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Biomedical subjects

A I Bozhkov

Publications and source records attributed to A I Bozhkov.

At least 19 recordsLinked to original sources
PubMed2006

[The growth constraining diet causes various strategy of adaptation in young and adult animals].

The glucose-6-phosphatase activity of microsomes and phosphorylative mitochondrial activity of liver cells, alanine- and aspartate aminotransferase activities in plasma of blood of young (3 month) and adult (21 month) male rats kept under three various diets resulting in a various degree of a growth inhibition and losses of weight of a body have been studied. There were selected diets giving to animals the food full-valued by composition but limited by quantity. Experiment proceeded 50 days. It was found out various metabolic strategy of adaptation in young and adult animals in reply to this influence. Experimentally this phenomenon revealed itself in various correlations between researched metabolic parameters at young and adult rats. Activity of researched enzymes in adult animals changed in a greater degree in comparison with a base level than at young ones. Researchers suppose that the revealed distinctions of metabolic strategy of adaptation in young and adult animals can be attributed to their generated epigenotypes.

Adaptation, Physiological↗
PubMed2004

[Does the liver ability to regeneration decrease with age? The dynamics of functional activity of mitochondria in process of the liver regeneration].

The ability of liver of 1-, 3-, 12- and 24-month rats to mass restoration, mass gain and activity of cell energy system from 1 to 30 days after ectomy of liver medial and left lateral lowels were investigated. It was shown that the old animals did not rebate to young ones in respect of regenerant gain and exceeded them with mitochondria functional activity at the early stages of regeneration (2-24 h after operation). We detected a little lag in old rats (12 and 24 monthes) in comparison with 1-3 ones in rate of liver mass reset to corresponding age groups control level. It may be explained by the difference between young and old animals in strategy of organism homeostasis after ectomy of 2/3 liver mass. The rhythmic character of activities for the most of indices of mitochondria functional activity in liver regenerating up to 24 h with maximum at 2-3 h and 12-18 h after operation was detected. The detected rhythm was typical mostly to mitochondria of the old animals. The high functional activity of mitochondria of the old animals and on the late stages of liver regeneration was shown.

Adenosine Diphosphate↗
PubMed2001

[A low-calories diet as a model of life span expansion and study of mechanisms of aging].

The model of experimental augmentation of life expectancy animal with the help of a low-calorie diet designed empirically more 50-[symbol: see text] of years back. The translation animal on such diet is accompanied by development of stress--response and the further adaptation to restricted power supply. As a result of it occurs complex change in all metabolic systems of an organism (energy system of a cell, endocrine, immune system, system of toxicity release, connecting tissue, activity genetic and system which synthesizes an protein). The orientation of these changes provides retardation of development, delay of formation age-dependent of pathologies, and as the consequence, augmentation average life and, that is especially important, maximal life expectancy. The effect of augmentation of life expectancy at use of low-calorie diets depends on quantitative restriction of a calorific within the framework of 40-75%, sex and genotype animal, age animal at the moment of translation on a diet. The proposition expresses, that the prolongation of life at use to a low-calorie diet can be surveyed as specific response of some organisms in a population (not everything, the part animal perishes in a start of experiment) on such stressful action as restriction of nutrition.

Age Factors↗
PubMed1997

Three dose-dependent stages of the effect of copper ions on functional activity of biological systems.

The dose-dependent effects of copper sulfate on the proliferation and functional activity of the genome of liver cells and of algae in vivo and the activity of RNA-polymerase and glucose-6-phosphatase and formation of malonic dialdehyde in vitro were investigated. Administration of various doses of copper sulfate causes a dose-dependent three-phase response of biological systems comprising a stimulation phase, a latent phase, and a phase of inhibition. The degree of manifestation of the three-phase response depends on the functional activity of the biological system. The consecutive dose-dependent binding of metal ions with components of cells forms the basis of the three-phase response to copper ions.

Animals↗
PubMed1997

Mechanism of induced resistance to protein inhibitors of proliferation.

