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Biomedical subjects

V N Kazakov

Publications and source records attributed to V N Kazakov.

At least 19 recordsLinked to original sources
PubMed2003

[Projections of the dorsal raphe nucleus and midbrain central gray substance to the cat limbic system].

Morphological organization of connections of ventro-lateral (nociceptive) and dorso-lateral (analgetic) midbrain central gray (vl SGC and dl SGC), as well as of dorsal raphe nucleus (analgetic zone, Rd), with different limbic structures, responsible for the formation of various emotional states, was studied in 26 cats. The methods of electrical destruction of brain areas were used that were followed by the light and electron microscopic study of degenerating fibers and synapses. Heterogeneity of connections of above mentioned formations with different limbic structures was demonstrated. Connections Rd and dl SGC with upstream limbic structures were found to be very similar in their organization and expression. Connections of vl SGC with the same structures were significantly different. It is suggested that similar (antinociceptive) function of dl SGC and Rd has determined the likeness of their connections. This, in combination with the heterogeneity of SGC in conduction of the pain and analgesia, supports the identification of two brain systems: nociceptive, conducting pain sensitivity, and antinociceptive, inhibiting its conduction. The nociceptive system includes the following structures: vl SGC, posterior and lateral hypothalamic nuclei, preoptic area. In the antinociceptive system two subsystems could be distinguished: midbrain units of these subsystems are localized in different structures (Rd and dl SGC), while the upstream ones are found in the same hypothalamic nuclei--ventromedial, dorsomedial, paraventricular. As far as septum, amigdala, hippocampus and cingular cortex are concerned, it was found impossible to refer them to any of these systems--either nociceptive or antinociceptive--basing solely on the findings of morphological studies because of approximately similar representation of axons of neurons in vl SGC, dl SGC, Rd in these structures.

Afferent Pathways↗
PubMed2003

[Effect of modulator of the signal transmission from opioid receptor to sodium channels on hypothalamus self-stimulation].

We investigated effects of different doses of a new preparation comenic acid as a modulator of the transmission of signals from an opioid receptor to slow sodium channels on the hypothalamic rewarding system in male Wistar rats. Comenic acid has been shown to inhibit the reaction of the hypothalamic self-stimulation (SS) in a dose-dependent fashion with the strongest effect at doses of 28.8-30 mg/kg. We observed a decrease in the rate of lever-pressings, induced by the threshold for SS current intensity, and an increase in the threshold for the response of SS, or its cessation. The similar suppressing effect of the preparation was found at its repeated injections. Thus, those results showed that comenic acid failed in both activation of the rewarding system of the lateral hypothalamus and adaptation to it.

Animals↗
PubMed2003

[Physical and chemical properties of the condensate of breathed-out air in healthy people].

The physical-and-chemical condition of condensate of breathed-out moisture (CBM) was studied by the computer-aided analysis of axis-symmetric drops' form in healthy subjects; such condition was found to depend on sex, age and smoking-addiction of the examined persons. The surface tension of the mentioned moisture correlated with its viscoelastic index and with relaxation. The metabolites of nitric oxide, lipids, urea, lactic acid (not uric acid) and of hydrogen peroxide were found to influence the physical-and-chemical parameters of respiratory moisture. Hydrogen peroxide had a reverse correlation with the CBM viscoelastic module. A status of the pulmonary surfactant can be evaluated by using the studied physical-and-chemical CBM parameters.

Adult↗
PubMed2000

Studies on the application of dynamic surface tensiometry of serum and cerebrospinal liquid for diagnostics and monitoring of treatment in patients who have rheumatic, neurological or oncological diseases.

Human biological liquids comprise various surfactants, which adsorb at liquid interfaces and lead to a variation in surface tension. The adsorption processes involving low molecular weight surfactants, proteins and phospholipids play a vital role in the physiological functions of the human organism, especially if large surfaces are involved (e.g., gas exchange in lungs, metabolism of kidneys, liver and brain). Dynamic surface tensiometric studies of biological liquids like serum and cerebrospinal fluid provide surrogate parameters that reflect surface tension phenomena. We provide dynamic surface tension data of serum and cerebrospinal fluid that were collected from healthy volunteers and patients with rheumatic, neurological or oncological diseases. Our studies indicate that dynamic surface tension data are helpful for diagnostic purposes and for monitoring of therapeutic interventions.

