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Biomedical subjects

L B Verbitskaia

Publications and source records attributed to L B Verbitskaia.

At least 19 recordsLinked to original sources
PubMed1989

[Effect of vascular factors and aging on the ultrastructure of neurons of the human cerebral cortex].

Neuronal ultrastructure of the frontal and temporal cerebral cortex has been studied in persons 36-, 39-, 50-, 70-year-old, died from the ischemic heart disease and 73-, 83-year-old, whose deaths are not connected with vascular pathology. The neurons can be divided into several groups, depending on osmiophilic degree of their nucleus and cytoplasm: I--electron-light, II--electron-opaque, III--with dark nucleus and light cytoplasm and IV--with light nucleus and dark cytoplasm. The protein-synthesizing apparatus (PSA) is subjected to the earliest and most essential disorders. Its changes in the I group of neurons at the age of 36-50 years are mainly of compensatory-adaptive character, while at the age of 73 and 83 years the dystrophic changes of the PSA result in hollowness of the cell, that evidently makes the base of the cell ageing mechanism. Presence of electron opaque neurons is not a sign of ageing, and depends on various pathology, in the given case on the ischemic heart disease, that causes certain vascular disorders in the brain. Variability of the ultrastructures of the electron opaque neurons and essential changes of some part of them, observed in the brain of the 72-year-old man confirm that the vascular factor is an important one in pathology of neurons. Dependence of lipofuscin appearance in neurons on the manifestation degree of the pathological process and ageing in them is discussed.

Adult↗
PubMed1988

[Compensatory-adaptive restructuring of the aging human brain].

In semithin sections of the frontal and temporal cortex from the human brains the compensatory-adaptive changes of neurons and glia were studied. The specimens were obtained from 2 physiologically aged subjects, 7 cases of senile dementia, 2 cases of Alzheimer disease. Alongside with the destructive changes in nerve and glial cells, the compensatory-adaptive processes were detected in aging brains, generally characteristic of the physiologic aging: the nucleolus shift to the nucleus periphery; redistribution of the nuclear chromatin, nuclear membrane invagination; closer attraction of the organelles to nuclear membrane as destruction increased; assembling the neural and glial cells; establishment of the desmosome-like glioglial contacts.

Adaptation, Physiological↗
PubMed1988

[Intracellular regeneration of neurons in the rat lateral hypothalamic area of the brain after resumption of food intake].

Electron microscopy was used to explore changes in intracellular regeneration processes in neurons of the anterior, medial and posterior parts of the lateral hypothalamus area (LHA) of rats at various time (10, 20, 30, 50 and 70 days) after resumption of food perception. Ultrastructural changes observed during 7 days of food deprivation in intact neurons were of a reversible character. Recovery processes initially appeared and finished earlier in the neurons of medial (day 30) and anterior (day 50) parts of the LHA, in the posterior part of LHA the normalization of the neuronal structure was slower and was over only by the 70th day after the resumption of food reception. The above data are both of theoretical and practical importance, serving as a base for the study of directed treatment of diseases caused by hunger.

Animals↗
PubMed1987

[Synaptic changes in cortical and subcortical brain formations in old rats].

Electron microscopy was used to study structural changes of synapses in sensorimotor, parietal, limbic cortical areas, hippocamp, blue spot and hypothalamus of old Wistar rats, aged 28-30 months. Polymorphism of ultrastructural changes in neuronal and synapse processes and individual variability of these shifts in the brain of old rats have been revealed. The predominant damage of post-synaptic synapse components with ageing is demonstrated. Along with dystrophic and destructive changes in pre- and post-synaptic parts of the contact, signs of compensatory adaptive resettings in inter-neuronal links have been detected.

Aging↗
PubMed1986

[Changes in neurons of the cerebral cortex in senile dementia].

Using light and electron microscopy, the frontal, temporal and parietal cortical neurons were studied in 10 cases of senile dementia. It was found that along with general age-specific disorders of the ultrastructure of neurons and glial cells (varying degrees of chromatolysis, accumulation of lipofuscin, mitochondrial changes) the examination revealed ultrastructural shifts which might be characteristic of senile dementia. They include rearrangement of nuclear chromatin, destruction of nuclear membrane with the subsequent vacuolization of the nucleus and karyolysis, the appearance of polymorphic fibrillar inclusions in the cytoplasm of neurons and gliocytes, as well as the disappearance of subsuperficial cysterns. Destructive processes were also attended by signs of compensatory changes, i.e. displacement of the nucleolus to the nuclear periphery, the development of desmosomophide contacts at the site of the neuron and glial satellite cell contact, the grouping of cells, and frequent fusion of the adjacent cellular elements.

Aged↗
PubMed1986

[Ultrastructural changes in the dendrites during aging].

Dendrite ultrastructure was studied in different brain areas of old rats, aged 28-30 months. Different ultrastructural forms of the reactive and destructive processes in the dendrites, irregularity of their pathomorphological changes with ageing and greater destruction of large dendrites, as compared to small ones are demonstrated.

