Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ION EXCHANGE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources
PubMed1980

Sorption of cholesterol and other bile components on ion-exchangers in vitro, and their influence on the cholesterol level in human serum in vivo.

The sorption of bile acids, bilirubin, bilirubin glucuronates and cholesterol on ion-exchange resin is described. After some successful attempts of sorption of these substances from human and animal bile in vitro, this exchanger has been used in human therapy. Positive results obtained showed the usefulness of the method. The purpose of the experiments was to study the usefulness of ion-exchangers for sorption of bile components of bile acids, bilirubin, bilirubin glucuronates and cholesterol. First sorption was carried out on human and animal bile, on Zerolit-FS-ip, in cycles (OH-) and (Cl-), by passing through glass columns downwards and some of them by mixing the bile with ion-exchange resin. Zerolit FS-ip is an organic sorbent, a scavenger, a strongly basic macroporous, anion exchanger. Positive results of these sorptions indicated the possibility of using this method in therapy of disturbed lipid conditions.

Adult↗
PubMed1999

Interprotein metal ion exchange between cadmium-carbonic anhydrase and apo- or zinc-metallothionein.

The ligand substitution reactions of cadmium-carbonic anhydrase with EDTA and pyridine-2,6-dicarboxylic acid were compared with one in which rabbit apometallothionein was the competing metal-binding agent. This last reaction occurred more rapidly than the other two at a much smaller ratio of competing ligand to Cd-carbonic anhydrase. It was characterized as a second-order reaction, first-order in Cd-carbonic anhydrase and in apometallothionein, having a rate constant of 5.8 +/- 0.1 M-1 s-1 at 25 degrees C and pH 7.4 in Tris.HCl buffer and 0.1 M KCl. At 25 degrees C, Zn7-metallothionein also exchanged metal ions with Cd-carbonic anhydrase with a rate constant of 0.33 +/- 0.02 M-1 s-1 to reconstitute enzymatically active protein. Cd-carbonic anhydrase reacted within the time of mixing with the peptide sequence 49-61 of rabbit metallothionein 2 which contains four cysteinyl residues, leading to the exchange of most of the Cd2+ into the peptide. At pH 7.4 and 25 degrees C, Cd2+ has higher affinity for apometallothionein than for the apo-peptide.

Amino Acid Sequence↗
PubMed1976

Physicochemical properties of a liquid ion exchanger microelectrode and its application to biological fluids.

Double-barreled potassium or chloride ion-selective microelectrodes were constructed using a liquid ion exchanger. Technical details of the fabrication of double-barreled microelectrodes, having a PD sensor as one barrel and an ionic sensor as the other, are described. The sensitivity of K+ or CI- ion-selective microelectrodes exhibited an approximately Nernstian response over a temperature range of 7 degrees-37 degrees C, and the electromotive force (EMF) was stable within +/- mV for a few hours. The rise time was less than 1 sec. The effect of pH on the electrode response was negligible over a physiological range of pH 5.6 to 7.8. The selectivity constants of the K+ microelectrode to other cations were 0.011 for Na+, 0.200 for NH+4, and less than 0.002 and 0.001 for Ca++ and Mg++, respectively, while that of the CI- microelectrode was 0.067 for HCO-3. Glucose or urea has no effect on the EMF. Protein has a significant effect on ion exchanger membrane only when the concentration of the tested ion is low and protein is high. On the basis of this background the determination of K+ and CI- activity was carried out both in vivo and in vitro on several biological samples, such as serum, tissue and cellular fluids, and other protein-containing fluids. The values obtained with the microelectrode were consistent with those obtained with the other conventional methods or with the current theory on electrolyte solutions. These results were taken to assure the practical application of these electrodes to biological studies in many fields.

Animals↗
PubMed1997

Comparative quantitative analysis of sucrose and related compounds using ion exchange and reverse phase chromatographic methods.

Two analytical methods of sugar determination, namely ion exchange chromatography on an anionic resin coupled with electrochemical detection, and reverse phase chromatography on Nucleosil-NH2 resin equipped with a light scattering detector were tested and compared as regards their rapidity, sensitivity and accuracy with sucrose, fructose, glucose, raffinose, maltose, arabinose, fucose, rhamnose and xylose. Excellent resolution and highly reproducible results were obtained in both cases. Greater sensitivity up to the picomolar range was possible however only with ion exchange chromatography. Reverse phase chromatography was successfully applied to the time course of sucrose hydrolysis under chemical (acid) and enzymatic (invertase) conditions. The hydrolysis was monitored by determining sucrose degradation and the corresponding formation of glucose and fructose.

Carbohydrates↗
PubMed1989

Determination by ion-exchange chromatography of trifluoroacetic acid as a biliary metabolite of isoflurane in the rabbit.

