Coagulant and Anticoagulant Actions of Australian Snake Venoms

1983 ◽  
Vol 50 (03) ◽  
pp. 707-711 ◽  
Author(s):  
Lorraine R Marshall ◽  
Richard P Herrmann
Keyword(s):  
Systematic Study ◽  
Fibrinolytic Activity ◽  
Anticoagulant Activity ◽  
Coagulation System ◽  
Factor V ◽  
Snake Venoms ◽  
Plasma Coagulation ◽  
Fibrinogenolytic Activity ◽  
Minimal Evidence

SummaryA systematic study was made of the action on the plasma coagulation system of 20 Australian and Papuan Elapid and Hydrophiid snake venoms and compared with 4 Crotalid venoms and 1 Viper. The majority of Australian venoms were shown to be prothrombin activators with variable dependence on the presence of factor V phospholipid and calcium. None of these venoms had strong thrombin like activity in contrast to the Crotalid venoms which were powerfully thrombin like. The Crotalid venoms were also strongly fibrinolytic unlike the Elapid venoms which showed no or minimal evidence of fibrinolytic activity.Four Elapid venoms and 2 Crotalid venoms showed anticoagulant activity which contained neither antithrombin nor fibrinogenolytic activity and may act upon the prothrombin complex.

The Heparin-Glotar Surface; Mdde Of Action And Practical Application

1981 ◽  
Author(s):  
P Olsson ◽  
R Larsson ◽  
L-E Lins ◽  
E Nilsson
Keyword(s):  
Blood Vessels ◽  
Mode Of Action ◽  
Surface Coating ◽  
Anticoagulant Activity ◽  
Coagulation System ◽  
Practical Application ◽  
Plasma Coagulation ◽  
Similar Mode

A heparinized surface with non-thrombogenic characteristics was prepared by stabilization of an ionic heparinamine complex with glutardialdehyde. The process can be applied to a large variety of materials.The coating makes the surface platelet canpatible because np fibrinogen is adsorbed. The interaction of the surface with plasma coagulation system is based upon its ability to adsorb active coagulation enzymes (thrombin) and to promote inhibition of the adsorbed enzyme in the presence of circulating anti thrombin III. The sequence involving enzyme adsorbaticn and subsequent inhibition is regenerative. Investigations on blood vessels have revealed that the intact endotheliim exerts a similar mode of action with regard to inhibition of coagulation enzymes.When the heparin in the surface coating is substituted for glucosaminoglycans with less anticoagulant activity than heparin, the created surfaces is still platelet compatible and maintains the ability to adsorb enzyme, but loses the ability to generate inhibition of the adsorbed enzymes. Such surfaces are highly thrcmbogenic.The heparin surfaces have been tested experimentally for various applications. A heparin coated intravascular pO2 sensor was used for accurate measurements without recalibrations for several days. A non-heparinized electrode deteriorated within hours. Hemodialysis was performed on non-heparinized dogs using surface-heparinized hemodialysis set.

Thrombin-Like and Factor X-Activator Components of Bothrops Snake Venoms

1979 ◽  
Vol 41 (02) ◽  
pp. 314-328 ◽  
Author(s):  
Linda Nahas ◽  
Aura S Kamiguti ◽  
M Alice R Barros
Keyword(s):  
Comparative Study ◽  
Anticoagulant Activity ◽  
Factor V ◽  
Factor X ◽  
Serum Factor ◽  
Snake Venoms ◽  
Coagulant Activity ◽  
Prothrombin Activation

