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At least 973 records · Page 54Linked to original sources
PubMed1977

Pathology of structured water and associated cations in cells (ther tissue damage syndrome) and its medical treatment.

Modern experimental evidence indicates that the cell should be regarded as analogous to an ion exchanger resin granule with structured water in the interstices and with potassium and sodium ions associated with fixed negative charges on the protein matrix. In tissues damaged by disease or trauma, a similar set of changes in properties of cell cations and water is to be expected, for which a similar set of therapies is appropriate. Tissue damage causes a configurational change of the protein matrix from the normal to the damaged state. This leads to loss of association preference for potassium vs. sodium ions and to loss of water structuring, resulting in replacement of cell potassium by sodium and abnormal uptake of water by the cell. Appropriate therapies for reestablishment of the normal configurational state of the proteins of the cell are reestablishment of normal cell ATP production, for which prostaglandin PGBx is the rational approach, plus diets or drugs that decrease sodium and/or increase potassium concentrations in the body. Partial normalization of cell protein configuration by digitalis compounds may also be possible.

Adenosine Triphosphate↗
PubMed1982

[Investigations in Bioavailability of resinates as peroral retard drug dosage forms. Part 1: Pharmaceutical availability of dihydrocodein-resinates (author's transl)].

The dissolution rate constants of dihydrocodein in two retard drug dosage forms based on synthetic ion exchange resin were determined with four dissolution methods. The usage of the flow cell, rotationsdisk method and half-change method with a new dissolution model gave comparable results. Using the paddle apparatus the dissolution is very quick. There is only a small influence on the dissolution rate by the pH. A higher ionic strength of the dissolution medium increases the dissolution rate.

Biological Availability↗
PubMedDate not supplied

[Preparation and properties of acid proteinase from Aspergillus awamori].

From the culture liquid filtrate of Aspergillus awamori 78-2 a preparation of acid proteinase was isolated and its properties were described. This producer was shown to have a peculiar capacity of synthesizing under submerged conditions extracellular acid proteinase as the sole proteolytic enzyme. The preparation of acid proteinase showed a comparatively high hydrolyzing capacity. Under optimal conditions the enzyme degraded hemoglobin and albumin almost completely. The possibility of purifying and concentrating acid proteinase on the ion-exchange resin KB 51 X 2 was explored.

Aspergillus↗
PubMedDate not supplied

[Chromatographic analysis of water-soluble vitamins. I- Chromatographic behaviour of water-soluble vitamins on Aminex resins (author's transl)].

The most important water-soluble vitamins are quantitatively determined by high pressure chromatography using porous ion exchange resins. Thiamine and Riboflavine are separated by a cation exchange resin Aminex A5 using 0.3 M KCI in 0.1 M potassium phosphate pH 8.0 buffer as mobile phase; pyridoxamine, pyridoxol, pirydoxal and nicotinamide are successfully chromatographated on the same type of cationic resin using a linear gradient both of pH and ionic strength as mobile phase. Anionic vitamins like L-Ascorbic Acid and Nicotinic Acid are separated on Aminex A14 at acidic values of pH, using isocratic conditions of the ionic modifier. Under the described experimental conditions, the reproducibility of VR, RS and peak area are of 2.5% and 3% respectively. The sensitivity relative to the vitamins tested ranges from 100 to 250 ng.

Chromatography, High Pressure Liquid↗
PubMed1997

The role of nitric oxide in cancer. Improved methods for measurement of nitrite and nitrate by high-performance ion chromatography.

The short lifetime of nitric oxide (NO) in vivo impedes its quantitation directly; however, the determination of nitrite and nitrate ions as the end-products of NO oxidation has proven a more practical approach. High-performance ion chromatographic analysis of nitrite in biological fluids is hampered by the large amount of chloride ion (up to approximately 100 mmol/l) which results in insufficient peak resolution when utilizing conductimetric detection. Analysis of both anions in small sample volumes is also constrained by the need to minimise sample handling to avoid contamination by environmental nitrate. We report a means to remove Cl- ions from small sample volumes using Ag+ resin which facilitates quantitation of either nitrite and nitrate anions in biological samples, using silica or polymer based ion-exchange resins with conductimetric or electrochemical and spectrophotometric detection. Including a reversed-phase guard column before the anion-exchange guard and analytical column also greatly extends column lifetime.