Adsorption↗
PubMed2000

Dynamics of protein and mixed protein/surfactant adsorption layers at the water/fluid interface.

The adsorption behaviour of proteins and systems mixed with surfactants of different nature is described. In the absence of surfactants the proteins mainly adsorb in a diffusion controlled manner. Due to lack of quantitative models the experimental results are discussed partly qualitatively. There are different types of interaction between proteins and surfactant molecules. These interactions lead to protein/surfactant complexes the surface activity and conformation of which are different from those of the pure protein. Complexes formed with ionic surfactants via electrostatic interaction have usually a higher surface activity, which becomes evident from the more than additive surface pressure increase. The presence of only small amounts of ionic surfactants can significantly modify the structure of adsorbed proteins. With increasing amounts of ionic surfactants, however, an opposite effect is reached as due to hydrophobic interaction and the complexes become less surface active and can be displaced from the interface due to competitive adsorption. In the presence of non-ionic surfactants the adsorption layer is mainly formed by competitive adsorption between the compounds and the only interaction is of hydrophobic nature. Such complexes are typically less surface active than the pure protein. From a certain surfactant concentration of the interface is covered almost exclusively by the non-ionic surfactant. Mixed layers of proteins and lipids formed by penetration at the water/air or by competitive adsorption at the water/chloroform interface are formed such that at a certain pressure the components start to separate. Using Brewster angle microscopy in penetration experiments of proteins into lipid monolayers this interfacial separation can be visualised. A brief comparison of the protein adsorption at the water/air and water/n-tetradecane shows that the adsorbed amount at the water/oil interface is much stronger and the change in interfacial tension much larger than at the water/air interface. Also some experimental data on the dilational elasticity of proteins at both interfaces measured by a transient relaxation technique are discussed on the basis of the derived thermodynamic model. As a fast developing field of application the use of surface tensiometry and rheometry of mixed protein/surfactant mixed layers is demonstrated as a new tool in the diagnostics of various diseases and for monitoring the progress of therapies.

Adsorption↗
PubMed2000

Integration of thermal and osmotic afferent signals in the preoptic/anterior hypothalamic neurons.

Our in vivo experiments were aimed at studying afferent links of the preoptic/anterior hypothalamus system, which integrates thermal and osmotic homeostasis. Special attention was paid to using stimulation intensities within the normal physiological range. The experiments were carried out on adult cats anesthetized with ketamine (25mg/kg) and inhalation of nitrous oxide (75 vol.%). Short-term shifts in the osmotic pressure within the cerebral vasculature were induced by infusions of 200-500 microl 3.0% or 0.2% NaCl solutions into the homolateral a. carotis (hyper- and hypoosmotic stimulations, respectively). Thermal stimulation was provided by local heating or cooling of the contralateral forelimb pad skin (+/-7.0 degrees C range). Reactions of preoptic/anterior hypothalamus neurons were classified into four types: monophasic activation, monophasic inhibition, and biphasic responses including excitation followed by inhibition or primary inhibition followed by activation. Monophasic activation was a very common occurrence among preoptic/anterior hypothalamus neuronal reactions. The responsiveness of thermosensitive preoptic/anterior hypothalamus neurons to hyperosmotic stimulation turned to be noticeably higher than that to hypoosmotic stimulation. Practically equal proportions of warm- and cold-sensitive neurons demonstrated changes in the firing activity resulting from intracarotid infusions of 3.0% NaCl solution. Infusions of 0.2% NaCl solution induced firing rate modifications in 26% (12/46) of warm-sensitive and in 32% (18/39) of cold-sensitive neurons. Cold-sensitive neurons displayed a higher sensitivity to a short-term osmotic pressure elevation in the cerebral vasculature (63%, 33/52) than warm-sensitive neurons did (43%, 22/52, P<0.05). In our study, a maximum similarity in the response types was observed when hyperosmotic infusion and skin cooling were applied, while a maximum disagreement was found when hyperosmotic stimulations were combined with skin heating. There is no doubt that preoptic/anterior hypothalamus neurons play a crucial role in the maintenance of body temperature. Several studies have also shown that osmoregulation can be affected by shifts in peripheral and hypthalmic temperatures. Information on the neurol mechanisms of interactions between the thermo- and osmoregulatory circuits in the hypothalamus remains limited. We discuss the obtained data considering the "set-point theory" of thermal hameostasis maintenance.

