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A V Filatov

Publications and source records attributed to A V Filatov.

At least 37 records · Page 2Linked to original sources
PubMed1986

[Migration of T-lymphocyte precursors into the thymus and the factors affecting this process].

Migration of FITC-labeled mouse bone marrow cells into the thymus was measured by flow cytometric analysis 3 hours after intravenous injection of cells into irradiated mice. The percentage of cells reaching the thymus diminished when the dose of injected cells increased. The dependence of the number or labeled cells in the thymus on the dose of injected cells was not linear. Pretreatment of cells with anti-SC-I serum, peanut lectin or H-2 incompatibility antigen abolished thymus migration, while treatment with anti-Thy-I serum, soybean lectin, trypsin or Thy-I-incompatibility antigen diminished cellular migration and treatment with neuraminidase enhanced it. It was concluded that the main type of migrating cells is SC-1+ precursors of T-lymphocytes. Penetration of these cells through the blood-thymus barrier is based on the recognition of their partly sialized surface glycoprotein receptors by membrane lectins of the blood-thymus barrier cells.

Animals↗
PubMed1986

[Characteristics of the T-lymphocytes interacting with hematopoietic stem cells: the expression of Lyt-3 antigen].

The lymph node cells were treated with monoclonal anti-Lyt-3 antibodies (anti-Lyt-3) and complement. Their interaction with colony-forming units (CFU) of bone marrow was studied. Anti-Lyt-3 did not affect the activity of T-lymphocytes, which changed the pattern of syngenic CFU differentiation in spleen of irradiated mice. On the contrary, the activity of T-lymphocytes, which inactivated proliferation and differentiation of non-syngenic CFU in spleen, was decreased. In the peritoneal cavity of irradiated mice antibodies did not affect the activity of T-lymphocytes which suppressed the colony-formation of non-syngenic stem cells and switched off the activity of T-lymphocytes that stimulated syngenic CFU colony-formation. The subpopulation characteristics of regulatory and effector T-cells has been analysed.

Animals↗
PubMed1985

Monoclonal antibodies against common and Igk-1a allotypic determinants of rat immunoglobulin kappa chain constant domain.

SJL/J mice were immunized with polyclonal rat Ig light chains of two allotypes and immune spleen cells were fused with P3-Ag8.653 myeloma cells. 17 cell populations producing antirat Ig AB were cloned. Four clones, 1G9, L3E8, L2B2 and L2C5 have been characterized in detail. All MABs are of the IgG1, kappa isotype. Using monoclonal rat kappa chains it was demonstrated that all the AB react with rat Ig kappa chains. Further localization of antigenic determinants was performed using isolated L chain C domain. It was shown that all MABs are directed against C domain epitopes. L2C5 MAB binds selectively to August rat L chains, thus showing specificity for Igk-1a determinants. The remaining three clones bind equally well to L chains of different allotypes, but 1G9 clone binds preferentially to isolated L chains as compared to intact IgG molecules.

Animals↗
PubMed1985

[Importance of adrenoreactive vessels in the mechanisms of the vasoconstrictor response to hyperoxia].

Experiments in 116 white rats showed that high--pressure oxygen (3 beta 3.9 kPa--50 min) increased the adrenoreactivity of vessels under stimulation of alpha--adrenoreceptors with mesaton (phenylephrine) and lost this ability after blockade with pyroxan. The vasoconstricting response (the increase of blood pressure and of general peripheral resistance of vessels) seem to stem from interaction of high--pressure oxygen with post--synaptic alpha--adrenoreceptors of vessels.

Adrenergic alpha-Agonists↗
PubMed1985

[Participation of peptide mechanisms in physiological reactions of the cardiovascular system to hyperoxia].

Experimental study in 156 white rats with renovascular hypertension, posthemorrhagic hypotension and with normal blood pressure revealed that high--ressure oxygen (303.9 kPa--50 min) could activate angiotensin--converting enzyme, the latter taking part in inactivation of endogenous opioid peptides. Involvement of peptide--like links in hemodynamic responses to hyperoxia seems to be an important component of the mechanism of oxygen action upon the cardiovascular system.

Animals↗
PubMed1985

[Quantitative evaluation and prognosis of the biological effects of hyperoxia].

