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The binding of bovine factor XII to kaolin.

Purified bovine factor XII was radiolabeled with iodine-125 and its binding to kaolin studied. Binding was rapid and was not readily reversible upon adding unlabeled factor XII. The optimum pH for binding was in the region of pH 5-7. The isoelectric point of factor XII was pH 5.7. High concentrations of urea or increasing the ionic strength of the medium did not inhibit binding. Polyvalent macromolecules, such as Polybrene and polylysine, were effective inhibitors of factor XII binding to kaolin. Polylysine caused the release of factor XII that had bound to the kaolin surface.

Animals↗

[Thermometry in experimental inflammation. I. Studies on the circadian rhythm of the paw temperature in healthy rats and temperature behavior in acute inflammation after injection of kaolin, carrageenin and dextran].

Plantar paw skin temperature development was examined in 26 healthy male albino rats using Heimann's infrared thermometer KT 41. This examination was carried out on two groups of 12 and 14 male rats after intraplantar injection of kaolin, carrageenin, and dextran. Normal untreated animals showed a distinct circadian course of daily temperature, with minimal temperatures in the morning and maximal ones in the evening, and a mean difference of 3.9 degrees C. Among the phlogistic substances injected, kaolin proved to induce the most powerful increase in plantar skin temperature. It was followed by carrageenin; temperature increase in kaolin edema, however, started later than that induced by carrageenin. No pathological skin temperature increase was found after the injection of dextran. Physiological circadian temperature course, however, was modified in an undulating fashion. All phlogistic substances persistently disturbed thermoregulation in the inflamed rat paw. The comparison of temperature development in our experiments with paw swelling in similar models described in the literature did not always show a correspondence. Quantification of the intensity of experimental inflammations in animals using only a single parameter is thus not always adequate; under certain circumstances it can even lead to wrong conclusions. Nevertheless, infrared thermometry proved to be a very suitable method of estimating skin temperature as a parameter of inflammation.

Animals↗

Effect of magnesium trisilicate and kaolin-pectin on the bioavailability of trimethoprim.

Variability in the bioavailability of orally administered trimethoprim due to Magnesium trisilicate and Kaolin-pectin has been investigated. The concentration of trimethoprim in blood was determined spectrofluorometrically at 0, 15 and 30 minutes and 1, 2, 4 and 6 hours. The area under the blood concentration curve of trimothoprim was significantly decreased, when the drug was given concurrently with magnesium trisilicate or kaolin-pectin. The mean decrease in maximum blood concentration of trimethoprim in magnesium trisilicate and kaolin-pectin treated groups was 49.94% and 29.42% respectively. The data suggest that a clinically significant interaction may occur due to concurrent administration of trimethoprim with these drugs.

Animals↗

[Comparison of adsorption capacity for FSH between kaolin and montmorillonite. Biological and immunological activity relation (author's transl)].

The adsorption capacity of urinary FSH has been studied comparatively with kaolin and montmorillonite, a new type of bentonite, never used before in gonadotrophin adsorption. To measure adsorption capacity, two different assay methods were used: bioassay (for biological activity of the kaolin and montmorillonite extracts) and radioimmunoassay (RIA) for the immunological activity of FSH in both extracts. From the present results a biological activity increase was observed in montmorillonite extracts, while no significant differences between immunological activity of FSH were found in either extract. These findings suggest that montmorillonite could replace kaolin in gonadotrophins extraction and purification methods.

Adsorption↗

Morphology of the bentonite and kaolin-induced rat-paw oedemas.

