Publications by authors named "Ovsepyan R"

This study presents a novel series of -acylated 1,2,4-triazol-5-amines and 1-pyrazol-5-amines, featuring a pyrazin-2-yl moiety, developed as covalent inhibitors of thrombin. These compounds demonstrated potent inhibitory activity, with derivatives and achieving IC values as low as 0.7 and 0.

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The search for new hemostatic materials remains a priority for researchers, as the problem of uncontrolled hemorrhage during surgical interventions or traumatic injuries represents a significant challenge. The objective of the study was to identify novel polysaccharide structures with enhanced hemostatic properties based on chitosan. The number of chitosan derivatives with two substituents was synthesized and characterized by H NMR, FTIR.

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We herein report the conventional and microscale parallel synthesis of selective inhibitors of human blood coagulation factor XIIa and thrombin exhibiting a 1,2,4-triazol-5-amine scaffold. Structural variations of this scaffold allowed identifying derivative , a potent 29 nM inhibitor of FXIIa, with improved selectivity over other tested serine proteases and also finding compound with 27 nM inhibitory activity toward thrombin. For the first time, acylated 1,2,4-triazol-5-amines were proved to have anticoagulant properties and the ability to affect thrombin- and cancer-cell-induced platelet aggregation.

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The actual coagulation status may be reliably measured using only highly sensitive global functional tests; however, they are not numerous and all of them have disadvantages. Thrombodynamics (TD), a novel global coagulation test, is sensitive to hypo- and hypercoagulable states. The main properties of this test were investigated, and its capabilities for hemostasis analysis were verified through pharmacodynamic monitoring of the most widely used anticoagulants, heparins.

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A new oral anticoagulant, dabigatran etexilate (DE, a prodrug of direct thrombin inhibitor (DTI) dabigatran), has been used clinically to prevent thrombosis. The assessment of dabigatran efficiency is necessary in some clinical cases, such as renal insufficiency, risk of bleeding, and drug interactions. However, a specific thrombin generation test (TGT) that is one of the most informative and sensitive to anticoagulant therapy (calibrated automated thrombinography (САТ)) shows a paradoxical increase of test parameters, such as endogenous thrombin potential (ETP) and peak thrombin, in patients receiving DE.

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Article Synopsis
  • Factor XIIa (fXIIa) is a protease that initiates coagulation and its inhibition is often needed for accurate testing.
  • Infestin-4 (Inf4), a specific inhibitor of fXIIa, was engineered with mutations to improve its effectiveness and reduce interference with other coagulation factors.
  • The most effective mutant, termed Mutant B, significantly inhibited fXIIa activity in plasma without affecting tissue factor-dependent coagulation, indicating its potential for use in coagulation diagnostics.
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Introduction: Standardization of pre-analytical conditions is the obligatory step for all potential diagnostic tests. Spatial clot growth (Thrombodynamics) is a new global hemostasis assay that considers spatial organization of coagulation. The principal parameter is rate of fibrin clot growth from the tissue-factor coated surface.

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Ammonia inhalation (0.84-1.07 mg/liter, 3 h) was accompanied by a 65% increase in ammonia concentration in mixed blood of intact rats.

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Sodium thiopental in the comatogenic (but not soporogenic) dose caused hyperammoniemia in rats. Blood ammonium level increased 3-fold within 3 h and 5-fold within 18 h. Blood urea level increased by one-third within 18 h against the background of unchanged creatinine level and hematocrit.

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