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Biomedical subjects

A G Bulychev

Publications and source records attributed to A G Bulychev.

At least 37 records · Page 2Linked to original sources
PubMed1988

[Effect of the segregation and accumulation of chloroquine and daunorubicin by L cells (LSM subline) on the activity of lysosomal hydrolases].

Kinetics of chloroquine and daunorubicin (DNR) uptake by cultured L cells (subline LSM) has been studied. With their constant concentrations in the medium the uptake of both chloroquine and DNR was characterized as a two phase process. Within 1.5-2 hours, these cells accumulated as much as 90 per cent of the total chloroquine and DNR amounts taken up during the whole incubation period. The segregation and accumulation of these substances took place in lysosomes. Chloroquine and DNR concentrations within lysosomes exceed those in the medium by 1100 and 5000 times, respectively. The chloroquine and DNR accumulation in lysosomes inhibited activities of some lysosomal hydrolases tested: cathepsins B and D, N-acetyl-beta, D-glucosaminidase and acid phosphatase. Unlike, the activity of acid lipase was not affected by chloroquine, and was sufficiently stimulated (by 55%) by DNR. The mechanism of inhibition of lysosomal enzymes by chloroquine and DNR is not yet known, although some suggestions are made. Possible consequences of lysosomal activity inhibition for cell metabolism are discussed in addition to a possible role of lysosomotropic agents as regulators of lysosomal functional activity.

Animals↗
PubMed1988

[Electron microscopic and biochemical research on the vacuoles formed in the erythrocytes of frogs as affected by neutral red and novocaine].

No lysosomes were found in the frog intact erythrocytes with electron microscope. Under the influence of neutral red (NR-8.7.10(-5) M) and novocaine (N-4.6.10(-3) M) segregation zones (vacuoles) including these substances are formed. Using electron microscopy and morphometry the action of NR and N for 5 minutes up to 48 hours was found to provoke the formation of four types of vacuoles differing in their morphology: with electron-transparent content, with amorphous inclusions and membrane whorls. The dynamics of vacuole formation, of their changes and amount were followed depending on the time of exposition of these substances. Biochemical investigation of both NR and N isolated vacuoles showed in these some activities of lysosomal marker enzymes--acid phosphatase and N-acetyl-beta,D-glucosaminidase. Ultrastructural investigation of acid phosphatase localization in the isolated vacuoles revealed the histochemical reaction product mainly in electron-translucent vacuoles (primary lysosomes) and partly in electron dense ones (secondary lysosomes). On the ground of the above studies a conclusion is made that in frog erythrocytes treated with NR and N lysosome formation is induced to be followed by the induced autophagocytosis and heterophagocytosis. Some possible ways of the vacuolar system formation in frog erythrocytes and the origin of lysosomal hydrolases are discussed.

Animals↗
PubMed1987

[Characteristics of the granules formed in nucleated erythrocytes as affected by cardiotrast].

Numerous granules are formed in frog erythrocytes under the influence of cardiotrast (C) (diethanolamine-3,5-diiodo-4-pyridone-1-acetic acid). However, as revealed by cytospectrophotometric investigation and X-ray microanalysis, no C was accumulated in these granules. It is known that C can dissociate into diethanolamine and 3,5-diiodo-4-pyridone-1-acetic acid. It was assumed that under the influence of C granule formation may occur at the expense of an uncharged diethanolamine form penetrating into lysosome-like structures to be accumulated by protonation process. Diethanolamine was found to provoke granule formation in frog erythrocytes. It is impossible to reveal substance in granules because it is colourless and has no ultraviolet absorbtion band. Under the influence of some inhibitors of energy metabolism on granule formation and the granules formed, their inhibitory effect is exerted on the process of granule formation. In granules isolated by differential centrifugation activity of some marker lysosomal enzymes was found which enabled us to attribute these granules to lysosome-like structures.

Animals↗
PubMed1986

[Segregation function of the cell and its molecular mechanisms].

Current literature on the cell segregation function is reviewed. The modern data on the role of coated pits, coated vesicles and endosomes in receptor-mediated and fluid endocytosis are regarded. Mechanisms of segregation both of inorganic and organic substances in lysosomes are considered. A special attention is paid to the selective accumulation in lysosomes of substances penetrating through plasma membrane. Some modern considerations concerning the role of the ATP-dependent proton pump in maintaining low intralysosomal pH and accumulation of weak bases in lysosomes by means of protonation are given. A great attention is paid to the effect of accumulated foreign substances in lysosomes on lysosomal apparatus functions and some metabolic disorders as consequences of it. The importance of the cell segregation functions and of lysosomotropic compounds for cytopharmacology and cytopathology is emphasized.