The bentonite and kaolin oedemas were simultaneously induced in the rat hind paws and their courses and morphological patterns were observed under the conditions of the same biological background. Gross examination has confirmed the former experience that the kaolin oedema has a more pronounced acute phase (maximum after five to seven hours) followed by subsequent spontaneous regression of the oedema, while the bentonite oedema has its acute phase less pronounced, attains its peak only on the second day, maintaining this same size over several weeks without substantial changes. The courses of the two oedemas were in correlation with the results of histological evaluation (oedematous exudation, polymorphonuclear and mononuclear infiltration and the phagocytic activity of the latter). Resorption of kaolin in the newly-developed non-specific granulation tissue was much faster than that of bentonite (after about three weeks, while bentonite was not resorbed even after six weeks). Further, pharmacological and histological examination was performed of the effects on the bentonite oedema of sodium salicylate and Prednisone during the first 24 hours. Both substances suppressed the oedema, sodium salicylate delayed both polymorphonuclear and mononuclear infiltration, Prednisone delayed only mononuclear infiltration. The presence of mononuclear population was confirmed also by means of the positive activity of non-specific esterase and the negative activity of alkaline phosphatase. The bentonite rat-paw oedema has thus been proved to be a suitable model of inflammatory reaction for testing anti-inflammatory drugs not only in short-term (acute) tests, but also in long-term ones, where it yields a uniform picture of non-specific foreign-body low-turnover granuloma.

Acute Disease↗

Effects of low doses of aprotinin on clotting times activated with celite and kaolin.

The effects of aprotinin (2 x 10(6) and 4 x 10(6) PIU Iniprol) on the activated clotting time (ACT) with both celite- and kaolin-activated tubes were investigated in 52 patients, scheduled for elective coronary artery bypass grafting. Two whole blood samples (2 ml sample volume) were tested simultaneously with Hemochron automated timing systems at different intervals before, during and after cardiopulmonary bypass. At none of the times of measurement there was a difference in ACT measured with celite or with kaolin as coagulation activator. It is concluded that when aprotinin is used in this low dose regimen, celite- and kaolin-activated tubes are equally reliable for monitoring ACT.

Aprotinin↗

Adsorption of Nonionic Surfactants on Kaolins

Adsorption of nonionic surfactant on kaolins of different origins was studied. The shape of the isotherm differs only slightly according to the origin of the kaolin, but the amount adsorbed is quite different. The relation between the morphology of the kaolin particles and the shape of the isotherm is not clear. Fluorescence studies show two different solubilization sites for adsorbed pyrene molecules. However, these two environments could not be correlated to the basal and lateral surfaces of the mineral particles.

Journal Article↗

Wettability, Oil Recovery, and Interfacial Tension with an SDBS-Dodecane-Kaolin System.

The wettability of kaolin with SDBS (sodium dodecyl benzene sulfonate) aqueous solutions was measured by the Washburn equation expressed as contact angles. The contact angle changes for SDBS aqueous solutions on kaolin surface was studied. The interfacial tension between the SDBS solutions and n-dodecane was measured using both drop volume and spinning drop methods. Then the oil recovery of n-dodecane on the kaolin surface was tested. It was found that the minimum contact angle (the most hydrophilic condition) and the maximum oil recovery occurred near the critical micelle concentration (CMC) of SDBS while the interfacial tension between the SDBS solution and n-dodecane was far from ultra-low. Copyright 1999 Academic Press.

Journal Article↗

Kinetics of Adsorption of Diethylene-triaminomethylated Polyacrylamide on Dispersed Kaolin Accompanied by Flocculation.

The kinetics of the adsorption of diethylene-triaminomethylated polyacrylamide on kaolin dispersed in water has been investigated. An influence of the flocculation of kaolin dispersion on polymer adsorption has been found. The kinetics of particle aggregation under the influence of dissolved polymer has been studied. Polymer adsorption and particle aggregation proceed simultaneously, accompanied by a steady decrease in the amount of adsorbed polymer per unit mass of kaolin. A mathematical model of the adsorption process, consistent with the experimental data, is described. The rate constants and their ratios have been determined. Copyright 1999 Academic Press.

Journal Article↗

Influence of dispersing agents and solution conditions on the solubility of crude kaolin.

Experiments measuring the solubility of kaolin particles in terms of the concentration of aluminum and silicon ions in supernatant were carried out as a function of the pH of the slurry over a wide range of dosages of different dispersing agents varying from 0.5 to 12 mg/(g solids). The concentrations of the metal ions in supernatant were found to be strongly affected by the type and the dosage of the dispersants and pH of the solution. In this study, the mechanism of the reaction between the dispersing agents and kaolin particles was studied and the dissolution capacities of metal ions (aluminum and silicon) were identified from kaolin particles in the absence and presence of dispersing agents. The three anionic dispersing agents used were sodium polyacrylate (Na-PAA), sodium hexametaphosphate (Na-HMP), and sodium silicate (Na-silicate), based on the industrial application of these agents and their ability to produce a stable dispersion for this purpose.

