Antiheparin Antibody: Preparation And Use As A Functional Probe

1981 ◽  
Author(s):  
S N Gitel ◽  
V M Medina ◽  
S Wessler
Keyword(s):  
Aqueous Solution ◽  
Binding Sites ◽  
Anticoagulant Activity ◽  
Red Cells ◽  
Heparin Binding ◽  
Antibody Preparation ◽  
Specific Antibodies ◽  
Coagulation Proteins ◽  
Heparin Complexes ◽  
Presence And Absence

Antiheparin antibodies were raised in 5 of 6 rabbits immunized sequentially with covalent complexes of ovalbumin-heparin and bovine IgG-heparin. Confirmation of the presence of heparin-specific antibodies in the antisera was based on: (1) antisera precipitation of BSA-heparin but not BSA alone, (2) antisera inhibition of heparin anticoagulant activity without precipitating heparin, (3) antisera precipitation of heparin-heparin complexes, and (4) antibody removal from the antisera by heparin- Sepharose. The antisera had hemagglutination titers between 1:10,000 and 1:50,000 when tested against tanned red cells labeled with BSA-heparin complex; whereas no hemagglutination occurred with tanned erythrocytes tagged with BSA. Heparin-heparin oligomers, prepared by carbo- diimide coupling in aqueous solution and retaining anticoagulant activity, precipitated in the presence of the antiheparin antibodies. Data indicating that heparin has separate binding sites for antithrombin 111 and thrombin were obtained by quantitating the heparin oligomer- antibody precipitate in the presence and absence of these two purified, heparin-binding, coagulation proteins.

Receptor Mediated Binding of the Fibrinolytic Components, Plasminogen and Urokinase, to Peripheral Blood Cells

1987 ◽  
Vol 58 (03) ◽  
pp. 936-942 ◽  
Author(s):  
Lindsey A Miles ◽  
Edward F Plow
Keyword(s):  
T Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
Binding Sites ◽  
Blood Cells ◽  
High Capacity ◽  
Red Cells ◽  
Peripheral Blood Cells ◽  
Cellular Functions ◽  
Fibrinolytic Proteins

SummaryGlu-plasminogen binds to platelets; the monocytoid line, U937, and the human fetal fibroblast line, GM1380 bind both plasminogen and its activator, urokinase. This study assesses the interaction of these fibrinolytic proteins with circulating human blood cells. Plasminogen bound minimally to red cells but bound saturably and reversibly to monocytes, granulocytes and lymphocytes with apparent Kd values of 0.9-1.4 μM. The interactions were of high capacity with 1.6 to 49 × 105 sites/cell and involved the lysine binding sites of plasminogen. Both T cells and non-rosetting lymphocytes and two B cell lines saturably bound plasminogen. Urokinase bound saturably to gianulocytes, monocytes, non-rosetting lymphocytes and a B cell line, but minimally to T cells, platelets and red cells. Therefore, plasminogen binding sites of high capacity, of similar affinities, and with common recognition specificities are expressed by many peripheral blood cells. Urokinase receptors are also widely distributed, but less so than plasminogen binding sites. The binding ol plasminogen and/ or urokinase to these cells may lead to generation of cell- associated proteolytic activity which contributes to a variety of cellular functions.

Pharmacokinetics of Full Length and Two-Domain Tissue Factor Pathway Inhibitor in Combination with Heparin in Rabbits

1993 ◽  
Vol 70 (03) ◽  
pp. 454-457 ◽  
Author(s):  
Claus Bregengaard ◽  
Ole Nordfang ◽  
Per Østergaard ◽  
Jens G L Petersen ◽  
Giorgio Meyn ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Tissue Factor Pathway Inhibitor ◽  
Anticoagulant Activity ◽  
Fold Increase ◽  
Volume Of Distribution ◽  
Full Length ◽  
Heparin Binding ◽  
Extrinsic Pathway ◽  
C Terminus ◽  
Tissue Factor Pathway

