THE STRUCTURAL AND FUNCTIONAL STATE OF RED CELLS MEMBRANES IN CHILDREN WITH ACQUIRED APLASTIC ANEMIAS AND MYELODYSPLASTIC SYNDROME EXPOSED TO THE ACTION OF LOW-DOSES RADIATION. 154

Abstract

From 1986 to 1996 53 children (age 1-15 years old) with acquired aplastic anemia (AAA) and myelodysplastic syndrome were followed. All children lived in the regions with chronic action of low doses radiation. The biophysical indexes of erythrocyte membranes (microviscosity of lipid bilayer (MLB), osmotic and thermostability, Mt-Hb level, daily hemolysis (DH), RBC lifespan) were investigated. It had been shown that red cells of children with AAA and MDS obtained improved osmotic resistance. There are some differences between kinetic values of red cell's thermohemolysis in children with AAA and MDS. The decrease of thermoresistance of red cell membrane in patient with AAA and MDS could be explained by changes in Hb values. In comparison with control group average level of Mt-Hb in red cells was elevated by 5-10%. Besides, the descrease of red cell thermoresistancy was associated with the disturbances of lipid-lipid interaction in membranes. It was revealed that kinetic values of membrane acetylcholinesterase were low in children with AAA and had no significant differences in children with MDS. There was an increase of MLB in red cell membrane in patients with AAA and no changes of the latter in patients with MDS. Kinetics of red cell revealed intensification of DH and short-term RBC lifespan in patients with AAA and MDS. Our data showed that red cell membranes are sensitive markers and take part in pathogenesis of AAA and MDS.