A 12 kD protein (IHP-12) was isolated from the cytosol of liver cells; IHP-12 inhibited proliferation of the liver cells by 50% when injected at 2.5 mg/100 g animal weight. Repeated injections of IHP-12 induced resistance of the liver cells to its anti-proliferative effect. After intraperitoneal injection, IHP-12 is localized in the cytosol and to a lesser extent, in cell nuclei. IHP-12 is degraded in the cytosol but in nuclei it retained its native structure for at least 8 h. The mechanism of induced resistance to IHP-12 was not related to a change in cell binding of IHP-12, its distribution in cellular compartments, and intracellular metabolism. The induced resistance may be associated with a change in the direction of IHP-12 activity, i.e., change in its function in the animal.

Animals↗
PubMed1995

[The effect of a chalone-containing fraction on passage of the S-phase of the cell cycle in regenerating liver].

The duration and reversibility of the liver chalone-containing fraction on DNA synthesis in regenerating liver cells have been studied. It has been shown that administration of the [14C] chalone-containing fraction results in a rapid specific binding of the label to liver cells in which the label is retained for no less than 12 hours. The specific radioactivity of DNA in regenerating liver cells decreases 3-4-fold irrespective of the time of administration of the [14C] chalone-containing fraction. After repeated injections of the fraction under study, the hepatocytes loss their sensitivity towards this fraction. It is suggested that chalones exclude some part of the hepatocytes from the cell cycle which, in turn, leads to the asynchronous involvement in the cell cycle of a new hepatocyte population which is resistant to the chalone action.

Animals↗
PubMed1995

[Accumulation of lipids in hepatocyte cytosol after local hyperthermia and partial hepatectomy].

The effects of local hyperthermia and partial hepatectomy of the liver as well as of copper ions on the lipid content in liver cell cytosol and microsomes and in blood serum have been studied. It has been found that these effects provoke significant changes in the lipid content of the cytosol and, particularly, of triacylglycerides. Within one hour after partial hepatectomy the lipid content in the liver cytosol increases 2-fold, while by the moment of completion of the regenerative process (day 8th) it decreases sharply--down to 18.7 micrograms per mg of cytosolic protein, being several times lower in comparison with the control level. The results obtained are discussed in terms of the lipid response to stress.

Animals↗
PubMed1992

[Lipid metabolism and structure-activity features of the endoplasmic reticulum membrane in regenerating rat liver].

The relationship between the neutral lipid and phospholipid metabolism and some structure-function peculiarities of regenerating rat liver endoplasmic reticulum membranes (13 hours after surgery, i.e., corresponding to the G1-period of the cell cycle) was studied. There was an increase in the degree of the endoplasmic reticulum membrane development and the nonesterified fatty acid (NFA) and triglyceride (TG) content in regenerating rat liver microsomes. The relative specific radioactivity of neutral lipid and phospholipid fractions in regenerating rat liver microsomes was lower than in control animals, presumably due to the high rate of the microsomal lipid exchange in the regenerating liver with other cell organelles. The changes in the lipid content and rate of their metabolism in the regenerating rat liver were associated with the increase in the membrane microviscosity and the decrease in the activity of the membrane-bound enzyme (glucose-6-phosphatase). The differences in the time-dependent changes in the synthesis and metabolism of lipids in the NFA and TG fractions may be regarded as an endogenous factor determining the structure-function peculiarities of endoplasmic reticulum membranes.

Animals↗
PubMed1991

[The effect of copper and insulin on nucleic acid and protein synthesis in Tetrahymena pyriformis cells under different functional conditions].

The effect of copper ions and insulin on the rate of DNA, RNA and protein synthesis, and on the growth dynamics of Tetrahymena pyriformis cells, and also joint action of Cu2+ and insulin on these processes has been investigated. The effect of Cu2+ after 6-fold action of heat shock (34 degrees C) on the cell culture has been studied. The results obtained indicate that significant reconstructions of the infusoria cell functioning conditions caused by various reasons re of great importance in the adaptation mechanisms to such stress factors as heavy metals.

Animals↗
PubMed1980

[Some peculiarities of gene expression in inbred and hybrid rats under normal conditions and after partial hepatectomy].

