THE CHANGES OF FACTOR VIII ANTIGEN DURING THE COAGULATION PROCESS

1987 ◽  
Author(s):  
I Tanaka ◽  
A Yoshioka ◽  
T Fujiwara ◽  
H Nakai ◽  
H Fukui
Keyword(s):  
Monoclonal Antibodies ◽  
Serum Level ◽  
Factor Viii ◽  
Blood Coagulation ◽  
Whole Blood ◽  
Initial Phase ◽  
Blood Clotting ◽  
Coagulation Process ◽  
The Mean

The changes of factor VIII (F. VIII) during blood coagulation process is still controversial. We analyzed the F. VIII antigen (F. VIII:Ag) at various intervals of in vitro blood clotting by immunoassays using polyclonal and different kinds of monoclonal antibodies to F. VIII.We used two immunoassays, an immunoradiometric assay (IRMA) and an enzyme-linked immunosorbent assay (ELISA). The IRMA was performed by the method of Peake et al. using high-titer allo-antibodies to F. VIII. The ELISA was performed by two-site solid phase system consisting of alloantibodies as the first and one of three kinds of monoclonal antibodies (NMC-VIII/1, -VIII/2 or C5*) as the second antibody. Using the immunoblotting technique, it had been shown that NMC-VIII/1 recognized the 80/79 kDa derived from C-terminus and both NMC-VIII/2 and C5 recognized 54 kDa derived from N-terminus.The mean levels of F. VIII:Ag in 20 normal plasmas and sera were 0.97±0.23 U/ml and 0.68±0.21 U/ml, respectively using the polyclonal IRMA. The mean levels of F. VIII:Ag in normal sera were 0.14±0.05 U/ml (NMC-VIII/1), 0.71±0.21 U/ml (NMC-VIII/2), and 0.012±0.02 U/ml (C5) using the monoclonal ELISAs. In the initial phase of whole blood coagulation in vitro, the increase of F. VIII: Ag was observed by the polyclonal IRMA as F. VIII:C assayed by a one-stage clotting method increased. On the other hand, the F. VIII:Ag assayed by NMC-VIII/1 or C5 monoclonal ELISA progressively decreased to the serum level within 30 min. The F. VIII:Ag by NMC-VIII/2 declined to the serum level at a slow rate. In order to study the influence of thrombin on F. VIIIrAg during blood clotting, a synthesized selective thrombin inhibitor (MD-805, Mitsubishi Chemical Ind.) was previously added to the whole blood tested. The changes of F. VIII:Ag with MD-805 by the monoclonal ELISAs were almost the same as those without MD-805.It is suggested that in the whole blood coagulation process the antigenicity of F. VIII molecule changes in the initial phase (within 30 min.), but that thrombin does not play the main role of the phenomenon in physiological concentration.*C5 was kindly supplied from Dr. C. Fulcher (Scripps Clinic and Research Foundation, USA)

The Natural Course of Defibrination Syndrome Caused by Echis Colorata Venom in Man

1974 ◽  
Vol 31 (03) ◽  
pp. 420-428 ◽  
Author(s):  
M Fainaru ◽  
S Eisenberg ◽  
N Manny ◽  
C Hershko
Keyword(s):  
Factor Viii ◽  
Blood Coagulation ◽  
Major Bleeding ◽  
Renal Damage ◽  
Specific Treatment ◽  
Natural Course ◽  
Factor V ◽  
Thrombocyte Count

SummaryThe natural course of defibrination syndrome caused by Echis colorata venom (ECV) in five patients is reported. All patients developed afibrinogenemia within six hours after the bite. Concomitantly a depression in factor V was recorded. Factor VIII and thrombocyte count in blood were normal in most patients. In the light of the known effects of ECV on blood coagulation in vivo and in vitro it is concluded that the afibrinogenemia is due to intravascular clotting.Four patients had transient renal damage, manifested by oliguria, azotemia, albuminuria and cylindruria, ascribed to microthrombi in the renal glomeruli.After the bite, the natural course was benign, no major bleeding was observed, and all signs of coagulopathy reverted to normal within 7 days. Therefore we recommend no specific treatment for this condition. In the case of heavily bleeding patients, administration of antiserum against ECV and/or heparin should be considered.

scholarly journals Inhibition of human coagulation factor VIII by monoclonal antibodies. Mapping of functional epitopes with the use of recombinant factor VIII fragments

1989 ◽  
Vol 263 (1) ◽  
pp. 187-194 ◽  
Author(s):  
A Leyte ◽  
K Mertens ◽  
B Distel ◽  
R F Evers ◽  
M J M De Keyzer-Nellen ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Factor Viii ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Procoagulant Activity ◽  
Coagulation Factor Viii ◽  
Coagulation Cascade ◽  
Restriction Enzyme Digestion ◽  
Proteolytic Activation