SummaryA comparative study on the coagulant activity of snake venoms was carried out in 26 Bothrops species, using specific clotting systems for the thrombin-like and the factor X- activator activities. With only two exceptions (B. erythromelas and B. castelnaudi) all venoms showed thrombin-like activity, since they were able to clot fibrinogen directly. The absence of thrombin-like action of B. erythromelas venom is due to a fibrinogenolytic effect. Five venoms (B. atrox asper, B. bilineatus bilineatus, B. cotiara, B. fonsecai and B. itapetiningae) were unable to produce a prothrombin activator when preincubated with serum, factor V, and phospholipid. None of the venoms seems to require factors VII, VIII, IX, XII and XIII for their complete coagulant action. Direct prothrombin activation was observed in most of the Bothrops venoms, alone or combined with thrombin-like and factor X-activator activities.An anticoagulant activity was exhibited by B. castelnaudi venom, probably due to an. anti- Xa action. This study points out that the coagulant activity of snake venoms varies within the same genus and must be characterized for each species. Thus, in Bothrops venoms the thrombin-like and factor X-activator components are not always associated, the coagulant effect may be related only to one of the components.

Dermatan Sulfate and LMW Heparin Enhance the Anticoagulant Action of Activated Protein C

1999 ◽  
Vol 82 (11) ◽  
pp. 1462-1468 ◽  
Author(s):  
José Fernández ◽  
Jari Petäjä ◽  
John Griffin
Keyword(s):  
Molecular Weight ◽  
Unfractionated Heparin ◽  
Protein C ◽  
Dermatan Sulfate ◽  
Anticoagulant Activity ◽  
Activated Protein C ◽  
Factor V ◽  
Factor Va ◽  
Anticoagulant Action

SummaryUnfractionated heparin potentiates the anticoagulant action of activated protein C (APC) through several mechanisms, including the recently described enhancement of proteolytic inactivation of factor V. Possible anticoagulant synergism between APC and physiologic glycosaminoglycans, pharmacologic low molecular weight heparins (LMWHs), and other heparin derivatives was studied. Dermatan sulfate showed potent APC-enhancing effect. Commercial LMWHs showed differing abilities to promote APC activity, and the molecular weight of LMWHs correlated with enhancement of APC activity. Degree of sulfation of the glycosaminoglycans influenced APC enhancement. However, because dextran sulfates did not potentiate APC action, the presence of sulfate groups per se on a polysaccharide is not sufficient for APC enhancement. As previously for unfractionated heparin, APC anticoagulant activity was enhanced by glycosaminoglycans when factor V but not factor Va was the substrate. Thus, dermatan sulfate and LMWHs exhibit APC enhancing activity in vitro that could be of physiologic and pharmacologic significance.

Cold Promoted Activation of Factor VII

1972 ◽  
Vol 28 (02) ◽  
pp. 155-168 ◽  
Author(s):  
H Gjønnæs
Keyword(s):  
Coagulation Factors ◽  
Oral Contraception ◽  
Factor Vii ◽  
Coagulation System ◽  
Plasma Coagulation ◽  
Main Effect

SummaryThe cold promoted shortening of the thrombotest-times occuring in the plasmas of the majority of women on oral contraception or in the last trimester of pregnancy when incubated overnight at 0°–4° was investigated.The short thrombotest-times were caused by activation of factor VII in a time consuming reaction. Activation was also revealed in the intrinsic coagulation system, but the changes in the activities of coagulation factors other than factor VII were small.Comparison was made between clot promoting effects of cooling and contact, and it was concluded that while contact apparently exerted its main effect in the intrinsic system, cooling predominately activated the extrinsic plasma coagulation system.The cold promoted activation of factor VII seemed to be brought about by an activator.

