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PubMed1988

Time course analyses of kinins and other mediators in plasma exudation of rat kaolin-induced pleurisy.

Pleurisy was induced in rats by an intrapleural injection of 0.5 ml of 1% kaolin. The exudation of plasma into the pleural cavity showed two peaks at 20 min and 3-5 h after the kaolin injection. The volume of the pleural fluid increased gradually up to 5 h. The effects of treatment with mepyramine, methysergide, captopril, bromelain and indomethacin suggested that the early phase (20 min) of exudation was mediated mainly by kinins, histamine and 5-HT, and that the late phase (3 h) was mediated by prostaglandins (PGs) and possibly kinins. We measured the levels of histamine, kinin and PG in the pleural exudate to verify the involvement of the mediators mentioned above. Intracellular histamine levels decreased markedly and extracellular histamine levels increased significantly 20 min after the induction of kaolin pleurisy. Only threshold levels of kinin were detected after the induction of pleurisy. Captopril treatment, however, increased kinin levels which peaked at 20 min and decreased rapidly thereafter. Levels of 6-keto-PGF1 alpha and thromboxane B2 showed a peak at 20 min, whereas levels of PGE2 increased gradually from 20 min to 5 h. These results indicate that kaolin-induced pleurisy is a kinin-related inflammation and could be used as a model for studying the in vivo interaction of the kallikrein-kinin system and PGs at inflammatory sites.

Animals↗

PubMed1991

Heterogeneity in the reactivity of various groups of IgM antibodies with kaolin.

Kaolin strongly adsorbed rheumatoid factor (RF) and mono-nucleosis antibodies, while cold agglutinins and some antimicrobial IgM antibodies were poorly adsorbed. Maximum adsorption took place at a pH of about 7. The degree of adsorption also depended on the amount of kaolin. Rheumatoid factor could be eluted from kaolin at pH 11 after adsorption at pH 7. The reported heterogeneity with regard to reactivity with kaolin is suggested to be due to hydrophobic interactions.

Adsorption↗

PubMed2006

Electrochemical oxidation of pulp and paper making wastewater assisted by transition metal modified kaolin.

The electrochemical oxidation of pulp and paper making wastewater assisted by transition metal (Co, Cu) modified kaolin in a 200 ml electrolytic batch reactor with graphite plate as electrodes was investigated. H(2)O(2), which produced on the surface of porous graphite cathode, would react with the catalysts to form strong oxidant (hydroxyl radicals) that can in turn destroy the pollutants adsorbed on the surface of kaolin. The transition metal (Co, Cu) modified kaolin was also characterized by XRD and SEM before and after the modification and the results showed that the transition metals were completely supported on kaolin and formed a porous structure with big BET surface. The mechanism was proposed on the basis of XPS analysis of the catalyst after the degradation process. Series of experiments were also done to prove the synergetic effect of the combined oxidation system and to find out the optimal operating parameters such as initial pH, current density and amount of catalyst. From the results it can be founded that when the initial pH was at 3, current density was 30 mA cm(-2); catalyst dose was 30 g dm(-3), COD (chemical oxygen demand) removal could reach up to 96.8% in 73 min.

Catalysis↗

PubMed2002

Differential action of ondansetron and dexamethasone to modify cisplatin-induced acute and delayed kaolin consumption ("pica") in rats.

The ability of cisplatin to induce acute (0-24 h) and delayed (24-48 and 48-72 h) phases of kaolin ingestion (pica) was investigated in the rat. Cisplatin 3 mg/kg, i.p., induced kaolin consumption during the 0-24- (P<0.001) and 48-72-h (P<0.05) periods that was antagonised by dexamethasone 1 mg/kg, i.p., administered every 12 h alone or in combination with ondansetron 2 mg/kg, i.p., administered every 12 h (P<0.05). As a single treatment, ondansetron 2 mg/kg, i.p., administered every 12 h potentiated cisplatin-induced kaolin consumption by 41% (P<0.05) during the 0-24-h period but had no action to modify the delayed response (P>0.05). Dexamethasone 1 mg/kg, i.p., administered every 12 h and cisplatin 3 and 6 mg/kg, i.p., but not ondansetron 2 mg/kg, i.p., administered every 12 h (P>0.05) reduced food consumption and decreased rat weight. The highest dose of cisplatin 6 mg/kg, i.p., induced acute (P<0.001) but not delayed kaolin ingestion (P>0.05). The action of cisplatin to induce acute and delayed pica is complicated and may be affected by drugs that modify appetite.

