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Results for “Chloride Ion Level”

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At least 73 records · Page 4Linked to original sources

PubMed1993

Vinyl carbamate epoxide, a major strong electrophilic, mutagenic and carcinogenic metabolite of vinyl carbamate and ethyl carbamate (urethane).

Vinyl carbamate epoxide (VCO) was found to possess strong electrophilic, mutagenic and carcinogenic activities. It reacted with water at 37 degrees C and pH 7.4 (phosphate buffer) to form glycolaldehyde and several related reducing compounds; none of these products were mutagenic for Salmonella typhimurium TA1535. Under these conditions VCO had a half-life (determined chemically and mutagenically) of approximately 10.5 min. This half-life was progressively lowered by increasing concentrations of chloride ion (liver, serum and isotonic levels). This ion reacted with VCO to form chloroacetaldehyde. VCO also reacted with other nucleophiles such as glutathione, DNA and its constituent guanine and adenine bases. The purine adducts formed by VCO in DNA in vitro and in vivo were released by weak acid treatment and consisted of 7-(2'-oxoethyl)guanine and N2,3-ethenoguanine as major products with 1,N6-ethenoadenine as a minor product. VCO was a strong direct mutagen in Salmonella typhimurium TA1535 and TA100 but was only weakly active in the TA98 mutant. VCO was a stronger initiator of carcinogenesis in the skin of CD-1 mice and in the liver of infant male B6C3F1 mice than its metabolic precursors vinyl carbamate (VC) and ethyl carbamate (EC). Unlike VC and EC, VCO was a strong complete carcinogen in the skin of CD-1 mice and induced papillomas and carcinomas following repetitive administration of sub-ulcerogenic doses. VCO also exhibited some carcinogenic activity in the lungs of mice and in the s.c. and mammary tissue of female Sprague-Dawley rats. These data and those from other recent studies support the conclusion that VCO is a major strong electrophilic, mutagenic and carcinogenic metabolite of EC and VC in the mouse.

Animals↗

PubMed1994

[Neurochemical approach to epilepsy].

To elucidate the neurochemical mechanism of epilepsy, we investigated the role of neurotransmitter systems in the animal models of epilepsy, the mechanism of anticonvulsants and proconvulsants, the neurotransmitters in the CSF of children with epilepsy, and the new therapy for epilepsy. The main results are as follows. 1) In El mice, the increased activity of excitatory amino acids system in cortex and decreased activity of noradrenergic system in striatum and hippocampus were related to the increased seizure susceptibility. 2) GABA sensitivity was reduced in young DBA 2 J mice which are susceptible to audiogenic seizures. 3) Lower benzodiazepine receptor densities were found in hippocampus of 4 and 16 weeks-old tremor rats. GABA concentrations in the cerebral cortex and hippocampus of the tremor rats increased at 5 weeks-old and decreased at 15 weeks-old. These changes may be related to the absence-like seizures in tremor rats. 4) Anticonvulsant mechanism of ACTH may be due to antagonizing glutamate binding. Proconvulsant mechanism of thyroid hormone may be related to the decrease in number of cerebral cortical neuronal benzodiazepine receptors. Penicillin acts its proconvulsant effect through inhibiting GABA-gated chloride ion influx. 5) CSF GABA level in children with infantile spasms was lower than in controls. The combination of vitamin B6 and valproic acid is effective and safe therapy in the treatment of infantile spasms. Further investigations by the neurochemical approaches are necessary to understand the mechanisms of epilepsy and develop the new therapy.

Animals↗

PubMed2002

Respiratory and acid-base physiology of the purple sea urchin, Strongylocentrotus purpuratus, during air exposure: presence and function of a facultative lung.

