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Biomedical subjects

V Ia Brodskiĭ

Publications and source records attributed to V Ia Brodskiĭ.

At least 19 recordsLinked to original sources
PubMed1994

[Ribosomal RNA synthesis and the count and type of nucleoli in rat hepatocytes].

Changes in the activity and number of nucleoli has been studied in hepatocytes of the same rat before and after partial hepatectomy. In the latter case, the rate of ribosomal RNA (rRNA) synthesis was increased by a factor of 1.7, on the average. The synthesis was evaluated by incorporation of adenosine triphosphate in situ after alpha-amanitine treatment of squashed cells. In 2c, 4c and 8c nuclei, the number of labeled nucleoli was less than in nucleolonemic nucleoli stained with silver nitrate. These values were drawn together during stimulation of rRNA synthesis but the difference was often preserved especially for highly ploid nuclei. The lack of activity in part of nucleolonemic nucleoli was assumed. After stimulation of RNA synthesis, the number of nucleolonemic and satellite nucleoli decreased, while the size of preserved nucleoli was enlarged. The number of nucleoli did not correspond to the nuclear ploidy; their total size was proportional to the gene dosage. The mean level of rRNA synthesis was similar in nuclei of the same ploidy with two, three and four nucleoli. A great variability was detected in the rate of rRNA synthesis as well as in the number of nucleoloneme and satellite nucleoli in hepatocytes of the control and experimental rats. Some difference was observed in the label degree for nucleoli of the same nucleus.

Animals↗
PubMed1992

[Myocyte polyploidy in human cardiac pathology].

With general atherosclerosis, the ploidy of left ventricle myocytes in the hearts of patients that underwent infarction corresponds to the norm variation irrespective of the ventricle and heart weights. At heart diseases the myocyte nucleus ploidy is often much higher than the norm variability both in hypertrophied ventricles and in those with normal weight. An additional polyploidization is suggested that may occur at some natural ontogenetic periods of human development (in the childhood) during heart diseases both innate or spontaneously appearing at the particular time. Unlike, the myocardial hypertrophy in adults does not stimulate myocyte polyploidy.

Cardiomegaly↗
PubMed1992

[Ploidies of cardiomyocytes in human myocardial hypertrophy].

DNA cytophotometry has been performed in ventricular cardiomyocytes of hypertrophic human hearts. In the cases of hypertrophy in adults (generalized atherosclerosis, postinfarct scars), polyploidy expression did not exceed the limits of normal variability developed during childhood. In the cases of hypertrophy caused by congenital heart defects, high polyploidy has been revealed (the mean level 20c and more, where c is haploid DNA content), which considerably exceeded the upper limit of normal variability (approximately 10c). Our hypothesis has confirmed that heart hypertrophy in adults proceeds in conditions of stable genome rather than due to redundant polyploidization of the ventricular myocytes. The same idea assumes enhanced polyploidization of the myocytes in childhood in humans with congenital heart diseases.

Adult↗
PubMed1991

[The possible cytophotometry of nucleolar proteins. The prospects for research on the status of the nucleolus apparatus].

Possibility of cytophotometry application was established for the acid nucleolar proteins reacting with silver nitrate. The increase in transcription in the Purkinje neurons results in the expansion of the Ag-proteins areas, whereas their amount may be not increased. The amount and area of the Ag-proteins double in hepatocytes through polyploidization, but the number of nucleoli does not correspond to the gene dosage. This lack of correspondence was also revealed in micronucleoli. The number of nucleoli is not similar in the nuclei of some binuclear hepatocytes, and this disproportionality increases through polyploidization.

Animals↗
PubMed1991

[Protein mass in human cardiomyocytes does not correspond to gene content].

Lack of proportionality between DNA and protein content has been revealed in the human cardiac myocytes. The proportion 2:4:8:16 was observed in DNA of di-, tetra-, octa- and hexadeca myocytes while the protein content of the same cells was 2:3.5:5.2:7.2 in the inner layer, 2:3.5:6.5:8.9 in the central layer and 2:3.1:5.6:9.1 in the outer layer of the normal left ventricle. The protein content of myocytes of the same ploidy was higher in the inner layer than in other ones.

DNA↗
PubMed1990

[Circadian rhythm of tRNA aminoacylation in hepatocyte culture].

In the monolayer of rat hepatocytes in vitro, the circadian rhythms were revealed of 3H-leucine incorporation in proteins and in aminoacyl-tRNA(Leu) fraction. The oscillations were mainly synphasic, though coordination between aminoacylation and protein synthesis was not stable in the coarse of time. In cell free system with the excess of ATP and aa-tRNA, the rhythm of 3H-leucine incorporation was also clear. This means, that oscillatory kinetics of the protein synthesis rate is not caused by oscillation of ATP which has been revealed earlier in the hepatocyte monolayer.

Acylation↗
PubMed1989

[The ploidy variability of human cardiomyocytes].

Unlike literature on ploidy of the human myocytes, DNA content and the number of nuclei have been revealed in the same cells. Besides, the cell ploidy were studied separately in the external, central and inner regions in the left ventricule. Considerable binucleation was revealed in normal and hypertrophic ventricles where 4c X2 was the modal cell class and there were 2c X 2, 8c X 2 and single 16c X 2 cells. Two alternative assumptions have been put forward concerning the genome differences: 1) myocytes enter in mitotic cycle under pathologic conditions or 2) the difference causes in genuine variability of the ploidy classes in normal hearts.

Adolescent↗
PubMed1985

[Change n the ploidy classes of left ventricular myocytes in rats after ligation of the left coronary artery].

Heterogeneous response of cardiomyocytes in left atria of rats to ligation of the left coronary artery was observed. Ploidy may greatly increase reaching 32 c per cell. More than 90% of myocytes are normally mononuclear diploid cells, while after the ligation the number of such cells diminishes to 10%. The majority of cells become polyploid: above 50% of cells are 2 X 2 c ploid, about 30% of cells are 4 X 2 c ploid and a great number of cells are highly ploid.

Animals↗
PubMed1984

[Changes in the protein mass and ploidy level of the myocytes in the mouse heart].

Neonatal mice were grown until 3 weeks of age at a rate of four or sixteen per litter (groups I and II, respectively). The group I animals were characterized by accelerated growth. At day 21 of postnatal development their body and heart weights were three times greater than those of the group II animals. The mean protein content in cardiomyocytes of the group I animals increased faster, correlating with the increase of the heart weight. The fast-growing mice showed an increase in the number of polyploid cardiomyocytes (polynucleate cells mainly), amounting to 15-16% as compared with 2-4% seen in normal and slow-growing animals.

Animals↗
PubMed1984

[Possible role of ornithine decarboxylase in controlling the hourly rhythm of protein synthesis].

A study was made of the effect of non-competitive inhibitors of ornithine decarboxylase (1,3-diaminopropane and cadaverine) on the circahoralian rhythm of protein synthesis in liver sections incubated in vitro. Addition of diamines to the culture resulted in a decrease in the amplitude of protein synthesis fluctuations and in some cases in an almost complete rhythm wearing. It is suggested that diamines affect the rhythm of protein synthesis by inhibiting the key enzyme of polyamines--ornithine decarboxylase.

Animals↗