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Biomedical subjects

A A Gusev

Publications and source records attributed to A A Gusev.

At least 19 recordsLinked to original sources
PubMed2004

Trapped antiprotons produced by cosmic rays in the Earth's magnetosphere.

The existence of significant fluxes of antiparticles in the Earth magnetosphere has been predicted on theoretical considerations in this article. These antiparticles (positrons or antiprotons) at several hundred kilometers of altitudes, we believe are not of direct extraterrestrial origin, but are the natural products of nuclear reactions of the high energy primary cosmic rays (CR) and trapped protons (TP) confined in the terrestrial radiation belt, with the constituents of terrestrial atmosphere. Extraterrestrial positrons and antiprotons born in nuclear reactions of the same CR particles passing through only 5-7 g/cm2 of interstellar matter, exhibit lower fluxes compared to the antiprotons born at hundreds of g/cm2 in the atmosphere, which when confined in the magnetic field of the Earth (in any other planet), get accumulated. We present the results of the computations of the antiproton fluxes at 10 MeV to several GeV energies due to CR particle interactions with the matter in the interstellar space, and also with the residual atmosphere at altitudes of approximately 1000 km over the Earth's surface. The estimates show that the magnetospheric antiproton fluxes are greater by two orders of magnitude compared to the extraterrestrial fluxes measured at energies <1-2 GeV.

Atmosphere↗
PubMed2002

[Microvzor-2: a system for automated dry blood smear analysis].

Upgraded system Microvzor-2 for investigation of blood morphology in space flight is composed of soft- and hardware for dry smear image analysis. Ground-based testing showed that it could be utilized to investigate a broad spectrum of blood parameters in space flight, including erythrocytes, hemoglobin content in erythrocytes, volumetric erythrocyte distribution, diagnostics of anisocytosis, and poikilocytosis, leukocytes and leukocyte count. Analyzed are smears prepared from a fixed volume of finger blood. The process consists of smear scanning, input of the vision field images in the spacecraft computer and ensuing automated identification and counting. Information is stored in a dedicated database. Results of analysis are displayed as forms and cell galleries.

Adaptation, Physiological↗
PubMed2000

[Sequence analysis of hexon gene from adenovirus KR95 inducing hydropericardium syndrome in chickens].

The nucleotide sequence of a part of the HindIII-D fragment (3300 b.p.) of adenovirus KR95 DNA has been determined. Analysis of the nucleotide sequence disclosed a continuous ORF for hexon gene (2814 b.p.) coding the 937 residue protein, part of ORF for the C-terminal region of pVI polypeptide, including 114 residues and the beginning of ORF coding 25 N-terminal residues for viral endoproteinase. Comparison of predicted KR95 hexon sequence and 8 mammalian and avian adenovirus hexon sequences revealed the highest homology between KR95 strain and avian adenoviruses FAV10 and FAV1 (91.1 and 80.1%, respectively). The results were used for creating a test system on the basis of the polymerase chain reaction. The system was used in analysis of fowl samples obtained from 12 poultry farms in Russia. The sequences of hexon gene amplified fragments in the isolated strains and similar fragments of other mammalian and avian adenoviruses have been compared.

Adenoviridae↗
PubMed2000

[Primary structure of the F-gene from Rinderpest virus strain K].

Synthesis, cDNA cloning, and nucleotide sequencing of F gene of rinderpest virus strain K was carried out. Analysis of nucleotide sequence showed the only open reading frame coding for protein from 546 a.o. with mol. weight 58.6 kDa. The mean percentage of identical nucleotide residues between F genes of strains K, Kabete O, and L is 76.4% for 5'-untranslated region and 90.5% for translated region, the share of similar amino acid residues in the respective proteins is 92.9%. The structure of restriction site of F0 precursor protein in rinderpest strains with different virulence is similar. Protein F of rinderpest virus strain K has 3 potential glycosylation sites and 13 cystein residues in positions identical to those of F protein of rinderpest strains Kabete O and L.

5' Untranslated Regions↗
PubMed1999

[Strain differentiation of the Newcastle disease virus by reverse transcriptase-polymerase chain reaction and sequencing population exchange].

A system for detection and strain differentiation of Newcastle disease virus (NDV) by reverse transcription of polymerase chain reaction (RT-PCR) (isolation of RNA, choice of primers for nested PCR, and purification of PCR products) and sequencing is developed and optimized. A nucleotide sequence of gene F site, coding for the F2/F1 cleavage site of F0 fusion protein and including several hypervariable regions, is determined for 10 Russian strains and vaccine strains. The data indicate a replacement of NDV populations in Russia and a rapid evolution of the virus. The origin of pathogenic NDV strains which have been circulating up to the present time is still unknown.