Experiments in 104 white mice subjected to hyperoxia at different regimens of oxygenation, carried out by means of mathematical modelling of three hyperoxic effects (bradypnea, convulsions, lethality) revealed the dependence of biological (physiological, toxic) effects of hyperoxia upon both components of the oxygenation regimen (oxygen pressure, time of exposure). The proposed concept of integral dose allows to determine pressure-exposure correlations corresponding to a given biological phenomenon and to prognosticate the effects of hyperoxia.

Animals↗
PubMed1984

[Structural and functional study of acidification in the process of phagocytosis].

Morphometry and cytofluorometry of the kinetics of phagocytosis were applied to study the quantitative mechanisms of acidification in the area of contact between the plasma membrane of macrophages and Candida albicans yeast cells conjugated with fluorescein isothiocyanate. It was found by stereological transformation of the morphometry data that the main part of macrophages phagocytose the limiting amount of particles by minute 5-10. A good agreement was established between the cytofluorometric histograms and the stereological data. This made it possible to evaluate, using the calibration curve, the pH on the surface of the phagocytosed material based on the fluorescence quenching. As an advantage of the suggested comprehensive approach to the study of acidification, the authors stress the possibility of making structural-functional analysis of the rearrangements occurring in the intact phagocytosing cell.

Animals↗
PubMed1984

[Isolation of monoclonal antibodies to antigen Lyt-3.2].

A hybridoma producing monoclonal antibodies (McAb) NATF9.9 (F9) was obtained from fusion of murine myeloma X63 and splenocytes of AKR mice immunized with a single intravenous injection of 5 X 10(7) thymocytes of CBA mice. F9 McAb were cytotoxic for 80% thymocytes, 10% splenocytes, 20% lymph node cells, 85% cortical and 32% medullary thymocytes of CBA, C57BL/6, BALB/c, DBA/2 and SJL but not for the cells of C58 and AKR mice. F9 McAb reacted only with T cells and did not react with B cells and EL4 thymoma cells (Thy-1.2+, Lyt-1+2-3-). The proportion of F9+ cells accounts for about 40% among T lymphocytes of the lymph nodes and spleen as tested by flow-type cytometry. Lymph node cells treated with F9 McAb plus complement completely lost their reactivity with rat anti-Lyt-2 McAb and only partly (by 30%) with anti-Lyt-1 McAb. The reactivity pattern of F9 McAb attests to their specificity for Lyt-3.2 antigen.

Animals↗
PubMed1984

[Use of monoclonal antibodies against the light-chain immunoglobulins of the rat in the radioimmune analysis of differentiated lymphocyte antigens of the mouse].

Spleen cells from SJL mice immunized with rat immunoglobulin light chains were fused with X-63 myeloma. Seven hybridoma lines were obtained. Monoclonal antibodies (McAB) secreted by lines L1G9, L2B2 and L3E8 were purified and labeled by 125I. McAB L1G9 did not bind directly to murine lymphocytes but reacted in a different manner with rat splenocytes. McAb L2B2 and L3E8 but not L1G9 reacted with murine lymphocytes treated with rat McAb against Lyt-1, Lyt-2, C1-9, C4-20 antigens whatever the class of heavy chains of rat McAb used. The binding levels obtained with 125I-McAb reflect the quantitative differences in the expression of respective antigens.

Animals↗
PubMed1984

[Detection and isolation of antibody-forming clones by means of local cytolysis in gel].

A method is suggested combining the screening and cloning of hybridomas producing cytotoxic antibodies. The method is based on the Erne local hemolysis principles. The cells from the preformed hybridoma line NATF 9.9 secreted monoclonal antibodies (McAb) against murine T lymphocyte differentiation antigen Lyt-3.2. A mixture of hybridoma cells and target cells was attached to the plastic Petri dish surface pretreated with Poly-L-lysine and covered with agarose. McAb production by hybridoma cells was elicited by complement-dependent lysis of target cells. The lysis was detected by incorporation in dead cells of the fluorescent dye ethidium bromide. Subsequent studies made it possible to evaluate the clonogenic capacity of McAb production and isolate active clones.

Animals↗
PubMed1983

[Acidification kinetics in macrophage phagosomes based on flow cytometric data].

