[Morphometric and densitometric studies on the ultrastructure of endothelial cells in capillaries in tumor bearing rats].

The permeability of tumor capillaries to higher molecular substances like albumin and beta-globulin is increased. The comparison of permeability is associated with a modification of the ultrastructure of the capillary wall, especially of endothelial cells and their nuclei. On micrographs of blood capillaries Zajdela-Ascites-Hepatoma pregnanted rats we've studied a) morphometrically the surface and the volume of endothelial cell nuclei in relation to the time after tumor implantation, b) densitometrically the Hetero-Euchromatin-ratio in the nuclei of the same cells in relation to tumor time too. We've got the following results: The surface of the endothelial cell nuclei is increasing in the first four days, then it's decreasing to the 8th day. The volume of the same nuclei is increasing to the 4th experimental day too, then it's relatively steady. At the 6th experimental day the largest part of Heterochromatin is "euchromatinized". It will be possible to distinguish the functionally and the degeneratively nucleus' swelling with morphometrically methods. The reasons of modifications in the ultrastructure of blood capillary endothelial cell nuclei might be a) the increased demandings to the permeability of capillary wall, b) the increased activity of the MMS/RHS and c) local immunity reactions against the tumor.