Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: KEGG:D03244 (Kaolin)
 239 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have tested a platelet aggregation inhibitor in the incubation fluid of deendothelialized fragments of the rat aorta and compared it with that of "intact" fragments. Some of the properties of the aortic inhibitor, and its effects on platelet adhesion to collagen fibrils, on platelet factor-3 (PF-3) availability, and on the activated partial thromboplastin time (APTT) and thrombin time (TT) were also evaluated in comparison with similar effects exerted by PGI2. We found that the incubation fluid of deendothelialized aortic samples contained inhibitor activity comparable with that of "intact" samples. The aortic inhibitor had similar properties to PGI2. The aortic inhibitor and PGI2 slightly inhibited light transmission changes of EDTA-PRP following exposure to collagen. However, scanning electron microscopy showed no appreciable difference in platelet adhesion to collagen fibrils. PGI2 and the aortic inhibitor inhibited Kaolin-induced PF-3 availability, but did not prolong the APTT or TT.
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PMID:Generation of a PGI2-like activity by deendothelialized rat aorta. 38 19

Testing of a modified Reaction Rate Analyser 8600 in the automatic determination of coagulation time was accomplished with the assays Thrombotest Normotest and Kaolin Partial Thromboplastin Time. Variations in extinctions, from the adding of start reagent until coagulation, were recorded. The coagulation activities, found by the automatic method for the assays Thrombotest and Normotest, were compared with a manual method. Thrombotest showed a good correlation: 0.30 greater than P greater than 0.25 (paired t test). Normotest showed significantly different values by the methods: P less than 0.001 (paired t test). Kaolin Partial Thromboplastin Time (Activated Partial Thromboplastin Time with kaolin as activator) gave significantly lower vales--the difference was 3 sec--compared with a manual method, and the precision was considerably improved.
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PMID:Determination of coagulation factors (II-VII-X) and kaolin partial thromboplastin time by the LKB 8600 Reaction Rate Analyser. 61 22

The laboratory assessment of the lupus anticoagulant, a factor frequently associated with venous and arterial thrombosis, recurrent miscarriages and abortions, is not straightforward, as indicated by the variety of tests proposed and the different results obtained. On account of the marked variability and heterogeneity of lupus anticoagulant among patients, no single test or reagent will identify all patients with lupus anticoagulant, and a panel of several tests has to be used. This is time consuming and increases the workload of the laboratory. The aim of this study was to assess the minimum number of tests necessary for the satisfactory identification of the patient with lupus anticoagulant. Our study confirms that lupus anticoagulant may be present in a significant number of patients with normal routine activated partial thromboplastin time, a test which therefore cannot be used as the sole criterion for identifying patients suspected of having lupus anticoagulant. In contrast all patients who had positive results in at least one test could be detected (100% sensitivity) with two combinations of tests: (1) dilute activated partial thromboplastin time and Kaolin clotting time and (2) dilute activated partial thromboplastin time and tissue thromboplastin inhibition test. Since the latter inhibition test has been reported to give a high number of false-positive or negative results, we suggest the combination of dilute activated partial thromboplastin time and Kaolin clotting time as the standard pair of tests for the screening of suspected lupus anticoagulant patients.
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PMID:An evaluation of several laboratory tests and test combinations in the detection of lupus anticoagulant. 150 2

A 37 year-old female was admitted to our hospital because of hypermenorrhea, prolonged bleeding time, thrombocytopenia and the diagnosis of idiopathic thrombocytopenic purpura (ITP) was made. Though activated partial thromboplastin time (APTT) was markedly prolonged, her coagulation factors were within normal ranges. Activities of the circulating lupus anticoagulant (LAC) was suggested. Kaolin clotting time of the platelet poor plasma was used as a sensitive screening test using the mixture of normal and patient's plasma for the detect of LAC. As a result, LAC positive pattern was observed. The treatment with high-dose gammaglobulin brought out a transient increase of the platelet count, but the prolongation of APTT was not corrected. Both the platelet count and the prolongation of APTT were significantly improved after the treatment with betamethasone.
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PMID:[Idiopathic thrombocytopenic purpura complicated with circulating lupus anticoagulant]. 210 46

