and K+ content. The rate of turnover of salt gland cell plasmalemmal Na+ pumps, as measured by [3H]ouabain binding to the dissociated cells, was markedly stimulated by 0.5 mM MCh, although the total number of binding sites at equilibrium remained unchanged. Replacement of medium Na+ with choline abolished the MCh-stimulated increase in ouabain binding but had no effect on the rate of glycoside binding in the absence of the agonist. Substitution of Cl- in the medium by NO3-, SO42-, or benzene sulfonate- reduced the stimulated component of Na+ pump turnover by 85-90%. Addition of 1 mM furosemide to the medium abolished the increase in ouabain binding and ouabain-sensitive oxygen consumption observed after exposure of salt gland cells to MCh. These data are consistent with the hypothesis that cholinergic stimulation of salt gland cells triggers a Cl--dependent uptake of Na+, which elicits a compensatory increase in Na+ pump turnover. In addition, the decrease in cellular Cl- content caused by MCh suggests that the agonist either directly or indirectly mediates an efflux of Cl- from the cells.

Animals↗
PubMed1995

Analysis of sweat chloride by reversed phase high-performance liquid chromatography.

A high-performance liquid chromatography (HPLC) method for the determination of sweat chloride was developed and evaluated. This method is capable of measuring chloride ion in sweat eluates with an analytical working range from 0.5 mmol/L to 6 mmol/L (15 to 180 mmol/L in undiluted sweat samples). Precision studies showed that at the levels of 1 mmol/L, 2.5 mmol/L and 3.5 mmol/L, the within batch coefficients of variation were 1.26%, 0.88% and 0.43%, respectively, and the between batch coefficients of variation were 1.31%, 1.75% and 1.07%, respectively. The minimum detection limit was 0.5 mmol/L. This method correlated well with the ion-selective electrode (ISE) method currently in use.

Chlorides↗
PubMed2006

Ion chromatographic determination of trace iodate, chlorite, chlorate, bromide, bromate and nitrite in drinking water using suppressed conductivity detection and visible detection.

An ion chromatography method for the simultaneous determination of trace iodate, chlorite, chlorate, bromide, bromate and nitrite in drinking water has been developed using an anion-exchange column and the suppressed conductivity detector, followed by post-column addition of reagent to enhance visible absorbance detection of ions. A high capacity anion exchange Ion Pac9-HC column (250 mm x 4 mm I.D.) was used. Eight millimole per liter sodium carbonate was used as eluent, an auto-suppression external water mode was selected, 0.5 g/l o-dianisidine.2HCl (ODA)+4.5 g/l KBr+25% methanel+5.6% nitric acid was used as post-column reagent. The post-column reaction (PCR) temperature was at 60 degrees C, and the visible absorbance detected wavelength at 450 nm. The sample's pH and coexist anions had no influence on determination. The method enjoyed a wide linear range and a good linear correlation coefficient (r>0.999). The method detection limits were between 0.023 and 2.0 microg/l. The average recoveries ranged from 87.5 to 110.0%, and the relative standard deviations (RSD) were in the range of 1.1-4.6%. The analytical results by the method of post-column addition of reagent to enhance visible absorbance detection of anions was compared with that of the suppressed conductivity detection, and the former was proved to be better in sensitivity and selectivity. The results showed that this method was accurate, sensitive and might be good for application and suitable for trace analysis at the level of mug/l.

Anions↗
PubMed1989

Synergistic induction of rat hepatic ornithine decarboxylase by multiple doses of cobalt chloride.

The level of rat hepatic ornithine decarboxylase (ODC) induced by repetitive administration of Co2+ was determined by affinity labeling with [3H]difluoromethylornithine. Such a treatment with Co2+ ion induced ODC level to a 10-fold greater extent than single dose of the metal ion or well-known inducers of the enzyme, such as thioacetamide or carbon tetrachloride. The half life of ODC activity induced by repetitive treatment with Co2+ (95 min) was substantially increased to about 10-fold over the value obtained from the enzyme induced by single treatment with the metal ion (10 min). ODC activity induced by repetitive treatment with Co2+ was separated into two peaks by DEAE-Sepharose column chromatography. The two independently collected fractions of ODC peaks exhibited different affinity for pyridoxal 5'-phosphate in vitro and sensitivity to cycloheximide in vivo.

