[Soluble fibrin and D-dimer at normal pregnancy and pregnancy with risk of miscarriage].

ELISA for soluble fibrin (SF) quantification has been elaborated on the basis of our fibrin-specific monoclonal antibodies (mAb). Epitope for these mAb is localized in fibrin fragment Bbeta118-134. The method was used on the blood plasma of healthy pregnant women (control group) and pregnant women with the risk of fetal loss (RFL). The increased mean values of SF concentrations were observed at pregnancy with RFL as compared to the normal pregnancy at the terms from 4 to 24 weeks (17.87 +/- 3.15 mkg/ml and 9.03 +/- 1.58 mkg/ml accordingly, p < 0.05). A weak negative correlation between SF concentration and pregnancy term was found at RFL (r = -0.201, n=35), while there was no correlation between these variables in control group (r = 0.004, n=28). The mean values of SF concentration estimated by semiquantitative test (by phosphates salting out of SF) were also higher at the pregnancy with RFL as compared to the normal pregnancy. However, the absolute values of SF concentrations determined by salting out method were essentially higher than in the case of ELISA. Immunoblot analysis with mAb 2d-2a (epitope for which in fibrin molecule encompasses peptide bond Bbeta14-15), showed that the main molecular component of SF at normal pregnancy and RFL was oligomeric fibrin desAA with possible incorporation of fibrinogen and/or fibrin desA which was not stabilized by factor XIIIa. D-dimer concentrations determined in blood plasma samples of pregnant women by ELISA varied in the range of 1-224 ng/ml at the pregnancy period from 4 to 37 weeks. There was positive correlation between D-dimer concentration and pregnancy term both at normal pregnancy and pregnancy with RFL (r = 0.765, n=33 and r = 0.712, n=44 correspondingly). The mean values of D-dimer concentration at various terms of normal pregnancy and pregnancy with RFL did not vary considerably. Thus SF but not D-dimer quantification may give useful diagnostic information at the pregnancy with RFL.

[Quantification of D-dimer and soluble fibrin in blood plasma of people with ischemic heart disease and hypertension]. / Kolichestvennoe opredelenie D-dimera i rastvorimogo fibrina v plazme krovi cheloveka pri ishemicheskoi bolezni serdtsa i gipertonicheskoi bolezni.

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.

[Fibrin fragment beta 15-118. Inhibitory and complex-forming properties]. / Fibrinovyi fragment beta 15-118. Ingibitornye i kompleksoobrazuiushchie svoistva.

Peptide beta 15-118 isolated from desAABB-NDSK preserves fibrin polymerization active site "B", inhibits polymerization process at 12 degrees C, eliminates the inhibitory properties of plasmin D-D-fragment but does not influence inhibitory properties of a D-monomer fragment. Complex formation between peptide beta 15-118 and both D- and D-D fragments was electrophoretically demonstrated. Peptide beta 15-118 forms more stable complex with the D-D fragment which does not dissociate in the medium of polymerizing fibrin as the complex of the peptide with monomer D fragment does. Gel filtration data confirm dimerization of D-monomer fragments after their complexing with beta 15-118. This phenomenon suggests that mutual affinity of D-domains in fibrin increases after loci interactions of the "B"-"b" type.

[Study of the polymerization of fibrin using monoclonal antibodies 2D-2A and their Fab-fragments]. / Issledovanie polimerizatsii fibrina s pomoshch'iu monoklonal'nykh antitel 2D-2A i ikh Fab-fragmentov.

It has been shown that monAb's 2d-2a and their Fab-fragments are specific and effective inhibitors of fibrinogen clotting. Only one IgG molecule of monAb's 2d-2a can bind with one of their epitopes situated around peptide bond B beta Arg14-Gly15 in dimer fibrinogen molecule reducing the rate of protofibril lateral association and clot turbidity with only one fibrinopeptide B splitting off per fibrinogen molecule by thrombin. But two molecules of Fab-fragments of monAb's 2d-2a join to both of their epitopes and inhibit fibrinogen clotting dramatically without clot formation and with no fibrinopeptide B splitting off. These data suggest that the site of fibrin protofibril lateral coalescence is localized in NH2-terminal part of fibrin (ogen) B beta-chain, i.e. central E-domain of fibrin molecule takes part in protofibril lateral association. The mutual space orientation of NH2-terminal regions of fibrinogen B beta-chains is discussed.

[Study of fibrinogen-fibrin cryocomplexes by a quantitative analysis of N-terminal amino acids]. / Issledovanie kriokompleksov fibrinogena i fibrina metodom kolichestvennogo analiza N-kontsevykh aminokislot.

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.

[Properties of 2 fibrin monomer forms which differ in the degree of thrombin activation. Relation of these 2 forms to specific polymerization inhibitors]. / Svoista dvukh form monomernogo fibrina, razlichaiushchikhsia po stepeni aktivatsii trombinom. Otnoshcnie polimerizatsii dvukh form fibrina k spetsificheskim ingibitoram.

The inhibitory effect of fibrinogen and its fragment D on the clotting of two fibrin monomer species has been studied. One of them (f0) lacks peptides A and B, the other (fB) preserves peptides B. The inhibitors retard the clotting of f0 but fail to influence fB polymerization. This means that the peptide B removal and appearance of the active site B in the central (E) domain of the fibrin molecule is a prerequisite for the inhibitory effect of fibrinogen or fragment D. The specificity of this effect suggests that fragment D and the periferal D-domains of fibrinogen possess a special site (B') which reacts selectively with the fibrin active site B to block polymerization. The present investigation has demonstrated the importance of the H-bond system formation for B-B' sites interaction.

[Properties of 2 fibrin monomer species which differ in the degree of thrombin activation. Characteristics of successively appearing active sites]. / Svoistvadvukh form monomernogo fibrina, razlichaiushchikhsia po stepeni aktivatsii trombinom. Kharakteristika posledovatel'no obrazuiushchikhsia aktivnykh tsentrov.

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.

[Changes in the primary structure of rabbit muscle aldolase under the influence of valine against a background of prolonged fasting]. / Zminy pervynnoï struktury aldolazy míaziv kroliv pid vplyvom valinu na foni tryvaloho holoduvannia

The primary structure of the muscle aldolase molecule was studied as affected by semilethal doses of valine administered the abdominal cavity of the rabbits after a long fasting. It is established that in spite of differences in the amino acid composition of the protein, uniformity of the peptides distribution in the process of bromo-cyanogen fragments elution and the total amount of amino acid residues in the identical fragments are maintained. Changes are found only in the point-replacements by amino acids in C-fragment of the molecule (asparagine is replaced by valine and threonine by serine).