Six lyophilized plasma samples were sent to 20 "expert" laboratories for assessment of lupus anticoagulant (LA). Four samples contained pooled LA of graded potency mixed with aged normal plasma. One contained LA plus cephalin phospholipid and one contained a nonspecific venom anticoagulant. Sixteen methods were used overall with some participants using up to 8 methods. Results were scored in regard to the known potencies of LA in the samples and other known induced defects. Activated partial thromboplastin time (APTT) tests used by most participants for preliminary screening were relatively sensitive, but non-specific. Platelet or phospholipid neutralization procedures (PNP) appeared to be sensitive and specific but showed a non-linear response to increased LA content. Kaolin clotting time (KCT) tests showed the most sensitive response to increased LA content but the weaker LA were not scored as abnormal by most laboratories as the samples may have contained platelet fragments. Other commonly used tests such as the tissue thromboplastin inhibition (TTI) test and the dilute Russell's viper venom test (DRVVT) were carried out somewhat inconsistently. The variability in performance of tests in different laboratories indicates that standardization of methodology is urgently required. Generally it seemed that most clotting tests were "bypassed" by the addition of phospholipid to a known LA-positive sample in apparently direct proportion to their sensitivity. Sample preparation, especially prevention of contamination with activated platelets is a vital preliminary part in the assay of LA.
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PMID:Comparison of test methods for the lupus anticoagulant: international survey on lupus anticoagulants-I (ISLA-1). 212 77

A family with inherited combined deficiency of factor V and von Willebrand factor (vWF) is reported. Hematological examination of 41 year-old female proband and her younger brother revealed prolonged prothrombin time and Kaolin partial thromboplastin time. The level of both factor V activity and factor V antigen markedly decreased, below 15% of normal. The decreased levels of factor VIII activity and vWF activity are also seen. Furthermore, abnormal mobilities were observed in crossed immunoelectrophoresis. The protein C, S antigens and activities, and protein C inhibitor activity were within normal. Four sons have received the 50% levels of factor V from their parents. One of them also showed the 50% of factor VIII and vWF activities. From above results, this family is thought to be a case of inherited deficiency of factor V and vWF, which are transmitted as an autosomal trait apparently.
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PMID:[A family of congenital combined deficiency of factor V and von Willebrand factor]. 236 42

Traditionally, factor XI has been determined in the clinical laboratory by a modified activated partial thromboplastin time assay (aPTT) with factor XI-deficient plasma as the substrate. Coagulant assays, however, have high coefficients of variation. We previously developed a chromogenic assay for factor XI that required equipment not normally found in a clinical laboratory. We now present a modification of that assay, which is performed in 96-well microplates and can be done in any clinical laboratory or physician's office. Plasma is subjected to a brief acidification to inactivate most of the plasma protease inhibitors. Soybean trypsin inhibitor is included to stabilize the factor XIa that is generated. Kaolin is used as the contact activating surface, and the chromogenic substrate, S-2366, is used to measure the factor XIa that is formed. Results of the assay, performed in three groups of subjects, correlate well with results of the coagulant assay as performed in our laboratory and clearly differentiate between total factor XI deficiency and the deficiency of any of the other contact proteins. Unlike coagulation assays, the chromogenic assay is not influenced by the presence of heparin. Furthermore, it is not affected by lupus anticoagulants, which are antibodies directed against acidic phospholipids. Two plasma samples from patients with acquired factor XI inhibitors showed dissociation between coagulant and amidolytic activity, suggesting that the antibodies were not primarily directed toward the active site of factor XIa, which is responsible for its amidolytic activity. In contrast, patients with severe congenital deficiency of factor XI showed no activity by either assay.
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PMID:A simple and accurate microplate assay for the determination of factor XI in plasma. 337 14

