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Biomedical subjects

N D Eksler

Publications and source records attributed to N D Eksler.

10 recordsLinked to original sources

[A system of introduction of the results of scientific research on hygiene into practical health care and national economics].

The country's socio-economic development necessitates further elaboration of new approaches to the introduction of hygienic research results into practice. The main criterion for choosing proper research techniques lies in their economy-type efficiency, both social, medical and economic. A new system of hygienic research introduction should be based on financial and economic stimuli, establishment of a network of inventive firms, as well as supported by an effective mechanisms of information feed-back with due account of health indices.

Delivery of Health Care↗

[Functional origin of the respiratory system in ontogeny. II. The biological importance of the act of birth and the start of extrauterine respiration].

The programme preparation of the fetus for extrauterine autonomic development in the air medium is completed during the process of natural generic act. The postnatal apnea appears to be the result of the fetus central nervous system depressive state. This depression originates in prenatal period and continues during the delivery. The so-called first breath occurs as a results of overcoming of the depressive influences action and the renewal of automatic activity of the respiratory center which has been temporarily switched off.

Adaptation, Physiological↗

[Formation of respiratory system function in ontogeny. I. Intrauterine respiratory movements].

The fetus rhythmic respiratory movements originate long before the birth at a certain stage of its intrauterine development, i. e. the rhythmic respiratory activity is formed before the delivery. As the fetation takes place the character of respiratory system rhythmic activity shifts to stabilization of respiratory muscles rhythmic action towards the termination of gestation. The fetal respiratory movements are inhibited with the beginning of the generic act.

Animals↗

Experimental study of the mechanism and indices of harmful effects of certain chemical substances on the central nervous system.

The task of the second stage of Soviet-American cooperation on the problem of environmental health science was to explain the question of the comparative sensitivity of methods used in both countries, as well as the indices of harmful effects for the same toxic substance (carbon disulfide), with the purpose of determining the most informative methods of assessing the influence of atmospheric pollutants on organisms. The application of neurophysiological research methods (recording total electrical activity of the cortex and cortical structures of the brain, studying amplitude-time characteristics of averaged evoked potentials of the optical cortex, investigating sensory and convulsive thresholds) has made it possible to explain the neurophysiological basis of the effect of carbon disulfide on the central nervous system-the perturbation of cortical inhibition processes and the increase of excitation in amygdalate structures, both of which play an important role in the fixation process of temporary connection. The compilation of data from neurophysiological and neurochemical investigations show that neurophysiological changes are associated primarily with a decrease in enzymic breakdown of free neuraminic acid. The study of the average evoked potentials in humans during exposure to carbon disulfide concentrations of 0.09 mg/m(3) revealed a tendency to decrease the short latent amplitude components and increase the long latent amplitude components of the averaged evoked potentials. The study of operant behavior in rats revealed a characteristic change in the instrumental alimentary reactions under long-term (3 months) exposure of carbon disulfide to a concentration of 16 mg/m(3). IN THIS MANNER, THE FOLLOWING WERE DEVELOPED IN EXPERIMENTS WITH ANIMALS AND RESEARCH ON HUMANS: indices of the harmful effects of neurotropic toxic substances, a change in operant behavior, a decrease in the amplitude of total electrical activity, a change in time-amplitude parameters of evoked potentials, and a decrease in post-discharge convulsion thresholds in the cortical-medial nucleus of the amygdala. Neurophysiological and neurochemical research methods have proven to be the most sensitive and informative of the methods used. These criteria and methods are recommended for determining threshold levels of various neurotropic toxic substances which pollute the atmosphere.

Animals↗

Investigation of the mechanism of action of atmospheric pollutants on the central nervous system and comparative evaluation of methods of study.

Some aspects of the mechanism of action of atmospheric pollutants (acetone, benzene, ammonia, formaldehyde, and ozone) on the central nervous system were studied by using methods of functional electroencephalography (analysis of the readjustment reaction to a rhythmic light stimulus, evoked potentials of the cerebral cortex, and determination of the photometrazol thresholds). Effects of the compounds were determined for the various structures of the cerebral cortex of experimental animals. The most sensitive structures were those which were first to associate in the reaction to toxic agents (the corticomedial nucleus of the amygdaloid complex and the olfactory bulb). EEG indices were observed which were indicative of an adverse effect (epileptoid activity in the most sensitive formations of the brain and a stable generalized stress rhythm in the neocortex and in the limbic ascending reticular system). During long-term action of toxic materials at low concentrations, changes were observed in the parameters of the primary and secondary responses of the visual evoked potential which were indicative of a disturbance of the cortical inhibition processes. This can be considered one effect of atmospheric pollutants at low concentrations. Problems of the comparative sensitivity of the various methods of studying the central nervous system are being investigated with a single compound: carbon bisulfide. In human experiments concerned with the fine coordination of measured movements such as writing and the solution of arithmetic problems, the subject-operator observed that repeated inhalation of subsensory concentrations of carbon bisulfide (0.08 mg/m3 level) disturbs the rate of execution of assigned motor processes. In tests with rats with developed instrument conditioned reflexes, it was shown that entire behavioral acts deteriorate under the effect of the same carbon bisulfide concentration. In tests on rabbits, simultaneous neurophysiological and neurochemical analyses were performed on the changes in the functional state of the central nervous system under chronic exposure to carbon bisulfide at various concentrations.

Acoustic Stimulation↗