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Biomedical subjects

V S Shashkov

Publications and source records attributed to V S Shashkov.

At least 19 recordsLinked to original sources
PubMed2002

[The effect of gravity on the linear velocity of blood flow along the arterial bed in healthy humans].

The ultrasonic Doppler technique was used to determine the effect of gravity on the linear velocity of blood flow in the main arterial vessels in the neck, brain and legs in 67 essentially normal human subjects of both sexes. The hemodynamic effect of gravity was neutralized by placing the subjects in the horizontal position; effects of the force of gravity were stimulated by active upright posture. It was shown that most commonly the arterial blood flow reacts to the orthostatic orientation by reducing the linear velocity, especially in the leg. These results indirectly witness that the hydrostatic pressure gradient on different levels of the arterial system in upright standing humans is not the only factor in reduction of the arterial blood linear velocity.

Adolescent↗
PubMed2000

[Pharmacological prophylaxis of vestibulo-autonomous syndrome (motion sickness) in model investigations].

The authors summarize results of multiyear investigations at the Institute of Biomedical Problems of induced motion sickness and development of prophylactic medicaments representing various classes of biologically active substances (choline blocking agents, sympathomimetics, antihistamines etc.) prescribed singularly or in an combination based on the knowledge of MS-provoking inter-receptor interactions and therapeutic effects of drugs.

Adult↗
PubMed1998

[Problem of orthostatic intolerance in astronauts and perspectives for its pharmacological prevention].

Double-blind placebo-controlled method was applied to study venoconstrictor agent Dihydroergotamine effects on orthostatic tolerance in 8 healthy male-volunteers after 6-hour exposure to antiorthostatic stress (-6 degrees). The drug was able to induce blood centralization and diuresis additional to those caused by the simulated microgravity per se and failed to prevent the orthostatic intolerance. In 6 subjects the studies were repeated with the occlusive cuffs used in order to prevent venous blood return from the vascular bed of the lower limbs during 0-gravity simulation. The occlusive cuffs were shown to eliminate the additional drug-induced blood centralization and diuresis. Orthostatic tolerance in this case occurred to be less affected than in the case of no countermeasure used or in the case when dihydroergotamine was used alone. Thus, it was shown that mechanical prevention of the drug-induced blood centralization from being realized in 0-gravity simulation must be considered as the requirement necessary to permit the drug to perform its beneficial effect on the orthostatic tolerance after the real or simulated weightlessness.

Adult↗
PubMed1997

[Movement disorders in the context of P.K. Anokhin's theory of functional systems].

The authors' own findings and the data available in the literature as to movement diseases (MD) in animals and man were reviewed in the context of P. K. Anokhin's theory of functional systems. The functional system of the human body's gravity center is detailed. There is evidence for that disintegration processes underlying MD first occur in the mnestic sphere since due to genetic and/or ontogenetic causes, memory has no preserved no motor programme required to achieve the end net efficiency of performance of this functional system,--to maintain the definite position of the gravity center of the body and its related vegetative status upon stress-induced vestibular exposures. Based on the above concepts of the pathogenesis of MD, its preventive measures have been proposed and tested, which include drug (nootropic agents) and non-drug (a special complex of physical exercises for children aged 2 to 7 years, which will form permanent motor programs in memory in definite periods of their ontogenesis) measures.

Animals↗
PubMed1990

[Effects of oxiracetam and piracetam on the electrical activity of neurons of the cerebral cortex].

The effect of oxiracetam and piracetam on the spontaneous impulse neuronal activity of the somatosensory cortex of the cat and rabbit was studied. Oxiracetam and piracetam when applied microiontophoretically changed neuronal activity by depressing in the majority of the cases studied or sometimes facilitating the spontaneous firing rate. A small percentage of neurons (about 30%) remains unaffected by the application of the nootropics. In some cases oxiracetam and piracetam diminished the depress effect of morphine and DADLE on the spontaneous impulse neuronal activity.

Animals↗
PubMed1988

[Vestibulo-protective properties of regulatory peptides].