Animals↗

PubMed1997

In vitro adsorption of mebeverine hydrochloride onto kaolin and its relationship to pharmacological effects of the drug in vivo.

The in vitro uptake of mebeverine hydrochloride from an initial drug concentration of 0.25-4.25 or 0.2-3.6 g% w/v onto kaolin 5.0 g% w/v at pH 1.8 or 7.5, respectively, at 37 degrees C was represented by a double- layered adsorption isotherm. The calculated data were in accordance with a Langmuir adsorption isotherm for an initial drug concentration up to 2.1 or 2.0 g% w/v when a monolayer was formed at pH 1.8 or 7.5, respectively. The adsorption process is pH dependent, and is affected by the electrolyte concentration and valency. The amount of the drug desorbed (mg% w/v) by washing with different elution media at 37 degrees C followed the sequence 0.1 M hydrochloric acid > 0.1 M magnesium chloride > 0.1 M sodium chloride > simulated intestinal fluid. The results obtained from this study indicate that two mechanisms, ion exchange and physical adsorption, were involved in the uptake of mebeverine hydrochloride by kaolin. The presence of different concentrations of kaolin with the tablets or capsules of the drug, adversely affected the release rate. The in vivo and in vitro studies on guinea pig ileum showed that the presence of kaolin in a mixture with mebeverine hydrochloride did not affect to any significant level the inhibiting effect of the musculotropic drug on carbachol-induced contractions in the isolated guinea pig ileum. In vivo studies showed similar results for barium chloride as well.

Adsorption↗

PubMed2002

Enhancement of copper and cadmium adsorption on kaolin by the presence of humic acids.

The competitive adsorption equilibrium isotherms of Cu2+ and Cd2+ on kaolin have been measured at 298 K, in the presence and the absence of humic acids (HAs). HAs were found to enhance the metal adsorption capacity of mineral surfaces, in particular kaolin. This enhancement was also observed in the competitive adsorption of copper and cadmium on kaolin and kaolin-HA complex. This competitive adsorption shows that the presence of Cd2+ has not an important effect on Cu2+ adsorption, whereas a dramatic decrease is observed on the adsorption of Cd2+ in the presence of Cu2+. The Freundlich isotherm equation was found to provide an excellent fit to the experimental data. These results were compared with the independent adsorption of both heavy metals.

Adsorption↗

PubMed2002

Immobilization of radioactive waste by cementation with purified kaolin clay.

A study is undertaken to determine the waste immobilization performance of low-level wastes in cement-clay mixtures. Liquid low-level wastes are precipitated using chemical methods, followed by solidification in drums. Solidification is done using cementation processes. Long-term leaching rates of the radionuclides are used as indicators of immobilization performance of solidified waste forms. In addition to evaluating the effects of kaolin clay on the leaching properties of the cemented waste forms, the effect of addition of kaolin on the strength of the cemented waste form is also investigated. The long term leaching tests show that inclusion of kaolin in cement reduces the leaching rates of the radionuclides significantly. However, clay additions in excess of 15 wt.% causes a significant decrease in the hydrolytic stability of cemented waste form. It is found that the best waste isolation, without causing a loss in the mechanical strength, is obtained when the kaolin content in cement is 5%.

Aluminum Silicates↗

PubMed1999

Uranium in mining water of kaolin open pit in Zarów (Lower Silesia); methodology of determination and genetic remarks.

In this paper, a method of determination of uranium 238 and 234 in mining waters of Andrzej kaolin open pit in Zarów (Lower Silesia) is presented. The method is based on independent measurements of alpha and beta radiation intensities by means of a liquid scintillation spectrometer alpha/beta. The initial volume of water sample was 3 dm3, then it was diminished by chemical preparation to 6 cm3, and then 12 cm3 of scintillator was added. The lower limit of detection (for the measurement time of 8 h) for both 234U and 238U amounted to 0.02 Bq/dm3. For determination of the uranium content in ferruginous sediments precipitating from mining waters of the above-mentioned open pit, gamma ray spectrometry was used. The obtained results may be viewed as a contribution to studies on anomalous uranium concentration within this kaolin deposit. The elevated uranium content, in comparison with its average concentration in the Earth crust, is characteristic for parent rocks of Andrzej kaolin deposit, which are granitoids of Strzegom-Sobótka massif. In connection with it, the high uranium content can be observed not only in kaolin and weakly kaolinised granitoids from the deposit in question, but also in mining waters genetically related with them.

