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D Deleva

Publications and source records attributed to D Deleva.

13 recordsLinked to original sources
PubMed2005

[Blood serum of patients with secondary progressive multiple sclerosis changes neuron electric activity].

An effect of 20% blood serum estimated by the changes of background and excited spike activity of Retzius' neuron by Hirudo medicinalis, which does not contain myelin, has been studied in 2 groups of patients. The first group comprised patients with serum, containing antibodies to gangliosides, and the second one--patients without such antibodies. Incubation of Reitzius neurons in the serum with GM1-antibodies within 40 min resulted in the change of spike form, increase of cell stimulation threshold by average 20%, reduction of the frequency of spontaneous impulse activity by average 28%, decrease of the spikes number in response to the lower frequency (0.5 Hz) synaptic stimulation and inhibition of adaptation to the high frequency (10 Hz) stimulation. The use of the serum without GM1-antibodies caused a different change of the spike form and increased the stimulation threshold by 8% and sparser background impulse activity of the neuron by 40%. During low frequency synaptic activation of the neuron (0.5%), there was sensitivity disturbance and inhibition of the electric response to the high frequency stimulation. The results suggest that neuron injuries in multiple sclerosis may develop before morphological appearances of myelin lesions.

Adult↗
PubMed2004

Analysis of the effects of antibodies to gangliosides on the electrical activity of Retzius neurons in the leech and on the functional activity of influx sodium current channels.

The effects of anti-ganglioside antibodies on the functional states of two types of influx Na+ current channels were studied. Experiments used 20% anti-ganglioside antiserum prepared by standard methods by immunizing rabbits with total bovine brain gangliosides. These experiments showed that incubation of neurons in physiological saline containing antiserum induced discordance in the operation of the two types of influx current Na+ channels responsible for spike generation. This reaction was found to be associated with the slowed rate of activation of TTX-sensitive Na+ channels. Synaptic stimulation of cells in the presence of antiserum induced blockade of TTX-insensitive influx Na+ current channels. High-frequency synaptic activation of cells (10 Hz) showed that apart from blockade of TTX-insensitive Na+ channels, anti-ganglioside antibodies prevented plastic rearrangements in the gate system of TTX-sensitive Na+ channels. This resulted in impairment of the development of the acclimation process - the response of the neuron to high-frequency stimulation seen in normal conditions.

Animals↗
PubMed2003

[Effect of the antibodies to gangliosides on the Retzius neuron electrical activity and the functional activity of sodium channels for incoming current in leech].

In the present study, the effect of antibodies to gangliosides on the Retzius neurons of the leech was investigated to study the spike activity and the functional activity of the Na-channels which generate the spike. A forty-minute incubation of the Retzius neurons in a 20% solution of antiganglioside serum in a Ringer solution provoked appearance of a double spike (a spike with two parts) connected with a decrease of the speed of the activation of the tetrodotoxin (TTX)-sensitive Nachannels. The high frequency synaptic activation of the neuron (10 Hz during 10 minutes) under the plasticity exchange of the gate system of the TTX-sensitive Na-channels. As a result of this, there was a disturbance of the habituation of the Retzius neuron to the high-frequency stimulation.

Action Potentials↗
PubMed2002

[Axonal reaction precedes demyelination in experimental models of multiple sclerosis].

Taking into consideration that myelin phospholipids may be partially synthesized in neuronal bodies, while neurilemma readily reacts with antibodies against gangliosides by changing the properties of membrane ionic channels, the attempt was made to test the proposed assumption of the early axonal reaction in demyelinating processes in experimental models of multiple sclerosis. The models of chronic allergic encephalomyelitis in Lewis rats injected with homogenate of highly purified myelin or total brain gangliosides were used. First signs of demyelination (the destruction of intermediate dense lines) were demonstrated in the inner layers of myelin close to axon and were shown to develop synchronously with the aggregation of filamentous-tubular material in the neuroplasm. These changes are associated with significant shift of the ratio of myelin sheath thickness to axonal diameter (from 1:7-1:3 to 2:1-3:1). This swelling of myelin seems to be caused by neuroplasmic proteins aggregation, that must be accompanied by the drop in oncotic pressure and the separation of loosely-bound water fraction that may be assimilated by myelin. At light microscopic level the increase of myelin thickness is clearly observed that is in exact correspondence with the decrease in axonal diameter. The process starts with the exfoliation and swelling of the nodes of Ranvier and the incisures of myelin, which fuse after elongation, that corresponds to the total disintegration of myelin with the preservation of continuity of axon which appears to be harshly shrunken.

