PubMed Health⌕ Search

Biomedical subjects

E V Lugovskoĭ

Publications and source records attributed to E V Lugovskoĭ.

At least 19 recordsLinked to original sources
PubMed2000

[Monoclonal antibodies as an instrument to study fibrin polymerization].

Examples of using monoclonal antibodies (MAb) for studying the fibrin polymerization mechanism are considered. MAb with epitopes situated in the fibrin polymerization sites or in the recognition sites of enzymes thrombin, plasminogen, and factor XIII, which are the functional partners of fibrin, are primarily discussed. The MAb to epitopes in various regions of A alpha, B beta, and gamma polypeptide chains of the functionally important E, D, and alpha C domains of fibrin are successively described.

Amino Acid Sequence↗
PubMed1990

[Platelet aggregation induced by fibrinmonomer and the effect of the heparin-adrenaline complex or plasmin on this process].

Addition of purified fibrin-monomer in a concentration of 0.5 mg/ml induces aggregation in a suspension of washed rat platelets in the absence of aggregants. Maximum aggregation takes place 1-3 min after fibrin-monomer addition, and then the disaggregation phase follows. Complex heparin compounds with adrenalin or plasmin possessing antipolymerization and fibrinolytic activity with respect to ++non-stabilized fibrin prevent, or to a great extent decrease fibrin-monomer-induced aggregation of washed platelets.

Animals↗
PubMed1987

[Kinetics of glu- and lys-plasminogen activation by the tissue activator in a fibrin clot].

Using a modified procedure for measuring the time of fibrin clot lysis, the kinetics of Glu- and Lys-plasminogen activation by the tissue activator was studied. Within the plasminogen concentration range of 0.4-100 nM the rate of activation of both protein forms obeys the Michaelis-Menten kinetics. At Lys-plasminogen concentration equimolar to that of fibrin, the rate of activation of the former decreases down to that of Glu-plasminogen activation. The kinetic constants for Glu- and Lys-plasminogen activation (Km) are equal to 0.055 and 0.013 microM; k = 0.19 and 0.21 s-1, respectively. The Km values for fibrin-bound Glu- and Lys-plasminogen are equal to 0.25 nM and 8 nM, respectively (k = 0.08 and 0.26 s-1, respectively). It is assumed that the tissue activator exhibits a higher affinity for the Glu-plasminogen--fibrin complex than for the Lys-plasminogen-fibrin complex.

Fibrin↗
PubMed1985

[Interaction of fibrinogen with two forms of fibrin differing in the degree of activation by thrombin].

The inhibitory effect of fibrinogen in the clotting of two fibrin monomer species--f-desAA and f-desAABB--was studied. The concentration dependence of this effect for two fibrin forms was found to be of the same character. This fact indicates that the modifying influence of fibrinogen proposed earlier in relation to f-desAABB also takes place in the case of f-desAA. However, an equal inhibitory effect is achieved for f-desAA at much higher fibrinogen concentrations than that for f-desAABB. The inhibitory effect of fibrinogen is greater at higher ionic strengths for both fibrin forms, but in the case of f-desAA this effect is more pronounced. The role of fibrin polymerization sites formed after fibrinopeptides B removal in initial fibrin polymerization and in F-f-desAABB interaction is discussed.

Animals↗
PubMed1983

[Study of fibrinogen-fibrin cryocomplexes by a quantitative analysis of N-terminal amino acids].

The reaction between fibrinogen (F) and thrombin (0.003 NIH/ml) has been investigated under physiological conditions. The action of thrombin was inhibited in various time intervals including gel point (4 h), and the reaction mixtures were allowed to stand 0 degrees C. The F-to-des-AA-fibrin (f) ratios were determined both in the initial reaction mixtures and in corresponding cryoprecipitants by the method of N-terminal amino acids quantitative analysis. It is found that the F/f ratio in the cryoprecipitant depends on the F/f ratio in the initial mixture at 37 degrees C. The F/f = 1 ratio in cryoprecipitant previously found by Shainoff and Page is valid only for the initial F/f = 7 ratio. But the F/f value in cryoprecipitants varies in favour of F or f components, if the F/f ratio increases or decreases in the initial mixture at 37 degrees C, respectively. A possible mechanism of various fibrinogen-fibrin cryocomplexes formation is discussed.

