Аннотация:the aggregates observed in U-937 cell line allowed identification of three types of nuclear particles dominating in these aggregates: 1) interchromatin granules of 10 x 40 nm,
2) proteasomes of 10-15 × 30 nm, 3) long perichromatin fibers. Pperichromatin fibers on sections contrasted with uranyl-acetate were seen as elongated electron dense particles 12-13 nm thick with a periodic structure with a period of 10 nm and formed by 4 nm thick helical threads PFs, suggesting presence RNA- and RNP-containing structures. We
demonstrated translocation of PFs from the nucleus to cytoplasm via nuclear pores. By application of X-ray microanalysis, we were able to detect changes in the intracellular contents of Na+ and K+ during apoptosis induced by osmotic shock. An increased ratio of intracellular Na+/K+ was detected for majority of the cells entering apoptosis.