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L E Frumkina

Publications and source records attributed to L E Frumkina.

14 recordsLinked to original sources
PubMed1993

[The mechanism of the development of the synapse as the basis for its involution].

The electron microscopic investigation of human brain synaptic organization in normal aging and in ischemic heart pathology in different life periods was performed. A significant quantity of desmosome-like and mixed contacts was shown. Their ultrastructural organization was similar to that of developing synapses during prenatal ontogenesis and in newborn rats. The analysis of the experimental results suggests that an appearance of desmosome-like contacts in the human brain results from synapse involution. This is supported by the observation of formation of mixed contacts which may be a transitional stage between symmetrical or asymmetrical specialized synapse and desmosome. Thus, the mechanism of synaptic involution appears to be a mirror reflection of the mechanism of its development.

Adult↗
PubMed1993

[Changes in the configuration of the synaptic membranes in the human brain in aging and vascular pathology].

The structure of synapses in the brain of persons who had died of aging and vascular disease was studied by electron microscopy which indicated synaptic contacts with the convex and concave surface of pre- and postsynaptic membranes. There were also synapses with more complicated alterations in the configuration of synaptic membranes. The functional significance of the phenomenon is discussed in the paper. It is assumed that the alterations in the curvature of synaptic membranes are manifestation of plasticity of a synapse and they are of compensatory value.

Adult↗
PubMed1991

[Microvesicles in the developing synapses].

The sensomotor cortex and nucleus caudatus of the embryonal (14-22 days) and newborn rats have been investigated by electron microscopic method. There were described two groups of microvesicles (10-20 nm in diameter) with smooth and rough external surface. They differ from other vesicular components of the developing synapses (such as synaptic vesicles, vesicles of growing conus and other) by the minimal size, structure and localization. Microvesicles with the rough external surface are found only at that moment when the membranous specialization of the further synapse from desmosomes begins to form. They are found along the membranes of active contact zone and are correlated with the degree of differentiation of these membranes. Microvesicles with the smooth external surface are found during the all period of synaptogenesis. They are found either in presynaptic terminal freely or they are attached to presynaptic membrane where they form cluster of microvesicles and they can be found on the surface of synaptical vesicles too. In this article the functional role and genesis of microvesicles are discussed.

Animals↗
PubMed1990

[Neurofibrillary changes in the nerve tissue of humans and animals].

Electron microscopy was employed to study neurofibrillary++ alterations in some parts of the brain of man aged 73 and 83 years (physiological ageing) and 36 to 80 years (vascular pathology) as well as in the spinal ganglion of dogs at different times after ischemia. Neurofibrillary++ alterations consisting in hyperplasia of microfilaments and formation of fibrillar bundles were recorded in both cases in nerve and glial cells and in their processes whereas in the human brain, they could be also detected in the intercellular space. Experimentally, filamentous hyperplasia in neurons was the most prevalent form whose intensity was related to the time elapsed after ischemia, attaining maximum in neurons with destructive processes. In human brain, filamentous alterations were not a permanent characteristic of neurons even on ageing. The greatest pleomorphism of fibrillar alterations could be observed in the soma of glial cells, in the processes of neurons and glia. Special emphasis should be laid on fibrillar bundles demonstrable in the intercellular space of human brain. Ultrastructure of the bundles was noted to be pleomorphic, which may be determined by their inconclusive genesis. It should be noted that fibrillar alterations in human brain are variable not only from case to case but also within the range of the same age. However, they are most remarkable in elderly and senile persons.

Animals↗
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↗
PubMed1987

[Possible mechanisms of synapse formation during ontogenesis].

Electron microscopic investigation of synaptogenesis in the sensomotor cortex and in the caudate nucleus has been performed in the prenatal ontogenesis (16-22 days) and in newborn rats. The first immature synapses are demonstrated to appear beginning on the 16th day of embryogenesis. At the end of the prenatal development and especially in newborn animals desmosome-like, asymmetric and symmetric, mixed and complex forms of the synaptic contacts are revealed. As a result of the analysis performed on the ultrastructural organization of the contacts, a hypothesis explaining mechanisms of development of various elements of the synapses has been suggested. A part of the synaptic contacts of the asymmetric and symmetric types is supposed to be genetically programmed and membrane specialization of these contacts is formed earlier than synaptic vesicles appear. Other part of the synapses undergoes certain stages of differentiation before the functionally mature contact is formed. The initial stage in the synapses formation in formation of the desmosome-like junction. The second stage is appearance of synaptic vesicles in the area of this contact. The third stage includes development of pre- and postsynaptic membranous specialization and owing to this the contact acquires either asymmetric or symmetric appearance. For the ontogenetic periods investigated establishment of complex forms of the intercellular junctions (tangent, reciprocal, etc.) is specific; this evidently demonstrates certain plastic rearrangements in the synapses during the process of development.

