591 research outputs found
Theory of pattern-formation of metallic microparticles in poorly conducting liquid
We develop continuum theory of self-assembly and pattern formation in
metallic microparticles immersed in a poorly conducting liquid in DC electric
field. The theory is formulated in terms of two conservation laws for the
densities of immobile particles (precipitate) and bouncing particles (gas)
coupled to the Navier-Stokes equation for the liquid. This theory successfully
reproduces correct topology of the phase diagram and primary patterns observed
in the experiment [Sapozhnikov et al, Phys. Rev. Lett. v. 90, 114301 (2003)]:
static crystals and honeycombs and dynamic pulsating rings and rotating
multi-petal vortices.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Let
Velocity Distributions of Granular Gases with Drag and with Long-Range Interactions
We study velocity statistics of electrostatically driven granular gases. For
two different experiments: (i) non-magnetic particles in a viscous fluid and
(ii) magnetic particles in air, the velocity distribution is non-Maxwellian,
and its high-energy tail is exponential, P(v) ~ exp(-|v|). This behavior is
consistent with kinetic theory of driven dissipative particles. For particles
immersed in a fluid, viscous damping is responsible for the exponential tail,
while for magnetic particles, long-range interactions cause the exponential
tail. We conclude that velocity statistics of dissipative gases are sensitive
to the fluid environment and to the form of the particle interaction.Comment: 4 pages, 3 figure
Interacting circular nanomagnets
Regular 2D rectangular lattices of permalloy nanoparticles (40 nm in
diameter) were prepared by the method of the electron lithography. The
magnetization curves were studied by Hall magnetometry with the compensation
technique for different external field orientations at 4.2K and 77K. The shape
of hysteresis curves indicates that there is magnetostatic interaction between
the particles. The main peculiarity is the existence of remanent magnetization
perpendicular to easy plain. By numerical simulation it is shown, that the
character of the magnetization reversal is a result of the interplay of the
interparticle interaction and the magnetization distribution within the
particles (vortex or uniform).Comment: 16 pages, 8 figure
Cellular Models for River Networks
A cellular model introduced for the evolution of the fluvial landscape is
revisited using extensive numerical and scaling analyses. The basic network
shapes and their recurrence especially in the aggregation structure are then
addressed. The roles of boundary and initial conditions are carefully analyzed
as well as the key effect of quenched disorder embedded in random pinning of
the landscape surface. It is found that the above features strongly affect the
scaling behavior of key morphological quantities. In particular, we conclude
that randomly pinned regions (whose structural disorder bears much physical
meaning mimicking uneven landscape-forming rainfall events, geological
diversity or heterogeneity in surficial properties like vegetation, soil cover
or type) play a key role for the robust emergence of aggregation patterns
bearing much resemblance to real river networks.Comment: 7 pages, revtex style, 14 figure
The influence of defects on magnetic properties of fcc-Pu
The influence of vacancies and interstitial atoms on magnetism in Pu has been
considered in frames of the Density Functional Theory (DFT). The relaxation of
crystal structure arising due to different types of defects was calculated
using the molecular dynamic method with modified embedded atom model (MEAM).
