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Biomedical subjects

I M Gel'fand

Publications and source records attributed to I M Gel'fand.

At least 19 recordsLinked to original sources
PubMed1992

[The role of intermediate filaments in forming cellular processes induced in fibroblasts by the tumor promoter TPA].

A tumor promoter phorbol 12-myristate 13-acetate (PMA) induces characteristic reversible changes in the cell shape in certain fibroblastic lines. This reaction to PMA may be regarded as a prototype of reorganizations involving formation of stable cytoplasmic processes. Two specific drugs, Taxol and Colcemid, were used to study the role of microtubules and vimentin-containing intermediate filaments (IF) in the development of PMA-induced reorganizations. A short (I h) exposure to PMA induced formation of processes in the control cells rather than in the Colcemid treated cells having depolymerized microtubules and the IF that collapsed around the nucleus. A longer (3-4 h) exposure to PMA of the colcemid-treated cells induced a partial reversal of the IF collapse; those parts of peripheral lamellae that contained IF were transformed into narrow noncontractile processes. It is suggested that the local interaction of the IF with the actin system is an essential step in the formation of processes from lamellae.

Actins↗
PubMed1987

[Growth of neurites and formation of connections in cultures of pteropodial mollusc neurons].

Dissociated neurons from the brain of pteropodial mollusc were cultivated in a 25% Leibovitz medium containing 2% of calf serum. Neurite outgrowth was observed in 1-30% of the neurons. It was maximum during the first 3 days. Neurite length reached 300 microns. Membrane potential of neurons was 40-60 mV; they generated single spikes or bursts of impulses. Intercellular connections were tested on the 3-4th days in 70 pairs of neurons with neurites overlapped. Electrical connections between the cells were observed in 20% of the pairs tested, and in 6% of pairs stimulation of one of the neurons evoked an inhibitory postsynaptic potential in the other.

Animals↗
PubMed1987

[Changes in the form and cytoskeleton of cultured fibroblasts as affected by 12-tetradecanoylphorbol-13-acetate].

A new type of reorganization of cytoskeleton induced by 12-o-tetradecanoyl-phorbol-13-acetate motility: division of the cell into an actin-rich active part and stable processes with numerous microtubules. Such a phenomenon was observed under a short-term influence of TPA on different lines of cultured fibroblasts: NRK, Balb/C 3T3, C-103, C-84, CAK-7. The effect of TPA was reversible and suppressed by cytochalasin B and colcemid. TPA is supposed to induce changes in the interaction between actin cortex and microtubule system.

Actin Cytoskeleton↗
PubMed1987

[Migration of the nucleus and cytoplasm along the pseudopodium of the differentiated neuroblastoma cell].

Motility of neuroblastoma cells in the culture of cell line C-1300, clone N-18-A was investigated microcinematographically. In the course of morphological differentiation of the cells, after cytochalasin B treatment (1.8 mkg/ml for 24 hours), in some differentiated cells a special type of movement of the cytoplasmic mass together with the nucleus along elongated pseudopodia was detected. Such a type of movement has never been described. Sometimes, a shift in the nucleus position resulted in the complete change or reversion of cell polarity. The phenomenon of cell nucleus displacement relative to the cell configuration or reversion of the cell polarity can possibly play an important functional role for neural cells.

Animals↗
PubMed1986

[Effect of the locomotor system of the pedal ganglia of the pteropodial mollusk on anatomically isolated neurons].

The isolated pedal ganglia of the pteropodial mollusc Clione limacina generate the locomotor activity. In 30% of the pedal ganglion preparations, the locomotor rhythm was not regular, i. e. the locomotor generator worked in "bursts". These "locomotor bursts" were caused by spontaneous activations of command neurons located in the pedal ganglia. Single neurons were extracted from such preparations with an intracellular microelectrode and then their somas were put into the initial place between the ganglion cells. 25% of the isolated neurons (9 out of 35) renewed the "locomotor bursts"-related changes in the activity after the insertion into the ganglion. Neurons, originally excited during "bursts", continued to be excited after isolation, while inhibited neurons continued to be inhibited. It follows, therefore, that the command neurons can act on the target cells in the absence of morphological synapses.

Action Potentials↗
PubMed1985

[Regeneration of neurons of the pedal ganglion of the pteropodal mollusk Clione limacina].

In pedal ganglia of mollusc Clione limacina the growth of axons was studied in motoneurons and interneurons after transections of the wing nerve or of the pedal comissure. Neurons were stained by Lucifer Yellow. In motoneurons, neurites grown both from the transected end of the axon and from the neuron soma spread to all nerve trunks of ipsi- and contralateral ganglia. After nerve transection in the whole mollusc, wing movements restored 10 days later. In interneurons, neurites branched within the pedal ganglion or spread into cerebral ganglia but they did not extend out peripheral nerve trunks. Thus, the patterns of neurite sprouting in moto- and interneurons are different.

