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PubMed1988

The effects of kaolin on the lung.

We studied the prevalence of ventilatory impairment, chest symptoms, and radiographic abnormality in a selected sample of more than 2,000 kaolin workers from east central Georgia. The presence of ventilatory impairment was related to the presence of complicated pneumoconiosis, employment in clay calcining, and cigarette smoking. In those working with calcined clay, there was an increased prevalence of abnormality of the FEV1, but not the FVC, when compared to both wet and dry processors and which could not be explained by either cigarette smoking or the presence of pneumoconiosis. The magnitude of abnormality in the calcined clay workers was, however, unlikely to lead to disabling impairment. In workers with more than 3-yr tenure, there were 90 subjects with simple pneumoconiosis and 18 with complicated pneumoconiosis, yielding an adjusted prevalence of 3.2% and 0.63%, respectively, in the sample examined. Dry processing was associated with a greater risk of developing pneumoconiosis than wet processing.

Adult↗
PubMed1983

Pneumoconiosis in Georgia kaolin workers.

Middle Georgia kaolin workers (n = 459) were surveyed for the presence of pneumoconiosis by chest radiograph and for respiratory symptoms by questionnaire. Pulmonary function was measured in all workers by spirometry. The overall prevalence of pneumoconiosis in this population was 9.2%. Multivariate analysis demonstrated that the only significant correlates with the radiographic presence of pneumoconiosis were ages greater than 55 yr and greater than 15 yr work exposure in the job category associated with greatest dust exposure. There was no correlation between the radiographic presence of pneumoconiosis and respiratory symptoms, cigarette smoking, or history of tuberculosis. Except in cases of complicated pneumoconiosis (large opacities), spirograms of workers with radiographic evidence of pneumoconiosis were not significantly different from spirograms of workers with normal radiographs. Clinical impairment of pulmonary function does not occur except in advanced cases, and appears to be mild even in these.

Adolescent↗
PubMed1969

Studies on a complex mechanism for the activation of plasminogen by kaolin and by chloroform: the participation of Hageman factor and additional cofactors.

As demonstrated by others, fibrinolytic activity was generated in diluted, acidified normal plasma exposed to kaolin, a process requiring Hageman factor (Factor XII). Generation was impaired by adsorbing plasma with glass or similar agents under conditions which did not deplete its content of Hageman factor or plasminogen. The defect could be repaired by addition of a noneuglobulin fraction of plasma or an agent or agents eluted from diatomaceous earth which had been exposed to normal plasma. The restorative agent, tentatively called Hageman factor-cofactor, was partially purified by chromatography and had an apparent molecular weight of approximately 165,000. It could be distinguished from plasma thromboplastin antecedent (Factor XI) and plasma kallikrein, other substrates of Hageman factor, and from the streptokinase-activated pro-activator of plasminogen. Evidence is presented that an additional component may be needed for the generation of fibrinolytic activity in mixtures containing Hageman factor, HF-cofactor, and plasminogen.The long-recognized generation of plasmin activity in chloroform-treated euglobulin fractions of plasma was found to be dependent upon the presence of Hageman factor. Whether chloroform activation of plasminogen requires Hageman factor-cofactor was not determined, but glass-adsorbed plasma, containing Hageman factor and plasminogen, did not generate appreciable fibrinolytic or caseinolytic activity. These studies emphasize the complex nature of the mechanisms which lead to the generation of plasmin in human plasma.

Blood Coagulation Factors↗
PubMed2003

Magnesium sulfate therapy is of mild benefit to young rats with kaolin-induced hydrocephalus.

Hydrocephalus causes damage to periventricular white matter at least in part through chronic ischemia. Magnesium sulfate (MgSO4) has been shown to be protective in various models of neurologic injury. We hypothesized that this agent would ameliorate the effects of experimental childhood-onset hydrocephalus. Hydrocephalus was induced in 3- and 4-wk-old rats by injection of kaolin into the cisterna magna. Tests of cognitive and motor function were performed on a weekly basis. In a blinded and randomized manner, MgSO4 was administered in two separate experiments (s.c. injection 0.85, 4.1, or 8.2 mM/kg/d), supplemented by osmotic minipump infusion (0.03 mM/d) to prevent low trough levels for 2 wk, beginning 2 wk after induction of hydrocephalus. The brains were then subjected to histopathological and biochemical analyses. With the 4.1 mM/kg/d dose, serum Mg++ levels were elevated transiently from 1.3 to approximately 7 mM/L. We observed statistically significant improvement in gait performance and reduced astroglial reaction. There was also a trend to improved memory performance, but no evidence of increased myelin or synaptic protein content. The 8.2 mM/kg/d dose was associated with sedation and there was no evidence of improvement in any parameter. We conclude that MgSO4 might be mildly protective in experimental hydrocephalus.