The LDA+U+SO (Local Density Approximation with explicit inclusion of Coulomb
and spin-orbital interactions) method in matrix invariant form was applied to
describe correlation effects in Pu with these types of defects. The
calculations show that both vacancies and interstitials give rise to local
moments in -shell of Pu in good agreement with experimental data for
annealed Pu. Magnetism appears due to destroying of delicate balance between
spin-orbital and exchange interactions.Comment: 13 pages, 4 figure
Π Π΅Π³ΡΠ΅ΡΡΠΈΡ ΡΠ°ΡΠΊΠΎΠΌΡ ΠΠ°ΠΏΠΎΡΠΈ ΠΏΠΎΡΠ»Π΅ Π΄Π»ΠΈΡΠ΅Π»ΡΠ½ΠΎΠ³ΠΎ Π»Π΅ΡΠ΅Π½ΠΈΡ ΠΈΠ½Π³ΠΈΠ±ΠΈΡΠΎΡΠ°ΠΌΠΈ m-TOR ΠΈ ΠΏΠΎΠ»Π½ΠΎΠΉ ΠΎΡΠΌΠ΅Π½Ρ ΠΈΠΌΠΌΡΠ½ΠΎΡΡΠΏΡΠ΅ΡΡΠΈΠΈ Ρ ΡΠ΅ΡΠΈΠΏΠΈΠ΅Π½ΡΠ° ΠΏΠΎΡΠ»Π΅ ΡΡΠ°Π½ΡΠΏΠ»Π°Π½ΡΠ°ΡΠΈΠΈ ΠΏΠΎΡΠΊΠΈ
A case of observation of a patient who developed Kaposiβs sarcoma after kidney transplantation is presented. For the purpose of its treatment, conversion from tacrolimus to everolimus, courses of administration of prospidin were applied, in General, the intensity of immunosuppressive therapy was reduced. Stable remission was achieved only after removal of the renal transplant and complete withdrawal of immunosuppressive therapy.ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½ ΡΠ»ΡΡΠ°ΠΉ Π½Π°Π±Π»ΡΠ΄Π΅Π½ΠΈΡ ΠΏΠ°ΡΠΈΠ΅Π½ΡΠ°, Ρ ΠΊΠΎΡΠΎΡΠΎΠ³ΠΎ ΠΏΠΎΡΠ»Π΅ ΡΡΠ°Π½ΡΠΏΠ»Π°Π½ΡΠ°ΡΠΈΠΈ ΠΏΠΎΡΠΊΠΈ ΡΠ°Π·Π²ΠΈΠ»Π°ΡΡ ΡΠ°ΡΠΊΠΎΠΌΠ° ΠΠ°ΠΏΠΎΡΠΈ. Π‘ ΡΠ΅Π»ΡΡ Π΅Π΅ Π»Π΅ΡΠ΅Π½ΠΈΡ Π±ΡΠ»ΠΈ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½Ρ ΠΊΠΎΠ½Π²Π΅ΡΡΠΈΡ Ρ ΡΠ°ΠΊΡΠΎΠ»ΠΈΠΌΡΡΠ° Π½Π° ΡΠ²Π΅ΡΠΎΠ»ΠΈΠΌΡΡ, ΠΊΡΡΡΡ Π²Π²Π΅Π΄Π΅Π½ΠΈΡ ΠΏΡΠΎΡΠΏΠΈΠ΄ΠΈΠ½Π°, Π² ΡΠ΅Π»ΠΎΠΌ ΡΠΌΠ΅Π½ΡΡΠ΅Π½Π° Π½Π°ΠΏΡΡΠΆΠ΅Π½Π½ΠΎΡΡΡ ΠΈΠΌΠΌΡΠ½ΠΎΡΡΠΏΡΠ΅ΡΡΠΈΠ²Π½ΠΎΠΉ ΡΠ΅ΡΠ°ΠΏΠΈΠΈ. Π£ΡΡΠΎΠΉΡΠΈΠ²Π°Ρ ΡΠ΅ΠΌΠΈΡΡΠΈΡ Π΄ΠΎΡΡΠΈΠ³Π½ΡΡΠ° Π»ΠΈΡΡ ΠΏΠΎΡΠ»Π΅ ΡΠ΄Π°Π»Π΅Π½ΠΈΡ ΠΏΠΎΡΠ΅ΡΠ½ΠΎΠ³ΠΎ ΡΡΠ°Π½ΡΠΏΠ»Π°Π½ΡΠ°ΡΠ° ΠΈ ΠΏΠΎΠ»Π½ΠΎΠ³ΠΎ ΠΎΡΠΊΠ°Π·Π° ΠΎΡ ΠΈΠΌΠΌΡΠ½ΠΎΡΡΠΏΡΠ΅ΡΡΠΈΠ²Π½ΠΎΠΉ ΡΠ΅ΡΠ°ΠΏΠΈΠΈ
A hysteresis model with dipole interaction: one more devil-staircase
Magnetic properties of 2D systems of magnetic nanoobjects (2D regular
lattices of the magnetic nanoparticles or magnetic nanostripes) are considered.
