Spontaneous pregnancy during ulipristal acetate treatment of giant uterine leiomyoma.

WHAT IS KNOWN AND OBJECTIVE: Ulipristal acetate, a progesterone receptor modulator, pharmacologically inhibits endometrial proliferation and thereby prevents pregnancy. It is primarily used as emergency contraception, but also for the treatment of fibroids in women of reproductive age. There have been no published cases of pregnancy, while on therapy with ulipristal acetate. CASE DESCRIPTION: In this article, we present a case report of spontaneous pregnancy during ulipristal acetate therapy. WHAT IS NEW AND CONCLUSION: To our knowledge, this is the first patient with spontaneous conception, while on ulipristal acetate treatment. There were no drug-related complications, and the pregnancy resulted in the delivery of a healthy baby.

Autoantibodies to plasminogen and their role in tumor diseases.

Plasma level of IgG autoantibodies to plasminogen was measured by ELISA in patients with benign prostatic hyperplasia (n=25), prostatic cancer (n=17), lung cancer (n=15), and healthy volunteers (n=44). High levels of IgG to plasminogen were found in 2 (12%) of 17 healthy women, in 1 (3.6%) of 27 specimens in a healthy man, in 17 (68%) of 25 specimens in prostatic cancer, in 10 (59%) of 17 specimens in lung cancer, and in 5 (30%) of 15 specimens in benign prostatic hyperplasia. Comparison of plasma levels of anti-plasminogen IgG by affinity chromatography showed 3-fold higher levels in patients with prostatic cancer vs. healthy men.

[Streptokinase and Staphylokinase: Differences in the Kinetics and Mechanism of Their Interaction with Plasminogen, Inhibitors and Fibrin].

Comparative in vitro study of the kinetics of various reactions involved in the process of thrombolysis initiated by streptokinase (SK) and staphylokinase (STA) was carried out. It was shown that at the interaction of an equimolar ratio of plasminogen (Pg) with SK or STA the rate of formation and the specific esterase activity of the complex plasmin (Pm) · SK are higher than those of the complex Pm · STA. The catalytic efficiency (kcat/Km) of hydrolysis of the chromogenic plasmin substrates by Pm · SK complex was 2 times higher than by Pm · STA complex. In the absence of fibrin catalytic efficiency (kPg/K(Pg)) of activation of Glu-plasminogen and Lys-plasminogen glycoform II by Pm · SK complex was higher than by Pm · STA complex, but the pres- ence of fibrin increased kPg/K(Pg)) activation of both plasminogens by Pm · STA complex significantly stronger than by Pm · SK complex due to the decrease in K(Pg)). In contrast to STA (15.5 kDa), SK molecule (47 kDa) creates significant steric hindrances for the interaction of plasmin in Pm · SK complex with protein inhibi- tors. In addition, SK caused greater fibrinogen degradation than STA. It is shown that Pm · SK and Pm · STA complexes lyse fibrin clots in buffer with similar rates, while the rate of lysis of plasma clots, immersed in plas- ma, by Pm · STA complex are significantly higher than those by Pm · SK complex. It was revealed that the species specificity of STA and S K is determined mainly by the rate of formation and the efficiency of Pm · SK and Pm · STA complexes in the activation of autologous plasminogen. The lysis efficiency of plasma clots of mammals fell in the series: human > dog > rabbit for SK and the dog > human > rabbit for STA. The results show that in the purified system SK is a more effective activator of plasminogen than STA. In the system con- taining fibrin and α2-AP, the activator and fibrinolytic activities of STA are higher than those of SK, due to the increased stability in plasma and fibrin specificity of STA, the fast reaction of the complex Pm · STA with α2AP and the ability of the STA to recyclization in the presence of α2AP.

[Polymorphism of the plasminogen activator inhibitor type 1 gene, plasminogen level and thrombosis in patients with antiphospholipid syndrome].

