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Biomedical subjects

V V Davydov

Publications and source records attributed to V V Davydov.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

[Lipid peroxidation in adult and aged rat heart under immobilization stress].

Lipid peroxidation (LPO) in the heart of adult (10-12 month) and old (22-25 month) Wistar male rats was investigated during immobilized stress. Immobilization of rats was accompanied by increasing the concentration of all studied LPO intermediates in the myocardium of both age groups. Accumulation of LPO products in old rat hearts was considerably higher than in adult ones. Dimethyl sulfoxide injection limited stress-induced stimulation of LPO. There were age related variations in efficiency of this antioxidant effect on the heart during immobilized stress.

Aging↗
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[The effect of malonate on lipid biosynthesis in the liver].

Malonate regulates the liver metabolism and promotes stimulation of the fatty acids synthesis and pyruvate oxidation inhibition. The latter is particularly significant in regulation of aerobic processes and responsible for antihypoxic action of malonate.

Animals↗
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[The content of pyridine coenzymes in the liver of the adult and old rats in stress].

The concentration of oxidized and reduced NAD and NADP in the liver was studied in 36 adult (10-12 month old) and old (22-25 month old) male Wistar rats exposed to immobilization stress. It was established that content of piridine coenzymes in rat liver does not change with age. Immobilization stress decreases NADP reduction in adult animals, increases percentage of NADN in the total pool of reduced piridine coenzymes in the liver. In old stressed rats reduction of the NADP pool diminished accompanied by a distinct lowering of concentration of reduced NAD compared to its level in adult animals. It is suggested that shifts in the system of piridine coenzymes in the liver of adult rats support maintenance of effective function of the microsomal oxigenase chain in stress, in old animals promotes stress attenuation.

Age Factors↗
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[Total intravenous anesthesia with ketamine and the condition of the higher psychic function in the early and remote postoperative periods].

Influence of total intravenous anesthesia with ketamine on the higher psychic function was studied, immediately after surgery and in the remote postoperative period, in 143 patients with different typological properties of the nervous system after a scheduled surgery--supravaginal uterectomy in fibromyoma of the uterine body. The authors defined 6 groups of patients with different typological properties of the nervous system. Persistent impairment of the higher nervous functions were established, immediately after surgery and in the remote postoperative period, in patients with a weak nervous system, biased nervous balance towards excitation, and with lability of nervous processes. Total intravenous anesthesia with ketamine, when used in patients with the robust nervous system, biased nervous balance towards excitation, and with lability of nervous processes, caused changes in the higher nervous functions and an intensified level of nervous-and-psychic loads, which were unstable and were arrested by the 30th postoperative day. The use of such anesthetic scheme was found to be inadvisable in the above groups of patients. The described impairments were not registered when total intravenous anesthesia was used in patients with a balanced nervous system irrespective of its type, a biased nervous balance towards inhibition and with inertness of nervous processes. The above anesthetic management is acceptable for such patients.

Adult↗
PubMedDate not supplied

[Age-specific changes of carbohydrate metabolism in rat liver in immobilization stress].

We have studied peculiarities of the main pathways of glucose utilization in the liver of adult and old rats under immobilization stress. Our data indicate that in both adult and old rats stress is accompanied by an increase in glycolysis intensity in the liver. In stressed adult rats stimulation of glycolysis is associated with metabolism changes characteristic of decreased oxidative decarboxylation of pyruvate in the liver. In immobilized old rats glycolysis stimulation took place in maintanence of effective oxidation of pyruvic acid and enhancement of glucose catabolism in pentose phosphate pathway.

Aging↗
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[Adenine nucleotide system in adult and old rat liver during immobilization stress].

Adenine nucleotide and inorganic phosphate concentrations were studied in livers of adult (10-12 month) and old (22-25 month) Wistar male rats during immobilization stress. Study revealed that level of liver energy provision supply of old rats was lower than in adults. Stress caused reduction of adenine nucleotide concentration in the liver of both adult and old animals.

Adenosine Diphosphate↗
PubMedDate not supplied

[Peculiarities of pH influence on aldehyde reductase activity in the liver of rats from different age groups subject to immobilization stress].

In order to develop the notions about the causes of age-dependent changes in the organism resistance to the influence of damaging stress factors the study of aldehyde reductase activity manifestations was carried out in the liver of 1.5-, 2-, 6-, 12-, 24-months-old rats subject to immobilization stress with different values of pH of reactive mixture. It has been shown that the immobilization stress is accompanied by the shift of the enzyme pH-optimum to the acid side. This change manifestation in 1.5-months-old and 24-months-old animals has been less significant as compared with that in the rats of other age groups.

Aging↗
PubMedDate not supplied

[Age-related characteristics of changes in aldehyde reductase activity in the skeletal muscle of rats during immobilization stress].

A study of peculiarities of aldehyde reductase (AR) activity changes in the skeletal muscle from 1.5-, 2-, 6-, 12-, 24-months old rats during immobilization stress has been carried out. It has been shown that 6- and 24-month old rats demonstrate the highest sensitivity to influence of prooxidant factors of immobilization stress. This included accumulation of conjugated dienes and Shiff bases in the muscle cells 30 minutes after the immobilization of animals from investigated age groups. These changes have been accompanied by activation of AR in 6-months old rats, however, the 24-months old rats have not shown changes in the enzyme activity. It is suggested that that age-dependent activity changes in AR-activity are one of the causes underlying different sensitivity of muscle cells to the conditions of oxidative stress which is formed during immobilization at different ontogenesis stages.

Aging↗
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[Metabolism of free malonic acid in rat tissues].