Animals↗
PubMed1986

[Effect of the segregation of neutral red, acridine orange and ammonium chloride by L cells (subline LSM) on lysosomal hydrolase activity].

Kinetics of Neutral red (NR) and Acridine orange (AO) uptake by cultured L cells (subline LSM) has been studied. It was found that the uptake of both NR and AO, with their constant concentrations in the medium was characterized as a two-phase process. During 2 hours, these cells concentrated as much as 90% of the total amount of NR and AO taken up during the whole incubation period. The segregation and accumulation of NR, AO as well as NH4Cl took place in lysosomes. NR and AO concentrations within the cells exceed by 600 and 400 times, respectively, those in the medium. NR, AO and NH4+ accumulation in cells resulted in inhibition of the activity of the following lysosomal hydrolases: cathepsins B and D, acid lipase, N-acetyl-beta,D-glucosaminidase, beta-galactosidase, acid phosphatase and galactosyltransferase, the latter being a marker of Golgi apparatus. The effect of lysosomal enzyme activity inhibition on the cell economy, and a possible role of lysosomotropic agents as regulators of the lysosomal apparatus functional activity are discussed.

Acridine Orange↗
PubMed1985

[ATPase activity of the novocaine segregation zones isolated from the erythrocytes of the common frog].

Novocaine segregation zones in frog's erythrocytes, isolated by differential centrifugation, were shown to be ATPase active. The enzyme displays half of its maximum activity at 0.18 Mm ATP concentration to be inhibited by high concentrations of ATP. ATPase is activated by both Mg2+ and Ca2+ (in a lesser degree), with the maximum activity being at pH 7.5. A 5 minutes heating without the substrate results in decreasing the enzyme activity at 30 degrees, and in the total inhibition at 50 degrees C. Along with ATP, the enzyme can hydrolyse GTP and, in a lesser degree, ADP and sodium pyrophosphate. The ATPase activity is not effected with oligomycin (0.5-1.5 mkg/ml) or ouabaine (0.1 mM). Oligomycin in concentration 5 micrograms/ml induced non-specific inhibition of ATPase. Uncouplers, like 2,4-dinitrophenol and carbonyl cyanid p-trifluorometoxyphenylhydrazone, stimulate the enzyme activity. The lack in the ATP-ase sensitivity to oligomycin (specific inhibitor of mitochondrial F1-ATPase) and ouabaine (specific inhibitor of Na+, K+-ATPase) may suggest that the ATPase activity of novocaine segregation zones in frog's erythrocytes is not associated with a random contamination with mitochondria or cytoplasmic membranes. The ATPase under study has much in common with the lysosomal +H-ATPase. The results obtained support a hypothesis that +H-ATPase may function as a course of protones for maintaining acidic medium in segregation zones and promote accumulation of weak bases by means of their protonation.

Adenosine Triphosphatases↗
PubMed1985

[Effect of metabolic inhibitors on formed novocaine and neutral red segregation zones in frog erythrocytes].

Effects of some metabolic inhibitors, as well as of biologically active compounds (diakarb, ethidium bromide and a phenanthridine alkaloid sanguinarine) on the formed novocaine and neutral red segregation zones were studied. The volume of granules diminished under the influence of a glycolytic inhibitor iodoacetate, uncouplers of oxidative phosphorylation (2,4-dinitrophenol and carbonyl cyanide trifluoromethoxyphenylhydrozone), and respiratory inhibitors (antimycin A and rotenone), as well as under the influence of cycloheximide - an inhibitor of protein synthesis. Diakarb, ethidium bromide or sanguinarine also provoked a regression of the segregation zones. It has been found that all these compounds are inhibitors of ATPase activity of the isolated segregation zones. A possible mechanism of volume decreasing in segregation zones under the influence of both the metabolic inhibitors and diakarb, ethidium bromide and sanguinarine is discussed.

Adenosine Triphosphatases↗
PubMed1984

[Cytophotometric study of the granules formed in frog erythrocytes incubated in solutions of acridine orange, chloroquine and daunorubicin].

Granules arising in the cytoplasm of Rana temporaria erythrocytes incubated in either solution containing acridine orange, chloroquine or antibiotic daunorubicine were studied cytophotometrically. The stuff concentrations in the granules were estimated under various conditions of incubation. The stuff concentrations in the granules appeared to be 1000-fold higher than in the incubation solutions. The average concentration in the granules did not depend on either the initial concentration of the stuff solution or the incubation time. The stuff concentration in the granules decreases with the increase of the granule size. Mechanisms of cation-acid segregation and accumulation by living cell are discussed.

Acridine Orange↗
PubMed1983

[Effect of inhibitors of energy metabolism and protein synthesis on the process of neutral red segregation in frog erythrocytes].