SummaryTissue factor pathway inhibitor (TFPI) is a feed back inhibitor of the initial activation of the extrinsic pathway of coagulation. In humans, injection of heparin results in a 2-6 fold increase in plasma TFPI and recent studies suggest that TFPI may be important for the anticoagulant activity of heparin. Full length (FL) TFPI, but not recombinant two-domain (2D) TFPI, has a poly cationic C-terminus showing very strong heparin binding. Therefore, we have investigated if heparin affects the pharmacokinetics of TFPI with and without this C-terminus.FL-TFPI (608 U/kg) and 2D-TFPI (337 U/kg) were injected intravenously in rabbits with and without simultaneous intravenous injections of low molecular weight heparin (450 anti-XaU/kg).Heparin decreased the volume of distribution and the clearance of FL-TFPI by a factor 10-15, whereas the pharmacokinetics of 2D-TFPI were unaffected by heparin. When heparin was administered 2 h following TFPI the recovery of FL-TFPI was similar to that found in the group receiving the two compounds simultaneously, suggesting that the releasable pool of FL-TFPI is removed very slowly in the absence of circulating heparin.

Comparison of the Non-Specific Binding of Unfractionated Heparin and Low Molecular Weight Heparin (Enoxaparin) to Plasma Proteins

1993 ◽  
Vol 70 (04) ◽  
pp. 625-630 ◽  
Author(s):  
Edward Young ◽  
Benilde Cosmi ◽  
Jeffrey Weitz ◽  
Jack Hirsh
Keyword(s):  
Molecular Weight ◽  
Unfractionated Heparin ◽  
Plasma Proteins ◽  
Low Molecular Weight Heparin ◽  
Specific Binding ◽  
Anticoagulant Activity ◽  
Factor Xa ◽  
Low Molecular Weight ◽  
Heparin Binding ◽  
Fixed Amount

SummaryThe non-specific binding of anticoagulantly-active heparin to plasma proteins may influence its anticoagulant effect. We used low affinity heparin (LAH) essentially devoid of anti-factor Xa activity to investigate the extent and possible mechanism of this non-specific binding. The addition of excess LAH to platelet-poor plasma containing a fixed amount of unfractionated heparin doubled the anti-factor Xa activity presumably because it displaces anticoagulantly-active heparin from plasma proteins. Although dextran sulfates of varying molecular weights also increased the anti-factor Xa activity, less sulfated heparin-like polysaccharides had no effect. These findings suggest that the ability to displace active heparin from plasma protein binding sites is related to charge and may be independent of molecular size. In contrast to its effect in plasma containing unfractionated heparin, there was little augmentation in anti-factor Xa activity when LAH was added to plasma containing low molecular weight heparin (LMWH), indicating that LMWH binds less to plasma proteins than unfractionated heparin. This concept is supported by studies comparing the anticoagulant activity of unfractionated heparin and LMWH in plasma with that in buffer containing antithrombin III. The anti-factor Xa activity of unfractionated heparin was 2-fold less in plasma than in the purified system. In contrast, LMWH had identical anti-factor Xa activity in both plasma and buffer, respectively. These findings may be clinically relevant because the recovered anti-factor Xa activity of unfractionated heparin was 33% lower in plasma from patients with suspected venous thrombosis than in plasma from healthy volunteers. The reduced heparin recovery in patient plasma reflects increased heparin binding to plasma proteins because the addition of LAH augmented the anti-factor Xa activity. In contrast to unfractionated heparin, there was complete recovery of LMWH added to patient plasma and little increase of anti-factor Xa activity after the addition of LAH. These findings may explain why LMWH gives a more predictable dose response than unfractionated heparin.

scholarly journals Arrangement of attachment-promoting, self-association, and heparin-binding sites in horse serum fibronectin.