Animals↗
PubMed2005

Physicochemical properties of cross-linked poly-gamma-glutamic acid and its flocculating activity against kaolin suspension.

Cross-linked poly-gamma-glutamic acid (C-L gamma-PGA) was prepared with gamma-PGA irradiated with gamma-ray at various kGy values. The physicochemical properties including viscosity and water absorption capacity were compared between C-L gamma-PGA and several typical flocculating agents. The viscosity of C-L gamma-PGA increased with the dose of gamma-irradiation, although the water absorption capacity of C-L gamma-PGA did not, which showed a maximum of 1005.6 ml/g at 20 kGy. Flocculating activity against kaolin suspension was not observed for any of the test compounds when used singly. However, the activity of C-L gamma-PGA markedly increased following the addition of polyaluminum chloride. The activity increased with temperature up to 80 degrees C and remained at 80 degrees C of heat pretreatment for 1 h, but did not at more than 50 degrees C of heat pretreatment for 24 h. The activity was also observed within a pH range of 4.5-10.0. Both the water absorption capacity and flocculating activity of C-L gamma-PGA decreased in parallel with increasing NaCl concentration, suggesting that the flocculating activity of C-L gamma-PGA was associated with its water absorption capacity, rather than viscosity. An investigation of the effects of various cations on the flocculating activity of C-L gamma-PGA showed that only trivalent cations had a synergistic effect. The mechanism of C-L gamma-PGA flocculating activity is discussed based on the results of preliminary experiments.

Adsorption↗
PubMed2000

Effects of a kaolin-based particle film on obliquebanded leafroller (Lepidoptera: Tortricidae).

Studies were conducted in 1997 to evaluate the effects of the kaolin-based particle film formulation M96-018 on adults, eggs, and larvae of the obliquebanded leafroller, Choristoneura rosaceana (Harris). Particle film treatments significantly reduced female longevity, mating success, and number of egg masses oviposited compared with moths on untreated apple leaves in sleeve-cage and screen-cage tests. No differences in mating success or oviposition were caused by the application rates and coverage density of M96-018 on foliage. Females avoided ovipositing on particle film-treated leaves in choice tests. Larval hatch was not affected by topical application or residual exposure to M96-018. Larval weight gain and pupal weight were significantly reduced and larval mortality increased in no-choice feeding tests with M96-018. In choice tests, larvae preferred to feed on untreated leaf surfaces. The negative effects on larval development and survivorship on M96-018-treated foliage did not differ across a fourfold difference in spray application rate. A significant reduction in the number of infested shoots was found in orchard trials when M96-018 was applied before bud break in late March compared with untreated trees. No reductions in larval densities were found compared with an untreated control following prebloom and postbloom applications.

Animals↗
PubMed2002

Repellency of a kaolin particle film, Surround, and a mineral oil, Sunspray oil, to silverleaf whitefly (Homoptera: Aleyrodidae) on melon in the laboratory.