Animals↗
PubMed2000

Electrospray ionization tandem mass spectrometric studies of competitive pyridine loss from platinum(II) ethylenediamine complexes by the kinetic method.

The competition between pyridine ligand loss in square planar Pt(II) complexes has been examined using the doubly and singly charged ions of complexes consisting of platinum(ethylenediamine) coordinated to two different substituted pyridines. Collision induced dissociation (CID) of [Pt(en)Py(1)Py(2)](2+) (where Py(1) = one of ten different substituted pyridines and Py(2) = pyridine) results in loss of the protonated pyridines to yield the singly charged platinum ions [Pt(en)Py(1)-H](+) and [Pt(en)Py(2)-H](+). In contrast, fragmentation of [Pt(en)Py(1)Py(2)-H](+) results in neutral pyridine loss to yield the ions [Pt(en)Py(1)-H](+) and [Pt(en)Py(2)-H](+). In the latter case, the correlation between relative losses of each pyridine compared to their gas-phase proton affinities is poor. A novel chloride ion abstraction reaction occurs for the fragmentation of [Pt(en)Py(1)Py(2)](2+) when Py(1) = o-C(5)H(4)CIN and Py(2) = C(5)H(5)N, to yield the [Pt(en)(Cl)Py(2)](+) and [o-C(5)H(4)N](+) pair of ions. In order to model this process the competition between nitrogen and chlorine binding in [Pt(NH(3))(3)(o-NC(5)H(4)Cl)](2+) has been examined using density functional theory (DFT) calculations at the B3LYP/LANL2DZ level of theory. Both adducts are minima with the N adduct being more stable than the Cl adduct by 22.7 kcal mol(-1). Furthermore, the Cl adduct exhibits a significant stretching of the C-Cl bond (to 1.935 A), consistent with the observed chloride ion abstraction reaction, which is endothermic by 9.0 kcal mol(-1) (relative to the N adduct).

Chlorides↗
PubMed1986

Determination of the bioavailability of the quaternary compound trospium chloride in man from urinary excretion data.

For the quaternary compound trospium chloride (Spasmex) which is used as an anticholinergic agent a new sensitive assay method has been developed that allows the quantitative determination of the drug in human urine and plasma. Using this method it was possible to obtain pharmacokinetic data from plasma levels and urinary excretion, and to determine the bioavailability in man. Quantitative determination is performed by alkaline hydrolysis to the corresponding spiroalcohol, ion-pair extraction with dipicrylamine, subsequent derivatization with the fluorophor benoxaprofen chloride, and ion-pair chromatographic separation on a reversed-phase column with chloride as the counter-ion using a mixture of acetonitrile and water. In healthy volunteers (n = 6) the plasma concentration time curve after intravenous administration of 0.5 mg trospium chloride could be described by an open two-compartment model. The mean half-lives were 2.7 and 97 min, respectively. After oral administration of 10 mg the highest concentration found in plasma was 1.4 ng trospium chloride/ml. 55% of the given dose were excreted unchanged into urine within 48 h after i.v. administration, the corresponding value after oral administration was 1.6%. If no hydrolysis is carried out in urine samples the spiroalcohol can be detected as metabolite of trospium. Within 48 h after i.v. administration 4% and after oral administration 0.3% of the given dose are excreted into urine as spiroalcohol. From the cumulative excretion of trospium into urine within 48 h a mean bioavailability of 2.9% was calculated.

Administration, Oral↗
PubMed2001

Ion chromatographic determination of lithium at trace level concentrations. Application to a tracer experiment in a high-mountain lake.