The neotropical primate Callithrix jacchus infected with Junin virus presented an acute disease with hematological and neurological manifestations and died 17 to 24 days after infection. This picture is similar to that of human Argentine hemorrhagic fever (AHF). Blood coagulation and complement studies were performed in ten C jacchus animals inoculated with 10(3) TCID50 of Junin virus, the prototype pathogenic XJ strain. Four monkeys were used as normal controls. Infected monkeys and normal controls were bled to death on days 7, 14, 17, and 21. A progressive decrease in the number of platelets was found after day 7 of infection. On day 21, the last monkey had a value of 24,000/microliters. The levels of blood clotting factors did not change until day 17, when a shortened partial thromboplastin time activated with Kaolin (PTTK) (36 sec) and increased factors VIII (192.2%) and VII-X (266.6%) were found. On day 21, the PTTK was prolonged (50.7 sec) and factors II, V, and VIII, were decreased. Thrombin time was found prolonged from day 14 onward. Fibrinogen and fibrin degradation products (FDPs) were increased on days 17 (754 mg/dl and 9.2 microliters/ml) and 21 (457 mg/dl and 29.4 micrograms/ml). No changes in the levels of alpha 2 macroglobulin were observed. Complement hemolytic levels were found to be low on day 7 (58.3 UCH50, increased on day 14 (165.1), and within normal range at the end of infection (107.2). C3 levels showed a similar pattern. The bone marrow was active and hypercellular, and the number and morphology of megakaryocytes were normal in all but one of infected animals. The results of blood clotting suggest a limited activation. The complement system presented a profile of activation followed by a rebound phenomenon. The activation of complement appeared ten days before the alteration of the clotting system was evident.
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PMID:Alteration of blood coagulation and complement system in neotropical primates infected with Junin virus. 619 6

The detection of lupus anticoagulant is important in laboratory evaluation of patients with thrombotic tendencies. The aim of this workshop was to assess the effectiveness of Australian laboratories in detecting these antibodies and assess the tests used. Fourteen laboratories took part in the exercise, held as a Workshop of the National Meeting of Australian Medical Laboratory Scientists in 1990. Seven unknown plasmas were distributed for testing prior to the meeting. While 100% correctly identified 3 strong inhibitors and a moderate strength inhibitor, the detection rate for specific individual tests varied from 38-100%. The detection rate for 2 weak inhibitors varied from 0-50%. Of the most commonly performed tests the least sensitive was the dilute Russell's viper venom time and the most sensitive was the tissue thromboplastin inhibition test, however, the degree of sensitivity seemed dependent on the source of thromboplastin. In some laboratories the Kaolin clotting time, with variations, was more sensitive. All participants correctly identified a factor VIII inhibitor as not of the lupus type. The false positive detection rate was 0%. All but one of the participating laboratories used 2 or more phospholipid dependent tests for the analysis of lupus anticoagulant (LA) which is in keeping with current international guidelines.
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PMID:Detection of lupus anticoagulant--an Australian perspective. 816 99

We describe the design of a quantitative test for lupus anticoagulants (LA), based on the Activated Partial Thromboplastin Time (APTT) and the Russell Viper Venom Time (RVVT). In this assay system, test plasmas mixed 1:1 with a pooled normal plasma (NP) are tested at a low as well as a high cephalin concentration, using an ACL 3000 automated clot timer. The ratio of these two clotting times, divided by the corresponding ratio for the NP, was defined as the Lupus Ratio (LR) and calculated by means of a computer program. The frequency distribution of the LR in a reference population of 150 healthy individuals was determined, and the 97.5 percentile was defined as the upper reference limit and allocated the value one Lupus Anticoagulant Unit (LA-U). Using dilutions of one strong LA positive plasma, standard curves for LA-U determination were constructed for the APTT as well as the RVVT based test, and fitted with a log-logit computer model. The sensitivity of the tests was comparable to that of the Kaolin Clotting Time (KCT). Plasma samples from warfarin treated patients were uniformly negative, while most heparin-containing plasmas were positive in both tests. Plasmas deficient in Factors V, VIII and IX were negative, whereas one Factor VIII-inhibitor containing plasma was positive in the APTT and negative in the RVVT. The present work shows that it is possible to adapt the APPT as well as the RVVT for LA quantification. With an automated clot timer and computer based calculation of results, the assays are simple and reproducible and have a high sensitivity and specificity.
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PMID:A quantitative, semi-automated and computer-assisted test for lupus anticoagulant. 844 53


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