Inhibition of Fibrinolytic Activity In-Vivo by Dexamethasone Is Counterbalanced by an Inhibition of Platelet Aggregation

1992 ◽  
Vol 68 (01) ◽  
pp. 069-073 ◽  
Author(s):  
J J J van Giezen ◽  
J W C M Jansen
Keyword(s):  
Platelet Aggregation ◽  
Fibrinolytic Activity ◽  
Ex Vivo ◽  
Dose Range ◽  
Coagulation System ◽  
Loop Model ◽  
Prothrombotic State ◽  
Inhibition Of Platelet Aggregation ◽  
Pai 1

SummaryDexamethasone decreases the fibrinolytic activity in cultured medium of several cell types by an induction of PAI-1 synthesis. As a result of this enhanced PAI-1 synthesis a prothrombotic state is expected in patients treated with dexamethasone. However, such a prothrombotic state is not reported as a major adverse effect. We have studied the effects of dexamethasone (dose range: 0.1–3.0 mg/kg) on the fibrinolytic system of rats after a 5 day pretreatment period. It appeared that dexamethasone dose dependently decreased the fibrinolytic activity (a dose of 1 mg/kg showed a reduction of about 40%). This reduced fibrinolytic activity could be functionally translated into an increased thrombus size as measured with a venous thrombosis model: thrombus size was increased by 50% with 1 mg/kg dexamethasone. No effects could be measured on the coagulation system, but it appeared that ex-vivo measured platelet aggregation was dose dependently inhibited by dexamethasone treatment. This effect resulted in-vivo in prolonged obstruction times as measured with a modified aorta-loop model. These results indicate that the expected prothrombotic state due to a diminished fibrinolytic activity caused by dexamethasone is counterbalanced by an inhibition of platelet aggregation.

scholarly journals Progress in research on the role of fibrinogen in lung cancer

2020 ◽  
Vol 15 (1) ◽  
pp. 326-330
Author(s):  
Xing Liu ◽  
Bin Shi
Keyword(s):  
Lung Cancer ◽  
Coagulation Factor ◽  
Coagulation System ◽  
Plasma Coagulation ◽  
Hepatic Cells ◽  
Tumor Growth And Metastasis ◽  
Cancer Côlon ◽  
The Relationship ◽  
Multiple Interactions

AbstractLung cancer is one of the most prevalent malignancies worldwide. Local recurrence and distant metastasis remain the major causes of treatment failure. It has been recognized that the process of tumor growth and metastasis involves multiple interactions between tumor and host. Various biomarkers have been used for predicting tumor recurrence, metastasis, and prognosis in patients with lung cancer. However, these biomarkers are still controversial and require further validation. The relationship between malignancy and coagulation system disorders has been explored for more than a century. Fibrinogen is the most abundant plasma coagulation factor synthesized mainly by hepatic cells. Increased plasma fibrinogen levels were observed in various carcinomas such as gastric cancer, colon cancer, and pancreatic cancer. Recent studies have also investigated the role of fibrinogen in patients with lung cancer. This review aimed to address the role of fibrinogen in lung cancer.

scholarly journals Pharmacological Characterisation of Pseudocerastes and Eristicophis Viper Venoms Reveal Anticancer (Melanoma) Properties and a Potentially Novel Mode of Fibrinogenolysis

2021 ◽  
Vol 22 (13) ◽  
pp. 6896
Author(s):  
Bianca op den Brouw ◽  
Parviz Ghezellou ◽  
Nicholas R. Casewell ◽  
Syed Abid Ali ◽  
Behzad Fathinia ◽  
...  
Keyword(s):  
Anticancer Agents ◽  
Serine Proteases ◽  
Human Melanoma ◽  
Snake Venoms ◽  
Lead Compounds ◽  
Bioactive Properties ◽  
Fibrinogenolytic Activity ◽  
Pharmacological Potential ◽  
Hydrolysis Of ◽  
Viper Venoms