The optimal composition of eluant for trifluoroacetic acid (TFAA) analysis by ion-exchange chromatography was determined and a preliminary study to detect TFAA, a metabolite of isoflurane, in bile of rabbits during and after inhalation of isoflurane was made. The optimal composition of eluant for TFAA analysis by ion-exchange chromatography was determined to be a solution of 2mM Na2CO3 and 4mM NaHCO3. Rabbits were divided into 4 groups; A group: 1 hr inhalation of 2% isoflurane, B group: 2 hr inhalation of 2% isoflurane, C group: 2 hr inhalation of 3% isoflurane, and D group: 2 hr inhalation of 4% isoflurane. The maximum biliary TFAA concentration in groups A, B, C and D averaged 17.5 +/- 1.4 microM (mean +/- S.D.) at 105 min, 37.1 +/- 11.5 microM at 315 min, 54.5 +/- 9.4 microM at 585 min and 34.4 +/- 12.1 microM at 555 min after termination of inhalation. Cumulative excreted amounts of biliary TFAA for 20 hours were 746 nmols in A group (8 hours), 3,421 nmols in B group, 6,582 nmols in C group and 3,267 nmols in D group. Half-lives of biliary excreted TFAA were 63 min, 325 min, 478 min and 546 min, respectively. These results showed that ion-exchange chromatography is more convenient for detecting TFAA as a metabolite of isoflurane than isotachophoresis, gas chromatography, paper chromatography and thin layer chromatography and that TFAA was determined as a biliary metabolite of isoflurane in the rabbit.

Animals↗
PubMed2004

Ion-exchange fibers and drugs: a novel device for the screening of iontophoretic systems.

The objective of this study was to theoretically model and experimentally measure the extent of drug release from ion-exchange fibers. The release was measured as a function of current density and NaCl concentration using a novel iontophoretic cell. The fibers tested contained weak carboxylate (-COOH) ion-exchange groups. The cationic model drugs tacrine and metoprolol were chosen on the basis of previous research, where tacrine had the lowest release rate and metoprolol the highest release rate. An in-house designed three compartment test cell was developed to test the suitability of drugs for iontophoretic drug delivery. In this cell, the anode and the drug containing ion-exchange fiber compartments were separated with a Nafion ion-selective membrane, while the fiber and the return electrode compartments were separated with a porous membrane. Tacrine proved to be a good drug candidate for this system as the release of the tacrine from the device was controllable with salt concentration and current density. Metoprolol release from the device was, however, not controllable.

Chromatography, Ion Exchange↗
PubMed2006

Ion-exchange chromatography used to isolate a spermadhesin-related protein from domestic goat (Capra hircus) seminal plasma.

Mammalian seminal plasma contains among others, proteins called spermadhesins, which are the major proteins of boar and stallion seminal plasma. These proteins appear to be involved in capacitation and sperm-egg interaction. Previously, we reported the presence of a protein related to spermadhesins in goat seminal plasma. In the present study, we have further characterized this protein, and we propose ion-exchange chromatography to isolate this seminal protein. Semen was obtained from four adult Saanen bucks. Seminal plasma was pooled, dialyzed against distilled water and freeze-dried. Lyophilized proteins were loaded onto an ion-exchange chromatography column. Dialyzed-lyophilized proteins from the main peak of DEAE-Sephacel were applied to a C2/C18 column coupled to an RP-HPLC system, and the eluted proteins were lyophilized for electrophoresis. The N-terminal was sequenced and amino acid sequence similarity was determined using CLUSTAL W. Additionally, proteins from DEAE-Sephacel chromatography step were dialyzed and submitted to a heparin-Sepharose high-performance liquid chromatography. Goat seminal plasma after ion-exchange chromatography yielded 6.47 +/- 0.63 mg (mean +/- SEM) of the major retained fraction. The protein was designated BSFP (buck seminal fluid protein). BSFP exhibited N-terminal sequence homology to boar, stallion and bull spermadhesins. BSFP showed no heparin-binding capabilities. These results together with our previous data indicate that goat seminal plasma contains a protein that is structurally related to proteins of the spermadhesin family. Finally, this protein can be efficiently isolated by ion-exchange and reverse-phase chromatography.

Animals↗
PubMed1985

Separation of various calmodulins, calmodulin tryptic fragments, and different homologous Ca2+-binding proteins by reversed-phase, hydrophobic interaction, and ion-exchange high-performance liquid chromatography techniques.

Reversed-phase, hydrophobic interaction, and ion-exchange high-performance liquid chromatography techniques have been used to separate different Ca2+-binding proteins and their proteolytic fragments. An alkali-stable ion-exchange column permitted the baseline separation of calmodulin fragments which differed only by one to three charged amino acids. The new hydrophobic interaction chromatography system displayed a high-resolution power separating calmodulins from different sources and calmodulin fragments obtained by trypsin proteolysis. The properties and advantages of the different systems are discussed in detail.

