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Biomedical subjects

I P Usova

Publications and source records attributed to I P Usova.

15 recordsLinked to original sources
PubMed1991

[Morphofunctional analysis of structural elements of the cornea after exposure to CO2 laser].

In the dynamics of a chronic experiment and after it, the state of the cornea and blood circulation in the uveal tract were investigated, along with the morphological studies of the occipital areas of the brain (area 17) and calculations of the thermal processes in the cornea tissues. Results of the complex studies confirmed that opacification of the cornea was not induced by the damaging heat effect of the CO2-laser irradiation with the energy of illumination at 4.2 x 10(-2) Wt.cm-2 in 120 day-long period.

Animals↗
PubMed1988

[Quantitative evaluation of the cytoarchitectonic reorganization of the locus coeruleus in the brain stem under the influence of 6-hydroxydopamine].

It has been demonstrated the reorganization of structure of locus coeruleus in the animals treated intracisternally with 300 micrograms of 6-hydroxydopamine (6-OHDA) which selectively causes the lesion in catecholaminergic system using the method of quantitative estimation of the degree of uniformity and isotropy of structures. After administration of specific neurotoxin in early stages chromatolytic changes were observed in neurons which were not yet destructive but contractive for long. After injection of 6-OHDA in 36 days in the cytoarchitectonic structure were observed marked changes in uniformity and isotropy of neuron distribution within some groups in locus coeruleus versus controls.

Animals↗
PubMed1985

[Ultrastructure of cells of the lateral field of the hypothalamus of the cat after exposure to electromagnetic radiation].

Under the effect of electromagnetic radiation not any specific changes are revealed in the neural system unequivocally characterizing disturbances in its structure as a result of an excess absorption of electromagnetic energy. The ultrastructural changes revealed in the lateral fields of the cat hypothalamus are suitable for a well known scheme demonstrating the course of the pathological process, where three phases are distinguished: reactive, destructive and restorative. The pathological process develops gradually. The reactive changes in neurons and synapses, observed immediately after withdrawal of the electromagnetic action. increase during the following three months and result in coarse destructive disorders and in death of some neurons and synapses. In 6 months certain signs of restoration of the structures are observed. Under the effect of electromagnetic radiation water redistribution between the structures takes place, the sympathetic terminals loosing their fluid. Thus, certain conditions are produced for sticking together the synaptic vesicles. Possibly that deficiency of Ca++ ions contributes to it.

Animals↗
PubMed1984

[Morphological restructurings in the brain due to a decrease in the catecholamine level].

Using light and electron microscopic examinations, the authors studied various portions of the rat brain following intracysternal administration of 6-hydroxydopamine. The lowered levels of noradrenaline in the cerebral tissue and an altered ultrastructure of neurons of the catecholaminergic centres and their processes were discovered in various areas of the brain. The time-course and the pattern of these readjustments may serve as a model for the investigation of the etiopathogenesis of various mental diseases and the elaboration of the methods of their pharmacotherapy.

Animals↗
PubMed1984

[Morphologic characteristics of locus coeruleus neurons after selective chemical damage to the catecholaminergic system of the brain].

The initial part of the noradrenergic cerebral system--the locus caeruleus neurons--has been studied light and electron microscopically at various time after injection of 6- hydrodopamine (6-OHDA), a substance possessing a selective neurotoxic effect on the catecholaminergic mediatory system. Intracisternal injection of 6-OHDA (300 mcg) produces a number of reactive rearrangements in the neurons and large dendrites. Nevertheless, the death of the neural cells is not observed even by the 36th day.

Animals↗
PubMed1980

[Ultrastructure of the neurons and synapses of the posterior hypothalamic field in immune reactions].

The antigenic stimulation induces alteration of the ultrastructure of neurons, synapses and glial cells in area hypothalamic posterior of the brain of experimental animals. Swelling of mitochondria, partial or total destruction of cristae points out to the involvement of the energy apparatus of neurons and synapses. An intensive formation of antibodies is accompanied by an increase in the structural functional activity of neurons. Ultrastructural alterations of some organelles of neurones, synapses and glial cells are connected with adaptive reactions of intracellular structures and have a non-specific nature.

