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Biomedical subjects

I P Baskova

Publications and source records attributed to I P Baskova.

At least 19 recordsLinked to original sources
PubMed1992

Inhibition of plasma kallikrein. Kininase and kinin-like activities of preparations from the medicinal leeches.

The medicinal leech salivary gland secretion deprived of hirudin antithrombin activity inhibits amidolytic (substrate S-2302) and kininogenase (substrate kininogen) activities of plasma kallikrein, the main component of the intrinsic mechanism of blood coagulation. It therefore possesses high anticoagulant properties. Kininase (substrate bradykinin) activity of leech saliva and extracts from the medicinal leeches, as well as kinin-like effects of extracts heated at 100 degrees C have been detected. The last one is correlated with the hyperalgetic property of the heated extract. An analgetic effect was observed with the unheated extract but not with leech saliva after intranasal administration to rats.

Amino Acid Sequence↗
PubMed1992

Use of the medicinal leech in the treatment of ear diseases.

Medicinal leeches (Hirudo medicinalis) and the native secretion of their salivary glands diluted with saline (5 times) were successfully used for the treatment of some ear diseases: tinnitus caused by inner-ear affections, acute external otitis and chronic otitis media. The effect of diluted leech saliva injected into the region of the mastoid process by microelectrophoresis was 25-30% lower than that of the medicinal leeches.

Acute Disease↗
PubMed1992

[Monomerization of the fragment D dimer of stabilized fibrin by a secretion from the medicinal leech salivary gland].

The salivary gland secretion of the medicinal leech catalyzes the conversion into monomeric form of the fragment D dimer, the product of limited proteolysis of stabilized fibrin. Analysis of N-terminal sequences revealed identical fragments for the D-dimer gamma-gamma-chains and the D-monomer gamma-chains formed via this reaction and established the presence of only one N-terminal amino acid (Ser). These results provide evidence for the preservation of integrity of the polypeptide chains during monomerization of the D-dimer.

Amino Acid Sequence↗
PubMed1991

Destabilase, the novel epsilon-(gamma-Glu)-Lys isopeptidase with thrombolytic activity.

The salivary gland secretion of the leech Hirudo medicinalis contains the enzyme destabilase which hydrolyses epsilon-(gamma-Glu)-Lys cross-links in stabilized fibrin. Accumulation of Glu residues instead of the original Gln residues leads to spontaneous depolymerization of destabilized fibrin. L-gamma-Glu-p-nitroanilide; L-gamma-Glu-dansylcadaverine and isopeptide epsilon-(gamma-Glu)-Lys are low-molecular-weight substrates of destabilase. Destabilase probably exists in molecular forms of molecular weight 50,000, 25,000 and 12,300. The protein part of destabilase is covalently bound to a lipid component of molecular weight 390, which has little cross-reactivity to 6-keto-prostaglandin F1 alpha antiserum. The lipid component ensures the hydrophobic properties of destabilase, inhibition of platelet aggregation, protection from proteolysis and absorption from the intestine into blood during oral administration to experimental animals. It also ensures the protective antithrombotic effect. Almost total (80-100%) thrombolysis of preformed thrombus in the rat was achieved by destabilase 70-100 h after i.v. injection or oral administration.

Animals↗
PubMed1990

[Kinetics of L-gamma-Glu-pNA hydrolysis by destabilase, the enzyme from the medicinal leech Hirudo medicinalis].

The molecular mass of destabilase isolated from the medicinae leech Hirudo medicinalis was found to be equal to 12.3 kDa. A kinetic analysis of the sole presently known synthetic substrate, L-gamma-Glu-pNA, showed that the enzyme is relatively stable to heating (5 min, 70 degrees C); the pH optimum lies at 7.0-8.5. The enzyme has a specific activity of 0.15 x 10(-9) mol.s-1.mg-1; Km = 2.2 x 10(-4) M, kcat is 3.53 x 10(-3) s-1 (pH 8.0, 37 degrees C).

Animals↗
PubMed1990

[Hydrolysis of the isopeptide epsilon-(gamma-glutamyl)-lysine by destabilase from the medicinal leech Hirudo medicinalis].

Using amino acid analysis, the ability of destabilize to hydrolyze the epsilon-(gamma-Glu)-Lys isopeptide bond was demonstrated. Incubation of the epsilon-(gamma-Glu)-Lys isopeptide with the enzyme was accompanied by a decrease of the amount of the isopeptide and an increase of equimolar amounts of lysine and glutamic acid. Complete hydrolysis of the isopeptide was observed after 96 hour incubation with destabilize. It was supposed that the isopeptide is a less specific substrate for destabilize compared to L-gamma-Glu-pNA.

Amino Acids↗
PubMed1990

[The effect of preparations of Hirudo medicinalis leeches on DNA methylation in the rat liver].

The effect of the salivary gland secretion and dialysable part of the homogenate of the leeches Hirudo medicinalis on the methylation of DNA in the rat liver after the intraperitoneal injection and perfusion of isolated liver has been analysed. The maximum concentration of 5-methylcytosine is observed 1 h later the injection of preparations: for the salivary gland secretion the increase is 39%, for the dialysate of leech homogenate is 28%. The 5-methylcytosine content increases on 28% after the perfusion of isolated liver with the leech saliva and after the dialysate of the leech homogenate--on 20%. No other changes in DNA content is observed. It is suggested that the DNA-methylation of the liver cells is due to the penetration of biologically active substances produced by the medical leech into the cell-targets accompanied by the forming of corresponding ligand-receptor complexes.

