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PubMed2006

Surface properties of kaolin and illite suspensions in concentrated calcium hydroxide medium.

The adsorption behaviour of calcium hydroxide onto illite and kaolin clay minerals was investigated by monitoring with atomic emission spectroscopy and pH measurements the amounts of ions left in solution after exposing clay minerals to calcium hydroxide solutions of various concentrations. Both clay minerals can adsorb calcium and hydroxyl ions. Rather than just considering proton exchanges at the clay mineral surfaces, the adsorption is explained by an approach based on Lewis description of molecules. With this approach, a mechanism for calcium hydroxide adsorption not only at the edges of the clay particles but also onto the faces is proposed. In order to gain a better insight onto the active groups at the surface of the studied clay minerals, adsorption of pyridine and ammonia on illite and kaolin was followed by FTIR spectroscopy. These measurements gave the signature of edges, which are marginally involved in interactions with calcium ions.

Journal Article↗
PubMed2002

Is the kaolin or celite activated clotting time affected by tranexamic acid?

BACKGROUND: During cardiopulmonary bypass, the activated clotting time is frequently used for determination of anticoagulation, and either Celite or kaolin are used as activators. If aprotinin is administered concomitantly, the Celite activated clotting time (C-ACT) becomes significantly higher than the kaolin activated clotting time (K-ACT). Therefore, insufficient anticoagulation using C-ACT in the presence of aprotinin is a major concern. Whether the application of tranexamic acid (TA), a pharmacologic alternative to aprotinin, has similar effects has not been studied before. METHODS: An in vitro study using the blood of healthy volunteers was performed. Both C-ACT and K-ACT were measured at baseline, after adding TA, and after adding TA and heparin. In addition, 30 patients undergoing primary cardiac operations had simultaneous measurements of C-ACT and K-ACT after skin-incision, 5 minutes after the application of heparin and TA, every 30 minutes during cardiopulmonary bypass, and 10 minutes after the application of protamine. RESULTS: In vitro, C-ACT and K-ACT correlated significantly at each measurement. Tranexamic acid had no influence on the activated clotting time. In vivo, C-ACT and K-ACT did not differ significantly, but at each time C-ACT tended to be greater than K-ACT (p = 0.086). The average difference between K-ACT and C-ACT was stable before and after the application of TA (p = 0.85) but the variability of the differences significantly increased during cardiopulmonary bypass (p < 0.001). CONCLUSIONS: Application of TA does not seem to differentially affect the mean C-ACT and K-ACT. No recommendation seems warranted to prefer one activator over the other in patients receiving TA.

Aged↗
PubMedDate not supplied

Effect of silicate minerals (zeolite, bentonite, kaolin, granite) on in vitro fermentation of amorphous cellulose, meadow hay, wheat straw and barley.

The objective of the present experiment was to determine the effects of addition of silicate minerals, zeolite (Z), bentonite (B), kaolin (K), granite (G) on the rumen fermentation parameters, total gas, methane, total and individual volatile fatty acids (VFA) and hydrogen recovery in rumen fluid inoculum from sheep. Different materials (0.25 g) meadow hay (MH), wheat straw (WS), barley (BA) and amorphous cellulose (AC) were used as substrates. Silicate minerals (0.1 g) were added to the fermentation bottles containing substrates and rumen fluid inoculum and incubated for 72 h in vitro. The gas production technique simulates fermentation in the rumen was used to determine fermentation parameters. The total gas production was significantly higher compared to control for MH plus B (MHB), MH plus G (MHG), WS plus Z (WSZ), WS plus B (WSB), WS plus K (WSK), WS plus G (WSG), AC plus B (ACB), AC plus G (ACG), BA plus Z (BAZ), BA plus B (BAB), BA plus K (BAK), BA plus granite (BAG). Significant differences of the methane production were found between the controls, WSG, BAB and BAK. The total VFA concentration was increased in ACG (83.1 mM). The acetate: propionate (A:P) ratio of the control and additives ranged between 3.1 and 3.6 for MH, 2.7 and 3.5 for WS, 1.6 and 1.8 for AC and 2.3 and 2.9 for BA. It was concluded that the silicate minerals had no appreciable effect on the methane production, however, they support the microbial metabolism by influencing (bentonite, granite) and slightly influencing (zeolite, kaolin) the rumen fermentation.

Animal Feed↗
PubMed1986

Lupus anticoagulants: improved diagnosis with a kaolin clotting time using rabbit brain phospholipid in standard and high concentrations.

