Differentiation between Plasminogen Activators by Means of Epsilon- Aminocaproic Acid

1972 ◽  
Vol 27 (01) ◽  
pp. 077-087 ◽  
Author(s):  
P Kok ◽  
T Astrup
Keyword(s):  
Plasminogen Activator ◽  
Human Urine ◽  
Aminocaproic Acid ◽  
Plasminogen Activators ◽  
Uterine Tissue ◽  
Biphasic Pattern ◽  
Fibrin Plate ◽  
Epsilon Aminocaproic Acid ◽  
Millimolar Concentration

SummaryThe differentiation between plasminogen activators from tissue and urine by means of the patterns of inhibition produced by epsilon-aminocaproic acid (EACA) in fibrin plate assays was investigated. Different inhibition patterns reflected genuine differences between two types of activators. The method allows the differentiation between two types of activators in weakly fibrinolytic and impure activator solutions.A biphasic pattern of inhibition by EACA was observed with human urine as well as with the purified urokinase preparations. The degree of enhancement of fibrinolysis observed in the millimolar concentration range of EACA fluctuated with the fibrin substrate and was, in part, related to its plasminogen content. Increasing concentrations of EACA produced a uniformly increasing inhibition of preparations of tissue activator obtained in various degrees of purity from porcine ovary and heart. Plasmin was uniformly inhibited by EACA. Inhibition of plasmin required about 100 times higher concentrations of EACA than inhibition of tissue activator-induced fibrinolysis. EACA produced a slightly biphasic pattern of inhibition with plasminogen activator from human uterine tissue.

Separation of Plasminogen Activators from Human Uterine Tissue and a Comparison with Activators from Human Urine and Porcine Tissue

1979 ◽  
Vol 41 (04) ◽  
pp. 718-733 ◽  
Author(s):  
Preben Kok
Keyword(s):  
Plasminogen Activator ◽  
Human Urine ◽  
Gel Filtration ◽  
Ammonium Thiocyanate ◽  
Plasminogen Activators ◽  
Particle Sizes ◽  
Uterine Tissue ◽  
Porcine Tissue ◽  
Major Activity ◽  
Proliferative Phase

SummaryThree types of plasminogen activator could be distinguished in extracts from human uterine tissue. The activators differed in thermostability or in mode of inhibition by EACA.All the extracts contained stable as well as labile activators. The saline extracts were uniformly inhibited by increasing concentrations of EACA. Extracts made with 2 M ammonium thiocyanate were either uniformly inhibited by EACA or showed deflections indicating contamination with an activator, which was inhibited in a biphasic manner. It was possible to distinguish between: (1) An activator, abundantly present in the tissue, which was uniformly inhibited and stable. (2) Another uniformly inhibited activator, which was labile. (3) An activator, inhibited in a biphasic manner, similar to urokinase, which was present in varying amounts in uteri with the endometrium in the proliferative phase.Gel filtration of the uterine extracts showed two major activity peaks corresponding to particle sizes of 60,000 dalton and about 10,000 dalton.Antiserum to purified plasminogen activator, prepared from porcine ovaries, inhibited the activity of the human uterine extracts, but not the activities of human urokinase or urine. Urokinase antiserum in a concentration completely inhibiting human urine or urokinase, inhibited only 10% or less of the activities of human uterine extracts.

Interfering Factors in the Assay of Plasminogen Activators by the Fibrin Plate Method

1979 ◽  
Vol 41 (03) ◽  
pp. 590-600 ◽  
Author(s):  
G Wijngaards
Keyword(s):  
Special Reference ◽  
Plasminogen Activator ◽  
Inhibitory Action ◽  
Human Lung ◽  
Plasminogen Activators ◽  
Uterine Tissue ◽  
Plate Method ◽  
Tissue Extracts ◽  
Fibrin Plate ◽  
Tissue Plasminogen

