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At least 109 records · Page 6Linked to original sources

Chloride transport in isolated frog (Rana temporaria) skin: changes in short-circuit currently, potential, resistance, and chloride flux elicited by furosemide.

In a large number of isolated frog skins, with potential differences of from 20--92 mV (mean, 55.3 +/- 3.6 S.E.M.), the chloride influx was found to be slightly greater than chloride efflux under short-circuit conditions, but the difference was not statistically significant. However, if skins of low potential (less than 50 mV) were selected, chloride influx was significantly higher than chloride efflux (P less than 0.05). In this low potential group furosemide, (10(-3)M, applied to the solution bathing the mucosal surface) was found to produce a) a small increase in short-circuit current, which was generally apparent within 1 min, maximal in 5 min; and thereafter declined towards the control value; b) a marked increase in potential difference, apparent within 1 min and sustained for at least 30 min; c) a large and sustained increase in the calculated d.c. resistance of the skin and d) a decrease in the influx of chloride, such that influx and efflux were equalized.

Animals↗

Contribution of mucosal chloride to chloride in toad bladder epithelial cells.

Epithelial cells were scraped from the bladders of toads of the species Bufo marinus obtained from the Dominican Republic. These epithelial cells exchanged their chloride virtually completely with 36Cl i; the medium within 60 min. Of this chloride, about 93% came from the serosal medium. The approximately 20 mmole/kg dry wt of chloride which equilibrates with 36Cl in the mucosal medium was still present when choline replaced sodium in the medium in the presence of amiloride (10(-4) M) and was almost all readily removed by rapid washing of the mucosal surface immediately prior to analysis. These observations suggest that little chloride of mucosal origin is truly intracellular. This conclusion is supported by the fact that after vasopressin the increased cellular chloride was not of mucosal origin.

Animals↗

Light-driven chloride ion transport by halorhodopsin from Natronobacterium pharaonis. 2. Chloride release and uptake, protein conformation change, and thermodynamics.

The photocycle of the light-driven chloride pump, N. pharaonis halorhodopsin, is described by the scheme HR-->K--><==>L<==>N<==>O<==>HR'-->HR. From the chloride dependencies of the rate constants in this model we identify the N-->O and O-->HR' reactions as the steps where chloride release and uptake occur, respectively, during the transport. The dependencies of the rate constants on temperature describe a thermodynamic cycle in which enthalpy-entropy conversion occurs in the O-->HR' reaction. The dependencies of the rate constants on hydrostatic pressure indicate that a substantial volume decrease occurs at the L-->N reaction, a result of a large-scale conformational change. This is the opposite of the volume increase in the photocycle of the proton pump, bacteriorhodopsin, that is implicated in the access change of the active site during the transport and the passage of a proton from the cytoplasmic surface to the active site. The results together suggest a chloride transport mechanism, in which the equivalents of all the ion transfer steps in bacteriorhodopsin occur but in the reverse sense, so as to cause the extracellular-to-cytoplasmic translocation of a chloride ion instead of the cytoplasmic-to-extracellular transport of a proton.

Archaea↗

Analysis of vinylidene chloride and 1-chlorobutane in foods packaged with polyvinylidene chloride casing films by headspace gas chromatography/mass spectrometry (GC/MS).

A headspace gas chromatography/mass spectrometry method was developed for the simultaneous determination of vinylidene chloride and 1-chlorobutane in foods packaged with polyvinylidene chloride casing films. The solid foodstuff was homogenized with an equal mass of distilled water. The homogenate was incubated for 1 h at 90 degrees C in a sealed headspace vial, and the headspace gas was then analysed by gas chromatography/mass spectrometry in selected ion-monitoring mode using a bonded porous polymer-coated capillary column. The recovery rates of vinylidene chloride and 1-chlorobutane in foodstuffs were 94.5-103.9 and 85.8-120.3%, respectively. Among 13 samples tested, vinylidene chloride was detected at 0.001-0.020 microg g(-1) in 11 foodstuffs, and 1-chlorobutane was detected at 0.004-0.040 microg g(-1) in all 13 foodstuffs. Furthermore, vinylidene chloride was detected at 0.04 microg g(-1) in one casing film, and 1-chlorobutane was detected in all casing films. The results indicate that these compounds migrated from the casing films into the foodstuffs.

Butanes↗

Exposure to methylene chloride. III. Metabolism of 14C-labelled methylene chloride in rat.

