Localization of adenosine deaminase and adenosine deaminase complexing protein in rabbit brain.

Abstract

Brains fixed in paraformaldehyde or in Clarke's solution were blocked coronaily. Blocks from brains fixed in paraformaldehyde were either frozen in liquid nitrogen or embedded in paraffin. Tissue fixed in Clarke's solution was embedded in paraffin. Sections from each block were stained by the peroxidase-antiperoxidase method for adenosine deaminase or complexing protein using affinity-purified goat antibodies. Adenosine deaminase and complexing protein did not co-localize. Adenosine deaminase was detected in oligodendroglia and in endotheial cells lining blood vessels, whereas complexing protein was concentrated in neurons. The subcellular location and appearance of the peroxidase reaction product associated with individual cells was also quite distinctive. The cell bodies ofadenosine deaminase-positive oligodendroglia were filled with intense deposits ofperoxidase reaction product. In contrast to oligodendroglia, the reaction product as-If the regulatory actions of adenosine depend on binding to cell surface receptors, it seems reasonable that the concentration ofextracellular adenosine should also be subject to regulation. Wu and Phillis (1984) have suggested that uptake and metabolism of

Endothelial catabolism of extracellular adenosine during hypoxia: the role of surface adenosine deaminase and CD26

“…Significant evidence suggests that surface ADA activity can be associated with the dipeptidyl peptidase CD26. 29 Here, we considered the possibility that expression of CD26 may parallel the ADA induction profile observed in hypoxia. To do this, we assessed CD26 expression in HMEC-1s and HUVECs following exposure to hypoxia.…”

Immunohistochemical Demonstration of Adenosine Deaminase (ADA1) in Human Tissues

“…The histochemical localization of ADA has been investigated in various tissues and species [4,5,6,22,26]. However, the immunohistochemical localization of ADA in human tissues has not been extensively investigated, except for a few studies of hematopoietic and lymphatic systems [4,5].…”

“…As for tissues, immunohistochemical localization of ADA studies have been performed extensively using tissues from the brain [13,22] and digestive tract [7,25]. However, immunohistochemical localization of ADA has not been performed with human tissues, except for the thymus [4].…”

Investigation of the Mechanism of Enhancement of Central Nervous System Delivery of 2′-β-Fluoro-2′,3′-Dideoxyinosine Via a Blood-Brain Barrier Adenosine Deaminase-Activated Prodrug

“…Furthermore, the steady-state brain parenchyma/plasma concentration ratio of F-ddI was found to be 5-fold higher than that obtained after an equivalent F-ddI infusion, suggesting that F-ddA was indeed acting as an ADA-activated prodrug of F-ddI. Although substantial levels of ADA exist in the brain tissue, with particularly high activities in endothelial cells of the BBB (Nagy et al, 1984;Mistry and Drummond, 1986;Schrader et al, 1987;Johnson and Anderson, 1996), the site of prodrug activation remains unclear. The present study was undertaken to clarify the role of the BBB in the bioconversion of F-ddA during its passage across the BBB, using uptake studies into primary cultured bovine brain microvessel endothelial cells (BBMECs).…”