Non-Decalcified Barium Sulfate-Adsorbed Plasma A Potentially Useful Reagent for Studying Blood Clotting, Platelets or Complement

1982 ◽  
Vol 47 (02) ◽  
pp. 182-184 ◽  
Author(s):  
Marjorie B Zucker ◽  
John Owen
Keyword(s):  
Factor Viii ◽  
Vitamin K ◽  
Divalent Cation ◽  
Barium Sulfate ◽  
Blood Clotting ◽  
Factor V ◽  
Fibrinopeptide A ◽  
Factor Viii Activity ◽  
Clotting Factors ◽  
Plasma Factor

SummaryPlasma was prepared by rapid centrifugation of native blood followed by adsorption of vitamin K-dependent clotting factors with BaSO4. Compared to fresh citrated plasma, BaSO4-treated plasma contained about 80% of factor V and factor VIII and the same concentration of fibrinopeptide A. Assays were also carried out after overnight incubation of citrated plasma and BaSO4-adsorbed plasma with and without added citrate and compared to assays of fresh citrated plasma. Factor V decreased to about 25% in both citrated samples, factor VIII decreased to 45% in both samples of BaSO4-treated plasma, and fibrinopeptide A did not change. Thus loss of factor V activity depended on reduction in divalent cation concentration whereas loss of factor VIII activity may have resulted from effects of early traces of thrombin.

scholarly journals Suppression of an Antibody to Factor VIII by a Combination of Factor VIII and Cyclophosphamide

Blood ◽  
1971 ◽  
Vol 37 (4) ◽  
pp. 381-387 ◽  
Author(s):  
DAVID GREEN
Keyword(s):  
Factor Viii ◽  
Vaginal Bleeding ◽  
Blood Clotting ◽  
Intravenous Dose ◽  
Clotting Time ◽  
Factor Viii Activity ◽  
Plasma Factor ◽  
History Of ◽  
Blood Clotting Time

Abstract A 54-year-old woman with a 20-year history of generalized, severe psoriasis presented with diffuse ecchymoses, melena, and vaginal bleeding. The whole blood clotting time was 59 minutes and the plasma factor VIII concentration was less than 1 per cent of normal. Incubation of the patient’s plasma with cryoprecipitate containing one unit of factor VIII resulted in the rapid disappearance of factor VIII activity from the mixture. The major antifactor VIII activity of the patient’s plasma was associated with an immunoglobulin of the IgG class. The patient was initially treated with a combination of methotrexate, azathioprine, and cyclophosphamide. No improvement occurred, and after 6 weeks of therapy the drugs were discontinued. Eight months later, she presented with an expanding sublingual hematoma. Bleeding was controlled by the rapid administration of 10,000 units of factor VIII, and an intravenous dose of cyclophosphamide given concurrently resulted in a prompt decline in antibody titer. Factor VIII levels subsequently became normal and have remained normal during 7 months of follow-up observation.

Characterization of Clotting Factors Associated with Blood Platelets after Gel Filtration

1973 ◽  
Vol 30 (02) ◽  
pp. 289-298
Author(s):  
Oddvar Tangen ◽  
Eva B. Lestrup ◽  
Herbert J. Berman
Keyword(s):  
Factor Viii ◽  
Blood Platelets ◽  
Gel Filtration ◽  
Factor Xa ◽  
Factor V ◽  
Factor X ◽  
Factor Viii Activity ◽  
Clotting Factors ◽  
Platelet Surface ◽  
Filtration Factor

SummaryAggregation of human and rabbit gel filtered platelets (GFP) has been studied in presence of Ca2+, activated factor X (Xa) and different plasma preparations. It was found that factor Xa by itself is not a platelet aggregating agent. However, the platelets aggregated immediately when platelet poor plasma (PPP) was added to a mixture of GFP, Ca2+ and factor Xa. Aggregation also occurred immediately when factor V-deficient plasma was substituted for PPP, but not when factor II-deficient plasma was used. In the absence of factor Xa, aggregation occurred on addition of factor V- or VIII-deficient plasma, but only after some delay. The platelet aggregation experiments and experiments with centrifugations and resuspensions of the platelets, clotting experiments, and gel filtration of platelet free plasma (PEP) led to the following conclusions : Factors II and X are totally removed from the platelets by gel filtration, factor V is closely associated with the platelet surface, and part of the factor VIII-activity in the plasma is eluted together with the GFP without being associated with the platelets. This factor VIII-activity belonged to an extremely large molecule or molecular complex with a Mw in the order of 2 - 5 · 107.

