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Biomedical subjects

V Ia Klimovitskiĭ

Publications and source records attributed to V Ia Klimovitskiĭ.

9 recordsLinked to original sources
PubMed2003

[Problems of exobiology: the origin of life on Earth].

The basic problem of exobiology is origin and evolution of life as a space phenomenon. Consideration is given to the facts for the space origin, spreading in the interstellar space of and invasion of the surface of planets by organic compounds, constituents of archetypes of living systems. The authors bring up to discussion the issues of life development under the conditions of Earth, and formation of the main properties of the living organisms differing in the level of organization. Outlined are some international projects on exobiological research in experiments with bio-objects on space platforms.

Biological Evolution↗
PubMedDate not supplied

[The permeability of rat erythrocyte membranes for sodium and potassium ions during exposure to pulsed electromagnetic field under head-down-tilt hypokinesia].

The effect of a low-frequency (1 and 10 Hz) pulse electromagnetic field (PEMF) on permeability of erythrocyte membrane in 47 rats while being exposed to a 14-day head-down tilt (HDT) and in 60 control rats was studied. After exposure to PEMF (20 min, 6-24 mT) the rats were Na(+)-, K(+)-cotransport and Na+,Na(+)-metabolism, Na and K losses as well as specific activity of Na(+)-, K(+)-ATP in the erythrocytes have been measured. An ability of PEMF to inhibit an ATP activity by 20-30% and to increase the rate of ions loss from the cells has been revealed. Under HDT, these effects are preserved. The possible mechanisms of PEMF effect on an ionic permeability of the membranes are discussed.

Animals↗
PubMedDate not supplied

[Effect of low-frequency electromagnetic fields on the individual functional systems of the body].

This paper is a review of recent publications about the effects of low frequency electromagnetic fields (EMF) (constant and pulsed) on the cardiovascular, neuroendocrine, and blood systems of experimental animals and industrial workers exposed to them. It is reported that the regulatory systems (nervous and endocrine) are highly sensitive to EMF. It is obvious that investigations of hormone-receptor interactions can help better understand EMF effects on the endocrine system and the body as a whole. Published data about EMF effects on the cardiovascular system and blood are often contradictory, probably, because of different estimates of allowable limits recognized in various countries. It is hypothesized that circulatory changes are largely dependent on the central regulatory structures, particularly hypothalamus. White blood responses to the exposure, being most significant among hematological reactions, are also induced, to a certain extent, by regulatory mechanisms. The EMF effects may depend on the initial state and individual properties of the biological organism. It is postulated that the EMF effects on regulatory mechanisms may be related to primary disorders in cellular and mitochondrial membranes.

Animals↗
PubMedDate not supplied

[Disruption of the circadian rhythm of the body temperature in monkeys during head-down tilt hypokinesia].

A rhesus monkey was restrained in the prone position with the head kept at -6 degrees. The day: night cycle was 16:8 and ambient temperature 20-22 degrees C. Skin temperature (ST) in the ankle area and body temperature (BT) in the armpit were measured by thermistors every 16 min during 14 days. Mean daily values of both temperatures decreased continuously beginning with day 5 and reached a minimum on day 11. Between days 5 and 11 the BT rhythm was split into two components, i. e. morning and evening (with the 12-hour periodicity being predominant in the spectrum). The amplitude of the ST rhythm declined and reached a minimum on day 4. On that day the rhythm phase was sharply shifted (6-7 hour delay) and thereafter the amplitude and phase of the ST rhythm gradually restored. The above effects (dissociation of the BT rhythm, drop of the amplitude and delay of the phase of the BT rhythm) can be explained by a transient attenuation of the relationship (release) of circadian oscillators due to a greater load on the mechanisms of adaptation to simulated microgravity.

Animals↗
PubMedDate not supplied

[Model of physiological thermoregulation].

Temperature dependence of energy transformations in the cell being considered as the basis of thermoregulatory reactions in any organism, the mathematical model of energy obtaining and utilization of some formal system which can be considered as a cell prototype is composed. The mode is realized in the form of differential equations which describe the energy balance in the dynamic system and the energy exchange between the system and the environment. The steady state of the system structural elements is interpreted as a "hypothetic" aim of the regulation. Temperature "set interval" and "non-thermal" factors role in the formation of the last is based on the equations solutions which correspond to quasi-stationary states of the system. The model can be used as an element of mathematical description of organism thermoregulation. A scheme of possible synthesis of organism of thermoregulation model is considered.

Adenosine Triphosphate↗
PubMedDate not supplied

[Effects of an impulse electromagnetic field on calcium ion accumulation in the sarcoplasmic reticulum of the rat myocardium].

By means of an ion-selective electrode, the effect of an impulse electromagnetic field with a 1 ms impulse, 10 Hz frequency, and 1-10 mT magnetic induction on calcium transport was investigated in the presence of potassium oxalate by rat heart homogenates. Prolonged exposure (100 min) to the field produced 70% inhibition of Ca2+ transfer across the sarcoplasmic reticulum. This effect is associated with direct inhibition of Ca(2+)-ATPase.

Animals↗
PubMedDate not supplied

[The role of gravitational force in the evolution of living systems (the biomechanical and energy aspects)].

Possible pathways of the origin and development of adaptive mechanisms in the living systems of various levels of organization are considered from the positions of biomechanics and bioenergetics. Main attention is paid to the specific feature of functional rearrangements in the living organisms during change of habitat, at the stage of their exit from water to land. The following problems of interaction between the living systems and gravity during evolution are discussed: cellular level of organization and transition to multicellularity, formation and improvement of the skeletal and skeletal-motor systems in plants and animals, and thermal homeostasis of the living organisms in the gravity field. We showed a leading role of gravity in organization of the morphofunctional status of the living organisms during their evolution.

Adaptation, Physiological↗