Surround, a kaolin-based particle film formulation, and Sunspray oil, a mineral oil, were evaluated alone or in combination in choice and no-choice laboratory assays on melon leaves for repellency to adults of the silverleaf whitefly, Bemisia argentifolii Bellows & Perring. In no-choice tests, the number of adults and eggs on leaves did not significantly differ among the three treatments and the water control when materials were applied to either the tipper or lower leaf surface. Significantly fewer adults and eggs were found on treated leaves compared with water when materials were applied to both leaf surfaces. Application of Surround did not affect the oviposition pattern, with 80.2-88.5% eggs oviposited on lower surface. However, whiteflies oviposited more eggs (53.1-63.8%) on the upper compared with the lower surface when Sunspray oil or Surround + Sunspray oil was applied on the lower leaf surface and both leaf surfaces. When whiteflies were allowed to choose among leaves treated with different materials on the same leaf surface(s), significantly fewer adults and eggs were found on treated leaves compared with water-treated leaves, and more adults and eggs were found on leaves when the materials were applied to tipper versus lower or both surfaces. Leaves treated with materials on both leaf surfaces had fewer whiteflies compared with leaves treated on the upper or lower surface. When whiteflies were allowed to choose among leaves treated with materials versus water-treated leaves in a 6:3 or an 8:1 ratio, significantly fewer adults and eggs were found on leaves treated with treatment materials compared with water, regardless of which leaf surface(s) were treated. No significant synergistic or additive effect was detected in Surround + Sunspray oil compared with either material used separately.

Animals↗
PubMed1992

Automation of the Kaolin Clotting Time.

An automated Kaolin Clotting Time (KCT) has been developed to simplify screening for the Lupus Anticoagulant (LA). The assay is performed on the ACL300 Research coagulation analyser, but may be modified for other centrifugal analysers. Automation of the KCT allows up to 17 delta KCT (delta KCT) screens (Gibson J, Starling E, Date L et al. Simplified screening procedure for detecting lupus inhibitor. J Clin Pathol 1988; 44: 226-31) or 2 full Exner curves (Exner T, Rickard KA, Kronenberg H. A sensitive test demonstrating lupus anticoagulant and its behavioural patterns. Br J Haematol 1978; 40: 143-51) to be performed in one test cycle. An automated and manual delta KCT screen was performed on 17 patients with a previously diagnosed LA, 41 hospital patients having routine coagulation studies and 37 blood donors. In addition, 11 patients on full-dose heparin and 12 patients with stable warfarin anticoagulation were tested. The correlation between the automated delta KCT and the manual delta KCT was 0.958 (p less than 0.001). A full Exner curve was performed on 5 of the patients with a LA and 1 blood donor which demonstrated that the automated KCT produced results entirely comparable with the manual method. The automated KCT is a quick, inexpensive approach to screening patients for the presence of LA.

Blood Coagulation Tests↗
PubMed1984

Sequential morphological and functional changes in kaolin-induced hydrocephalus.

An experimental model of kaolin-induced hydrocephalus in the dog was studied in order to evaluate the progress of ventricular dilatation and the communications between the ventricular system and the subarachnoid space. Skull and spine radiological studies were obtained after metrizamide intraventricular injection, and the baseline ventricular pressure and cerebral pulse pressure amplitude were measured in anesthetized animals. Intracranial compliance and resistance to drainage of cerebrospinal fluid were calculated by means of bolus injection test. Light and scanning electron microscope studies were done at different developmental stages of hydrocephalus. With these experimental parameters, two successive phases were seen: an initial acute hypertensive hydrocephalus (H1) with high resistance, low compliance, severe ependymal damage, and subependymal edema; and a late chronic normotensive hydrocephalus (H2) with little resistance increase, normal compliance, epithelial regeneration, and subependymal gliosis. Both the H1 and H2 stages showed an increase in the cerebral pulse pressure amplitude.

Animals↗
PubMed1991

[Alteration of endothelin-1 receptor in the choroid plexus of rats with kaolin-induced experimental hydrocephalus].

Specific binding sites for endothelin-1 (ET-1) in the choroid plexus of rats with kaolin-induced hydrocephalus were analyzed using quantitative receptor autoradiographic technique with 125I-ET-1. Unlabeled ET-1 and its natural analog ET-3 inhibited the binding of 125I-ET-1 to the choroid plexus of control rats with similar high potencies. However, possibly related substances, such as ion channel regulators (omega-conotoxin GVIA, nitrendipine, verapamil, diltiazem, alpha-bungatmtoxin, aconitine, apamin), ouabain and atrial natriuretic peptide did not affect the binding. Scatchard analysis revealed the presence of a single class and high affinity binding sites for ET-1 in the choroid plexus. The number of 125I-ET-1 binding sites in the choroid plexus of rats with kaolininduced hydrocephalus was significantly lower, when compared with those in the age-matched control rats; maximum number of binding sites (Bmax) was 16.3 +/- 0.6 and 36.2 +/- 2.5 fmol/mg, respectively (p less than 0.01, n = 5). There was no significant difference in the binding affinities; affinity constants (Ka) was 2.6 +/- 0.3 x 10(9) M in control rats and 3.5 +/- 0.5 x 10(9) in hydrocephalic rats (n = 5). These results suggest that ET receptors may play a role in the regulation of cerebrospinal fluid production.

