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Biomedical subjects

A I Lukash

Publications and source records attributed to A I Lukash.

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

[Effect of non-enzymatic desamidation of gamma-globulin on its properties and biological activity].

During incubation of gamma-globulin preparations under conditions similar to physiological ones within 28 days (0.9% NaCl, pH 7.0, 37 degrees) as well as during storage at 3-10 degrees within 36 months gradual nonenzymatic deamidation of the protein occurred mainly due to hydrolysis of readily accessible amide groups (asparagine). Fluorescence of the preparations decreased gradually in the course of deamidation; it constituted for 82% of the initial value after incubation during 28 days. Immunological activity of the gamma-globulin, which lost 19.6% of amide groups, was decreased by 34%; alteration in the amidation by 45.1% was accompanied by a decrease in active antibodies concentration by 92.3%. Nonenzymatic deamidation may be responsible for conformational alterations and inactivation of gamma-globulin.

Amides↗
PubMedDate not supplied

[The effect of various chemical compounds and storage conditions on the rate of non-enzymatic deamidation of protein preparations].

The effect of different substances partly used as preservatives for the blood storage and at different stages of manufacturing of human blood preparations on the dynamics of nonenzymatic deamidation of commercial protein preparations and on their heat stability was being studied. Albumin and gamma-globulin preparations in the solutions of 60% glycerol, 60% ethylene glycol, 40% beta-alanine, aspartic and glutamic acids in physiological concentrations, 40% glucose and 40% sucrose after 2-hour thermal denaturation (100 degrees) were incubated under (or close to) physiological conditions (pH 7, 37 degrees) for 0.7; 14, 21, 28 and 90 days. The protein preparations in the saline were used as control. After precipitation of protein with TCA, the contents of free ammonia and TCA-soluble products were measured by the Lowry technique. The precipitate washed by organic solvents was used to determine the amide fractions. No reliable difference in increasing the TCA-soluble Folin-positive products was observed. All substances studied but glycerol sped up the deamidation of albumin and gamma-globulin preparations both during thermal denaturation and incubation. On the contrary, glycerol slowed down the deamidation of proteins. Possible reasons of the observed phenomena are discussed.

Deamination↗
PubMedDate not supplied

[Use of blood biochemical parameters for evaluating the clinical effectiveness of hyperbaric oxygenation therapy].

Changes in the total peroxidase activity (TPA) and extraerythrocyte hemoglobin (EEH) content have been studied in the blood plasma and serum of patients treated with hyperbaric oxygenation (HBO). TPA and EEH content after the 3rd HBO session increased by 38% and 257%, respectively, in the plasma and by 56% and 74%, respectively, in the serum. By the end of HBO therapy course, after the 8th session, plasma level of the parameters under study normalized, while their serum level was higher than baseline. Possible use of the parameters under study for the assessment of HBO efficacy is discussed.

Hematologic Tests↗
PubMedDate not supplied

[Effect of starvation on the intensity of proteolysis and amidation of proteins in tissues of rats of different ages].

Rates of autolysis and degree of amidation of tissue proteins were studied in rats under conditions of ageing and after starvation during 7 days. Proteins with decreased content of amide groups accumulated in brain, liver tissues and skeletal muscles. This phenomenon occurred apparently due to decrease in the rate of protein autolysis observed in ageing. In testes, where the rate of protein autolysis was similar both in young and old animals, the protein amidation was not altered on the course of ageing. Under conditions of severe starvation activation of proteolysis was observed in cells. At the same time, the amide content was restored in liver and muscle proteins of old rats up to the level, estimated in tissues of young animals. These data suggest stimulation of selective degradation of the deamidated proteins. The activation of autolysis and normalization of the protein amide groups content were not observed in brain of old animals under conditions of starvation.

Aging↗
PubMedDate not supplied

[Amidation of blood proteins during hyperglycemia in experimental diabetes mellitus].

Rates of amidation of blood serum albumin and hemoglobin was studied in hyperglycemia developed during alloxan diabetes mellitus. Content of glucose in blood of the animals with diabetes exceeded 5.2-fold its level in blood of controls; amount of glycosylated hemoglobin was increased by 41.7%. Concentration of total, readily and hardly hydrolyzed amide groups was decreased in hemoglobin of the impaired animals by 13.1%, 17.6% and 10.4%, respectively, as compared with control group. The degree of blood serum albumin amidation was not altered. Hyperglycemia, accompanied by glycosylation of proteins, was the most probable cause of accelerated deamidation of hemoglobin. Participation of the protein deamidation in pathogenesis of diabetes mellitus is discussed.

Amides↗
PubMedDate not supplied

[Degradation of deamidated proteins by tissue proteinases].

The rate of native and deamidized serum albumin in vitro splitting by the brain, liver, kidney, testicle and spleen tissue proteinases was studied at pH 3.2, 4.8, 7.2 and 8.5. The deamidized preparation of serum albumin was obtained during its incubation under sterile conditions at 37 degrees C. The amount of amide groups in the process of protein incubation decreased by 19.4% mainly due to readily hydrolyzed asparagine groups. Desamidated serum albumin is splitted by tissue proteinases more intensively than native albumin. Intensity of the splitting depends on pH of the incubation medium and proteinase source. Specific proteolytic activity to desamidated serum albumin is shown to decrease in old rats as compared to young ones.

