Advanced lymphoblastic clones detection in T-cell leukemia

T cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignant neoplasm of the lymphocyte precursors that suffered malignant transformation arresting the lymphoid cell differentiation. Clinical studies revealed monoor, more rarely, oligoclonal nature of the disease. A precise identification of malignant clone markers is both the crucial stage of early diagnostics and the essential prognostic factor for therapeutic treatment. Here we present an improved system for unbiased detection of lymphoblastic clones in bone marrow aspirates of T-ALL patients. The system based on multiplex PCR of rearranged T-cell receptor locus (TRB) and straightforward sequencing of the resulted PCR fragments. Testing of the system on genomic DNA from Jurkat cell line and four clinical bone marrow aspirates revealed a set of unique TRB rearrangements that precisely characterize each of tested samples. Therefore, the outcome of the system produces highly informative molecular genetic markers for further monitoring of minimal residual disease in T-ALL patients.     

Cell Elasticity Is Regulated by the Tropomyosin Isoform Composition of the Actin Cytoskeleton

The actin cytoskeleton is the primary polymer system within cells responsible for regulating cellular stiffness. While various actin binding proteins regulate the organization and dynamics of the actin cytoskeleton, the proteins responsible for regulating the mechanical properties of cells are still not fully understood. In the present study, we have addressed the significance of the actin associated protein, tropomyosin (Tpm), in influencing the mechanical properties of cells. Tpms belong to a multi-gene family that form a co-polymer with actin filaments and differentially regulate actin filament stability, function and organization. Tpm isoform expression is highly regulated and together with the ability to sort to specific intracellular sites, result in the generation of distinct Tpm isoform-containing actin filament populations. Nanomechanical measurements conducted with an Atomic Force Microscope using indentation in Peak Force Tapping in indentation/ramping mode, demonstrated that Tpm impacts on cell stiffness and the observed effect occurred in a Tpm isoform-specific manner. Quantitative analysis of the cellular filamentous actin (F-actin) pool conducted both biochemically and with the use of a linear detection algorithm to evaluate actin structures revealed that an altered F-actin pool does not absolutely predict changes in cell stiffness. Inhibition of non-muscle myosin II revealed that intracellular tension generated by myosin II is required for the observed increase in cell stiffness. Lastly, we show that the observed increase in cell stiffness is partially recapitulated in vivo as detected in epididymal fat pads isolated from a Tpm3.1 transgenic mouse line. Together these data are consistent with a role for Tpm in regulating cell stiffness via the generation of specific populations of Tpm isoform-containing actin filaments.     

Development of a pseudointima in a synthetic prosthesis in experimental hypercholesterolemia]

Under study was the dynamics of formation of pseudointima in a synthetic lavsan prosthesis of the aorta of 32 rabbits, 22 of them were on the atherogenic diet. Against the background of experimental hypercholesterolemia the proliferation of cells and the obliteration of the vessel lumen were found to proceed more rapidly than in normal animals.     

Monoclonal antibodies inhibiting RNA polymerase from Escherichia coli

Monoclonal hybridoma antibodies directed against RNA polymerase from E. coli have been obtained. Only a few have been found to inhibit the enzyme activity. Antibodies produced by two clones, PYN-1 and PYN-2, inhibit RNA polymerase at the stage of RNA chain elongation. The PYN-1 antibodies react with the beta'-subunit of the enzyme. The PYN-2 antibodies react with the beta-subunit and with its 130 kDa amber fragment.     

Epidemiological problems of ozena and the means for controlling this infection

Clinical, bacteriological, serological and epidemiological studies of ozena morbidity among the population of Minsk were carried out in 1970-1980. On January 1, 1981, the ozena morbidity rate among the inhabitants of Minsk was 26.72%. Ozena was found to affect mainly children and women. A wide spread of the family foci of this disease (31.68%) was revealed. The results of this study indicate that the source of K. ozaenae is a sick person who begins to excrete the bacteria in the prodromal period of the disease and may continue to excrete them for many years. The transfer of K. ozaenae occurs probably by droplet or contact infection. The droplet infection is less active in the absence of symptoms (coughing, sneezing) facilitating excretion of the infective agent into the air and in cases of the low susceptibility of persons to ozena. The main measures for controlling ozena are the timely detection and sanitation of the sources of ozena, as well as the current disinfection of the infection foci in apartments.     

Experimental evidence of the defense role of the exocyst in the metacestode of <Emphasis Type="Italic">Microsomacanthus lari</Emphasis> Belogurov et Kulikov,in Spasskaja, 1966 (Cestoda: Hymenolepididae)

The interaction of intermediate host (Eogammarus tiuschovi) cells with the cysticercoid of Microsomacanthus lari of the cyclocercus type was examined for the case of damage of the noncellular exocyst surrounding it. Massive penetration of the host cells, supposedly haemocytes characterized by intensive secretion, into the exocyst was observed even during the first several minutes of the experiment. Large accumulations of the product of secretion (fibrous material) were concentrated in the distal areas of the endocyst glycocalix and the microvillar layer of the cysticercoid tail appendage. The results provide evidence for the defensive role of the exocyst of M. lari in the cellular response of an intermediate host organism to invasion.     

Spontaneous aneuploidy level in blood cells of fertile females

In this study, we presented results of molecular cytogenetic assay of blood cells of fertile women of reproductive age. Cultivated and uncultivated cells and two sets of FISH probes with direct and indirect labeling were used. The middle level of aneuploidy for four chromosomes and statistical limits for aneuploidy detection were estimated. Aneuploidy determined with direct multicolor FISH in cultivated lymphocytes varied from 0.1 to 1.3%. The middle level of aneuploidy for all four chromosomes (13, 18, 21, and X) was 1.39%. The limit of mutation detection was 3.4%. We found differences in results with direct and indirect labeling. It was shown that the cultivation process influenced the level of aneuploidy. The absolute error in FISH technique was 0.13% and the relative error was 4.08%.     

The systematic approach to describing conformational rearrangements in G-quadruplexes

Conformational changes in DNA G-quadruplex (GQ)-forming regions affect genome function and, thus, compose an interesting research topic. Computer modelling may yield insight into quadruplex folding and rearrangement, particularly molecular dynamics simulations. Here, we show that specific parameters, which are distinct from those commonly used in DNA conformational analyses, must be introduced for adequate interpretation and, most importantly, convenient visual representation of the quadruplex modelling results. We report a set of parameters that comprehensively and systematically describe GQ geometry in dynamics. The parameters include those related to quartet planarity, quadruplex twist, and quartet stacking; they are used to quantitatively characterise various types of quadruplexes and rearrangements, such as quartet distortion/disruption or deviation/bulging of a single nucleotide from the quartet plane. Our approach to describing conformational changes in quadruplexes using the new parameters is exemplified by telomeric quadruplex rearrangement, and the benefits of applying this approach to analyse other structures are discussed.