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Biomedical subjects

G V Samsonov

Publications and source records attributed to G V Samsonov.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

Modelling of gas transport function of erythrocytes in haemoglobin sorption immobilization.

Colloid-disperse systems based on haemoglobin sorption immobilization in reticular polyelectrolytes are proposed and investigated. The efficiency of oxygen transport of these systems is much higher than that of native haemoglobin and is comparable with the efficacy of gas transport of erythrocytes. This is believed to be due to highly selective sorption immobilization of haemoglobin in microdisperse forms of permeable carboxylic reticular polyelectrolytes. Microparticles exhibit high local concentration of haemoglobin, the protein mass being by one order of magnitude higher than that of the polymer carrier.

Biological Transport, Active↗
PubMedDate not supplied

[Modification of pancreatic ribonuclease activity in complexes with polyanions].

Carboxymethylcellulose, carboxymethylchitin, sulfoethylcellulose and dextrane sulfate interact with pancreatic ribonuclease. In comparison with ribonuclease activity the activity of formed complexes changes differently at the stages of transesterification and hydrolysis, and at each stage the effect of polymers on ribonuclease activity essentially differs. The use of ribonuclease-dextrane sulfate complex in the reaction of uridylyl-(3' leads to 5')-cytidine synthesis demonstrated that the protein synthetic activity completely retained when hydrolytic activity was considerably suppressed.

Animals↗
PubMedDate not supplied

[Study of ultrafiltration of trypsin solutions].

The dependence of the rate of trypsin ultrafiltration on the concentration, pressure and structure of membranes was studied. During ultrafiltration of diluted trypsin (0.3 mg/ml), water and sodium chloride the flow rate increased linearly with a pressure increase in the range of 0.4-4.2 kg/cm2. During ultrafiltration of trypsin solutions of a concentration of 1 mg/ml and over at a pressure of 2-3 kg/cm2 deviations from linear proportionality occurred which enhanced with an increase in the protein concentration and a decrease in membrane permeability.

Binding Sites↗
PubMedDate not supplied

[Trypsin concentration by ultrafiltration].

Criteria for the selection of membranes and optimal conditions for the trypsin concentration by ultrafiltration through acetylcellulose membranes have been developed. The possibility of a repeated concentration of trypsin by means of these membrances has been shown.

Trypsin↗
PubMedDate not supplied

[New principles of ion exchange preparative chromatography and their applications for isolation, purification and super purification of antibiotics].

New types of structurally segregated heteronetwork biosorbents with given parameters of heterogeneity and porosity have been developed. Physico-chemical characteristics of the biosorbents on the basis of which one can predict optimal structures of ion exchangers to be used in preparative chromatography of biologically active compounds were studied. A new principle of sequential displacement of ions of organic compounds, in particular antibiotics, adsorbed on selective biosorbents with a high adsorption capacity was developed, which enables purification and superpurification of the desired compound. The method is based on the effect of small thermodynamic shifts in physico-chemical parameters of the elution system, which results in preparative separation of substances with close properties and in purification of the desired compound from microadmixtures. The "small shift effect" is realized in the case of limiting thermodynamic and kinetic parameters of heterogeneous mass exchange and with biosorbents possessing a highly selective adsoprtion capacity.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Study of oligohemoglobin solutions in vitro and in vivo].

Solutions of oligohemoglobins (OHb) with middle molecular mass 100 x 10(3) = 400 x 10(3), obtained after polycondensation of hemoglobin with glutaric aldehyde as well as oligohemoglobin modified with pyridoxal-5-phosphate, were studied in vivo and in vitro (plethoric administration, isovolemic metabolic substitution, hemorrhagic shock; at a dose of 0.5-1.8 g/kg of body mass; dogs, rabbits, rats). With increase of the OHb molecular mass period of its circulation in blood was elevated; blood plasma protected OHb from autooxidation; half-life of OHb was about 12-18 hrs in isovolemic metabolic substitution and in hemorrhagic shock and about 5 hrs--in plethoric administration. During circulation molecular mass selection of OHb occurred, where low molecular fraction decreased and high molecular fraction--accumulated; sign and value of human erythrocyte charge were similar both in OHb solutions with concentration up to 5% and in physiological solution.

