[Plasminogen activators and thrombolytic therapy].

The mechanism of plasminogen activation by streptokinase, tissue and urokinase-type plasminogen activators (PAs) were reviewed. The regulatory role of fibrin in plasminogen activation involving its direct interaction with tissue-type PA and indirect interaction with streptokinase and urokinase-type PAs was demonstrated. Recent information on the development of new PAs is also displayed. The result of studies of PA mutant derivatives synthesized by recombinant DNA techniques are discussed. Date on chimeric (hybrid) forms of PAs and their chemically synthesized conjugates are presented. The trend in search for PAs is analysed. A new direction in the study of PAs for combined plasminogen activation and the further development of the methods of thrombolytic therapy was outlined.

[Thrombolysis: achievements, problems, prospects]. / Trombolizis: dostizheniia, Problemy, perspektivy.

Data on the mechanism of plasminogen activation by streptokinase, tissue and urokinase-type plasminogen activators (PAs) is reviewed. The regulatory role of fibrin in plasminogen activation involving its direct interaction with tissue-type PA and indirect interaction with streptokinase and urokinase-type PAs is demonstrated. Information on the current PAs use in thrombolytic therapy is also presented. The complications arising with administration of such thrombolytic agents are analyzed and the causes of complications are supposed. Recent information on the development of new PAs is also reviewed. The results of studies of PA mutant derivatives synthesized by recombinant DNA techniques as well as chimeric (hybrid) forms of PAs and their chemically synthesized conjugates are presented. The trend in search for PAs is analyzed. A new direction in the study of PAs for combined plasminogen activation and further development of the methods of thrombolytic therapy is outlined.

[Protein C system and thrombosis diseases]. / Sistema proteina C i trombozy.

The mechanism of protein C system functioning and role of its components in the regulation of the coagulation and the fibrinolysis was considered in the review. There are also new data about the anticoagulation, profibrinolysis and antiinflammatory functions of protein C system. Activated protein C is inhibited by the protein C inhibitor, alpha 1-antitripsin, and inhibitor of tissue activator plasminogen-1. Hereditary or acquired deficiency of protein C, protein S and thrombomodulin lead to thrombotic diseases. Injection of exogenous recombinant protein C or activated protein C into the blood increases the anticoagulant activity of the blood and produced the antithrombotic effect.

Factor IX of the blood coagulation system: a review.

Factor IX is a factor of the blood coagulation system. Its activation occurs on the surface of phospholipid membranes. It can be activated by the factor VIIa-TF (tissue factor)-Ca2+ complex via an extrinsic pathway and by factor XIa in the presence of Ca2+ via the intrinsic pathway of blood coagulation system activation. The activated factor IXa is a serine proteinase. The main function of the activated factor IXa in complex with factor VIIIa and phospholipids in presence of Ca2+ consists of the activation of factor X. Factor IX is synthesized in the liver and is subject to a number of posttranslational modifications including gamma-carboxylation, beta-hydroxylation, and glycosylation. It forms a subgroup of vitamin K-dependent plasma proteins including factors VII and X and protein C characterized by identical domain structures having high levels of homology. Factor IX consists of an NH2-terminal Gla domain, two epidermal growth factor (EGF)-like domains, and a C-terminal domain containing Ser in its active site. Factor IX deficiency in human plasma results in the disease known as hemophilia B.

[Method of determining factor IX activity]. / Metod opredeleniia aktivnosti faktora IX.

Modification of the method for factor IX activity determination was proposed. A mixture of chicken plasma and human plasma was used as factor IX-deficient substrate plasma. Moreover determinations were performed in the lack of kaolin-activator of factor XII. This allowed simplifying the assay performance. The described modification may be used to determine factor IX activity in its concentrates with the aim of diagnosis of haemophilia B and control of the disease treatment.

[Methods for determining the activity of factors VII, VIII, IX and X of the blood coagulation system]. / Metody opredeleniia aktivnosti faktorov VII, VIII, IX and X sistemy svertyvaniia krovi.

The existing methods for determination of activity of the VII, VIII, IX and X factors of the coagulation system have been analyzed. The comparative evaluation of their efficiency which depends on complexity, reprocibility, sensibility and test performance time is considered. The important role of these methods in scientific investigation for the diagnosis of haemophilia A, haemophilia D, factors VII and X deficiency for the purposes of therapy is emphasized.

[Comparative study of active site structure in bovine and Pacific salmon trypsins]. / Sravnitel'noe issledovanie struktury aktivnykh tsentrov tripsina byka i tikhookeanskikh lososevykh.

The kinetic investigation was carried out on the inhibition of hydrolysis of N, alpha-benzoyl-D, L-arginine-p-nitroanilide (BApNA) for bovine and salmon trypsin by phenylmethanesulphonyl fluoride (PMSF), N, alpha-tosyl-L-lysine chloromethyl ketone (N-TLCK), N, alpha-tosyl-L-phenylalanine chloromethyl ketone (N-TPCK). Kinetic parameters of inhibition (Ki, k2) by PMSF for salmon and bovine trypsin differ insignificantly. The k2/Ki value of N-TPCK for salmon trypsin is 10 times more than of bovine trypsin. Kinetic parameters of inhibition by N-TLCK had the less difference. The Ki value of this inhibitor for salmon trypsin is 5 times less than that of bovine trypsin and k2 value is 1.7 times less.

