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Biomedical subjects

A S Pushkin

Publications and source records attributed to A S Pushkin.

12 recordsLinked to original sources
PubMed1978

[Dynamics of changes in the ultrastructure of hypothalamic nerve cells in acute morphine poisoning].

In order to study the dynamics of submicroscopical changes in the paraventricular and supraoptical nuclei of the hypothalamus the authors studied with the aid of electron microscopic methods 12 white rats of the Wistar line. Such studies were performed in different periods after acute intoxication by middle toxic doses of morphine. Following 30 min after the injection the nervous cells demonstrated moderately expressed ultrastructural changes of a chromatolytical type. Chromatolysis after 60 min was increased and it was accompanied by focal destruction of the cytoplasma. After 48 hours following acute intoxication the changes of the nervous cells were characterized by a prevalent increase of the granular components, that formed the picture of a functional hyperchromatosis. These changes indicate to a tendency to rehabilitation of damaged structures.

Acute Disease↗
PubMed1977

[Quantitative characteristics of ultrastructural changes in axo-dendritic synapses under the influence of tetanus toxin].

Changes in synaptic ultrastructure of the external geniculate body (EGB) were investigated in rats when a generator of pathologically intensified excitation (GPIE) was produced in this nucleus under the influence of tetanus toxin (TT). At the period of pronounced convulsive activity (24 h after TT injection), synaptic changes were estimated electronmicroscopically and with quantitative comparison of the materials from three groups. The first group included EGB synapses where TT was injected, the second group included contralateral EGB synapses and the third included EGB from the rats injected with inactivated toxin. By means of electron optic computer "Klassimat" average amount of round, flat, anomalous and adjacent to the presynaptic membrane vesicles was measured, average relative length of the active zone, average area of the presynaptic terminal, average relative section areas of pre- and postsynaptic cytoplasm condensation were estimated. In the area of GPIE formation, under the influence of TT, the increased amount of the vesicles related to the presynaptic membrane and that of flat vesicles were statistically significant. At the same time, the synaptic terminals, by the number of vesicles, have bimodal, while the control groups have unimodal distribution.

Animals↗
PubMed1976

[New growth of interneuronal connections in the neocortex of adult rats under conditions of secondary epileptogenesis].

The synaptic organization of the parietal cortex in the zone of a chronic mirror epileptic focus was studied in rats electron microscopically. The synaptoarchitectonics was found to change as compared with control material in the mirror focus. Part of synapses were reduced due to degeneration of interhemisphere fibres. The amount of fine preterminal axons and axo-axonal contacts increased, the organization of complex synaptic conjunction grew more complicated. These data suggest possible newformation of interneuronal connections under the influence of an intensive stream of impulses from the primary focus.

Animals↗
PubMed1975

Submicroscopic changes of cortex nerve cells in chronic mirror epileptic focus in rats.

Submicroscopic changes of neurons, synapses, glial cells and some elements of capillaries were established by studying chronic mirror foci which appeared in the rat cerebral cortex after implantation of cobalt-gelatinous rods into the contralateral hemisphere. The results were compared with normal control cortex and with changes after thermocoagulation of the symmetrical contralateral cortex. It is shown that epileptogenic lesions produce a significant reduction of RNA-components, edema and vacuolization of neuronal cytoplasm, hypertrophy and proliferation of glial cells. The revealed pathological changes of the synapses were manifested by dilatation of some vesicles and the appearance of heterogenic inclusions. The characteristic features of Wallerian degeneration of callosal synapses and the reversible retrograde changes of the neurons which send their axons into the traumatized zone of the contralateral hemisphere were observed to be similar after both experimental lesions.

Animals↗