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Biomedical subjects

M A Azhigirova

Publications and source records attributed to M A Azhigirova.

At least 19 recordsLinked to original sources
PubMed2000

Characterization of the heme iron in pyridoxylated hemoglobin cross-linked by glutaraldehyde using Mössbauer spectroscopy.

The heme iron in human adult hemoglobin modified by both pyridoxal-5'-phosphate and glutaraldehyde was characterized by Mössbauer spectroscopy and compared with non-modified hemoglobin. Mössbauer spectra of the samples were measured at 87 and 295 K (1yophilized form) and at 87 K (frozen solution). The values of quadrupole splitting for the oxy-form of modified hemoglobin were found to be lower than those of the oxy-form of hemoglobin without modifications in lyophilized form and frozen solution, respectively. On the other hand, the values of quadrupole splitting for the deoxy-form of modified and non-modified hemoglobins in frozen solution were the same. The Mössbauer spectra of the oxy-form of modified hemoglobin were also analyzed in terms of the heme iron non-equivalence in alpha- and beta-subunits of tetramer. The differences of the tendencies of temperature dependencies of quadrupole splitting for the oxy-form of modified and non-modified hemoglobins in lyophilized form were shown. These results indicated that the heme iron electronic structure and stereochemistry were changed in the oxy-form of pyridoxylated hemoglobin cross-linked by glutaraldehyde.

Adult↗
PubMed1993

[Comparative study of chemically modified hemoglobins as a basis for oxygen-carrying blood substitutes].

The series of hemoglobin derivatives were obtained with the different content of the polymer fractions; their comparative study by the methods of gel-chromatography and SDS-electrophoresis was conducted and the estimation of their functional, rheological, colloid-oncotic properties and the degree of immunogenicity was carried out in order to choose the optimal substance judging by their physico-chemical, gas-carrying and antigenic characteristics. It was shown that the polymerised hemoglobin with the polymer content of 25-30% has the optimal properties as the oxygen carrier. The 10% solution of this compound possesses oxygen-carrying characteristics identical to donors erythrocytes, viscosity of no more than 1.5 sP, colloid oncotic pressure in the range of 15-17.5 torr, it practically doesn't influence the aggregation of the formula blood elements and has low antigenicity. The results obtained allow to consider this type of poly-hemoglobin as a potential oxygen-carrying blood substitute.

Biological Transport↗
PubMed1993

[Effect of polyhemoglobin composition on erythrocyte aggregation and circulation time in the vascular bed].

Aggregation of erythrocytes and circulation time of polyhemoglobins in blood plasma was estimated in the model of 50% blood loss compensation in vivo and in vitro using solutions of polyhemoglobins with different content of polymerized form (from 2-3% to 70-73%). Hemoglobin derivatives were characterized by HPLC, sedimentation analysis; the main functional properties of polyhemoglobins were evaluated as well as their influence on erythrocytes aggregation in vitro and in vivo on dogs. The optimal content of polymerized form (25-30%) was estimated which provides sufficient prolongation of circulation time and does not enhance the erythrocytes aggregation. The conclusion was made that influence on erythrocyte aggregation likewise functional properties and circulation time may be considered as criterion of optimal fractional composition and biocompatibility of the polyhemoglobins.

Animals↗
PubMed1992

[The fractional composition of immunoglobulin preparations studied by gel filtration on different carriers and by high-pressure liquid chromatography].

The fractional composition of immunoglobulin preparations produced by different manufacturing enterprises of this country has been studied by gel chromatography in columns packed with different carriers (Sephadex G-200 and ultragel AcA-34) and by high-performance liquid chromatography (HPLC). This study has revealed the nonstandard character of immunoglobulin preparations produced according to the same technological procedure (modified Cohn's method). The fractionation of immunoglobulins on different carriers with the use of different methods has yielded similar results confirmed by the statistical processing of the data. The results obtained in the study of the fractional composition of immunoglobulin preparations evidence that gel filtration with the use of ultragel and HPLC have greater resolving capacity in comparison with the method of gel filtration on traditionally used Sephadex G-200.

Chromatography, Gel↗
PubMed1992

[Study of humoral hemolytic factors in hemorrhage using chromatographic methods].

The kidney-dependent increase of the haemolytic activity of blood serum after acute decompensated blood loss was demonstrated in the experiments on rats. The preparative ion-exchange chromatography on DEAE-Toyoperal was used to separate the haemolytic active component of the posthaemorrhagic blood serum with the max value of the specific activity of 6.86 A/micrograms protein. The analysis of the separated component by size-exclusion chromatography on TSK-G3000-SW column indicated a molecular mass of 80-100 kDa. In injection in the circulatory system in in vivo experiments the dose-dependent effect of the action of separated component was demonstrated.

Animals↗
PubMed1991

[Study of chemically modified hemoglobin as an artificial oxygen carrier in the model of hemorrhagic shock in dogs].

Hemodynamic and gas-transporting properties of the chemically modified hemoglobin solution have been studied on the model of hemorrhagic shock in dog. It has been shown that the polymerized hemoglobin solution exerts the hemodynamic action just as the plasma substitute "polyglucin" does. However, in contrast to the latter, polyhemoglobin circulating in the vascular bed for a prolonged period of time increases the blood oxygen capacity and oxygen delivery to tissues with the resultant increase in body total oxygen taking-up.

Animals↗
PubMed1991

[Isolation of factor IX concentrate from cryosupernatant of donor's plasma].

