Effects of Heparin Oligosaccharides with High Affinity for Antithrombin III in Experimental Venous Thrombosis

1982 ◽  
Vol 47 (03) ◽  
pp. 244-248 ◽  
Author(s):  
D P Thomas ◽  
Rosemary E Merton ◽  
T W Barrowcliffe ◽  
L Thunberg ◽  
U Lindahl
Keyword(s):  
Antithrombin Iii ◽  
Specific Activity ◽  
High Specific Activity ◽  
Factor Xa ◽  
Blood Levels ◽  
Thrombin Time ◽  
High Affinity ◽  
Very High

SummaryThe in vitro and in vivo characteristics of two oligosaccharide heparin fragments have been compared to those of unfractionated mucosal heparin. A decasaccharide fragment had essentially no activity by APTT or calcium thrombin time assays in vitro, but possessed very high specific activity by anti-Factor Xa assays. When injected into rabbits at doses of up to 80 ¼g/kg, this fragment was relatively ineffective in impairing stasis thrombosis despite producing high blood levels by anti-Xa assays. A 16-18 monosaccharide fragment had even higher specific activity (almost 2000 iu/mg) by chromogenic substrate anti-Xa assay, with minimal activity by APTT. When injected in vivo, this fragment gave low blood levels by APTT, very high anti-Xa levels, and was more effective in preventing thrombosis than the decasaccharide fragment. However, in comparison with unfractionated heparin, the 16-18 monosaccharide fragment was only partially effective in preventing thrombosis, despite producing much higher blood levels by anti-Xa assays.It is concluded that the high-affinity binding of a heparin fragment to antithrombin III does not by itself impair venous thrombogenesis, and that the anti-Factor Xa activity of heparin is only a partial expression of its therapeutic potential.

Heparin Therapy In Dispholidus Typus Envenomation: An Experimental Study

1981 ◽  
Author(s):  
B A Bradlow ◽  
P M Atkinson ◽  
M Rebello ◽  
M C Gaillard
Keyword(s):  
Antithrombin Iii ◽  
Factor Xa ◽  
Heparin Therapy ◽  
In Vivo Studies ◽  
Intrinsic Pathway ◽  
Heparin Resistance ◽  
Very High ◽  
Direct Activator

The coagulant action of Dispholidus typus venom was relatively resistant to inhibition by heparin in vitro. Heparin concentrations that inhibited coagulation due to either intrinsic pathway or Russell’s viper venom activation had little effect on coagulation due to D. Typus venom. At very high heparin to venom ratios, similar to ratios attainable in vivo this resistance could be overcome. The resistance could not be attributed to an abnormal thrombin produced by the venom since the thrombin produced from purified prothrombin by venom action reacted similarly to the thrombin produced by Factor Xa activation with purified antithrombin III. Thrombin produced from whole plasma by venom action also reacted similarly to physiological thrombin with antithrombin III in a crossed immunoelectrophoresis system. Incubation of venom with heparin and with antithrombin III did not alter the activities of these inhibitors. The heparin resistance may therefore be due to the fact that the venom is a direct activator of prothrombin. In vivo studies in rabbits indicated that heparin administered simultaneously with venom delayed the onset and reduced the severity of disseminated intravascular coagulation. Heparin administered later was much less effective. Early heparin therapy may be of value in human victims when specific antivenom is not available.

A Comparative Study Of Heparin And Heparin Fractions In Preventing Experimental Venous Thrombosis

1981 ◽  
Author(s):  
D P Thomas ◽  
T W Barrowcliffe ◽  
U Lindahl ◽  
L Thunberg ◽  
R E Merton ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Specific Activity ◽  
Binding Capacity ◽  
Weight Basis ◽  
Blood Levels ◽  
Thrombin Time ◽  
High Affinity ◽  
At Iii ◽  
Heparin Fractions