SummaryThe assay of plasminogen activator activities on fibrin plates was re-evaluated with special reference to fibrinolysis inhibitors present in samples and in fibrin plates. The nature, action and stability of inhibiting material were studied in tissues with considerable differences in activator and inhibitor contents! human lung, liver and placenta. Extracts were tested for inhibitory capacity against purified human uterine tissue plasminogen activator, urokinase and plasmin on fibrin plates prepared from different grades of fibrinogens and fibrin.The tissue extracts inhibited fibrinolysis on fibrin plates to varying degrees, dependent on the sample medium, the type of fibrin plate and the kind of plasminogen activator. The influence of inhibitors in the sample and in the fibrin plate was partly abolished by the presence of 2 M KSCN in the sample. The procedure for preparing the samples as described by Astrup and Albrechtsen did not completely eliminate the inhibitory action against the added plasminogen activators.Comparison of urokinase inhibition with tissue activator inhibition by the tissue extracts as to the degree of denaturation in the Astrup and Albrechtsen procedure showed that they have much in common. Nevertheless, some differences were found which indicated the possible existence of separate urokinase and tissue activator inhibitors or of different inhibition mechanisms for these plasminogen activators.

Reversible and Irreversible Alterations of Human Plasminogen Indicated by Changes in Susceptibility to Plasminogen Activators and in Response to ∈-Aminocaproic Acid

1974 ◽  
Vol 32 (02/03) ◽  
pp. 325-340 ◽  
Author(s):  
Sixtus Thorsen ◽  
Preben Kok ◽  
Tage Astrup
Keyword(s):  
Ionic Strength ◽  
Aminocaproic Acid ◽  
Plasminogen Activators ◽  
Plasminogen Activation ◽  
Porcine Tissue ◽  
Biphasic Pattern ◽  
Tissue Plasminogen ◽  
Human Plasminogen ◽  
Uniform Manner ◽  
Low Ionic Strength

SummaryIncreasing concentrations of EACA produce a biphasic pattern of inhibition and enhancement of urokinase-induced lysis of bovine fibrin containing bovine plasminogen, while the inhibition of fibrinolysis induced by a porcine tissue plasminogen activator increases uniformly. The biphasic EACA pattern is also observed with human plasminogen in fibrinolytic and caseinolytic assays of urokinase. The biphasic EACA pattern produced with urokinase is related to the presence of a genuine form of plasminogen. The enhancement phase is caused by an increased rate of plasminogen activation in the presence of EACA. A brief treatment of genuine plasminogen with acid at ionic strength 0.15 results in an enhanced susceptibility to plasminogen activators and in a partial abolishment of the biphasic response. These acid-induced alterations of plasminogen seem to be reversed by acid dialysis at low ionic strength. Other preparations of plasminogen with enhanced susceptibility to activators have lost the ability to produce a biphasic pattern of inhibition and enhancement of urokinase-induced plasminogen activation in the presence of EACA and this ability does not return after acid dialysis at low ionic strength. EACA inhibits all plasmin preparations, whether prepared from genuine or altered forms of plasminogen, in the same uniform manner.Our results show that different forms of plasminogen can be identified by differences in the susceptibilities to activators, by their response to EACA, and by the reversibility or irreversibility of the alterations.

Monitoring antifibrinolytic therapy in subarachnoid hemorrhage

1973 ◽  
Vol 38 (3) ◽  
pp. 339-344 ◽  
Author(s):  
Robert R. Smith ◽  
John J. Upchurch
Keyword(s):  
Cerebrospinal Fluid ◽  
Subarachnoid Hemorrhage ◽  
Aminocaproic Acid ◽  
Antifibrinolytic Agents ◽  
Duration Of Action ◽  
Content Type ◽  
The Past ◽  
Fibrin Plate ◽  
Epsilon Aminocaproic Acid ◽  
Ruptured Intracranial Aneurysms

✓ A modification of the fibrin plate method was developed to measure fibrinolysis in patients with subarachnoid hemorrhage and those receiving antifibrinolytic agents. During the past 2 years, 21 patients with ruptured intracranial aneurysms received epsilon aminocaproic acid. Plasma and cerebrospinal fluid were monitored in 15 of these patients. Dosage factors, duration of action, and complications of therapy are presented. Fibrinolysis in normal plasma and cerebrospinal fluid is also discussed.

scholarly journals Binding of fibrin fragments to one-chain and two-chain tissue-type plasminogen activator