Endogenous opioid peptides take an active part in the pathogenesis of motion sickness (MS). Some regulatory peptides (substances P, gamma and des-tyr-gamma-endorphins) manifest antiemetic properties, unlike opioid peptides and morphine. Thus, we have examined the vestibulo-protective properties of some regulatory peptides during simulation of MS in cats. Vestibulo-protective properties have been discovered in some peptides: sweet water hydra undecapeptide, substances P, gamma and des-tyr-gamma-endorphins. It has been suggested that regulatory peptides take an active part in the genesis of vestibulo-protective disorders during motion sickness.

Animals↗
PubMed1988

Hormonal status and fluid electrolyte metabolism in motion sickness.

In the first experimental series, 10 healthy male test subjects with a high susceptibility to motion sickness showed a significant increase of ACTH, cortisol, STH, prolactin, ADH, aldosterone concentrations, and plasma renin activity after vestibular tests. The 10 subjects with a moderate susceptibility exhibited a still higher increase of the hormones, except plasma renin. The 8 test subjects with a low susceptibility displayed a considerable increase in ACTH, cortisol, and STH after vestibular stimulation. In the second experimental series, the increase of STH, cortisol, ADH, aldosterone and renin occurred immediately after rotation in the moderate susceptibility subjects and an hour after exposure in the high susceptibility subjects. This may be indicative of specific immediate adaptation mechanisms or excitation transfer in the CNS in high susceptibility persons. In the third experimental animal series, the permeability of the blood-brain barrier for 125I and IgG increased after rotation. Greater concentrations of potassium, chloride, and urea in CSF are suggestive of an inhibition process activation in the CNS and, probably, of an active urea transport by the vascular plexus epithelium which maintains constant osmotic pressure of cerebral extracellular fluid and prevents hyper-hydration of CNS neurons.

Adult↗
PubMed1987

[Emetic and antiemetic properties of regulatory peptides].

Emetic and antiemetic properties of opioid peptides, substance "P", beta-lipotropin, and ACTH1-39 have been investigated in experiments on cats. It was shown that morphine, enkephalin, beta-endorphin and DADLE caused vomiting in animals, which was blocked by naloxone. Substance "P", gamma- and des-tyr-gamma-endorphin manifested antiemetic properties similar to those of naloxone. Selective antagonists of delta-opioid receptors ICI 154, 129 blocked emetic action of delta-agonist DADLE but did not prevent vomiting caused by mu-agonist morphine. It is suggested that the vomiting mechanisms of endogenous opioid peptides involve stimulation of mu- and delta-opioid receptors in the chemoreceptor trigger zone of the vomiting centre.

Adrenocorticotropic Hormone↗
PubMed1987

[Functioning of the pituitary-adrenal system during the vestibulo-vegetative syndrome and administration of dalargin and nalorphine].

Changes in ACTH, cortisol, beta-endorphin have been investigated during vestibulo-vegetative syndrome (VVS) and injections of dalargin (leu-enkephalin analog) and nalorphine (agonist-antagonist of opioid receptors) in 9 volunteers with low level vestibulo-vegetative stability. Cumulative coriolis acceleration test during rotations on a special chair was used for VVS modelling. Dalargin (1-4 mg), nalorphine (5 mg) and placebo (NaCl solution) were injected intravenously 5-15 min before rotation. A significant increase in ACTH, cortisol and beta-endorphin plasma levels has been observed. Mean positive linear correlation (r greater than +0.6) between ACTH and beta-endorphin and ACTH and cortisol was noted immediately after the test only when dalargin was injected. It is suggested that in VVS there develops a hormonal conflict, i. e. an adequate hormonal release is disturbed.

Autonomic Nervous System Diseases↗
PubMed1977

[Effect of isoptin on the central and peripheral hemodynamics in hypokinesia in healthy persons].

Central and peripheral hemodynamics was studied by the radioisotope method employing 131I-labelled albumin, the blood flow in the muscles was investigated (using 133Xe) and the longitudinal rheovasogram of the leg and forearm recorded in 10 healthy male volunteers before, during, and after 45-day antiorthostatic hypokinesia. Five of the examines received isoptin, while the remaining 5 formed the control group. Due to the effect of hypokinesia a tendency towards a a decrease in the circulation volume, a reduced stroke index, an increase in the central venous pressure and peripheral resistance, and a decrease in the muscular blood flow were observed. With the prescription of isoptin the changes in the cardiac index and peripheral resistance were corrected, but there was no esstential effect on the level of the venous pressure and the muscular blood flow.

Adult↗