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Biomedical subjects

A N Koterov

Publications and source records attributed to A N Koterov.

At least 19 recordsLinked to original sources
PubMed2004

Antioxidant spectrum of blood serum and its peculiarities in children.

We compared the contribution of high- and low-molecular-weight antioxidants into total antioxidant activity of blood serum in children and adults. Ten serum samples from children aged from 3 months to 12 years and 6 serum samples from adults were fractionated by chromatography and antioxidant activity and the contents of transferrin and ceruloplasmin were measured in total serum and individual chromatographic fractions. It was found that total antioxidant activity of the serum from children measured in the system of yolk lipoproteins considerably surpassed that in adults. Moreover, in adults the major part in serum antioxidant activity is played by a fist identified high-molecular-weight fraction (600 kDa) and a 67 kDa fraction containing ceruloplasmin and transferrin. Serum antioxidant activity in children was determined only by the high-molecular-weight peak not containing ceruloplasmin and transferrin, which was probably due to significantly lower serum transferrin content in children compared to adults.

Adult↗
PubMed1996

[Connection between the level of transferrin in blood plasma and the level of malondialdehyde in mouse liver].

To study possible correlation between plasma transferrin content and level of 2-thiobarbituric acid-reactive substances (malonic dialdehyde (MDA)) in the liver of mice, these parameters were assayed during brombenzol-induced lipid peroxidation and when this process was inhibited by zinc-metallothionein (zinc-MT). In 24 h after brombenzol injection (0.5-2 g/kg intraperitoneally), mice had decreased blood transferrin concentration and increased MDA level in the liver. On the contrary, in 24 h after the zinc-MT injection (1-4 mg/kg intraperitoneally), blood transferrin concentration was 2-3-fold increased and liver MDA content was 2-3-fold decreased. The effects of zinc-MT were observed even in brombenzol-injected animals. Zinc-MT injection increased total transferrin content in the blood and decreased glycosylation of this glycoprotein. Changes in blood transferrin content negatively correlates (r = -0.75) with changes in liver MDA. The data confirm that plasma transferrin can participate in regulation of tissue lipid peroxidation.

Animals↗
PubMed1993

[Lowering the acute toxicity of ethanol with a zinc-metallothionein compound].

The homogeneous drug of zinc-metallothionein (zinc-MT) which characterized according to the molecular weight and UV-absorption spectra was obtained from the liver of the rats preliminary injected with the zinc chloride. It was shown that zinc-MT (0.5-4 mg/kg of protein) injected to the mouse 10 min before the ethanol decrease the acute toxicity of the alcohol. The preliminary injection of the control mixture consisted the albumin, cysteine and zinc chloride in proportions and dose corresponding to the dose 3 mg/kg of zinc-MT did not change LD50 of ethanol. The possible mechanism of the effect is discussed. The most possible is the stabilization of the lipid peroxidation in the liver or the restoration of the thiol groups pool at the alcohol intoxication by the zinc-MT.

Animals↗
PubMed1992

[The binding of SSB-proteins with DNA in chromatin of Ehrlich ascites carcinoma cells].

Using UV-induced cross-linking between proteins and DNA, the contacts between single-stranded DNA-binding proteins (SSB proteins) and chromatin DNA have been demonstrated. Ehrlich ascites tumour DNA was labeled in vivo by inoculation of tumour-bearing mice with 3H-thymidine. The cells were irradiated with the UV light dose of 3000 J/m2, destroyed in a Triton X-100-containing hypotonic medium, and separated by centrifugation into the extrachromatin fraction and chromatin. Chromatin DNA was digested with DNAase 1, and the chromatin proteins were extracted with 2 M NaCl-polyethyleneglycol. SSB proteins from the extrachromatin fraction and chromatin were purified. Only SSB proteins from UV-irradiated cell chromatin appeared to possess a high specific radioactivity which exceeded 7.5-fold that of non-irradiated cells. There were no differences between chromatin SSB proteins in control and irradiated cells as could be evidenced from SDS electrophoresis data. It is assumed that in irradiated cells SSB proteins of DNA-digested chromatin are covalently cross-linked with DNA fragments.

Animals↗
PubMed1992

[Use of benzoyl-naphthyl-DEAE-cellulose chromatography for determining the ability of proteins from Ehrlich ascites carcinoma, binding with single-stranded DNA (SSB-proteins), to destabilize the DNA double helix].

Single-stranded DNA-binding proteins (SSB-proteins) isolated from Ehrlich ascites tumour (EAT) cells were incubated for 30 min at 5 mM NaCl with salmon sperm DNA or [3H]DNA from EAT at the SSB-protein/DNA ratio (w/w) of 0 to 4.5. After addition of sodium dodecyl sulfate up to a 0.05% concentration, the proteins were applied to columns with benzoylated naphthoylated DEAE-cellulose. Double-stranded DNA was eluted by 1 M NaCl; the DNA containing single-stranded regions was eluted by 50% dimethylformamide. There was a progressive lowering of the DNA content in the first eluate and a rise in the second eluate, as could be evidenced from the increase in the SSB-protein/DNA w/w ratio. This effect was more pronounced in the case of homologous DNA and was not coupled with the nuclease activity of SSB proteins. It was concluded that EAT SSB-proteins are "DNA-unwinding" proteins.

Animals↗
PubMed1992

Properties of single-stranded DNA-binding proteins (SSB-proteins) from chromatin and nonchromatin fractions of Ehrlich ascites tumour: phosphorylation enhances the affinity of SSB-proteins for single-stranded DNA.