Animals↗
PubMed2001

Serum ganglioside patterns in multiple sclerosis.

The relative distribution of gangliosides was determined in the serum of 37 patients with multiple sclerosis (MS) and of 30 healthy subjects. There was a significant increase of GM1 and GD1a, and a decrease of GM3 proportion in the serum of relapsing-remitting MS patients (RRMS) during their first MS attack. The RRMS patients in relapse with a long duration of the disease had a significant decrease of GM1 and an increase of GD1a portion in the serum. An increase of GD1a, one of the major brain neuron ganglioside fraction, suggested the neuron injury in the early and with a long duration RRMS. The finding of an increase of GM1, the main human myelin ganglioside, during the first MS attack in RRMS patients confirms previous evidence for the possible involvement of gangliosides in the early pathological course of demyelination in MS.

G(M1) Ganglioside↗
PubMed1998

Ganglioside changes in brain in chronic relapsing experimental allergic encephalomyelitis induced in the Lewis rat.

Chronic relapsing experimental allergic encephalomyelitis (CREAE) was induced in Lewis rats by inoculation with guinea-pig myelin and complete Freund's adjuvant followed by treatment with low-dose cyclosporin A. Rats were sacrificed at different phases of the disease (just before the onset of clinical signs, during the first clinical episode of CREAE and during the first recovery). Gangliosides were extracted from the brain, analysed after purification by HPTLC fractionation and quantified densitometrically. An increase of GM1, the main rat myelin ganglioside, and a decrease of GT1b, suggested to play a role in mediating the interactions between oligodendroglia and axons, were observed during the development of the CREAE. These findings indicating significant ganglioside changes in CREAE give further support to the concept concerning the involvement of gangliosides in autoimmune demyelination.

Animals↗
PubMed1997

Ganglioside spinal cord changes in chronic relapsing experimental allergic encephalomyelitis induced in the Lewis rats.

Chronic relapsing experimental allergic encephalomyelitis (CREAE) was induced in Lewis rats by inoculation with guinea-pig myelin and complete Freund's adjuvant followed by treatment with low-dose cyclosporin A. Rats were sacrified at different phases of the disease (just before the onset of clinical signs, during the first clinical episode of CREAE and during the first recovery). Gangliosides were extracted from the spinal cord, analysed after purification by two-dimensional chromatography and quantified densitometrically. An increase of GM 1, the main rat myelin ganglioside, and a decrease of GT1b, suggested to play a role in mediating the interactions between oligodendroglia and axons, were observed during the development of the CREAE. These findings indicating significant ganglioside changes in CREAE give further support to the concept concerning the involvement of gangliosides in autoimmune demyelination.

Animals↗
PubMed1997

[Chronic relapsing experimental allergic encephalomyelitis in Lewis rats as a model of multiple sclerosis].

Chronic relapsing experimental allergic encephalomyelitis (CR EAE) was induced in Lewis rats by inoculation with guinea-pig myelin and complete Freund's aduvant followed by treatment with low dose cyclosporin A. Histological, histochemical and electron microscopic studies of the lesions during the first and the second clinical episodes, as well as during the first and the second remissions, revealed inflammation, prominent demyelination, remyelination and gliosis in the central nervous system (CNS). This model of CR EAE in the Lewis rats may be a useful model for multiple sclerosis.

Animals↗