Upon exposure to air (emersion), the purple sea urchin Strongylocentrotus purpuratus releases an "emersion fluid" from its esophagus. Release of this fluid causes air to appear within the test (or calcareous theca), most likely inside the intestine. The air space is large, occupying 33.5% of the volume of the intrathecal space. The intestine containing air forms a facultative lung and contributes to the oxygenation of the perivisceral coelomic fluid (PCF) during emersion. During emersion, the mean partial pressure of oxygen (PO(2)) of the PCF declined from 56 to 24 torr (1 torr = 0.1333 kPa) after 2 h, remained relatively unchanged after 4 h, and rose to 39 torr after 8 h. The partial pressure of carbon dioxide (PCO(2)) rose from 2.6 to 3.8 torr after 2 h, remained unchanged after 4 h, and declined to 2.7 after 8 h. Due to the elevation of PCO(2) PCF pH declined from 7.41 to 7.17. PCF osmotic concentration, calcium ion concentration, chloride ion concentration, ammonium ion concentration, and protein concentration were unchanged by air exposure. Lactate levels in the PCF were undetectable. S. purpuratus was an osmoconformer and a chloride ion conformer at salinities down to 20.9 ppt. Below this salinity, the sea urchins died. The respiratory acidosis resulting from air exposure was uncompensated, supporting the hypothesis that compensation for a respiratory acidosis induced by air exposure does not occur in organisms that are unable to regulate ions in a dilute environment. We suggest that the facultative lung ensures a minimal PO(2) in the PCF, which may be especially important when the intrathecal space is full of ripe gonads, allowing the gonads to be more reliant on aerobic metabolism.

Acid-Base Equilibrium↗

PubMed1990

[Determination of thiocyanate in serum with ion-selective liquid membrane electrodes].

The manufacture of a liquid membrane type thiocyanate ion selective electrode on the basis of crystalviolet thiocyanate or methylene blue thiocyanate solved in nitrobenzene is described. This electrodes are available for the determination of the thiocyanate ion in agents with high levels on chlorid or protein, for instance in serum. Thiocyanate levels in serum from smokers and nonsmokers determinated by this electrodes differ significant from values that were obtained by the barbituric acid method, but they were in good agreement with values determinated by ion exchange chromatography. It can be assumed that its possible to ascertain the part of the dissociated thiocyanate by means of the ion selective electrodes and the ion exchange chromatography.

Chemical Phenomena↗

PubMed2002

Automated trace anion determinations in concentrated electronic grade phosphoric acid by ion chromatography.

Modifications have been made to the method of ion-exclusion pre-separation followed by ion exchange with conductivity detection for the determination of trace levels of chloride, sulfate and nitrate in concentrated phosphoric acid. Ion-exclusion separation and pre-concentration of impurity anions is performed using Dionex AS6-ICE and AS11-HC (4 mm) columns, respectively, with water eluent. Final separation is performed using Dionex AG11-HC and AS11-HC (2 mm) columns, KOH gradient elution, and suppressed conductivity detection. Improvements to the method include addition of an autosampler and eluent generator, and use of external standard calibration. These instrumental and procedural changes significantly improve the method's throughput, while the method's capability relative to phosphoric acid specifications is maintained, as verified through statistical evaluation of control sample analyses. Detection limits of 60, 680, and 4,0 ppb (w/w) are obtained vs. semiconductor-grade phosphoric acid specifications of 1000, 12,000, and 5000 ppb for chloride, sulfate, and nitrate, respectively.

Anions↗

PubMed2001

Potassium ion release from a glass ionomer cement matrix.

Glass ionomer was mixed with water alone and with water containing two levels of potassium ion, added as potassium chloride. The dimensions of the specimens varied; discs, cylinders and a rectangular bar were used. Release of potassium was measured until it ceased. A little potassium was released from cement mixed with water but could be accounted for by traces present in the glass. Release took 2 months for the lower level and 1.5 years for the higher level of addition. For some specimen groups not all the potassium added was subsequently released. Potassium release tended towards the pattern found for fluoride release naturally occurring from glass ionomer cements in being proportional to t 1/2 but was less certain at the lower addition. Release was not related to the dimensions of the sample as has been shown for release of intrinsic fluoride.

Cations, Monovalent↗

PubMed2002

Decreased anion gap in polyclonal hypergammaglobulinemia.