We have compared the relative efficacy in preventing venous thrombosis of an ordinary mucosal heparin, a low molecular weight (LMW) heparin fraction and a decasaccharide fragment with high affinity for AT III. We examined the extent to which all three preparations impaired the formation of serum-induced stasis thrombi in New Zealand White rabbits. The LMW fraction, despite having an in vitro potency by APTT half that of ordinary heparin (but comparable anti-Xa activity) was as effective as heparin on a weight basis in preventing thrombosis.Two minutes after intravenous injection of 30 μg/kg of the LMW fraction the mean blood level by anti-Xa clotting assay was 0.12 i.u./ml (range 0.08-0.21), which was sufficient to prevent thrombosis. In contrast, the decasaccharide fragment, which had a specific activity in vitro by anti-Xa assays of 1000-1300 i.u./mg, but essentially no activity by APTT or thrombin time assays, prevented stasis thrombi only when given at a dose of 100 μg/kg, giving blood levels in excess of 0.3 i.u./ml by anti-Xa assays.It is concluded that in this experimental model a decasaccharide fragment, despite having a very high affinity for AT III, was less effective on a weight for weight basis than either ordinary heparin or a LMW fraction in preventing venous thrombosis. This suggests that while a sufficiently high anti-Xa activity can alone prevent venous thrombosis, the effectiveness of heparin as an antithrombotic drug does not depend solely on its AT III-binding capacity.

Studies in Man and Experimental Animals of a Low Molecular Weight Heparin Fraction

1981 ◽  
Vol 45 (03) ◽  
pp. 214-218 ◽  
Author(s):  
D P Thomas ◽  
R E Merton ◽  
W E Lewis ◽  
T W Barrowcliffe
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Specific Activity ◽  
Ex Vivo ◽  
High Specific Activity ◽  
Factor Xa ◽  
In Vivo Studies ◽  
Low Molecular Weight

SummaryIn vitro and in vivo studies were carried out on a commercially prepared low molecular weight heparin fraction. By APTT assay the fraction had a specific activity of half that of unfractionated mucosal heparin, yet retained full potency by anti-Xa assay (both clotting and chromogenic substrate). When administered intravenously to human volunteers, the anti-Xa/APTT ratio remained the same as it was in vitro. However, after subcutaneous injection, the ratio increased and anti-Xa activity could not be fully neutralized ex vivo by PF4. The fraction was as effective as unfractionated heparin in preventing experimental serum-induced thrombosis, suggesting that a heparin fraction with high specific activity by anti-Factor Xa assay compared to APTT activity may be an effective drug for the prophylaxis of venous thrombosis.

Corticosteroid alteration of carboplatin-induced hematopoietic toxicity in a murine model

Blood ◽  
1995 ◽  
Vol 86 (12) ◽  
pp. 4493-4499 ◽  
Author(s):  
J Rinehart ◽  
L Keville ◽  
J Measel ◽  
AM Spiekerman ◽  
K Burke
Keyword(s):  
Bone Marrow ◽  
Specific Activity ◽  
High Specific Activity ◽  
Chemotherapeutic Agents ◽  
Optimum Dose ◽  
Blood Levels ◽  
Pharmacokinetic Studies ◽  
Hematopoietic Toxicity

Corticosteroids exhibit extensive hematopoietic effects both in vitro and in vivo. Some of the previously studied effects suggested that corticosteroids may alter hematopoietic toxicity of chemotherapeutic agents. In this study, we examined (1) the optimum dose and schedule of cortisone acetate (CA) to reduce hematopoietic toxicity of carboplatin (CB) and (2) possible mechanisms involved in this protective effect. CA given subcutaneously at 0.5 mg/d per mouse for 7 days before CB reduced CB-induced mortality due to neutropenia from 88% in controls to 14% in CA-treated mice (P < .05). Lower CA doses were not effective. Three days of pretreatment (but not 1 day) was as effective as 7 days. CA given after CB had no effect on mortality. Pharmacokinetic studies of CA at 0.5 mg per mouse demonstrated blood levels of cortisol achievable in patients (peak level, 82 micrograms/dL). CA treatment markedly reduced spleen cell number and colony-forming units- granulocyte/macrophage (CFU-GM) as well as bone marrow CFU-GM. Bone marrow CFU-GM removed from CA-treated mice demonstrated increased resistance to platinum and increased resistance to high specific activity 3H-thymidine. These findings suggest that treatment of mice with CA induces cellular resistance of hematopoietic precursors to platinum and, thus, reduces CB hematotoxicity. CA or other corticosteroids may be useful in reducing clinical toxicity of CB.