We utilized a kaolin-activated partial thromboplastin time (APTT) using rabbit brain phospholipid, in which the capacity of a fourfold increased "high" phospholipid concentration (PC) to normalize the abnormal "standard" PC-APTT in patients with lupus anticoagulants is assessed. This system was also used to measure factors VIIIC, IX, and XI. The tissue thromboplastin inhibition test (TTI), a prothrombin time system in which the activity of a lupus anticoagulant is unmasked by the use of dilute thromboplastin, was simultaneously evaluated. Test sensitivity was defined by results on 31 consecutive patients with standard PC-APTT inhibitors and no bleeding tendency. Specificity was based on 94 patients with various other coagulopathies, including coagulation factor inhibitors, severe congenital factor deficiencies, hepatic insufficiency, and warfarin and heparin treatment. Twenty-one patients with lupus erythematosus and standard PC-APTT results within normal limits were also tested. Sensitivity of the APTT system was superior to that of the TTI (97% v 58%); high PC normalized clotting time ratios and factor levels. Positive results were common with both assays in the group of 20 heparinized patients. The APTT system had superior specificity in remaining cases; there were no positive tests among 74 patients. The lupus erythematosus group had a significant decrease in the clotting time ratio with high PC, indicating that low-level lupus anticoagulants are quite prevalent in this group. The kaolin clotting time using rabbit brain phospholipid in standard and high concentrations is a simple, sensitive, and specific technique for diagnosis of lupus anticoagulants.

Animals↗
PubMed1965

PARTIAL THROMBOPLASTIN TIME TEST WITH KAOLIN. NORMAL RANGE AND MODIFICATIONS FOR THE DIAGNOSIS OF HAEMOPHILIA AND CHRISTMAS DISEASE.

The partial thromboplastin time test provides a convenient and sensitive screening procedure for deficiencies of thromboplastic factors, especially factors VIII and IX. The test is carried out after preincubating the plasma for 10 minutes with kaolin, and Inosithin is used as a platelet substitute. The ;normal range' of the test has been estimated in terms of the differences encountered between random normal plasmas tested in pairs, because individual patients are usually tested against single control subjects. A patient's partial thromboplastin time should be regarded as abnormal if it is more than six seconds longer than the control time. In the diagnosis of haemophilia, patients' plasmas with concentrations of factor VIII as low as about 20% might be regarded as being within the range of normal, if the selected control subject's factor VIII happened to lie near the lower end of the normal range. When mild haemophilia is suspected, discrimination may be improved by diluting both the patient's and the control plasmas 1 in 20 in haemophilic plasma. With the test modified in this way the clotting time is prolonged, though the range of differences among normal subjects is unaltered, and plasmas with factor VIII concentrations below about 30%, i.e., in undiluted plasma, would be unlikely to be regarded as normal. The partial thromboplastin time may be similarly modified as a screening test for factor IX deficiency.Some clinical examples are reported.

Aged↗
PubMed1976

Lack of platelet factor-3 activation after incubation of platelet-rich plasma with kaolin in the rat.

Stypven times, measured in rat platelet-rich plasma (P.R.P.) after incubation with kaolin, did not shorten as incubation proceeded, thus reflecting the lack of development of platelet factor-3 (PF3) availability in this test system. Repeated freezing and thawing of P.R.P. or aggregation with collegan did result in PF-3 availability. Aggregation and PF-3 availability were inhibited by the compound VK774. These findings add another aspect to the list of species differences in platelet function.

Animals↗
PubMed1986

Evidence for a role of the plasma kallikrein-kinin system in acute inflammation: reduced exudation during carrageenin- and kaolin-pleurisies in kininogen-deficient rats.

Experimental pleurisy was induced by intrapleural injection of carrageenin or kaolin in three strains of rat: Brown Norway-Katholiek (B/N-Ka), Brown Norway-Kitasato (B/N-Ki) and Sprague-Dawley (SD). B/N-Ka rats (kininogen-deficient) showed significantly less pleural fluid accumulation and exudation rate than SD rats or than B/N-Ki rats (normal). The result indicates the involvement of the plasma kallikrein-kinin system in these pleurisies and a role of high-molecular-weight kininogen is suggested.

Acute Disease↗
PubMed1997

Glucose metabolism and protective biochemical mechanisms in a rat brain affected by kaolin-induced hydrocephalus.

To clarify glucose metabolism in a hydrocephalic rat brain, substances related to glycolytic metabolism were biochemically measured. Kaolin-induced hydrocephalic rats were sacrificed and lactate dehydrogenase (LDH), LDH isozyme, lactate, adenosine triphosphate (ATP), and isocitrate dehydrogenase (ICDH) were measured in the following regions: cortex, thalamus, midbrain, hippocampus, cerebellum, and pons with medulla. During the development of hydrocephalus, lactate and LDH increased in most regions, the LDH M-subunit increased in the cortex, and ICDH decreased in most regions. However, ATP levels did not change. The increases in lactate, LDH and M-subunit suggested an anaerobic environment in the cell leading to activation of the anaerobic glycolysis. The decrease in ICDH represented a diminution of the tricarboxylic acid cycle. Through these alterations, the ATP level can be kept constant during the course of hydrocephalus, allowing the brain to create a better biochemical milieu.