Aging↗
PubMed1984

[Ultrastructure of neurons and synapses of the lateral hypothalamic area in the rat].

Ultrastructural organization of the lateral hypothalamic area (LHA) has been studied in Wistar rats. Structural peculiarities of neurons and interneuronal connections in the anterior, middle and posterior parts of the LHA have been demonstrated. In the anterior and middle parts, neurons of middle size (17-22 mcm) make the most of the cellular population; large neurons (35-50 mcm) predominate in the posterior part of the LHA. Small cells are diffusely distributed in all the parts. Two types of axons are defined: axons of the I type--with round light, and some of them, with large granular synaptic vesicles; axons of the II type contain smaller and polymorphous light synaptic vesicles. The axons form axodendritic and axosomatic synapses. The former predominate in all parts of the LHA. The axons of the I type form, mainly, asymmetrical, and the axons of the II type--symmetrical contacts. Most of the synapses are formed by the axons of the I type, overwhelmed majority of the synapses are axodendritic. Differences in localization and in distribution of the axodendritic synapses in different parts of the LHA are revealed. In the anterior part of the LHA the axodendritic synapses form synaptic muffs around large and middle dendrites, and more seldom around small and spine-shaped processes of the dendrites. In the middle and posterior parts of the LHA no synaptic muffs are revealed.

Animals↗
PubMed1984

[Changes in the hypothalamic ultrastructure during aging].

Changes in the ultrastructure of neurons and synapses of the paraventricular nucleus of the hypothalamus were studied in old rats. The time-course of the pathomorphological alterations was shown. Dendrites, particularly those of medium size, were found to be especially vulnerable. The first signs of ultrastructural changes in neurons were shown in mitochondria. Although chromatolytic changes predominated in the majority of the hypothalamic neurons, hyperchronic alterations could also be observed. The nucleoli and nucleoliform formations in the cytoplasm proved the most "stable" components of neurons.

Aging↗
PubMed1984

[Ultrastructural changes in the neurons and interneuronal connections of the lateral hypothalamic area in rats at different times of food deprivation].

Changes in bodies of neurons, their processes and synapses in the lateral hypothalamic area (LHA) in rats at various time (1, 3, 5 and 7 days) of food deprivation have been studied electron microscopically. The changes in the posterior part of the LHA are the first and in the middle part of the LHA are the last to appear. The number of altered bodies of the neurons, their processes, synapses and severity of their injury during all the time of fasting is the greatest in the posterior and the least in the middle part of the LHA. The character of the ultrastructural changes is unitypical everywhere. Dendrites, especially those of middle and large size are the first to be injured. Their changes immediately acquire destructive character (vacuolization of dendroplasm, appearance of complex membranous bodies, swelling and destruction od microtubules and neurofilaments). One of peculiar features of the destructive changes of the neuronal processes and synapses is invagination of adjoining areas of axons and synapses into the dendrite. In the bodies of the neurons the changes appear later than in the dendrites and at first they are of functional character and only beginning from the 5th day of fasting certain signs of destructive disorders are noted. With increasing time of fasting, the injury is growing more severe and a greater and a greater number of the neuronal bodies, processes and synapses are involved into the pathological process.

Animals↗
PubMed1983

[Changes in the dendrites of the rat lateral hypothalamic region during food deprivation].

Electron microscopy was used to explore ultrastructural changes in the lateral hypothalamic area (LHA) of rats 1, 3, 5 and 7 days after food deprivation. Special attention was paid to studies on changes in LHA dendrites which carry out receptive function. The dendrites were shown to be the most vulnerable and to be affected earlier than other components of neurons (somas, axons). The time course of pathomorphological changes in the dendrites, namely from initial to gross destructive ones, was specified. The characteristic changes in the dendrites included invagination into the dendritic cytoplasm of adjacent structures, mostly axons, with destructive changes in the area of invaginated parts. Invagination could be observed since the third day and was the most demonstrable on the 7th day of food deprivation. The possible mechanisms of such invaginations are discussed.

Animals↗
PubMed1982

[Reorganization of the synapsoarchitectonics of the rat red nucleus after destruction of the motor cortex of the cerebral hemispheres].

In 50 white rats the red nucleus synaptic organization both normal and at various time (1, 2, 3, 5, 7, 10, 14, 21, 30 and 60 days) after destruction of the cerebral cortical motor area has been studied electron microscopically. Peculiarities of the synaptic organization in the parvicellular and macrocellular parts of the red nucleus and reorganization of the synapsoarchitectonics are demonstrated after the motor cortex has been destroyed. During the first 2-3 weeks after the destruction, certain degenerative changes are mainly noted in the parvicellular area of the red nucleus. Small axonal terminals with round light synaptic vesicles are subjected to degeneration according to the dark type, they form asymmetric synapses on small, sometimes--on middle dentritic branches. On the 21-30th day, together with the degenerative changes, plastic reorganization of the red nucleus synapsoarchitectonics both in the parvicellular area and in the macrocellular areas adjoining the latter are noted. Evidently, this reorganization takes place at the expense of the cerebello-rubral fibres. The participation of the inter-posito-rubral fibres terminating in the macrocellular part of the red nucleus is definitely stated. Their large terminals form synapses on the soma and the proximal dendrites of the giant and large neurons. It is from these axonal terminals that the growth cones take their origin on the 21st day after the destruction of the motor cortex. Later (on the 30th and the 60th day) new processes and synapses appear in the parvicellular part of the red nucleus. Some dendrites undergo certain changes. Dendro-dendritic synapses and complex synaptic contacts appear.