OBJECTIVES: The anion gap has proved a valuable tool in the diagnosis of various forms of acid-base disorders, although the importance of slight rises in the anion gap remains unclear. The concept of the anion gap is often misunderstood and misapplied. The relationship between gammaglobulins and the serum anion gap has not received much attention except for reports of a narrowing of the gap associated with certain monoclonal immunoglobulin G gammopathies. We present patients with polyclonal gammopathy, the magnitude of which correlated strongly and negatively with the anion gap. DESIGN: The anion gap can be readily calculated from routine laboratory data, and anion gap was calculated as ([Na] +[K])- ([Cl] + [HCO3]). SUBJECTS: Serum anion gaps were determined in 206 patients with polyclonal hypergammaglobulinemia and 63 healthy subjects. MEASUREMENTS: Serum sodium and potassium ions concentration were determined by flame photometry. Serum bicarbonate level was measured as total carbon dioxide content. Serum chloride level was determined by chlorimetric titration with silver ions. RESULTS: All patients with polyclonal hypergammaglobulinemia had a statistically significant reduction in their mean serum anion gaps (6.4 +/- 1.2 mmol/L) when compared with normal control volunteers (15.3 +/- 2.4 mmol/L), p < 0.05. CONCLUSIONS: Our results show a negative correlation between serum anion gap and gammaglobulins concentration.

Acid-Base Equilibrium↗

PubMed1985

Application of indirect photometric chromatography to pharmaceutical analysis.

Indirect photometric chromatography, which couples analyte separation by ion exchange with indirect photometric detection, is applied to the analysis of complex solutions encountered in the pharmaceutical industry. Applications of primary interest include simultaneous acetate, lactate, chloride, or phosphate determinations, a bisulfite/sulfate assay, and quantitation of trace levels of chloride in deionized water. Three commercially available ion chromatography columns are studied for their suitability in these applications. Due primarily to (A) the acid-base chemistry of the phosphate and bisulfite ions, (B) the need to stabilize the readily oxidized bisulfite, and (C) resin stability at high pH, the column packed with a polymer-based resin is capable of producing analytically superior separations of Cl-, HPO4-2, and matrix components and of SO3-2/SO4-2 in the samples of interest. Under rigid relative concentration conditions, the columns packed with a silica backbone resin are capable of separating acetate, lactate, Cl-, and H2PO4- with baseline resolution and are effective for determining Cl- levels at concentrations of less than one part-per-million.

Acetates↗

PubMed1977

The effect of external salinity on drinking rate and rectal secretion in the larvae of the saline-water mosquito Aedes taeniorhynchus.

1. The drinking rate of the saline-water mosquito larva Aedes taeniorhyncus (100 nl.mg-1.h-1) is unaffected by the salinity of the external medium, but is directly proportional to the surface area of the animal. 2. Haemolymph Na+, Mg2+, K+, Cl-, SO42- and osmotic concentrations were measured in larvae adapted to 10%, 100% and 200% seawater and were found to be regulated within a narrow range. 3. With the exception of potassium, ionic concentrations in rectal secretion were found to increase with increasing concentrations of the sea water in which larvae were reared. 4. The osmotic concentration of rectal secretion was unaffected by changes in haemolymph osmotic concentration but did rise when sodium or chloride concentrations of the haemolymph were increased. High levels of these ions also stimulated the rate of fluid secretion. 5. Transport of chloride and sodium by the rectum exhibits the kinetics of allosteric rather than classical enzymes.

Aedes↗

PubMed1992

Cooperative gating of chloride channel subunits in endothelial cells.

New methods are described to detect subconductance levels and to analyse ion channel gating. These methods are applied to simulated and experimental data. Single chloride channel records from inside-out membrane patches excised from human umbilical venous endothelial cells (HUVEC) exhibit, in addition to the full closed and full open configurations, intermediate subconductance levels which are multiple of an elementary conductance of 112.5 pS. Analysis of transitions from one state to another and the comparison of real data with simulated data leads to the proposal of a cooperative model of gating for the observed subunits of a chloride channel.

Chloride Channels↗

PubMed2006

[Preparation and testing of buffered eye drops containing pilocarpine chloride with timolol maleate].

