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PubMed2002

[Desorption of kaolin adsorbed copper in the fish gill microenvironment].

In order to investigate the bioavailability of kaolin adsorbed copper on gills of carpio, and to explain its possible mechanism in terms of speciation, exposure experiments with constant concentration of water soluble copper and increased concentration of kaolin adsorbed copper was carried on, and the speciation analyses was developed using MINTEQA2. The results of the exposure experiment indicated that expose to kaolin adsorbed copper would increase the metal accumulation in the fish gills. The shift of the copper speciation was demonstrated via chemical equilibrium calculation. To be specific, the kaolin adsorbed copper would be partially desorbed in the fish gill microenvironment in the alkaline water environment.

Adsorption↗
PubMed1977

A comparative trial of liquid lomotil and mist kaolin in childhood diarrhoea.

Lomotil liquid in a dose of 0.3 mg/kg/day has been compared with plain mist kaolin in controlling acute diarrhoea in young children aged 6 weeks to 2 years. Lomotil was found to stop the diarrhoea faster and significantly shorten the period of hospital admission than kaolin (P less than 0.05) in children whose diarrhoea was complicated by moderate dehydration. In those with mild dehydration lomotil had no advantage over kaolin. Children with severe dehydration treated with lomotil spent on the average much shorter period in hospital than those on kaolin, but the numbers were too small to allow for useful comparison. There was no adverse effect observed in any of subjects at the dose of lomotil used.

Acute Disease↗
PubMed1980

The relative amidolytic activity of Hageman factor (factor XII) and its fragments. The effect of high-molecular-weight kininogen and kaolin.

The effect of HMW kininogen upon the amidolytic properties of two species of activated HF (factor XII), designated HFea and HFf, was studied by using the synthetic substrate S2238. HFea is an agent present in the fluid phase after mixture of HF and Sephadex gels to which ellagic acid has been adsorbed, whereas HFf is the carboxy-terminal fragment separated from HF by limited proteolysis. The specific amidolytic activity of HFea was significantly greater than that of HFf. HMW kininogen enhanced amidolysis by both HFea and HFf. In contrast, kaolin inhibited amidolysis by these enzymes, an effect counteracted by pretreatment of kaolin with HMW kininogen. The mechanisms responsible for these effects of HMW kininogen are uncertain. Its enhancement of amidolysis by fluid-phase HFea ad HFf may be related in part to its capacity to counteract substrate inhibition by S2238. The countervailing effect of HMW kininogen upon the inhibitory properties of kaolin may reflect its capacity to inhibit partially the adsorption of HFea or HFf to kaolin, allowing expression of the amidolytic properties of these enzymes in the fluid phase.

Amides↗
PubMed1976

Adsorption sites of kaolin.

The electrophoretic mobility and adsorptive properties of kaolin and kaolin pretreated with anionic and cationic materials were examined over a range of pH values. Pretreatment with anionic compounds had little effect on mobility, while adsorption of cationic species markedly reduced mobility. These results are explained by reference to the structure of kaolin, and the interdependence of adsorption properties and electrophoretic mobility are discussed.

Adsorption↗
PubMed1981

In vitro interaction of quinidine with kaolin and pectin.

The adsorption of quinidine onto kaolin was studied as a function of pH in aqueous solutions in which the ionic strength was adjusted to 0.1. The interaction of quinidine with pectin also was investigated in water and in phosphate buffer; the buffer pH and ionic strength were adjusted to 6.5 and 0.1, respectively. The in vitro results indicated that quinidine was adsorbed onto kaolin. At the highest concentration studied, the extent of adsorption increased from 3.64 mg of quinidine adsorbed/g of adsorbent at pH 2.4 to an average of 5.81 mg/g in the pH 5.5-7.5 range. In the presence of electrolytes, the interaction of quinidine with pectin was relatively small (3-13% bound) as compared to studies performed in water (66-90% bound). The data indicate that some quinidine may be adsorbed when this drug is administered concurrently with kaolin-pectin preparations.