1982 ◽  
Vol 257 (13) ◽  
pp. 7381-7387 ◽  
Author(s):  
R Ehrismann ◽  
D E Roth ◽  
H M Eppenberger ◽  
D C Turner
Keyword(s):  
Binding Sites ◽  
Horse Serum ◽  
Heparin Binding ◽  
Self Association

Photodegradation performance of 1,1,1-trichloroethane in aqueous solution: In the presence and absence of persulfate

2013 ◽  
Vol 215-216 ◽  
pp. 29-35 ◽  
Author(s):  
Xiaogang Gu ◽  
Shuguang Lu ◽  
Zhaofu Qiu ◽  
Qian Sui ◽  
Charles J. Banks ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Presence And Absence

Membrane ion channels and ionic hydration energies

1980 ◽  
Vol 211 (1182) ◽  
pp. 51-62 ◽  
Keyword(s):  
Aqueous Solution ◽  
Ion Channels ◽  
Binding Sites ◽  
Low Energy ◽  
Electrostatic Energy ◽  
Ionic Hydration ◽  
Ionic Size ◽  
Hydration Energies ◽  
Ordered Water

The difficulty of modelling ion channels in membranes due to the low electrostatic energy of small ions in aqueous solution is discussed. Models based upon ordered water cage structures are shown to provide suitable low energy binding sites which are selective both for unhydrated ionic size and valence. The barriers for motion of ions within these channels are shown to be low.

scholarly journals Fibronectin modulates formation of PF4/heparin complexes and is a potential factor for reducing risk of developing HIT

Blood ◽  
2019 ◽  
Vol 133 (9) ◽  
pp. 978-989 ◽  
Author(s):  
Krystin Krauel ◽  
Patricia Preuße ◽  
Theodore E. Warkentin ◽  
Catja Trabhardt ◽  
Sven Brandt ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Platelet Rich Plasma ◽  
Enzyme Linked Immunosorbent Assay ◽  
Heparin Binding ◽  
Plasma Fibronectin ◽  
Platelet Factor ◽  
Washed Platelet ◽  
Plasma Factor ◽  
Heparin Complexes ◽  
Patient Groups

Abstract Heparin-induced thrombocytopenia (HIT) is caused by platelet-activating anti–platelet factor 4 (PF4)/heparin antibodies. Platelet activation assays that use “washed” platelets are more sensitive for detecting HIT antibodies than platelet-rich plasma (PRP)–based assays. Moreover, heparin-exposed patients vary considerably with respect to the risk of PF4/heparin immunization and, among antibody-positive patients, the risk of subsequent “breakthrough” of clinical HIT with manifestation of thrombocytopenia. We used washed platelets and PRP, standard laboratory HIT tests, and physicochemical methods to identify a plasma factor interfering with PF4/heparin complexes and anti-PF4/heparin antibody–platelet interaction, thus explaining differences in functional assays. To investigate a modulating risk for PF4/heparin immunization and breakthrough of HIT, we also tested 89 plasmas from 2 serosurveillance trials. Fibronectin levels were measured in 4 patient groups exhibiting different degrees of heparin-dependent immunization and expression of HIT. The heat-labile plasma protein, fibronectin, inhibited PF4 binding to platelets in a dose-dependent fashion, particularly in washed (vs PRP) systems. Fibronectin also inhibited PF4/heparin binding to platelets, anti-PF4/heparin antibody binding to PF4/heparin complexes, and anti-PF4/heparin antibody–induced platelet activation as a result of PF4/heparin complex disruption. In addition, plasma fibronectin levels increased progressively among the following 4 patient groups: enzyme-linked immunosorbent assay (ELISA)+/serotonin-release assay (SRA)+/HIT+ < ELISA+/SRA+/HIT− ∼ ELISA+/SRA−/HIT− < ELISA−/SRA−/HIT−. Altogether, these findings suggest that fibronectin interferes with PF4/heparin complex formation and anti-PF4/heparin antibody–induced platelet activation. Reduced fibronectin levels in washed platelet assays help to explain the greater sensitivity of washed platelet (vs PRP) assays for HIT. More importantly, lower plasma fibronectin levels could represent a risk factor for PF4/heparin immunization and clinical breakthrough of HIT.

Chiral recognition in aqueous solution. Search for water-soluble chiral hosts with apolar binding sites

1986 ◽  
Vol 51 (17) ◽  
pp. 3270-3278 ◽  
Author(s):  
Yves Rubin ◽  
Klaus Dick ◽  
Francois Diederich ◽  
Taxiarchis M. Georgiadis
Keyword(s):  
Aqueous Solution ◽  
Binding Sites ◽  
Chiral Recognition ◽  
Water Soluble
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