A simple procedure for in situ immunolabeling, embedding and sectioning of layers of cultured endothelial and smooth muscle cells for both light and electron microscopy.

We present a simple procedure for in situ immunolabeling, embedding and sectioning of layers of cultured endothelial and smooth muscle cells for both light and electron microscopy. Endothelial and smooth muscle cells were seeded in tissue culture chambers/slides precoated with 30% (w/v) gelatin drops fixed with 0.5% glutaraldehyde. Live endothelial cell layers were labeled with an antibody against the surface membrane protein, anti-CD13. After labeling, the cell layers were fixed and separated from the chambers/slides by lifting all of the samples with a spatula. Sections (1-2 mm) were cut, embedded and processed further for light or electron microscopy. Because of the delicate cell layers and the importance of preserving maximum integrity, labeling was performed under standard culture conditions and treated in situ during the entire procedure. Moreover, the small chamber size of the tissue culture dishes generated the additional advantages of requiring only a limited number of cells, small volumes of media, and little antibody.

Myelodysplasia following paroxysmal nocturnal haemoglobinuria: evidence for the emergence of a separate clone.

A patient with paroxysmal nocturnal haemoglobinuria (PNH) who developed a myelodysplastic syndrome (MDS) is described. After the onset of myelodysplasia the neutrophils of the patient fully expressed GPI-linked proteins. It is concluded that the myelodysplasia does not originate from transformed PNH stem cells, but represents the emergence of a separate clone arising from an injured marrow.