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Biomedical subjects

A R Kolpakov

Publications and source records attributed to A R Kolpakov.

At least 19 recordsLinked to original sources
PubMed2005

[The clinical and pharmacokinetic features of lymphotropic therapy in patients with new-onset pulmonary tuberculosis].

Regional lymphotropic therapy used in complex treatment of patients with new-onset pulmonary tuberculosis enhances its efficiency. It is well tolerated by patients and easy-to-use. The pharmacokinetic feature of isoniazid during its lymphotropic administration is its shorter elimination half-life, decreased total clearance, and a larger area under the pharmacokinetic curve.

Adult↗
PubMed2004

Effect of long-term cold exposure on activities of cytochrome P450-containing monooxygenases and glutathione S-transferase in rat liver microsomes.

Long-term cold exposure (5 degrees C) was followed by induction of rat liver monooxygenases. We revealed an increase in activity of NADPH-cytochrome C reductase, total content of cytochrome P450 (CYP), and activities of its molecular forms CYP1A1, 1A2, 2B1/B2, 2E1, and 3A1/A2 in microsomes. These indexes reached maximum by the 10th day, but decreased with lengthening of cold exposure. Glutathione S-transferase activity decreased under these conditions. Changes in enzyme activity could be related to the increase in blood corticosterone concentration.

Animals↗
PubMed2004

[Penetration of lipoproteins and apolipoproteins of very low density into the myocardium and changes of its structure in rat heart perfusion].

The method of electron microscopy, involving extra-low density lipoproteins (ELDLP) marked by colloid gold as well as their protein components (i.e. apolipoproteins--apoELDLP), was made use of to show that they are captured by capillary endotheliocytes of the isolated perfusing rat heart. Receptor-mediated endocytosis is the main mechanism of penetration. Within 30 minutes, ELDLP interact with the capillary wall, pass through the endothelial barrier and, from the intersticium, they are captured by tissue microphages, which induces their activity. They have, on the whole, a positive effect on the intactness of muscle cells of the beating heart. During the same time span, apoELDLP remain in endotheliocytes, however, they exert a pronounced negative impact on the myocardium. The capillary endothelium, in whose cells the lysosomal apparatus activates itself and clasmatosis sets on, is affected morphologically most of all. The impairment of the capillary endothelium, development of the perivascular edema and a reduced coronary flow trigger a sequence of events leading to enhanced cytolytic processes in the myocardium due to an activated lysosomal apparatus of cells.

Animals↗
PubMed2003

[Distribution of the labeled lipoproteins in the myocardium during perfusion of the isolated rat heart and adrenaline administration].

The distribution of different classes of colloidal gold-labeled lipoproteins (LP) was studied at the ultrastructural level in rat myocardium using the isolated heart perfusion following the adrenaline stimulation. The distribution of label was examined in endotheliocytes, macrophages and in the interstitial space. The addition of adrenaline to Krebs solution during 30 min of heart perfusion in vitro was shown to increase the amount, but to decrease the velocity of penetration of labeled LP of very low and low density into the myocardium. The intensive utilization of lipid component from LP in the conditions of stimulation provides for the enhanced metabolic requirements of the cardiomyocytes and good preservation of their ultrastructure. It is possible that colloidal gold-associated protein component of LP is incorporated by the endothelium more slowly. The label penetrates into the interstitium and is accumulated in the activated macrophages. If high density LP are added together with adrenaline into the perfusion medium the label does not leave the capillary wall, while macrophages and cardiomyocytes acquire the ultrastructural features of high functional activity.

Animals↗
PubMed2002

[Penetration of lipoproteins through a capillary wall and their effects on the cardiomyocyte ultrastructure during in vitro heart perfusion].

The colloidal gold-labeled lipoprotein (LP) distribution in the myocardium after the 30 min perfusion of isolated working rat heart was studied by electron microscopy. LP of physiological concentrations are shown to be able to interact with the capillary wall and they can be incorporated by endotheliocytes. The velocity and transportation mechanisms of different classes of LP differ. Very low density LP are the most intensively taken up, low density LP enter into interstitium more rapidly than others, high density LP do not leave the capillary wall at all. The passages of labeled LP through endotheliocytes by the receptor-mediated as well as the non-receptor manners are revealed. The transportation through the widened intercellular junctions may be supposed for low density LP. For the fist time LP addendum into the perfusion medium was shown to provoke the activation of interstitial macrophages. During the perfusion duration they take inside and accumulate labeled very low density LP and low density LP in their lysosomes. The internalization may be performed by the specific endocytosis or by the simple phagocytosis. The qualitative and morphometrical analyses show that LP preserve the capillary and cardiomyocyte ultrastructure from perfusion injuries. One may suppose that there are interrelations between the capillary endothelium, the interstitial macrophages and the parenchymal cells in myocardium for realization of plasma LP effects.