Fibrinogen and its Derivatives: Cofactors in the Intrinsic Generation of Thrombin

1976 ◽  
Vol 35 (02) ◽  
pp. 305-313 ◽  
Author(s):  
D.C Triantaphyllopoulos ◽  
L.T Ryan
Keyword(s):  
Factor Viii ◽  
Vitamin K ◽  
Bovine Serum ◽  
Thrombin Generation ◽  
Factor V ◽  
Simultaneous Addition ◽  
Lower Effect

SummaryThe simultaneous addition of suboptimal concentrations of factor VIII and intact or plas-min-lysed fibrinogen into mixtures of the vitamin K dependent factors, phospholipids, adsorbed bovine serum (supplier of factor V) and calcium, increased the amount of thrombin which was generated three to twenty times over the sum of the amounts which were generated when factor VIII, or fibrinogen, or its derivatives were added separately into the thrombin generating mixture. When factor VIII was added together with both fibrinogen and its derivatives, the amount of thrombin generated was even greater, about 130% larger than the amount which was generated in the presence of equal concentrations of only intact fibrinogen plus factor VIII. Addition of albumin instead of fibrinogen or its derivatives has a similar but significantly lower effect on thrombin generation. It appears, therefore, that both intact fibrinogen and its plasminolytic derivatives, singly or in combination, and to a lesser extent albumin, act as cofactors in the reaction which is regulated by factor VIII.

Kinetic Aspects of the Interaction of Blood-Clotting Enzymes

1968 ◽  
Vol 20 (01/02) ◽  
pp. 078-087 ◽  
Author(s):  
H. C Hemker ◽  
A. D Muller
Keyword(s):  
Vitamin K ◽  
Blood Clotting ◽  
Experimental Results ◽  
Factor X ◽  
Clotting Factors ◽  
Vitamin K Deficiency ◽  
K Deficiency

SummaryPIVKA, the circulating anticoagulant protein found in vitamin K deficiency can, on kinetical grounds, be recognized as an analogue of factor X. The existence of analogues of other vitamin K-dependent clotting factors cannot be ruled out, but need not be assumed to explain the experimental results.

Heparin, Protamine and Polybrene

1965 ◽  
Vol 13 (02) ◽  
pp. 550-560 ◽  
Author(s):  
Anthony Britten
Keyword(s):  
Factor Viii ◽  
Incubation Mixture ◽  
Factor V ◽  
Factor Viii Activity ◽  
Rapid Loss

SummaryThe effects of incubating heparin, protamine or Polybrene with plasma were studied. All three drugs cause rapid loss of factor V from decalcified plasma, while Polybrene also accelerates the loss of factor VIII activity. These changes are related to temperature, the period of incubation and the dose of the drug used, and can be partially prevented by inclusion of neutralizing doses of the appropriate antagonist in the incubation mixture.The implications of these findings are discussed.

scholarly journals Further Experience on the Effect of High Pre-Donation Factor VIII Levels in Blood Donors on the Factor VIII Content of Small-Pool Fractions

1977 ◽  
Author(s):  
H. Beeser ◽  
H. Eqli
Keyword(s):  
Factor Viii ◽  
High Plasma ◽  
Activity Levels ◽  
Factor Viii Activity ◽  
Factor Viii Level ◽  
Plasma Factor ◽  
Viii Level ◽  
Factor Viii Concentrates ◽  
Small Pool ◽  
Concentrate Preparation

Because of the well known wide normal range of the factor VIII activity between 60 to 170% I man, selecting of donors with high activity levels would be of advantaae for the preparation of factor VIII concentrates. This is especially true for preparing small-pool fractions, as for technical reasons the final product cannot be controlled for its factor VIII content. In preliminary investigations, we reported on elsewhere, high factor VIII activity in donors estimated before a donation had been rarely reproducible before a second donation after 8-12 weeks. So as a preliminary result of finding a donor’s factor VIII level varying from donation to donation selecting of plasmas with high factor VIII content for concentrate preparation could only be establishedby re-estimating the activity before each donation. Proceeding in this way would be much too troublesome. To get more reliable information whether a healthy subject’s high factor VIII plasma level is distinctly varying or rather constant we assayed the plasma of 200 donors with factor VIII activity > 120% two times more before donation. The results confirmed our preliminary findings, especially the fact that a high plasma factor VIII activity in experienced donors was rarely reproducible when re-estimated before a second and third donation. As a consequence selecting of donors with high factor VIII procoaqulant activity for preparing small-pool factor VIII concentrates is impracticable.