The water residence time of a high-mountain seepage lake in the Austrian Alps was derived from the flushing rate of a tracer substance. A diluted lithium chloride solution was injected into the lake during holomictic conditions in order to favour the homogeneous distribution of the tracer. The exponential decline of the mass of lithium in the lake revealed a water residence time of 1.5 to 3 months for summer and almost no lake water exchange during winter. Lithium concentrations ranged from background values of 0.06 microg l(-1) to about 3 microg l(-1) immediately after the tracer injection. Lake water samples were analyzed with ion-exchange chromatography using a Dionex device with a CS 12A separation column. The method detection limit determined according to the definition of the US Envirinmental Protection Agency amounted to 0.009 microg l(-1).

Chromatography, Liquid↗
PubMed1984

Sodium N-methyl-D-glucamine dithiocarbamate and cadmium intoxication.

The sodium and ammonium salts of N-methyl-D-glucamine dithiocarbamate were prepared and their usefulness as antidotes for cadmium intoxication investigated. This chelating agent was found to be effective in both acute and repeated exposure cadmium poisoning. A single intraperitoneal injection of sodium N-methyl-D-glucamine dithiocarbamate (NaNMG-DTC), administered at a level greater than 1.1 mmol/kg body weight, protects against a normally lethal (greater than 95%) dose of cadmium chloride (10 mg CdCl2/kg body weight) and results in a subsequent dose-dependent decrease in the liver and kidney burdens of cadmium ion. In repeated exposure cadmium intoxication, repeated administration of NaNMG-DTC can result in substantial reductions in both the kidney (71%) and the liver (40%) levels of cadmium. The LD50 of the compound was not determined, but single injections of 26.6 mmol/kg body weight (injectate volume 1.0 ml) are well tolerated in mice.

Animals↗
PubMedDate not supplied

Determination of thallium in potassium chloride and electrolyte replenishers by electrothermal atomic absorption spectrometry.

Thallium in potassium chloride and electrolyte replenishers was determined by electrothermal atomic absorption spectrometry (ETAAS) with direct injection of a resin suspension. Thallium(III) was extracted on fine particles of a cellulose nitrate resin (CNR) from dilute HCl (pH 1.6) in the presence of ammonium pyrrolidine-1-carbodithioate. The CNR particles were collected on a membrane filter by filtration under suction, suspended in 1.0 mL 10mM HNO3, and then delivered directly to ETAAS as the suspension. The effects of chloride ions were thoroughly investigated. The results showed that the addition of 0.5mM NaCl to the suspension (10mM HNO3) was recommended, after CNR and a membrane filter holding the CNR were washed thoroughly with 0.025M HCl, to eliminate interference from chloride ions. No chemical modifier was required. Extraction from the solution containing up to 2M chloride ion was allowable. The proposed method gave a concentration factor of 50 for a 50 mL sample volume. The detection limit (3sigma, n = 5) was 1 ng (20 pg/mL). The relative standard deviation was 4.9% (n = 5) at 30 ng level of thallium. The content of thallium in potassium chloride was 15.7-32.8 ng/g, and in electrolyte replenishers was 0.18-4.16 ng/mL.

Calibration↗
PubMed1994

Activity of triphenylselenonium chloride in mammary cancer prevention.

The present study was designed to evaluate the tolerance and cancer chemopreventive activity of triphenylselenonium chloride in female Sprague-Dawley rats. No information is available in the literature on the anticarcinogenic efficacy of a lipophilic cationic selenium compound as exemplified by the triphenylselenonium ion. A short-term preliminary study indicated that it was well tolerated via the dietary route. Supplementation at levels up to 200 p.p.m. Se did not produce any apparent adverse effect in the animals. In the dimethylbenzanthracene mammary cancer model, a level of 30 p.p.m. Se in the diet reduced the total tumor yield by approximately 70% when treatment was applied during either the initiation phase or the post-initiation phase. In the MNU mammary cancer model, the inhibitory response was expressed only during the post-initiation phase. These findings suggest that the triphenylselenonium ion may have multiple modes of action in suppressing the development of neoplasia. Tissue analysis confirmed that there was minimal accumulation of total selenium until the level of supplementation reached 100 p.p.m. Se or above. Our study therefore convincingly demonstrates that triphenylselenonium chloride fits the criteria of an effective and desirable anticancer agent with a distinct separation between the chemopreventive dose range and the toxic dose range.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1995

Expression of cystic fibrosis transmembrane conductance regulator in human gallbladder epithelial cells.