Animals↗
PubMed2001

Involvement of adenine nucleotide carrier in the mechanism of the apolipoprotein C induced decrease of membrane potential in rat liver mitochondria.

Apolipoprotein C (apo C) was shown to decrease the Ca2+ capacity and membrane potential of mitochondria isolated from rat liver. The specific ligands of adenine nucleotide carrier, ADP and carboxyatractyloside (CAT), inhibited the effect of apo C on the mitochondrial membrane potential. The effect of ADP and CAT was revealed in the absence of Ca2+. We conclude that in the presence of apo C, adenine nucleosides carrier transforms into a pore, and this causes the decrease in the membrane potential of the mitochondria. ADP and CAT support the primary conformation of the carrier and therefore inhibit the effect of apolipoprotein C.

Adenosine Diphosphate↗
PubMed1999

[Effect of long-term cold exposure on apoprotein A-I, B, and E levels in the rat serum].

An increase in the quantity of triglyceride-rich VLDL as well as the total fraction VLDL and LDL occurred following the cold adaptation. The contents of apoB and apoE, respectively, increased. However, a 5-15-day exposure to cold decreased the LDL2 and apoA-1 content. In 49 days of the experiment, the LDL2 and apoA-1 content was restored.

Adaptation, Physiological↗
PubMed1995

[The role of the adenine nucleotide carrier in regulating energy and ion permeability of rat liver mitochondria upon cold exposure].

The energy state of rat liver mitochondria on day 10 of cold acclimation, when the body temperature decreases significantly concomitantly with an increase in the content of long-chain acyl-CoAs in the liver, has been studied. State 4 and uncoupling respiration rates increase in parallel; however, the integral potentials of the adenine nucleotide system in the liver diminish. In the presence of oligomycin, ADP (20 and 50 microM) decreases the II(+)-permeability and increases the Ca(2+)-capacity of mitochondria in both control and, in a lesser degree, cold-exposed rats. At 90 microM ADP has the same effect on mitochondria of both groups of rats. Carboxyatractylate abolishes the ADP effect on the mitochondria. In EGTA-containing media carboxyatractylate decreases the respiration rate in oligomycin-treated mitochondria. Palmitoyl-CoA increases the II(+)-permeability of the mitochondrial membrane and decreases the Ca(2+)-capacity of mitochondria. ADP abolished the competitive effects of this long-chain acyl-CoA. Possible involvement of the ATP/ADP antiporter in the thermoregulatory response of liver mitochondria in cold-acclimated rats and the role of fatty acids and long-chain acyl-CoAs in this process are discussed.

Acyl Coenzyme A↗
PubMed1995

[Energy status of rat liver during the dynamics of cold adaptation].

The energy state of rat liver at various times of cold acclimation has been studied. On day 10 of cold exposure, the energy state of the liver is characterized by a low level of ATP and the adenine nucleotide pool as well as by low values of the phosphorylation potential and the "energy charge". The respiratory control is decreased, while the low permeability of the inner mitochondrial membrane is increased. It is supposed that on days 10-15 after cold exposure the liver becomes actively involved in thermal stabilization. Cold acclimation on days 35-42 leads to an increase in State 3 respiration rate, respiratory control and energization of liver mitochondria. This allows to maintain the ATP level and the total adenine nucleotide pool in liver tissues at the control level. However, this does not seem to compensate completely for the energy expenditure because the phosphorylation potential and the "energy charge" of the liver are thereby decreased.

Adaptation, Physiological↗
PubMed1994

Impairment of respiratory functions in mitochondria of rats with an inherited hyperproduction of free radicals.

The functional characteristics of liver mitochondria and physical-chemical properties of mitochondrial membranes were studied in S rats with congenitally enhanced capacity to free radical generation in comparison to those in Wistar rats. It was shown previously that intense lipid peroxidation, numerous DNA rearrangements, protein oxidation, morbid states resembling human degenerative diseases and short life-span are characteristic of S rats. In present study we have demonstrated that in S rats at the age of 2-3 months the respiratory rate of the mitochondria in active metabolic state is lower than in Wistar rats, and so are the values for the respiratory control ratio, oxidative phosphorylation and membrane potential. By 10-12 months of age the decrease of the respiration rate and oxidative phosphorylation in S rat mitochondria become even more dramatic. These changes are associated with a decrease in the extent of dip of proteins into the membrane lipid layer or with the increase in the amount of protein aggregates. The results add to the understanding of the nature of morbid conditions developed under the effect of intensive free radical generation and to the comprehension of their role in aging.