Animals↗
PubMed1999

[Purification of outer membrane proteins in Pseudomonas aeruginosa by high performance ion-exchange liquid chromatography].

Pseudomonas aeruginosa PAO1 was used in this study. Isolation of outer membrane was accomplished by treating the cell envelope with EDTA and lysozyme, followed by centrifugation. The outer membrane (10 mg of protein) was mixed with 34 mmol/L octyl beta-glucoside-5 mmol/L EDTA-10 mmol/L Tris-HCl (pH 8.0) and subjected to supersonic oscillation for 2 min. The centrifuged supernatant (100 kgf for 30 min at 20 degrees C) was applied onto a DEAE ion-exchange high performance liquid chromatographic column (TSK gel-DEAE-5PW column, 0.75 cm x 7.5 cm i.d.) that was equilibrated with a solution of 10 mmol/L Tris-HCl buffer (pH 8.0) containing 2.5 mmol/L beta-C12E8 and 1 mmol/L EDTA. The column was washed with the same solution and eluted with a linear gradient of 0-0.5 mol/L NaCl in the same solution and fractions A, B, C were collected. Proteins in these fractions were analyzed by SDS-polyacrylamide gel electrophoresis and quantified by the method of Lowry et al. Protein E(Mr 43,000), G(Mr 25,000) and H (Mr 19,000) flowed through the column without adsorption in fraction A. Protein C(Mr 70,000), D(Mr 46,000) and a small amount of F (Mr 34,000) were eluted in fraction B. Fraction A was concentrated with ultrafiltration and applied again onto a DEAE ion-exchange HPLC column equilibrated with 10 mmol/L Tris-HCl buffer, pH 8.0, containing 34 mmol/L beta-C12E8 and 1 mmol/L MgCl2. Fraction B was subjected to DEAE ion-exchange HPLC column in the presence of EDTA. This fraction was then applied onto a DEAE ion-exchange HPLC column equilibrated with 10 mmol/L Tris-HCl buffer, pH 8.0, containing 34 mmol/L octylglucoside and 1 mmol/L EDTA. By these procedures protein C, D and E were purified to apparent homogeneity as judged by SDS-PAGE. In this work, we purified the outer membrane proteins of Pseudomonas aeruginosa, and used a new technique selectively solubilizing the cytoplasmic membrane with sodium lauryl sarcosinate for isolating the outer membrane proteins of Pseudomonas aeruginosa because of its relative simplicity.

Adhesins, Bacterial↗
PubMed2006

Radiotracer measurements of protein mass transfer: kinetics in ion exchange media.

We describe a method to measure protein mass transfer kinetics in ion exchange adsorbents for preparative chromatography based on the use of radioactively labeled protein. The method was developed and evaluated using lysozyme as a test protein with the three commercial strong-acid cation exchangers SP-Sepharose-FF, SP-Sepharose-XL, and S-HyperD. Iodination with 125I was used to label the protein, which was added in trace amounts (approximately 0.1%) to an unlabeled protein solution. The solution was recirculated through a shallow bed of the adsorbent particles and the radioactivity accumulated in the bed measured with a gamma-counter as a function of time. Radiotracer-based kinetics measurements were found to be in good agreement with results obtained with a conventional shallow-bed technique, provided that freshly labeled protein solutions were used. The method has advantages in terms of simplicity, ability to deal with adsorption from complex mixtures, and the potential for measurements under tracer diffusion conditions. Kinetics results obtained for the three different stationary phases were generally consistent with previous studies. Protein mass transfer can be described by a pore diffusion model with a nearly salt-independent pore diffusivity for SP-Sepharose-FF and by a homogeneous diffusion model with a saltindependent adsorbed phase diffusivity for S-HyperD. However, it appears that a more complex model, accounting for parallel pore and surface diffusion, is needed to describe protein mass transfer in SP-Sepharose-XL. The modeling results were found to be correlated with the apparent pore sizes determined by inverse SEC.

Chromatography, Ion Exchange↗
PubMed2003

Spent ion exchange resin-its treatment from the point of view of safe disposal.

Ion exchange process is one of the treatment methods for radioactive waste. The resin becomes no longer useful after number of cycles of usage. At the same time the regenerated resin cannot be considered as non active waste for disposal. Hence it is felt necessary that the regenerated resin is treated in a fashion so as to result in a form which can be considered as inactive material. It is possible to convert this spent resin into multivalent ionic form which are generally non leachable, thus providing the necessary properties for meeting the disposal criteria. Studies were carried out for the exchange of radioactive ions on these resins with ions like Al3+, Sn4+, Pb2+ and Fe3+ etc. The studies included leachability aspects, exchange with other active ions, thermal characteristics, compressive strength of the cement blocks loaded with the resin etc. Our studies indicated that the order of the stability of the resin with respect to properties like leachability, exchange properties etc. follow the trend as follows: Sn4+ > Pb2+ > Al3+ > Fe3+.

