Increased expression of beta-catenin in brain microvessels of a segmentally trisomic (Ts65Dn) mouse model of Down syndrome.

We examined the distribution of beta-catenin and endogenous blood serum albumin at the ultrastructural level in blood microvessels (capillaries) from brains of control and trisomic Ts65Dn mice. Morphological examination revealed an increased immunolabeling for beta-catenin in endothelial substructures of the capillary network, such as intercellular junctions, cytoplasm, and nuclei. These immunosignals were significantly increased in all endothelial substructures from trisomic mice.

Quantitative immunogold study of increased expression of metallothionein-I/II in the brain perivascular areas of diabetic scrapie-infected mice.

Quantitative immunogold procedure was used to study the distribution of metallothionein I/II (MT-I/II) at the ultrastructural level in the perivascular areas, including microvascular endothelial cells (ECs) and astrocytes with their perivascular end-feet, in brains of scrapie-infected hyperglycemic (diabetic) and normoglycemic (non-diabetic) mice. Samples of the fronto-parietal cortex obtained from diabetic and non-diabetic scrapie-infected, as well as from non-infected (control) SJL/J mice, were processed for immunocytochemical examination. In control mice, the labelling of the ECs was of low intensity, restricted to few immunogold particles in the cytoplasm.

Immunogold study of altered expression of some interendothelial junctional molecules in the brain blood microvessels of diabetic scrapie-infected mice.

Quantitative immunogold procedure was used to study the distribution of molecular components of interendothelial junctions in blood-brain barrier (BBB) microvessels of scrapie infected SJL/J hyperglycemic mice showing obesity and reduced glucose tolerance. Samples of brain (fronto-parietal cerebral cortex and thalamo-hypothalamic region) obtained from hyperglycemic (diabetic) mice and from non- infected, normoglycemic (non-diabetic) SJL/J mice, were processed for immunocytochemical examination. The localization of the following tight junction (TJ)-associated proteins was studied: occludin as an integral membrane (transmembrane) protein, and zonula occludens one (ZO-1) as a peripheral protein.

Immunogold localization of tight junctional proteins in normal and osmotically-affected rat blood-brain barrier.

The distribution of molecular components of interendothelial tight junctions (TJs) was studied in rat blood-brain barrier (BBB) microvessels, using immunogold cytochemistry applied to electron microscopy. Samples of rat brains, both normal (unaffected) and osmotically-affected (1, 5, and 30 min after intracarotid infusion of 1.8 M L(+)arabinose), were processed for immunocytochemical localization of TJ-specific integral membrane (occludin, JAM-1, claudin-5) and peripheral (ZO-1) protein molecules.

Molecular anatomy of interendothelial junctions in human blood-brain barrier microvessels.

Immunogold cytochemical procedure was used to study the localization at the ultrastructural level of interendothelial junction-associated protein molecules in the human brain blood microvessels, representing the anatomic site of the blood-brain barrier (BBB). Ultrathin sections of Lowicryl K4M-embedded biopsy specimens of human cerebral cortex obtained during surgical procedures were exposed to specific antibodies, followed by colloidal gold-labeled secondary antibodies. All tight junction-specific integral membrane (transmembrane) proteins--occludin, junctional adhesion molecule (JAM-1), and claudin-5--as well as peripheral zonula occludens protein (ZO-1) were highly expressed.

Molecular anatomy of intercellular junctions in brain endothelial and epithelial barriers: electron microscopist's view.

In this review, we have tried to summarize the current knowledge on the distribution of important molecular components of intercellular junctions-both tight junctions (TJs) and adherens junctions (AJs)-at the level of ultrastructure. For this purpose, immunogold procedure was applied to ultrathin sections of brain samples obtained from mice, rats, and humans and embedded in hydrophilic resin Lowicryl K4M. The results of our observations performed with transmission electron microscopy (EM) are discussed and compared with findings of other authors.