Activation of Hageman Factor in Rat Anaphylaxis

1975 ◽  
Author(s):  
L. Fésüs ◽  
L. Muszbek
Keyword(s):  
Blood Clotting ◽  
Plasminogen Activators ◽  
Factor Xii ◽  
Clotting Time ◽  
Hageman Factor ◽  
Kaolin Clotting Time ◽  
Aggregation Of Platelets ◽  
Recalcification Time

At various intervals after antigen injection assays concerning haemostatic parameters were carried out in anaphylactic shock of rats pretreated with Bordetella Pertussis Vaccine. These were as follows: measurement of whole blood clotting time, recalcification time, partial thromboplastin time, kaolin clotting time in siliconised tubes, determination of the level of factor XII, measurement of plasminogen activator level, in vitro aggregation of platelets. The different clotting times shortened and the aggregation of platelets was inhibited within the first three-four minutes. The clotting times lengthened, the level of plasminogen activators increased, the level of factor XII decreased during the further minutes. These results and their comparison with that of produced by ellagic acid injection suggest that during anaphylaxis of rats the activation of Hageman factor takes place, which is followed by its partial consumption.

Effect of Temperature, Velocity Gradient and I.V. Heparin on in Vitro Blood Coagulation and Platelet Aggregation

1967 ◽  
Vol 17 (01/02) ◽  
pp. 112-119 ◽  
Author(s):  
L Dintenfass ◽  
M. C Rozenberg
Keyword(s):  
Blood Coagulation ◽  
Velocity Gradient ◽  
Elevated Temperatures ◽  
Morphological Changes ◽  
Effect Of Temperature ◽  
Clotting Time ◽  
Progressive Change ◽  
Aggregation Of Platelets ◽  
Microscopic Techniques

SummaryA study of blood coagulation was carried out by observing changes in the blood viscosity of blood coagulating in the cone-in-cone viscometer. The clots were investigated by microscopic techniques.Immediately after blood is obtained by venepuncture, viscosity of blood remains constant for a certain “latent” period. The duration of this period depends not only on the intrinsic properties of the blood sample, but also on temperature and rate of shear used during blood storage. An increase of temperature decreases the clotting time ; also, an increase in the rate of shear decreases the clotting time.It is confirmed that morphological changes take place in blood coagula as a function of the velocity gradient at which such coagulation takes place. There is a progressive change from the red clot to white thrombus as the rates of shear increase. Aggregation of platelets increases as the rate of shear increases.This pattern is maintained with changes of temperature, although aggregation of platelets appears to be increased at elevated temperatures.Intravenously added heparin affects the clotting time and the aggregation of platelets in in vitro coagulation.

A Comparison of Anticoagulation Activity of a Potent Heparin Preparation in Different Test

1979 ◽  
Author(s):  
A.S. Bhargava ◽  
J. Heinick ◽  
Chr. Schöbel ◽  
P. Günzel
Keyword(s):  
Blood Clotting ◽  
Anticoagulant Activity ◽  
Factor Xa ◽  
Thrombin Time ◽  
Beagle Dogs ◽  
Clotting Time ◽  
Relative Potencies ◽  
Heparin Preparation

The anticoagulant effect of a new potent heparin preparation was compared with a commercially available heparin in vivo after intravenous application in beagle dogs. The anticoagulant activity was determined using thrombin time, activated partial thromboplastin time and whole blood clotting time after 5, 10 and 30 minutes of application. The relative potency of the new heparin preparation (Scherinq) was found to be 1.62 to 2.52 times higher than heparin used for comparison (150 USP units/mg, Dio-synth). The anticoagulant properties of both preparations were also studied in vitro using dog and human plasma. The relative potencies in vitro correlated well with those obtained in vivo. Further characterization with amidolytic method using chromogenic substrate for factor Xa and thrombin (S-2222 and S-2238 from KABI, Stockholm) showed that heparin (Schering) contains 243 to 378 USP units/raq depending upon the test systems used to assay the anticoagulation activity and in addition, proves the validity of the amidolytic method.

scholarly journals Factor XII-Deficient Chicken Plasma as a Useful Target for Screening of Pro- and Anticoagulant Animal Venom Toxins

