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At least 19 recordsLinked to original sources

PubMed1976

Controlled flocculation of coarse suspensions by colloidally dispersed solids I: Interaction of bismuth subnitrate with bentonite.

Deflocculated suspensions of coarse powders tend to cake as the individual particles settle out and form compact, cohesive sediments. Limited flocculation results in looser sediments because the settled-out flocs incorporate large amounts of the liquid suspending medium. Controlled flocculation of bismuth subnitrate suspensions was achieved by the addition of small amounts of bentonite. The interaction of the coarse, positively charge bismuth subnitrate particles in aqueous suspension with negatively charged, colloidally dispersed bentonite was investigated by measuring electrophoretic mobility, sedimentation volume, and viscosity. Gradual addition of bentonite dispersion to bismuth subnitrate suspensions first reduced the zeta-potential of the bismuth subnitrate particles from +28 mv to zero, then inverted it, and finally caused it to level off at -20 mv for bismuth subnitrate-bentonite weight ratios below 200. Owing to the much greater specific surface area of bentonite, the surface of the bismuth subnitrate lath-shaped crystals was completely covered by 0.5% of its weight in clay platelets. Adhesion was promoted by electrovalences between surface bismuthyl ions and cation-exchange sites of the clay and by secondary valences. The charge neutralization of bismuth subnitrate by bentonite was a heterocoagulation process: the addition of small amounts of the clay flocculated the bismuth subnitrate suspensions and eliminated caking. While the zeta-potential of the bismuth subnitrate particles leveled off when their surface was saturated with bentonite platelets, sedimentation volume and viscosity continued to increase when the clay concentration was increased further while maintaining the bismuth subnitrate concentration constant. The excess, nonadsorbed bentonite formed the characteristic house-of-cards structure, incorporating the bentonite-coated bismuth subnitrate particles as cornerstones.

Bentonite↗

PubMed1992

Effects of bentonite on wool growth and nitrogen metabolism in fauna-free and faunated sheep.

Two experiments were carried out with sheep that originated from a fauna-free flock and were fed a soybean meal-corn silage diet with or without a bentonite supplement. One-half of the sheep fed each diet in each experiment were faunated with a mixed population of ruminal protozoa, whereas the other half of the sheep remained fauna-free until the end of both experiments. Wool growth and daily gain were measured in Exp. 1. (eight rams per treatment), which lasted 110 d, and the metabolic effects in the rumen and intestinal tract of protozoa and dietary bentonite supplement were tested with cannulated wethers (four wethers per treatment) in Exp. 2. The results of Exp. 1 showed decreased wool growth (P less than .05) due to the presence of protozoa in the rumen. Dietary supplementation with bentonite partly offset the decreased wool growth in sheep with protozoa, but there were no effects of dietary bentonite and no protozoa x bentonite interaction (P greater than .05). Daily gain was decreased by the dietary bentonite (P less than .05) supplement but was not affected (P greater than .05) by the ruminal presence of protozoa. In Exp. 2, protozoa increased (P less than .01) the ruminal concentrations of ammonia and decreased (P less than .05) the acetic:propionic acid molar ratio. Fractionation of N in the duodenal digesta flowing from the stomach to the small intestine showed that protozoa decreased (P less than .05) the flow of nonammonia N and bacterial N, and there was a protozoa x bentonite interaction for these effects (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗

PubMed1992

Effects of bentonite and monensin on selected elements in the stomach and liver of fauna-free and faunated sheep.