Base Sequence↗
PubMed1999

[The nucleotide sequences of the HN gene and F gene fragment of Newcastle disease virus strains BOR74 and BOR82].

The complete nucleotide sequence of HN gene, the region of F gene, and intergene regions (M-F, F-HN, and HN-L) of the BOR74 and BOR82 strains of Newcastle disease virus have been determined. Based on the nucleotide and amino acid sequences, the speeds of the nucleic and amino acid changes were calculated (approximately 10(-3) nucleotides or amino acids/year). The BOR strains were grouped phylogenetically with the asymptomatic strains. These strains and the BOR strains have the same motif of the cleavage site (112GKQGR116-L117), but the HN protein of BOR strains has the 572 amino acids which differ the BOR strains from all other strains (571, 577, and 616 amino acids).

Base Sequence↗
PubMed1998

Sources of inner radiation zone energetic helium ions: cross-field transport versus in-situ nuclear reactions.

Radial transport theory for inner radiation zone MeV He ions has been extended by combining radial diffusive transport, losses due to Coulomb friction and charge exchange reaction with local generation of 3He and 4He ions due to nuclear reactions taking place on the inner edge of the inner radiation zone. From interactions between high energy trapped protons and upper atmospheric constituents we have included a nuclear reaction yield helium flux source that was numerically derived from a nuclear reaction model originally developed at the Institute of Nuclear Researches of Moscow, Russia and implemented in the computer system at the University of Campinas, Brazil. Magnetospheric transport computations have been made covering the L-shell range L=1.0 to 1.6 and the resulting MeV He ion flux distributions show a strong influence of the local nuclear source mechanism on the inner zone energetic He ion content.

Cosmic Radiation↗
PubMed1998

Dynamics of the low altitude secondary proton radiation belt.

At the interface between the upper atmosphere and the radiation belt region, there exists a secondary radiation belt consisting mainly of energetic ions that have become neutralized in the ring current and the main radiation belt and then re-ionized by collisions in the inner exosphere. The time history of the proton fluxes in the 0.64-35 MeV energy range was traced in the equatorial region beneath the main radiation belts during the three year period from 21 February 1984 to 26 March 1987 using data obtained with the HEP experiment on board the Japanese OHZORA satellite. During most of this period a fairly small proton flux of -1.2 cm-2 S-1 sr-1 was detected on geomagnetic field lines in the range 1.05 < L < 1.15. We report a few surprisingly deep and rapid flux decreases (flux reduction by typically two orders of magnitude). These flux decreases were also long in duration (lasting up to three months). We also registered abrupt flux increases where the magnitude of the proton flux enhancements could reach three orders of magnitude with an enhancement duration of 1-3 days. Possible reasons for these unexpected phenomena are discussed.

Atmosphere↗
PubMed1998

[Comparative analysis of the VP2 variable region of the gene from infectious bursal disease virus isolates].

Variable cDNA regions in the VP2 gene of 24 isolates of infectious bursal disease virus (IBDV) isolated in Russia in 1993-1996 were amplified by the "nested" PCR and sequenced. The primary structure analysis of the VP2 gene variable region revealed 2 major groups of IBDV isolates. The first group consisted of the isolates with the structure identical or closely related to the highly virulent European strains CS89, 74/89A, 661, JY86, and DV86, the second group included the isolates with a high level of homology to the vaccine strains PBG98 and Cu-1. In addition, two isolates with original structure were identified, which differed from previously studied strains.

Amino Acid Sequence↗
PubMed1998

[Primary structure of gene H of cattle plague virus strain K].

Synthesis, cDNA cloning, and identification of H gene nucleotide sequence of rinderpest virus (RPV) K strain are carried out. Analysis of the identified nucleotide sequence has revealed the single open reading frame encoding a protein consisting of 609 amino acids with molecular weight of 68 kDa. The mean nucleotide homology between H genes of K, Kabete O and L strains in 88.0%, the mean amino acid homology of the corresponding proteins is 88.2%. RPV K strain hemagglutinin contains 5 potential glycosylation sites. The position of all 13 cystein bases is identical to positions in H proteins of RPV Kabete O and L strains. Studies of the hydrophobic profile of the compared proteins have shown 2 potential transmembrane fragments.

Animals↗
PubMed1998

[Molecular basis of changes in biological properties of foot and mouth disease virus of subtype A22].