BACKGROUND/AIM: In glaucoma therapy beta-blocator, timolol-maleate, is the first-line medicine of selection, whereas a miotic, pilocarpine chloride, is one of the oldest medicines used for the treatment of this illness. They are applied as eye drops. In order to achieve a better therapeutic effect and improve life quality of the ill, we produced and tested eye drops formulations based on combining pilocarpinechloride and timolol maleate in buffers of diferent pH values. METHODS: Following the general pharmacopoeial eye drops preparation regulation, we prepared formulations, of solution type, of pilocarpine chloride and timolol maleate combination, of pilocarpine choloride alone and of timolol maleate alone. A modified phosphate buffer according to Sorensen at 7.4, 7.7 and 8.0 pH values was used as a solvent. The quality of the produced formulations was examined using physical and physico-chemical methods and biological tests. Following pharmacopoeial regulations, we examined clarity, pH value and sterilty. Pilocarpine chloride level was determined by means of ion-par (High Performance Liguid Chromatography) RP-HPLC method, whereas UV/VIS absorption spectrophotometry was used for determining the level of both timolol maleate, and timolol. RESULTS: Results showed that monocomponent and combined preparations complied with the regulation demands. With the increase in the pH value of the solution pilocarpine chloride level decreased in relation to its initial content, whereas timolol level showed a tendency of moderate increase. CONCLUSION: Magistrally prepared pilocarpine chloride eye drops with timolol maleate have satisfied all the required conditions for an ophtalmological preparation. A modified phosphate buffer according to Sorensen at 7.4 pH value proved to be the most optimal solvent.

Adrenergic beta-Antagonists↗

PubMed1976

Light-chain nephropathy. Renal tubular dysfunction associated with light-chain proteinuria.

We observed idiopathic light-chain proteinuria in a patient with multiple abnormalities of proximal-tubule transport mechanisms (Fanconi syndrome), nephrogenic diabetes insipidus, and distal renal tubular acidosis. Seventeen of the 19 urinary amino acid levels measured were elevated. Uric acid and phosphate clearances were greater than 60 per cent and 50 per cent, respectively, of the simultaneous inulin clearance. When water deprivation was coupled with vasopressin administration, the maximum urinary concentration observed was 384 mOsm per kilogram of water. During ammonium-chloride loading, the level of hydrogen-ion concentration in the urine remained less than 100 times that in the blood. Kappa light-chain excretion was 149 mg per 24 hours. It appears that the concurrence of proximal tubular dysfunction, distal tubular dysfunction and light-chain proteinuria represents a distinct syndrome, which we call "combined light-chain nephropathy." Available evidence indicates that excessive light-chain production with subsequent filtration, reabsorption and catabolism, causes the complex tubular dysfunctions observed.

Acidosis, Renal Tubular↗

PubMedDate not supplied

Multidrug resistance-associated protein (MRP) mediated transport of daunomycin and leukotriene C4 (LTC4) in isolated plasma membrane vesicles.

Studies have been carried out to examine in vitro drug transport in plasma membrane vesicles isolated from HL60/ADR cells that overexpress MRP. The results demonstrate that glutathione (GSH) enhances transport of daunomycin. A greater increase in transport activity occurs when the reaction is carried out in the presence of both GSH and sodium chloride. Sodium chloride alone has no effect on daunomycin transport. It has also been observed that GSH in the presence of sodium chloride induces a major increase in the transport level of LTC4. Thus far, no metal ion other than sodium chloride has been found to be active in the drug transport system. Kinetic analysis reveals that GSH in the presence of sodium chloride greatly reduces Km and increases Vmax, for daunomycin. Additional studies show that ATPase activity in isolated plasma membrane from HL60/ADR cells is greatly enhanced in the presence of both GSH and sodium chloride. These results suggest the possibility that GSH and sodium chloride stimulate MRP-mediated transport as a result of increased ATPase activity.

ATP-Binding Cassette Transporters↗

PubMed1995

Activation of intestinal Na-K-2Cl cotransport by 5'-AMP requires F-actin remodeling.