Kaolin↗

PubMed2000

Effects of simulated pulmonary surfactant on the cytotoxicity and DNA-damaging activity of respirable quartz and kaolin.

Respirable-sized quartz and kaolin dusts were pretreated with simulated pulmonary surfactant dispersions of dipalmitoyl phosphatidylcholine (DPPC) in saline to model the conditioning of particles depositing in alveolar regions of the lung. DPPC-treated and untreated dusts were used to challenge lavaged rat pulmonary alveolar macrophages in vitro. Cytotoxicity was determined over a 5-d period using both total and viable cell counts from a fluorescence-based viability assay. DNA damage, as an indication of genotoxicity, was determined over a 7-d period by the single-cell gel electrophoresis assay. Untreated quartz and kaolin both expressed a significant and potent cytotoxicity, which increased with concentration and time. DPPC-surfactant pretreatment delayed significant expression of this cytotoxicity until 3 to 5 d after challenge. Untreated quartz also caused DNA damage, which increased with concentration and time. DPPC-surfactant treatment of quartz delayed most DNA damage expression to 5 and 7 d. Untreated kaolin expressed weaker activity for DNA damage, significant at the highest concentration through 5 d, and at the higher concentrations on d 7. Surfactant treatment delayed most kaolin activity for DNA damage to 7 d after challenge.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed2003

Evaluation of chronopharmacodynamics of indomethacin by the kaolin-induced pain model in mice.

We previously showed that the kaolin-induced writhe reaction exhibits 24 h variation with a peak at the end of the resting period (14:00-18:00 h) in mice maintained under light from 07:00 to 19:00 h. In this study, we used this model to evaluate the administration-time-dependent (chronopharmacodynamic) effect of indomethacin. Indomethacin (0.5 mg/kg) was given orally to mice at 02:00, 08:00, 14:00, or 20:00 h, and the suppressive effect on kaolin-induced writhing was determined after each timed dosing. After dosing at 08:00 h, indomethacin remarkably reduced the number of writhes during the critical span of 14:00-18:00 h--the time when writhing reaction was greatest during the 24 h, while the suppressive effect of the medicine after dosing at the other clock times was relatively small. These data suggest the analgesic effect of indomethacin in mice with the kaolin-induced writhing is greater after dosing in the early resting period, which is similar to that reported in patients with nocturnalpain. The kaolin-induced pain mouse model seems to be useful for the chronopharmacodynamic evaluation of analgesic agents.

Animals↗

PubMed1981

The role of bovine high-molecular-weight (HMW) kininogen in contact-mediated activation of bovine factor XII: interaction of HMW kininogen with kaolin and plasma prekallikrein.

Previous studies from our laboratories (Sugo et al. (1980) Biochemistry 19, 3215-3220) have shown that bovine high-molecular-weight (HMW) kininogen remarkably accelerates the kaolin-mediated activation of Factor XII in the presence of prekallikrein, and that both fragment 1.2 and the light chain regions located in the COOH terminal half of the kininogen molecule are essential for the activation. In the present study, we demonstrate that the accelerating effect of HMW kininogen is mediated through its adsorption on the kaolin surface through the fragment 1.2 region and its complex formation with prekallikrein through the light chain region. The evidence is as follows: 1. HMW kininogen radio-labeled with 125I was adsorbed on kaolin and the adsorption was inhibited by the prior treatment of kaolin with fragment 1.2, fragment 1.2-light chain, kinin-free protein or HMW kininogen, but not with kinin- and fragment 1.2-free protein, light chain or low molecular-weight (LMW) kininogen. 2. The complex formation of HMW kininogen with prekallikrein in bovine plasma or in the purified system was examined by gel-filtration on a column of Sephacryl S-200 In bovine plasma, prekallikrein was eluted in the same fraction as HMW kininogen, showing an apparent molecular weight of 250,000, whereas purified prekallikrein was eluted in the fraction corresponding to an apparent molecular weight of 100,000. When purified prekallikrein was mixed with purified HMW kininogen in a mol ratio of 1 to 2, all prekallikrein was found to be associated with HMW kininogen. Furthermore, purified prekallikrein mixed with kininogen derivatives, such as kinin- and fragment 1.2-free protein, fragment 1.2-light chain or light chain, was eluted in the higher molecular weight fraction. HMW kininogen did not form a complex with prekallikrein. Using the same technique, it was shown that kinin- and fragment 1.2-free protein forms a complex not only with prekallikrein but also with kallikrein.