Forty-eight rams, originating from a fauna-free flock, were divided into three groups of 16 and fed a corn silage-based diet that was unsupplemented (control) or included bentonite or monensin supplements. Eight rams in each group were inoculated with a mixed population of ruminal protozoa; the other rams remained free of protozoa throughout the 110-d experiment. The rams had free access to drinking water and assigned diet. All rams were killed at the end of the experiment, and ruminal and abomasal contents and livers were removed and sampled. Protozoal numbers in ruminal fluid of faunated rams were lower for groups fed bentonite or monensin supplements than for the control group. Bentonite decreased and monensin increased ruminal pH. The ruminal solubilities of Cu, Zn, and Mg were decreased by the presence of ruminal protozoa, but those of Fe, Mn, and Ca were not affected. Bentonite supplement decreased, and monensin supplement increased, the ruminal solubilities of Cu, Zn, and Mg. Protozoa increased the abomasal solubilities of Fe, but the other elements were not affected. Liver concentrations of Cu were decreased by bentonite and increased by monensin, but protozoa decreased the liver concentrations of both Cu and Mg. Liver concentration of Zn was affected by a monensin x protozoa interaction and that of Mg by a bentonite x protozoa interaction. It was concluded that chronic Cu poisoning could be accelerated by dietary supplements of monensin in sheep without ruminal microfauna, and the dietary Cu bioavailability could be decreased by dietary supplements of bentonite in sheep with a normal population of protozoa in the rumen.

Abomasum↗

PubMed1986

Effect of sodium bicarbonate and sodium bentonite on digestion, solid and liquid flow, and ruminal fermentation characteristics of forage sorghum silage-based diets fed to steers.

Six ruminally cannulated steers, five Holsteins and one Hereford (250 to 295 kg), were fed 84% forage sorghum silage plus 16% supplement or 50% forage sorghum silage plus concentrate and supplement diets containing either no addition (controls), 1% sodium bicarbonate (NaHCO3) or 2% sodium bentonite in a 2 X 3 factorial arrangement of treatments in a 6 X 6 Latin-square experiment with 3-wk periods. Sodium bicarbonate increased dry matter (DM) intake when concentrate was included, but neither compound affected intake of the 84% silage diet. Bentonite lowered DM, neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibilities, but NDF disappearance from nylon bags was unchanged. Ruminal pH, osmolality and L(+) and D(-) lactate were not affected by treatment. Both NaHCO3 and bentonite tended to lower ruminal NH3-N concentrations. Bentonite lowered the molar proportion of isobutyrate in ruminal fluid relative to controls, but proportions of other volatile fatty acids (VFA) and total VFA concentrations were unchanged. Neither NaHCO3 nor bentonite affected ruminal liquid or solid volumes, dilution rate constants or ruminal outflow rates. Markers overestimated volumes, but correction with measured volumes did not change interpretation of treatment effects. It was concluded that control diets had sufficiently high baseline values of pH, dilution rate and acetate proportion to preclude changes induced by either compound, especially at 1 or 2% of DM intake. An effect on palatibility through neutralization of silage acids may have been responsible for the intake response to NaHCO3.

Animal Feed↗

PubMed1978

Studies on the effect of quartz, bentonite and coal dust mixtures on macrophages in vitro.

The effect of quartz, bentonite and coal dusts as well as the effect of the artificial mixture of these dusts on TTC reduction and extra-and intra-cellular lactate dehydrogenase activity in peritoneal rat macrophages was determined in vitro. The cell-membrane-damaging effect of quartz caused a significant extracellular release of lactate dehydrogenase. Bentonite caused no extracellular enzyme release, which leads us to believe that the biological effect of this dust is shown by decrease in intra-cellular lactate dehydrogenase activity. TTC reduction was inhibited equally by quartz and qentonite. In mixtures of quartz (60%)-bentonite (40%) dust the specific effect of quartz was inhibited by bentonite in vitro and also in vivo. We obtained the same results with coal-quartz-bentonite dust mixtures in vitro. Our experiments show that comparison of the biological effects of artificial dust mixtures and airborne dust samples is justified, and prove that performing various examinations simultaneously give fuller particulars on the probable biological effect of mineral dusts.

Animals↗

PubMed1990

[The effect of long term bentonite administration on mixed element metabolism in dwarf goats].