BACKGROUND: Although cyclic adenosine monophosphate (cAMP)-dependent intestinal chloride ion (Cl-) secretion is regulated primarily at the level of apical Cl- channels, cAMP also elicits basolateral microfilament remodeling and activates basolateral sodium-potassium-2 chloride (Na-K-2Cl) cotransport. Without these additional events, secretion is inhibited. However, it is unclear whether microfilament-dependent activation of Na-K-2Cl cotransport is a direct effect of cAMP or a secondary response to the opening of apical Cl- channels. METHODS: Using the human intestinal epithelial cell line T84, we examined Cl- secretion elicited by 5'-adenosine monophosphate (5'-AMP), a novel agonist that activates apical Cl- channels without elevation of intracellular cAMP. RESULTS: 5'-AMP was found to activate basolateral Na-K-2Cl cotransport, but such regulation was abolished by the actin stabilizer, phalloidin. CONCLUSIONS: Basolateral Na-K-2Cl cotransport appears to be regulated, at least in part, as an indirect response to activation of apical Cl- channels, a pathway of regulation which may require cytoskeletal remodeling.

Actins↗

PubMed1976

The nature and action of cholera toxin.

Cholera diarrhoea is due to the action of a toxin that acts on all animal cells by stimulating the enzyme adenylate cyclase, which catalyses the production oc cyclic AMP from ATP. In intestinal brush border cells raised cyclic AMP levels result in increased secretion of chloride ions, leading to fluid accumulation in the gut. Escherichia coli produces a similar toxin. The receptor for cholera toxin on the cell membrane appears to be a complex containing the ganglioside GGnSLC (or GM1). Cholera toxin is a protein composed of two different kinds of subunits linked non-covalently. Each toxin molecule has one subunit A and four or more subunits B. Subunit B is inactive but binds to the ganglioside GGnSLC on the cell surface. Subunit A does not bind to cell membranes or gangioside and is slightly toxic to intact cells but strongly and instantly active in lysed cells. The binding of whole toxin through the B subunit to the cell is followed by a lag before subunit A penetrates the cell membrane (leaving subunit B on the surface) and stimulates the adenylate cyclase. The stimulation of adenylate cyclase depends on the presence of NAD and other co-factors present in the cell sap.

Adenylyl Cyclases↗

PubMed2002

Anion-aromatic bonding: a case for anion recognition by pi-acidic rings.

The basis for unprecedented noncovalent bonding between anions and the aryl centroid of electron-deficient aromatic rings has been demonstrated by an ab initio study of the interaction between 1,3,5-triazine and the fluoride, chloride, and azide ion at the MP2 level of theory. Minima are also located corresponding to C[bond]H...X(-) hydrogen bonding, reactive complexes for nucleophilic attack on the triazine ring, and pi-stacking interactions (with azide). Trifluoro-1,3,5-triazine also participates in aryl centroid complexation and forms nucleophilic reactive complexes with anions. This novel mode of bonding suggests the development of new cyclophane-type receptors for the recognition of anions.

Journal Article↗

PubMed1987

[Effect of disruption of chloride conductance on the development of denervation changes in muscle fiber membranes of the rat].

A decrease in resting MP, increase in the input resistance, appearance of anode breakdown APs, and extrajunctional acetylcholine sensitivity following denervation were revealed in the rat diaphragm muscle fibres. Addition of 1 X 10(-4) M furosemide to the culture medium reduced the degree of post-denervation muscle membrane depolarization and of extrajunctional acetylcholine sensitivity, but did not prevent the changes in passive electrical properties and in firing level of the muscle fibre membrane. Chloride ions could serve as intracellular messengers responsible for the neurotrophic control of muscle membrane resting potential and membrane sensitivity to acetylcholine. The Cl- are not essential in neurotrophic regulation of the electrogenic properties of membrane.

Acetylcholine↗

PubMed1990

Hyaluronic acid determinations: optimizing assay parameters.

Assay conditions for determining hyaluronic acid levels in cultured cells have been examined. In cultures labeled with [3H]glucosamine, hyaluronic acid is measured by digestion with a highly specific hyaluronidase from Streptomyces hyaluronlyticus. Products obtained in the presence and absence of preliminary enzyme digestion are precipitated with cetylpyridinium chloride. The precipitation step has been optimized for ion concentration, glycosaminoglycan carrier and for cetylpyridinium chloride levels. Chondroitin sulfate is an effective carrier in the precipitation of radiolabeled product, while unlabeled hyaluronic acid is not. Addition of sulfate to the mixture yields a flocculent precipitate that facilitates subsequent steps of the determination. Optimizing these steps in hyaluronic acid determination can generate two- to three-fold increases in apparent levels of deposition in cultured cells.

Animals↗