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Biomedical subjects

A D Nozdrachev

Publications and source records attributed to A D Nozdrachev.

At least 19 recordsLinked to original sources
PubMed2006

The role of defensin NP-1 in restoring the functions of an injured nerve trunk.

This report presents results from studies on the actions of neutrophil defensin NP-1 on the initial stage of regeneration of the lesioned sciatic nerve in rats. The effects of defensin on the growth rate and functional characteristics of regenerating nerve fibers were assessed by recording total action potentials 21 days after transection and microsurgical suturing of the nerve. These experiments showed that defensin increased the rate of growth of regenerating nerve fibers by 30%: the distance over which nerve spike conductivity was restored in the lesioned nerve increased from 7.2 +/- 1.2 (control) to 10.5 +/- 0.8 mm (experiment) from the suturing site (p < 0.05). In addition, an increase in the excitation conduction rate along the regenerating nerve fibers by 20% compared with control was observed. Overall, the results provide evidence for the positive effects of defensin on restoration of the functions of the lesioned nerve trunk.

Animals↗
PubMed2006

[Rhythmical electrical activity in the cat stellate ganglion during postnatal ontogenesis].

Electrical activity of the stellate ganglion was studied in newborn, 10-, 20-, 30-day-old, two- and six-month-old kittens using the spectral analysis. The development of sympathetic activity patterns was different during ontogenesis. The amplitude of discharges increased from the period of birth until the second month of kittens' life. In newborn and 10-day-old kittens, synchronous discharges of postganglionic fibers were represented by slow and low frequency impulses with frequencies of breathing and heart rate. ppears in 20-day-old kittens. The formation of the sympathetic discharge patterns ends at the second month of animals life.

Action Potentials↗
PubMed2006

[The age specifics of the neurotransmitter composition of the stellate ganglion neurons].

The stellate ganglion neurons' transmitter composition in the rat siblings of different age (newborn, 10-, 20-, 30-, 60-day old) revealed that the greatest amount of the neurons in all the rats contained thyrosinhydroxylase. Most cholinacetyltransferasepositive. In 30- and 60-day old rats, just a few cells contained both above enzymes. Since birth, the percentage of cells containing thyrosinhydroxylase and neuropeptide Y has been growing. Along with that, the share of somatostatin-positive neurons was decreasing. The percentage of the VIP-positive cells and the neurons containing cholinacetyltransferase was increasing until the 10th day of life and then dropped again. The somatostatin-positive neurons in all the rat siblings were represented by small cells, whereas the neurons containing cholinacetyltransferase were represented by large cells. The maturation of the neurotransmitter set in the rat stellate ganglion terminates by the end of the second month of life.

Acetylcholinesterase↗
PubMed2005

Glycolysis and oxidtion enzyme activity in rat brain during insulin-induced hypoglycemia against the background of alloxan-induced diabetes mellitus.

Insulin-induced hypoglycemic coma in animals with alloxan diabetes was observed at a higher basal glucose level in the blood compared to healthy animals. It was associated with inhibition of glycolysis and glycogenolysis and decreased activities of succinate dehydrogenase and glutamate dehydrogenase in the cerebral hemispheres and brainstem.

Alloxan↗
PubMed2005

[Defensin NP-1 in restoration of the injured nerve trunk functions].

The effect of Defensin NP-1 on early phase of injured sciatic nerve regeneration was studied in rats. Using the technique of AP compound recording performed within 21 days after the nerve trunk cutting with subsequent microsurgical nerve suture, the rate of fibres growth was shown to increase by 30% following Defensin treatment: the distance to which the nerve impulse conductivity through injured nerve fibres was restored has extended from 7.22 +/- 1.2 mm (control) to 10.5 +/- 0.8 mm (Defensin treatment) from the suture site (p < 0.05). Moreover, the conducting capacity of the regenerating nerve fibres has risen by 20% as compared with control values. The findings suggest a positive effect of Defensin on restoration of injured peripheral nerve in rats.

Action Potentials↗
PubMed2004

Recovery of mechanoreception at the initial stage of regeneration of injured sciatic nerve in rats in conditions of central axotomy of sensory neurons.

