Biomedical subjects

I I Semenchenko

Publications and source records attributed to I I Semenchenko.

6 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↗

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

[Ultrastructural changes in the neurons of the sensorimotor cortex in rats under prolonged hypokinesia].

The authors studied the neuronal ultrastructure of the sensorimotor cortex of rats exposed to 90 days of hypokinesia and at different times after its withdrawal. During prolonged restriction of motor activity, dystrophic changes seen in the cortical neurons were most demonstrable. During the first week of the posthypokinetic period, the degree of dystrophic lesions was reduced and the signs of intracellular regeneration were fairly conspicuous. Three weeks after hypokinesia withdrawal the ultrastructure of most neurons returned to normal, with the structure abnormalities being still observed in individual cells.

Animals↗