The analytical calculation of the hysteresis curve of the system with
interaction between nanoobjects is provided. It is shown that during the
magnetization reversal system passes through a number of metastable states. The
kinetic problem of the magnetization reversal was solved for three models. The
following results have been obtained. 1) For 1D system (T=0) with the
long-range interaction with the energy proportional to , the
staircase-like shape of the magnetization curve has self-similar character. The
nature of the steps is determined by interplay of the interparticle interaction
and coercivity of the single nanoparticle. 2) The influence of the thermal
fluctuations on the kinetic process was examined in the framework of the
nearest-neighbor interaction model. The thermal fluctuations lead to the
additional splitting of the steps on the magnetization curve. 3) The
magnetization curve for system with interaction and coercivity dispersion was
calculated in mean field approximation. The simple method to experimentally
distinguish the influence of interaction and coercivity dispersion on the
magnetization curve is suggested.Comment: 22 pages, 8 figure
ΠΠΎΠΏΠ»Π΅ΡΠΎΠ²ΡΠΊΠΈΠΉ Π°ΡΡΠ΅ΡΠ°ΠΊΡ ΠΌΠ΅ΡΡΠ°Π½ΠΈΡ: ΡΠΈΠ·ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΌΠ΅Ρ Π°Π½ΠΈΠ·ΠΌΡ ΠΈ ΠΌΠ΅ΡΡΠΎ Π² Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΏΡΠ°ΠΊΡΠΈΠΊΠ΅. Π‘ΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠ΅ ΡΠΎΡΡΠΎΡΠ½ΠΈΠ΅ Π²ΠΎΠΏΡΠΎΡΠ°
The twinkling artifact has been known to specialists in ultrasound diagnostics since 1996. However, until now there is no understanding of the reasons for its appearance, and the place of its application in diagnostics.Material and methods. Electronic databases (PubMed, E-library, Web of Science) were searched studies using the keyword β βtwinkling artifactβ. The scientific publications on the Doppler twinkling artifact from the moment of the first reports about its existence is systematized and analyzed. The authors' own developments on this topic are presented. Modern views on this phenomenon and its place in ultrasound diagnostics are described. An explanation of the physical mechanisms of this phenomenon is given.Results. Recommendations are formulated for practitioners on changing the settings of an ultrasound scanner in order to increase twinkling artifact detectability. The directions of using the artifact to obtain additional diagnostic signs of pathological changes, which currently include the diagnosis of nephro-, uretero- and choledocholithiasis, are determined.Conclusions. The high efficiency of the use of the twinkling artifact for the diagnosis of small kidney stones, comparable