Soviet anion-exchangers were comparatively studied to specify an optimal carrier useful for isolation of factor ix of the blood coagulation system from donor's blood cryosupernatant. The main criteria of gel selection were the yield and purification degree of factor IX, as well as its specific activity and concentration in eluates. It has been shown that DEAE-agarose 6B-CL, possessing pronounced activity with respect to specific sorption of factor IX, meets these requirements to the greatest degree.

Blood Donors↗
PubMed1991

[Study of functional properties of chemically-modified hemoglobin during circulation in the blood channel].

Functional activity of the solutions of chemically modified hemoglobins (Hb) with different structure had been investigated during the replacement of acute fatal blood loss in dogs. It was found the correlation between polymerization degree of Hb derivatives and alterations of its oxygen-carrying characteristics in the process of circulation. It was shown that decline of functional activity at the prolonged terms of circulation was more expressed for macromolecular Hb derivatives with heterogeneous structure. Therefore chemically modified Hb free from high molecular weight fractions may be considered as a potential oxygen-carrying fluids, because they are capable of more effective support of the oxygen transport level in the organism.

Animals↗
PubMed1990

[The structuro-functional heterogeneity of an artificial oxygen carrier based on hemoglobin].

Pyridoxylated polymerized hemoglobin (PP-Hb) was fractionated by the method of high pressure liquid chromatography, Molecular weight distribution, oxygen carrying capacity and antigenic characteristics of separated fractions have been investigated. It was demonstrated that a fraction may be separated from the crude PP-Hb, which is greatly homogeneous if structural and functional characteristics are concerned, and also optimal according to the parameters investigated. So, by a corresponding fractionation method it is possible to overcome the main limitation for use of PP-Hb as an artificial oxygen carrier--its heterogeneity.

Blood Substitutes↗
PubMed1990

[The effect of the degree of hemoglobin polymerization on its interaction with the body].

Solutions of pyridoxylated polyhemoglobin (PPHb) with the different degree of polymerization (0-53%) were injected intravenously into rats (1 g/kg). The quantity of PPHb, circulating in plasma, being excreted with the urine and accumulated in the organs have been estimated during the first 6 hours after the infusion. During this period 25-40% of the injected PPHb have been found in the urine and 10-25% have been found in plasma, the percentage depending on the degree of polymerization. For all the substances studied 50% accumulation in organs have been observed, the fact of accumulation being proved by the pathologicoanatomic studies. In the present study the localization and the quantity of hemosiderin granules in the organs was the same for the modified hemoglobins with the different degree of polymerization.

Animals↗
PubMed1988

[Study of structural heterogeneity of polymerized hemoglobin using biochemical and immunochemical methods].

The structural heterogeneity of crosslinked pyridoxalated hemoglobin (polyHb-PLP) have been investigated by the methods of gel-filtration, isoelectric focusing and immunoelectrophoresis. It was established that the heterogeneity of poly-Hb-PLP is mainly depicted by polydispersion of molecular weight and less by the changes in the isoelectric properties. The qualitative difference has been shown between the immunochemical properties of the native hemoglobin and poly-Hb-PLP, which gives the suggestion of the formation of new antigenic determinants as a result of chemical modification and of more expressed antigenicity of modified hemoglobin compared with native protein. Poly-Hb-PLP has wide antigenic spectrum that corresponds to its structural heterogeneity. The data obtained suggest that the decrease in the antigenic activity of poly-Hb-PLP can be achieved by the lowering of the part of high molecular weight components.

Blood Substitutes↗
PubMed1988

[Biochemical properties of intramolecularly cross-linked hemoglobin].

The chemical modification of hemoglobin was conducted with the help of bifunctional crosslinking agent--glutaraldehyde. By SDS-polyacrylamide gel electrophoresis and gel-filtration it was shown that the final product contained 70% of modified protein which consisted of non-dissociating hemoglobin dimers and tetramers. It was also shown that the chemical modification didn't produce significant changes in the oxygen-transporting properties of the starting hemoglobin, but had influence on the character of the interaction with the allosteric regulator of reversible oxygenation (pyridoxal-5'-phosphate). The half-disappearance period in animals of the intramolecularly crosslinked hemoglobin was two times longer in comparison with the native protein.

Animals↗
PubMed1986

[Hemoglobin polymers during their circulation in the vascular bed of animals].

The effect of molecular mass of 1 g/kg hemoglobin (Hb) modified by glutaraldehyde and pyridoxal-5'-phosphate on the duration of Hb presence in the rabbit circulation was studied. Hb concentration and met-form content were measured in plasma samples taken 5 min, 6, 18 and 24 h after the injection. Gel and ion exchange chromatography was performed. Predominant clearance of low-molecular fractions within the first 6 h of circulation was shown, it was followed by a rise in high-molecular fraction (greater than 300,000) content, that might be caused by the interaction of modified Hb with plasma proteins. This corroborates the decrease in the overall charge of the circulating fractions.

Animals↗
PubMed1986

[Keto acids as regulators of hemoglobin reversible oxygenation].

Several ketocarbonic acids covalently attached to the protein moiety of hemoglobin were tested as reversible oxygenation regulators. Two monocarbonic acids (glycoxylic and piruvic) and bicarbonic--alpha-ketoglutaric-acid were used for remoglobin modification. Functional properties and isoelectrical characteristics of modified hemoglobin were recorded. The binding of these acids to hemoglobin was shown to affect the net charge of hemoglobin molecule and the nature of its interaction with allosteric effectors (O2; CI-; H+). Under the influence of glyoxylic acid, the gas-transporting characteristics of hemoglobin underwent most distinct changes approaching those of the human whole blood.

Chromatography, DEAE-Cellulose↗