The frequency of venous and arterial thromboses and plasminogen level were investigated in 78 patients with antiphospholipid syndrome (APS), 35 of whom with systemic lupus erythematosus (SLE+APS) and 43 - with primary APS (PAPS). The levels and genotype of plasminogen activator inhibitor type 1 (PAI-1) were determined in 45 patients with APS, of whom 21 patients with SLE + APS and 24 patients with PAPS. A control group included 10 healthy individuals without autoimmune disease signs and thromboses on period of investigation and in past history. It was shown for the first time that for one third of 67 patients with APS and thromboses high positive levels of antiphospholipid antibodies (aPL) are associated with low plasminogen levels. The levels of PAI-1 antigen measured by ELIZA method, which detects active, latent and bound with plasminogen activator PAI-1, were opposed with frequency of thromboses in APS patients. Correlation between the high and increased levels of PAI-1 and high positive aPL levels was found for one third of 43 patients with APS and thrombosis. One of the possible mechanisms of this interconnection was considered. It was shown that arterial and, to a more extent, venous thromboses are associated with the 4G/5G polymorphism of PAI-1 gene and high plasma level of the inhibitor in 79% of APS patients. At the presence of the 4G allele patients with SLE+APS had higher PAI-1 levels than patients with PAPS. The obtained results show that measuring the levels of plasminogen and PAI-1 as well as the 4G/5G polymorphism of PAI-1 gene which is associated with thromboses may have the practical significance for identification of high risk of thrombosis in APS patients.

[Covalent stretokinase-polyethylene glycol conjugates with increased stability and decreased side effects].

By variation of incubation time of streptokinase (SK) with activated polyethylene glycol (M 2 and 5 kDa, PEG2 and PEG5) it was obtained covalent SK-PEG2 and SK-PEG5 conjugates with different modification degrees of amino groups of protein and their properties were studied in vitro as compared with free SK. It was shown, that maximal stable and retaining 80% fibrinolytic activity SK-PEG2 and SK-PEG5 conjugates are formed when the modification degrees of amino groups of protein are 54 and 52%, respectively. At interaction of the given conjugates with equimolar plasminogen concentration it were formed the plasmin (Pm)·SK-PEG2 and Pm·SK-PEG5 activator complexes, the maximal amidase activity of which is equal to activity of unmodified Pm·SK complex. It was found, that the catalytic efficiency of plasminogen activation (kPg/KPg) by Pm·SK-PEG2 complex is some higher (2.84 min(-1) µM(-1)) and by Pm·SK-PEG5 complex is lower (1.17 min(-1) µM(-1)), than that by unmodified Pm·SK complex (2.1 min(-1) µM(-1)). Investigation of lysis kinetics of human plasma clots and depletion of plasminogen and fibrinogen in plasma under the action of free SK and SK-PEG2 and SK-PEG5 conjugates showed, that the latter's have high thrombolytic activity (89 and 72%, respectively) and cause 3.5-4 fold lower side effects, than free SK. Obtained by us SK-PEG2 and SK-PEG5 conjugates with increased stability and decreased side effects may be used in the therapy of thrombotic disorders.

[Fibrinolysis components and angiogenesis regulation by example of burn-induced corneal neovascularization in rabbits].

Increased plasminogen level in tear fluid was found within 28 days and increased plasmin activity in 1-3 and 21 days after alkali burn of cornea, this is the time of cornel ulcers development. Increased plasminogen level and plasmin activity in cornea, conjunctiva and intraocular fluid was found in three days after trauma. Subconjunctival injections of angiostatin K1-4,5 (a product of plasminogen metabolism) during 3 weeks resulted in significant suppression of corneal neovascularization within 14 days and of active branching of the vessels in the following. The use of angiostatin reduced depth and area of corneal ulcers. Obtained data shows the promising potential of development of medications based on angiostatin K1-4,5 for suppression of corneal neovascularization and for treatment of diseases associated with corneal ulceration.

[Mechanism of inhibitory effect of angiostatin on plasminogen activation by its physiologic activators].

The influence of angiostatin K1-4.5--a fragment of the heavy chain of plasmin and a powerful inhibitor of angiogenesis--on kinetic parameters (k(Pg) and K(Pg)) of human Glu-plasminogen activation under the action of urokinase (uPA) not having affinity for fibrin and fibrin-specific tissue plasminogen activator (tPA) was investigated. Angiostatin does not affect the k(Pg) value, but increases the value K(Pg) urokinase plasminogen activation. A decrease in the k(Pg) value and an increase in the K(Pg) value were found for fibrin-stimulated plasminogen activation by tPA with increasing concentrations of angiostatin. The obtained results show that angiostatin is competitive inhibitor of the uPA activator activity, while it inhibits the activator activity of tPA by mixed type. Such an influence ofangiostatin on the kinetic constants ofthe urokinase plasminogen activation suggests that angiostatin dose dependent manner replaces plasminogen in the binary enzyme-substrate complex uPA-Pg. In case of fibrin-stimulated plasminogen activation by tPA, both zymogen and tPA are bound to fibrin with formation of the effective triple tPA-Pg-fibrin complex. Angiostatin replaces plasminogen both from the fibrin surface and from the enzyme-substrate tPA-Pg complex that leads to a decrease in k(Pg) and an increase in K(Pg) of plasminogen activation. Inhibition constants by angioststin (Ki) of plasminogen-activator activities of uPA and tPA determined by Dixon method were found to be 0.59 +/- 0.04 and 0.12 +/- 0.05 microM, respectively.

