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Biomedical subjects

L D Klimovskaia

Publications and source records attributed to L D Klimovskaia.

At least 19 recordsLinked to original sources
PubMed1976

[Change in the evoked potentials of the brain exposed to a constant magnetic field].

The influence of the constant magnetic field (CMF) upon the cerebral and cerebellar cortex potentials evoked by the sciatic stimulation was studied in rats. During the exposure to the CMF there occurred an increase of the evoked potentials in amplitude and the appearance of additional waves in their structure. The effect was enhanced with increase in the intensity of magnetic field within the range of 500-4000 oe.

Animals↗
PubMedDate not supplied

[Autonomic reactions in rabbits exposed to a constant magnetic field].

Chronic experiments on rabbits have shown that their exposure to a constant magnetic field of 4500 oersted for 3 hours causes a transient hypotension, a decrease in the respiratory rate and a trend for bradycardia. Immediately after the exposure the pressor reaction and bradycardia level decrease and by the end of the first day they increase. At this time the respiratory rate increases in response to the administration of epinephrine, acethylcholine or stimulation of the midbrain reticular formation. The exposure does not decrease the compensatory possibilities of the cardiovascular and respiratory systems. This follows from their reactions to accelerations of 6 and 10 g.

Acceleration↗
PubMedDate not supplied

[The character of changes in the background and superimposed rhythmics of cerebral biopotentials in rabbits exposed to a steady magnetic field of high intensity].

During a total action of a static magnetic field (SMF) of 1000--4000 Oe, high-amplitude synchronized discharges appear in the electrograms of the cortical and subcortical parts of the rabbit brain. An automatic frequency analysis exhibits increased bioelectrical activity in the range of 8 to 30 c/s with no substantial changes in slower rhythms. The effect increases as the field becomes stronger. A SMF of 1000 Oe tends to facilitate the photic driving which persists as an after-effect. In SMF of 3000 Oe the driving reaction is weakened; it is rapidly restored after cessation of the SMF action.

Animals↗
PubMedDate not supplied

[Reactivity of the sympathetic-adrenal system and physical loading tolerance in multiple exposures to a permanent magnetic field].

For 30 days rats were exposed daily 3 hrs a day to a constant magnetic field of 1.6 T. The time within which the rats were swimming with a load until they were fatigued was measured and the concentration of catecholamines in blood and adrenals was determined. Two stages of the response to the magnetic field were identified. During the first stage (1-15 days) physical work capacity increased and the reactivity and reserve ability of the sympatho-adrenal system (SAS) grew. During the second stage (30th day and early recovery period) work capacity returned to normal and the SAS reactivity decreased, although the catecholamines stored in the adrenals remained unchanged. These findings indicate that the SAS is involved in mechanisms underlying changes in work capacity and adaptation processes during exposure to a constant magnetic field.

Adrenal Glands↗
PubMedDate not supplied

[Electrical resistance of the brain tissue of rats exposed to a permanent magnetic field].

The cortical impedance of the large hemispheres of nembutal-anesthetized rats exposed to a constant magnetic field of 0.1, 0.4 and 1.6 T was investigated. During 20 min. exposure the impedance decreased (at the expense of a decrease in both of its components--capacity and active resistance). The impedance decrease was more pronounced (up to 93%) and statistically significant in a field of 1.6 T. After exposure the impedance decrease persisted for 10 min.

Animals↗
PubMedDate not supplied

[Characteristics of the effects of the midbrain reticular formation on the heart and respiration in exposure to centripetal accelerations].

Experiments were carried out on white rats and rabbits exposed to transverse accelerations of 6--10 g for 5 min. Before, during and after centrifugation the reticular formation of the midbrain underwent high-frequency electric stimulation. During centrifugation the inhibitory effects of the reticular formation on the cardiorespiratory rhythm decreased, whereas stimulatory effects either remained unchanged or increased.

Acceleration↗
PubMedDate not supplied

[Bioelectrical activity of the neuromuscular and sympathetic systems exposed to a constant magnetic field].

The experiments on an isolated frog neuromuscular preparation gave evidence that an exposure to stable magnetic fields of 1000-4000 Oe did not influence the time parameters, amplitude and pattern of the action potentials of the gastrocnemius muscle induced by ischiatic nerve stimulation with single impulses. Similar results were obtained from an analysis of electric responses of the upper cervical sympathetic mode to the stimulation of preganglionar fibers in in situ experiments on urethane anesthesized rabbits subjected to a total exposure of a stable magnetic field (500-3000 Oe). In addition, an exposure to a stable magnetic field of 4000 Oe brought about a decrease of the level of depression of the action potential of muscles after conditioning tetanus.

Action Potentials↗
PubMedDate not supplied

[Effect of triftazin and elenium on changes in evoked bioelectric activity of the brain after exposure to magnetic field].

Experiments were carried out on white rats anesthetized with nembutal. Evoked potentials (EP) of the sensorimotor cortex of the large hemispheres, reticular formation of the midbrain and cerebellum resulting from the stimulation of the sciatic nerve were recorded. The exposure to a constant magnetic field of 0.4 T led to an increase of the amplitude and a complication of the shape of EPs due to the appearance of new components. Pretreatment with triphtazine and elenium suppressed the magnetic field effect.

Animals↗