Diagnosis of Acute Lymphoblastic Leukemia Originating From T-Lineage Precursors and Approaches to Minimal Residual Disease Monitoring

Background. Minimal residual disease (MRD) is an independent prognostic factor in acute lymphoblastic leukemia (ALL) in children. The immunological assessment of MRD cell count is based on aberrant immunophenotype of tumor lymphoblasts. However, in the case of ALL originating from T-lineage precursor cells (T-ALL) no clear aberrancy criteria have been defined, yet. Flow-cytometric MRD assessment in T-ALL can be based on characteristics of normal T-cell ontogenesis, i.e. the absence of normal T-lineage precursor cells (T-LP) in bone marrow. Aim. To assess the feasibility of immunological method of flow cytometry for MRD detection based on T-LP immunophenotype on Days 15 and 33 of treatment of T-ALL children. Materials & Methods. The analysis included the data on primary immunophenotype and MRD assessment on Dayы 15 and 33 of treatment of 31 T-ALL patients in the age of 2–17 years. In the majority of cases (61.3 %) the cortical/thymic immuno-subvariant of ALL was detected, in the rest of cases (38.7 %) it was the pre-T-cell one. Diagnosis was based on cumulative results of morphocytochemical and immunological bone marrow analyses. Assessing the MRD state the morphological and immunological analyses of bone marrow aspirate were carried out in parallel with one and the same tube. All patients enrolled in the trial were treated at Scientific Research Institute of Pediatric Oncology and Hematology of NN Blokhin National Medical Cancer Research Center according to the ALL IC-BFM 2009 protocol. Results. Our study demonstrated that at all therapy stages MRD can be assessed by the unified immunological method based on detecting cyCD3+CD7+/++smCD3– (T-LP) immunophenotype cells. It is important to ensure that the correct clones of monoclonal antibodies are used for detecting CD3 cytoplasmic and membrane molecules (UCHT1 and SK7, respectively). Standard risk group included no patients. The majority of patients (76.2 %) treated according to ALL IC-BFM 2009 protocol were assigned to medium risk group on Day 15 of treatment. By Day 33 a quarter of them (25 %) was included into high risk group. Conclusion. The capabilities of multicolor flow cytometry allow for the most complete characterization of primary immunophenotype of tumor T-cell lymphoblasts for further search of leukemia-associated immunophenotypes. Specific ontogenesis features of normal T-cells enable unification of immunological approaches to MRD assessment at all stages of T-ALL therapy

Magnetization of crystalline and amorphous phases of R2Ti2O7 and R2Zr2O7 (R= Gd, Dy, Tb)

We present the study of frustrated magnets R2M2O7, where R = Gd, Dy, Tb and M = Ti, Zr. Magnetic susceptibility χ and low-temperature magnetization of perfectly ordered pyrochlores R2Ti2O7, partially disordered fluorites R2Zr2O7, and their completely disordered amorphous phases were measured and analyzed. We have found that structural disorder weakens the exchange interaction of the rare-earth ions. Magnetic moments of dysprosium and terbium, obtained from nearly saturated magnetization, are slightly affected by the disorder while the gadolinium moment is completely independent of it. The local structure of the compounds, including oxygen environment of the rare-earth ions, is discussed in terms of the influence of the crystal electric field on the magnetic properties of R2M2O7

Kinetics and Mechanisms of the Oxidation of Gaseous Sulfur Compounds

The problems associated with global climate change in general, and acid rain in particular, have led to a great deal of research on the atmospheric and combustion chemistry of sulfur. Developments over the last decade have led to significant progress in our understanding of the kinetics and mechanisms of the atmospheric oxidation chemistry of natural and anthropogenic sulfur. Rather less effort, however, has been placed on developing an understanding of sulfur combustion kinetics; the emphasis of mitigation research has instead been placed on removal of sulfur from fuels or development of scrubbing techniques to remove SO2 from stack gases