Animals↗
PubMed1979

[Dynamics of axonal degeneration in the neuronally isolated cerebral cortex].

The brains of 11 cats were studied after unilateral isolation of the cortex after M. M. Khananashvily (1961) by means of resection of the projection fibres connecting the cortex with subcortical formations. The character and peculiarities of axonal degeneration in the large hemisphere cortex, were investigated after Nauta and Fink--Heimer. It was found that distribution of degenerating terminals in every layer depended on the time when the material was taken for investigation. Maximal concentration of the degenerating fibres was observed 3--5--10 days after the operation, then a gradual decrease in density of degeneration in every cortical layer was observed. By the 9th month after the operation, the processes of axonal degeneration completely came to their end. The problem of retrograde and anterograde nature of the axonal degeneration in the cortex of the large hemispheres was discussed in the article and it was demonstrated that in the field 4 of the neuronally isolated cortex it is of mixed nature.

Animals↗
PubMed1977

[Changes in the dendritic organization of the neurons of the isolated visual cortex of the cat].

The cortex of one hemisphere in cats was isolated according to M.M. Khananashwili method by means of surgical section of its projection fibres which connect it with subcortical structures. In five cats of means of Nissl's method the neuronal status of different cortical layers in the field 17 was studied during long postoperative terms (from 9 months up to 2 years). In 9 cats the neurons of the same field were impregnated after Golgi-Bubenett method and studied during the same postoperative terms. Cytological investigation in the majority of neurons did not reveal any pathologic changes during different postoperative terms up to one year. In two years, slight neuronal changes were noted presented in poor staining and vacuolization of cytoplasm. As a result of deafferentation performed shortening and thickness of dendritic branching was noted, as well as decrease in the number of thorns of large pyramids in layers III, IV, and V of the isolated cortex. Dendrites and thorns in small and medium-sized pyramids in layers II, III, IV, V, and VI were preserved to a great extent. It is possible to conclude, on the fact of thorns preserving in the major number of the neurons, that the neocortex possesses an enormous intracortical connective system that is responsible for the high degree of functional neuronal activity in the isolated cortex.

Animals↗
PubMed1977

[Retrograde changes in the giant pyramids of the motor area of the isolated cortex].

Retrograde changes in the giant pyramids of the layer V in the motor area of the cortex isolated neuronally at different dates after operation were followed by Nissl method. The cortex isolation was surgically performed by sectioning projection fibres which connect the cortex with subcortical structures after M. M. Hananashvily method (1961). Characteristic retrograde changes appeared in the giant pyramids on the third postoperative day: moderate swelling of cellular bodies, chromatolysis and nuclear displacement towards the periphery. In the following days the retrograde changes progressed rapidly and by the 10th day resulted in a partial destruction of the giant pyramids. One month later in the layer V, only separate cellular shadows were visible; from one month to one year period the giant pyramids in the layer V disappeared completely. Neurons of other layers in this area, as well as small and middle size neurons of the layer V are preserved and show no signs of pathological changes.

Animals↗
PubMedDate not supplied

[Permissible level of laser radiation of wavelength 10.6 microns].

In a four-month experiment with 102 male rabbits and 42 HRS/U mice and 30 days after termination thereof, study was made of local and general response of an organism to the effect of laser radiation (10.6 microns wave length and energy exposition 1/7 of the threshold). The radiation tolerance level was estimated.

Animals↗
PubMedDate not supplied

[Morphofunctional characteristics of the associative region of the cerebral cortex in experimental neuroses in the dog].

Ultrastructure of neurones and synapses of the cortical associative area of dogs has been studied under conditions of experimental neuroses caused by prolonged informational loads with constant time deficit and high motivational signals significance. Analysis of subcellular reorganization of a number of neuronal and synaptic organelles showed the degenerative changes of afferent conducting systems in various neuropil parts leading to the falling out of definite neuronal groups from stable functional connections and to the disturbance of intracortical interrelations. In the cortex simultaneously with destructive processes, are developing intracellular compensatory-adaptive reactions.

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