Journal Article↗

Monitoring of heparin-induced anticoagulation with kaolin-activated clotting time in cardiac surgical patients treated with aprotinin.

High-dose aprotinin appears to enhance the anticoagulant effects of heparin, as documented by increases in the activated clotting times (ACTs) during cardiopulmonary bypass; hence, some authorities have advocated reducing the dose of heparin in patients treated with aprotinin. An in vitro study by our group suggested that the increase of the ACT in the presence of aprotinin and heparin may be due to the use of celite as surface activator. We compared celite and kaolin as surface activators for the measurement of the ACT in cardiac surgical patients treated with aprotinin and in patients given no aprotinin. This double-blind, randomized, placebo-controlled study included 30 patients, of whom 14 received aprotinin and 16 received a placebo. Before, during, and after cardiopulmonary bypass, the ACT was measured with two Hemochron 400 systems with 12 mg of either celite (C-ACT) or kaolin (K-ACT) used as surface activator and with one Hepcon HMS system (HR-ACT), which uses kaolin as activator. The latter also was used for measurement of the blood heparin concentration. The ACTs of blood without heparin did not differ between aprotinin and control patients. During anticoagulation with heparin and cardiopulmonary bypass, the average C-ACTs were 784 +/- 301 s (aprotinin) and 496 +/- 120 s (control) (P < .001); the K-ACTs were 502 +/- 131 s (aprotinin) and 458 +/- 101 s (control) (P > .05); the HR-ACTs were 406 +/- 87 s (aprotinin) and 423 +/- 82 s (control) (P > .05), which was consistently less than C-ACT and K-ACT.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Final report on the safety assessment of aluminum silicate, calcium silicate, magnesium aluminum silicate, magnesium silicate, magnesium trisilicate, sodium magnesium silicate, zirconium silicate, attapulgite, bentonite, Fuller's earth, hectorite, kaolin, lithium magnesium silicate, lithium magnesium sodium silicate, montmorillonite, pyrophyllite, and zeolite.

