Fibrin clot properties and fibrinolysis in patients with endocrine hypertension due to aldosterone or catecholamines excess

SummaryHaemorrhagic metalloproteinases from Bothrops jararaca and other venoms degrade vessel-wall and plasma proteins involved in platelet plug and fibrin clot formation. These enzymes also cause proteolytic digestion of fibrinogen which has been suggested to cause defective platelet function. Fibrinogen degradation by jararhagin, a metalloproteinase from B. jararaca, and the effect of jararhagin fibrinogenolysis on both platelet aggregation and fibrin clot formation were investigated. Jararhagin was found to cleave human fibrinogen in the C-terminal region of the Aα-chain giving rise to a 285-290 kDa fibrinogen molecule lacking the Aα-chain RGD 572-574 platelet-binding site. Platelet binding and aggregation of ADP-activated platelets is unaffected by this modification. This indicates that the lost site is not essential for platelet aggregation, and that the remaining platelet binding sites located in the N-terminal portion of Aα chains (RGD 95-97) and the C-terminal of γ chains (dodecapeptide 400-411) are unaffected by jararhagin-digestion of fibrinogen. Fibrin clot formation with thrombin of this remnant fibrinogen molecule was defective, with poor polymerization of fibrin monomers but normal release of FPA. The abnormal polymerization could be explained by the loss of one of the two complementary polymerization sites required for side-by-side association of fibrin protofibrils. Jararhagin-induced inhibition of platelet function, an important cause of haemorrhage in envenomed patients, is not caused by proteolysis of fibrinogen, as had been thought, and the mechanism remains to be elucidated.

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Fibrin Formation: The Role of the Fibrinogen-Fibrin Monomer Complex

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648007 ◽

1976 ◽

Vol 36 (01) ◽

pp. 037-048 ◽

Cited By ~ 49

Author(s):

Eric P. Brass ◽

Walter B. Forman ◽

Robert V. Edwards ◽

Olgierd Lindan

Keyword(s):

Particle Size ◽

Induction Period ◽

Fibrin Clot ◽

Clot Formation ◽

Appreciable Amount ◽

Buffer System ◽

Homeostatic Mechanism ◽

Fibrin Formation ◽

Fibrin Monomer

SummaryThe process of fibrin formation using highly purified fibrinogen and thrombin was studied using laser fluctuation spectroscopy, a method that rapidly determines particle size in a solution. Two periods in fibrin clot formation were noted: an induction period during which no fibrin polymerization occurred and a period of rapid increase in particle size. Direct measurement of fibrin monomer polymerization and fibrinopeptide release showed no evidence of an induction period. These observations were best explained by a kinetic model for fibrin clot formation incorporating a reversible fibrinogen-fibrin monomer complex. In this model, the complex serves as a buffer system during the earliest phase of fibrin formation. This prevents the accumulation of free polymerizable fibrin monomer until an appreciable amount of fibrinogen has reacted with thrombin, at which point the fibrin monomer level rises rapidly and polymerization proceeds. Clinically, the complex may be a homeostatic mechanism preventing pathological clotting during periods of elevated fibrinogen.

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Effects of Prostaglandins, Derivatives of Cyclic 3':5'-AMP, Theophylline, Cholinergic Agents and Colchicine on Clot Retraction in Dilute Platelet-Rich Plasma and Gel-Separated Platelet Test Systems

Thrombosis and Haemostasis ◽

10.1055/s-0038-1651477 ◽

1977 ◽

Vol 38 (02) ◽

pp. 0420-0428 ◽

Cited By ~ 1

Author(s):

J. L Moake ◽

P. L Cimo ◽

K Widmer ◽

D. M Peterson ◽

J. R Gum

Keyword(s):

Platelet Rich Plasma ◽

Inhibitory Effect ◽

Fibrin Clot ◽

Serotonin Release ◽

Dibutyryl Camp ◽

Clot Retraction ◽

Dilute Suspensions ◽

Cholinergic Agents ◽

Camp Levels ◽

Derivatives Of

SummaryIn dilute suspensions of platelet-rich plasma (PRP) or gel-separated platelets (GSP), dibutyryl-cAMP (DBcAMP) and monobutyryl-cAMP inhibited platelet-mediated fibrin clot retraction in concentrations of 2–3 × 10–6M, with complete inhibition at 1–3 × 10–4M. Prostaglandin E1 (PGE1), which inhibited fibrin clot retraction in concentrations greater than 1.5–3 × 10–8M, was a more effective inhibitor than either PGE2 or PGF2α. In the presence of theophylline (10–4M), concentrations of DBcAMP, PGE1 PGE2 and PGF2α necessary to inhibit fibrin clot retraction were reduced 50-fold for DBcAMP and 2.5 to 20-fold for the prostaglandins. In dilute PRP or GSP, inhibition of fibrin clot retraction does not result from inhibition of thrombin-induced platelet aggregation. Thus, compounds which increase platelet cAMP levels result in the inhibition of platelet-mediated fibrin clot retraction, and this inhibitory effect may be mediated, at least in part, through suppression of platelet contractility. Cyclic GMP, dibutyryl-cGMP and carbamylcholine-Cl (which stimulates guanylate cyclase) did not influence fibrin clot retraction, and did not prevent inhibition of fibrin clot retraction by DBcAMP and PGE?. Colchicine, in concentrations known to disrupt platelet microtubules (2.5 × 10–6M to 2.5 x 10–3M), had little inhibitory effect on either fibrin clot retraction or platelet (3H)-serotonin release.