Toxins ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 79
Author(s):  
Benedito C. Prezoto ◽  
Nancy Oguiura
Keyword(s):  
High Sensitivity ◽  
Factor Xii ◽  
Dependent Manner ◽  
Clotting Time ◽  
Natural Factor ◽  
Rotational Thromboelastometry ◽  
Factor Xii Deficiency ◽  
Dose Dependent ◽  
Recalcification Time ◽  
Coagulation Pathway

The sensitivity of vertebrate citrated plasma to pro- and anticoagulant venom or toxins occurs on a microscale level (micrograms). Although it improves responses to agonists, recalcification triggers a relatively fast thrombin formation process in mammalian plasma. As it has a natural factor XII deficiency, the recalcification time (RT) of chicken plasma (CP) is comparatively long [≥ 1800 seconds (s)]. Our objective was to compare the ability of bee venom phospholipase A2 (bvPLA2) to neutralize clot formation induced by an activator of coagulation (the aPTT clot) in recalcified human and chicken plasmas, through rotational thromboelastometry. The strategy used in this study was to find doses of bvPLA2 that were sufficient enough to prolong the clotting time (CT) of these activated plasmas to values within their normal RT range. The CT of CP was prolonged in a dose-dependent manner by bvPLA2, with 17 ± 2.8 ng (n = 6) being sufficient to displace the CT values of the activated samples to ≥ 1800 s. Only amounts up to 380 ± 41 ng (n = 6) of bvPLA2 induced the same effect in activated human plasma samples. In conclusion, the high sensitivity of CP to agonists and rotational thromboelastometry could be useful. For example, during screening procedures for assaying the effects of toxins in several stages of the coagulation pathway, such as clot initiation, formation, stability, strength, or dissolution.

Anticlotting activity of phosvitin on chicken blood in vitro

1962 ◽  
Vol 203 (6) ◽  
pp. 1170-1172 ◽  
Author(s):  
Koji Sato ◽  
Kazutaka Homma ◽  
Jiro Gotoh
Keyword(s):  
Whole Blood ◽  
Blood Clotting ◽  
Egg Yolk ◽  
Clotting Time ◽  
Chicken Blood ◽  
Blood Clotting Time

Phosvitin, a phosphoprotein isolated from the vitellin of egg yolk, prolonged the whole blood clotting time in the chicken blood in vitro. The degree of phosvitin's inhibition of coagulation was inversely related to the level of egg-yolk-like material in plasma induced by estrogen.

In vivo activation and functions of the protease factor XII

2014 ◽  
Vol 112 (11) ◽  
pp. 868-875 ◽  
Author(s):  
Jenny Björkqvist ◽  
Katrin Nickel ◽  
Evi Stavrou ◽  
Thomas Renné
Keyword(s):  
Cardiovascular System ◽  
Inflammatory Diseases ◽  
Contact System ◽  
Factor Xii ◽  
Hageman Factor ◽  
Current Review ◽  
Exciting Opportunity ◽  
System Factor

SummaryCombinations of proinflammatory and procoagulant reactions are the unifying principle for a variety of disorders affecting the cardiovascular system. Factor XII (FXII, Hageman factor) is a plasma protease that initiates the contact system. The biochemistry of the contact system in vitro is well understood; however, its in vivo functions are just beginning to emerge. The current review concentrates on activators and functions of the FXII-driven contact system in vivo. Elucidating its physiologic activities offers the exciting opportunity to develop strategies for the safe interference with both thrombotic and inflammatory diseases.

A Simple Procedure for Accurate Quantitation of Factor VIII Inhibitors

1970 ◽  
Vol 23 (01) ◽  
pp. 019-025 ◽  
Author(s):  
Daphne Tse ◽  
L Fekete ◽  
E Shanbrom
Keyword(s):  
Factor Viii ◽  
Therapeutic Response ◽  
Simple Procedure ◽  
Clotting Factor ◽  
Clotting Time ◽  
Precise Calculation ◽  
Control Plasma