Pigmy goats were experimentally examined for the effects of subchronic oral applications of high doses of GDR-made bentonite on their mass element status (calcium, phosphorus, magnesium sodium, potassium). The argillaceous mineral caused slightly reduced incorporation of calcium in the bones. Bentonite-related reduction of alkaline phosphatase activity cannot be ruled out as a causative factor. Magnesium concentrations in blood serum and liver of bentonite-treated pigm goats were lower with significance than those recorded from controls. Phosphorus, sodium, and potassium metabolism was not substantively altered by bentonite application. A sodium substitution effect might possibly be achieved by admixture of bentonite to feed rations.

Administration, Oral↗

PubMed1990

Effects of lipids on thermophilic anaerobic digestion and reduction of lipid inhibition upon addition of bentonite.

The effect of bentonite-bound oil on thermophilic anaerobic digestion of cattle manure was investigated. In digestor experiments, addition of oil was found to be inhibitory during start-up and the inhibitory effect was less pronounced when the oil was added in the form of bentonite-bound oil compared to when the oil was added alone. After adaptation of the digestors, very rapid degradation of oil was observed and more than 80% of the oil was degraded within a few hours after daily feeding. In batch experiments, glyceride trioleate was found to be inhibitory to thermophilic anaerobic digestion when the concentrations were higher than 2.0 g/l. However, addition of bentonite (a clay mineral) at concentrations of 0.15% and 0.45% was found to partly overcome this inhibition. Addition of calcium chloride in concentration of 3 mM (0.033% w/v) showed a similar positive effect on the utilization of oil, but the effect was lower than with bentonite.

Anaerobiosis↗

PubMed1991

Bentonite as therapy for Lantana camara poisoning of cattle.

Bentonite was compared with activated charcoal as therapy for lantana poisoning in calves dosed 5 d previously with leaf material of the common pink-edged red taxon of Lantana camara. Both therapies were given by stomach tube as a single dose at 5 g/kg. Five of 6 calves in each of the groups given bentonite and activated charcoal recovered while 5 of 6 calves in the control group died. Calves given bentonite took 3 d longer on average to recover fully than those given activated charcoal but the effects of the 2 therapies on plasma total bilirubin concentrations were statistically indistinguishable. Bentonite was judged to have promise as a cheap alternative to activated charcoal for therapy of lantana poisoning of cattle.

Adsorption↗

PubMed1985

Effects of bentonite clay solids on poliovirus concentration from water by microporous filter methods.

To determine whether suspended solids interfere with enteric virus recovery from water by microporous filter methods, the effects of bentonite clay solids at a concentration of 10 nephelometric turbidity units on the recovery of poliovirus type 1 from seeded, activated carbon-treated, filtered tap water were studied. Volumes (500 ml) of virus-laden water at pH 5.5 or 7.5, with and without 50 mM MgCl2, were filtered through 47-mm-diameter, electropositive (Virosorb 1MDS) and electronegative (Filterite) filters that had been pretreated with Tween 80 to minimize direct virus adsorption to filter surfaces. Bentonite solids enhanced virus retention on both types of filters, even under conditions in which viruses were not solids associated. However, bentonite solids also interfered with elution of retained viruses when eluting with 0.3% beef extract-50 mM glycine (pH 9.5). Under some conditions, overall virus recoveries were lower from water with bentonite solids than from solids-free control water. The results of this study indicate that clay turbidity can interfere somewhat with virus recovery by current microporous filter methods.

Adsorption↗

PubMed1975

Preparation and properties of a cephalosporin acetylesterase adsorbed onto bentonite.

