[Ultrastructure of the lymphocytic nucleus under the effect of phytohemagglutinin stimulation].

The author presents a review of the literature, in which he describes the blast transformation of lymphocytes, induced by lectines, as a proper model for examining the metabolic and connected with them morphological changes in cellular activation. The literature connected with the basic achievements in examining the ultrastructure of the interphase nucleus is also described. The author presents his studies on the dynamic changes, occuring in the nucleus in the course of the blast transformation, induced by phytohemagglutinin. The author found early changes in the nuclear chromatin, discovered within the first hour, using together with the ordinary double staining and the method for visualization of RNA structures (EDTA method of W. Bernar) and the method of G. Moyne for establishing DNA. It was established by means of nuclear morphometry that within the first hour the reduction of dense chromatin on account of the dispersed chromatin was 7,7%, the 24th hour was 26,0% and on the 48th hour was 26,3%. On the basis of the morphometric examination the author found also that the largest was the number of perichromatin granules in nontransformed lymphocytes of PHA-cultures. The supposition that these were B-lymphocytes was supported by analogous morphometric examination on lymphocytes obtained from the thymus and bursa Fabricius of newly shelled chickens and it was established that this number in the bursa was more than twice larger. There were three types of arrangement of the interchromatin granules: in groups, diffuse and in chains and it was found that the last type was connected with the largest number of perichromatin granules. The author discusses the possibility for a transfer of whole perichromatin granules through the nuclear pores in cases under strong stimulation such as that of phytohemagglutinin.