No abstract

No abstract

Endothelial cells are known to participate in angiogenesis, adaptation of vascular tonus and maintenance of blood fluidity in the microcirculation. To investigate these functions in the placenta, we devised a method of isolation and culture of endothelial cells from villous microvessels. In primary culture, these intraplacental endothelial cells exhibited many features observed in microvascular endothelium from other organs: spindle-shape, rosette associations, circular arrangements and confluence. In contrast to the confluent endothelial cells derived from the umbilical vein, cells from microvessels did not form a cobblestone network. After trypsin digestion of microvessels, magnetic microbeads coated with S-Endol immunoglobulin, antithrombomodulin and Ulex europaeus-I lectins were tested for sorting endothelial cells. Only the microbeads coated with antithrombomodulin allowed a suitable magnetic cell separation after trypsinization. By contrast, the microbeads coated with each of these antibodies or with lectins attached to confluent cells from the second passage. The microbeads detached from the cells at different rates. Their examination by scanning microscopy indicates that a portion of these microbeads was phagocytosed. Microvascular endothelial cells from the second passage were intensively stained by the anti-von Willebrand reaction and only weakly by the anti-smooth muscle alpha-actin reaction. They incorporated acetylated-low density lipoproteins coupled to a fluorescent probe. The positive reactions against the anti-von Willebrand factor and the uptake of the fluorescent acetylated-low density lipoproteins were modified after eight passages.

No abstract

An immunocytochemical and ultrastructural study using the Fab fragment of an anti-human Ig antibody labelled with peroxidase was carried out on affected lymph nodes from five Hodgkin's disease patients. The tumor cells (Reed-Sternberg cells and Hodgkin cells) showed an exclusively hyaloplasmic granular staining. By comparing these grains with ribisome staining. By comparing these grains with ribosome staining of the endoplasmic reticulum of plasma cells it could be suggested that they are free risobomes. This ribosomal Ig synthesis is a major argument for the B lymphocyte nature of Reed-Sternberg and Hodgkin cells. The total absence of vacuole staining allows us to conclude that these cells are not histiocytic or macrophage derivatives.