BACKGROUND: Hepatobiliary complications in cystic fibrosis result predominantly from lesions of the biliary epithelium. These abnormalities affect the intrahepatic as well as extrahepatic bile ducts and the gallbladder. The protein cystic fibrosis transmembrane conductance regulator (CFTR), the gene product defective in cystic fibrosis, functions as a cAMP-activated chloride channel in the plasma membrane. As such, it may represent an important driving force for fluid transport across the epithelium. EXPERIMENTAL DESIGN: The purpose of this study was to investigate the expression of CFTR in human gallbladder epithelial cells and to examine the chloride ion transport properties of these cells. Immunolocalization was performed on tissue sections. The reverse transcription-PCR was used to analyze the expression of CFTR mRNA in freshly isolated and cultured gallbladder epithelial cells. The CFTR protein was detected by Western blotting and immunoprecipitation. The chloride ion transport properties of the cells were determined by 36Cl efflux studies. RESULTS: The CFTR protein was immunodetected in human gallbladder in situ and localized predominantly to the apical membrane of epithelial cells. High levels of CFTR mRNA and protein were maintained in gallbladder epithelial cells in primary cultured. Glycosylated forms of CFTR were present as confirmed by treatment with N-glycanase. Chloride efflux was stimulated by Ca(++)-dependent pathways but more intensely by cAMP-dependent pathways. Stimulation of chloride efflux by agonist of the cAMP-pathway was inhibited by diphenylamine carboxylic acid, a chloride channel blocker. Two physiologically active peptides--acting via cAMP, vasoactive intestinal peptide, and secretin--also stimulated chloride efflux in vitro. CONCLUSIONS: Our results are consistent with a high expression of endogenous functional CFTR protein in human gallbladder epithelial cells. Physiologically active peptides, vasoactive intestinal peptide and secretin, stimulate chloride conductance in these cells. These findings indicate that CFTR play an important role in the pathophysiology of the biliary epithelium, including the gallbladder epithelium.

Base Sequence↗
PubMed2004

Gas chromatography-mass spectrometry analysis of alkylphenols in produced water from offshore oil installations as pentafluorobenzoate derivatives.

A simple, highly selective and sensitive method for the determination of 14 representative alkylphenols from phenol (C0) to nonylphenol (C9) in produced water is described. Solid-phase extraction (SPE) by anion-exchange sorbent is used to extract alkylphenols from produced water. The samples are then derivatised by pentafluorobenzoyl chloride and analysed on GC-MS (negative ion chemical ionisation, NCI). The derivatisation procedure has been validated by means of two-level factorial design (2(7-4)) experiments. Quantification is done with isotope dilution of five internal standards of different alkyl chain length. The detection limits were at low ng/l levels. A comparison with GC-MS analysis of non-derivatised alkylphenol samples revealed the advantage of derivatisation as described in the method.

Gas Chromatography-Mass Spectrometry↗
PubMed1990

[The participation of sodium and chlorine ions in the reactions of the secretory cells and alveolar myoepithelium of the mammary gland].

The MP levels of the mammary gland's secretory cells and transepithelial differences of potential were found to depend on extracellular ions of sodium and chloride in lactating white mice. Substitution of the sodium ions with the choline ions increased a little the difference of potentials, whereas substitution of the chloride ions with sulfuric acid ions decreased it. Transepithelial electrical resistance increased in both cases. Substitution of the sodium ions with ions of choline and of the chloride ions with sulfuric acid ions suppressed hyperpolarization changes of the MP and increased the transepithelial difference of potentials. Contractile responses of myoepithelial cells to the action of acetylcholine and oxytocin were also depressed. The sodium and chloride ions seem to affect simultaneously the processes of the potassium ions release from secretory cells and contractile responses of the alveoli's myoepithelial cells.

Acetylcholine↗