This report reviews the safety of Aluminum, Calcium, Lithium Magnesium, Lithium Magnesium Sodium, Magnesium Aluminum, Magnesium, Sodium Magnesium, and Zirconium Silicates, Magnesium Trisilicate, Attapulgite, Bentonite, Fuller's Earth, Hectorite, Kaolin, Montmorillonite, Pyrophyllite, and Zeolite as used in cosmetic formulations. The common aspect of all these claylike ingredients is that they contain silicon, oxygen, and one or more metals. Many silicates occur naturally and are mined; yet others are produced synthetically. Typical cosmetic uses of silicates include abrasive, opacifying agent, viscosity-increasing agent, anticaking agent, emulsion stabilizer, binder, and suspending agent. Clay silicates (silicates containing water in their structure) primarily function as adsorbents, opacifiers, and viscosity-increasing agents. Pyrophyllite is also used as a colorant. The International Agency for Research on Cancer has ruled Attapulgite fibers >5 microm as possibly carcinogenic to humans, but fibers <5 microm were not classified as to their carcinogenicity to humans. Likewise, Clinoptilolite, Phillipsite, Mordenite, Nonfibrous Japanese Zeolite, and synthetic Zeolites were not classified as to their carcinogenicity to humans. These ingredients are not significantly toxic in oral acute or short-term oral or parenteral toxicity studies in animals. Inhalation toxicity, however, is readily demonstrated in animals. Particle size, fibrogenicity, concentration, and mineral composition had the greatest effect on toxicity. Larger particle size and longer and wider fibers cause more adverse effects. Magnesium Aluminum Silicate was a weak primary skin irritant in rabbits and had no cumulative skin irritation in guinea pigs. No gross effects were reported in any of these studies. Sodium Magnesium Silicate had no primary skin irritation in rabbits and had no cumulative skin irritation in guinea pigs. Hectorite was nonirritating to the skin of rabbits in a Draize primary skin irritation study. Magnesium Aluminum Silicate and Sodium Magnesium Silicate caused minimal eye irritation in a Draize eye irritation test. Bentonite caused severe iritis after injection into the anterior chamber of the eyes of rabbits and when injected intralamellarly, widespread corneal infiltrates and retrocorneal membranes were recorded. In a primary eye irritation study in rabbits, Hectorite was moderately irritating without washing and practically nonirritating to the eye with a washout. Rats tolerated a single dose of Zeolite A without any adverse reaction in the eye. Calcium Silicate had no discernible effect on nidation or on maternal or fetal survival in rabbits. Magnesium Aluminum Silicate had neither a teratogenic nor adverse effects on the mouse fetus. Female rats receiving a 20% Kaolin diet exhibited maternal anemia but no significant reduction in birth weight of the pups was recorded. Type A Zeolite produced no adverse effects on the dam, embryo, or fetus in either rats or rabbits at any dose level. Clinoptilolite had no effect on female rat reproductive performance. These ingredients were not genotoxic in the Ames bacterial test system. In primary hepatocyte cultures, the addition of Attapulgite had no significant unscheduled DNA synthesis. Attapulgite did cause significant increases in unscheduled DNA synthesis in rat pleural mesothelial cells, but no significant increase in sister chromosome exchanges were seen. Zeolite particles (<10 microm) produced statistically significant increase in the percentage of aberrant metaphases in human peripheral blood lymphocytes and cells collected by peritoneal lavage from exposed mice. Topical application of Magnesium Aluminum Silicate to human skin daily for 1 week produced no adverse effects. Occupational exposure to mineral dusts has been studied extensively. Fibrosis and pneumoconiosis have been documented in workers involved in the mining and processing of Aluminum Silicate, Calcium Silicate, Zirconium Silicate, Fuller's Earth, Kaolin, Montmorillonite, Pyrophyllite, and Zeolite. The Cosmetic Ingredient Review (CIR. The Cosmetic Ingredient Review (CIR) Expert Panel concluded that the extensive pulmonary damage in humans was the result of direct occupational inhalation of the dusts and noted that lesions seen in animals were affected by particle size, fiber length, and concentration. The Panel considers that most of the formulations are not respirable and of the preparations that are respirable, the concentration of the ingredient is very low. Even so, the Panel considered that any spray containing these solids should be formulated to minimize their inhalation. With this admonition to the cosmetics industry, the CIR Expert Panel concluded that these ingredients are safe as currently used in cosmetic formulations. The Panel did note that the cosmetic ingredient, Talc, is a hydrated magnesium silicate. Because it has a unique crystalline structure that differs from ingredients addressed in this safety assessment, Talc is not included in this report.

Animals↗

[X-ray fluorescence analysis of Kaolin concentrate].

An X-ray fluorescence technique was developed for the analysis of Al2O3, SiO2 and impurities in Kaolin concentrate. Two standard series, one for dual series of Al2O3-SiO2 and the other for all of the impurities, were prepared, respectively, from spectral pure agents based on the estimates of analyte content ranges and matrix effects in Kaolin concentrate. Powderd sample after determination of loss of ignition was pressed into disc by means of a little powderd sample preparation method modyfied in this paper. All analyte contents were calculated directly from the calibration curves without any matrix correction. In contrast to fusion technique the method has no the effects of flux impurities and dilute ration on the determination of minor and micro components in Kaolin concentrate. Errors of the results are < 1% for major component Al2O3, SiO2 and total, and < 5% for most and < 10% for few of the impurities.

English Abstract↗

Evidence that von Willebrand factor is not required for the clotting of plasma in the presence of platelets and kaolin (Hardisty-Hutton test).

