Evaluating the role of substance P in the growth of brain tumors

Abstract not availableE. Harford-Wright, K. M. Lewis, R. Vink and M. N. Ghabrie

Distribution of a putative endothelial barrier antigen in the ocular and orbital tissues of the rat.

BACKGROUND--A rat endothelial barrier antigen (EBA) recognised by a monoclonal antibody has been shown to be expressed strongly by endothelial cells of brain capillaries possessing a blood-brain barrier and only weakly expressed by fenestrated brain vessels. METHODS--In this study immunocytochemical methods for light and electron microscopy were used to study EBA distribution in the eye and orbital tissues of the rat. RESULTS--Blood-ocular barrier vessels in the optic nerve, retina, iris, and some vessels in th choroid and ciliary body were immunopositive for EBA. By pre-embedding immunocytochemistry for electron microscopy the antigen was observed on the luminal endothelial cell surface. CONCLUSION--Surprisingly, some non-barrier vessels in the ciliary body and choroid expressed EBA suggesting that it may play a broader role in endothelial properties than previously recognised. The functional significance of EBA remains to be elucidated

Clostridium perfringens prototoxin-induced alteration of endothelial barrier antigen (EBA) immunoreactivity at the blood-brain barrier (BBB)

Copyright © 2001 Academic Press. All rights reserved.It has been reported that the severe cerebral edema produced in experimental animals by Clostridium perfringens (Cl p) type D toxin can be prevented by prior treatment with its precursor prototoxin due to competitive binding to endothelial cells (ECs) at the blood–brain barrier (BBB). In this study we investigate the effects of the prototoxin on the BBB, without added toxin. The integrity of the BBB was assessed by its ability to prevent leakage of endogenous albumin. ECs at the BBB were studied by immunocytochemistry for any alteration in the endothelial barrier antigen (EBA), a molecular marker for the intact BBB. Immunocytochemistry showed rapid but mild opening of the BBB to endogenous albumin. Light and electron immunocytochemistry showed qualitative and quantitative reduction in EBA immunoreactivity, with a spectrum of changes at time intervals from 1 h to 14 days post-prototoxin injection. Some vessels with ultrastructural changes and widening of the perivascular space retained EBA immunoreactivity. Many vessels showed partial or complete loss of EBA staining with minimal widening of the perivascular space and edema. Recovery of EBA expression was still incomplete at 14 days postinjection. This is the first report to show endothelial cell damage, mild reversible cerebral edema, and alteration in BBB markers following administration of Cl p prototoxin. This model of mild brain edema may be useful for BBB studies.C. Zhu, Mounir N. Ghabriel, P. C. Blumbergs, P. L. Reilly, J. Manavis, J. Youssef, S. Hatami and J. W. Finniehttp://www.elsevier.com/wps/find/journaldescription.cws_home/622828/description#descriptio