LECTIN BINDING IN MENINGIOMAS

Forty-two meningiomas of different morphological sub-type were examined to determine their pattern of binding to 11 different lectins which characterize cell surface components such as carbohydrate residues. Histiocytic and xanthoma cells within meningiomas could be demonstrated with six different lectins: wheat germ agglutinin (WGA), peanut agglutinin (PNA) Bauhinia purpurea agglutinin (BPA), Helix pomatia agglutinin (HPA), Vicia fava agglutinin (VFA) and Soyabean agglutinin (SBA). Vascular elements including endothelial cells and intimal cells, bound Ulex europaeus agglutinin type 1 (UEA 1), WGA and HPA. The fibrous stroma in fibrous and fibroblastic meningiomas bound PNA, Laburnum alpinum agglutinin (LAA) and SBA. Tumour cells in meningotheliomatous meningiomas and some areas of anaplastic meningiomas bound Concanavalin A, PNA, LAA and VFA whereas tumour cells in fibrous and fibroblastic meningiomas bound BPA, LAA and VFA. Lectin binding has proved to be of value in detecting histiocytic and xanthoma cells together with vascular elements within meningiomas. In addition, the different lectin binding patterns allow different histological sub-types of meningioma to be distinguished although the biological significance of the binding patterns is unclear.     

Selective lectin binding of the developing mouse retina

A battery of eight lectins with different carbohydrate specificities was used to study changes in glycoconjugate expression during cell differentiation in the mouse retina. The lectins tested included concanavalin A (Con A), wheat germ agglutinin (WGA), soybean agglutinin (SBA), peanut agglutinin (PNA), Ulex europaeus agglutinin (UEA), Ricinus communis agglutinin I (RCA), Dolichos biflorus agglutinin (DBA), and Limulus polyphemus agglutinin (LPA). Unfixed frozen sections of adult and early postnatal mouse retina were treated with fluorescein isothiocyanate-conjugated lectins and examined by fluorescence microscopy. The results showed selective lectin binding in both cellular and synaptic retinal layers of the adult mouse and throughout postnatal development. In general, an increase in intensity of fluorescent lectin staining during retinal development was observed for Con A, WGA, DBA, LPA, RCA, and PNA. This suggests an increase in the expression or accessibility of carbohydrate moieties during development. SBA and UEA showed little to no binding to adult or neonatal retina. Retinal vasculature was intensely stained by RCA, both during development and in the adult. All lectins binding to adult or neonatal retinal layers showed some degree of reactivity with the inner segment region of photoreceptor cells. However, only Con A, PNA and WGA bound to photoreceptor outer segments, suggesting significant differences in the glycosylated components of inner and outer segment membranes. PNA bound specifically to a subpopulation of photoreceptor cells and to discrete regions within the outer synaptic layer. The pattern of PNA binding suggests that this lectin binds preferentially to cone photoreceptor inner and outer segments and cone synaptic pedicles rather than to rod photoreceptor cells. This marked specificity of PNA binding suggests that it may provide a basis for the physical separation of cone and rod photoreceptor cells.     

Histopathological study of alobar holoprosencephaly

Summary Formalin-fixed and paraffin-embedded specimens of 24 human gliomas were examined histochemically with five lectins: concanavalin A (Con A), wheat germ agglutinin (WGA), Ricinus communis agglutinin 1 (RCA-1), peanut agglutinin (PNA), and Ulex europaeus agglutinin 1 (UEA-1). Although the staining intensity with lectins was variable, tumor cells in five astrocytomas, three oligodendrogliomas, six ependymomas, and one gliosarcoma, were generally positive for Con A, WGA, and RCA-1, and negative for PNA and UEA-1, whereas those in nine glioblastomas were usually positive for Con A and WGA and negative for RCA-1 and PNA as well as UEA-1. The malignancy in neoplastic astrocytes was correlated with the decrease in binding with lectins, especially RCA-1. Blood vessels, particularly the endothelial layers, in all gliomas were stained intensely with all lectins used. Macrophages showed two staining features with lectins; stippled and granular. The former macroplìages were positive for Con A, WGA, RCA-1, and PNA, and negative for UEA-1, whereas the latter macrophages were positive for all lectins used. Thus, the staining characteristics with lectins of macrophages were different from those of any glioma cells and very useful for identification of macrophages in gliomas.     