Anticoagulant Properties of Three Mucopolysaccharides Used in Rheumatology

1983 ◽  
Vol 50 (03) ◽  
pp. 652-655 ◽  
Author(s):  
F Bauer ◽  
P Schulz ◽  
G Reber ◽  
C A Bouvier
Keyword(s):  
Factor Xa ◽  
Degenerative Joint Disease ◽  
Joint Disease ◽  
Thrombin Time ◽  
Coagulation Tests ◽  
Amplification System ◽  
Relative Potencies ◽  
In Vivo Administration

SummaryThree mucopolysaccharides (MPS) used in the treatment of degenerative joint disease were compared to heparin to establish their relative potencies on 3 coagulation tests, the aPTT, the antifactor X a activity and the dilute thrombin time. One of the compounds, Arteparon®, was one fourth as potent as heparin on the aPTT, but had little or no influence on the 2 other tests. Further in vitro studies suggested that Arteparon® acted at a higher level than factor Xa generation in the intrinsic amplification system and that its effect was independent of antithrombin III. In vivo administration of Arteparon® confirmed its anticoagulant properties, which raises the question of the clinical use of this MPS.

Novel concatameric heparin-binding peptides reverse heparin and low-molecular-weight heparin anticoagulant activities in patient plasma in vitro and in rats in vivo

Blood ◽  
2004 ◽  
Vol 103 (4) ◽  
pp. 1356-1363 ◽  
Author(s):  
Barbara P. Schick ◽  
David Maslow ◽  
Adrianna Moshinski ◽  
James D. San Antonio
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Tandem Repeats ◽  
Factor Xa ◽  
Low Molecular Weight ◽  
Heparin Binding ◽  
High Affinity ◽  
Binding Peptides

Abstract Patients given unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) for prophylaxis or treatment of thrombosis sometimes suffer serious bleeding. We showed previously that peptides containing 3 or more tandem repeats of heparin-binding consensus sequences have high affinity for LMWH and neutralize LMWH (enoxaparin) in vivo in rats and in vitro in citrate. We have now modified the (ARKKAAKA)n tandem repeat peptides by cyclization or by inclusion of hydrophobic tails or cysteines to promote multimerization. These peptides exhibit high-affinity binding to LMWH (dissociation constant [Kd], ≈ 50 nM), similar potencies in neutralizing anti–Factor Xa activity of UFH and enoxaparin added to normal plasma in vitro, and efficacy equivalent to or greater than protamine. Peptide (ARKKAAKA)3VLVLVLVL was most effective in all plasmas from enoxaparin-treated patients, and was 4- to 20-fold more effective than protamine. Several other peptide structures were effective in some patients' plasmas. All high-affinity peptides reversed inhibition of thrombin-induced clot formation by UFH. These peptides (1 mg/300 g rat) neutralized 1 U/mL anti–Factor Xa activity of enoxaparin in rats within 1 to 2 minutes. Direct blood pressure and heart rate measurements showed little or no hemodynamic effect. These heparin-binding peptides, singly or in combination, are potential candidates for clinical reversal of UFH and LMWH in humans.

scholarly journals Molecular Docking, Computational, and Antithrombotic Studies of Novel 1,3,4-Oxadiazole Derivatives

2018 ◽  
Vol 19 (11) ◽  
pp. 3606 ◽  
Author(s):  
Majda Batool ◽  
Affifa Tajammal ◽  
Firdous Farhat ◽  
Francis Verpoort ◽  
Zafar Khattak ◽  
...  
Keyword(s):  
Factor Xa ◽  
Clot Lysis ◽  
Clotting Time ◽  
Reference Drug ◽  
Docking Score ◽  
High Affinity ◽  
Oxadiazole Derivatives ◽  
Inhibitory Potential

