Expression of the BCR-ABL1 Gene in Patients with Chronic Myeloproliferative Diseases with Signs of Progression

Background. The V617F mutation of JAK2 is known to manifest in Ph-negative chronic myeloproliferative diseases (cMPD), such as polycythemia vera, thrombocythemia, and myelofibrosis. These diseases not infrequently advance into more aggressive forms up to acute leukemia. As the progression mechanism is still unknown, its study retains a high priority. JAK2 carrying the V617F mutation is believed to cause constant activation of V(D)J recombinase in myeloid tumor cells in cMPD patients. Aberrant activation of V(D)J recombinase in tumor cells in cMPD patients can lead to t(9;22)(q34;q11) chromosomal rearrangement. Aim. To study the expression of BCR-ABL1 resulting from translocation t(9;22)(q34;q11) in cMPD patients at the progression stage in order to test the suggested hypothesis. Materials & Methods. The BCR–ABL1 expression was assessed in peripheral blood granulocytes in cMPD patients by real-time PCR. The JAK2 V617F mutation was identified by quantitative allele-specific PCR. The JAK2 exon 12 mutations were determined using Sanger direct sequencing of PCR products. Results. The BCR-ABL1 expression was discovered in 29 % of patients with cMPD progression. The BCR-ABL1 expression in these patients correlated with hepatosplenomegaly and hyperleukocytosis. Conclusion. In a significant proportion of cMPD patients the disease progression can be associated with activation of the BCR-ABL expression

Three-dimensional MHD simulations of forced magnetic reconnection

Results are presented from MHD simulations of three-dimensional flows of a high-conductivity plasma in the vicinity of a null point of a magnetic field. The excitation of an electric current at the boundary of the computation region results in self-consistent plasma flows and change in the structure of the magnetic field. Generally, in the vicinity of a null point, an MHD singularity arises that manifests itself in the formation of locally plane current sheets. It is shown that the current sheet can be oriented either along the separatrix surface of a magnetic configuration or perpendicular to it, except for axisymmetric configurations (or close to them), when the excitation of an electric current in the direction orthogonal to the separatrix surface does not lead to the formation of a current sheet. (C) 2001 MAIK "Nauka/Interperiodica"

Formation of current sheets in structurally stable and structurally unstable magnetic configurations with two null lines

The nonlinear dynamics of magnetoacoustic and Alfven Mt-ID perturbations in structurally unstable magnetic configurations with two null lines (X-lines) is studied both analytically and numerically. It is shown that these perturbations cause the electric current to evolve nonlinearly in such a manner that a structurally unstable configuration of the magnetic field transforms into a structurally stable configuration. Such a transformation is forbidden in ideal magnetohydrodynamics but can occur in the process of magnetic field line reconnection. The final magnetic configuration to which the system evolves is shown to contain no separatrices connecting the null lines. (C) 2000 MAIK "Nauka/Interperiodica"

Relativistic electron mirrors from nanoscale foils for coherent frequency upshift to the extreme ultraviolet

Reflecting light from a mirror moving close to the speed of light has been envisioned as a route towards producing bright X-ray pulses since Einstein’s seminal work on special relativity. For an ideal relativistic mirror, the peak power of the reflected radiation can substantially exceed that of the incident radiation due to the increase in photon energy and accompanying temporal compression. Here we demonstrate for the first time that dense relativistic electron mirrors can be created from the interaction of a high-intensity laser pulse with a freestanding, nanometre-scale thin foil. The mirror structures are shown to shift the frequency of a counter-propagating laser pulse coherently from the infrared to the extreme ultraviolet with an efficiency >10(4) times higher than in the case of incoherent scattering. Our results elucidate the reflection process of laser-generated electron mirrors and give clear guidance for future developments of a relativistic mirror structure

Reconnection of magnetic field lines near critical points

A review of theoretical studies and computer simulations of the plasma dynamics near critical points of the magnetic field is presented. The global characteristics of reconnection of the magnetic field lines and vortex lines are discussed. Examples of typical patterns of the magnetic field near critical points are presented. The propagation of MHD waves and the formation of singularities near null lines and separatrix surfaces are discussed. Nonlinear regimes of the plasma dynamics are described, and exact solutions of the MHD equations in which the Hall effect is taken into account are presented. The magnetic reconnection in the frame of the electron magnetohydrodynamics model is also discussed. The results of computer simulations of the current sheet formation near null lines and separatrices of the magnetic field are presented. The nonadiabatic motion and the acceleration of charged particles near critical points are discussed