Inhibitory effect of angiostatins on activity of the plasminogen/plasminogen activator system.

Angiostatins, kringle-containing fragments of plasminogen, are potent inhibitors of angiogenesis. Effects of three angiostatin forms, K1-3, K1-4, and K1-4.5 (0-2 microM), on the rate of native Glu-plasminogen activation by its physiological activators in the absence or presence of soluble fibrin were investigated in vitro. Angiostatins did not affect the intrinsic amidolytic activities of plasmin and plasminogen activators of tissue type (tPA) and urokinase type (single-chain scuPA and two-chain tcuPA), but inhibited conversion of plasminogen to plasmin in a dose-dependent manner. All three angiostatins suppressed Glu-plasminogen activation by tcuPA independently of the presence of fibrin, and the inhibitory effect increased in the order: K1-3 < K1-4 < K1-4.5. The inhibitory effects of angiostatins on the scuPA activator activity were lower and further decreased in the presence of fibrin. Angiostatin K1-3 (up to 2 microM) had no effect, while 2 microM angiostatins K1-4 and K1-4.5 inhibited the fibrin-stimulated Glu-plasminogen activation by tPA by 50 and 100%, respectively. The difference in effects of the three angiostatins on the Glu-plasminogen activation by scuPA, tcuPA, and tPA in the absence or presence of fibrin is due to the differences in angiostatin structures, mechanisms of action, and fibrin-specificity of plasminogen activators, as well as due to the influence of fibrin on the Glu-plasminogen conformation. Angiostatins in vivo, which mimic plasminogen-binding activity, can inhibit plasminogen activation stimulated by various proteins (including fibrin) of extracellular matrix, thereby blocking cell migration and angiogenesis. The data of this work indicate that the inhibition of Glu-plasminogen activation under the action of physiological plasminogen activators by angiostatins can be implicated in the complex mechanism of their antiangiogenic and antitumor action.

[The in vitro cross-effects of inhibitors of renin-angiotensin and fibrinolytic systems on the key enzymes of these systems].

The effects of hypotensive agents (captopril, enalaprilate, and lisinopril) on the activities of components of the fibrinolytic system (FS) and the effects of antifibrinolytic agents (6-aminohexanoic acid (6-AHA) and tranexamic acid (t-AMCHA)) on the activities of angiotensin converting enzyme (ACE) were studied in vitro. Enalaprilate did not affect the FS activity. Captopril considerably inhibited the amidase activities of urokinase (u-PA), plasminogen tissue activator (t-PA), and plasmin ([I]50 (2.0-2.6) +/- 0.1 mM), and the activation of Glu-plasminogen affected by t-PA and u-PA ([I]50 (1.50-1.80) +/- 0.06 mM), which may be due to the presence of a mercapto group in the inhibitor molecule. Lisinopril did not affect the amidase activities of FS enzymes, but stimulated Glu-plasminogen and u-PA activation and inhibited activation of t-PA-fibrin-bound Glu-plasminogen ([I]50 (12.0 +/- 0.5) mM). Presumably, these effects can be explained by the presence in lisinopril of a Lys side residue, whose binding to lysine-binding Glu-plasminogen centers resulted, on the one hand, in the transformation of its closed conformation to a semi-open one and, on the other hand, in its desorption from fibrin. Unspecific inhibition of the activity of ACE, a key enzyme of the renin-angiotensin system, in the presence of 6-AHA and t-AMCHA ([I]50 10.0 +/- 0.5 and 7.5 +/- 0.4 mM, respectively) was found. A decrease in the ACE activity along with the growth of the fibrin monomer concentration was revealed. The data demonstrate that, along with endogenous mediated interactions, relations based on the direct interactions of exogenous inhibitors of one system affecting the activities of components of another system can take place.