Adsorption↗
PubMed1990

Energy metabolism in kaolin-induced hydrocephalic rat brain. Assessed by phosphorus (31P) magnetic resonance spectroscopy and the diversity of lactate-dehydrogenase and its isoenzyme patterns.

Energy metabolism in kaolin-induced hydrocephalic rat brain was assessed by means of 31-phosphorus magnetic resonance spectroscopy and measurement of the activity of lactate dehydrogenase (LDH) as well as its isoenzyme patterns. Decreases in beta-adenosine triphosphate and phosphocreatine were observed in hydrocephalic rat brains. While the intracellular pH was decreased at 2 to 4 weeks, it showed some recovery 6 weeks after injection of kaolin. The activity of LDH increased in the hydrocephalic state, and its isoenzyme-pattern changes were as follows: the LDH5 fraction was predominant in 1-week to 4-week rats while the LDH4 fraction was predominant in 4-week rat brains, and at 6-weeks, the LDH4 and LDH5 fractions were decreased. These data from rat brains with kaolin-induced hydrocephalus indicate that anaerobic glycolysis is the primary pathway of energy metabolism in the acute hydrocephalic state, while in the chronic state the emphasis shifts to aerobic glycolysis.

Animals↗
PubMed1995

The enzymatic removal of a surfactant coating from quartz and kaolin by P388D1 cells.

The macrophage-like cell line, P388D1, was exposed to dipalmitoyl lecithin (DPL)-coated respirable quartz and kaolin, and the disappearance of the DPL was monitored for up to 9 days. The coating was removed rapidly at first (about 50% in the first 3 days) and then more slowly over the remaining 6 days, until about 30% remained on day 9. The rate of DPL digestion was independent of the type of dust and the amount of coated dust within the cell, indicating the existence of an extracellular phospholipase activity. This extracellular phospholipase activity was partially characterized. It was sensitive to temperatures above 56 degrees C, the presence of EDTA, the action of the proteases trypsin and proteinase K, and pH, being active at pH 7 but not at pH 5. This is consistent with reports in the literature of the existence of an extralysosomal phospholipase which is active at pH 7 and dependent on the presence of divalent metal ions. There was a dust-dependent difference in the extracellular rate of DPL digestion from quartz and kaolin. The coating was removed more slowly from the kaolin than it was from quartz. The removal of the DPL coating seen in the presence of cells was presumably due to both an intracellular and an extracellular phospholipase.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1977

An inhibitor to rubella hemagglutination present in bovine albumin preparations: its removal by treatment with kaolin.

Certain commercial preparations of bovine albumin, fraction V, show inhibitory activity in the rubella hemagglutination (HA) and hemagglutination-inhibition (HI) tests. This does not appear to be due to albumin per se, but instead to a contaminant (or contaminants) with the properties of a lipoprotein. All inhibitory activity can be removed from albumin preparations by treatment with kaolin, gel filtration, or flotation ultracentrifugation. We have found that, even when there was no inhibition of HA titers, kaolin treatment of the albumins prior to their incorporation into the test diluent resulted in more clearly defined agglutination patterns. Reasons for and against including albumin in the test diluent are discussed. It is concluded that, although not essential, it is a worthwhile additive. Our data suggest, however, that each batch of albumin used for this purpose should be checked for the presence of inhibitor, and that treatment with kaolin might be considered as a routine step prior to its incorporation into the test diluent.

Hemagglutination Inhibition Tests↗
PubMed2005

Toxicity of the crude oil water-soluble fraction and kaolin-adsorbed crude oil on Daphnia magna (Crustacea: Anomopoda).

