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Biomedical subjects

B I Davydov

Publications and source records attributed to B I Davydov.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

[Hyperbolic function of the neuroelectrical effects in the cerebral form of radiation lesions].

A theoretical synthesis of electrical parameters of interaction between gamma radiation and excited membranes of nervous and muscular tissues suggests a correlation between power (dose-rate, R) and duration of exposure (T), of the liminal stimulation of a neuron by gamma radiation: R = 6 + 8/T. In studying early transient neurologic disorders (ETND) the threshold charges of ionizing radiation have been defined for various probabilities of occurrence of one of the ETND symptoms.

Action Potentials↗
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[A multifactorial study on the relative postradiation changes in various categories of behavioral reactions in rats].

The use of the methods of multifactor, orthogonal and composition planning in studying the behavioural disturbances in rats after gamma irradiation with doses of 0.258 to 1.29 C/kg and the application of the proposed method of discrimination of effects by empirical models permitted to establish the informative and adequate dependences of the probability of these disturbances on dose of nonuniform irradiation and the degree of strengthening of the conditioned reflex. It was shown that the effect of radiation decreased, in a discrete manner, the probability of making the first decision by rats in a behavioural task (here we deal with the "dose-response" function). The average time of making the first decision after irradiation was invariable within the dose range under study. Within the range of the studied factors both the value of the dose of whole-body irradiation and the degree of strengthening of the conditioned reflex significantly affected the probability of fulfilling the task by the animals the significance of the radiation dose being several times higher. The effects of the interaction of the two factors, that is, irradiation and the degree of the radiation affection, were insignificant in changing the behavioural reactions under study.

Animals↗
PubMedDate not supplied

[Morphological analysis of the reaction of the animal brain to short-term hyperoxia].

Reactions of various structures of the central nervous system of animals to short-term hyperoxia were investigated, using morphological methods available. Reactive, destructive and compensatory-adaptive changes in the structures taken under study were identified. These changes were nonspecific and similar in sign in rats and dogs. In most cases they were reversible but their polymorphism was different in phylogenetically dissimilar structures.

Animals↗
PubMedDate not supplied

[Patterns of emotional and motivational interrelationships of irradiated male cats].

After gamma irradiation within a wide range of doses (from 5 to 100 Gy) it was found that behavioural response of an emotional type (an evoked "pleasure" test) was more labile than the reaction based on a pronounced congenital hunter motivation (a "predator-victim" test). Exposure (50 Gy) of abdomen, when CNS was unaffected while a pronounced vegetative syndrome of the primary reaction developed within the first two hours, resulted in a more significant decrease in either behavioural pattern than it was observed after irradiation of the head.

Abdomen↗
PubMedDate not supplied

[Changes in synapses after gamma-irradiation of the rat head].

High reactivity and, at the same time, flexibility of interneuronal contacts were observed after exposure of rat head to 2-100 Gy radiation. At high doses (200-400 Gy) radiation-induced changes played a major role in the development of the cerebral form of radiation sickness. A complete asynapsis is probably one of the causes of the animals death "under the ray" (irradiation of the head with a dose of 1000 Gy).

Animals↗
PubMedDate not supplied

[Quantitative analysis of neurological effects after cranio-caudal gamma-irradiation of rats].

A study was made of the frequency and duration of neurological disorders after cranio-caudal irradiation of rats with doses of 7.5-500 Gy delivered to the head. As the mean effective dose increased the neurological disorders occurred in the following order: tremor, rotatory movements hyperkinesia, opisthotonos, and convulsions. The neurophysiological disorders observed were subjected to a pathophysiological analysis.

Animals↗
PubMedDate not supplied

[Electromagnetic radiation in the radiofrequency range: radiation safety].

Existing safety standards for electromagnetic radiation in the radio frequency range, including microwave radiation, adopted in the USSR, Great Britain, Poland, Czechoslovakia, USA, Canada, FRG and recommended by IRPA/INIRC are described. It is proposed to use the value 0.4 W/kg as the basic value of an absorbed dose rate which corresponds to the energy flux density 100 W/m2 for frequencies over 2 GHz. The concepts of an effective dose rate and effective dose are discussed. Various questions of how to provide safety of those working with electromagnetic radiations are considered.

Canada↗
PubMedDate not supplied

[Electromagnetic radiofrequency radiation (microwaves): principles and criteria of standardization, threshold dose levels].

This paper discusses the principles and criteria of standardization of electromagnetic radiation in the radiofrequency range. The concept of risk as a standardization criterion normally used in the radiobiology of ionizing radiation can also be employed in the standardization of electromagnetic radiation. It is recommended to use as major parameters of "harmfulness" longevity, cataract formation and genetic effects in vivo as well as mortality rate in the laboratory experiment. The value of 0.1% is taken for the primary risk level. The paper describes approaches to the extrapolation of experimental data concerning threshold effects. As follows from pertinent calculations, the specific absorption of the electromagnetic dose rate for the personnel is 0.4 W/kg during one hour exposure.

Animals↗
PubMedDate not supplied

[Behavior of cats following gamma-irradiation of the head: the induced pleasure test].

A decrease in the degree of manifestation of the induced pleasure response of male cats to the administration of valerian tincture was observed during the first 1-2 h following gamma-irradiation of the head with a dose of 1.29 C/kg. It is suggested that the absence of the reaction during the first 10-15 min after exposure is indicative of the presence of the phase of a pronounced excitation in the C.N.S. of the exposed animals.

Animals↗