Animals↗
PubMedDate not supplied

[The effect of chemical modification of ribonuclease A by serum albumin on its catalytic properties].

The effect of chemical modification of ribonuclease A on its catalytic properties was studied. The kinetic parameters were calculated by using the Eisental and Cornish-Bowden direct linear plot. The Km value found for ribonuclease A conjugates with human serum albumin are comparable with those for the native enzyme whereas the Vmax value of the modified enzyme exceeds the maximum velocity of the enzymatic reaction of native ribonuclease A.

Catalysis↗
PubMedDate not supplied

[Effect of thermal treatment on the structure and biological properties of tuberculin].

The effect of heat treatment used in the course of tuberculin production by Mycobacteria tuberculosis cells on the structure and biological activity of tuberculin was studied. Methods of preparative and analytical gel-filtration were used. The largest quantity of the biologically active component was obtained after 2-hour heat treatment of the mycobacteria culture.

Bacteriological Techniques↗
PubMedDate not supplied

[Effect of chemical modification of hemoglobin on its biological activity].

Oligomeric hemoglobins were produced after polycondensation with glutaric aldehyde (OHb) as well as after modification with pyridoxal-5-phosphate (OHb-PLP). OHb exhibited high affinity to oxygen (P50 = 17 torr) as well as a decreased rate of the subunits cooperative interaction (n = 1.5-1.6); OHb-PLP possessed P50 = 27 torr, n = 2.2 (for pO2 greater than P50), Bore effect -0.4. The P50 pattern was not distinctly altered in presence of approximately 15% Met hemoglobin, while already 8% of the Met form affected the "n" parameter. Biological activity of OHb and OHb-PLP was studied.

Blood Substitutes↗
PubMedDate not supplied

[Effect of pH on the conformation properties and enzyme activity of alpha-amylase from Aspergillus terricola].

The effect of pH values on the conformation state of the protein globule and enzyme activity of alpha-amylase isolated from the culture liquid of the fungus Aspergillus terricola was studied. By the method of dispersion of optical rotation, it was demonstrated that together with the disordered structure the alpha-amylase macromolecule in its native form contained alpha-helix and beta-structures. With a pH change the enzyme macromolecule showed two conformational transformations: with a pH decrease from 4.0 to 2.0 alpha-helix uncoiled, and with a pH increase from 8.0 to 12.0 beta-form degraded. Hydrolytic activity of alpha-amylase was found to vary symbatically with the specific optic rotation in the above pH range.

Amylases↗
PubMedDate not supplied

[The role of hemoglobin affinity for oxygen in the efficiency of the respiratory function of the blood].

In acute experiments the oxygen transport properties of two solutions of modified stroma-purified hemoglobin were investigated using anesthetized Wistar rats. The solutions were: solution 1 (Hb = 8.0 g per 100 g, P50 = 12.5 mm Hg) and solution 2 (Hb = 4.4 g per 100 g, P50 = 21.5 mm Hg). The solutions were used in stage-by-stage isovolumic substitution in rats of two groups. The modified hemoglobin solution with a lower hemoglobin oxygen affinity was found to be a more efficient blood substitute. In spite of its low oxygen capacity, it could sustain life activity at very low hematocrit values. When the oxygen capacity of blood is moderate or low, hemoglobin oxygen affinity plays a very important part in oxygen supply to different tissues, specifically to the heart. The latter determines the crucial compensatory physiological reaction to acute anemia, i. e. increase of cardiac output.

Animals↗
PubMedDate not supplied

[The use of a glycomacropeptide of kappa-casein as a substrate for neuraminidase].

Glycomacropeptide from milk was studied; its molecular mass and amino acid composition were evaluated. When the glycomacropeptide was used as a substrate of neuraminidase, it exhibited many advantages as compared with ovomucin (high molecular substrate of the enzyme) due to increased content of sialic acids in the glycomacropeptide composition and to high solubility.

Amino Acids↗