Animals↗
PubMed1983

[Analysis of the stability of the intermediate fibrin polymers formed in a fibrinogen-thrombin system].

Intermediate fibrin polymers formed from fibrinogen at low thrombin concentrations under physiological conditions are studied for their stability. Smith's statement that intermediate fibrin oligomers are inert molecules whose further self-assembly is possible only under additional thrombin activation was not supported. It is shown that the intermediate fibrin polymer stability at pH 7.4 is not high because of a strong tendency to aggregation and the higher molecular weight of the polymer the less its stability. The polymer stability in solution increases with pH. Stability of soluble fibrin complexes in solution depends on their size, defined by environmental conditions and on the quantity of fibrinogen present.

Animals↗
PubMed1978

[Properties of 2 fibrin monomer species which differ in the degree of thrombin activation. Characteristics of successively appearing active sites].

Some properties of intermediate and final products of fibrinogen activation by thrombin have been studied. The intermediate (fB) lacks peptide A, the final fibrin (fo)--A and B peptides. Peculiar pH-dependent differences have been observed when examining the effect of ionic strength on polymerization rate of fo and fB. Intermolecular links present in fo polymer are found to be stronger than those of fB polymer. Curves of clot turbidity vs pH for fo and Fb do not coincide. Considering these results together with the literature data on the fibrin-polymer H-bond system one may assume that there are much more H-bonds in fo polymer than in its fB variant. Polymerization of fB has been found to be practically unaffected by higher NaCl concentrations which activate fo polymerization. Our and literature evidence lead to the conclusion that the active site (contact region), generated by the release of the peptide A, effects polymerization through electrostatic and H-bonding, whereas on the removal of the peptide B another active site arises of which a system of H-bonds and hydrophobic interactions are characteristic.

Animals↗
PubMed1976

[Electrophoretic fractions and NH2-terminal amino acids of high-molecular tryptic fragments of fibrinogen and fibrin].

The electrophoretic and NH2-terminal analyses were performed for D and E fragments obtained by tryptic digestion of bovine fibrinogen and fibrin under various conditions. The preparations of fragment D were heterogeneous, they were separated by polyacrylamide gel electrophoresis into a number of electrophoretic components with molecular weight ranging from 65 000 to 85 000. NH2-terminal analysis revealed from 6 to 8 NH2-terminal amino acids: Ser, Gly, Thr, Asp, Gly, Lys, Gln, Asn. Their composition and quantitative ratios were found to vary depending on the conditions of the fragment D production. The electrophoregrams showed that with Ca++ in the medium the enzymatic splitting of fibrinogen was limited. Fragment D obtained from fibrinogen without Ca++ was electrophoretically rather similar to that obtained from fibrinogen at Ca++ optimal concentration. Taking into consideration a very high specific anti-coagulational activity of these two fragment D preparations, one may conclude that both the polymerized state of protein molecules and the presence of Ca++ stabilize the specific molecular structure, that favorus the preservation of specific inhibitory activity in fragment D. According to the NH2-terminal analysis data, fragment E derived from fibrinogen hydrolyzed in the presence of Ca++ optimal concentration is also heterogeneous. The following amino acids were found: Tyr, Lys, His (main ones) and Gly, Ser, Thr, Val (minor ones). As to molecular weight determined by electrophoresis, fragment E appears to be homogeneous.

Animals↗
PubMedDate not supplied

[The role of calcium ions in fibrin polymerization].