[The complement system]. / Sistema komplementa.

The complement system represents a multitude of activating factors, associated with the cellular membrane and providing for cell lysis. The system is composed of 21 serum proteins and 8 receptors and may be found in cells of various types. The major function of the system consists in its activation which entails a cascade of events terminated by cell lysis. Two complement system activation mechanisms are generally distinguished, one of which is classical and one is alternative. These two mechanisms converge after the activation of the third component (C3) or as a result of interaction between the terminal components (C5, C6, C7, C8 and C9) of the complement cascade. The complement system is linked with the fibrinolytic, blood coagulating and kinin systems.

[Comparative kinetic studies of the primary specificity of bovine and salmon trypsin]. / Sravnitel'nye kineticheskie issledovaniia pervichnoi spetsifichnosi tripsina byka i tripsina lososevykh.

A comparative kinetic analysis of Pacific salmon and bovine trypsins revealed that the former hydrolyzes p-nitroanilide-N,L-benzoyl-D,L-arginine (BApNA) with a far greater efficiency in comparison with bovine trypsin due to the decrease in Km. The inhibition constants for the BApNA hydrolysis by bovine and salmon trypsin with glycine, beta-alanine, L-lysine, L-arginine and benzamidine were determined. With an increase in the length of the hydrocarbon chain in the inhibitor molecule (i.e., in the order of glycine-beta-alanine-L-lysine) the inhibiting effect increased both with salmon and bovine trypsins. The Ki values for benzamidine and L-arginine appeared to be by one order of magnitude higher with salmon trypsin than with bovine trypsin. L-arginine was a much more effective inhibitor compared to L-lysine when both salmon and bovine trypsins were used.

[The effect of kringles K1-3, K4 and K5 on lysis of fibrin clots caused by the activation of Glu- and Lys-plasminogen by a tissue activator]. / Vliianie kringlov K1-3, K4 and K5 na lizis fibrinovogo sgustka, vyzvannyi aktivatsiei Glu- i Lys-plazminogena tkanevym aktivatorom.

Kringles K1-3, K4 and K5 are studied for their effect on tissue plasminogen activator-induced fibrin clot lysis in the presence of Glu- and Lys-plasminogen. It is established that kringles K4 and K5 inhibit fibrinolysis of Glu-plasminogen, and K1-3--that of Lys-plasminogen. The role of plasminogen molecule kringles in the plasminogen interaction with fibrin polymer is discussed.

[Kinetic characteristics of the activation of various structural forms of plasminogen by tissue activator in the presence of fibrin]. / Kineticheskaia kharakteristika aktivatsii razlichnykh strukturnykh form plazminogena tkanevym aktivatorom v prisutstvii fibrina.

It was shown that activation of two native plasminogen and miniplasminogen forms by the tissue activator in the presence of fibrin obeys the Michaelis-Menten kinetics. The kinetic parameters of activation of both plasminogen native forms differ insignificantly. For miniplasminogen whose molecule contains no lysine-binding sites, a marked decrease of activation power was observed. The Km value of activator for miniplasminogen is 10 times that of plasminogen form I and 20 times that of plasminogen form II. The kcat/Km value of activator for miniplasminogen is 7 times less than that of plasminogen form I and by one order of magnitude more than that of plasminogen form II. These results testify to the importance of lysine-binding sites in the native plasminogen molecule during the activation of fibrinolysis by the major physiological activator.

Kinetic characteristics of fibrinogen and fibrin hydrolysis by plasmin 1 and 2 and miniplasmin.

Fibrinogen and fibrin hydrolysis by native plasmin 1 and 2 and by miniplasmin was studied. The degree of hydrolysis was estimated by the number of amino groups determined with trinitrobenzene sulphonic acid. The process was shown to obey Michaelis-Menten kinetics. Kinetic parameters of fibrinogen and fibrin hydrolysis by plasmin forms 1 and 2 were identical (KM = 6.5 X 10(-6) M, kcat = 7.1 sec-1) while for hydrolysis by miniplasmin KM = 20.0 X 10(-6) M, kcat = 3.58 sec-1. Thus, it was demonstrated that enzymatic properties of plasmin are to some extent dependent on the presence of lysine-binding sites. However, this appears not to have a decisive effect on fibrinolytic process.

[Comparative evaluation of fibrinogen and fibrin hydrolysis with plasmin]. / Sravnitel'noe izuchenie gidroliza fibrinogena i fibrina plazminom.

A high-sensitive method is developed for determining the degree of plasmin-catalyzed fibrinogen hydrolysis by the released amino groups stained with trinitrobenzene sulphoacid. The method permits determining 0.02-0.08 casein units of plasmin. The method made it possible to establish that after streptokinase activation plasmin hydrolyzes equally fibrinogen and fibrin in solution and as gel. When a tissue activator is used, fibrin intensifies significantly the plasminogen activation. Inhibition of plasmin by an inhibitor produced from soya is considerably slowed down in fibrin gel.

[Micromethod for plasminogen determination]. / Mikrometod opredeleniia plazminogena.

Conditions are developed for determining potential activity of plasminogen in amine groups formed in casein hydrolysis. Two variants of determination are suggested: by means of a ninhydrin reagent and trinitrobenzene sulphoacid. The method permits determining 0.02-0.1 of plasmin casein units (cas. units); it is 20 times as sensitive as the known caseinolytic method based on determination of the degree of tyrosine absorption.