Immunogold study of effects of prenatal exposure to lipopolysaccharide and/or valproic acid on the rat blood-brain barrier vessels.

The involvement of blood microvessels, representing the anatomic site of the blood-brain barrier (BBB), in brain damage induced by prenatal exposure to lipopolysaccharide (LPS) and/or valproic acid (VPA) was studied in four-week-old rats. The immunogold procedure was applied for localization at the ultrastructural level of endogenous albumin and glucose transporter (GLUT-1) in three brain regions: cerebral cortex, cerebellum and hippocampus. Four groups of rats were used: (1) untreated control, (2) prenatally VPA-treated, (3) prenatally LPS-treated, and (4) prenatally LPS- and VPA-treated.

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.

Immunogold study of interendothelial junction-associated and glucose transporter proteins during postnatal maturation of the mouse blood-brain barrier.

The distribution of glucose transporter (GLUT-1) and of interendothelial junction-associated proteins--zonula occludens protein (ZO-1), occludin, and beta-catenin--was studied using quantitative immunogold procedure. Lowicryl K4M-embedded samples of the cerebral cortex of 1-, 7-, and 14-day-, and 6-week-old (young-adult) mice were used. Ultrathin sections were exposed to specific rabbit polyclonal antibodies followed by colloidal gold-labelled secondary antibodies.

Cytochemical study of the involvement of cell organelles in formation and accumulation of fibrillar amyloid in the pancreas of NORbeta transgenic mice.

Phosphatase ultrastructural cytochemistry was used to evaluate the participation of cytoplasmic organelles in the accumulation of fibrillar amyloid beta (Abeta) in exocrine acinar cells and in macrophages of the pancreas of transgenic mice overexpressing a carboxy-terminal fragment of Abeta protein precursor (ABPP). Nucleoside diphosphatase (NDPase) and glucose-6-phosphatase (G6Pase) were used as cytochemical markers of the endoplasmic reticulum (ER), thiamine pyrophosphatase (TPPase) as a marker of the Golgi apparatus (GA), and acid phosphatase (AcPase) as a marker of lysosomes. Monoclonal antibody 4G8 raised against the 17-24 aa sequence of human Abeta protein was used for immunogold localization of fibrillar Abeta.

Quantitative immunogold study of glucose transporter (GLUT-1) in five brain regions of scrapie-infected mice showing obesity and reduced glucose tolerance.

Distribution of glucose transporter (GLUT-1) in the microvascular endothelium of scrapie-infected SJL/J hyperglycemic mice showing clinical signs of scrapie, obesity and reduced glucose tolerance was studied in five brain regions: cerebral cortex, hippocampus, thalamus, cerebellum and olfactory bulb. Uninfected normoglycemic SJL/J mice showing normal glucose tolerance were used as a control. Ultrathin sections of brain samples embedded at low temperature in the hydrophilic resin Lowicryl K4M were exposed to anti-GLUT-1 antiserum followed by gold-labeled secondary antibodies.

Effect of a single embryonic exposure to alcohol on glucose transporter (GLUT-1) distribution in brain vessels of aged mouse.

Distribution of glucose transporter (GLUT-1) in brain microvascular endothelium, representing the anatomic site of the blood-brain barrier (BBB), was studied with electron microscopy in 24-month-old mice, which had been exposed prenatally (on 9th day of gestation) to a single teratogenic dose of ethanol. Offspring of mice that had received an equivalent volume of isocaloric dextrose served as controls. Sections of brain samples embedded at low temperature in hydrophilic resin Lowicryl K4M were exposed to anti-GLUT-1 antiserum followed by gold-labelled secondary antibodies.

Immunogold study of regional differences in the distribution of glucose transporter (GLUT-1) in mouse brain associated with physiological and accelerated aging and scrapie infection.

Distribution of glucose transporter (GLUT-1) in brain microvascular endothelia, representing the anatomic site of the blood-brain barrier (BBB), was studied in adult, physiologically aged, senescence-accelerated prone (SAMP8) and in scrapie-infected mice. Sections of tissue samples obtained from four brain regions (cerebral cortex, hippocampus, cerebellum, and olfactory bulb) and embedded in Lowicryl K4M were exposed to anti-GLUT-1 antiserum followed by gold-labeled secondary antibody. Labelling density was recorded over luminal and abluminal plasma membranes of the microvascular endothelial cells.