Compressive Strength↗
PubMed2005

Ion-exchanged glass waveguides with low birefringence for a broad range of waveguide widths.

Optical communications networks require integrated photonic components with negligible polarization dependence, which typically means that the waveguides must feature very low birefringence. Recent studies have shown that waveguides with low birefringence can be obtained, e.g., by use of silica-on-silicon waveguides or buried ion-exchanged glass waveguides. However, many integrated photonic circuits consist of waveguides with varying widths. Therefore low birefringence is consequently required for waveguides having different widths. This is a difficult task for most waveguide fabrication technologies. We present experimental results on waveguide birefringence for buried silver-sodium ion-exchanged glass waveguides. We show that the waveguide birefringence of the order of 10(-6) for waveguide mask opening widths ranging from 2 to 10 microm can be obtained by postprocessing the sample through annealing at an elevated temperature. The measured values are in agreement with the values calculated with our modeling software for ion-exchanged glass waveguides. This unique feature of ion-exchanged waveguides may be of significant importance in a wide variety of integrated photonic circuits requiring polarization-independent operation.

Journal Article↗
PubMed1991

Interfacial thermodynamics of protein adsorption, ion co-adsorption and ion binding in solution. II. Model interpretation of ion exchange in lysozyme chromatography.

In this paper we present a model for the ion exchange effects in protein adsorption. The model is applied to chromatography of lysozyme on strong cation exchanger 'mono S'. The experimental and general thermodynamic aspects have been discussed in Part 1, the preceding paper. The main modelling assumptions are (i) the charge regulation is confined to the small layer of contact between adsorbed protein and exchanger surface, (ii) the contact layer as a whole is electroneutral and (iii) the number of protein acid/base groups and exchanger surface acid groups which participate in the ion exchange is proportional to the area of the contact layer. The model is fitted to the experimental data by adjustment of only two or three parameters. The experimental co-adsorption numbers are very well reproduced. A few conspicuous features emerge: (i) the number of protein acid/base groups and exchanger surface acid groups in the contact layer varies with the medium conditions, such that the number is higher when the interaction between protein and exchanger surface is stronger. (ii) There is indirect evidence for structural alterations in the upper layers of the exchanger surface: the adsorbed protein is probably partly 'buried' in the surface.

Journal Article↗
PubMed2005

The study of various parameters affecting the ion exchange of Cu2+, Zn2+, Ni2+, Cd2+, and Pb2+ from aqueous solution on Dowex 50W synthetic resin.

A gel resin containing sulfonate groups (Dowex 50W) was investigated for its sorption properties towards copper, zinc, nickel, cadmium and lead metal ions. The use of selective ion exchange to recover metals from aqueous solution has been studied. The ion exchange behavior of five metals on Dowex 50W, depending on pH, temperature, and contact time and adsorbate amount was studied. Experimental measurements have been made on the batch sorption of toxic metals from aqueous solutions using cation exchanger Dowex 50W. The maximum recoveries (about 97%) Cu(2+), Zn(2+), Ni(2+), Cd(2+) and (about 80%) Pb(2+) were found at pH ranges 8-9. The amount of sorbed metal ion was calculated as 4.1, 4.6, 4.7, 4.8, and 4.7mequiv./gram dry resin for Pb(2+), Cu(2+), Zn(2+), Cd(2+), and Ni(2+), respectively. The precision of the method was examined at under optimum conditions. Selectivity increased in the series: Pb>Cd>Cu>Zn>Ni. It has been observed that, selectivity of the -SO(3)H group of the resin increases with atomic number, valance, degree of ionization of the exchanged metals. The equilibrium ion exchange capacity of resin for metal ions was measured and explored by using Freundlich and Langmuir isotherms. Langmuir type sorption isotherm was suitable for equilibrium studies.

Hydrogen-Ion Concentration↗
PubMed1993

Peritubular Na-K exchange ion pump in maleate-treated frog kidney proximal tubular cells.

1. After perfusion of isolated frog kidneys for 1 hr with 10(-3) or 10(-2) M maleate Ringer, the peritubular membrane potential gradually declined in a dose-dependent manner. 2. The ouabain-like effects of maleate on cell Na and K activities were dose-dependent and smaller than the effects of zero K or 10(-4) M ouabain. Intracellular pH was not altered in the presence of 10(-2) M maleate. 3. The driving force for Na entry into the cell was reduced, respectively, to 81.4 and 58.4% (of control) in the presence of 10(-3) and 10(-2) M maleate. 4. There was no histochemically detectable inhibition of proximal tubule Na-K ATPase activity during 3 hr of perfusion with 10(-2) M maleate.

Animals↗