Distribution of glycoconjugates in gerbil hippocampal neurons--histochemical study with lectins]

Paraffin-embedded sections of gerbil hippocampus were made and stained by use of lectins with different sugar specificities: Concanavalin A (Con A), wheat germ agglutinin (WGA), Ricinus communis agglutinin (RCA), Phaseolus vulgaris agglutinin (PHA-E), peanut agglutinin (PNA), soybean agglutinin (SBA), and Vicia villosa agglutinin (VVA) to investigate the distribution of glycoconjugates in this brain region. Nuclear membranes of all the neurons in the hippocampus were positively stained with Con A and PHA-E, whereas WGA revealed definite staining of cell membranes. Endothelial cells of blood vessels were intensely positive to RCA, suggesting its usefulness as a marker of endothelial cells. With SBA and VVA, a few neurons in Ammon's horn were positively stained, while no positive cells were observed in the dentate gyrus. CA2 and the medial part of the CA1 were also positive bilaterally with SBA and VVA. Some neurons in Ammon's horn and dentate gyrus were selectively stained on the surface of their cell bodies with PNA. The present results show that lectins used distinguish different subpopulations of hippocampal neurons, indicating a new possible classification of hippocampal neurons based on their differences in glycoconjugates.     

Transneuronal transport of lectins

Axonal and transneuronal transport of the plant lectins wheat germ agglutinin (WGA), Pisum sativum agglutinin (PSA), Lens culinaris agglutinin (LCA), soybean agglutinin (SBA), peanut agglutinin (PNA), Concanavalin A agglutinin (Con A), and Ulex europeus agglutinin (UEA) were examined and compared using an immunocytochemical staining method. WGA, which binds to N-acetylglucosamine and sialic acid carbohydrate residues, and the 3 mannose binding lectins (Con A, PSA and LCA) were found to undergo retrograde transport to the facial nucleus after injection into the facial muscles, and anterograde transport to the optic tectum after injection in the vitreous, and to the spinal trigeminal nucleus caudalis after injection into the mystatial vibrissae. SBA showed a slight tendency to be transported retrogradely, but not in the anterograde direction, whereas UEA and PNA were not axonally transported in any of these systems. All lectins which were transported in the anterograde direction labeled neuronal somata in their respective terminal fields indicating that transneuronal transport had taken place. Axonal and transneuronal transport of the lectins appears to be dependent upon their respective carbohydrate affinities. Transneuronal transport which can be demonstrated for certain lectins indicates that mechanisms exist whereby neurons exchange large molecules which could be involved in mediating trophic and other influences on target cells.     

Glycoprotein pattern in human brain tumors studied using lectin binding after sodium dodecyl sulfate-gel electrophoresis and protein blotting

The immunoblotting technique was used to study the glycoproteins in human brain tumor samples including astrocytoma, glioblastoma, meningioma and oligodendroglioma, as well as in normal human brain. Glycoproteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis, electrophoretically transferred to nitrocellulose membrane and characterized, using binding with 11 different lectins. Tumor-associated glycoproteins were found using the lectins peanut agglutinin (PNA), soybean agglutinin, Limulus polyhemus, Lotus tetragonolobus, Ricinus communis 1, (RCA-1) and wheat germ agglutinin (WGA). Their molecular masses ranged from 50 to 180 kDa. Several of them were common to the 3 types of tumors: astrocytomas, oligodendrogliomas and meningiomas. PNA, RCA-1 and WGA were the 3 most feasible lectins with regard to tumor specificity, simplicity and reproducibility.     

Distribution of cellular carbohydrate moieties in human dysontogenetic brain tumors,especially in craniopharyngioma and epidermoid/dermoid