Animals↗
PubMed2006

Comparative studies on the adsorption of Cr(VI) ions on to various sorbents.

The adsorption of Cr(VI) ions onto various sorbents (chitin, chitosan, ion exchangers; Purolite CT-275 (Purolite I), Purolite MN-500 (Purolite II) and Amberlite XAD-7) was investigated. Batch adsorption experiments were carried out as a function of pH, agitation period and concentration of Cr(VI) ions. The optimum pH for Cr(VI) adsorption was found as 3.0 for chitin and chitosan. The Cr(VI) uptake by ion exchangers was not very sensitive to changes in the pH of the adsorption medium. The maximum chromium sorption occurred at approximately 50 min for chitin, 40 min for Purolite II and 30 min for chitosan, Purolite I and Amberlite XAD-7. The suitability of the Freundlich and Langmuir adsorption models were also investigated for each chromium-sorbent system. Adsorption isothermal data could be accurately interpreted by the Langmuir equation for chitosan, chitin, Purolite I and Purolite II and by the Freundlich equation for chitosan, chitin and Amberlite XAD-7. The chromium(VI) ions could be removed from the sorbents rapidly by treatment with an aqueous EDTA solution and at the same time the sorbent regenerated and also could be used again to adsorb by heavy metal ions. The results showed that, chitosan, which is a readily available, economic sorbent, was found suitable for removing chromium from aqueous solution.

Acrylic Resins↗
PubMed2001

Preparation and in vivo evaluation of mucoadhesive microparticles containing amoxycillin-resin complexes for drug delivery to the gastric mucosa.

In this work, microparticles consisting of amoxycillin-loaded ion-exchange resin encapsulated in mucoadhesive polymers (polycarbophil and Carbopol 934) were prepared with the aim of increasing the efficacy of amoxycillin in the treatment of peptic ulcers by achieving targeted delivery to the gastric mucosa and prolonged drug release. An oil-in-oil solvent evaporation technique was conveniently modified in order to obtain polymer microparticles containing multiple amoxycillin-resin cores. Polycarbophil microparticles were spherical, Carbopol 934 microparticles irregular. In vitro release of amoxycillin was rapid with or without a polymer coating. Gastrointestinal transit in rats was investigated by fluorescence microscopy using particles loaded with fluorescein instead of amoxycillin: gastric residence time was longer, and the distribution of the particles on the mucosa apparently better, without any polymer coating.

Acrylic Resins↗
PubMed2000

The preparation and characterization of an immobilized l-glutamic decarboxylase and its application for determination of l-glutamic acid.