5-Methylcytosine↗
PubMed1988

Thrombolytic agents of the preparation from the medicinal leeches.

The thrombolytic effect of an extract from medicinal leeches orally administered to rats was shown. This effect depends on the number of administrations and on the concentration of extract. It is due to the leech prostaglandins and enzyme destabilase. After the extraction of prostaglandins by ethylacetate the thrombolytic effect diminished by 45%. It is supposed that the leech-prostaglandins, like prostacyclin and its stable analogous, induce the release of tissue plasminogen activator from vessel walls. The thrombolytic effect of destabilase was demonstrated in experiments in vitro. We observed the phenomenon of increasing of glutaminase activity of citrate blood and the appearance of amidolytic and destabilase activity.

Animals↗
PubMed1988

Antithrombotic effect of preparations from the leeches Hirudo medicinalis.

Antithrombotic effect of leech salivary gland secretion was maximal after intravenous administration into rats and was slightly decreased in cases of peroral administration. Blood from leech intestinal tract and leech homogenate exhibited less distinct antithrombotic action. Effect of these preparations was maintained after peroral administration. The antithrombotic effect of the leech preparations did not depend on their antithrombic activity caused by hirudin. These leech preparations appear to elongate a period of blood plasma recalcification caused by kallikrein inhibitor as well as apparently due to their capacity to inhibit aggregation of the thrombocytes.

Administration, Oral↗
PubMed1979

[Inactivation of factor X by plasmin].

Plasmin does not activate factor X into the enzyme--factor Xa. On the contrary, the enzyme inactivates factor X, rendering it incapable of conversion into factor Xa during incubation in 25% sodium citrate. After proteolysis by plasmin the prothrombin preparations contaminated with factor X lose their ability to generate thrombin. This ability is partially restored by an addition of factor X.

Factor X↗
PubMed1978

[Effect of hirudin on hormonally caused activation of nonenzymatic fibrinolysis in immobilization stress].

The specific inhibitor of thrombin-hirudin was used for studying the mechanism of activating effect of ACTH and adrenaline upon the unenzymatic fibrinolysis (UEF), the latter characterizing the function of the anticoagulating system (ACS). Simultaneous administration of ACTH and hirudin to animals subjected to the immobilization stress did not reduce the effect of ACTH upon UEF, while simultaneous administration of adrenaline and hirudin revealed a diminished effect of the former. This suggests different mechanisms of ACTH and adrenaline effects upon UEF: the stimulating effect of noradrenaline is realized through thrombinogenesis followed by activation of the ACS function and by an increase of UEF and therefore inhibitable by hirudin which form an inactive complex with thrombin. While the stimulating effect of ACTH upon UEF is exerted, apparently, not through thrombinogenesis and hence is valid even in presence of hirudin. Hirudin proper exerts no effect upon UEF.

Adrenocorticotropic Hormone↗
PubMed1978

[Mechanisms of non-specific prothrombin activation].

The review of different mechanisms of non-physiological non-specific prothrombin activation is given as compared with the specific activation by the factor Xa. The use of snake venom enzymes or staphylocoagulase makes possible the thrombin generation from pathological forms of prothrombin lacking of gamma-carboxyglutamic acid and incapable of complete activation into thrombin by the specific activator, factor Xa. This fact stimulated the use of non-specific activators in medicine. Investigation of non-specific prothrombin activators made possible to reveal and to trace pathways of the formation of thrombin active site. It is demonstrated that prothrombin, like other serine proenzymes (trypsinogen, chymotrypsinogen), has already formed active site. This site can be revealed under changes of the conformation of the prothrombin molecule due to the chemical modification or the complex formation with staphylocoagulase.

1-Carboxyglutamic Acid↗
PubMed1977

[Determination of the secondary prothrombin structure under different degrees of citraconylation by means of ring dichroism].

A process of spontaneous activation of bovine prothrombin under acylation of cytacone anhydride is studied by means of ring dichroism and disc electrophoresis in sodium dodecylsulphate. Ring dichroism data have shown that native prothrombin contains 14% of alpha-helical structures, 36% of beta-structures and 50% of random coil. Cytraconylation results in a fragmentation of native prothrombin chain and is accompanies by the decrease of alpha-helical regions in the fragments formed. Poly-L-lysine, modified by citracone anydride, does not form alpha-helical regions.

Chemical Phenomena↗
PubMed1977

[Changes of prothrombin activity by plasmin immobilized on L-lysine Sepharose 4B].

It is demonstrated that the method of immobilization of human plasmin by its adsorption on L-lysine-Sepharose 4B can be successfully applied for bovine plasmin isolation. Proteolysis of bovine prothrombin by bovine prothrombin by bovine plasmin preparations of high caseinolytic activity results in the increase of prothrombin level. Prothrombin proteolysis by bovine plasmin preparations of high caseinolytic activity results in the decrease of prothrombin level.

Animals↗
PubMed1977

[Activation of plasma Factor XIII by acetylated thrombin].

It has been demonstrated that acetylated thrombin (thrombin-esterase), having practically no coagulating activity but possessing high esterase activity, is capable to activate factor XIII. This ability, however, is 2 times lower as compared to that of native thrombin.

Acetylation↗