The accumulation of methylene chloride and its metabolites in different organs and tissues was studied in an experimental series comprising 10 rats. Each rat was exposed for 1 h to radioactive methylene chloride (14C) in a concentration amounting to 1,935 mg/m3 in inspiratory air. Radioactive carbon atoms were found in the isolated carbon monoxide after exposure. There was also a close correlation between the activity of carbon monoxide extracted from the blood sample and the amount of carboxyhemoglobin (COHb) in the specimen. The largest concentration of methylene chloride and its metabolites per gram of tissue was found in white adipose tissue. This concentration had declined by more than 90% 2 h after exposure, whereas the concentration in the liver declined by about 25% during the same period. The amount accumulated in the brain displayed a decline of about 75% 2 h after exposure. Thus the examination showed that the increased concentration of COHb in the blood during exposure to methylene chloride is due to the metabolism of methylene chloride into carbon monoxide.

Adipose Tissue↗

[Determination of acetylene and vinyl chloride in hydrochloric acid from producing vinyl chloride by headspace gas chromatography].

A headspace gas chromatographic method was used for determining acetylene and vinyl chloride in hydrochloric acid from vinyl chloride production. Hydrogen chloride was neutralized by sodium hydroxide, so its effect on determining acetylene and vinyl chloride was eliminated. The headspace bottle was put in a water bath at 35 degrees C for 45 min. The GC column was a 2 m x 3 mm i.d. stainless steel tube packed with GDX-202 stationary phase. The column temperature was 140 degrees C. Injection volume was 1 mL. External standard method was used for quantitation. The relative standard deviation was 0.85% and the recoveries in the range of 30.0 micrograms/g-150 micrograms/g were 98.9%-103% for acetylene. The relative standard deviation was 1.4% and the recoveries in the range of 20.0 micrograms/g-100 micrograms/g were 98.8%-102% for vinyl chloride.

Acetylene↗

Liquid chromatographic determination of oestradiol in serum by pre-column derivatization with dansyl chloride or laryl chloride and peroxyoxalate chemiluminescence detection.

Column liquid chromatography with chemiluminescence detection is used to determine oestradiol in serum. Oestradiol is labelled by means of a two-phase derivatization procedure with either dansyl chloride or laryl chloride. After derivatization the excess reagent is removed on a short amino-bonded column: the sulphonyl chloride functional group reacts with the amino groups causing removal of the label; the oestradiol derivatives are not retained. Chromatography of oestradiol derivatives is performed with methanol-water mixtures as eluent. Chemical excitation is carried out by adding bis(2-nitrophenyl)oxalate and hydrogen peroxide dissolved in acetonitrile to the column eluate. Linearity is observed (r = 0.9998; n = 7) over at least three decades (10(-6)-10(-9) M) for both dansyl chloride and laryl chloride. A detection limit of 5 x 10(-10) M (50 fmol injected) has been achieved and the dansyl derivatization method has been applied to the determination of oestradiol in spiked serum.

Chromatography, High Pressure Liquid↗

Silver-silver chloride plunge electrode needles and chloriding monitor.

A plunge electrode is made from a hypodermic needle with one side cut open and multiple electrodes exposed from tip to base. A method for constructing chlorided silver electrode plunge needles is explained as well as problems associated with electrode chloriding. The small surface area of these electrodes makes empirical methods of chloriding difficult to use. A monitor was constructed for the testing and chloriding of a twelve-electrode plunge needle. This system continuously measures the impedance of the electrodes during chloriding.

Electric Conductivity↗

Quantitative analysis of chloride in brackish water: an application to the hyperchromic effect of copper(II) ion with chloride ion.

A new modified method was applied to the determination of chloride anion in brackish water by using a common copper(II) sulfate solution and a spectrophotometer. The result of the quantitative analysis demonstrated that chloride concentrations were 1.61% w/v and 1.74% w/v at ebb tide and flood tide, respectively, of the Muya River. On the other hand, chloride concentrations were 1.17% w/v at ebb tide and 1.65% w/v at flood tide of the Yoshino River. The new method proved that chloride concentration corresponded well with results from Mohr and conductive methods. Therefore, the newly developed method can be exploited as common means to measure chloride concentration in aqueous solutions. Moreover, it is also valuable for application to other types of environmental samples.

Journal Article↗

[Effectiveness of new quarternary ammonium chloride compounds against selected bacteria and fungi. XXI. Synthesis of alkoxymethyl-3,4-dimethyl- pyridine and 1-ethyloxymethyl-3-alkylthiomethylimidazole chlorides].