Crude oil is a complex mixture of hydrocarbons entering aquatic environments from accidental or normal marine and transportation activities. Toxicologic crude oil analysis is usually performed on the basis of the water-soluble fraction. However, this yields only a partial estimate of the damage caused by these contaminants because a substantial hydrophobic amount can be adsorbed onto suspended solids (biotic and abiotic), which directly affects filter-feeding species and permits bioaccumulation through trophic relationships. This study determined the acute toxic damage sustained after 48 hours caused by seven types of crude oil from Tabasco, Mexico on the cladoceran Daphnia magna. Comparisons were documented based on the responses of D. magna from application of the water-soluble fraction and exposure to entire crude oil samples adsorbed on kaolin clay. Oil-sorbed kaolin was more toxic than the water-soluble fraction in acute exposure. This confirms that tests of the water-soluble fraction tend to underestimate the toxic damage that can be produced in natural environments. Furthermore, chronic toxicity (21 days) was evaluated for crude oil samples adsorbed on kaolin at sublethal concentrations as established from Application Factors (AF) criteria. Results showed that in most cases, it is impossible to predict safe concentrations on the basis of LC(50) values because samples with lower acute toxicity exercised a greater influence on D. magna reproduction and survival when subjected to chronic exposure.

Adsorption↗
PubMed1994

Progression of kaolin-induced hydrocephalus and changes in performance of operant tasks by rats.

The behavior of rats with progressive hydrocephalus was examined to detect early neurological deterioration. Kaolin solution was injected into the cisterna magna of 10 of 17 anesthetized 8-week-old male rats (day 0), and saline in the other 7 rats (control group). Reaction time (RT, sec) and error ratio (ER, %) of unanesthetized rats escaping from electrical stimuli toward a nonstimulated sheet within a box were recorded daily from day 4 until autopsy after 4 weeks. Three rats in the kaolin group died in acute stage. Rats were assigned to either severe (S) (n = 4) or moderate (M) (n = 4) group according to the degree of ventricular dilatation at autopsy. The RTs prolonged and ERs increased in the kaolin group and they reached their minimum values. Values after the minimum RT value on day 12 in the M-group and 22 in the S-group during the chronic stage were compared with those in the controls, which decreased throughout the experiments (P < 0.03). In all animals in the S-group RT was prolonged each day with a linear regression (P < 0.005), although ER was decreased (0.69 > P > 0.23). In 3 rats and in another rat in the M-group RT was prolonged (P < 0.04 and P = 0.19) and ER was decreased in 3 rats (two: P = 0.41; one: P = 0.01) and increased in one (P = 0.55). In conclusion, deteriorated motor function is more important for early diagnosis in progressive hydrocephalus than behavioral symptoms.

Animals↗
PubMed2005

Electrokinetic removal of caesium from kaolin.

Soil, in the form of kaolin and a sample of natural soil from an industrial site, was artificially contaminated with caesium and subjected to electrokinetic treatment. The effect of catholyte pH control on the process was investigated using different acids to control the catholyte pH. During treatment the in situ pH distribution, the current flow, and the potential distribution were monitored. At the end of the treatment the pore fluid conductivity and the caesium concentration distribution was measured. The results of these experiments showed that for caesium contamination, catholyte pH control is essential in order to create a suitable environment throughout the soil to enable contaminant removal. It was found that the type of acid used to control the catholyte pH affected the rate of caesium removal (nitric, sulphuric, acetic and citric acids were tested). All of the acids tested were effective, but the highest caesium extraction was achieved when nitric acid was used to control the catholyte pH. The relatively high adsorption capacity of the soil for caesium was found to significantly reduce the rate of removal. After 240 h of treatment at 1 Vcm(-1) (using sulphuric acid to control the catholyte pH), less than 80% of the caesium was removed from a 30 cm long sample of kaolin. Electrokinetic treatment of the industrial soil sample was slower than for the kaolin, but a significant extraction rate for caesium was achieved.

Acids↗
PubMed2004

Methylnaltrexone prevents morphine-induced kaolin intake in the rat.