Increased blood-brain barrier permeability and endothelial abnormalities induced by vascular endothelial growth factor.

The early effects of intracerebrally infused vascular endothelial growth factor (VEGF) on the blood-brain barrier (BBB) to endogenous albumin were studied using a quantitative immunocytochemical procedure. In addition, transmission electron microscopy was used to observe morphological changes induced in brain vasculature. A solution of VEGF in saline (40 ng/10 microliters) was infused into the parieto-occipital cortex of mice, which were killed 10 min, 30 min, and 24 h afterwards.

Quantitative immunocytochemical study of blood-brain barrier glucose transporter (GLUT-1) in four regions of mouse brain.

Application of immunogold cytochemistry revealed polar (asymmetric) distribution of GLUT-1 in mouse brain microvascular endothelia, representing the anatomic site of the blood-brain barrier (BBB). This polarity was manifested by an approximately threefold higher immunolabeling density of the abluminal than the luminal plasma membrane of the endothelial cells. The immunoreaction for GLUT-1 in nonbarrier continuous (skeletal muscle) or fenestrated (brain circumventricular organs) microvascular endothelial cells was absent.

Interaction of glycated albumin-gold complexes with mouse brain microvascular endothelium.

The main objective of this study was to obtain new information about the structural aspects of the enhanced brain uptake of blood-borne glycated albumin observed recently by authors using quantitative, biochemical methodology. Bovine serum albumin glycated in vitro by progressive accumulation of advanced glycosylation end products complexed with colloidal gold (AGE-BSA-G) was used. Mice received a bolus injection of this complex into the common carotid artery and were killed after 3, 15, and 30 minutes.

Ultrastructural study of the clearance of intracerebrally infused native and modified albumin-gold complexes.

The main objective of this ultrastructural study was to gain a better understanding of the involvement of brain vasculature in clearance of proteins from edematous fluid. For this purpose, both native and modified (cationized, glucosylated, and mannosylated) bovine serum albumin-gold complexes (BSA-G, catBSA-G, glucBSA-G and manBSA-G respectively) dissolved in phosphate-buffered saline (PBS) were infused (10 microliters) into mouse cerebral cortex. Samples of brain were taken at 30 min, 1 h, and 24 h post-infusion for electron microscopical examination.

Immunocytochemical evaluation of blood-brain barrier to endogenous albumin in scrapie-infected mice.

A quantitative immunocytochemical procedure was used for evaluation of the blood-brain barrier (BBB) to endogenous albumin in plaque-forming (PF) and non-plaque-forming (NPF) groups of scrapie-infected mice at the clinical stage of disease. Ultrathin sections of brain samples (cerebral cortex, hippocampus and cerebellum) embedded in resin (Lowicryl K4M) were exposed to anti-mouse albumin antiserum followed by protein A-gold. Using morphometry, the density of immunosignals (gold particles per microns2) was recorded over four compartments: vascular lumen, endothelium, subendothelial space, and brain parenchyma (neuropil).

Ultrastructural study on the interaction of native and cationized albumin-gold complexes with mouse brain microvascular endothelium.

The main objective of this ultrastructural study was to gain insights into the cellular mechanisms responsible for the enhanced brain uptake of blood-borne cationized albumin observed by several authors utilizing quantitative methodology. Mice were injected intravenously or into the common carotid artery (in vivo experiments) or perfused in situ with solutions of native or cationized bovine serum albumin complexed with colloidal gold (BSA-G or cBSA-G respectively). The results indicate that: (1) the main drawbacks of in vivo experiments are very intense phagocytosis of the tracer particles by Kupffer cells located in the liver sinusoids and also escape of the tracer through capillaries of skeletal and heart muscles.

Immunocytochemical evaluation of the blood-brain barrier to endogenous albumin in the olfactory bulb and pons of senescence-accelerated mice (SAM).

The blood-brain barrier (BBB) to endogenous albumin was studied in the olfactory bulb and pons of the senescence-accelerated prone (SAMP8) mouse and senescence-accelerated resistant (SAMR1) mouse strains by using a quantitative immunocytochemical procedure. Ultrathin sections of Lowicryl K4M-embedded samples were exposed to anti-mouse albumin antiserum followed by protein A-gold. Morphometric analysis of the electron micrographs revealed that in the olfactory bulb of both groups of animals, especially in the internal granular layer, some percentage of capillaries and slightly larger microvessels showed leakage of albumin.