Syntheses and antibacterial properties of alkoxymethyl-3,4-dimethylpyridinium chlorides and 1-ethyloxymethyl-3-alkylthiomethylimidazolium chlorides are described. Alkoxymetgyl-3,4-dimethylpyridinium chlorides were synthetized by reacting 3,4-dimethylpyridine with chloromethyl alkyl ethers, while 1-ethyloxymethyl-3-alkylthiomethylimidazolium chlorides were obtained in reactions of 1-ethyloxymethylimidazol with chloromethyl alkyl sulfides. Antibacterial properties of the obtained compounds were tested on 13 strains of bacteria and fungi. Strong bacteriostatic activity was found to be displayed by iminium chlorides with octyloxymethyl, decyloxymethyl, octylthiomethyl and decylthiomethyl groups.

Anti-Bacterial Agents↗

Simulation of the bis-(penicillamine) enkephalin in ammonium chloride solution: a comparison with sodium chloride.

In order to quantify specific ion effects, a simulation study of bis(penicllamine) enkephalin, also known as DPDPE, has been performed in aqueous ammonium chloride solution and has been compared to a previous simulation of DPDPE in aqueous sodium chloride solution. Global thermodynamics have been calculated for a model system and the solution environment around DPDPE has been characterized. Associations of ions with DPDPE have been investigated. The observed differences between sodium chloride solution and ammonium chloride solution suggest that individual cations affect the solvation and peptide binding properties of a given anion.

Ammonium Chloride↗

Downregulated in adenoma gene encodes a chloride transporter defective in congenital chloride diarrhea.

Congenital chloride diarrhea (CLD) is a recessively inherited disorder characterized by massive loss of chloride in stool. We previously identified mutations in the downregulated in adenoma (DRA) gene in patients with CLD and demonstrated that DRA encodes an intestine-specific sulfate transporter. To determine whether DRA is an intestinal chloride transporter and how mutations affect transport, Xenopus oocytes were injected with wild-type and mutagenized DRA cRNA and uptake of Cl- and SO2-4 was assayed. Both Cl- and SO2-4 were transported by wild-type DRA and an outwardly directed pH gradient stimulated Cl- uptake, consistent with Cl-/OH- exchange. Among three mutants, C307W transported both anions as effectively as wild-type, whereas transport activity was lost in V317del and the double mutant identified in 32 of 32 Finnish CLD patients. We conclude that DRA is a chloride transporter defective in CLD and that V317del is a functional mutation and C307W a silent polymorphism.

Animals↗

Toxicity of vinyl chloride and poly(vinyl chloride): a critical review.

In 1974, vinyl chloride (VC) was first reported in the open scientific literature to induce angiosarcoma of the liver both in humans and in animals. Additional research has now demonstrated the carcinogenicity of VC to other organs and at lower concentrations. The target organs for VC now clearly include the liver, brain and the lung, and probably the lymphohematopoietic system. The evidence for a carcinogenic risk has been extended to jobs associated with poly(vinyl chloride) exposure. Cases of liver angiosarcoma have been reported among individuals employed in PVC fabrication facilities and an epidemiological study has demonstrated a significant association between exposure to PVC dust and the risk of lung cancer mortality. Cases of angiosarcoma of the liver also have been reported among individuals living in near proximity to vinyl chloride-poly(vinyl chloride) plants. An association between PVC dust and pneumoconiosis also has been demonstrated. On the basis of findings, prudent control of PVC dust in the industrial setting is indicated.

Environmental Exposure↗

[Effect of extracellular chloride concentration on deactivation kinetics of rat ClC-1 chloride channel].

The gating mechanism of ClC-1 chloride channel was studied in this paper by heteroexpression of rat wild type ClC-1 gene in Xenopus oocytes and by two-electrode voltage clamping technique. The deactivation gating kinetic parameters were obtained by applying two exponential fitting of the deactivating currents at various extracellular chloride concentrations. It was found that decrease in extracellular chloride concentration increased the fractional amplitude of fast deactivating component, and depressed the fractional amplitude of slow deactivating component accompanied by a decrease in fast and slow deactivating time constants. These results demonstrate that the deactivation kinetic parameters of ClC-1 are largely dependent on the extracellular chloride concentration, which induces changes in channel gating.

Animals↗

Delivery of paraldehyde in 5% dextrose and 0.9% sodium chloride injections through polyvinyl chloride i.v. sets and burettes.