Animals↗
PubMed1984

[Morpho-clinical variants of chronic glomerulonephritis and their significance for the evaluation of the severity of the disease].

The study of the morphological, clinical and functional manifestations of compensated chronic glomerulonephritis (CGN) in 317 patients revealed the advantage of the morphoclinical variants as compared to the morphological types for the evaluation of the gravity and prognosis of the disease. The morphoclinical variant means the combination of the morphological and clinical types. It was found that the morphoclinical variants of CGN determine the probability of the tubulointerstitial component, which deteriorates the prognosis of the disease more precisely than its morphological types. Renal dysfunction is more closely connected with the morphoclinal variant of CGN than with the morphological type. The data obtained are in favour of developing a morphoclinical classification of CGN on the basis of the morphoclinical variants of the disease.

Adolescent↗
PubMed1983

[Predicting the recurrence of hemorrhage in patients with peptic ulcer].

In order to prognoze recurrent bleedings during the nearest time after admission to the hospital the authors have analyzed the most frequently used objective data on patients with gastro-duodenal hemorrhages (the activity and intensity of bleeding, size and character of the ulcer, duration and severity of blood loss). A rule for prognozing recurrent bleedings is proposed.

Hemostatic Techniques↗
PubMed1983

[Selection of the information for solving medical diagnostic problems with "diagnostic games" (the example of predicting the time of sinus rhythm maintenance after eliminating atrial fibrillation)].

A new method is proposed for data selection with respect to solving medical diagnosis problems. It reduces the scope of information, leaving for further processing only the facts the physician actually needs for problem-solving. The protocols of "diagnostic games" reflect the physician's mental process and can be used in the development of a physician model.

Atrial Fibrillation↗
PubMed1983

[Differentiation of neuroblastoma cells caused by cytochalasin B].

The action of cytochalasin B (CB) on the differentiation of cultured neuroblastoma cells has been studied. CB treatment (1.8 micrograms/ml for 3 days) blocked cytokinesis, leading to the multinucleation of neuroblastoma cells. The replacement of medium with CB by standard medium without CB led to the improvement of cell spreading on the substrate and to the appearance of 43.7 +/- 4.1% of morphologically differentiated cells. 4.7 +/- 0.6% of differentiated cells formed in CB-untreated control cultures. Thus, incubation with CB followed by the agent removal from the medium induced the differentiation of neuroblastoma cells. A possible role of multinucleation in this process is discussed.

Animals↗
PubMed1983

[Prognosis of ventricular arrhythmias in myocardial infarct patients].

The authors suggest that the males under 60 with myocardial infarction who have no chronic circulatory insufficiency in their case history should be divided into the groups of high and low risk of the development of ventricular fibrillation, thromboembolic complications and acute cardiac aneurysm. The group of risk is determined on the basis of 5 clinical characteristics: the character of myocardial infarction, the stage of arterial hypertension, evaluation of the general state, heart failure and the heart rate.

Arrhythmias, Cardiac↗
PubMed1983

[ECG manifestations in severe involvement of the coronary arteries in patients with chronic ischemic heart disease].

Correlation of electrocardiographic and coronarographic findings in patients with severe chronic coronary heart disease and massive coronary arterial lesions has demonstrated a tendency to increasing proportion of clinically normal electrocardiograms as more arteries are drawn into the pathologic process. Relationships between ECG voltage and different variants of coronary arterial damage are reviewed: the involvement of the right and part (at least one branch) of the left coronary arteries corresponds to low-voltage ECG. The association between left-ventricular aneurysm and the number of affected coronary arteries is examined.

Adult↗
PubMed1981

[Microtubule-independent cell surface stabilization in normal and transformed connective tissue cells].

Effects of colcemid on the distribution of pseudopodial activity in both normal and transformed connective tissue cells was studied by means of phase contrast microscopy and time-lapse cinematography. It was shown that normal as well as transformed fibroblasts are able to stabilize their surface independently on the presence of colcemid, however, in transformed cells this ability is more expressed. Possible mechanisms of this stabilization of cellular surface, independent on microtubules is discussed.

Animals↗
PubMed1978

[Effect of agents disrupting microtubules on the distribution of receptors on the surface of cultured cells].

Substrate-attached normal mouse fibroblasts, transformed mouse fibroblasts (L-strain) and epithelial cells (MPTR strain) were incubated with two ligands that are cross-linking different group of the surface receptors: concanavalin A and cationic ferritin. Surface-attached ligands were revealed by the indirect immunofluorescent methods. The incubation of control cells with these ligands induced a patching of corresponding surface receptors, and a clearing of these receptors from the surface zones located on the lamellar cytoplasm near the cell edges actively protruding pseudopodia. Effects of three antitubulins (colcemid, colchicine and vinblastin) on the ligand-induced redistribution of receptors were examined and compared with the previously described effects of these drugs on the distribution of active cell edges.

Animals↗