Search PubMed⌕ Search

Biomedical subjects

Iu M Evdokimov

Publications and source records attributed to Iu M Evdokimov.

At least 19 recordsLinked to original sources
PubMed1990

[Study of the properties of condensed forms of the complexes of linear and supercoiled DNA with mitoxantrone and bisantrene].

The effect of anthrachinone and anthracene derivatives on linear and circular superstranded molecules of DNA in conditions of their condensation was studied. It was shown that the compounds formed strong intercalation complexes with the molecules of the linear and circular superstranded DNA when the DNA molecules were in the condensed condition. The optical properties of the disperse liquid crystal phases formed of the complexes of the investigated compounds with the molecules of linear double-chain DNA differed. Moreover, the optical properties of the condensed phases formed of the complexes of the compounds with the molecules of linear and circular superstranded DNA also differed. The causes of the differences are discussed.

Anthracenes↗
PubMed1988

[DNA liquid crystals as a possible system of testing the interactions between DNA and biologically active compounds of platinum (II) and various antibiotics].

DNA liquid crystals forming in water-salt solutions containing polyethylene glycol were used as a system for testing consequences of reactions of antitumor compounds belonging to two different groups with molecules of nucleic acids. It was found that with due account of the level of DNA molecule filling with daunorubicin it was possible to form two cholester phases characterized by the textures of "finger prints" and CD spectra with intensive bands of unlike signs, as well as the nematic phase characterized by the texture of the "black twisted fiber" system and the absence of the CD spectrum intensive band. Modification of the DNA molecules resulting from the reaction with cysdichlorodiamine platinum (II) led to formation of a new liquid crystalline phase with properties differing from those of the liquid crystalline phases of the cholester or nematic type.

Antibiotics, Antineoplastic↗
PubMed1984

[Optical properties of DNA complexes with antitumor compounds of bivalent platinum].

The optical properties of the DNA complexes with the compounds of bivalent platinum were studied. The compounds differed by the nature of the anionic and neutral ligands and their spatial arrangement about the platinum atom. It was shown that the same as cis-[Pt (NH3)2Cl2] the platinum compounds with the biological activity, i.e. [Pt (en) Cl2], cis-[PtNH3 (Bz) Cl2] and cis-[Pt (NH3)2NO2Cl] induced at low values of r (a ratio of the number of the platinum moles added to the number of the DNA nucleotide moles in the solution) an increase in the amplitude of the positive band in the spectrum of the circular dichroism (CD) of the linear DNA and a marked decrease in the amplitude of the negative band in the spectrum of the CD of the liquid crystalline microphase of DNA formed in the presence of polyethyleneglycol. By the character of the action on the CD spectrum of the linear and condensed DNA [Pt (tetrameen)Cl2] which had no selective antimitotic effect might be referred to the above platinum compounds. Trans-[Pt (NH3)2NO2Cl], [PtNH3PyCl2], cis-[Pt (NH3)2(NO2)2] and [Pt (NH3)3Cl]Cl having no biological activity either induced only a decrease in the amplitude of the positive band in the CD spectrum of the linear DNA or had no effect on the CD spectrum. The effect of these compounds on the CD spectrum of the liquid crystalline microphase of DNA was slightly pronounced or not observed.

Animals↗
PubMed1983

[Characteristics of the circular dichroism spectra of liquid crystals formed from DNA complexes with antibiotics].

Compact particles were formed from low molecular DNA in water-salt solutions (0.3 M NaCl, pH 6.7) containing polyethylene glycol. The DNA molecules in these particles were in the mesophase (liquid crystalline) state characterized by an intensive negative bond in the circular dichroism (CD) spectrum. Binding of DNA to anthracycline antibiotics (daunomycin, aclacynomycin), oligopeptide antibiotics (distamycin, nethropcin) and ethidium bromide with subsequent formation of liquid crystals from such complexes was accompanied by appearance of CD spectra with characteristic features of the respective antibiotic groups. The characteristic features of the CD spectra allowed distinguishing various antibiotics.

Anti-Bacterial Agents↗
PubMed1983

[Effect of biologically active compounds of divalent platinum on the properties of the liquid crystal "microphase" of DNA].

The optical properties of the "microphases" modeling the state of the DNA molecule in the cell and formed of both the low molecular DNA and the DNA complexes with cis- and trans-isomers of dichlorodiamine platininum (II) were studied. It was shown that the intensive band characteristic of the circular dichroism spectrum of the initial DNA "microphase" was decreasing with binding of DNA to cis-Pt (II) or trans-Pt (II). The effect of cis-Pt (II) on the "microphase" optical properties was more significant than that of trans-Pt (II). The effect correlated with the biological activity of the cis- and trans-compounds of platinum. Possible causes of the decrease in the optical activity of the DNA "microphase" are discussed.

Animals↗
PubMed1982

[Changes in the spatial organization of DNA molecules induced by anthracycline antibiotics].

The optical properties of the mesophases modeling the condensed state of cell DNA molecules formed from the complexes of 7-anthracycline antibiotics with double-stranded low-molecular DNA and polynucleotides were studied. The parameters of the antibiotic binding to the DNA during formation of the mesophases (0.3 M NaCl, 150 mg/ml of polyethylene glycol) are presented. It was found that the CD mesophase spectrum formed from the complex of DNA-antibiotic was characterized by the presence of intensive negative bands in the region of absorption of the chromophores of both DNA and antibiotic. This is indicative of regular spiral organization of the DNA mesophase. Binding of the antibiotic to DNA and polynucleotides was accompanied by changing of the band negative mark (at definite levels of the DNA molecule filling with the antibiotic) in the CD mesophase spectrum to the positive one. It was shown that with respect to the mesophases formed from the complexes of DNA with iremycin and aclacinomycin A no changing in the band marks was observed. Consequently, antibiotics may be conditionally divided into 2 groups. The antibiotics of the first group induce changes in the spin direction of the DNA mesophase, while the antibiotics of the second group had no such effect. It was demonstrated that antibiotic binding with the AT-rich sequences induce more pronounced changes in the mesophase properties than that with the GC-rich sequences. Possible causes of the mark changing in the spin of the DNA mesophase during the DNA binding with antharcyclines are discussed. Biological significance of the phenomenon is still unclear.

Aclarubicin↗