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At least 811 records · Page 45Linked to original sources
PubMed1987

Connective tissue responses to some heavy metals. I. Sodium loaded ion exchange beads as a control: histology and ultrastructure.

Ion exchange resin beads (Amberlite IR-120) were implanted into loose connective tissue as the vehicle for cations in both control and experimental studies. Beads were loaded with sodium for control purposes or with the metal of interest for subsequent experimental studies. When single control beads were implanted in the loose connective tissue of the rat pinna, they were well accepted by tissue and permitted rapid healing. The bead implantation initially produced minimal inflammatory disruption and subsequent repair at the bead-tissue interface which rapidly matured leaving no fibro-collagenous capsule. Some minor geometric rearrangement occurred in the alignment of the connective tissue to compensate for the physical presence of the bead. This system provides a valid control for studies of the effects of metal cations on tissue inflammation and repair--free from anionic complications, surface phenomena or systemic interference.

Animals↗
PubMed1979

Use of cholestyramine resin in the treatment of digitoxin toxicity.

Two case reports describing the treatment of digitoxin toxicity with cholestyramine resin are presented. Both female patients were receiving 100 microgram/day of digitoxin when toxicity occurred. In both patients, digitoxin was discontinued and hypokalemia was corrected. In patient 1, lidocaine hydrochloride and phenytoin sodium also were administered. Serum digitoxin levels were decreased from 43 ng/ml to 21.8 ng/ml and from 42 ng/ml to 29 ng/ml in patients 1 and 2, respectively, following administration of three 4-g doses of cholestyramine resin over a one-day period. Previous studies on the treatment of digitoxin intoxication with potassium chloride, phenytoin sodium, lidocaine hydrochloride, digitoxin-specific antibodies, colestipol hydrochloride and cholestyramine resin are discussed. Ion-exchange resins may be valuable adjuncts in the treatment of digitoxin intoxication but further studies of their utility are needed.

Aged↗
PubMed2004

Ion-exchange selectivity of anion exchange resin modified with polystyrenesulfonic acid.

In order to change the ion-exchange selectivity of anion-exchange resin, the surface of a gel-type anion exchange resin was modified with anionic polyelectrolyte, polystyrenesulfonic acid. Using this modified resin, the ion-exchange rate of nitrate was little decreased, but that of sulfate was evidently decreased. It is considered that the ion-exchange reaction of the multivalent anion is suppressed by the greater electrostatic repulsive force against the modification layer than that against the monovalent anion. Thus, this modified resin may be suitable for the selective separation of monovalent anions. The influence of the modified condition on the ion-exchange rate was examined. Furthermore, this modified resin was used to separate nitrate ions from sulfate ions in the aqueous solution.

Anion Exchange Resins↗
PubMed1982

Resin hemoperfusion for unconjugated bilirubin removal.

The application of an anionic macroreticular ion exchange resin, coated with a thin cross-linked albumin layer, as a hemoperfusion device for the removal of unconjugated bilirubin from the blood of hyperbilirubinemic newborn babies is reviewed. In vivo hemoperfusion runs with hyperbilirubinemic animal models - either by a choledocho-suprarenal vein shunt or by direct infusion of bilirubin into the vein - showed that a 40-ml resin column can remove some 20 mg bilirubin in 3 h. Hemoperfusion of female 8-14 kg baboons showed no significant effect of the column on blood chemistry and coagulation factors and repeated runs had no ill effects.

Adsorption↗
PubMed1976

Models for biological ion exchangers. I. Proton magnetic resonance studies of water structure in Bio-Rex 70.

Bio-Rex 70, a carboxylic acid cation exchanger, is studied as a biological ion-exchanger resin model for cellular cytoplasm. High-resolution proton magnetic resonance spectra of 1l ionic forms of Bio-Rex 70 are determined. From measured cation exchange capacities, water contents, and chemical shifts for the resin-phase water protons, the dependence of the chemical shift on the counter ion is calculated. The observed chemical shifts (Hz/geq/kg internal water, referred to the Ba2+ form) for each ionic form are: H+, --0.5; Li+, --0.2; Na+, 1.2; K+, 2; Rb+, 2.1; Ag+, --0.4; NH4+, --2.0; NMe4+, 1.2; NEt4+, 1.8; Mg2+, --2.0; Ca2+, --1.5; Sr2+, --0.6; Ba2+, 0.0 Zn2+, --2.3; Cd2+, --4.7; and La3+, --3.3. The results are in good agreement with earlier studies on Dowex 50, indicating that the carboxylate ion exchanger behaves like a concentrated polyelectrolyte. The widths at half-height for the internal water peaks of the polyvalent forms are quite large, ranging from 40 to 100 Hz.

Cation Exchange Resins↗
PubMed1999

Simplified sample preparation for the analysis of oligonucleotides by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry.

Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) for the analyses of oligonucleotides has generally been carried out using negative ionisation conditions, usually following ammonium ion-exchange chromatography and the addition of ammonium buffers to the MALDI matrix. The molecular ion region is complex, due to the varying degrees of ammoniation of the phosphate backbone of the oligonucleotide. This gives rise to an overall decrease in sensitivity compared with similar size peptides and can cause ambiguity of assignment of the relative molecular mass of the sample. This study describes the use of H(+) ion exchange resin in situ as the means of removing alkali metal ions from the phosphate backbone of the oligonucleotide. An increase in resolution, sensitivity and identification of the molecular species is reported, with little or no difference in sensitivity observed between positive or negative ionisation spectra. This method is now used for routine screening of synthetic oligonucleotides with a gain in sensitivity of 1-2 orders of magnitude compared with previous methods, and mass assignment errors of +/-0.1% are routinely recorded for externally calibrated data.

Ion Exchange Resins↗
PubMed2005

Removal of Cr(VI) from aqueous solution by two Lewatit-anion exchange resins.

The sorption of hexavalent chromium, Cr(VI), from aqueous solutions on macroporous resins containing tertiary amine groups (Lewatit MP 62 and Lewatit M 610) was studied at varying Cr(VI) concentrations, adsorbent dose, pH, contact time and temperatures. The concentration of chromium in aqueous solution was determined by inductively coupled plasma spectrometry (ICP-AES). Batch shaking sorption experiments were carried out to evaluate the performance of Lewatit MP 62 and Lewatit M 610 anion exchange resins in the removal of Cr(VI) from aqueous solutions. The ion-exchange process, which is pH dependent, shows maximum removal of Cr(VI) in the pH range 2-6 for an initial Cr(VI) concentration of 100 ppm. The sorption increases with the decrease in pH and slightly decreases with the increase in temperature. Both ion exchangers had high bonding constants with Lewatit M 610 showing stronger binding. It was observed that the maximum adsorption capacity of 0.40 mmol of Cr(VI)/g for Lewatit MP 62 and 0.41 mmol of Cr(VI)/g for Lewatit M 610 was achieved at pH of 5.0. The thermodynamic parameters (free energy change, DeltaG degrees ; enthalpy change, DeltaS degrees ; and entropy change, DeltaH degrees ) for the sorption have been evaluated. The rise in temperature caused a slight decrease in the value of the equilibrium constant (Kc) for the sorption of Cr(VI) ion. The sorption of Cr(VI) on the resin was rapid during the first 15 min and equilibrium was found to be attained within 30 min. The sorption of Cr(VI) onto the resins followed reversible first-order rate kinetics. Such ion exchange resins can be used for the efficient removal of chromium from water and wastewater.

Adsorption↗
PubMed2006

Environmentally benign hardness removal using ion-exchange fibers and snowmelt.

Many industrial unit operations and unit processes require near-complete removal of hardness to avoid scaling in heat-transfer equipment, fouling in membranes, and high consumption of detergents and sequestering chemicals in cooling and wash water. Lime softening and cation exchange are the most commonly used processes practiced to date for hardness removal. Herein, we report and discuss the results and attributes of a new hardness removal process using ion-exchange fibers (IX-fibers). Most importantly, the process uses harvested snowmelt (or rainwater) as the regenerant chemical along with sparged carbon dioxide. Consequently, the spent regenerant does not contain a high concentration of aggressive chemicals such as sodium chloride or acid like traditional ion-exchange processes nor does the process produce voluminous sludges similar to lime softening. The bulk of carbon dioxide consumed during regeneration remains sequestered in the aqueous phase as alkalinity. IX-fibers form the heart of the process. They are essentially thin cylindrical polymeric strands 10-20 microm in diameter. The weak-acid carboxylate functional groups reside near to the surface of these cylindrical fibers. Low intraparticle diffusional resistance is the underlying reason IX-fibers are amenable to efficient regeneration with snowmelt sparged with carbon dioxide. When the carbon dioxide partial pressure is increased to 6.8 atm, over 90% calcium desorption efficiency is obtained. On the contrary, commercial weak-acid ion-exchange resins in spherical bead forms are ineffective for regeneration with carbon-dioxide-sparged snowmelt due to extremely slow ion-exchange kinetics involving counter-transport of Ca2+ and H+.

Acids, Noncarboxylic↗
PubMed1967

Determination of serum thyroxine using a resin sponge technique.

A method is described for the determination of serum thyroxine using ion-exchange resin sponges. The principle is based on the use of protein-binding sites and part of the technique is similar to the Triomet resin uptake test. An isotope extraction recovery procedure is incorporated in the method. Studies of factors influencing the analysis are reported and the results of tests of accuracy, precision, and specificity are presented. Serum thyroxine iodine values are compared with protein-bound iodine estimations. The values found in health and disease are similar to the results of previous workers. The specificity of the analysis represents a considerable advantage over protein-bound iodine determinations since no interference is caused by iodides, iodine-containing contrast media, mercurial diuretics, mono-iodotyrosine, di-iodotyrosine, di-iodothyronine, and also tri-iodothyronine in physiological amounts. Therapy with diphenylhydantoin and tri-iodothyronine will tend to depress protein-bound iodine levels and thyroxine values are similarly influenced.

Humans↗