Animals↗
PubMed2000

[Dynamic surface tension of blood in chronic dust bronchitis in coal mines workers].

Chronic dust bronchitis in miners is associated with increase in dynamic surface tension of blood at short (t = 0.01 s) and medium (t = 1 s) surface lifetimes with lower declination angle of interphase tensiograms curve. Surface tension disorders were similar to those in experimental dust bronchitis. There are correlations between surface tension parameters and the workers' underground length of service, some mining geologic conditions and serum level of proteous and lipid surfactants.

Adult↗
PubMed2000

[Dynamic interphasic tensimetry of blood and urine in systemic lupus erythemotosus].

AIM: To study dynamic surface tension (DST) of blood and urine in SLE patients. MATERIALS AND METHODS: Clinical, immunological examinations, DST of blood and urine using computer tensiometers were made in 67 SLE patients aged 15 to 62 years. RESULTS: Changes in interphasic tensiograms in males and females were characterized regarding the course, activity of the pathological process and the presence of certain clinical symptoms. Effective therapy return to normal DST of the biological fluids. Correlations between interphasic tensiograms of blood, urine and levels of proteins, lipids, non-protein and inorganic surfactants and surface-inactive substances were established as well as relations of DST with biochemical composition of the biological fluids. CONCLUSION: The above diagnostic method may be useful for differential diagnosis, assessment of the clinical course, activity of the disease, control over effectiveness of the treatment.

Adolescent↗
PubMed1999

[Pulmonary surfactant status in experimental dust-induced bronchitis based on the data from dynamic interphase tensiometry].

The disease was simulated by inhalation of dust containing 29% of free silica in Wistar male rats during 8 months. One group of the subjects was kept under 26-28 degrees C and other one--under 38-40 degrees C. Dynamic surface tension of lung tissue homogenate was studied by means of computer tensiometer MRT (Lauda, Germany). Interphase tensiometry precisely characterizes state of lung surfactant in experimental chronic dust bronchitis. Equilibrium surface tension and surface tension for 0.01 and 1 sec deteriorate during combined exposure to silica dust and heating microclimate. The studies demonstrated strong correlation between interphase tensiogram parameters and individual lipids content of lung surfactant. Surface tension is related to the state of lipids peroxidation in lungs and antioxidant systems.

Animals↗
PubMed1998

[Dynamic surface tension of blood and synovial fluid in rheumatoid arthritis].

AIM: Assessment of the dynamic surface tension (DST) of blood serum (BS), synovial fluid (SF) in various courses of rheumatoid arthritis (RA). MATERIALS AND METHODS: Forty three patients with RA and 63 apparently healthy individuals were examined. DST of BS and SF was determined in the computer-aided tensiometer and some blood biochemical parameters were also measured. RESULTS: DST of BS in patients with RA were found to be higher than the normal values and some parameters c beta 2 and beta 3) of BS DST did not significantly differ from the normal values whereas others (beta 1 and gamma proved to be much lower. Depending on the disease course variants, there were some differences in these DST changes. There was a feedback between DST parameters and the levels of immunoglobulins, beta 2-microglobulin, and lipids in blood. CONCLUSION: Assessment of BS and SF DST may be useful in the differential diagnosis of RA, in the determination of its intensity and prognosis, and therapeutical efficiency.

Adolescent↗
PubMed1998

[Dynamic middle-phase tensiometry of blood and urine in female patients with malignant tumors of the reproductive organs].