Antihemophilic factor (AHF) essentially free of von Willebrand factor (vWF) was used to determine whether vWF affected the coagulant activity of AHF in a kaolin-activated system using platelet-rich plasma. The AHF was prepared by sequential chromatography on solid-phase polyelectrolyte (PE E-5), and on Sepharose CL-4B in the presence of a high concentration of CaCl2. Residual traces of vWF antigen were removed by affinity chromatography with immobilized anti-vWF IgG. The essentially vWF-free AHF corrected the clotting defect of plasma from three patients with severe von Willebrand's disease (vWD) as measured by the kaolin-activated clotting time in the presence of normal or vWD platelets ( Hardisty - Hutton test). Addition of hemophilic plasma as a source of vWF did not cause additional improvement, nor did a potent antibody to vWF raised in rabbits inhibit the ability of AHF to shorten the clotting time of vWD plasma. Thus we found no evidence that vWF is necessary for AHF to function in the coagulation of recalcified kaolin-activated vWF-deficient platelet-rich plasma.

Blood Coagulation↗

Influence of kaolin-pectin suspension on steady-state plasma digoxin levels.

The effect of a kaolin-pectin antidiarrheal mixture on steady-state plasma levels of orally administered digoxin in subjects receiving chronic digoxin therapy was evaluated when the antidiarrheal and the cardiac glycoside were given concomitantly and when two doses of antidiarrheal were given, one 2 hours before and the other 2 hours after digoxin. Although simultaneous administration of both products decreased peak digoxin levels by 36 per cent, 24-hour areas under the curve were reduced by only 15 per cent, indicative of a slight decrease in digoxin bioavailability. In contrast, when their times of administration were separated by 2 hours, no evidence of a drug interaction was noted. Hence, the effect of one or two doses of kaolin-pectin suspension on steady-state plasma levels of digoxin appears inconsequential in patients on chronic digoxin therapy. Saliva levels were poorly correlated with plasma levels, presumably because of complexation in the oral cavity.

Absorption↗

Pharmacokinetic evaluation of a drug interaction between kaolin--pectin and clindamycin.

The effect of a kaolin--pectin antidiarrheal suspension on the bioavailability of orally administered clindamycin was evaluated by model-dependent pharmacokinetic techniques. Each subject's serum clindamycin concentration--time data in the absence of the kaolin--pectin suspension were fitted to a one-compartment open model with first-order absorption and lag time. The resulting disposition parameters were used to construct individual Wagner-Nelson absorption profiles, expressed as the cumulative relative fraction of clindamycin absorbed versus time following combined antidiarrheal--antibiotic therapy. For each subject, absorption persisted to varying degrees through 14 hr. On the average, the half-time for absorption was prolonged 20-fold (from about 16 min to more than 300 min). In contrast, extrapolation of the individual time courses of relative absorption to infinity revealed that the antidiarrheal had no effect on the extent of clindamycin absorption.

Adult↗

Influence of kaolin--pectin suspension on digoxin bioavailability.

The effect of a kaolin--pectin suspension on the bioavailability of orally administered digoxin was evaluated when both drugs were given concomitantly and when their time of administration was separated by 2 hr. Coadministration of the antidiarrheal with the cardiac glycoside delayed absorption of the latter and, at the same time, decreased by 62% the amount of drug absorbed. Intersubject variation in digoxin bioavailability also was increased more than twofold. When the kaolin--pectin suspension was given 2 hr before the cardiac glycoside, the digoxin absorption rate was not affected, although its relative extent of absorption was reduced by about 20%. In contrast, when the antidiarrheal was given 2 hr after digoxin, neither the rate nor the extent of absorption of the cardiac glycoside was perturbed. No change in the intersubject variability in digoxin bioavailability was noted whether the antidiarrheal was given 2 hr before or 2 hr after the cardiac glycoside.

Adult↗

Influence of various agents on adsorption capacity of kaolin for Pseudomonas aeruginosa toxin.

The in vitro adsorption of 125I-labeled Pseudomonas aeruginosa toxin (I) onto kaolin (II) at various pH values and in the presence of various agents was studied. The maximal adsorption capacity of I onto II occurred at pH values below 4.1, while minimal values were observed at pH 4.1, 7.4, and 8; average adsorption occurred at pH 5 and 6. The tested agents at specific ratios to II decreased the percent adsorption capacity of II for I to various degrees. The results are explained by reference to the structures of both kaolin and the toxin.

Adsorption↗