This paper is to study the preparation and characterization of an immobilized L-glutamic decarboxylase (GDC) and develop a sensitive method for the determination of L-glutamate using a new biosensor, which consists of an enzyme column reactor of GDC immobilized on a novel ion exchange resin (carboxymethyl-copolymer of allyl dextran and N.N'-methylene-bisacrylamide CM-CADB) and ion analyzer coupled with a CO(2) electrode. The conditions for the enzyme immobilization were optimized by the parameters: buffer composition and concentration, adsorption equilibration time, amount of enzyme, temperature, ionic strength and pH. The dynamic response of Na(2)HPO(4)-citric acid buffer system selected is much better than that of the others, 0.10 M HAc-0.10 M NaAc and 0.10 M sodium citrate-0.10 M citric acid. The initial rate of the enzyme reaction v(0) in this buffer system is 1.76 mol. l(-1) min(-1), moreover, the rate of the enzyme reaction appears linear in the first 4 min. The optimum adsorption equilibrium time is around 6 h. The amount of enzyme adsorbed on CM-CADB resin affects the response to substrate L-glutamic acid, the widest range of linearity is obtained with over 30 mg (GDC)/g(resin). The GDC activity immobilized on CM-CADB reaches a maximum when the immobilization temperature was kept around 40 degrees C. pH was kept at 4.4 when measuring the activity of the immobilized GDC. No variation of the activity of immobilized GDC is observed when the capacity is over 2.5 meq/g.(CM-CADB resin). The properties of the immobilized enzyme on CM-CADB were characterized. No significant improvement can be achieved when the substrate concentration exceeds 12.00 mmol/l, where the activity of immobilized GDC is equal to 1.58 mmol/l.min.g. The optimum pH is found to be 5.2, which changes 0.2 unit, comparing with that of the free GDC (5.0). The optimum temperature is found to be around 48 degrees C, which is lower than that of free GDC (55 degrees C). The critical temperature of the free GDC and the immobilized GDC is approximately 50 degrees C and 45 degrees C, respectively. The half-life of the activity is 127 days when the immobilized enzyme was stored in the cold (4 degrees C). An immobilized GDC enzyme column reactor matched with a flow injection system-ion analyzer coupled with CO(2) electrode-data collection system made up the original form of the apparatus of biosensor for determining of L-glutamic acid. The determination conditions are that the buffer solution is 0.10 M Na(2)HPO(4)-0.05 M citric acid at pH 4.4 and t = 37 degrees C. The limit of detection is 1.0 x 10(-)(5) M. The linearity response is in the range of 5 x 10 (-2) - 5 x 10 (-5) M. The equation of linear regression of the calibration curve is y = 43.3x + 181.6 (y is the milli-volt of electrical potential response, x is the logarithm of the concentration of the substrate of L-glutamic acid). The correlation coefficient equals 0.99. The coefficient of variation equals 2.7%.

Journal Article↗
PubMed1979

Quantitative gas-liquid chromatography of neutral sugars in human serum glycoproteins. Fucose, mannose, and galactose as predictors in ovarian and small cell lung carcinoma.

A precise and accurate gas-liquid chromatographic (GLC) method has been developed for the quantitative analysis of the neutral sugars L-fucose (6-deoxygalactose), mannose, galactose, and glucose in ethanol precipitates of human serum proteins. The chromatographic conditions and sample preparation resulted in short analysis time (20 min per run) and made routine analyses practicable (twelve samples per day). The alditol acetate derivatization yielded single derivatives for each sugar. Complete separation was achieved on a 2.0 m X 2 mm I.D. column with 2.0% Silar-7CP on Chromosorb W AW 80--100 mesh. The results of hydrolysis showed that the release of fucose and galactose preceded the release of mannose. Hydrolysis with AG 50 W-X8 (H+) ion-exchange resin in 0.5 N HCl at 100 degrees for 7 h optimized glycosidic bond cleavage with only minimal destruction of fucose, mannose and galactose. A combination of strong cation- and anion-exchange resin columns was used to remove chromatographic background of peptides, amino acids, amino sugars, and inorganic ions. An average R.S.D. of less than 4% with recovery of greater than 86% for the three sugars was achieved. The homogeneity of the chromatographic peaks for the neutral sugars of normal human serum glycoproteins was confirmed by GLC--mass spectrometry. Significantly elevated ratios of fucose, galactose, and mannose to serum protein were observed for patients with small cell lung and ovarian carcinomas.

Carcinoma↗
PubMed1999

Tritium incorporation into functional materials by applying OT-for-OH exchange reaction.

In order to reveal (1) the behavior of the tritium-labeled hydroxyl group (i.e., OT group) and (2) the effect of temperature on the dissociation equilibrium of tritiated water, the OT-for-OH exchange reaction in a homogeneous system was observed (1) using ion-exchange resins and HTO water, and (2) using hydrogen oxides and HTO water. Consequently, the following four conclusions were obtained: (1) The OT-for-OH exchange reaction occurred between each anion-exchange resin (or each metal hydroxide) and HTO water. (2) The higher the temperature is, the smaller the activity of both anion-exchange resin and metal hydroxide will be, and the activity of cation-exchange resin is large when the temperature is high. (3) The larger the degree of crosslinking in each Biorad AG1 resin is, the lower the activity of the resin will be. (4) The exchange rate for the OT-for-OH exchange reaction is small when the electronegativity of the metal ion in the metal hydroxide is large.