Effects of inhibitors of energy metabolism and protein synthesis on Neutral red segregation in frog erythrocytes were studied. Inhibitors of both glycolysis and respiration significantly reduced formation of segregation zones. This influence was most striking with antimycin A, rotenone and cyanide. This indicates that intact respiratory pathways may play an important part in the process of Neutral red segregation. Such uncouplers as FCCP (carbonyl cyanide p-trifluoromethoxyphenylhydrazone) and 2,4-dinitrophenol (DNP) as well as inhibitors of oxidative phosphorylation (arsenate and azide) are also very effective in inhibiting the Neutral red segregation at low concentrations. The effects of these uncouplers and of olygomycin suggest an important role of ATP as an energy source for the segregation process. An inhibitor of protein synthesis, such as cycloheximide, produces some reduction in segregation zones formation. Trapping of Neutral red by protonation could readily explain the high level of this dye accumulation in nucleated erythrocytes. The fact that low concentrations of FCCP and DNP inhibit the process of segregation brings a supporting evidence for the possibility of the ATP-driven proton pump involved in Neutral red segregation.

Animals↗
PubMed1983

[Changes in lysosomal enzyme activity in the mitotic cycle of L cells].

Activities of lysosomal enzymes (acid phosphatase, N-acetyl-beta-D-glucosaminidase, acid lipase and cathepsin D) have been examined in a synchronized culture of mouse L-fibroblasts. Cell synchronization was achieved by the double thymidine block with a subsequent mitotic selection after colcemid treatment. Specific activities of the enzymes studied were found to be higher in S-G2 that in G1. There is a linear increase (approximate doubling) in enzyme activities per cell from G1 to M. Activity of galactosyltransferase, a marker of the Golgi apparatus, declined in mitotic cells in comparison with the interphase cells. Ultrastructural examination of L-cells revealed a reduction of the intracellular membrane system including the Golgi apparatus during mitosis. Changes in the Golgi apparatus activity have been considered as a possible regulatory point of lysosome formation. The data presented are compared with the results of morphological studies of lysosomal system in L-cells.

Animals↗
PubMed1982

[Lysosome changes in exponentially growing, synchronized and differentiating L-cell cultures].

Using supravital fluorescent staining of lysosomes with Euchrysine 3R, the morphology of these organelles was studied in L cells examined from cultures being at different growth phases in the course of cell cycle and after adipocyte conversion of L cells due to the 60% bovine serum administration. As cells were passing from the lag-phase to the stationary phase of culture growth, the number of lysosomes was seen to increase. The appearance of large lysosomes is characteristic of cells in confluent and senescent cultures. During G1-period, lysosomes are often confined to the perinuclear area of L-cells, to be extended later during S and G2-periods. In dividing cells, these are commonly seen scattered throughout the cell periphery, around the mitotic spindle. In cells undergoing differentiation, within 4-7 days the seeding in the medium supplemented with 60% bovine serum, the number of lysosomes became augmented to be gradually reduced during the next 10-15 days, concomittantly with the accumulation of lipid drops in the cell cytoplasm. The activity of the Golgi complex and the intensity of autophagy are discussed as possible regulation points of lysosome formation during the cell growth.

Acridine Orange↗
PubMed1981

[Increase in the cAMP content of mouse brain cells in ischemia and inhibition of this effect by certain biologically active compounds].

Anoxia (during 2 minutes after decapitation) produced a significant elevation of cAMP contents (up to 410%) in mouse brain cells. This effect was abolished by an intraperitoneal injection of alloxan (A), morphine (M), and ethanol (E) 30 minutes before decapitation, and after a 2 minutes diethyl ether (DE) inhalation. It was found that anoxia produced some decrease in phosphodiesterase (FDE) activity. A preliminary injection of A and E produced an activation of FDE; M and DE did not change FDE significantly. Mechanisms of action of all the four agents on the cAMP content under anoxia are different. A and E produced a rapid cAMP hydrolysis on stimulating the activity of FDE, M and DE inhibited apparently adenylate cyclase. The activation of adenylate cyclase due to anoxia is considered as one of the initial steps in the cell injury extention.

Alloxan↗
PubMed1978

[Effect of cyclic nucleotides and histone fractions on mitochondrial respiratory and phosphorylating activity].

CAMP in the wide range of concentrations (3.10(-7)--10(-3) M), cGMP (10(-6)--10(-5) M) and dibutyril-cAMP (3.10(-6) M) produced no effect on oxidative phosphorylation of rat liver mitochondria. Among histone fractions (H1, H3 and H4) tested, the arginine-rich fraction H3 (18 microgram/mg of mitochondrial protein) produced a strong uncoupling effect. It is supposed that the effect of cAMP on oxidative phosphorylation of mitochondria may be carried out indirectly through activation of protein kinase, phosphorylation of histones, and their release into the cytoplasm.

Animals↗