The epitopes of four monoclonal antibodies against coagulation Factor VIII were mapped with the use of recombinant DNA techniques. Full-length Factor VIII cDNA and parts thereof were inserted into the vector pSP64, permitting transcription in vitro with the use of a promoter specific for SP6 RNA polymerase. Factor VIII DNA inserts were truncated from their 3′-ends by selective restriction-enzyme digestion and used as templates for ‘run-off’ mRNA synthesis. Translation in vitro with rabbit reticulocyte lysate provided defined radiolabelled Factor VIII fragments for immunoprecipitation studies. Two antibodies are shown to be directed against epitopes on the 90 kDa chain of Factor VIII, between residues 712 and 741. The 80 kDa chain appeared to contain the epitopes of the other two antibodies, within the sequences 1649-1778 and 1779-1840 respectively. The effect of antibody binding to these sequences was evaluated at two distinct levels within the coagulation cascade. Both Factor VIII procoagulant activity and Factor VIII cofactor function in Factor Xa generation were neutralized upon binding to the region 1779-1840. The antibodies recognizing the region 713-740 or 1649-1778, though interfering with Factor VIII procoagulant activity, did not inhibit in Factor Xa generation. These findings demonstrate that antibodies that virtually inhibit Factor VIII in coagulation in vitro are not necessarily directed against epitopes involved in Factor VIII cofactor function. Inhibition of procoagulant activity rather than of cofactor function itself may be explained by interference in proteolytic activation of Factor VIII. This hypothesis is in agreement with the localization of the epitopes in the proximity of thrombin-cleavage or Factor Xa-cleavage sites.

The Haemocompatibility of Biomaterials In Vitro: Investigations on the Mechanism of the Whole-blood Clot Formation Test

1992 ◽  
Vol 20 (3) ◽  
pp. 390-395 ◽  
Author(s):  
Thomas Groth ◽  
Katrin Derdau ◽  
Frank Strietzel ◽  
Frank Foerster ◽  
Hartmut Wolf
Keyword(s):  
Whole Blood ◽  
Blood Clotting ◽  
Blood Clot ◽  
Formation Rate ◽  
Clot Formation ◽  
Coagulation Cascade ◽  
Contact Activation ◽  
Human Fibrinogen ◽  
Static Conditions

Twenty years ago Imai & Nose introduced a whole-blood clotting test for the estimation of haemocompatibility of biomaterials in vitro In our paper a modification of this assay is described and the mechanism of clot formation further elucidated. It was found that neither the inhibition of platelet function nor the removal of platelets from blood significantly changed the clot formation rate on glass and polyvinyl chloride in comparison to the rate tor whole blood. Scanning electron microscopy demonstrated that platelets were not involved in clot formation near the blood/biomaterial interface. Thus, it was concluded that the system of contact activation of the coagulation cascade dominates during clot formation under static conditions. The latter conclusion was supported by the fact that preadsorption of human serum albumin or human fibrinogen onto the glass plates used, decreased the clot formation rate in the same manner.

Results of in vitro whole blood coagulation assays using ROTEM and the flow-chamber T-TAS system are affected by hematocrit

2020 ◽  
Vol 194 ◽  
pp. 98-100
Author(s):  
Anna Ågren ◽  
Gustaf Edgren ◽  
Paul Hjemdahl ◽  
Gunilla Gryfelt ◽  
Anders Östlund ◽  
...  
Keyword(s):  
Blood Coagulation ◽  
Whole Blood ◽  
Flow Chamber ◽  
Coagulation Assays

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.

Granulokinetics in normal dogs

1964 ◽  
Vol 206 (1) ◽  
pp. 83-88 ◽  
Author(s):  
S. O. Raab ◽  
J. W. Athens ◽  
O. P. Haab ◽  
D. R. Boggs ◽  
H. Ashenbrucker ◽  
...  
Keyword(s):  
Whole Blood ◽  
Turnover Rate ◽  
Half Time ◽  
Total Blood ◽  
Mean Values ◽  
Hexadimethrine Bromide ◽  
The Mean ◽  
Blood Granulocyte ◽  
Number Of Cells

Dog granulocytes were labeled in vitro with radioactive diisopropylfluorophosphate (DFP32) and then returned to the circulation of the donor. Granulocytes were separated from whole blood by utilizing hexadimethrine bromide as the sedimenting agent and saponin as a lysing agent. The labeled granulocytes disappeared from the circulation in an exponential fashion with a mean (±1 sd) half-time disappearance of 5.6 ± 0.95 hr. The size of the total blood granulocyte ( TBGP), circulating granulocyte ( CGP), and marginal granulocyte ( MGP) pools, and the granulocyte turnover rate ( GTR) were measured in 31 normal, unanesthetized dogs. The mean values ± 1 sd, expressed as number of cells x107/kg body wt., were as follows: TBGP, 102 ± 34.8; CGP, 54 ± 20.7; MGP, 48 ± 23.4; and GTR, 305 ± 111.5 cells/kg day. The values observed in anesthetized and in unanesthetized, splenectomized dogs were not significantly different from the above values.

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