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The Roles of α2-Antiplasmin and Plasminogen Activator Inhibitor 1 (PAI-1) in the Inhibition of Clot Lysis

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649570 ◽

1993 ◽

Vol 70 (02) ◽

pp. 301-306 ◽

Cited By ~ 51

Author(s):

Linda A Robbie ◽

Nuala A Booth ◽

Alison M Croll ◽

Bruce Bennett

Keyword(s):

Plasminogen Activator ◽

Plasminogen Activator Inhibitor ◽

Fibrin Clot ◽

Clot Lysis ◽

Plasminogen Activator Inhibitor 1 ◽

Dependent Inhibition ◽

Activator Inhibitor ◽

Pai 1

SummaryThe relative importance of the two major inhibitors of fibrinolysis, α2-antiplasmin (α2-AP) and plasminogen activator inhibitor (PAI-1), were investigated using a simple microtitre plate system to study fibrin clot lysis in vitro. Cross-linked fibrin clots contained plasminogen and tissue plasminogen activator (t-PA) at concentrations close to physiological. Purified α2-AP and PAI-1 caused dose-dependent inhibition. All the inhibition due to normal plasma, either platelet-rich or poor, was neutralised only by antibodies to α2-AP. Isolated platelets, at a final concentration similar to that in blood, 2.5 × 108/ml, markedly inhibited clot lysis. This inhibition was neutralised only by antibodies to PAI-1. At the normal circulating ratio of plasma to platelets, α2-AP was the dominant inhibitor. When the platelet:plasma ratio was raised some 20-fold, platelet PAI-1 provided a significant contribution. High local concentrations of PAI-1 do occur in thrombi in vivo, indicating a role for PAI-1, complementary to that of α2-AP, in such situations.

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The Preparation and Evaluation of a Standardized Fibrin Plate for the Assessment of Fibrinolytic Activity

Thrombosis and Haemostasis ◽

10.1055/s-0038-1654135 ◽

1970 ◽

Vol 23 (02) ◽

pp. 202-210 ◽

Cited By ~ 13

Author(s):

R Bishop ◽

H Ekert ◽

G Gilchrist ◽

E Shanbrom ◽

L Fekete

Keyword(s):

Test Specimen ◽

Fibrinolytic Activity ◽

Clinical Laboratory ◽

Fibrin Clot ◽

Fibrinolytic Enzyme ◽

Agarose Gel ◽

Fibrin Plate ◽

Percent Concentration ◽

Human Plasminogen ◽

Preparation And Evaluation

SummaryA new fibrin plate technic for evaluating components of the fibrinolytic system has been developed. It provides quick, accurate, and easily interpreted results for the fibrinolytic profile. The standardized human plasminogen-free fibrin plates can be produced in bulk and stored for prolonged periods of time. A test specimen placed in a well punched in the buffered agarose gel diffuses into the agar and lyses the fibrin clot, forming a clear reaction zone. The zone diameter is directly proportional to the log of the percent concentration of available fibrinolytic enzyme in the specimen. The plates may be used to quantitate total plasminogen, and estimate available plasmin and active plasmin. A good correlation between results obtained using these fibrin plates and caseinolytic methods was found. Performance and interpretation of tests of fibrinolysis done on these new fibrin plates indicate that it may be the most sensitive technic available for clinical laboratory work.

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Mechanism of Action of Synthetic Fibrinolytic Compounds

Thrombosis and Haemostasis ◽

10.1055/s-0038-1654259 ◽

1970 ◽

Vol 24 (03/04) ◽

pp. 495-506

Author(s):

W Baumgarten ◽

L. I Priester ◽

D. W Stiller ◽

A. E William Duncan

Keyword(s):

Mechanism Of Action ◽

Plasma Proteins ◽

Fibrinolytic Activity ◽

Fibrin Clot ◽

Plasma Clot ◽

Active Compounds ◽

Preformed Plasma ◽

Fibrinolytic Potential ◽

Fibrinolytic Compounds

SummaryThe mechanism of dissolution of a preformed plasma clot was explored.Our experiments showed clearly that the purified fibrin clot, made by extensive washing of a plasma clot, was resistant to lysis and that the fibrinolytic potential of the active fibrinolytic compounds was related to the presence of other plasma proteins in addition to fibrinogen.The activation of the fibrinolytic precursors was reversible inasmuch as removal of the fibrinolytic compounds negated the fibrinolytic activity of the protein-fibrinolytic compound mixture.Antifibrinolytic compounds which had been shown to interfer with fibrinolysis by streptokinase-activated plasminogen inhibited dissolution of the preformed plasma clot by fibrinolytically active compounds.The fibrinolytic potential of fibrinolytic compounds was additive; however, no apparent synergism was observed.The implication of these results to the mechanism of synthetic fibrinolysis was discussed.