The delivery of paraldehyde in 5% dextrose injection and 0.9% sodium chloride injection was studied, and the potential interaction between paraldehyde and plastic i.v. containers and sets was evaluated. Paraldehyde was mixed with either 5% dextrose injection or 0.9% sodium chloride injection in polyvinyl chloride (PVC) bags to form a 4% solution. The bags were fitted with standard i.v. administration sets or burettes with administration sets. The solutions were allowed to drip through the i.v. sets for six hours at room temperature. Samples were taken from the i.v. bag or burette and from the distal end of the i.v. sets at zero, two, four, and six hours. Paraldehyde concentrations were measured using a stability-indicating gas chromatographic method, and the presence of plasticizers was detected by a scanning ultraviolet spectrophotometer. The cumulative amount of paraldehyde delivered at the end of the administration set at six hours was 84% for 5% dextrose solutions in burettes, and 89% or 90% for all other solutions and i.v. sets. An ultraviolet-light-absorbing substance appeared in some of the samples, although a relationship between the presence of this substance and type of solution, time of sampling, or site of sample did not emerge. Particulate matter appeared after two hours in all burettes. Approximately 10%-16% of paraldehyde in 5% dextrose or 0.9% sodium chloride injection is lost when delivered from PVC i.v. bags through standard i.v. administration sets and burettes over a six-hour period.(ABSTRACT TRUNCATED AT 250 WORDS)

Drug Stability↗

Kinin-stimulated chloride secretion in mouse colon requires the participation of CFTR chloride channels.

The effect of lysylbradykinin on electrogenic chloride secretion in the epithelium of the mouse colon has been investigated. The peptide was active only when applied to the basolateral surface and its effects were inhibited by the B2 receptor antagonist, Hoe 140, also applied to the same surface. The chloride channel blocker, niflumic acid, also inhibited the response to kinin when added apically. Cyclo-oxygenase inhibition with piroxicam attenuated the responses to kinin, indicating involvement of prostaglandins in the responses. It is concluded that lysylbradykinin increases chloride secretion by acting via B2 receptors and, as with other tissues, brings about secretion through the agency of multiple messengers. In colonic epithelia from cystic fibrosis (CF) mice lysylbradykinin was without effect, suggesting that the final effector process involves apically located cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels.

Animals↗

Antagonistic effect of magnesium chloride on the nickel chloride-induced inhibition of DNA replication in Chinese hamster ovary cells.

The degree of inhibition of semiconservative DNA replication induced by nickel chloride (NiCl2) was analyzed by radiolabeled-thymidine incorporation alone or with cesium chloride (CsCl) density gradient centrifugation. The onset and duration of this Ni2+-induced inhibition was time- and concentration-dependent, but the degree of inhibition was not. A maximal reduction in the rate of DNA synthesis was observed within the first hour of treatment with 2.5 mM NiCl2, which was the highest noncytotoxic concentration utilized. After six hours, 500 microM and 1 mM as well as 2.5 mM NiCl2 all produced the same 50% to 60% reduction in [3H]-thymidine incorporation into DNA. The inhibitory effect of nickel ions on DNA synthesis was reversible. The rate of DNA synthesis following a 500 microM or 1 mM NiCl2 treatment began to increase after washout of nickel, but a six-hour exposure of cells to 2.5 mM NiCl2 produced a sustained 50% to 60% suppression of DNA synthetic activity for at least 36 hours. At all concentrations of NiCl2 used in this study, some inhibition of DNA synthesis persisted for at least 48 hours, but by 72 hours after treatment, the rate of [3H]-thymidine incorporation was actually 10% above the control. Examination of autoradiographic slides of cells treated with 2.5 mM NiCl2 for six hours demonstrated a 60% reduction of silver grains, but there was no preferential reduction in the quantity of grains in the nucleolus or any other region. Cesium chloride density gradient analysis of the replication of nucleolar DNA in cells treated with 2.5 mM nickel supported the autoradiographic findings. The inhibitory effect of NiCl2 on DNA replication was prevented by the addition of magnesium chloride (MgCl2) to cells maintained in a simple salts/glucose medium (SGM). This effect did not appear to be due to an antagonism of the cellular uptake of nickel by Mg2+, since the maximally effective dose of Mg2+ reduced 63Ni2+ uptake by no more than 25% while the inhibition of replication was completely reversed.

Animals↗

H4-isozyme of lactate dehydrogenase in a solution of sodium chloride-I. The molecular weight of H4-lactate dehydrogenase in relation to sodium chloride concentration, enzyme concentration and temperature.

1. The behavior of H4-lactate dehydrogenase in a solution of sodium chloride was studied with respect to its molecular weight. The molecular weight decreased as the concentration of sodium chloride increased. 2. On a controlled-pore glass column equilibrated by 0.5 M soldium chloride, H4-lactate dehydrogenase was found to have mol. wt 77,500. 3. In a low salt column (0.1 M sodium chloride or less), on the other hand, the molecular weight was found to be about 135,000. 4. Salt concentration dependent association-dissociation system of the enzyme was also observed by the sedimentation equilibrium method.

Animals↗