Adsorption↗

PubMed2007

Geobacter pickeringii sp. nov., Geobacter argillaceus sp. nov. and Pelosinus fermentans gen. nov., sp. nov., isolated from subsurface kaolin lenses.

The goal of this project was to isolate representative Fe(III)-reducing bacteria from kaolin clays that may influence iron mineralogy in kaolin. Two novel dissimilatory Fe(III)-reducing bacteria, strains G12(T) and G13(T), were isolated from sedimentary kaolin strata in Georgia (USA). Cells of strains G12(T) and G13(T) were motile, non-spore-forming regular rods, 1-2 mum long and 0.6 mum in diameter. Cells had one lateral flagellum. Phylogenetic analyses using the 16S rRNA gene sequence of the novel strains demonstrated their affiliation to the genus Geobacter. Strain G12(T) was most closely related to Geobacter pelophilus (94.7 %) and Geobacter chapellei (94.1 %). Strain G13(T) was most closely related to Geobacter grbiciae (95.3 %) and Geobacter metallireducens (95.1 %). Based on phylogenetic analyses and phenotypic differences between the novel isolates and other closely related species of the genus Geobacter, the isolates are proposed as representing two novel species, Geobacter argillaceus sp. nov. (type strain G12(T)=ATCC BAA-1139(T)=JCM 12999(T)) and Geobacter pickeringii sp. nov. (type strain G13(T)=ATCC BAA-1140(T)=DSM 17153(T)=JCM 13000(T)). Another isolate, strain R7(T), was derived from a primary kaolin deposit in Russia. The cells of strain R7(T) were motile, spore-forming, slightly curved rods, 0.6 x 2.0-6.0 microm in size and with up to six peritrichous flagella. Strain R7(T) was capable of reducing Fe(III) only in the presence of a fermentable substrate. 16S rRNA gene sequence analysis demonstrated that this isolate is unique, showing less than 92 % similarity to bacteria of the Sporomusa-Pectinatus-Selenomomas phyletic group, including 'Anaerospora hongkongensis' (90.2 %), Acetonema longum (90.6 %), Dendrosporobacter quercicolus (90.9 %) and Anaerosinus glycerini (91.5 %). On the basis of phylogenetic analysis and physiological tests, strain R7(T) is proposed to represent a novel genus and species, Pelosinus fermentans gen. nov., sp. nov. (type strain R7(T)=DSM 17108(T)=ATCC BAA-1133(T)), in the Sporomusa-Pectinatus-Selenomonas group.

Bacterial Typing Techniques↗

PubMed1982

Examination of the chloroquine-kaolin drug absorption interaction using the buccal partitioning model.

Recently, an in vivo model of drug interaction in the intestine, involving buccal absorption, has been suggested. The present work evaluates this experimental model system using chloroquine and kaolin. Kaolin was found to decrease chloroquine partitioning into the buccal membranes in three healthy volunteer subjects. This deminished absorption reflected the fact that chloroquine bioavailability after oral dosing has recently been shown to be decreased by kaolin. These findings support the use of buccal partitioning as a screening device for drug interactions occurring by adsorption or complexation in the intestine. The present interaction most likely takes place due to adsorption of the drug on to the antidiarrhoeal agent. This is likely to decrease the effectiveness of chloroquine as an anti-rheumatic or anti-malarial drug if taken together with kaolin.

Absorption↗

PubMed2006

Inability of kaolin treatment to remove nonspecific inhibitors from equine serum for the hemagglutination inhibition test against equine H7N7 influenza virus.

The hemagglutination inhibition test is used by many diagnostic and surveillance laboratories for detection of antibodies to influenza viruses. It is well known that the hemagglutination inhibition test is affected by nonspecific inhibitors present in equine serum. Several serum treatments are in use to remove these inhibitors, including treatment with kaolin. Discrepant results were observed in the authors' laboratories when using kaolin treatment before testing equine sera for antibodies against equine influenza virus (EIV) subtype-1 (H7N7). It is demonstrated here that kaolin treatment leads to false positive results when testing for antibodies against EIV subtype-1, as compared to other standard serum treatments (trypsin-periodate, receptor-destroying enzyme). Against EIV subtype-2 (H3N8), however, false positive results were not evident. Trypsinperiodate and receptor-destroying enzyme (RDE) treatments appear to be superior to kaolin for removal of nonspecific inhibitors from equine serum and should be used for serological diagnosis and surveillance of equine influenza virus.