Primary structure of capsid proteins and RNA polymerase of three closely related strains of foot and mouth disease virus (FMDV), subtype A22, differing by biological properties (the initial epitheliotropic strain A22 550 and its derivatives: thermoresistant myotropic A22 550/4 and thermosensitive attenuated A22 645) are compared by nucleic acid sequencing and analysis of the amino acid sequencing. The study revealed 1 substitute in VPI and 8 in RNA polymerase in the myotropic variant and 1 substitute in VP2, 2 in VP3, 13 in VP1, and 3 in RNA polymerase. Alteration of A22 550/4 tropism is probably due to a single substitution Gly 145-->Thr in the RGD site of capsid protein VP1. Analysis of the origin and biological properties of the attenuated strain A22 645 and the results of studies of the primary structure of proteins permit us to hypothesize that attenuation is polygenic, caused by adaptation to a heterologous host (continuous porcine cell culture), and can be expressed by changes in the structure of virus antireceptor providing its binding to cell receptors. Sites responsible for the reproduction of A22 FMDV at certain temperatures are presumably located in RNA polymerase.

Amino Acid Sequence↗
PubMed1997

[Automated cytophotomorphometric tests of blood smears in general clinical studies and population screening].

Automation of routine operations of photomorphometry of blood smears realized in the MEKOS-C cytoanalyzer helped create a new level of using a set of cytological tests, such as assessment of the leukocyte and erythrocyte formulae and of the histogram of hemoglobin distribution in red cells, estimation of leukocyte subtypes, assessment of the characteristics of the nucleolar system and the nucleoli-forming sites. Automated complex analysis of an increase in the measured characteristics of red and white blood cells impossible in common microscopy and flow cytoanalyzers appreciably improves the sensitivity and accuracy of tests and extends the range of their application. Low cost of analysis of a blood smear permits the use of MEKOS-C not only in clinical studies, but even in overall prophylactic screenings of the population.

Automation↗
PubMed1997

[A simple method for RNA isolation and purification].

RNAs from Escherichia coli cells, Syrian hamster kidney cells, foot-and-mouth disease virus, and Newcastle disease virus were isolated using glass fiber filters GF/F or GF/C. The RNA was reversibly adsorbed on the filters in the presence of 2 M guanidine thiocyanate and 50% ethanol (or isopropanol) and eluted with water. The fraction composition of the isolated RNA depended on the guanidine thiocyanate and alcohol concentrations in the adsorption and washing procedures. The RNA preparations obtained by this method can be used in reverse transcription and reverse transcription-polymerase chain reaction without additional purification.

Animals↗
PubMed1996

[Use of aerosol A-300 amd GF/F (GF/C) filters for purifying fragments of DNA, plasmid DNA, and RNA].

Aerosil A-300 and GF/F (GF/C) filters were used for purifying plasmid DNA and intact RNA as well as for the recovery of DNA fractionated on agarose gels. In the presence of guanidinium thiocyanate Aerosil A-300 and GF/F (GF/C) filters selectively bind nucleic acids, while proteins, agarose polysaccharides and salts are washed off. Nucleic acids desorbed from the Aerosil and filters are available immediately as substrates: DNA for restriction analysis, ligation and sequencing; RNA--for RT-PCR.

DNA↗
PubMed1992

[The previously unknown biological characteristics of the neurons of the paraventricular hypothalamic nucleus].

Structural sex-depended differences were revealed in 7 out of 10 hypothalamic paraventricular nuclei under study in DB/DB C57 BL-K56 mice. Sex-dependent differences were also found in the responses to diabetes mellitus in 6 of these nuclei. The data obtained seem to corroborate the sex dependence of the paraventricular-vagal neuronal system involved in the control of carbohydrate homeostasis.

Animals↗
PubMed1989

[Reaction of specific cell populations of hypothalamic paraventricular nuclei of the rat to carbohydrate loading and fasting].

The structural correlates of the cell responses in subnuclei of the hypothalamic paraventricular nuclei (PVN) in fasting and carbohydrate loaded adult male rats were studied using light microscopic morphometric methods. The data obtained revealed difference in responsiveness of the subnuclei studied to alternative shifts in the carbohydrate homeostasis: histophysiological features in five of ten cell-divisions, distinguished in the rat RVN, demonstrated their dependence on impaired carbohydrate homeostasis.

Animals↗
PubMed1988

[Functional status of the cardiovascular system in young persons with moderate arterial hypertension].

Hemodynamic and functional cardiac parameters were examined in 24 normal subjects and 43 patients with moderate arterial hypertension, grouped on the basis of their mean hemodynamic pressure. Considerable sex-specific differences were demonstrated in cardiovascular status and performance of both normal and hypertensive individuals. Young boys and girls showed different compensatory cardiac response to stressful pressure that may be attributed to different degrees of left-ventricular myocardial hypertrophy.

Adolescent↗