The ability of injured afferents of the rat sciatic nerve to regenerate in conditions of damage to their connections with the central nervous system (CNS) as a result of extensive rhizotomy was studied. Recording of spike activity from single nerve fibers demonstrated that rhizotomy, performed simultaneously with nerve injury, had virtually no effect on the initiation of regenerative processes in sensory nerve fibers. The first clear signs of reinnervation of the skin of the foot by decentralized nerve fibers was seen 30 days after nerve injury, which agrees with data obtained in standard conditions, i.e., without rhizotomy. Decentralization of sensory neurons was found to lead to increases in the threshold of perception of a mechanical stimulus in intact and regenerating receptors. However, regenerating receptors showed a significantly more marked decrease in stimulus sensitivity.

Animals↗
PubMed2003

Role of the dopaminergic system of the brain in the effects of glucocorticoid hormones.

The conditioned reinforcement properties of the synthetic glucocorticoid dexamethasone and the possible mechanisms of its action were studied using a conditioned place preference response. On test day 1, male Wistar rats were placed in a two-chamber apparatus and the time spent in each sector was measured for 10 min. Over the next six days, combinations of one of the chambers with administration of agents (reinforcement) were presented using injections of dexamethasone in one sector and injections of physiological saline in the other sector on alternate days. After combinations of dexamethasone (0.25-0.77 mg/kg, i.p.) with the non-preferred sector, rats showed dose-dependent place preference on test day 2; however, when dexamethasone was combined with the initially preferred sector, animals given dexamethasone at a dose of 0.75 mg/kg showed only a slight level of place avoidance. Subthreshold doses of phenamine (0.25 mg/kg) given alone had no effect; however, when given on a background of dexamethasone (0.25 mg/kg), phenamine evoked a place preference response in rats lacking an initial place preference for one sector. Administration of dexamethasone alone (0.25 mg/kg) in these conditions did not induce place preference. Administration of the dopamine D2 receptor antagonist sulpiride (20 mg/kg) 30 min before combinations of dexamethasone (0.25 mg/kg) with the non-preferred sector completely prevented the acquisition of place preference. Administration of the D1 dopamine receptor antagonist SCH23390 (0.05 mg/kg) had no effect on the acquisition of conditioned preference. These results provide evidence for the involvement of D2 receptors in conditioned place preference induced by dexamethasone.

Amphetamine↗
PubMed2003

The effects of epiphyseal peptides on the release of immunoglobulins in Peyer's patches in rats in vitro.

The effects of epiphyseal peptides (1 microg/ml) on the release of immunoglobulins into the incubation medium by isolated Peyer's patches from non-immunized mice and mice immunized orally against ovalbumin were studied during 40-min incubations. The possibility that epiphyseal peptides act on adrenoreceptors of cells in secondary lymphoid organs in the small intestine was assessed using alpha- and beta-adrenoreceptor blockers, i.e., phentolamine HCl (0.02 mg/ml) and anaprilin (0.06 mg/ml) respectively. Basal levels of secretory activity in control Peyer's patches from immunized rats were 2.4 times (p < 0.01) greater than for the lymphoid organs of non-immunized animals. The effects of epiphyseal peptides on the secretory activity of antibody-forming cells depended on the functional state of Peyer's patches. Application of epiphyseal peptides led to a 35% increase (p < 0.05) in the release of immunoglobulins from Peyer's patches in non-immunized rats and a 25% decrease (p < 0.05) in the release of antibody into the incubation medium from the lymphoid organs of immunized animals. These data lead to the suggestion that the activatory effect of epiphyseal peptides on antibody-forming cells in Peyer's patches from non-immunized animals is associated with alpha-adrenoceptors, while their inhibitory action on immunoglobulin release by the small intestine lymphoid organs from immunized animals is not mediated via adrenoceptors.

Adrenergic Agonists↗
PubMed2003

Effect of physical training on blood level of endogenous modulators of beta-adreno- and m-cholinoreactivity in patients with a history of myocardial infarction.

The relative content of myocyte-active factors and endogenous muscarinic receptor blocker in the blood increased, while the concentration of endogenous beta-adrenoceptor sensitizer decreased in coronary patients with a history of acute myocardial infarction. Physical training produced a therapeutic effect, normalized the content of these factors and, probably, improved beta-adrenergic and muscarinic cholinergic regulation of the heart and vessels.

