[Melting profiles for lymphocyte chromatin of healthy subjects and Down's disease patients obtained by the technic of cellular DNA absorption in ultraviolet light].

Integral values of optical density (E260) were obtained for lymphocyte nuclei from normal people and those suffering from Down's syndrome during the melting of cells in media of varying ionic strength (0.15 M NaCl - control; 0.015, 0.0015 and 0.00015 M NaCl - experimental). The differences in E260 were obtained only during the melting of cells in 0.15 M NaCl. In lymphocytes from normal people, the distinctly reproducible hyperchromic effect was detected from 78 degrees (up to 35--40%), reaching the plateau by 96 degrees C (P less than 0.01). In identical conditions, the hyperchronic effect on aneuploid cells was revealed only after 98 degrees C (P less than 0.01). The data presented confirm the authors' concept of the greater condensation of aneuploidic genome.