with the capabilities of computed tomography, has been shown. Β ΠΠ²Π΅Π΄Π΅Π½ΠΈΠ΅. ΠΡΡΠ΅ΡΠ°ΠΊΡ ΠΌΠ΅ΡΡΠ°Π½ΠΈΡ ΠΈΠ·Π²Π΅ΡΡΠ΅Π½ ΡΠΏΠ΅ΡΠΈΠ°Π»ΠΈΡΡΠ°ΠΌ ΡΠ»ΡΡΡΠ°Π·Π²ΡΠΊΠΎΠ²ΠΎΠΉ Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΠΊΠΈ Ρ 1996 Π³. ΠΠ΄Π½Π°ΠΊΠΎ Π΄ΠΎ Π½Π°ΡΡΠΎΡΡΠ΅Π³ΠΎ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ Π½Π΅Ρ ΠΎΠ΄Π½ΠΎΠ·Π½Π°ΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΠ½ΠΈΠΌΠ°Π½ΠΈΡ ΠΊΠ°ΠΊ ΡΠΈΠ·ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΎΡΠ½ΠΎΠ² Π΅Π³ΠΎ ΠΏΠΎΡΠ²Π»Π΅Π½ΠΈΡ, ΡΠ°ΠΊ ΠΈ ΠΎΠ±Π»Π°ΡΡΠ΅ΠΉ ΡΠ»ΡΡΡΠ°Π·Π²ΡΠΊΠΎΠ²ΠΎΠΉ Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΠΊΠΈ, Π³Π΄Π΅ Π²ΡΡΠ²Π»Π΅Π½ΠΈΠ΅ Π΅Π³ΠΎ Π½Π΅ΡΠ΅Ρ ΡΠ΅Π°Π»ΡΠ½ΡΡ Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΡΠ΅ΡΠΊΡΡ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΡ.ΠΠ°ΡΠ΅ΡΠΈΠ°Π» ΠΈ ΠΌΠ΅ΡΠΎΠ΄Ρ. Π ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΡΡ
Π±Π°Π·Π°Ρ
Π΄Π°Π½Π½ΡΡ
(PubMed, E-library, Web of Science) Π±ΡΠ» ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ ΠΏΠΎΠΈΡΠΊ ΠΎΠΏΡΠ±Π»ΠΈΠΊΠΎΠ²Π°Π½Π½ΡΡ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ ΠΏΠΎ ΠΊΠ»ΡΡΠ΅Π²ΡΠΌ ΡΠ»ΠΎΠ²Π°ΠΌ βtwinkling artifactβ, βΠΌΠ΅ΡΡΠ°ΡΡΠΈΠΉ Π°ΡΡΠ΅ΡΠ°ΠΊΡβ, βΠ°ΡΡΠ΅ΡΠ°ΠΊΡ ΠΌΠ΅ΡΡΠ°Π½ΠΈΡβ. Π‘ΠΈΡΡΠ΅ΠΌΠ°ΡΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Π° ΠΈ ΠΏΡΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Π° ΠΈΠΌΠ΅ΡΡΠ°ΡΡΡ Π½Π°ΡΡΠ½Π°Ρ Π»ΠΈΡΠ΅ΡΠ°ΡΡΡΠ°, ΠΏΠΎΡΠ²ΡΡΠ΅Π½Π½Π°Ρ Π΄ΠΎΠΏΠ»Π΅ΡΠΎΠ²ΡΠΊΠΎΠΌΡ Π°ΡΡΠ΅ΡΠ°ΠΊΡΡ ΠΌΠ΅ΡΡΠ°Π½ΠΈΡ Ρ ΠΌΠΎΠΌΠ΅Π½ΡΠ° ΠΏΠ΅ΡΠ²ΡΡ
ΠΏΡΠ±Π»ΠΈΠΊΠ°ΡΠΈΠΉ ΠΎ Π΅Π³ΠΎ ΡΡΡΠ΅ΡΡΠ²ΠΎΠ²Π°Π½ΠΈΠΈ. ΠΡΠΌΠ΅ΡΠ΅Π½Ρ ΡΠΎΠ±ΡΡΠ²Π΅Π½Π½ΡΠ΅ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠΈ Π½Π° ΡΡΡ ΡΠ΅ΠΌΡ. ΠΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Ρ ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΡΠ΅ Π²Π·Π³Π»ΡΠ΄Ρ Π½Π° Π΄Π°Π½Π½ΠΎΠ΅ ΡΠ²Π»Π΅Π½ΠΈΠ΅ ΠΈ Π΅Π³ΠΎ ΠΌΠ΅ΡΡΠΎ Π² ΡΠ»ΡΡΡΠ°Π·Π²ΡΠΊΠΎΠ²ΠΎΠΉ Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΠΊΠ΅. ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Π° ΠΎΡΠ½ΠΎΠ²Π½Π°Ρ Π½Π° Π½Π°ΡΡΠΎΡΡΠΈΠΉ ΠΌΠΎΠΌΠ΅Π½Ρ Π²Π΅ΡΡΠΈΡ ΠΎ ΠΏΡΠΈΡΠΈΠ½Π°Ρ
Π²ΠΎΠ·Π½ΠΈΠΊΠ½ΠΎΠ²Π΅Π½ΠΈΡ Π΄Π°Π½Π½ΠΎΠ³ΠΎ ΡΠ²Π»Π΅Π½ΠΈΡ.Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ. Π‘ΡΠΎΡΠΌΡΠ»ΠΈΡΠΎΠ²Π°Π½Ρ ΡΠ΅ΠΊΠΎΠΌΠ΅Π½Π΄Π°ΡΠΈΠΈ Π΄Π»Ρ ΠΏΡΠ°ΠΊΡΠΈΡΠ΅ΡΠΊΠΈΡ
Π²ΡΠ°ΡΠ΅ΠΉ ΠΏΠΎ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΡ Π½Π°ΡΡΡΠΎΠ΅ΠΊ ΡΠ»ΡΡΡΠ°Π·Π²ΡΠΊΠΎΠ²ΠΎΠ³ΠΎ ΡΠΊΠ°Π½Π΅ΡΠ° Ρ ΡΠ΅Π»ΡΡ ΠΏΠΎΠ²ΡΡΠ΅Π½ΠΈΡ Π²ΡΡΠ²Π»ΡΠ΅ΠΌΠΎΡΡΠΈ Π°ΡΡΠ΅ΡΠ°ΠΊΡΠ° ΠΌΠ΅ΡΡΠ°Π½ΠΈΡ. ΠΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Ρ Π½Π°ΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΡ Π°ΡΡΠ΅ΡΠ°ΠΊΡΠ° Π΄Π»Ρ ΠΏΠΎΠ»ΡΡΠ΅Π½ΠΈΡ Π΄ΠΎΠΏΠΎΠ»Π½ΠΈΡΠ΅Π»ΡΠ½ΡΡ
Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΏΡΠΈΠ·Π½Π°ΠΊΠΎΠ² ΠΏΠ°ΡΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠΉ, ΠΊ ΠΊΠΎΡΠΎΡΡΠΌ Π² Π½Π°ΡΡΠΎΡΡΠ΅Π΅ Π²ΡΠ΅ΠΌΡ ΠΎΡΠ½ΠΎΡΡΡ Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΠΊΡ Π½Π΅ΡΡΠΎ-, ΡΡΠ΅ΡΠ΅ΡΠΎ- ΠΈ Ρ
ΠΎΠ»Π΅Π΄ΠΎΡ
ΠΎΠ»ΠΈΡΠΈΠ°Π·Π°.ΠΠ°ΠΊΠ»ΡΡΠ΅Π½ΠΈΠ΅. ΠΡΠΌΠ΅ΡΠ΅Π½Π° Π²ΡΡΠΎΠΊΠ°Ρ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΡ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΡ Π°ΡΡΠ΅ΡΠ°ΠΊΡΠ° ΠΌΠ΅ΡΡΠ°Π½ΠΈΡ Π΄Π»Ρ Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΠΊΠΈ ΠΌΠ΅Π»ΠΊΠΈΡ
ΠΊΠ°ΠΌΠ½Π΅ΠΉ ΠΏΠΎΡΠ΅ΠΊ, ΡΠΎΠΏΠΎΡΡΠ°Π²ΠΈΠΌΠ°Ρ Ρ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡΠΌΠΈ ΠΊΠΎΠΌΠΏΡΡΡΠ΅ΡΠ½ΠΎΠΉ ΡΠΎΠΌΠΎΠ³ΡΠ°ΡΠΈΠΈ. ΠΠΎΠΊΠ°Π·Π°Π½Π° Π½ΠΈΠ·ΠΊΠ°Ρ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΈΠ²Π½ΠΎΡΡΡ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΡ Π°ΡΡΠ΅ΡΠ°ΠΊΡΠ° Π΄Π»Ρ Π²ΡΡΠ²Π»Π΅Π½ΠΈΡ ΠΌΠΈΠΊΡΠΎΠΊΠ°Π»ΡΡΠΈΠ½Π°ΡΠΎΠ² ΠΌΠΎΠ»ΠΎΡΠ½ΠΎΠΉ ΠΆΠ΅Π»Π΅Π·Ρ ΠΈ ΠΎΠ±ΡΠ·Π²Π΅ΡΡΠ²Π»Π΅Π½ΠΈΠΉ Π΄ΡΡΠ³ΠΈΡ
Π°Π½Π°ΡΠΎΠΌΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΡΡΡΠΊΡΡΡ
Meglumine Sodium Succinate to Correct COVID-19-Associated Coagulopathy: the Feasibility Study
Aim of the study: to evaluate the effect of meglumine sodium succinate (MSS) on the efficacy of anticoagulant therapy in patients with severe COVID-19 infection complicated by bilateral community-acquired pneumonia.Materials and methods. Overall efficacy of treatment was analyzed in 12 patients hospitalized to ICU with the diagnosis of severe confirmed COVID-19 coronavirus infection (U07.1) complicated by bilateral multisegmental pneumonia. All patients received prophylactic anticoagulation with unfractionated heparin. The patients were divided into two groups: 7 of them received a multi-electrolyte solution containing MSS 5 ml/kg daily for the entire ICU stay (3-10 days) as a part of therapy; 5 patients received a similar volume of a conventional multi-electrolyte solution containing no metabolically active substrates and comprised a control group. Coagulation parameters were measured in arterial and venous blood of all patients at the following stages: 1) upon admission to the ICU; 2) 2-4 hours after the first dose of heparin; 3) 8-12 hours after the second dose of heparin; 4) 24 hours after the beginning of intensive therapy. On the 28th day of follow-up, mortality, duration of ICU stay, and incidence of thrombotic complications in the groups were evaluated. Nonparametric methods of statistical analysis were used to assess intragroup changes and intergroup differences.Results. The group of patients administered with MSS had significantly fewer thromboembolic events during 28 days of treatment and shorter ICU stay. These patients responded faster to anticoagulant therapy, which was suggested by more distinct changes