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Biomedical subjects

B I Davydov

Publications and source records attributed to B I Davydov.

At least 19 recordsLinked to original sources
PubMed1989

[The effects of space flight factors on the central nervous system. Structural-functional aspects of radio-modifying action].

The monograph has been dedicated to the analysis of structural and functional changes in the central nervous system of the experimental animals exposed to the isolated and combined effects of space flight factors. There have been shown many changes, which took place in the various anatomic-physiological formations of the brain, and evaluated their significance in organism's responses to the effects of ionizing and nonionizing radiation, hyperoxia, hypoxia, accelerations, vibrations and combined effects of some of those factors. The synergistic, antagonistic and cumulative (simple addition) effects of the investigated stressors along with the radiation factor on the CNS have been stated. This review is prescribed for the specialists in space biology, for physiologists, pathophysiologists, biochemists, radiobiologists and physicians.

Acceleration↗
PubMed1988

[Ultrastructure of the cerebral cortex in the rat after the effect of electromagnetic impulse].

In mature rats an area on the head has been subjected to a single radiation for 1.5 sec with microwaves in the continuous regimen of generation, frequency 2.4 GHz level of the specific absorbed power 5 W/g, that is accompanied with appearance of convulsions. Under anesthesia specimens of the superficial layer of the cerebral superlateral part are taken and subjected to electron microscopical investigation. Immediately after radiation and in 2 h certain disorders in microcirculation and reactive changes of mitochondria in perikaryons, axons, dendrites, synapses of the neurons and in gliocytes are revealed. The mitochondrial changes are designated as "edematous". In 2 and 6 h in karyoplasm of some neurons membranous structures appear; they are interpreted as a result of heat denaturation of the nuclear proteins. In synapses, together with lesions of mitochondria, synaptic complexes undergo destruction and osmiophilic substance is accumulated in the subsynaptic zone along the whole length of the contact. In one day, essential destructive changes are revealed as severe lesions of some neurons, vacuolization and destruction of mitochondria, localized in all the structures. Pathogenesis of the neurological disturbances is based on disturbances of interneuronal interactions, connected with an immediate heat effect of the electromagnetic radiation on the structures responsible for the synaptic transmission and with a rapidly developing tissue hypoxia as a consequence of microcirculatory disturbance and a sharp inhibition of energetic metabolism.

Animals↗
PubMed1979

[Effects of injurying and restoring the body of mice with microwave (2400 MHz) irradiation].

In the experiments on 2200 mice the thresholds of powder density (PD) and time of irradiation were defined, when the death level did not exceed 0.1%. Dependence between the speed ratio of the destruction/regeneration and PD approached the exponential function. The functional dependences obtained quantitatively characterize the adaptive abilities of the mouse organism exposed to microwave irradiation.

Animals↗
PubMedDate not supplied

[Effect of mexamine on the resistance of dogs to acute hypoxic hypoxia].

As demonstrated in experiments staged on dogs mexamine hydrochloride, used in a dose of 20 mg/kg by the intraperiotoneal route 1.5 hours before the onset of acute hypoxic hypoxia increases the resistance of the organism to oxigen deficiency. Mexamine is capable of significantly intensity hypothermy in dogs during acute hypoxic hypoxia.

5-Methoxytryptamine↗
PubMedDate not supplied

[Video display terminals: their electromagnetic safety].

Widespread application of video terminals (VT) has led to accumulating some unambiguous data on harmful effect of electromagnetic and electrical fields on the health. An analysis indicates that the level of electromagnetic and electrical fields is below permissible limits. IRPA/INIC concludes that the electromagnetic effects on VT users health are unharmful. However, the problem of VT use is an integrated one and involves not only radiation but ergonomic aspects and in this context requires further studies.

Computer Terminals↗
PubMedDate not supplied

[Pharmacologic defense of the brain in radiation injury: some arguments].

Based on an analysis of the latest data on the problem of pharmacologic defense, the pro and contra scientific arguments of using pharmacochemical countermeasures to radiation damages of the brain are discussed in succession. A comparative characteristic of positive and negative effects of countermeasures possessing various neurotropic properties is presented. A general scheme of searching for the means of pharmacologic correction of radiocerebral syndrome involving the following stages: pathophysiologic analysis of cerebral disorders; selection of behaviorally significant (psychophysiologic) criteria; search for pharmacochemical correction means; experimental animals studies with extrapolating their results to a man; radiocerebral syndrome simulation (pharmacologic, physical and chemical); field tests; decision-making (medico-biological and formalized approaches) is presented. "Pyramid of complexity" of radiocerebral effects extrapolation from the animals to a man to suit an hierarchy of the biological structures is presented. The effectiveness of conditionally-quantitative relationships of the drugs of prolonged and short-term effect as applied to various radiation syndromes (erythropoietic, gastrointestinal and cerebral) is discussed.

Aerospace Medicine↗
PubMedDate not supplied

[The effect of adrenaline on the succinate dehydrogenase activity in functionally changed (lymphoid leukosis) lymphocytes in mice].

The activity of succinate dehydrogenase (SDH) in lymphocytes of peripheral blood of AKR mice was measured in response to intraperitoneal injection of epinephrine hydrochloride at a dose of 1 mg/kg. SDH reactions to epinephrine were of two types: increase or decrease of activity. The type of reaction depended on the initial enzyme level. The decrease of epinephrine activation of SDH in lymphocytes was found to be correlated with the age of animals and hematological manifestations of hemoblastosis they developed. The percentage of cells with a high SDH activity in hemoblastotic animals was correlated with the count of prolymphocytes and blast cells in peripheral blood.

Animals↗
PubMedDate not supplied

[The effective dosage as the stimulating exposure in fractionated gamma irradiation].

The study of early neurological disturbances (END) in rats after fractionated gamma irradiation with doses of 37.5-225 Gy at dose rate of 30.11 Gy/min has demonstrated that the initial response of animals to pulse ionizing radiation is a function of the electric charge induced by ionizing radiation. A change in the probability of occurrence of each of the END symptoms, with the increased intervals between exposures, is merely an indirect indication of the eliminating mechanisms and is intricately connected with the irritating charge value. The period of dose half-elimination in 16 min. The threshold effective dose rate leading to END is of the order of 2.12 Gy/min. The proposed empiric relationships permit to correlate the probability of END symptom occurrence with the continuous quantitative parameter of fractionated irradiation, that is, with an effective dose as an analogue of the irritating effect.

Animals↗
PubMedDate not supplied

[Effect of urea and pituitrin on cerebral radiation effects in rats].

The administration of urea and pituitrin produced a directed and rapid change in a hydration profile of brain tissue which permitted to modify the severity of cerebral radiation affection in rats, that is, to increase it with hypohydration and to decrease with hyperhydration of the brain.

Animals↗
PubMedDate not supplied

[Epidemiologic studies of the effect of microwaves (neurophysiologic, hematologic and ophthalmologic aspects)].

This paper presents epidemiological and clinical evaluations of subjects exposed to electromagnetic radiations (EMR) in the microwave range with emphasis on neurophysiological, hematological and ophthalmological changes. Special attention is given to neurological and psychogenic effects of EMR as well as to possible development of radiophobia. Ageing, cataract development and genetic signs are considered as objective measures of EMR effects.

Action Potentials↗