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Biomedical subjects

N S Badaev

Publications and source records attributed to N S Badaev.

18 recordsLinked to original sources
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↗
PubMed1979

[Effect of polyethyelene glycol on proliferation of cultured Chinese hamster cells].

Chinese hamster cells in suspension were treated with PEG 4000 for 20 min. It was found that cell size began to diminish already when a 5% PEG solution was used, and reached the minimal value in a 20% PEG solution. A pronounced cell death was observed when PEG concentration exceeded 20%, but cells that survived retained their proliferation potential. It is concluded that the cell death results from hypoosmotic shock when cell suspension in PEG solution is diluted.

Animals↗
PubMed1977

[Spiralization dynamics of the eu- and heterochromatin of heteromorphic homologs of the 1st pair of human chromosomes].

Peculiarities of mitotic spiralization of eu- and heterochromatic parts of heteromorphic homologous chromosomes No 1 are investigated. The homologues differ in size of their centromeric heterochromatin segments. In the spiralization range studied (the total lengths of chromosome pair equal to 8.2+25.6 mcm) the lengths of any euchromatic and heterochromatic part change approximately by 3 and 2 times, resp. It is shown that if the chromosome contraction level is not taken into consideration, neither absolute nor relative length of heterochromatic segment can be used for measuring the ratio of heterochromatin. Recommendations for quantitative determination of heterochromatin in chromosome No 1 are given.

Chromosomes, Human, 1-3↗
PubMedDate not supplied

[Formation of the regular, optical isotropic phase of low molecular weight DNA molecules modified by cis-dichlorodiammineplatinum].

It is shown that condensation of DNA molecules of low molecular mass (less than 1 X 10(6) in NaClO4-containing solution of poly(ethylene glycol) brings about formation of cholesteric liquid crystal phase; pattern of this phase is presented. It has been found by means of X-ray analysis and polarization microscopy that at certain level of modification with cis-dichlorodiammineplatinum (II) the DNA molecules instead of cholesteric structure form an ordered optically isotropic phase. The problem about the causes of the formation of such phase and about the pattern of spatial organisation of adjacent DNA molecules in it remains open.

Animals↗
PubMedDate not supplied

[2 types of temperature transitions in liquid crystals formed from poly(I).poly(C) molecules].

The small-angle X-ray scattering curves, CD spectra and textures of the liquid-crystalline phase formed from poly(I).poly(C) molecules in a water-salt solutions containing poly(ethylene glycol) at different temperatures were obtained. It was found that the heating of poly(1).poly(C) liquid-crystalline phase is accompanied by two types of transitions, the first one--a "cholesteric----"compensated" structure----cholesteric", the second--a "cholesteric----isotropic state" transition. The latter transition takes place at a temperature that corresponds to that of the separation of chains of the double-stranded poly(I).poly(C) molecule.

Circular Dichroism↗
PubMedDate not supplied

[Liquid crystals and liquid crystal dispersions of DNA-daunomycin complexes].

The X-ray and optical properties as well as the textures of liquid crystals formed of DNA molecules bound in complex with an anthracycline antibiotic daunomycin were investigated. It was shown that DNA.daunomycin complexes, depending on the extent of alteration of the DNA secondary structure by daunomycin, could yield two types of cholesterics differing in the direction of their spatial twisting as well as nematics. Liquid-crystalline dispersions of DNA.daunomycin complexes have CD spectra with "mirror" bands depending on daunomycin concentration. "Testing" of the orientation of daunomycin molecules on the DNA in liquid-crystalline particles suggested two types of binding.

Animals↗