Opioids are frequently used analgesics, and emesis is a common opioid-induced adverse effect. Methylnaltrexone, a peripheral opioid antagonist, has the potential to block the undesired effects of opioids that are mediated by peripheral receptors while sparing the analgesic effect. We used a rat model of simulated emesis or pica to study if methylnaltrexone decreases morphine induced-kaolin consumption. We observed that after morphine administration, kaolin intake increased significantly compared to intake in the vehicle group, and the increase could be attenuated by ondansetron administration. Methylnaltrexone dose-dependently reduced kaolin ingestion induced by morphine. Morphine and methylnaltrexone did not significantly affect food intake and body weight in the experimental animals. Our data suggest that methylnaltrexone has therapeutic value in treating opioid-induced nausea and vomiting.

Animals↗
PubMed2002

Alterations in brain metabolism, CNS morphology and CSF dynamics in adult rats with kaolin-induced hydrocephalus.

The present study describes the biochemical changes, morphological development and the cerebrospinal fluid dynamics of the kaolin-induced hydrocephalus in the adult rat. Two, 4 and 6 weeks after microsurgical kaolin instillation into the rat cisterna magna the basal intracranial pressure and the cerebrospinal fluid outflow resistance were measured. To determine possible biochemical changes in the rat cerebrum, brain stem and cerebellum the concentrations of glutamine, glutamate, glutathione, aspartate, GABA, alanine and taurine were measured by high pressure liquid chromatography. In addition, ventriculomegaly and syringomyelia were assessed, measuring the lateral ventricles and central canals by means of an image-processing computer program. It could be shown that the acute phase of kaolin-induced hydrocephalus in the first 4 weeks is characterised by a high basal intracranial pressure, a considerably increased CSF outflow resistance and a rise in brain water content in the fourth week. The changes in the concentrations of amino acids were moderate. Glutamine was increased and taurine was decreased in the cerebrum and alanine was increased in the brain stem. The chronic phase, however, is defined by normal basal pressure, declining outflow resistance, progression of ventriculomegaly and distinct changes in the biochemical parameters such as a remarkable decrease of glutamate, glutamine and taurine in the cerebellum, a decrease of taurine and alanine plus an increase in glutamine in the cerebrum and an increase of alanine in the brain stem. Moreover, cerebral metabolism in the adult rat seems to be more resistant to the effects of hydrocephalus than metabolism in neonatal and infantile rats.

Age Factors↗
PubMed1977

Dissolution of silicic acid from dusts of kaolin, mica and talc and its relation to their hemolytic activity. -- an in vitro study.

Hemolysis induced by native kaolin dust was found to run parallel to the amount of silicic acid dissolved from it. Native mica and talc dusts were hemolytic only to a small extent and the silicic acid dissolution from these dusts was also smaller in comparison to that of native kaolin. The proportionality between hemolysis and the amount of dissolved silicic acid was not consistently observed in the case of acid, alkali and water treated kaolin, mica and talc dusts.

Animals↗
PubMed1978

Pulmonary response to kaolin, mica and talc in mice.

Following intratracheal inoculation the pulmonary fibrogenic response of kaolin, mica and talc was investigated in mice over a period of 210 days. All the three dusts incited acute inflammatory reaction at early periods but with mica dust the acute reaction persisted longer. Subsequently there was gradual increase in the fibroblastic activity in the focal areas and mica produced, in addition, many cholesterol cleft-like structures together with marked fibroblastic activity and lymphocytic infiltration. Towards the termination of experiment at 210 days the fibrosis, in general, remained restricted to grade II with kaolin and mica while talc produced thickened interalveolar septa. The transport of dust from lungs to lymph nodes occurred earlier with mica than with kaolin or talc dust accompanied with little fibrotic reaction. The significance of the findings has been discussed.

Animals↗
PubMed1997

Daily variation in an intensity of kaolin-induced writhing reaction in mice.