Anion Exchange Resins↗
PubMed1976

A procedure for drug screening without the need to transport urines: use of ion exchange papers and hemagglutination inhibition.

A procedure was devised for screening for drug abuse in urine specimens by adsorbing the drugs onto papers loaded with ion-exchange resin. The drugs were then eluted from the papers into aqueous saline buffers, which were analyzed by hemagglutination inhibition with antisera specific for morphine, methadone, or barbiturates. The procedure combines the convenience of the ion-exchange papers with the precision and sensitivity of the immunoassay. The preliminary treatment consists of local treatment of urine specimens collected at many distant clinics with ion exchange papers that adsorb 50-65% of alkaloid drugs and 25% of barbiturates and can be shipped, after drying, in simple envelopes by regular mail to a central analytical laboratory for processing. At the central laboratory, portions of specimens are reconstituted in aqueous saline buffers, while drugs from other portions are extracted with solvents at appropriate pH. Drugs are detected in the reconstituted aqueous media by hemagglutination inhibition and spectrophotofluorimetry and confirmed in the solvent extracts by thin-layer chromatography. Recovery of labeled drugs after this treatment and urine screening data showed that the procedure is safe, convenient, and reliable in the case of opiate alkaloids, methadone, amphetamines, and phenothiazine tranquilizers but is less suitable for detection of barbiturates.

Chromatography, Ion Exchange↗
PubMed1994

Negatively charged resins stimulate bone formation in subperiosteal sites in rats. The effect of age.

The osteogenic response to subperiosteal injection of negatively charged ion exchange resins was compared in the tibiae of one-month and 16- to 22-month-old rats. The resins were administered either in the form of beads (CM Sephadex) or as particles (CM cellulose, carboxymethylcellulose), and the animals were killed at two weeks and at one month after injection. Histologically, the resins did not produce an inflammatory response. Periosteal bone formation was observed wherever resin was in contact with bone, and in the resin bed the connective tissues that invested the charged materials ossified within the first month. Marrow spaces commonly formed where periosteal growth was most rapid. The osteogenic effect was independent of resin conformation, and it was more pronounced in the younger rats.

Aging↗
PubMed1993

Studies on thio-substituted polyurethane foam (T-PUF) as a new efficient separation medium for the removal of inorganic/organic mercury from industrial effluents and solid wastes.

Novel thio-substituted flexible polyurethane foam (T-PUF) was synthesised by addition polymerisation of mercaptan with the precursors of an open-cell polyurethane foam, which can be used as a highly selective sorbent for inorganic and organic mercury from complex matrices. The percentage extraction of inorganic mercury was studied at different flow-rates, over a wide pH range at different concentrations ranging from 1 ppm, to 100 ppm. The break-through capacity and total capacity of unmodified and thio-foams were determined for inorganic and organic mercurials. The absorption efficiency of thio-foam was far superior to other sorbent media, such as activated carbon, polymeric ion-exchange resins and reagent-loaded polyurethane foams. It was observed that even at the 1000 ppm level, divalent ions like Cu, Mg, Ca, Zn do not appreciably influence the per cent extraction of inorganic mercury at the 10 ppm level. These matrix levels are the most concentrated ones which are likely to occur, both in local sewage and effluent waters. Further, the efficiency of this foam was sufficiently high at 10-100 ppm levels of Hg, even from 5-10 litres of effluent volumes using 50 g of thio-foam packed into different columns in series. Thio-foams were found to possess excellent abilities to remove and recover mercury even at low levels from industrial effluents and brine mud of chlor-alkali industry after pre-acid extraction. This makes it a highly efficient sorbent for possible application in effluent treatment. Model schemes for the removal and recovery of mercury from industrial effluents and municipal sewage (100-1000 litre) by a dynamic method are proposed and the costs incurred in a full-scale application method are indicated to show that the use of thio-foam could be commercially attractive.

Journal Article↗