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Anticoagulants Produced by Thrombin from Fibrin, the Effect on Blood Coagulation, Some Physical Characteristics

Thrombosis and Haemostasis ◽

10.1055/s-0038-1653670 ◽

1971 ◽

Vol 26 (02) ◽

pp. 211-223 ◽

Cited By ~ 2

Author(s):

Ch R. Muirhead ◽

D. C Triantaphyllopoulos

Keyword(s):

Blood Coagulation ◽

Gel Filtration ◽

Deae Cellulose ◽

Fibrin Clot ◽

Disc Electrophoresis ◽

Physical Characteristics ◽

Advanced Stage ◽

Kallikrein Inhibitor ◽

Shed Blood ◽

Complete Lysis

SummaryChromatographed thrombin in the presence of both 50 Kallikrein inhibitor units of Trasylol per ml and 0.1 M E-ACA solubilized fibrin and the products of lysis possessed anticoagulant properties. The peak of the antithrombic activity coincided with the time of complete lysis of the fibrin clot, plasmin lysed fibrin exhibited the peak of its antithrombic activity much earlier. The effect of thrombin lysed fibrin on the prothrombin consumption of shed blood was found to be inhibitory.The products of the digestion of fibrin by thrombin and by plasmin, isolated at an advanced stage of proteolysis were compared by gel filtration, disc electrophoresis and DEAE cellulose chromatography. Differences in physical characteristics of these fibrin breakdown products offer evidence that they were produced by two different enzymes.

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The Anticoagulant Effect of Heparinoid Org 10172 During Haemodialysis: An Objective Assessment

Thrombosis and Haemostasis ◽

10.1055/s-0038-1661535 ◽

1986 ◽

Vol 55 (02) ◽

pp. 271-275 ◽

Cited By ~ 22

Author(s):

Helen Ireland ◽

D A Lane ◽

Angela Flynn ◽

E Anastassiades ◽

J R Curtis

Keyword(s):

Renal Failure ◽

Bolus Dose ◽

Bolus Injection ◽

Objective Assessment ◽

Factor Xa ◽

Fibrin Clot ◽

Natural Origin ◽

Fibrin Formation ◽

Single Bolus Injection

SummaryThe heparinoid of natural origin Org 10172 has anti-factor Xa activity but minimal anti-thrombin activity, and little effect upon broad spectrum assays such as the KCCT in vitro. Its anticoagulant effects have been compared to those of commercial heparin in 7 patients undergoing haemodialysis for chronic renal failure. Commercial heparin was administered in a dose (5,000 iu bolus + 1,500 iu/hour continuous iv infusion) previously shown to inhibit fibrin formation during haemodialysis. This produced mean anti-factor Xa levels in plasma between 0.7-1.0 iu/ml and largely suppressed fibrin formation for 5 h dialysis measured as mean FPA levels in plasma. Administration of Org 10172 as a bolus of 1,350 anti-factor Xa u or 2,000-2,400 anti-factor Xa u produced plasma anti-factor Xa levels of less than 0.5 u/ml and allowed fibrin clot and FPA generation during dialysis. Org 10172 administered as a bolus dose of 4,000-4,800 anti-factor Xa u produced mean anti-factor Xa levels of greater than 0.5 u/ml, allowed dialysis of 6 patients for 5 h and appreciably suppressed FPA generation during dialysis, with little effect on the KCCT.It is concluded that the anti-factor Xa activity of Org 10172 may reflect its ability to inhibit fibrin during dialysis and that single bolus injection of Org 10172 may be a useful alternative method of achieving anticoagulation.

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Influence of Coagulation on the Activation of Plasminogen by Streptokinase and Urokinase

Thrombosis and Haemostasis ◽

10.1055/s-0038-1666939 ◽

1979 ◽

Vol 42 (03) ◽

pp. 901-908 ◽

Cited By ~ 25

Author(s):

Akikazu Takada ◽

Tetsumei Urano ◽

Yumiko Takada

Keyword(s):

Human Plasma ◽

Fibrin Clot ◽

Chromogenic Substrate ◽

Hydrolysis Of

SummaryHuman plasma was mixed with Ca++ or thrombin, and urokinase (UK) or streptokinase (SK) and a chromogenic substrate (S-2251: H-D-Val-Leu-Lys-pNA) specific to plasmin. The hydrolysis of S-2251 was higher when clot was formed by the addition of Ca++ or thrombin than in the absence of clot. The hydrolysis of S-2251 by euglobulin in the presence of UK was also higher when clot was formed, thus, inhibitors may not be related to the better activation of plasminogen, in the presence of fibrin clot. It may be suggested that plasminogen was better activated by activators (UK and SK) in the clot than in its absence.

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Endocrine hypertension: before and after treatment of the endocrinopathy

Endocrine Abstracts ◽

10.1530/endoabs.63.p49 ◽

2019 ◽

Author(s):

Marwa Khiari ◽

Ibtissem Ben Nacef ◽

Imene Rojbi ◽

Karima Khiari ◽

M Jerbi ◽

...

Keyword(s):

Endocrine Hypertension ◽

Before And After

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