A new series of 1,3,4-oxadiazoles derivatives was synthesized, characterized, and evaluated for their in vitro and in vivo anti-thrombotic activity. Compounds (3a–3i) exhibited significant clot lysis with respect to reference drug streptokinase (30,000 IU), and enhanced clotting time (CT) values (130–342 s) than heparin (110 s). High affinity towards 1NFY with greater docking score was observed for the compounds (3a, 3i, 3e, 3d, and 3h) than the control ligand RPR200095. In addition, impressive inhibitory potential against factor Xa (F-Xa) was observed with higher docking scores (5612–6270) with Atomic Contact Energy (ACE) values (−189.68 to −352.28 kcal/mol) than the control ligand RPR200095 (Docking score 5192; ACE −197.81 kcal/mol). In vitro, in vivo, and in silico results proposed that these newly synthesized compounds might be used as anticoagulant agents.

scholarly journals Effect ofToona microcarpaHarms Leaf Extract on the Coagulation System

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Hao Chen ◽  
Min Jin ◽  
Yi-Fen Wang ◽  
Yong-Qing Wang ◽  
Ling Meng ◽  
...  
Keyword(s):  
Leaf Extract ◽  
Factor Xa ◽  
Adenosine Diphosphate ◽  
Coagulation System ◽  
Dependent Manner ◽  
Thrombin Time ◽  
Antithrombotic Agent ◽  
Thrombin Activity

Toona microcarpaHarms is a tonic, antiperiodic, antirheumatic, and antithrombotic agent in China and India and an astringent and tonic for treating diarrhea, dysentery, and other intestinal infections in Indonesia. In this study, we prepared ethyl-acetate extract from the air-dried leaves ofToona microcarpaHarms and investigated the anticoagulant activitiesin vitroby performing activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) assays. Antiplatelet aggregation activity of the extract was examined using adenosine diphosphate (ADP), collagen, and thrombin as agonists, and the inhibitions of factor Xa and thrombin were also investigated. Bleeding and clotting times in mice were used to determine its anticoagulant activitiesin vivo. It is found thatToona microcarpaHarms leaf extract (TMHE) prolonged APTT, PT, and TT clotting times in a dose-dependent manner and significantly inhibited platelet aggregation induced by thrombin, but not ADP or collagen. Clotting time and bleeding time assays showed that TMHE significantly prolonged clotting and bleeding timesin vivo. In addition, at the concentration of 1 mg/mL, TMHE inhibited human thrombin activity by 73.98 ± 2.78%. This is the first report to demonstrate that THME exhibits potent anticoagulant effects, possibly via inhibition of thrombin activity.

scholarly journals In Vitro Characterization of Rabbit Thrombin, Antithrombin III, and Thrombin-Antithrombin III Complex, and Determination of Their Survival Times in Vivo

1977 ◽  
Author(s):  
Christine N. Vogel ◽  
Kingdon S. Henry ◽  
Roger L. Lundblad
Keyword(s):  
Gel Electrophoresis ◽  
Half Life ◽  
Antithrombin Iii ◽  
Specific Activity ◽  
Sodium Dodecyl ◽  
In Vivo Studies ◽  
Survival Times ◽  
At Iii

Our intention is to study the interaction of rabbit thrombin with antithrombin III (AT-III) in vitro and in vivo. After activation of crude prothrombin with tissue thromboplastin and CaCl2, thrombin was purified and showed two species of thrombin with molecular weights of 36,000 and 39,000 daltons as determined by sodium dodecyl sulfate discontinuous gel electrophoresis. Rabbit AT-III was purified using a heparin agarose column and had a molecular weight of 55,000 daltons. The inhibition of thrombin by AT-III was followed by fibrinogen clotting assays and an AT-III-thrombin complex was observed on gel electrophoresis. For the in vivo studies both thrombin and AT-III were radiolabelled with Na125i using the solid state lactoperoxidase method and retained 99% of the pre-iodinated specific activity. Radiolabelled thrombin and a radiolabelled AT-III-thrombin complex were injected into different rabbits. The rate of removal of both was very similar with a half-life of approximately 9 hours. When radiolabelled AT-III was injected, the half-life was approximately 60 hours. Since the disappearance rate of thrombin more closely approximates that of the preformed AT-III-thrombin complex and is clearly shorter than the turnover rate of AT-III, the possibility is raised that thrombin combines in vivo with a native inhibitor such as AT-III and may in fact be removed from the circulation as a complex rather than as a native molecule.

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.

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