Summary Cellular carbohydrate moieties of 65 human dysontogenetic brain tumors (craniopharyngioma, epidermoid/dermoid, Rathke cleft cyst, germinoma and non-germinomatous germ-cell tumors) and 60 common brain tumors (glioma, meningioma, neurinoma and pituitary adenoma) were investigated histochemically using lections from Ulex europaeus (UEA-1), Dolichos biflorus (DBA), peanut (PNA) and soybean (SBA), and with anti-blood group A and Lewis^Y (Ley^Y) antibodies. In craniopharyngiomas and epidermoid/dermoids, it was found that PNA and SBA binding sites existed in suprabasal cells of the epithelium, and that antigen of either blood group A or H (demonstrable by UEA-1) existed in more differentiated epithelial cells compared to the results reported in normal human skin epidermis. Rathke cleft cysts were stained with PNA or SBA, and two out of three Rathke cleft cysts also expressed either H or A antigen. In addition, DBA binding sites, as well as Le^Y antigen, were frequently seen in craniopharyngiomas and Rathke cleft cysts, but they were entirely absent in the epithelium of epidermoid/dermoid. On the other hand, PNA and SBA reactivities was also found in common brain tumors, while blood group A, H and Le^Y antigens and DBA reactivity were almost absent in these tumors. These findings demonstrate that carbohydrate moieties such as those of blood group antigens reported to be found in human skin epidermis exist in a similar form in craniopharyngioma, epidermoid/dermoid and the Rathke cleft cyst. The identification of blood group A, H and Le^Y antigens and DBA reactivity in brain tumors seems to be considerably limited and specific. Thus, carbohydrate antigen reacting with DBA and the presence of Le^Y antigen might be distinguishing markers for craniopharyngioma as well as Rathke cleft cyst versus epidermoid/dermoid.     

Differential interaction of lectins with chemosensory receptors

L-Alanine and L-arginine bind with similar affinity (Kd 10(-7)-10(-6) M) to receptors in both a sedimentable fraction (P2) from taste epithelium and isolated olfactory cilia from the channel catfish, Ictalurus punctatus. Lectins of differing carbohydrate specificity were used to determine the glycoprotein nature of the chemosensory plasma membranes and to differentially affect receptors for L-alanine and L-arginine. The peroxidase-conjugated lectins concanavalin A (Con A), wheat germ agglutinin (WGA), and peanut agglutinin (PNA) were used to identify the glycoprotein components of the chemosensory plasma membranes after polyacrylamide gel electrophoresis. In both chemosensory membranes, numerous protein components were labelled by Con A and WGA. In contrast, a single predominant component was labeled by PNA in olfactory cilia, whereas several proteins in taste membranes were labeled by this lectin. When unconjugated lectins were preincubated with olfactory cilia, 60-70% of binding to L-alanine and L-arginine receptors was inhibited by Con A and WGA. PNA inhibited L-alanine but not L-arginine binding to olfactory receptors. Inhibition of olfactory receptor binding by lectins was time- and dose-dependent. By contrast, no inhibition of either L-alanine or L-arginine receptor binding in taste membranes was observed with any of the lectins. The differential labeling of the chemosensory membranes and the differential inhibition of receptor binding by lectins suggest that, despite ligand similarity, the chemosensory receptors in these membranes are not identical molecular species.     

Lectin histochemistry in the aged dog brain

Formalin-fixed and paraffin-embedded canine brains were examined histochemically using 15 selected lectins. Concanavalin A (Con A), Lens culinaris agglutinin, Lycopersicon esculentum agglutinin (LEL) and Limulus polyphemus agglutinin (LPA) labeled neurons in an age-dependent manner. These and some other lectins [Dolichos biflorus agglutinin (DBA), Vicia villosa agglutinin (VVA), Ricinus communis agglutinin 120 (RCA-I), Bandeiraea simplicifolia agglutinin (BSL-I), and Phaseolus vulagaris agglutinin-L (PHA-L)] also age-dependently labeled glial cells. These results indicate that monosaccharide composition and biochemical metabolism in brain cells change with age and that these lectins may be useful as histochemical markers for investigating senile changes in the canine brain. However, no significant correlation was found between ApopTag-positive and lectin-positive cells. Amyloid plaques were positive for Con A, DBA, Glycine maximus agglutinin (SBA), LEL, PHA-L, Limax flavus agglutinin (LFA) and VVA. Among these lectins, VVA, SBA and LFA intensely stained amyloid both in blood vessel walls and senile plaque cores. Therefore, the sugar residues recognized by these lectins likely play specific roles in β-amyloid deposition in the aged dog brain. Received: 2 June 1997 / Revised: 21 July 1997, 28 August 1997 / Accepted: 3 October 1997     