Using flow cytofluorimetry, acidification in macrophages was studied during phagocytosis of yeast cells Candida albicans conjugated with FITC. Two phases of acidification were found: one corresponding presumably to yeast cell absorption on the macrophage surface, and the other one being due to cell incorporation into phagolysosomes. The phases are characterized by pH values of 6.3 +/- 0.5 and 4.5 +/- 0.5, respectively. Addition of 10 mM NH4Cl cancelled the observed acidification, whereas the presence of cytochalasin B (2 . 10(-5) M) prevented the very process of acidification.

Animals↗
PubMedDate not supplied

[Study of the conformational mobility of globular proteins by pulse methods of NMR].

The protein spin-echo decay and recovery of longitudinal magnetization were studied in seven globular proteins: cytochrome C, ribonuclease, lysozyme, DNA, hemoglobin, serum albumin and gamma-globulin in D2O solutions. For comparison the Tobacco mosaic virus (TMV) protons in D2O solutions were also investigated. The spin-echo decay of all 7 proteins can be separated into three components: a slowly decaying component with an amplitude of about 10% of the amplitude of the total signal, intermediately and fastly decaying components, the two latter being comparable in amplitudes. Longitudinal relaxation is more simple in character. The value of T2 of the protons responsible for the fastly decaying components in linearly dependent on the molecular weight of the protein, a fact indicating that the regions of the proteins with a "rigid" structure can be responsible for this component. The intermediate component, whose contribution increases with temperature, was ascribed to the mobile regions of the protein, and the slowly decaying component to the mobile protein side chains. Weak dependence of T1 on the protein molecular weight and some other obtained data give additional evidence for the presence of motion within macromolecules. The peculiarities of this motion is in good correspondence with the notion about the existence of the segmental motion of the polypeptide chain (conformational mobility of the protein). In contrast to proteins the spin-echo decay of TMV lacked the slow component and the "solid" echo signal was observed which indicates the existence of a "rigid" structure in the macromolecules of the virus.

Cytochrome c Group↗
PubMedDate not supplied

[An experimental biotechnical system for determining an index of toxicity].

The system of bioengineering for determination of toxicity index with bovine spermatozoal suspension as a primary transducer was developed. The toxicity index is determined according to a change in spermatozoal suspension mobility defined with the help of an optoelectronic device. The system of bioengineering is used for determination of toxicity index of polymers for medical applications.

Animals↗
PubMedDate not supplied

[Internal movement within globular proteins in accordance with the relationship between temperature and spin-lattice relaxation time].

The minima on the temperature dependence of T1 for protein protons were observed in dried SA at temperature about -100 degrees C and also about 0 degree C in SA and RNAase solutions in D2O. The minima of the temperature dependence were ascribed to motions of methyl groups of proteins, in the first case, and to oscillation of the polypeptide chain in the second case, both at characteristic frequencies of 10(8) s-1 in the minimum points.

Deuterium↗
PubMedDate not supplied

[Comparative study of the characteristics of the proton NMR spin echo decay of different globular proteins in water].

Spin-echo decays were studied for protons of 7 enzymes and 4 other globular proteins. Similar decay behaviour of the skin-echo decay curves was observed for all non-enzymatic proteins (motion of protein globules as whole units was taken into account). The spin-echo decay surves of 5 monomeric enzymes also exhibited very close decay patterns, although they decayed more slowly than non-enzymatic proteins. Greater slowing of the decay was observed for proton spin echoes in two subunit enzymes. Observed slowing of the decay is interpreted in terms of more intense inner motions within the macromolecules of enzymes, compared to non-enzymes. In subunit enzymes it occurs in addition because of the motion of separate units.

Magnetic Resonance Spectroscopy↗
PubMedDate not supplied

[Study of the conformational mobility of globular proteins in aqueous solutions according to their proton relaxation in a rotating system of coordinates].

Measurements of the nuclear magnetization decay in the rotating frame for protons of SA and RNAase proteins in aqueous solutions indicate the dispersion of the relaxation rate for SA protons within the region of correlation frequencies of 10(5)--10(6) s-1. These frequencies are much lower than frequencies of rotational diffusion movements of the SA macromolecules in aqueous solutions. These must be ascribed to internal movement within protein globules due to which the distances between interacting magnetic moments are changed. This conclusion gives direct evidence in favour of existence of conformational mobility in most of the protein globule volume.

Animals↗