Comparative lectinhistochemical studies on paraffin- and glycol methacrylate-embedded CNS tissue specimens from AIDS autopsies. Mistletoe lectin I (ML I) as cell-marker.

Brain tissue and spinal cord tissue from 12 patients who had died of AIDS was fixed in neutral formalin; then after the embedment of some of it in paraffin and some of it in glycol methacrylate, it was analyzed lectinhistochemically with mistletoe lectin I (ML I). Mistletoe lectin (ML I) is a reliable marker for microglia cells and macrophages and for special cell forms (polynuclear giant cells, so-called pericytes) belonging to this cell system. In both the embedding procedures used, the representation of the cells is very clear and subtly differentiated so that the preparations are very well suited to the study of AIDS-associated tissue damage in the CNS. Whereas the immunological macrophage markers (CD 68 markers) KPI, PG-M1 produce good results on paraffin-embedded material but are completely useless on material embedded in glycol methacrylate, the cells of the monocyte-macrophage system can be represented very well and reliably after being embedded in glycol methacrylate with mistletoe lectin I (ML I).

[Immunohistochemical demonstration of the proliferation zone of the gastric mucosa]. / Zur immunhistochemischen Darstellung der Proliferationszone der Magen-schleimhaut.

The area of proliferation in the mucosa of the gastric antrum and fundus was demonstrated immunohistochemically in an unselected sample of biopsy material using the monoclonal antibody Ki 67. The findings in normal noninflamed preparations were compared with preparations of chronic superficial gastritis and a small group of advanced, partially atrophic gastritis. In all preparations the site of the proliferation was typically in the neck of the gastric glands and in the lower area of the gastric pits. However, in the fundus these areas were much narrower than in the antrum. Only isolated positively labelled cells were found outside the proliferation zone in the specific gland body and in the upper part of the gastric pits near the surface of the mucosa. There was a distinct increase of the breadth of the proliferation zone and the labelling index in chronic inflammatory processes. However, pronounced spreading or displacement of the proliferative cell population to the surface was not shown. In all preparations the areas of proliferation contained both positively labelled cells within the cell cycle and varying numbers of nonlabelled nuclei, which may be considered to be a resting reserve population.