Blood ◽  
1992 ◽  
Vol 79 (9) ◽  
pp. 2313-2321 ◽  
Author(s):  
AA Hasan ◽  
WS Chang ◽  
AZ Budzynski
Keyword(s):  
Plasminogen Activator ◽  
Binding Sites ◽  
Solid Phase ◽  
Aminocaproic Acid ◽  
Tissue Type ◽  
Plasminogen Activation ◽  
Tissue Type Plasminogen Activator ◽  
Microtiter Plates ◽  
Type Plasminogen Activator ◽  
Epsilon Aminocaproic Acid

To explore whether fibrin fragments have binding affinity for the tissue-type plasminogen activator (t-PA) molecule, the interactions were studied of (DD)E complex and fragments DD, E1, and E3 with one- chain and two-chain t-PA. For this purpose, a solid-phase binding assay was developed using microtiter plates with nitrocellulose filters. It was found that (DD)E complex and fragments DD and E3 retained the t-PA binding function of the parent fibrin molecule, thus demonstrating that t-PA binds to both the D and E domains of fibrin. Unexpectedly, fragment E1 did not bind t-PA. Fibrin fragments had different binding properties for one-chain and two-chain t-PA. (DD)E complex had the highest and fragment E3 the lowest affinity for one-chain t-PA, both binding curves being consistent with one class of binding sites. However, binding of the fragments with two-chain t-PA was distinguished by more than one class of binding sites, with fragment E3 having the highest affinity for this form of the activator. epsilon-Aminocaproic acid, even at 50 mmol/L concentration, had only minimal effect on binding of (DD)E complex or fragment DD to either one-chain or two- chain t-PA. The potentiating effect of fibrin fragments on plasminogen activation by t-PA was measured by a chromogenic substrate assay. Fragment DD was the most effective stimulator of plasminogen activation by t-PA. In conclusion, (DD)E complex and fragment DD retained most of the regulatory functions of fibrin, which included t-PA binding and t- PA-mediated acceleration of plasminogen activation to plasmin.

Fibrinolytic Activity in Man During Surgery

1962 ◽  
Vol 07 (03) ◽  
pp. 391-403 ◽  
Author(s):  
Lennart Andersson ◽  
Inga Marie Nilsson ◽  
Bertil Olow
Keyword(s):  
Blood Loss ◽  
Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Aminocaproic Acid ◽  
Coagulation Disorder ◽  
Normal Reaction ◽  
Plate Method ◽  
Fibrin Plate ◽  
Actual Operation ◽  
Induction Of Anaesthesia

Summary165 patients undergoing various operations were studied for any variation in the fibrinolytic activity of the blood, as measured by a modified fibrin plate method.The fibrinolytic activity was found to increase somewhat already after induction of anaesthesia, and almost always slightly to moderately during the actual operation.This activity is believed to be due to an increase of the plasminogen activator in the blood, since it can be inhibited by administration of ε-aminocaproic acid. It is presumably a normal reaction and, unless extreme or combined with some coagulation disorder, it probably has but little influence on blood loss at operation.

scholarly journals Binding of fibrin fragments to one-chain and two-chain tissue-type plasminogen activator

Blood ◽  
1992 ◽  
Vol 79 (9) ◽  
pp. 2313-2321 ◽  
Author(s):  
AA Hasan ◽  
WS Chang ◽  
AZ Budzynski
Keyword(s):  
Plasminogen Activator ◽  
Binding Sites ◽  
Solid Phase ◽  
Aminocaproic Acid ◽  
Tissue Type ◽  
Plasminogen Activation ◽  
Tissue Type Plasminogen Activator ◽  
Microtiter Plates ◽  
Type Plasminogen Activator ◽  
Epsilon Aminocaproic Acid

Abstract To explore whether fibrin fragments have binding affinity for the tissue-type plasminogen activator (t-PA) molecule, the interactions were studied of (DD)E complex and fragments DD, E1, and E3 with one- chain and two-chain t-PA. For this purpose, a solid-phase binding assay was developed using microtiter plates with nitrocellulose filters. It was found that (DD)E complex and fragments DD and E3 retained the t-PA binding function of the parent fibrin molecule, thus demonstrating that t-PA binds to both the D and E domains of fibrin. Unexpectedly, fragment E1 did not bind t-PA. Fibrin fragments had different binding properties for one-chain and two-chain t-PA. (DD)E complex had the highest and fragment E3 the lowest affinity for one-chain t-PA, both binding curves being consistent with one class of binding sites. However, binding of the fragments with two-chain t-PA was distinguished by more than one class of binding sites, with fragment E3 having the highest affinity for this form of the activator. epsilon-Aminocaproic acid, even at 50 mmol/L concentration, had only minimal effect on binding of (DD)E complex or fragment DD to either one-chain or two- chain t-PA. The potentiating effect of fibrin fragments on plasminogen activation by t-PA was measured by a chromogenic substrate assay. Fragment DD was the most effective stimulator of plasminogen activation by t-PA. In conclusion, (DD)E complex and fragment DD retained most of the regulatory functions of fibrin, which included t-PA binding and t- PA-mediated acceleration of plasminogen activation to plasmin.

