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Biomedical subjects

L S Onishchenko

Publications and source records attributed to L S Onishchenko.

10 recordsLinked to original sources
PubMed2000

Morphological changes in the skin during experimental allergic encephalomyelitis and multiple sclerosis: bases for new diagnostic test.

Skin specimen from the medial malleolar area of patients with multiple sclerosis and guinea pigs with experimental allergic encephalomyelitis were examined by light and electron microscopy. Demyelination, inflammation, and dystrophic changes in peripheral nerves and skin correlating with clinical manifestations were revealed in both sclerosis and encephalomyelitis. Maximum changes were revealed in nerve-associated cells (Merkel cells), Langerhans cells reflecting inflammation intensity, and fibroblasts responsible for nerve integrity and resistance against external stimuli.

Adult↗
PubMed1999

[Mitochondrial megaconia and pleioconia in the rat brain as possible and adaptive reactions in lethal radiation and radio-modified injuries].

Electron microscopic study of sensomotor area of brain and cerebellar cortex was conducted in 38 outbred albino rats, following 200 Gy irradiation including that combined with preceding effect of hypoxia or 48 hrs long active vigilance. Mitochondrial megaconia and pleioconia were found 4 hrs after the irradiation in neuronal cytoplasm and axoplasm of neuropil unmyelinated and myelinated fibres. These processes were more significant after radio-modified injuries. It may be suggested that mitochondrial megaconia and pleioconia are adaptive reactions to de-energization following the action of superpowerful extreme factors.

Adaptation, Physiological↗
PubMed1996

[A morphofunctional analysis of the nuclear apparatus of the nonapeptidergic neurosecretory cells in the vertebrate hypothalamus].

A vast comparative material obtained on fishes, amphibians and mammals has been analysed using ecological and experimental histophysiological approaches. The structural organization of the nuclear apparatus of nonapeptidergic neurosecretory cells, especially in the lower vertebrates has been clearly shown to differ from that of the classic neurones. Morphometrical characteristics of nonapeptidergic neurosecretory cells of hypothalamic centers can be used for a reliable evaluation of their functional conditions. A high intensity of protein metabolism in nonapeptidergic cells of magnocellular hypothalamic centers leads to a bigger nucleolus/nucleus relation for these cells in parvocellular centers. All this proves the necessity of the morpho-functional analysis of nuclear apparatus of neurosecretory cells.

Amphibians↗
PubMed1993

[A method for preparing a monolayer of frog brain cells for the cytophotometric determination of their DNA content].

An improved method for the squashing of the brain cells permitting a good preservation of cell nuclei and their subsequent quantitative cytophotometric evaluation is presented. By this method a monolayer of the brain cells can be easily obtained. The method was tested in cytophotometric study of the DNA content in the Feulgen stained cells of the frog hypothalamic preoptic area. The proposed method can be used for the quantitative evaluation of different histochemical reactions in the brain cells.

Animals↗
PubMed1983

[Autoradiographic study of the proliferative activity of the preoptic recess ependyma in yearling and juvenile common frogs].

Proliferative activity of the ependyma, lining the recessus praeopticus in juvenile frogs was studied with 3H-thymidine radioautography. Usually much more pronounced proliferation of ependymal cells occurred in the preoptic region in one year old frogs as compared with two year old ones. It can be concluded that in the former animals the migration of postmitotic labeled cells into the subependymal zone of the recessus preoptic area is significantly more intense. By the 30th day after multiple isotope injections some newly formed neurosecretory cells with labeled nuclei were found in the 1-5 cellular position of the recessus praeopticus subependymal zone. It is postulated that in juvenile frogs the ependyma of lateral wall of recessus praeopticus is probably a source ("cambium"), from which some young neurosecretory cells may originate.

Animals↗
PubMed1983

[Cytophotometric study of the DNA content in the cells of the preoptic area of the hypothalamus in hibernating common frogs].

The DNA content in the squashed Feulgen stained cells of the hypothalamic preoptic region in wintering adult and juvenile frogs was measured cytophotometrically. The vast majority of hypothalamic cells studied showed diploid DNA contents. Only 0.9% of tetraploid cells (4c and 2c X 2 cells) was found in this region, both in adult and juvenile frogs. The incidence of tetraploid hypothalamic cells varied among the individuals studied. In some adult frogs as well as in some juveniles no tetraploid cells were detected. The data obtained do not confirm the age related increase in the mean DNA content in frog's hypothalamic cells population.

Animals↗
PubMedDate not supplied

[Comparative analysis of the effect of magnetic fields of varying intensity under experimental conditions].

Three series of experiments on mature male and female non-inbred rats weighing 160-200 g with chronic vertebrobasilar circulation disorders (CVCD) and chronic myeloischemia (CMI) of the lumbosacral segments have been performed to assess efficiency of treatment with various physical methods. It was found that measurement of ribosomal cystrone activity by bone marrow preparations staining with silver salts is a simple and fast method of estimation of cell proliferation in the cystrones in exposure to different therapeutic factors, and of prediction of the disease outcome. Combined magnetic and electric therapy is more effective than monotherapy with sinusoidal modulated currents or modulated currents. This is explained by synergism of the therapeutic factors.

Animals↗
PubMedDate not supplied

[New morphological data on multiple sclerosis].

The brain from 6 patients who died of multiple sclerosis was studied with MR tomography (MRT), macroscopy, light (CD 3, CD 20, LCA antigens) and electron microscopy (EM). Typical foci of demyelinization (plaques) were found in all cases. Alterations of brain arteries were found particularly in arteries of narrow lumen--with disturbance or even absence of elastin and muscle layer. Up to 30% of the vessels were surrounded by microcavities. Perivascular infiltrates consisting primarily of T lymphocytes were observed around the vessels (up to 70% of all vessels). This indicates the importance of vascular changes in the disease pathogenesis. Four variants of demyelinization (plaques) are distinguished depending on the degree of destruction of myelin, axons and glia. Two types of cells were found in the plaques with most pronounced changes: astrocytes and newly formed oligodendrocytes. Classification of plaques is suggested.

Adolescent↗