It is found that the liver skeletal muscle and brain utilize free malonic acid in lipogenesis reactions with different rate. It is shown that the inclusion of malonic acid to lipid biosynthesis is connected with its decarboxylation by the first carbon atom, with the next condensation of the formed intermediate with coenzyme A and further transformations of acetyl-coenzyme A.

Acetyl Coenzyme A↗
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[Changes in the levels of somatotropin and cyclic nucleotides and the state of protein metabolism in the brain and myocardium during stress as well as in myocardial necrosis following stress].

Stress itself as well as the subsequent myocardium necrosis developed after stress were mainly responsible for distinct decrease in concentration of somatotropin, somatomedin and for impairments in protein synthesis accompanied by decrease in proteins half-life in brain hemispheres and in non-ischemized heart left ventricle.

Animals↗
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[Efficacy of ginseng drugs in experimental insulin-dependent diabetes and toxic hepatitis].

Drugs obtained from the roots and leaves of plantation ginseng and ginseng root tissue culture displayed a high antidiabetic and hepatoprotective activity in experiments on mice and rats. In alloxan diabetes these adaptogenic phyto-agents prevented alloxan-induced activation of processes of lipid peroxidation in the pancreas and demonstrated definite insulinogenic properties: they increased the basal content of insulin in blood and the glucose-dependent secretion of this hormone. In CCl4 acute toxic hepatitis the studies ginseng drugs reduced the disorders of hepatic detoxification and glycogen-synthesizing functions.

Animals↗
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[The action of adaptogenic plant preparations in experimental alloxan diabetes].

Experiments on mice and rats with alloxan diabetes were conducted for comparative assessment of the effectiveness of therapeutic use of adaptogenic plant pharmaceuticals as well as some other commonly used plant drugs. Of marked antidiabetic properties were root and leaf ginseng tincture (LGT), Echinopanax tincture, extracts of Eleutherococcus, Rhodiola (ER) and Leuzia which decreased the blood level of glucose in a CTT (5 g h of glucose per I kg of the animal body mass) from 17.15 to 11.19, 11.50, 12.72, 11.69, 13.47 mmol/l and increased the alloxan-reduced level of liver glycogen by 50-80% (P less than 0.05). Aralia and Schizandra tinctures for this diabetic model were ineffective. Yarrow, everlastings and birch leaf tea also possessed marked hypoglycemic and glycogen sparing properties. The most effective experimentally plant adaptogens LGT and ER increased the blood level of insulin in alloxan diabetic rats in a GTT from 16.75 up to 44.42, 35.31 microU/ml and decreased the level of glucagon from 495 to 195 and 138 pg/ml, respectively. The authors discussed mechanisms of antidiabetic, insulinotropic and hypoglucagonemic action of the effective plant pharmaceuticals and the prospects of their use in multimodality therapy of diabetes mellitus of type I.

Adaptation, Physiological↗
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[NADH-vanadate-oxidoreductase in emotional-pain stress and its possible role in the regulation of Na+-K+-ATPase activity].

It is established that NADH-vanadate-oxidoreductase in brain and heart changes its activity depending on the period of the emotional pain stress (EPS) development. In early acute period of EPS (to 48 hours) NADH-vanadate-oxidoreductase is activated in the brain, while in the heart its activity lowers in comparison with normal animals. In the later period after EPS the stimulation of NADH-vanadate-oxidoreductase activity in the both organs in observed. This dynamics creates possibilities for different accumulation of such Na+,K+-ATPase inhibitor as vanadate (VO3-) in the heart and brain. An increase of pO2 of the blood, probably, influences the enhancement of the VO3- concentration in the blood and organs.

Animals↗
PubMedDate not supplied

[The adenylic system in the brain structures of rats with experimental myocardial infarct].

In rats experimental myocardial infarction, whether it was reproduced after a preliminary stress or in its absence, a reduction was found of ATP content initially appearing in the neocortex at the second day of the experiment. The deficit of providing of the energy in brain structures in a traditional variant of infarction reproduction increased still greater, and in the case of preliminary stressing the ATP content was reduced. Parallelly a characteristic change took place in the concentration of products of the fermentative ATP hydrolysis in the brain structures.

Adenine Nucleotides↗
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[Blood insulin and characteristics of nitrogen metabolism in organs during myocardial necrosis developing after emotional stress].

Simulation of myocardium necrosis developed after emotional stress led to hyperinsulinemia and hyperglycemia simultaneously with a decrease in arterial-venous difference of oxygen. In control, stress-treated animals, hypoinsulinemia and hyperglycemia were detected. Dissimilar alterations in nitrogen metabolism were observed in heart and brain tissues of the animals with myocardium necrosis under conditions of anomalous insulin secretion and glucose consumption. During the first steps of myocardium necrosis after emotional stress increase in content of nucleic acids, ammonium, urea as well as activation of leucine aminopeptidase were found in heart of the animals. At the same time, a number of compensatory reactions, involved in nitrogen metabolism, were not found in brain of the animals with myocardium necrosis; distinct activation of leucine aminopeptidase was detected in the tissue.

Animals↗
PubMedDate not supplied

[Oxidative phosphorylation in the brain in myocardial necrosis. The effect of emotional stress].

The formation of ischemic myocardium necrosis is accompanied by a disturbance of respiratory and phosphorylating function in the cortex of cerebral hemispheres. In this case the most considerable changes are revealed with the use of alpha-ketoglutarate as an oxidation substrate. Inhibition of succinic acid oxidation arises only when the acute stage of the experiment comes to an end (by the 7th day). Development of ischemic myocardium necrosis after the endured stress results in deeper inhibition of mitochondrial respiration of cerebral hemispheres.

Animals↗