STUDY OF MINIMAL RESIDUAL DISEASE BY MULTICOLOR FLOW CYTOMETRY IN MULTIPLE MYELOMA AFTER AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION

The frequency of achieving complete remission, as well as overall and disease-free survival, in multiple myeloma (MM) had increased due to introduction in MM treatment regimens of high-dose chemotherapy with following autologous hematopoietic stem cell transplantation (ASCT). However the number of relapses remains high, caused by persistence of residual tumor cells, i.e., the presence of minimal residual disease (MRD). One of the methods for MRD study is multicolor flow cytometry (MFC) where abnormal expression of surface antigens on myeloma plasma cells (PC) is determined. The aim of our study was to investigate the MRD by MFC before and after ASCT, the frequency of MRD-negative status achievement in complete remission (CR) patients at +100 days after ASCT and the frequency of abnormal expressed antigens on myeloma plasma cells. The study included40 MMpatients in CR at +100 days after ASCT and showed that the most common aberrations of PC were: abnormal absence of CD19 and/or CD27, decreased expression of CD38 and abnormal presence of CD56. The proportion of myeloma PCs from all bone marrow cells decreased significantly after ASCT: 20 % of patients acquired MRD-negative status, 10 % had a decrease in the number of abnormal PCs by one fold. Analysis of probability of immunochemical relapse showed that the worst prognosis was in patients with MRD-positive status before and after ASCT. During the MRD monitoring within 3-18 months, MRD-relapses were detected with the subsequent development of immunochemical relapse. The detection MRD in the dynamics is more informative than the study at only one step of therapy. It may help to select more adequate treatment for patient with multiple myeloma in each specific case

RENIN-ANGIOTENSIN SYSTEM IN REGULATION OF HEMATOPOIESIS

The renin-angiotensin system (RAS) has long been known as the endocrine system involved in the regulation of arterial pressure and waterelectrolyte balance. Local (tissue) RAS can influence cellular activity, tissue damage and regeneration. In the bone marrow there are active ligands of peptides, mediators, receptors and signaling pathways of the RAS. Local RAS can influence the growth, production, proliferation and differentiation of hematopoietic cells and participate in the regulation of both normal and pathological hematopoiesis. Angiotensin-converting enzyme (ACE) CD143 plays a key role in the classical RAS. After differentiation from hemangioblast, hematopoietic progenitor cells constantly express ACE in human embryonic, fetal and adult hematopoietic tissues, as well as at all stages of hematopoietic ontogeny. The ACE cleaves the C-terminal dipeptide and thus forms the octapeptide Angiotensin II. In addition to angiotensin II, ACE also regulates a group of biologically active peptides, such as substance P, ac-SDKP and angiotensin 1–7. Local RAS is also one of the most important components in the tumor microenvironment, affecting tumor growth and metastasis by autocrine and paracrine pathways, modulating numerous carcinogenic events such as angiogenesis, apoptosis, cell proliferation, immune responses, and extracellular matrix formation.The purpose of this review is to describe the known functions of local RAS in the hematopoiesis regulation. More detailed study of the RAS components mechanisms of action will expand therapy approaches in the neoplastic diseases and in bone marrow transplantation

Electrostatics and metal oxide wettability

The wettability of a titania surface, whose surface was partially covered with a strongly based octadecyltrihydrosilane, was studied above and below the isoelectric point (or pHiep). The advancing water contact angle is at a maximum at the pHiep, decreasing symmetrically on either side in a Lippmann-like manner. The change in wettability, for a given pH, became more pronounced with increasing salt concentration. Using a non-Nernstian model of the electrical double layer, the experimental dependence of contact angle on both pH and salt concentration was satisfactorily predicted