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Biomedical subjects

A V Ovchinnikov

Publications and source records attributed to A V Ovchinnikov.

At least 19 recordsLinked to original sources
PubMed2002

[Brain somatosensory evoked potentials in myofascial pain syndromes].

Brain somatosensory evoked potentials were studied in 113 patients with chronic myofascial pains. Comparing to milder pain, pronounced pain syndrome revealed more significant functional changes (generators for pathologically enhanced excitability), on higher levels of nervous system. At the same time, in milder pain, a large quantity of low activity generators were detected that may indicate subnormal antinociceptive system activity. After treatment, the number of generators of pathologically enhanced excitation decreased significantly with migration to caudal nerve system regions. These changes may be a neurophysiological basis for myofascial pain exacerbations.

Adult↗
PubMed1994

[The management problems in organizing medical care under extreme conditions (based on the experience of medical drills)].

Taking into account the multipolarity of the existing disaster protection system the problem of the effective command is considered to be one of the most important questions in this matter. The article deals with the disaster protection forces handling during exercises under the title: "Action coordination between civilian federal health service facilities and military medical service during emergency health care and specialized treatment".

Disaster Planning↗
PubMed1986

[Intersensory interactions in the CNS of Helix lucorum].

Hair cell responses to adequate stimulation of statocyst, eye and chemoreceptors of the optic tentacle bulb were studied by means of intracellular and extracellular recordings. Hair cells increased firing frequency to titling of the statocyst. Displacement of the statocyst caused a depolarizing wave with superimposed spikes in the hair cell. This depolarizing wave or generator potential increased in proportion to magnitude of displacement. The onset of a light flash and the illumination of eye photoreceptors caused a short-latency (0.3-2 s) increase in the firing frequency of hair cells. The latency of the response was in reversed proportion to the light intensity. Adequate stimulation of chemoreceptors of optic tentacle bulb caused a long-latency (20-40 s) discharge response in the hair cell. In some cases adequate stimulation of photoreceptors and chemoreceptor pathway caused inhibitory responses in 2 of above 50 hair cells.

Animals↗
PubMed1986

[Morphologic features of the chemosensory, visual and vestibular pathways of Helix lucorum].

The structure of chemosensory, visual and statocyst pathways of the snail Helix lucorum has been studied by means of five histological methods. The chemoreceptors of the optic tentacle bulb, small and large neurons of tentacle ganglion and bipolar cells of olfactory nerve send their processes to the CNS of the mollusc. In the CNS these processes divide into many clusters of branches. All protocerebral cells and the cluster of neurons of the commissural part of metacerebrum send their processes within the olfactory nerve towards the periphery. The axons of eye cells terminate in the enlargement of optic nerve near the eye; so do the CNS cells and neurons of the optic nerve. In the neuropile of pleural part of metacerebrum a region of ramification of cell axons of the visual pathway is found. Hair cells of statocyst send their axons within the static nerve to the cerebral ganglion (CG). Small cells of metacerebrum send their axons towards the statocyst. In the neuropile of ipsilateral CG some processes of statocyst pathway cells divide into many thin branches; others--cross to the contralateral cerebral neuropile via the commissure joining two CG. In the neuropile of contralateral ganglion these processes give off a spray of many branches just as in the ipsilateral ganglion. The axons of the visual pathway cells and statocyst pathway cells ramify in the same region.

Animals↗
PubMed1985

[Spontaneous activity of the hair cells of the snail statocyst and changes in it as a result of intracellular stimulation].

The activity of hair cells in the stotocyst of Helix lucorum was studied by means of intracellular recording. Maximal magnitude of input resistance of hair cell membranes was observed in the range of the injected hyperpolarizing current between 0 and 0.1 nA. Voltage noise was a specific type of hair cell activity. It was independent of synaptic activity and had no pacemaker nature. The voltage noise depended only on the contact between hair cell cilia and statoconia. Hair cell depolarization enabled to reveal the pacemaker properties of the receptor membrane. Spike-triggering zone was found to be located in the axon of hair cell. IPSP recorded in the hair cells of the preparations with the static nerve cut confirmed the existence of inhibitory interactions within the statocyst.

Animals↗
PubMed1985

[Hair cell interactions in the statocyst of the snail].

Hair cell interactions within a statocyst of the snail (Helix lucorum) were studied by means of intracellular and extracellular recording. The obtained data demonstrated: some hair cells separated by less than or equal to 90 degrees on the circumference of the statocyst were electrically coupled; the electrical synapses were polarized because coupling coefficients within pairs of cells were not symmetrical (in one direction the coefficient was 10 times greater than in the other); some connections between hair cells located at less than or equal to 90 degrees from each other had electrochemical nature; excitatory chemical component of such interaction had a direction opposite to the effective electrical conduction; there were also inhibitory interactions between hair cells; some of them were monosynaptic chemical inhibitory ones (receptors were located approximately at 180 degrees from each other); others were polysynaptic weak interactions (hair cells were separated by more than 90 degrees-100 degrees on the circumference of the statocyst); all types of the interactions between hair cells were observed in preparations with the static nerve cut.

Animals↗
PubMedDate not supplied

[Visualization of data from statistical analysis of the parameters of somatosensory evoked potential components].

A method is proposed to construct bar charts of statistical differences in the parameters of somatosensory evoked potentials, which simultaneously reflect the level of sensitization and reactivity of pathological excitation generators forming in the central nervous system in chronic pain syndromes. This approach can promote visualization and objectification of functional disorders of the central nervous system during treatment. Moreover, there may be prognosis of a degree of chronization of the pain syndrome.

Chronic Disease↗
PubMedDate not supplied

[Computerized planning of radiotherapy].

The hypophysis was studied by MR tomography in 148 patients with the most prevalent diseases of the hypothalamohypophyseal system and in 13 ones with primary hypothyrosis. The findings evidence a great variety of changes in the MRT picture in the examinees. The method permits a reliable diagnosis of hypophyseal macroadenoma and of an 'empty' sella turcica. Qualitative and quantitative criteria for MRT diagnosis of these conditions are suggested. The diagnostic value of MRT for the detection of macroadenomas is still to be researched. The method was effectively used for a dynamic follow-up of the hypophyseal status in the course of pathogenetic therapy; the formation of an 'empty' sella turcica is possible against the background of dopamine agonist therapy and substitution therapy of primary hypothyrosis.

Adolescent↗