Animals↗
PubMed1982

[Role of blood lipoproteins in adaptive reorganization of the rat liver mitochondria].

It was shown in experiments in vitro that high density lipids (HDL), very low density lipids (VLDL) and cAMP taken separately did not affect the kinetics of mitochondrial swelling in the liver of control and 72-hr-fasting rats. ApoHDL and particularly ApoVLDL obtained by delipidation of appropriate lipoproteins had pronounced capacities to stimulate the process of swelling. Mitochondrial swelling increased to an ever greater degree under the action of cAMP coupled with apoproteins. The maximum stimulation of the swelling was attained as a result of administering apoVLDL in conjunction with cAMP. The effects of enhanced swelling were the most remarkable in experiments with mitochondria from the control animals.

Adaptation, Physiological↗
PubMedDate not supplied

[Measurement of mitochondrial transmembrane electric potential using the fluorescent probe DSM].

The measurement of transmembrane electric potential of rat liver mitochondria was performed with fluorescent probe DSM. In the incubation medium with succinate the electric potential was -190 +/- 5 mV. Complete uncoupling caused by CCCP in the concentration 0.5 microM decreased the potential to -142 +/- 3 mV. In the partial uncoupling with a half of the mentioned CCCP concentration the potential was -158 +/- 6 mV. DSM influence on oxidation and phosphorylation was not detected.

Animals↗
PubMedDate not supplied

[Effect of apoproteins of blood lipoproteins on the functional state of rat liver mitochondria].

ApoLPHD and apoLPVLD affected the oxidative phosphorylation in mitochondria isolated from liver tissue of starved and intact rats depending on the dose administered; apoLPHD exhibited a partial effect, apo LPVLD--caused complete uncoupling of respiration and phosphorylation. Low concentrations of the both apoproteins increased the rate of mitochondrial respiration at the metabolic states 3 and 4 and did not alter the rate of phosphorylation. The additive effect was not observed after addition of dibutyryl-cAMP simultaneously with apoLPHD or with apoLPVLD into the incubation samples at low doses causing no uncoupling action. Under these conditions the effects of apoproteins prevailed. The apoproteins appear to participate in adaptive modifications of oxidative metabolism in stress-impaired liver mitochondria.

Animals↗
PubMedDate not supplied

[Mechanisms of adaptation to cold in man and animals].

The paper presents the results of studies of metabolic processes in the Arctic and Antarctic winters, members of Polar expeditions, and inhabitants of the Far North. There is a relationship between the metabolism and the length of residence in the area of low temperatures, lifestyle, and occupation. The experiments have shown changes in the phosphorylizing activity of rat hepatic mitochondria in the dynamics of cold adaptation in animals. In addition to the hormonal status and antioxidative system, serum lipoproteins were found to determine the response of the body to cold exposure. The regulatory role of the lipoprotein components apoproteins is discussed in the paper.

Adaptation, Physiological↗
PubMedDate not supplied

[Changes in the level, structure, and charges of rat serum lipoproteins during lengthy exposure to the cold].

The paper shows the results of complex investigation with the fluorescence techniques, electrophoresis a.o. methods of rat plasma lipoproteins in various terms (1 day-49 days) of cold exposure (+5 degrees C). There was the quantitative increase of the common fractions of VLDL and LDL to the 15 days of cold acclimation. The variations in percentage composition of LP occurred already on the first day. The changes of physico-chemical features of LP (surface charge and surface area, lipid viscosity and protein-lipid interactions did not always correspond to their quantitative changes and were not connected with lipid peroxidation. The decrease of the charges and the diminution of the surface area of VLDL, LDL and HDL were revealed on the first day. At 28-49 days the charges of VLDL and LDL were higher than in control, but LDL' one was lower. The occurred at this term decrease of efficiency of fluorescence energy transfer from LP' proteins to lipids, different variations of lipid viscosity demonstrated the less dip of proteins into lipids and/or the forming the aggregates of protein molecules. These in vivo LP modifications undoubtedly can induce the changes of their receptive and regulatory abilities.

Animals↗