Venoms are a rich source of potential lead compounds for drug discovery, and descriptive studies of venom form the first phase of the biodiscovery process. In this study, we investigated the pharmacological potential of crude Pseudocerastes and Eristicophis snake venoms in haematological disorders and cancer treatment. We assessed their antithrombotic potential using fibrinogen thromboelastography, fibrinogen gels with and without protease inhibitors, and colourimetric fibrinolysis assays. These assays indicated that the anticoagulant properties of the venoms are likely induced by the hydrolysis of phospholipids and by selective fibrinogenolysis. Furthermore, while most fibrinogenolysis occurred by the direct activity of snake venom metalloproteases and serine proteases, modest evidence indicated that fibrinogenolytic activity may also be mediated by selective venom phospholipases and an inhibitory venom-derived serine protease. We also found that the Pseudocerastes venoms significantly reduced the viability of human melanoma (MM96L) cells by more than 80%, while it had almost no effect on the healthy neonatal foreskin fibroblasts (NFF) as determined by viability assays. The bioactive properties of these venoms suggest that they contain a number of toxins suitable for downstream pharmacological development as candidates for antithrombotic or anticancer agents.

S PROTEIN/VITRONECTIN NEUTRALIZES THE ANTICOAGULANT ACTIVITY OF GLYCOSAMINOGLYCANS IN THE INHIBITION OF THROMBIN BY HEPARIN COFACTOR II

1987 ◽  
Author(s):  
K T Preissner ◽  
P Sie
Keyword(s):  
Dermatan Sulfate ◽  
Enzyme Inhibitor ◽  
Anticoagulant Activity ◽  
Coagulation System ◽  
Binary Complex ◽  
Heparin Cofactor Ii ◽  
S Protein ◽  
Adhesive Protein ◽  
Inhibition Of Thrombin

The complement inhibitor S protein, which is identical to the adhesive protein vitronectin, functions as heparin-neutralizing factor by protecting thrombin against fast inactivation by antithrombin III. The interference of S protein with glycos-aminoglycan-catalyzed inhibition of thrombin by heparin cofactor II was investigated in a purified system. In the presence of 0.3 μg/ml heparin, or 0.5 μg/ml pentosan polyphosphate (SP 54), or 2 μg/ml dermatan sulfate, S protein induced a concentration-dependent reduction of the inhibition rate of thrombin by heparin cofactor II. This resulted in a decrease of the apparent pseudo-first order rate constants by about 17-fold (heparin), or about 7-fold (SP 54), but only by about 2-fold for dermatan sulfate at a physiological ratio of S protein to heparin cofactor II. Likewise, S protein significantly counteracted the anticoagulant activity of heparin and SP 54 bot not of dermatan sulfate when tested in an inhibition assay using various concentrations of glycosaminoglycans. For heparin, the activity of S protein at the point of 50% inhibition of thrombin was expressed in the range 0.06-0.6 μg/ml (0.01-0.1 U/ml) and for SP 54 in the range 0.3-2 pg/ml. Exposure of the glycos-aminoglycan-binding region of S protein by reduction and carb-oxymethylation of the protein even increased the neutralizing activity of S protein towards heparin and SP 54. S protein not only was found together with thrombin in a binary complex. S protein also became incorporated into a ternary complex with thrombin and heparin cofactor II as judged by crossed immunoelectrophoresis, regardless whether complex formation was initiated by heparin or dermatan sulfate. These findings underline the role of S protein as potent glycosaminoglycan-neutral-izing protein in plasma and as scavenger protein which may bind to enzyme-inhibitor complexes of the coagulation system.

The APC-independent anticoagulant activity of protein S in plasma is decreased by elevated prothrombin levels due to the prothrombin G20210A mutation

Blood ◽  
2003 ◽  
Vol 102 (5) ◽  
pp. 1686-1692 ◽  
Author(s):  
Rory R. Koenen ◽  
Guido Tans ◽  
René van Oerle ◽  
Karly Hamulyák ◽  
Jan Rosing ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Protein C ◽  
Anticoagulant Activity ◽  
Factor V Leiden ◽  
Protein S ◽  
Prothrombin G20210a ◽  
Healthy Population ◽  
Factor V ◽  
Thrombotic Risk ◽  
G20210a Mutation