Animals↗
PubMed1988

Assessment of plasma leukotriene and prostaglandin levels during adjuvant arthritis and kaolin-induced paw oedema in rats.

Plasma levels of some arachidonic acid metabolites were investigated in acute and chronic models of inflammation in rats. As a model of chronic inflammation, adjuvant arthritis in rats induced by the injection of Freund's complete adjuvant, and as an acute model for inflammation, kaolin-induced paw oedama were used. Plasma leukotriene(LT) C4-like and prostaglandin(PG) E2-like activities were quantitated by bioassay in guinea-pig ileum and rat stomach fundus respectively. In the course of adjuvant arthritis, plasma levels of LTC4- and PGEi2-like activities were increased. Plasma LTC4-like activity reached a maximum within 3 weeks, while PGE2-like activity reached a maximum 10 days after adjuvant injection. In the early phase of adjuvant arthritis, levels of both LTC4- and PGE2-like activities were found to be low but both activities were increased in the late phase of inflammation.

Animals↗
PubMed1979

[Morphological changes in the central canal of the cat after kaolin injection into the cisterna magna].

40 adult cats were made hydrocephalic by intracisternal injection of 200 mg Kaolin. 34 survived between 24 hours to 4 months. In 19 cases a ventriculostomy was carried out, whereby in 13 animals a contrast filling of the central canal occurred. The contrast medium injected into the ventricles entered the external CSF-space in the lumbo-sacral junction of the filum terminale. Light- and electron-microscopic studies showed adaptive structural changes of the central canal epithelium in the early stages. In later stages massive destructions of ependyma and spinal cord parenchyma were found.

Animals↗
PubMed1966

A serological test in tuberculosis. A "blind" trial of the kaolin-agglutination test (KAT) for detection of tuberculosis antibodies.

Takahashi reported in 1962 that his kaolin-agglutination test (KAT), using the phosphatide fraction of Mycobacterium tuberculosis as antigen, was capable of detecting specific antibodies in sera from patients with pulmonary tuberculosis, and that the test could differentiate between active and inactive disease.The present study was designed to investigate the diagnostic efficiency of the KAT under conditions that prevail in Africa. Blood specimens were obtained from various categories of people, ranging from presumably healthy tuberculin-negative persons to patients with far-advanced pulmonary tuberculosis, and these specimens were submitted "blindly" for serological testing.The results showed that the KAT was less sensitive and also less specific in Kenya than it had been found in Japan by Takahashi. Some reasons for this discrepancy are discussed, but no final conclusion is reached.

Adolescent↗
PubMed1977

[The kaolin-activated recalcification test in the screening of coagulation disorders and in the control of anticoagulant therapy].

The AA. have standardized a method for determining the kaolin activated plasma recalcification time (TRA) and have fixed its normal range between 33 and 60 seconds (average +/- 3 DS) testing 2000 normal subjects. By this method they have been able to demonstrate that TRA is more sensitive than PTT during the haemorrhagic manifestations in thrombocytopenic patients and in monitoring heparin therapy, while it shows a behaviour similar to PTT in detecting coagulation defects. It has also been found that TRA had remarkably increased its values in thrombocytopatic non thrombocytopenic patients, when PTT was normal. TRA does not seem to be useful in coumarin or indanedione therapy, since its values are constantly but not proportionally increased only when prothromsitive than PTT during the haemorrhagic manifestations in thrombocytopenic pabin time is very prolonged. Finally TRA can advantageusly substitute the whole blood clotting time and the non activated recalcification time for its easy performance, remarkable precision and low cost.

Anticoagulants↗
PubMed1982

In vitro experiments on chloroquine and pyrimethamine absorption in the presence of antacid constituents or kaolin.