Animals↗
PubMed1982

[Ultrastructural changes in the brains of rats after sustaining acute emotional stress].

The ultrastructure of the neurones and synapses of the parietal area of the cortex and reticular formation of the brain of rats was studied after emotional stress induced by 2-hour immobilization, as well as 1 and 24 hours after discontinuance of immobilization. Two types of ultrastructural changes were revealed. Some of the changes were reversible and functional in nature and were largely pertinent to the alterations on the cytoplasma part, with these alterations being appreciably reduced 24 hours after the discontinuance of immobilization. The other ones (vacuolization of neuronal nuclei and marked changes in the synapses) were more pronounced and resistant and were seen 24 hours after the immobilization was discontinued. It is suggested that stable changes that do not disappear 24 hours after the immobilization stress might form the pathomorphological basis for the clinical syndromes of cerebrovisceral disorders that develop during long-term periods after the stress.

Animals↗
PubMed1980

[Location of neurons giving rise to certain descending fiber systems in the sensomotor and orbitofrontal cortex].

By means of the horseradish peroxidase (HP) retrograde axonal transport method localization of HP-labelled neurons in the forebrain cortex making projections on some somatic (motor and sensory) spinal and truncal centers, as well as on the retucular formation, substantia nigra and hypothalamus has been studied. Certain peculiarities in localization of the neurons giving origin to various fibre systems in the forebrain cortex have been revealed. Differences are especially noticeable in the area of sulcus chiasmaticus. Only when HP is infected into the spinal cord there is nearly no labelled neurons in the orbital-frontal cortex, while if the enzyme is injected into other structures studied HP-positive cells are revealed in this cortical area. Numerous labelled neurons are noted in the orbital-frontal cortex when HP is injected into the reticular formation and nuclei of the midbrain--the red nucleus and substantia nigra. In the lateal sulcus area HP-positive neurons are revealed when the enzyme is injected into the spinal cord and substantia nigra. Neurons giving origin to the fibre systems running to the spinal cord and to a number of subcortical formations are situated in the layer V. Cortico-hypothalamic neurons, that localized not only in the layer V, but also in the layers III--IV of the frontal cortex and in the layer VI of the orbital cortex--in the presylvian fissure are, make the exception to the rule.

Animals↗
PubMed1978

[Changes in neurons of a spinal ganglion culture during chronic exposure to increasing concentrations of morphine].

On the model of spinal ganglion cultures in mice by means of a light and electron microscopy the authors studied neuron changes in chronic influence of increasing concentrations of morphine. These studies demonstrated changes in most of the cytoplasmatic organells: changes in the granular and agranular reticulum; an appearance of a large amount of small vesicles in the cytoplasma and lysosome; changes of the mitochondria (partial vacuolization of the crysts and appearance of a big amount of small mitochondria); a large amount of myelin-like structures; changes of the nuclear membranes; nucleoli and an increased amount of ribosomes.

Animals↗
PubMed1978

[Postnatal histogenesis and cell proliferation in the parietal region of mouse neocortex under normal conditions and following brain injury].

Postnatal histogenesis of the parietal area of the neocortex and proliferative capacity in it of the main cell types were studied in mice under normal conditions and in stab wound of the brain by analysing 3H-thymidine-labeled cells on semithin sections. As revealed, microneurons failed to form in the parietal cortex of mice during the postnatal period either by migration of undifferentiated cells or by proliferation. Injury of the right hemisphere did not cause any change in the way of histogenetic transformations of cells migrating into the cortex of the parietal area in the direction of their differentiation into microneurons.

Animals↗
PubMed1977

[Interaction of fibers from the retina and visual region of the cortex in several subcortical visual formations of rats].

The medial nucleus of the optic tract, the ventral lateral geniculate nucleus and the superior colliculus have been studied using the light (Nissl, Golgi, Viktorov) and electron microscopic methods in normal rats and in rats which survived for different periods after enucleation or occipital cortical lesions. Data were obtained on differences in terminal patterns of the afferent pathways. The study of the neuronal and synaptic organization of subcortical visual centers showed the distinctions and correlation between the complexity of neuronal and synaptic organization. Three types of interrelations between the optic and cortical pathways on the efferent neurons of the investigated structures are suggested.

Animals↗