SummaryA simple assay for quantitative determination of factor VIII (AHF) inhibitors has been developed. The presence of AHF inhibitor is confirmed by determining clotting time in serial dilutions of patient’s plasma. The amount of inhibitor is then quantitat-ed by adding known units of human AHF concentrate (1 to 100 units/ml) to plasma until neutralization occurs. The neutralization point is defined as that level of AHF concentrate which clots the patient’s plasma in the same time as the control plasma (inhibitor-free) would clot in the presence of 1 unit of AHF concentrate. (This point, minus the initial 1 unit/ml, gives the titer of inhibitor present (units/ml). The dosage of AHF concentrate required to overcome the inhibitor and raise the free circulating AHF to the desired theoretical level is then calculated from the known titer of inhibitor. This method has been evaluated by assays of 75 samples from 22 patients with acquired or induced AHF inhibitors. In vivo plasma AHF activity correlated well with the calculated in vitro values. The assay provides reliable and accurate quantitation of factor VIII inhibitors enabling precise calculation of effective AHF dosage and monitoring of therapeutic response. The assay can be readily adapted to quantitation of other clotting factor inhibitors.

A Machine for the Determination of the Whole Blood Clotting Time

1970 ◽  
Vol 23 (03) ◽  
pp. 627-632
Author(s):  
D. L Watt
Keyword(s):  
Whole Blood ◽  
Blood Clotting ◽  
Heparin Therapy ◽  
Coagulation Disorders ◽  
Mechanical Device ◽  
Clotting Time ◽  
Normal Range ◽  
Glass Tubes ◽  
Blood Clotting Time

SummaryThe whole blood clotting time in glass tubes is widely used for the control of heparin therapy. In the investigation of coagulation disorders the whole blood clotting time is commonly done both in glass tubes and in tubes with non-wettable surfaces.This presentation concerns the development of a portable mechanical device, the Coagulation Timer, to perform this test. The end point is measured automatically by a photo-electric mechanism. Only a few minutes are required to draw blood and place samples in the machine, which may then be left unattended.Data are presented to show that results obtained using glass tubes in the Coagulation Timer correlate well with those of a technician using a modification of the Lee White method. Further data are presented establishing the normal range for the whole blood clotting time using polystyrene tubes in the Coagulation Timer.

COMPARISION OF THE DETECTION OF LUPUS ANTICOAGULANTS USING THREE DIFFERENT METHODS AND THE PRESENCE OF ANTI-CARDIOLIPIN ANTIBODIES

1987 ◽  
Author(s):  
A Criel ◽  
B Gilbert ◽  
A Van Hoof ◽  
M Hidajat ◽  
A Louwagie
Keyword(s):  
Elisa Test ◽  
Activated Partial Thromboplastin Time ◽  
Detection Methods ◽  
Recurrent Abortion ◽  
Clotting Time ◽  
Lupus Anticoagulants ◽  
Cardiolipin Antibodies ◽  
Tissue Thromboplastin ◽  
Kaolin Clotting Time

Lupus anticoagulant (LAC) is an antibody directed against phospholipids which prolongs in vitro clotting assays. Several detection methods have been described; however all give some different results. Recently ELISA and RIA assays have been developed which detect IgG and IgM anti-cardiolipin antibodies. The aim of our study was to compare three different LAC tests with an ELISA anti-cardiolipin test. The tests used were : kaolin clotting time (KCT or Exnertest), tissue thromboplastin inhibition test (TTI or Schleider test), activated partial thromboplastin time using a 50, 100, 200 fold dilution of the phospholipid preparation (APTT dilution test), and an IgG and IgM anti-cardiolipin ELISA test. 114 samples of patients suffering from diseases known to be accompanied with LAC antibodies (auto-immune diseases, recurrent abortion, thromboembolism, etc.) were studied. Positivity with one of the tests was found in 45 patients (39%). Patients with the diagnosis of SLE or otherimmune diseases showed the highest positivity (56%) whereas those with thromboembolism, recurrent abortion etc. were only positive in 27%.Among these 45 positive patients the TTI was positive in 41 cases (91 %);however in 10 cases (24 %) this was the only positivity found. The KCT test and the APTT dilution test were both positive in 18 cases (40 %). Anti-cardiolipin antibodies were found in 21 patients (47 %): IgG only in 12 (27 %), IgM only in 5 (11 %), both IgG and IgM in 2 (4 %); in 19 of these 21 patientsthe TTI was also positive.In our study the TTI test seems to be the most sensitive test but possibly also the test with the highest aspecific positivities. IgG and IgM anti-cardiolipin antibodies were less frequently found than expected.

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