scholarly journals The Activation of Factor VIII by Thrombin

Blood ◽  
1965 ◽  
Vol 26 (4) ◽  
pp. 500-509 ◽  
Author(s):  
A. H. ÖZGE-ANWAR ◽  
G. E. CONNELL ◽  
J. F. MUSTARD
Keyword(s):  
Factor Viii ◽  
Human Factor ◽  
Experimental Approach ◽  
Factor Viii Activity ◽  
Clotting Factors ◽  
Activation Effect ◽  
Activation Reaction ◽  
Human Factor Viii

Abstract The activation of human factor VIII by thrombin has been demonstrated by a new experimental approach. This method permitted investigation of the interaction of thrombin and factor VIII in the absence of most other clotting factors. The activation effect of thrombin is susceptible to inhibition by diisopropylfluorophosphate. Trypsin cannot replace thrombin in the activation reaction, and it destroys factor VIII activity rapidly.

Presence Of Receptor For Activated Factor VIII On The Surface Of Released Platelets

1981 ◽  
Author(s):  
K Brodén ◽  
L-O Andersson
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Factor X ◽  
Factor Viii Activity ◽  
Platelet Receptor ◽  
Plasma Factor ◽  
Centrifuge Tube ◽  
Dilute Suspension ◽  
Von Willebrand ◽  
Willebrand Factor

In normal plasma Factor VIII activity is associated with a series of high molecular weight glycoprotein complexes also containing von Willebrand Factor related activities. To study the possible binding of various forms of Factor VIII to released platelets, a solution containing Factor VIII was mixed with a dilute suspension of platelets, which were released by addition of collagen. After 10 minutes of incubation the mixture was layered over 1.5 ml of 30% human serum albumin solution in a centrifuge tube and subjected to centrifugation at 7,000xg. Fractions were collected and analyzed for Factor VIII activity and phospholipid-related procoagulant activity. When purified Factor VUI/von Willebrand Factor complex was studied no significant association between the Factor VIII activity and the platelets were found. When purified Factor VUI/von Willebrand Factor complex was activated with 10-3 units/ml of thrombin and then tested, the main part of the Factor VIII activity became associated with the platelets. Even at very low platelet counts this binding was clearly detectable. The binding occurred both in the presence and in the absence of Ca2+. Thus released platelets bind thrombin-activated Factor VIII but not the Factor VUI/von Willebrand Factor complex. It is known that activation of Factor VIII by thrombin causes dissociation of the Factor VIII from the von Willebrand Factor part of the complex. The data obtained indicate that this dissociation is necessary in order to get the Factor VIII to bind to the platelet receptor. It may work as an amplification mechanism where the first traces of Thrombin formed upon initiation of coagulation dissociates Factor VIII from von Willebrand Factor, followed by binding to receptor on released platelets and formation of Factor X activator complex on the surface of the platelets.

An Improved Method of Making Factor VIII Concentrates

1979 ◽  
Author(s):  
G. Rock ◽  
D.S. Palmer ◽  
E.S. Tackaberry ◽  
M. Wickerhauser
Keyword(s):  
Factor Viii ◽  
Present Method ◽  
Batch Preparation ◽  
Improved Method ◽  
Factor Viii Activity ◽  
Peg 4000 ◽  
Plasma Factor ◽  
Factor Viii Concentrates ◽  
The Cost ◽  
Plasma Activity

The yields from batch preparation of Factor VIII concentrates can be substantially improved by collecting the blood into heparin rather than into CPD as anticoagulant. The resultant cryoprecipitate contains 78 ± 9% of the original plasma activity if 20 mls of supernatant per litre of starting plasma are left with the cryoprecipitate to maintain heparin levels. This cryoprecipitate was further purified by solubilization at 37°C for 5 minutes using 40 cc of saline per litre of starting plasma. This preparation was adjusted to pH 6.3 and 4.5% PEG 4000. Then, after removal of the precipitate by centrifugaron, the 4.5% PEG supernatant is adjusted to pH 6.0 and 11% PEG. The 11% PEG precipitate obtained after centrifugation is resolubilized in 1/100th the original plasma volume with buffer (0.1 M glycine, 20 mM citrate, 0.15 H saline) containing 1 unit of heparin per ml. Experiments using plasma pools containing 1-15 donor units gave yields ranging from 390-490 plasma Factor VIII equivalents per litre of the starting plasma. The final product retains an average of 90% of the initial Factor VIII activity after 24 hours at 22°C. It is believed that the present method could substantially reduce the cost of producing Factor VIII concentrates.

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