AbstractProtein S exhibits anticoagulant activity independent of activated protein C (APC). An automated factor Xa–based one-stage clotting assay was developed that enables quantification of the APC-independent activity of protein S in plasma from the ratio of clotting times (protein S ratio [pSR]) determined in the absence and presence of neutralizing antibodies against protein S. The pSR was 1.62 ± 0.16 (mean ± SD) in a healthy population (n = 60), independent of plasma levels of factors V, VIII, IX, and X; protein C; and antithrombin, and not affected by the presence of factor V Leiden. The pSR strongly correlates with the plasma level of protein S and is modulated by the plasma prothrombin concentration. In a group of 16 heterozygous protein S–deficient patients, the observed mean pSR (1.31 ± 0.09) was significantly lower than the mean pSR of the healthy population, as was the pSR of plasma from carriers of the prothrombin G20210A mutation (1.47 ± 0.21; n = 46). We propose that the decreased APC-independent anticoagulant activity of protein S in plasma with elevated prothrombin levels may contribute to the thrombotic risk associated with the prothrombin G20210A mutation.

Abstract 43: Prothrombinase Assembled with Factor V Leiden is Resistant to Inhibition by Tissue Factor Pathway Inhibitor α Lowering the Procoagulant Threshold for Initiation of Coagulation

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Jeremy P Wood ◽  
Lisa M Baumann Kreuziger ◽  
Susan A Maroney ◽  
Rodney M Camire ◽  
Alan E Mast
Keyword(s):  
Tissue Factor ◽  
Thrombin Generation ◽  
Tissue Factor Pathway Inhibitor ◽  
Platelet Rich Plasma ◽  
Anticoagulant Activity ◽  
Factor V Leiden ◽  
Factor Xa ◽  
Factor V ◽  
Activation Threshold ◽  
Tissue Factor Pathway

Factor V (FV) assembles with factor Xa (FXa) into prothrombinase, the enzymatic complex that converts prothrombin to thrombin. Tissue factor pathway inhibitor α (TFPIα) inhibits prothrombinase by high affinity interactions with FXa-activated FV and the FXa active site, thereby blocking the initiation of coagulation. FV Leiden (FVL) is strongly linked to venous thrombosis through its resistance to degradation by activated protein C (aPC), which enhances the propagation of coagulation. FVL combined with a 50% reduction in TFPI causes severe thrombosis and perinatal lethality in mice, suggesting that FVL also promotes the initiation of coagulation. To examine this possibility, thrombin generation assays initiated with limiting FXa were performed with control or FVL plasma and platelet-rich plasma (PRP). The activation threshold for thrombin generation was 10 to 20 pM FXa in 10 control plasmas, but was 5 pM in 4 of 10 homozygous FVL plasmas. FVL PRP had a similar decrease in the activation threshold. The differences in activation threshold were totally normalized by an anti-TFPI antibody, while exogenous TFPIα and a FV-binding peptide that mimics TFPIα had reduced anticoagulant activity in FVL plasma, revealing that the procoagulant effects of FVL in these assays rely on TFPIα. Next, FVL plasmas were studied in fibrin clot formation assays, as they are sensitive to small amounts of thrombin. In reactions activated with 0.5 pM FXa, 1 of 8 control plasmas, compared to 7 of 8 homozygous FVL plasmas, clotted within 60 minutes, with differences again normalized by the anti-TFPI antibody. In prothrombinase activity assays using purified proteins, TFPIα was a 1.7-fold weaker inhibitor of prothrombinase assembled with FVL compared to FV. Thus, in addition to its aPC-mediated effect on the propagation of coagulation, FVL is resistant to TFPIα inhibition, exerting a procoagulant effect on coagulation initiation. This is evident in responses to small stimuli, where TFPIα blocks clotting in plasmas with FV but not FVL. The TFPIα-mediated modulation of the procoagulant threshold may explain the severe perinatal thrombosis in FVL mice with decreased TFPI and be clinically relevant in the clotting associated with oral contraceptives, which cause acquired TFPI deficiency.

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