Animals↗
PubMedDate not supplied

[Biochemical estimation of individual sensitivity to oxygen intoxication in rabbits].

Correlation between a pro-oxidant activity of blood, estimated by means of chemoluminescence in the system H2O2-luminol-blood plasma, and individual sensitivity of rabbits to the effect of oxygen was studied. Alterations in the blood pro-oxidant activity, as shown by treatment of the blood sample with 0.7 MPa of oxygen in vitro, correlated distinctly with the period of convulsions as well as with viability of animals during acute hyperoxia.

Animals↗
PubMedDate not supplied

[Participation of iron ions in antioxidant action of urea].

The in vitro and in vivo experiments show that urea inhibits the bivalent iron oxidation and as a result inhibits the lipids peroxide oxidation in homogenates of the brain and liver tissues and in suspension of rat erythrocytes.

Animals↗
PubMedDate not supplied

[Spontaneous deamidation of gamma-globulin].

gamma-Globulin from human blood serum was incubated in thermostat at 37 degrees within 15, 30, 45, 60 and 72 days. Amount of readily and poorly hydrolyzed amide groups as well as an increase in amino acid content were estimated in the protein at zero time and at these periods. The sterility of the preparation was examined in each case. Spontaneous deamidation of gamma-globulin, observed during incubation, caused an increase in negative charge and altered electrophoretic mobility of the protein molecule. gamma-Globulin was attacked by prothelin more effectively as amount of amide groups was decreased in the protein. Spontaneous deamidation appears to be one of reasons of the protein molecules ageing.

Amides↗
PubMedDate not supplied

[The effect of pyrazidole on the middle molecule level during various modes of hypobaric hypoxia].

Content of middle mass molecules (MMM) was studied in blood plasma of rats treated with pyrazidol, the known inhibitor of monoamine oxidase of the A type. A distinct increase in the MMM nonpeptide component was detected both in intact animals and in the rats kept under hypoxic conditions (9,000 m, 3 hrs) after three administrations of pyrazidol. Under conditions of intermittent hypoxia higher increase of the nonpeptide component as well as an increase of the MMM peptide component were detected. The MMM blood fraction was also elevated in the animals adapted to hypoxia. A possible role of the MMM fraction in the pyrazidol-produced adaptation effect during hypoxia is discussed.

Adaptation, Physiological↗
PubMedDate not supplied

[Chemiluminescent analysis and some indicators of nitrogen catabolism in rat blood plasma in hypoxia with subsequent hyperoxia].

Different regimens of oxygenation were studied in rats: acute hypoxia (9,000 m, 3 hrs), acute hyperoxia (0.7 MPa O2), which caused convulsions, and their simultaneous effects. Under these conditions the following parameters were evaluated: the rate of Fe(2+)-induced chemiluminescence, content of nitrogen and peptide catabolism products (urea, urates and middle molecule peptides) as well as total peroxidase activity, content of extraerythrocyte hemoglobin and lactic acid in blood plasma. Distinct inhibition of the chemiluminescence rate was found in all the three experimental groups studied; accumulation of uric acid, middle mass peptides, extraerythrocyte hemoglobin, lactic acid as well as an increase in the total peroxidase activity were observed in hyperoxia and in simultaneous effect of hypo- and hyperoxia; total peroxidase activity was decreased in rats with acute hypoxia. Accumulation of urates and middle mass peptides was considered according to these substances capacity to inhibit free radical oxidation in vivo.

Animals↗
PubMedDate not supplied

[Emoxipin correction of disorders of lipid peroxidation as affected by a slight excess of oxygen pressure].

The role of the emoxipin (Em.) (2-ethyl-6-methyl-3-oxipyridine) in the correction of the free radical oxidation and allied processes in lung tissues and blood plasma under high-pressure oxygen-prolonged action has been investigated. The studied oxygen exposure (0.3 MPa, 5h) causes the lung stage of oxygen intoxication. It is confirmed by exterior morphological assessment of the lung. The lipid peroxidation increase in lung tissue and blood plasma as well as erythrocyte membranes destabilization result from oxygen exposure. Lipid peroxidation intensity was estimated by determining of content of lipid peroxidation molecular products such as diene conjugates and Shiffs' bases. Erythrocyte membranes stability was evaluated with hemoglobin yield, total iron level and total peroxidase activity in blood plasma. Emoxipin was injected intraperitoneally in a dose 150 mg per 1 kg rats' weight just before the oxygen exposure. Emoxipin is found to improve physiological state of animals and to increase their survival; it normalizes morphology of the lungs and their state; stabilizes erythrocyte membranes injured under oxygen exposure; decreases intensity of lipid peroxidation processes in the lungs and in blood plasma which was previously increased under hyperoxia.

Animals↗