Adenosine Triphosphate↗
PubMed1988

Effect of bromelain on kaolin-induced inflammation in rats.

The effects of stem bromelain on the plasma kallikrein system, bradykinin levels and plasma exudation at the inflammatory site were examined in rats with a kaolin-induced inflammation of an air pouch. Bromelain (5, 7.5 mg/kg) caused a dose-dependent decrease of bradykinin levels at the inflammatory site and a parallel decrease of the prekallikrein levels in sera. Plasma exudation was also reduced dose dependently. Bradykinin-degrading activity in sera was elevated after treatment with bromelain, although it was unchanged in the pouch fluid. These data indicate that bromelain inhibits plasma exudation through inhibiting the generation of bradykinin at the inflammatory site via depletion of the plasma kallikrein system.

Animals↗
PubMed1980

Experimental communicating syringomyelia in dogs after cisternal kaolin injection. Part 1. Morphology.

Intracisternal kaolin injection in dogs usually produces hydrocephalus and out of 16 such dogs 11 have shown enlargement of the central canal of the spinal cord which has proceeded to syringomyelia-like cavities in 7 instances. The morphology of the cavities is described, the absence of ischaemic changes in the cord noted and the occasional communication of the cavities with the spinal subarachnoid space at the level of the filum terminale confirmed. The similarities to human syringomyelia are noted together with important differences in the etiology. The dogs all had arachnoiditis, all had hydrocephalus and all had a radiologically demonstrable communication of the cavities with the 4th ventricle, findings which are unusual in human syringomyelia.

Animals↗
PubMed1980

Experimental communicating syringomyelia in dogs after cisternal kaolin injection. Part 2. Pressure studies.

Pressure measurements in cerebrospinal fluid have been made from the ventricles and the spinal subarachnoid space in dogs made hydrocephalic by intracisternal injections of kaolin. Raised intraventricular pressure has been confirmed in the confirmed in the ventricles. The spinal pressure is usually markedly different from that in the head, confirming that the arachnoiditis produced around the cistern isolates the spinal subarachnoid space from the CSF in the head. Pulsatile pressures have been investigated specifically and the interrelationship between the pulsation and baseline pressures in the development of communicating syringomyelia discussed. There are differences between these experimental animals and the human disease, particularly in the baseline pressures which are usually equal in the head and the spine of humans at rest even in cases with syringomyelia.

Animals↗
PubMed1991

The effects of sucralfate suspension and diphenhydramine syrup plus kaolin-pectin on radiotherapy-induced mucositis.

A prospective, double-blind study compared the effectiveness of sucralfate suspension with diphenhydramine syrup plus kaolin-pectin in reducing severity and pain of radiation-induced oropharyngeal mucositis. Fourteen patients who received at least 4600 cGy to the oral cavity used one of the mouth rinses four times a day, beginning at 1600 cGy. Data were collected on daily perceived pain and helpfulness of mouth rinse, weekly mucositis grade, weight change, and interruption of therapy. Analysis of data revealed no statistically significant differences between the two groups in any parameter. A retrospective review of 15 patients who had received at least 4600 cGy radiation to the oropharynx but had not used a daily mouth-coating rinse, was compared with the study group. Comparison of the two groups suggested that consistent daily oral hygiene and use of a mouth-coating agent will result in less pain and may reduce weight loss and interruption of radiation because of severe mucositis.

Adult↗
PubMed1995

The detection of lupus anticoagulant using the kaolin clotting time test: a comparative study of the different forms of analysis.

This work is a report of a comparative study between the different forms of analysis (curve, index, percentage and delta) of kaolin clotting time (KCT) for the detection of lupus anticoagulant. The reference values for all tests were defined from a study of 111 normal controls. 133 patients were studied, 106 with connective tissue disease and 27 with syphilis. LA was detected in 31 of the 133 patients studied. For KCT, the percentage and the delta showed greater sensitivity (61% and 65%, respectively) as opposed to the curve and the index (48% and 26%, respectively). We found significant statistical differences between the frequency of positivity of the index and the delta (p < 0.001) and between the index and the percentage (p < 0.005). Our findings show that if it is necessary to use KCT as a complementary test for the detection of LA, then it is more convenient to carry it out by using the percentage or the delta forms of analysis.

Adolescent↗
PubMed1982

Decline in specificity of the ELISA due to storage of serum, and its recovery by adsorption with kaolin.