Animals↗

PubMed1990

Demonstration of kinin-release in the peritoneal exudate of kaolin-induced writhing in mice.

Using a bradykinin enzyme immunoassay, we measured the amount of kinin in the peritoneal washings of mice with the kaolin-induced writhing reaction. Simultaneous treatment with captopril, a kininase II inhibitor, significantly increased the kinin level at 1 min after kaolin injection. Soybean trypsin inhibitor injected simultaneously with kaolin almost completely suppressed the kinin level at 1 min with or without treatment of captopril. These results suggest that kinin is released through activation of the plasma kallikrein-kinin system by kaolin, and that kinin could be a main mediator for the writhing reaction.

Animals↗

PubMed1977

The spinal cord central canal in kaolin-induced hydrocephalus.

In order to study the cause of the great individual variations in kaolin-induced hydrocephalus, the lower brain stem and upper spinal cord were examined histologically in a series of young rabbits that had received injections of kaolin into the cisterna magna. Animals with complete occlusion of the outlets from the fourth ventricle into the subarachnoid space showed only a moderate ventricular dilatation, while cases with marked hydrocephalus also plugs of kaolin in the caudal part of the fourth ventricle. The intraventricular kaolin was adherent to the roof of the fourth ventricle by strands of connective tissue and it is suggested that the plugs served as valves that initially occluded the opening of the central canal and were then lifted away as the ventricle dilated and the roof moved posteriorly. The animals with marked hydrocephalus also had extensive dilatation of the central canal with cleft formation in the posterior columns. The observations support the concept that in hydrocephalus the central canal may serve as an alternative resorption route for the cerebrospinal fluid through communication with the spinal subarachnoid space.

Animals↗

PubMed2006

Heavy water inhibiting the expression of transforming growth factor-beta1 and the development of kaolin-induced hydrocephalus in mice.

OBJECT: The authors investigated the effects of heavy water (D2O) on intrameningeal fibrosis and on the expression of cytokine production in mice with kaolin-induced hydrocephalus. METHODS: Mice in which kaolin was injected into the cisterna magna were divided into two groups: 1) Group H, which had free access to H2O as tap water; and 2) Group D, which had free access to 30% D2O as tap water before and after kaolin injection. A distilled water-injected group, which had free access to H2O as tap water was designated the sham-operated group. The authors examined the effects of D2O within 28 days after injection on the development of hydrocephalus and intrameningeal fibrosis, as well as on the expression levels of several inflammatory and fibrogenic cytokines: transforming growth factor-beta1 (TGFbeta1), fibroblast growth factor-2 (FGF2), platelet-derived growth factor (PDGF)-BB, and interleukin (IL)-6. The cerebral ventricles were less expanded, and intrameningeal fibrosis was milder in Group D than in Group H. The proliferation of fibroblasts was assessed by applying the bromodeoxyuridine labeling index, which was lower in Group D than in Group H. Expression of TGFbeta1 in the macrophages, choroid plexus, and meninges was inhibited in Group D but not in Group H. The serum level of total TGFbeta1 was significantly lower in Group D than in Group H on Day 14, whereas the levels of FGF2, PDGF-BB, and IL-6 did not differ significantly among the groups. CONCLUSIONS: Administration of D2O prevented the development of kaolin-induced hydrocephalus in mice and inhibited intrameningeal fibrosis and upregulation of TGFbeta1.

Animals↗

PubMed1999

Adsorption studies of ciprofloxacin: evaluation of magnesium trisilicate, kaolin and starch as alternatives for the management of ciprofloxacin poisoning.

In vitro experiments were performed to investigated the extend of adsorption of ciprofloxacin to kaolin, magnesium trislilicate and to a starch obtained from the tubers of Tacca involucrata (Tacca starch) and to explore the effect of varying pH on this adsorption. Activated charcoal, a standard adsorbent and antidote in the management of poisoning due to a variety of chemical agents was employed as a comparing standard. The results of the study indicate that kaolin and magnesium trisilicate adsorbed ciprofloxacin effectively while the adsorption of the drug on the starch was relatively low. Adsorption was dependent upon the quantity of the adsorbed used. Kaolin or magnesium trisilicate could serve as an effective antidotal alternative to activated charcoal in the management of ciprofloxacin poisoning. Except in cases of poisoning due to ciprofloxacin, the concurrent administration of the drug with kaolin or magnesium trisilicate may be contraindicated. Tacca starch, however, may not really be recommended for the management of ciprofloxacin poisoning.

Adsorption↗