A quantitative immunocytochemical study of blood-brain barrier to endogenous albumin in cerebral cortex and hippocampus of senescence-accelerated mice (SAM).

The blood-brain barrier (BBB) to endogenous albumin was studied in the cerebral cortex and hippocampus of the senescence-accelerated prone (SAMP8) mouse and senescence-accelerated resistant (SAMR1) mouse strains in corresponding age groups by using a quantitative immunocytochemical procedure. Brain samples after immersion-fixation were embedded at low temperature in Lowicryl K4M and sectioned with an ultramicrotome. Thin sections were exposed to anti-mouse albumin antiserum followed by protein A-gold.

Immunocytochemical studies of protamine-induced blood-brain barrier opening to endogenous albumin.

The cellular mechanisms of blood-brain barrier (BBB) opening to endogenous albumin in the mouse brain after intracarotid infusion of solutions of protamine free base (PB) or protamine sulfate (PS) were studied using quantitative immunocytochemistry. Ultrathin sections of brain samples embedded at low temperature in Lowicryl K4M were exposed to anti-mouse albumin antiserum followed by protein A-gold. Using morphometry, the density of immunosignals (gold particles per micron2) was recorded over four compartments: vascular lumen, endothelial profiles, subendothelial space (including the basement membrane), and brain parenchyma (neuropil).

A quantitative immunocytochemical study of the osmotic opening of the blood-brain barrier to endogenous albumin.

The time sequence of the blood-brain barrier opening to endogenous albumin in rat brain after intracarotid infusion of hyperosmolar L(+)arabinose was studied using quantitative immunocytochemistry. Brain samples obtained 1, 5, and 30 min after insult were immersion-fixed in formaldehyde-glutaraldehyde mixture and embedded at low temperature in Lowicryl K4M. Untreated rats or rats exposed only to Ringer's solution were used as a control.

Ultrastructural study on the interaction of insulin-albumin-gold complex with mouse brain microvascular endothelial cells.

The interaction between the brain microvascular endothelium and bovine serum albumin complexed with insulin and colloidal gold (insulin-BSA-gold) was studied in adult and newborn mice. The results suggest: (a) the modification of albumin enhances its binding to the luminal front of the endothelial cells, as compared to unmodified albumin used in previous studies from this laboratory; (b) the binding density of insulin-BSA-gold complex to blood-brain barrier microvessels is approximately 2.5 times higher in newborn than in adult mice; (c) in adult mice, fenestrated endothelia of the median eminence and choroid plexus demonstrate the highest binding capacity (over five and two times higher, respectively, than in blood-brain barrier endothelia); (d) in the median eminence only, the gold-labelled tracer particles may be transported across the vessel wall.

Ultracytochemical studies of the effects of aluminum on the blood-brain barrier of mice.

We studied the effect of chronic exposure (6 weeks and 6 months) of mice to drinking (tap) water containing 1.76% (0.06 M) aluminum lactate on some cytochemical properties of the blood-brain barrier (BBB).

Cytochemical study of the effect of aluminium on cultured brain microvascular endothelial cells.

The cytotoxic effect of aluminium was studied on cultured goat brain microvascular endothelial cells used as an in vitro model of the blood-brain barrier. Confluent monolayers of these cells were exposed for 4 days to aluminium maltol and, for control purposes, to maltol alone, and also to cadmium chloride as a known cytotoxic substance. The localization of plasmalemma-bound enzymatic activities of 5'-nucleotidase and Ca(2+)-ATPase and the distribution of sialic acid residues were studied at the ultrastructural level.

Immunocytochemical evaluation of blood-brain barrier to endogenous albumin in adult, newborn and aged mice.

The blood-brain barrier (BBB) to endogenous albumin was studied in normal adult, newborn and aged mice by using quantitative immunocytochemical procedures. For control purposes, the non-BBB-type of microvasculature from skeletal muscle (diaphragm) was also examined. Thin sections of tissue samples embedded at low temperature in hydrophilic resin Lowicryl K4M were exposed to anti-mouse albumin antiserum followed by protein A-gold.