The daily variation in an intensity of kaolin-induced writhing reaction was examined in mice kept under conditions of light; 07:00 - 19:00 and dark; 19:00 - 07:00. The number of writhes was counted for 30 minutes after a single intraperitoneal injection of kaolin at 00:00, 02:00, 04:00, 06:00, 08:00, 10:00, 12:00, 14:00, 16:00, 18:00, 20:00 and 22:00. The number of writhes showed a daily variation with a peak at 18:00 and a trough at 06:00. The intensity of writhing reaction was significantly reduced by pretreatment with the bradykinin B1 (Des-Arg9-[Leu8]-BK) and B2 (icatibant) receptor antagonists. Significant daily variation in this parameter was still observed in the group with the B1 antagonist, but disappeared in the B2 antagonist-treated group. These results suggest that the kaolin-induced writhing reaction shows the daily variation with a peak at the end of the resting period and a trough at the end of the active period. The B2 receptor mediated stimuli appears to be involved in this phenomenon.

Analgesia↗
PubMed1999

Effects of ephedrine enantiomers on conditioned taste aversion and kaolin intake in rats.

The ephedrine (EPH) enantiomers, (-)-EPH and (+)-EPH, have different biological activity in the rat, with the (-)-EPH enantiomer exerting a greater impact on suppression of feeding, induction of locomotion, and activation of brown adipose tissue thermogenesis. Recent studies document that (-)-EPH treatment produces an alteration of extracellular dopamine in the brain, an effect that is consistent with the locomotor-stimulating and reinforcing effects of this drug. Whether the EPH enantiomers exert aversive actions in the rat is unknown. Experiment 1 examined the impact of systemically administered (+)-EPH (0, 5, 10, or 20 mg/kg) or (-)-EPH (0, 5, 10, or 20 mg/kg) on conditioned taste aversion (CTA) in adult male rats relative to the effect of 32 mg/kg lithium chloride (LiCl). No dose of either enantiomer produced CTA, whereas strong CTA was evident for LiCl. In Experiment 2, consumption of kaolin (a nonnutritive clay) over a 24-h period was used to assess drug toxicity. Rats treated with either 0, 5, 10, 20, or 40 mg/kg (+)-EPH or 0, 5, 10, 20, or 40 mg/kg (-)-EPH did not exhibit alteration of kaolin intake. In contrast, systematic increases in kaolin intake were observed in rats after systemic administration of LiCl (0, 16, 32, 64, and 96 mg/kg). These findings suggest that the enantiomers of EPH do not exert aversive effects at behaviorally relevant doses.

Analysis of Variance↗
PubMed2002

Impairment of spatial memory in kaolin-induced hydrocephalic rats is associated with changes in the hippocampal cholinergic and noradrenergic contents.

We investigated the relationship between the degree of spatial memory impairment in an 8-arm radial maze and the changes in the contents of acetylcholine (ACh) and noradrenaline (NA) in the dorsal and ventral hippocampus and the frontal cortex, along with histological changes in kaolin-induced hydrocephalic rats. Kaolin-induced hydrocephalic rats were divided into three groups (non-impaired, impaired and severely impaired) according to the degree of impairment in a radial maze. Thirty percent of the hydrocephalic rats could not solve a radial maze (severely impaired group), while the remaining hydrocephalic rats could (non-impaired rats in the standard task). Forty percent of the non-impaired rats in the standard task failed to solve the delayed-response task (impaired group), whereas the remaining rats were able to solve it (non-impaired group). A positive correlation was observed between the impairment of spatial memory and ventricular dilatation. The ACh content in the dorsal and ventral hippocampus, and the NA content in the ventral hippocampus were decreased in the severely impaired group. Moreover, the NA content in the ventral hippocampus was decreased in the impaired group. These results suggest that the impairment of spatial memory in kaolin-induced hydrocephalic rats is associated with dysfunction of the hippocampal cholinergic and noradrenergic systems.

Acetylcholine↗