To assess the possible functional role of single-strand DNA-binding (SSB) proteins in eucaryotic cell, a comparative study was made of SSB-proteins isolated from chromatin and the nonchromatin fractions of Ehrlich ascites tumour (EAT) cells. No appreciable differences between the two groups could be found either in SDS-gel electrophoretic patterns or in the ssDNA-binding capacity and stimulation of DNA replication in permeable EAT cells. However, the chromatin SSB-proteins incorporated 1.4-times more labelled phosphate in vivo; phosphate assays in the isolated chromatin and nonchromatin SSB-proteins yielded ca. 3 and 2 moles Pi/mole protein, respectively. Both preparations could be further phosphorylated in vitro with Ca-phospholipid-dependent protein kinase and the catalytic subunit of cAMP-dependent protein kinase, but the non-chromatin proteins were phosphorylated to a greater degree. In parallel with phosphorylation, the SSB-proteins displayed stronger binding to ssDNA cellulose. Phosphorylation may thus be a means of regulating the functions of SSB-proteins, in particular their interaction with chromatin.

Animals↗
PubMed1992

Relationship of single-stranded DNA-binding proteins of Ehrlich ascites tumour to cell growth phase and DNA replications.

The possible involvement of SSB-proteins in DNA replication in Ehrlich ascites tumour (EAT) has been investigated. A direct relation (the computer-generated correlation coefficient was 0.9) between the SSB-proteins content in chromatin and intensity of the replicative synthesis of DNA in various preparation of EAT in vivo and in vitro is observed. Addition of exogenous SSB-proteins to the permeable EAT cells has been found to increase the replicative synthesis. Although eukaryotic SSB-proteins are not complete analogs of the prokaryotic SSB-proteins, they evidently participate in DNA replication in eukaryotic cells and possibly are intracellular regulators of proliferation.

Animals↗
PubMed1991

[Phosphorylation and other properties of proteins binding single-stranded DNA (SSB-proteins) from chromatin and extrachromatin fractions of Ehrlich ascites carcinoma].

A comparative study of single-stranded DNA-binding proteins (SSB-proteins) isolated from chromatin and the extrachromatin fraction of Ehrlich ascites tumour cells was carried out. No differences were found either in SDS-gel electrophoretic mobility or in the single-stranded DNA-binding capacity and stimulation of the replicative synthesis of DNA. However, chromatin SSB-proteins contained 1.4-1.5 times more phosphate than extrachromatin proteins. Both preparations could be phosphorylated in vitro by protein kinase C and cAMP-dependent protein kinase, but the chromatin proteins were phosphorylated in a lesser degree. In parallel with phosphorylation the SSB-proteins displayed a higher binding affinity for ssDNA-cellulose. Phosphorylation can thus be regarded as a means of regulation of the SSB-protein function, in particular, their interaction with chromatin DNA.

Animals↗
PubMed1990

[The role of protein binding with single-stranded DNA (SSB-protein) in DNA replication in Ehrlich ascites carcinoma cells].

Possible involvement of the single-strand DNA-binding protein (SSB-protein) in DNA replication in Ehrlich ascite tumour (EAT) cells was studied. There was a direct correlation between the content of SSB-protein in chromatin and the intensity of replicative synthesis of DNA in various preparations of EAT in vitro and in vivo (the computed value of the correlation coefficient was equal to 0.9). It was shown that the addition of exogenous SSB-protein to permeable EAT cells increased the replicative synthesis. It was concluded that although eukaryotic SSB-proteins are not complete analogs of prokaryotic ones, they may participate in DNA replication in eukaryotic cells and, possibly, are intracellular regulators of proliferation.

Animals↗
PubMed1989

[Effect of agents for the chemical prevention of radiation sickness on the cyclic nucleotide content in the bone marrow of mice].

The effect of different chemical compounds on the cAMP/cGMP ratio in the bone marrow of mice and radioresistance of animals has been studied. It has been shown that all compounds possessing radioprotective properties give rise to the cAMP/cGMP ratio in the bone marrow of mice. No changes in cAMP and cGMP level were noted after the administration of nonradioprotective substances. The maximal radioprotective effect coincide in time with the largest increase of the cAMP/cGMP ratio. The injection of radioprotectors at different doses demonstrate clearly that only at radioprotective doses the increase in the cAMP/cGMP ratio takes place. The administration of some substances 2, 15 and 60 min after the irradiation of mice shows that the radioprotective effect, though modest, was evident only in one case of elevated cAMP/cGMP ratio (the injection of 2-Mercaptoethylamine 2 min after the irradiation). Evident radioprotective effect occurs at the cAMP/cGMP ratio of about 170-200%; the ratio of about 130-140% corresponds to small radioprotection.

Animals↗
PubMed1988

[Isolation and characteristics of single-stranded DNA-binding protein (SSB-protein) from Ehrlich ascites carcinoma cells].

Single-stranded DNA-binding protein (SSB-protein) has been purified and characterized from Ehrlich ascite tumour (EAT) cells. The purification procedure was performed in analytical and preparative variants. It was shown that in the analytical variant of the purification procedure can be used to determine protein concentration in the cell. The molecular mass of the SSB-protein as determined by SDS polyacrylamide gel electrophoresis is 36 and 43 kD; that determined by gel filtration is 27, 28, 43 and 44 kD; pI is 7.4. The use of nitrocellulose filters showed that the SSB-protein binds preferentially to ss-DNA. The protein contains no admixtures of DNA-polymerases, endo- or exonucleases, DNA-dependent ATPase, lactate dehydrogenase and HMG-proteins. The SSB-protein stimulates 1.5-2-fold the activity of DNA-polymerase alpha from EAT, it does not activate DNA-polymerase beta from EAT and strongly inhibits the activity of exonuclease (snake venom phosphodiesterase). The specificity of the term "SSB-protein" which makes it different from other non-histone proteins of chromatin is discussed.

Animals↗