Several laboratories have experienced problems with the enzyme-linked immunosorbent assay (ELISA) due to non-specific background binding of human sera, but no general solution has been introduced. In this study the ELISA was used to measure antibody to herpes simplex virus in human sera which had been stored at -20 degrees C for up to 3 years, and the specificity was assessed by comparing the absorbance achieved with the virus neutralization titer. The severity of background binding was minimal in sera which had been obtained recently, but increased with storage time and gradually eliminated the specificity of the assay. When sera were adsorbed with kaolin, background binding of all sera was markedly reduced and the specificity was restored.

Adsorption↗
PubMed1993

Serodiagnosis of tuberculosis: assessment of kaolin agglutination test.

Kaolin agglutination test (KAT), for the detection of anti-tuberculophospholipid antibodies for the serodiagnosis of tuberculosis, was performed on the sera of 137 pulmonary and 276 extra pulmonary tuberculosis patients and 140 controls. The sensitivity and specificity of KAT was 86.9% and 100%, respectively, at the titre of 1:128 and more.

Agglutination Tests↗
PubMed2004

Two-dimensional model for soil electrokinetic remediation of heavy metals. Application to a copper spiked kaolin.

A two-dimensional numerical model has been developed to simulate the electrokinetic remediation of soils contaminated with heavy metals and has been validated using laboratory experiments performed with a copper spiked kaolin. The model divides the soil into compartments in a Cartesian grid and a non-conductivity barrier encloses the considered area. Basically, it consists in two main parts clearly distinguishable. The first part describes the electromigration phenomenon in the soil, which is represented by a set of electric resistors, following the Cartesian grid and using Kirchoff's laws of electricity to calculate the voltage drop distribution in the considered area. The second part describes the chemical equilibrium process between the heavy metal and the soil, assuming local equilibrium conditions within the compartments. A good agreement was obtained between the lab scale experimental assays and the model predictions. The model has also been used to examine the effect of the electrolyte neutralization within the scope of the acid-enhanced electrokinetic method. These simulations have foreseen problems related with the system evolution, which would not arise under one-dimensional geometries and are due to the changes of the potential distribution in the two-dimensional arrangement where some kind of short circuit arises, ultimately leading to a decrease of the system efficiency.

Copper↗
PubMed2005

Improvement in electrokinetic remediation of heavy metal spiked kaolin with the polarity exchange technique.

In the electrokinetic treatment of heavy metal polluted soil, an alkaline environment is generated at the cathode side. It provokes the precipitation of metal ions as hydroxides into the soil and diminishes the capability of the electroremediation to clean the polluted site. In this work the "polarity exchange" technique is presented as a simple way to avoid the negative effect of OH(-) on metal transportation. This technique lies in the operation during short time intervals at inverted polarity, so that the generation of H+ ions from the oxidation of water neutralize in the alkaline zone where the metal is precipitated, favouring its dissolution. Once the metals are redissolved, the polarity is set to the original position to transport them to the desired direction. Kaolin clay contaminated with Mn was used to test the feasibility of the polarity exchange technique. The application of the "conventional technique" dealt with a removal of 14% of the initial Mn in 7.6d. For a similar treatment time the polarity exchange technique resulted in 72% of removed Mn. Successive polarity exchanges will yield with a complete decontamination of the soil with a moderate increment in the electric power consumption.

Electrochemistry↗
PubMed2006

Brain damage in neonatal rats following kaolin induction of hydrocephalus.

Neonatal and congenital hydrocephalus are common problems in humans. Hydrocephalus was induced in 1-day-old rats by injection of kaolin into the cisterna magna. At 7 and 21 days, magnetic resonance (MR) imaging was used to assess ventricle size, then brains were subjected to histopathological and biochemical analyses. Hydrocephalic pups did not exhibit delays in righting or negative geotaxis reflexes during the first week. At 7 days, there was variable ventricular enlargement with periventricular white matter edema, axon damage, reactive astrogliosis, and accumulation of macrophages in severe but not mild hydrocephalus. Cellular proliferation in the subependymal zone was significantly reduced. The cortical subplate neuron layer was disrupted. In rats allowed to survive to 21 days, weight was significantly lower in severely hydrocephalic rats. They also exhibited impaired memory in the Morris water maze test. Despite abnormal posture, there was minimal quantitative impairment of walking ability on a rotating cylinder. At 21 days, histological studies showed reduced corpus callosum thickness, fewer mature oligodendrocytes, damaged axons, and astroglial/microglial reaction. Reduced myelin basic protein, increased glial fibrillary acidic protein, and stable synaptophysin content were demonstrated by immunochemical methods. In conclusion, impairment in cognition and motor skills corresponds to ventricular enlargement and white matter destruction. Quantitative measures of weight, memory, ventricle size, and myelin, and glial proteins in this neonatal model of hydrocephalus will be useful tools for assessment of experimental therapeutic interventions.

Age Factors↗