An improved version of the MPT2 (LAUDA) computerized tensiometer (Germany) was used to measure dynamic surface tension (ST) of blood and urine by the maximum bubble pressure method in patients with tumors of the uterus, vagina and cervical canal. Relatively low blood and urine ST values at t-->infinity and serum at t = 1 s were registered. Combined radiotherapy involved oppositely-directed changes in the equilibrium (static) ST of the biological fluids as well as a urine ST inhibition in the surface short-life range (t = 0.01 s). The slope of blood serumtension curves by the end of treatment was close to that in healthy females.

Blood↗
PubMed1996

[DNA synthesis in heterodikaryons obtained by the fusion of long-term stimulated cells of the NIH 3T3 line with short-term stimulated cells].

Serum-deprived (0.2%) resting NIH 3T3 mouse fibroblasts, stimulated for 0.5-4.0 h by serum (10%) or PDGF (beta-beta homodimer) (early cells), were fused with stimulated cells taken 10 h after changing the medium to one containing 10% serum DNA synthesis was investigated in the nuclei of monokaryons, homodikaryons and heterodikaryons, using radioautography with the double-labeling technique. Preincubation of resting cells with serum for 3 h or with the competence factor PDGF for 1.0-1.5 h abolished their ability to suppress DNA synthesis in late stimulated nuclei in heterodikaryons. Actomycin D restores the inhibitory capacity of resting cells stimulated by PDGF but not by serum. The results give evidence that the acquirement by resting cells of competence for DNA replication includes as a necessary step the down-regulation of intracellular growth inhibitors, and thus serum can overcome the influence of endogenous growth inhibitors, at any rate, by two ways.

3T3 Cells↗
PubMed1995

Transient inhibition of protein synthesis induces expression of proto-oncogenes and stimulates resting cells to enter the cell cycle.

There is evidence that resting cells are able to produce molecules with antiproliferative activity, some of which behave as short-lived repressor proteins. We suggest that transient inhibition of protein synthesis in resting cells would lead to a decrease in the levels of these negative growth regulators and might, therefore, promote mitogenic responses. We report that treatment of resting (serum-deprived) NIH 3T3 cells with cyclocheximide (CH) or puromycin induces expression of c-fos, c-jun and c-myc proto-oncogenes in a manner similar to that of platelet-derived growth factor (PDGF). Actinomycin D (Act D) abrogates the induction of proto-oncogene expression. Transient inhibition of protein synthesis by CH or puromycin also induces the resting NIH 3T3 and C3H 1OT1/2 cells to enter the cell cycle. Inhibition of new RNA or protein synthesis abolishes the proliferative response. These findings show that control mechanisms at both transcriptional and translational levels are operative in the resting cells treated with protein synthesis inhibitors. Cell fusion experiments with resting and serum-stimulated NIH 3T3 cells revealed that brief pre-incubation of resting cells with either PDGF, CH or puromycin abrogates their ability to suppress the onset of DNA synthesis in the nuclei of stimulated cells in heterodikaryons. However, the abrogative effect of PDGF disappeared in the presence of Act D, whereas the effects of protein synthesis inhibitors did not, indicating their independence of the induction of transcription. The data suggest that the observed effects of protein synthesis inhibitors are connected with elimination of some short-lived negative growth regulators, since a brief translational arrest is sufficient for the resumption of DNA synthesis in the nuclei of stimulated cells blocked by resting cells in heterodikaryons.

3T3 Cells↗
PubMed1993

Sources of cortical, hypothalamic and spinal serotonergic projections: topical organization within the nucleus raphe dorsalis.