Aminocaproic acid in haemophilia and in menorrhagia

1967 ◽  
Vol 5 (16) ◽  
pp. 63-64
Keyword(s):  
Urinary Tract ◽  
Factor Viii ◽  
Aminocaproic Acid ◽  
Plasminogen Activators ◽  
Dental Extraction ◽  
Antifibrinolytic Agent ◽  
Epsilon Aminocaproic Acid ◽  
Coagulation And Fibrinolysis

Normal haemostasis and healing probably depend on the maintenance of a balance between coagulation and fibrinolysis. If in a wound the fibrin plug is improperly formed because of deficient clotting, any measure to prevent its dissolution may discourage bleeding and promote healing. The synthetic antifibrinolytic agent epsilon-aminocaproic acid (EACA; Epsikapron - Kabi) has therefore been given to patients with haemophilia either alone or in conjunction with antihaemophilic globulin (AHG; Factor VIII). Theoretically the drug should help in bleeding from the urinary tract and after dental extraction because it inhibits plasminogen activators present in urine and saliva.

scholarly journals Clot penetration and fibrin binding of amediplase, a chimeric plasminogen activator (K2tu-PA)

2004 ◽  
Vol 91 (01) ◽  
pp. 52-60 ◽  
Author(s):  
Marrie Barrett-Bergshoeff ◽  
A. F. H. Jie ◽  
Marco Criscuoli ◽  
Dmitri Sakharov ◽  
Dingeman Rijken
Keyword(s):  
Plasminogen Activator ◽  
Aminocaproic Acid ◽  
Fibrin Clot ◽  
Clot Lysis ◽  
Plasma System ◽  
Plasma Clot ◽  
Lysis Activity ◽  
Epsilon Aminocaproic Acid ◽  
Kringle 2

SummaryAmediplase (K2tu-PA) is a hybrid plasminogen activator, consisting of the kringle 2 domain of alteplase and the protease domain of urokinase. The objective of this study was to determine the in vitro clot penetration of amediplase in relation to its fibrin binding and to compare the properties with those of alteplase.The clot lysis activity of amediplase in internal clot lysis models (both purified system and plasma system) was about 10 times less than that of alteplase. The clot lysis activity of amediplase in an external clot lysis model (plasma system) was similar to that of alteplase at therapeutic concentrations around 1 µg/ml. The fibrin-clot binding properties of amediplase and alteplase were studied in a purified system as well as in a plasma system. In both systems amediplase bound to fibrin although to a significantly lower extent than alteplase. The binding of amediplase or alteplase did not increase during plasmin-mediated degradation of fibrin. The binding of amediplase was fully inhibited by epsilon-aminocaproic acid, indicating that the observed binding was specific and occurred via the lysine binding site in the kringle of amediplase. Clot penetration was studied during pressure-driven fluid permeation using syringes containing plasma clots. Amediplase was able to enter the clot without significant hindrance, while alteplase was concentrated on the top of the plasma clot and hardly entered into the inner parts of the clot. Diffusion-driven clot penetration was studied during clot lysis using confocal microscopy. Alteplase was detected on or close to the clot surface, while two-chain urokinase, which has no affinity to fibrin, was also detected deep inside the clot. Amediplase showed a penetration behaviour, which was distinct from that of alteplase and similar to that of two-chain urokinase.We concluded that the fibrin binding of amediplase is moderate and does not hinder clot penetration under permeationdriven or diffusion-driven transport conditions. Enhanced clot penetration, especially in large clots, could allow a more efficient lysis during thrombolytic therapy.

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