A cephalosporin acetylesterase produced by Bacillus subtilis was immobilized by adsorption onto bentonite. The immobilized enzyme (E(I)) and the soluble enzyme (E(S)) exhibited Michaelis-Menton kinetics with 7-aminocephalosporanic acid (7-ACA): K(m) = 2.8 x 10(-3) M and K(m) = 3.2 x 10(-3) M, respectively. Similar kinetics were observed with 7-(thiophene-2-acetamido)cephalosporanic acid (cephalothin), but the K(m) value measured with E(I) (3.7 x 10(-3) M) was less than one-half that measured with this substrate and E(S). The reduction in K(m) value was correlated with the ability of bentonite to adsorb cephalothin. The reaction products, acetate and deacetyl-7-ACA, were weak competitive inhibitors of E(S) and E(I). The K(i) values for E(I) were 5.0 x 10(-2) M for acetate and 3.6 x 10(-2) M for deacetyl-7-ACA. Similar values were measured with E(S) and these substrates. E(I) retained about 80% of its initial activity after 3 weeks of storage in solution at 25 C. However, the enzyme dissociated from the bentonite particles during the deacetylation reaction. This dissociation was minimized by cross-linking E(I) with glutaraldehyde or bis-dimethyladipimidate, or by adding Al(OH)(3) to the suspension. With the latter addition, E(I) was stabilized so that it could be reused nine times before one-half of the initial activity was lost.

Acetylesterase↗

PubMed1990

[The effect of long-term bentonite administration on the metabolism of selected trace elements (Fe, Cu, Zn, Mn) in the dwarf goat].

Experiments were conducted with dwarf goats to investigate effects of 160 days of oral application of high doses of bentonite on the trace element status (Fe, Cu, Zn, Mn). High levels of iron compounds in bentonite batches caused intensified incorporation of these elements into liver and kidney of dwarf goat. Copper and zinc incorporations were reduced but manganese incorporation was increased by oral application of bentonite.

Animals↗

PubMedDate not supplied

[The mechanism of plaque production by enteroviruses under bentonite overlay. Relationship between plaque production and the dynamics of intracellular virus reproduction and membrane potential of the host cell].

The association of plaque production under bentonite overlay with the cycle of intracellular reproduction of enteroviruses and the dynamics of the membrane potential of infected cells was studied. It was shown that by the time of termination of the intracellular enterovirus reproduction cycle (4 1/2-5 hours postinfection) bentonite particles were torn away from the cell surface. At the same time the membrane potential of the host cell began to decline progressively. The data obtained explain the character of morphology of virus plaques under bentonite overlay.

Bentonite↗

PubMed1976

[Metabolic activity of Candida lipolytica adsorbed to bentonite with hydrophobic chains].

The respiration of Candida lipolytica on n-tetradecane is decreased in the presence of bentonite. This inhibition is less pronounced by the introduction of hydrophobic chains on the bentonite. Oxygen demand of resting cells varies with the length of hydrophobic chains. In fermentor, addition of adsorbant does not stimulate growth, but assimilation of n-tetradecane is enhanced with certain concentrations of the adsorbant. On glucose, addition of hydrophobic chains on the adsorbant does not change the effects of bentonite on exogenous respiration and substrate assimilation.

Adsorption↗

PubMed1975

Studies of immunoglobulins, bentonite flocculation and IgE, IgG and IgM antibodies in serum from patients with trichinosis.

Serial serum samples were obtained from two patients from a family of four who ingested raw pork at a known time and in whom trichinosis developed. Single and occasionally two serum samples were obtained from other patients with proved trichinosis. Studies of these serum samples showed that elevations of serum immunoglobulin E (IgE) levels do occur but not in all serum samples and that even when these levels are elevated, they are not high enough to be of diagnostic value. This is also true for serum immunoglobulin M (IgM). Using a solid phase radioimmunoadsorbent test, IgE, IgG and IgM antibodies were detected in the serums. The IgE antibody activity appeared early but was not present in all samples. The IgM antibody activity appeared later than the IgE and IgG antibody activity, and there was a statistically significant correlation between IgM antibodies as determined by radioimmunoassay and the bentonite flocculation titers suggesting that the bentonite flocculation is due to IgM antibody. IgM antibodies detected by radioimmunoassay were positive in all serum samples from patients with trichinosis except for a sample obtained 3 days after the onset of symptoms. The early increase in IgG antibodies and the occurrence of these antibodies in all serum samples obtained more than 3 days after onset of symptoms suggest a potential diagnostic use if serial samples are available early in the course of the disease.

