[Ultrastructure of nuclear membrane pockets in lymphoid cells in cattle].

In comparison with the cells of lymphoreticular tissue in a normal lymph node, the lymphoid cells of a tumorous lymph node in cattle suffering from lymphatic leucaemia show a high occurrence of nuclear pockets. The pockets protrude above the nucleus surface and contain cytoplasmic particles. The wall of a nuclear pocket on the outer side of the nucleus consists of two complete nuclear membranes with an inter-layer of highly condensed heterochromatin. The structure of the nuclear pocket wall documents the origin of the pockets from secondary connection of the plicae of the nuclear membrane and enclosing of part of cytoplasm in the pocket.