Animals↗
PubMed2003

[Effect of central axotomy of sensory neurones on the mechanoreception recovery in initial regeneration of the injured sciatic nerve in rats].

No apparent effect of lumbar dorsal rhizotomy performed simultaneously with the peripheral nerve injury, has been revealed on the triggering of regeneration of sensitive nerve fibers. Re-innervation of the foot skin by either decentralized regeneration of nerve fibers or those sustaining their connections with the central nervous system (CNS), has been shown to start 30 days after surgery. Using the recording of impulse activity of a single nerve fibre, the mechanical thresholds of decentralized regenerating receptors were found to be significantly higher as compared to the thresholds of the regenerating receptors sustaining their connections with the CNS. The findings suggest that afferent nerve fibers and mechanical receptors formed on the periphery, continue functioning after decentralization and sustain their regenerative capacity after injury. However, in marked contrast, the decrease in sensitivity of regenerating receptors is more pronounced.

Animals↗
PubMed2003

[Projections of the gastrointestinal tract organs on afferent ganglions of the vagus nerve in rats].

Experiments were carried in 42 mature white male rats. We investigated into the projections of different organs of gastrointestinal tract on afferent neurones of ganglia of the vagus nerve in white rats. Horseradish peroxidase-conjugated lectins were used as a tracer. We investigated into metric parameters (diameter of an equivalent circle) and shape parameters (circular factor of the shape) of marked neurocytes using a method of computer video-analysis. To evaluate reliability of the received data, methods of non-parametric statistics were used. It was determined that the largest neurocytes in afferent ganglions are involved in innervation of the root of the long and ileocecal angle, the smallest ones--in innervation of a cervical department of esophagus and liver. The viscero- and somatosensory neurocytes in caudal ganglion of vagus nerve involved in innervation of different organs in white rat, are characterized by selectivity of the shape and by metric parameters.

Afferent Pathways↗
PubMed2003

[Effect of pineal peptides on the adrenal gland cortex glucocorticoid function and behavior in rats orally immunized with ovalbumin].

The influence of intraperitoneal injections of pineal peptides (5 mg/100 g of body mass during first five days of three weeks' oral immunization by ovalbumin) on the rats' behavior in the "open field" tests and on the blood corticosterone level, was investigated. It was found out that rats' oral immunization resulted in increasing of secretion activity of Peyer's patches antibody-producing cells, in decreasing of blood leukocyte cytokine-producing activity, in depression of the searching behavior and locomotor activity and in a significant (p < 0.05) lowering of the blood corticosterone level after 15 minutes in the "open field" tests. The pineal peptide injections caused an intensification of humoral immune response, a more obvious suppression of locomotor activity and searching behavior, and a significant decrease of the corticosterone level compared to the animals intraperitoneally injected by physiological solution. These data indicate that immuno-stimulative effect of pineal peptides combines with their ability to decrease glucocorticoid hormone secretion during stress-reaction.

Adjuvants, Immunologic↗
PubMed2003

[Populations of afferent neurons in the sensory ganglia detected using lectin from Laburnum anagyroides].

The purpose of the present research was the study of afferent neuron subpopulations in vagal caudal ganglia and trigeminal ganglion of adult albino rats using a conjugate of fucose-specific Laburnum anagyroides lectin (LAL) with peroxidase. Histochemical preparations obtained were examined using computer videoanalyzer with the determination of dimensions of afferent neurons and integral optical density (IOD) of their cytoplasm. In the ganglia studied LAL was found to bind to the majority (more than 98%) of neurons. Reaction product was demonstrated in the perikaryon either as discrete granules (Nissl body-type), or as a uniform precipitate. Nucleoplasm in most of neurons remained lightly stained. Determination of IOD of neuronal cytoplasm in various ganglia demonstrated significant differences in degree of LAL accumulation. Analysis of interrelation between neuronal size and IOD permitted to establish non-linear correlation of metric and optical parameters and to detect subpopulations of cells in the sensory ganglia, which were stained with LAL most intensely. Functional specialization of these cells remains to be determined. Thus, a combined application of lectin-histochemical method with a computer videoanalysis of morphological slides enabled the identification neuronal populations and subpopulations in rat afferent ganglia, which are not demonstrated with the standard histological methods.

Animals↗