Retrograde axonal transport of fluorescent tracers (primuline, FluoroGold and Nuclear Yellow) from the spinal cord, frontal cortex, lateral hypothalamus to various neuronal groups of the midbrain periventricular gray substance (periaqueductal gray matter) and to the dorsolateral pontine tegmentum in the rat has been studied. Two large groups of serotonin-containing neurons have been found to be localized in the dorsomedial region of the nucleus raphe dorsalis. They are sources of projections into the thoracic segments of the spinal cord. A part of these neurons gives divergent axon collaterals to the frontal cortex and to the spinal cord. Non-collateral projections of the dorsolateral pontine tegmental catecholaminergic neurons to the spinal cord and the frontal cortex have been revealed. The data obtained give support to the fact that antinociceptive effect of stimulation of the "pure analgesic zone" [Fardin et al. (1984) Brain Res. 306, 105-123.] of the midbrain periaqueductal gray matter may be due to direct involvement of the nucleus raphe dorsalis into a descending control over transmitting nociceptive stimuli at the spinal cord level. Neurotransmissive and neuroregulatory roles of separate cortical, hypothalamic and spinal serotonergic projections of the nucleus raphe dorsalis neurons are discussed.

Animals↗
PubMed1992

Influences from different areas of the cerebral cortex on preoptic neurons: morphological and electrophysiological data.

Spatial organization of neurons in the prefrontal and cingulate cortex, cortex of the piriform lobe and the hippocampus which project axons to the preoptic region, has been studied in cats using horseradish peroxidase tracing. Cortical areas were selected taking into consideration their phylogenetical distinctions. The prefrontal cortex was found to send a major portion of fibres to the preoptic region, while the density of units forming such connections was maximal in the cingulate cortex. Field potentials and neuronal reactions of the medial and lateral divisions of the preoptic region and the adjacent hypothalamic zones were studied in ketamine-anaesthetized cats. The most pronounced field potentials were recorded in the preoptic region upon stimulation of the cortex of the piriform lobe and cingulate cortex. There was a close correlation between the responses of single neurons and components of the field potentials. The majority of neurons responding to cortical stimuli were located mainly in the lateral preoptic region, where the larger amount of primary excitatory reactions were recorded. The medial preoptic region contained a smaller number of responsive neurons prevailingly generating the primary inhibitory reactions. For the lateral preoptic region the inhibition/excitation ratio was 0.6:1 at all cortical stimulations, but for the medial region it was 5.8:1. In the preoptic division adjoining the bed nucleus of the stria terminalis, the primary inhibitory reactions considerably prevailed over the primary excitatory; on the other hand, in the supraoptic nucleus the primary excitatory reactions prevailed weakly (ratios of 4.9:1 and 0.7:1, respectively). The preoptic region was found to be a zone of wide convergence of cortical inputs to single cells, where three-quarters of neurons responded to the stimulation of two, three or even four cortical areas.

Animals↗
PubMed1992

Protein synthesis inhibitors, like growth factors, may render resting 3T3 cells competent for DNA synthesis: a radioautographic and cell fusion study.

Serum-deprived (0.1-0.2%) resting NIH 3T3 mouse fibroblasts pre-incubated with cycloheximide (7.5 micrograms/ml), or puromycin (10 micrograms/ml), were fused with stimulated cells taken 10 h after changing the medium to one containing 10% serum, and DNA synthesis was investigated in the nuclei of monokaryons, homodikaryons and heterodikaryons using radioautography with the double-labelling technique. Pre-incubation of resting cells with inhibitors of protein synthesis for 1-4 h abolished their ability to suppress DNA synthesis in stimulated nuclei in heterokaryons. Three hours after the removal of cycloheximide from the medium, the resting cells acquired once again the inhibitory capacity for entry of stimulated nuclei into the S period. This inhibitory influence disappeared also in the case of post-fusion cycloheximide application as well as following an 8-12 h pre-treatment of resting cells with actinomycin D (1 microgram/ml) prior to fusion. Pre-incubation of resting cells for 12 h with PDGF (1 u/ml-1) followed by an 8-48 h incubation in serum-free medium stimulated the onset of DNA synthesis. A brief exposure (45 min) of resting cells to cycloheximide (7.5 micrograms/ml), or puromycin (7.5 micrograms/ml), exerted a similar effect, inducing by itself the entry of cells into the S period. The results support the assumption that acquirement, by resting cells, of competence for DNA replication includes as a necessary step the down-regulation of intracellular growth inhibitors whose formation depends on protein synthesis.

3T3 Cells↗