The peculiarities of gene expression in line and hybrid rats in the normalcy and after partial hepatectomy were studied. It was shown that the relationship between the RNA synthesis rate in chromatin and RNA transport in the cytoplasm as well as the correlation between the RNA transport rate and the activity of the protein-synthesizing mechanism vary in animals with different genotypes. After partial hepatectomy the hybrids have their S-period of the cell cycle earlier than the line animals. The hybrids do not differ from the parental forms in the rate of RNA chromatin synthesis; however, the newly synthesized RNA of the hybrids in transported into the cytoplasm 5.7 and 5 times faster than that of the lines Vistar and August. The rapidly transported RNA of hybrids is likely to have a more prolonged life as compared to the line animals. After partial hepatectomy an activation of the whole gene expression system occurs. The differences in the gene expression system of hepatocytes of inbred and hybrid animals in the regenerating liver become less pronounced.

Animals↗
PubMedDate not supplied

[Pharmacokinetics of lipophen--a novel combined phospholipid liver protective agent of natural origin].

Study of the labeled lipophen distribution in organs and tissues of experimental animals showed evidence of a nonlinear drug pharmacokinetics. The maximum amount of labeled lipophen accumulated in liver, spleen, and kidneys, while the drug content in heart, muscles, and brain was very small. The products of lipophen metabolism are excreted with both urine and feces.

Administration, Oral↗
PubMedDate not supplied

[Effect of combination of high-voltage pulses and other physical factors on the intensity of reproduction of Anabaena flos aquae].

It was shown that the influence of high-voltage pulses (intensity of electric field 40-120 kV/cm) on cyanobacteria Anabaena flos aquae can be different and depends on the mode of treatment. It was found that in the range of pulse durations less than 1 microsecond with a pulse repetition rate of up to 500 Hz, and final temperature in the working chamber (60 +/- 1) degree C, a gradual full and irreversible inactivation of cyanobacteria independent of the pulse shape takes place. At the same time, a rapid (but slower than by the action of high-voltage pulses) heating without treatment with high-voltage impulses at the same final temperature leads to an inactivation of 80% of initial cyanobacteria followed by growth of bacteria up to 700% and more.

Cyanobacteria↗
PubMedDate not supplied

[Effect of human fetal liver cells on the rate of DNA and nRNA synthesis in regenerating rat liver].

The model of partial hepatectomy was utilized to investigate the influence of human fetal liver cells (FLCs) and of human embryo tissue (PCF) postnuclear cytoplasm fraction injection on the rate of DNA and nRNA synthesis in regenerating rat liver cells. Single infusion of FLCs and PCF into the spleen pulp of rats has been shown to increase the DNA synthesis 24 hours after the operation in 2.5 +/- 0.4 and 3.2 +/- 0.5 times respectively. A group of rats has been identified with no influence of the infusion on the DNA synthesis 24 hours after partial hepatectomy, this process having been even retarding in 48 hours after the operation. Meanwhile the FLCs and PCF infusion enhanced the intensity of nRNA synthesis in 72 hours after the operation in all the animal groups. The effect demonstrated is probably caused by the biologically active substances contained in the fetal tissues.

Animals↗
PubMedDate not supplied

[Metabolism of endogenous aldehydes: participation in oxidative stress-induced lesions and its age aspects].

This review summarizes the data regarding the synthesis and utilization of endogenous aldehydes and mechanisms of their cytotoxic effect. Peroxidation of polyunsaturated fatty acids is the main source of endogenous aldehydes. There are many different aldehydes generated in the cell. The most abundant is 4-hydroxy-2,3-nonenal synthesized from linoleic acid. Aldehydes may react with proteins and nucleic acids and change their functional properties. Aldehyde utilization mainly occurs in reactions catalysed by aldehyde dehydrogenase, aldehyde reductase and glutathione-S-transferase. The major pathway of their catabolism is accompanied with their conjugation with glutathione. Endogenous aldehyde utilization has its tissue- and age-dependent specificity. The status of aldehyde catabolism can modulate free radical alteration effect on the cell. An adequate stimulation of endogenous aldehyde utilization in the situation of enhancement of free radical generation may promote increasing the cell resistance to oxidative stress injury. Senescence is accompanied by a decrease in endogenous aldehyde utilization intensity in tissues. This could be important in the pathogenesis of age-dependent pathology.

Aging↗