in coagulation parameters, i.e. increased APTT, persisting viable thrombocyte population, reduced D-dimer and fibrinogen levels.Conclusion. The metabolic action of succinate possibly increases endothelial resistance to damaging factors and reduces its procoagulant activity. The hypothesis requires testing in a larger clinical study with a design including laboratory evaluation of the efficacy of varying doses of the studied drug as well as aiming at elucidation of the mechanisms of its effect on specific pro- and anticoagulation system components
Human NK cells internalize recombinant major stress protein HSP70
Heat shock proteins 70 kDa (HSP70) protect intracellular proteins from the damaging effects of stress factors of various natures. Moreover, HSP70 play an important role in the vital activity of cells under normal physiological conditions, performing chaperone functions. These functions are realized in the intracellular space; however, in some cases, these proteins are also found on the cell surface and in the extracellular environment. The causes and mechanisms of HSP70 translocation to the cell surface and secretion into the extracellular space have not yet been well understood, but such an unusual localization of HSP70 activates the immune system. The surface HSP70 and their extracellular pool stimulate the cytotoxic activity of NK cells. However, direct experimental evidence for the internalization of HSP70 molecules by NK cells has not yet been demonstrated. This paper presents the results of the interaction of the extracellular HSP70 pool with NK cells from the peripheral blood. The results demonstrated the confirmation of the internalization of exogenous HSP70 molecules by NK cells. To this end, fluorescently labeled recombinant stress-inducible human HSP70 were obtained. The electrophoretic data indicated the absence of protein degradation during the labeling process, the purity and stability of the modified protein. To assess the interaction of HSP70 with NK cells, the fluorescently labeled HSP70 was added to an in vitro culture of NK cells isolated by magnetic separation from the peripheral blood mononuclear fraction and analyzed by confocal microscopy. This analysis indicated that living NK cells internalize extracellular HSP70 with localization both in lysosomes and in phagosomes. Our experiments illustrated for the first time the process of penetration of the extracellular form of HSP70 into these cells. The results suggest that the activation of NK cells under the action of exogenous HSP70 could be associated with the internalization of these protein molecules
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