A study was made in vitro of the effect of five gastrointestinal medications on the absorption of chloroquine and pyrimethamine, the two most commonly used antimalarial agents in the Sudan. Activated dimethicone did not appreciably affect the absorption of either antimalarial drug. All other agents tested significantly decreased the absorption of both chloroquine and pyrimethamine. The decreases observed were as follows: calcium carbonate (-52.8 and -31.5%), a local remedy, gerdiga (-36.1 and -38.0%), kaolin (-46.5 and -49.9%) and magnesium trisilicate (-31.3 and -37.5%) for chloroquine and pyrimethamine respectively. The results indicate that concomitant therapy of these antimalarials with the implicated antacid and antidiarrhoeal agents will result in poor bioavailability of the antimalarials.

Animals↗
PubMed1995

Kaolin clotting time and dilute Russell's viper venom time distinguish between prothrombin-dependent and beta 2-glycoprotein I-dependent antiphospholipid antibodies.

Antiphospholipid (aPL) antibodies include anticardiolipin (aCL) and lupus anticoagulant (LA) antibodies. LA antibodies recognize the complex of lipid-bound (human) prothrombin, in this way inhibiting the phospholipid-dependent coagulation reactions, whereas aCL antibodies are directed towards beta 2-glycoprotein I (beta 2-GPI) bound to an anionic lipid surface. According to their behavior in coagulation reactions, we have divided aCL antibodies into two groups: aCL-type A, which inhibit the phospholipid-dependent coagulation reactions because they enhance the binding of beta 2-GPI to the procoagulant phospholipid surface; and aCL-type B antibodies, which are devoid of anticoagulant properties. We report the distinctive laboratory and clinical profiles of 25 patients with well-characterized, phospholipid-dependent inhibitor of coagulation. Fourteen patients had LA antibodies (aCL-type B were concomitantly present in 10 cases, while in the other four, aCL titer was normal), and the other 11 had aCL-type A antibodies. The laboratory evaluation of the two groups showed the dilute Russell viper venom time (dRVVT) to be the most abnormal coagulation test in the aCL-type A-positive group, whereas the kaolin clotting time (KCT) was the most abnormal assay in the LA-positive group. In fact, the ratios of the coagulation times of patient plasma over normal pooled plasma (mean +/- standard deviation) for LA versus aCL-type A antibodies were 1.48 +/- 0.27 versus 2.20 +/- 0.42, P = .0001, and 2.22 +/- 0.42 versus 1.50 +/- 0.42, P = .0003, for the dRVVT and KCT, respectively. No differences were observed either in the ratios of the activated partial thromboplastin times and the prothrombin times or the plasma levels of beta 2-GPI and prothrombin. Conversely, aCL titers were significantly higher in aCL-type A-positive patients (147 +/- 44 U) than in the LA-positive group (61 +/- 55 U; P = .0003). We ruled out the possibility that platelet contamination of plasma could account for the observed coagulation profiles, as the two patterns were reproduced in platelet-free plasma. In addition, we performed clotting tests in plasma in the presence of phospholipids and calcium after addition of factor IXa or factor Xa. The assay performed with factor Xa was more sensitive to the presence of aCL-type A antibodies, while the assay performed with factor IXa was preferentially sensitive to LA-containing plasmas, supporting the earlier findings with the dRVVT and KCT assays.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1998

The Effects of Flocculation on the Propagation of Ultrasound in Dilute Kaolin Slurries.

A broadband ultrasonic spectrometer has been used to measure ultrasonic attenuation and phase velocity dispersion as functions of frequency in kaolin suspensions over a range of solid volume fractions from phi = 0.01 to phi = 0.08 and over a pH range from 3 to 9. The Harker and Temple theory was used to simulate ultrasound propagation in the suspension, using measured slope viscosity, particle size, and size distribution. Simulated results for ultrasonic attenuation and phase velocity agree well with measured values. Both sets of results agree well and show that for volume fractions above phi approximately 0.05 attenuation and velocity dispersion increase for increasing floc size, whereas for volume fractions below phi approximately 0.05 attenuation and velocity dispersion both decrease. It is proposed that the mechanism for this change in behavior around phi approximately 0.05 involves changes in floc density and floc size distribution with phi and pH. Copyright 1998 Academic Press.

Journal Article↗