Animals↗
PubMed1986

[Various types of non-synaptic intercellular contacts in the developing brain of the rat].

Peculiarities of ultrastructural organization and localization of early forms of avascular nonsynaptic types of junctions formed in 14-18-day-old rat embryos have been studied; cerebral structures different in their phylogenic relations (the sensomotor cortex and nucleus caudatus) are taken as an example. Five main types of nonsynaptic intercellular junctions have been revealed: desmosome-like, gap, symmetric, asymmetric and mixed junctions. They differ by their ultrastructural organization. These types of junctions make the main types of contacts: soma-somatic, dendro-somatic, dendro-dendritic, axo-somatic, axo-dendritic. Desmosomes form the greatest number of the contacts. The earliest and the most primitive are gap junctions; they, evidently, reflect functional activity of desmosome-like junctions. The mixed junctions, perhaps, reflect the developmental stages of the intercellular contacts of transition from one type of junctions into another. Localization peculiarities of the nonsynaptic intercellular contacts are demonstrated: glomerule-like formations, establishment of numerous contacts looking like a successive chain, and so on. For some other indices a longer period of intercellular contact formation in the nucleus caudatus is noted, comparing the sensomotor cortex, though the latter is a newer structural cerebral formation from the phylogenic point of view.

Animals↗
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↗
PubMed1985

[Effect of chronic alcoholic intoxication in the rat on the structural organization of the caudate nucleus in their progeny].

By means of light (Nissl and Golgi), electron microscopy, as well as using morphometry, structure of neurons and interneuronal connections of the nucleus caudatus has been studied in 21-day-old rats reproduced by chronically alcoholized parents. As demonstrated the investigations, in young rats, physically underdeveloped, there are some signs of a delayed maturation in neurons, dendrites and synapses. Certain distrophic and reparative shifts are observed in all experimental animals. The distrophic changes of neural structures in the nucleus caudatus preponderate over the reparative ones, and in the destructive course not only the neuronal body is involved, but its processes, as well. The lesions of the latter influence organization of the synaptic contacts. This is demonstrated as a sharply decreased number of synapses of the formation studied in the field of vision. The occurring disturbance in the structure of dendrites, which play an important role in the primary integration of the information received by the neuron, can cause development of certain mental disorders in children born in alcoholic families. The reparative changes in neurons and interneuronal connections revealed suppose possible reversibility of the morphological changes observed in the offspring of drunkards.

Animals↗
PubMed1978

[Qualitative-quantitative analysis of changes in rat caudate nucleus neurons during postnatal ontogenesis].

Changes of the neurons of the caudate nucleus were analyzed in rats of different age (newborn, 7-, 14-, and 30-day-old) by qualitative and quantitative methods. Complication of the structural components of the nerve cells during the early postnatal ontogenesis was shown. The process of the neuron maturation proved to be most intensive during two postnatal weeks and was practically complete by the 30th day of the postnatal period. The results suggest that at this period of ontogenesis the caudate nucleus takes part in the integral activity of the brain.

Animals↗
PubMedDate not supplied

Changes in neurons and interneural connections of the higher sections of the motor system in the progeny of alcoholized male and female rats.

We have studied the effects of long-term alcoholic intoxication of male and female rats on the structural development of the sensory motor cortex and the caudate nucleus in 21-day-old rats (their progeny). Using light microscopy and morphometry we observed a delay in the maturation of neurons and their dendrites, and also dystrophic changes in the nerve structures in the experimental animals. The morphological changes observed show that alcoholic intoxication of parents leads to negative effects on postnatal development of their progeny.

Alcoholism↗
PubMedDate not supplied

[Structural changes in caudate nucleus neurons of the progeny of rats subjected to exposure to aminazine].

The caudate nucleus neurons structure in 21-day old rattlings, whose mothers received chlorpromazine over the whole period of their pregnancy, was studied. The intracellular build-up of the caudate nucleus neurons, the structure of their dendrites and spinae were in these rattlings more perfect than in control animals. The data obtained accord well with the results of physiological observations over the activation of behavioral reactions in the test rattlings as against the control ones.

Animals↗