The article reviews the literature and authors' own data on the role of Ca ions in blood coagulation, namely, in the process of the formation of highly ordered fibrin clot. It has been shown that the main role of Ca2+ is the timely formation and stabilization of fibrin polymerization sites at all successive stages of the fibrin polymerization process.

Animals↗
PubMedDate not supplied

[Functional and diagnostic significance of A-, Bbeta 1-42 and Bbeta 15-42 peptide fragments of fibrin(ogen)].

A scheme of in vitro formation and hydrolysis of the fibrin clot is suggested. This scheme considers the data concerning a cofactor role of fibrin in activation of polymerization and fibrinolysis. Such parameters of a number of components as concentration of A-, B beta 1-42-and B beta 15-42 peptides and of other fragments of fibrinogen which allow characterizing a state of hyperfibrinolysis, hyperclotting or dynamic equilibrium of these systems are selected in the scheme.

Blood Coagulation↗
PubMedDate not supplied

[Fibrin-depolymerization activity and the antiplatelet effect of small cyclic and linear proline-containing peptides].

In our study of the effect of proline-containing linear di- and tri-peptides (Pro-Gly, Pro-Gly-Pro) and cyclic peptide cPro-Gly in vitro, we have found that they show depolymerizing activity towards the nonstabilized form of fibrin in the presence and in the absence of sigma-aminocapronic acid, an inhibitor of enzymatic fibrinolysis. The peptides have an inhibitory effect on platelet aggregation in platelet-enriched blood plasma, when the process is induced by ADP, they also diminish the activity of factor XIIIa in blood plasma.

Animals↗
PubMedDate not supplied

[Quantification of D-dimer and soluble fibrin in blood plasma of people with ischemic heart disease and hypertension].

The method of D-dimer quantification in the human blood plasma has been developed using monoclonal antibodies 111-3b and II-4d. The method has been verified on the blood plasma of the patients with ischemic heart disease with and without stenocardia and with hypertension. The results showed that at ischemic heart disease with and without stenocardia and at hypertension the quantities of D-dimer in the blood plasma were generally less than the highest normal level 500 ng/ml (64.3%, 76.2% and 95%, correspondingly). The semiquantitative measurements of soluble fibrin levels in blood plasmas of the patients with ischemic heart disease and hypertension have been performed. It has been shown that the quantity of soluble fibrin at these diseases range greatly from < 0.03 mg/ml to 0.15 mg/ml. There was no correlation between the quantities of D-dimer and soluble fibrin in blood plasmas of the patients. Electrophoresis in PAAG with SDS showed that the soluble fibrin at these diseases had the mo- lecular mass of the fibrin (ogen). Thus the soluble fibrin in blood plasmas analysed consisted mainly of fibrin desAA oligomers (may be with fibrinogen incorporation) which are not stabilized by the factor XIIIa.

Blood Protein Electrophoresis↗
PubMedDate not supplied

[Plasminogen activation by a tissue activator and effector properties of fibrinogen-N-terminal disulfide (N-DSK) fibrin complex].

Fibrinogen-NDSK complex is a model of protofibril having some features of the fibrin polymer structure. This complex has been studied for its ability to stimulate the plasminogen activation by t-PA. The fibrinogen-NDSK complex have increased the rate of plasminogen activation by t-PA as compared to fibrinogen or NDSK taken separately. This acceleration had slow and fast phases. Lys-plasminogen was activated more effectively as compared to glu-plasminogen. The kinetic parameters of glu- and lys-plasminogen activation at fast phase were: Km--0.18 and 0.015 mu/M, Kkat--0.27 and 0.06 s-1, respectively. Fibrinogen X2--fragments, deprived of alpha C-domains and NH2-end peptides of bB-chains, formed complexes with NDSK, which however did not stimulate the plasminogen activation by t-PA. These findings have shown that the fibrinogen-NDSK complex is an effective stimulator of the plasminogen activation by t-PA. The activating ability of the complex may be due to structures formed in the course of fibrinogen and NDSK polymerization as a result of alpha C-domain interaction.

Disulfides↗