Bentonite↗

PubMed1977

[Adjustment of the ammonia level in the rumen by sorption on bentonite and dried beet pulp].

The effect was studied of bentonite and spent sugar beet pulp on the ammonia level in the rumen juice sheep fed hay, ground barley and a urea supplementation. In comparison with a control trial, the nitrogen supply to the rumen juice proved more continuous, this fact improving the conditions for the microbial protein synthesis at the time fo the strongest fermentation. The interaction of bentonite, beet pectin and ammonium ions is attributed to the ion exchange.

Adsorption↗

PubMed1989

[Ability of bentonite and natural zeolite to adsorb aflatoxin from liquid media].

The adsorption of aflatoxin (AF) B1, contained in aqueous medium or in synthetic medium left after the cultivation of Aspergillus parasiticus NRRL 2999, was studied in two samples of bentonite, two samples of natural zeolite, and three kinds of adsorption coal added to water, to saline, to the blood serum of pigs, to the stomach fluid of pigs or rumen fluid of cows at concentrations of 5 to 50 mg per litre. Unlike retinol-propionate and beta-carotene, AF was readily adsorbable in vitro. The initial concentration of 3.6 mg or 18 mg AFB1 per litre was reduced to 0.3-27% after exposure to 50 g of adsorbent; this reduction was greater when the AFB1 was tested in the cultivation medium and the maximum reduction was recorded when adsorption coals was involved. The effectiveness of zeolite was lower in media containing nitrogen compounds and in those cases when its doses were low. The average AF retention in the adsorbents, calculated after the determination of desorption by chloroform extraction, was 72% of the original content in the medium in the case of adsorption coals, 66% in bentonite, and 60% in zeolite.

Adsorption↗

PubMedDate not supplied

[The hemagglutinating properties and adsorption on erythrocytes of Coxsackie B-3 viruses and their selected bentonite variants].

The paper is devoted to the study of the Coxsackie B-3 viruses and their bentonite variants passaged on the primary and transplanted cell cultures for their hemagglutinating (HA) properties and a degree of adsorption on erythrocytes. It is shown possible to detect the HA activity of the Coxsackie B-3 viruses which are passaged on the transplanted cell cultures: the variant Abent has the hemagglutinating activity relative to human and rabbit erythrocytes. The variant Abent+ of the Coxsackie B-3 virus passaged on the cell culture Vero is established not to be absorbed on erythrocytes. The variant Abent and the initial population of the Coxsackie B-3 virus are adsorbed on the human erythrocytes by 90-99%. Coxsackie B-3 virus and its bentonite variants reproduced on the primary cell culture of human embryonic fibroblasts and possessing the hemagglutinating activity are 100-1000 times better adsorbed on human erythrocytes than the viruses passaged in the transplanted culture.

Adsorption↗

PubMed1975

Mechanism of the inhibitory effect of PAS granules on the absorption of rifampicin: adsorption of rifampicin by an excipient, bentonite.

The bioavailability (plasma concentrations, AUC and urinary excretion) of an oral solution of rifampicin was investigated in six healthy volunteers. Simultaneous administration of PAS granules produced a significant decrease in the absorption of RMP, whereas Na-PAS tablets had no effect. This indicated that the dosage form of the granules and not PAS itself was responsible for the interaction, and that the dissolution of RMP was not involved. The interaction could be reproduced by giving dummy granules that contained the same excipients but no PAS. The disintegration and dissolution of PAS granules in vitro correlated well with the disappearance of RMP from the solution. The major excipient of the granules, bentonite (a mineral closely related to kaolin), was found to adsorb rifampicin rapidly and strongly.

Adsorption↗