Ontogenetical study of the chick embryo subcommissural organ by lectin-histofluorescence and electronmicroscopy

Summary The secretory activity of the subcommissural organ (SCO) was studied during embryogenesis of the chick (Gallus gallus) using two lectins labelled with fluorescein isothiocyanate, concanavalin A (Con A) and wheat-germ agglutinin (WGA). While WGA labels the apical or ventricular border of the organ, Con A labels both, the apical and vascular poles of the cells. Glycoproteinaceous secretory products, visualized by Con A appear early, at 5 days, in the ependymal epithelium and expand progressively in a rostrocaudal direction. A correlation is established between histofluorescence and the ultrastructural aspects of the ependymocytes. This throws light on the role of the endoplasmic reticulum in the synthesis, storage and transport of the material produced by the SCO, and points to the existence of two poles of exchange between the secretory cells and the extracellular medium, i.e., the ventricular and the vascular one. WGA reactivity at the apical border is linked up with the formation of Reissner's fibre and shows that the secretory product of the SCO cells undergoes at least partly modifications during its intracytoplasmic transport preceding apical discharge.Dedicated to Prof. A. Oksche on his 60th birthday.     

Lectin histochemistry of plaques and tangles in Alzheimer's disease

Summary Biotinyl derivatives of several lectins and avidin-horseradish peroxidase were used to study the localization of glycoconjugates in amyloid plaques and in neuritic tangles in brains of patients with Alzheimer's disease (AD), Downs syndrome (DS) and Gerstmann-Sträussler syndrome (GSS). The lectins tested recognize the following residues: -d-galactosyl [Ricinus communis agglutinin 120, (RCA-1) and peanut agglutinin, (PNA)]; -d-galactosyl [Griffonia simplicifolia agglutinin (GSA)]; -d-mannosyl>-d-glucosyl [concanavalin A (Con A) andLens culinaris agglutinin (LcH)];N-acetyl- andN-glycolylneuraminic acid [Limax flavus agglutinin (LFA) andLimulus polyphemus agglutinin (LPA)];N-acetyl-glucosaminyl and sialyl [wheat germ agglutinin (WGA)];N-acetyl-d-galactosaminyl [Helix pomatia agglutinin (HPA) andDolichos biflorus agglutinin (DBA)] and -l-fucosyl [Ulex europeus agglutinin (UEA-1)]. The majority of lectins listed above bind preferentially to the peripheral area of AD plaques, whereas in plaques of DS they are mainly bound to central amyloid core. In neurofibrillary tangles of AD brains only residues recognized by WGA and HPA or DBA were found, whereas in DS brains, in addition to above mentioned, -d-galactose (RCA-1) and sialic acid (LFA) were also present. In brain microblood vessels the strongest reaction in endothelia appeared with UEA-1 and RCA-1, indicating the abundance of -l-fucosyl and -d-galactosyl residues. In AD brains deposits of amyloid were noted in the wall of some blood vessels, where monosaccharide residues recognized by RCA-1, GSA, UEA and WGA but not by Con A and LFA were present. However, our studies of some organs (liver, kidney, heart and testes) of patients with generalized amyloidosis revealed a lack of these sugar residues. It indicates, that the composition of amyloid present in brains of AD is different to that in other organs in generalized amyloidosis.Supported in part by grant no. AG 04220-03 from the National Institute of Aging, NIH     

Lectins are markers of neuronal migration and differentiation in rat brain

The binding of the lectins concanavalin A (Con A), peanut lectin (PNL), Ricinus communis agglutinin I (RCA I), Ulex europaeus agglutinin I (UEA I) and wheat germ agglutinin (WGA) to rat brains at several fetal and neonatal stages of development was evaluated. Cytochemical staining was performed using biotinylated lectins with an avidin-biotin complex with and without neuraminidase digestion. Differential binding to ventricular and intermediate layers, cortical plate and blood capillaries was demonstrated at different stages of development. WGA bound to blood capillaries at all ages, RCA I and PNL + N (PNL after neuraminidase digestion) from gestational day 22 on. During migration RCA I bound to cell fibers, PNL and UEA I to migrating cell bodies. Con A and UEA I stained perikaryonal structures of cortical neurons increasingly during neonatal development. It appears that cytochemical methods utilizing lectins can be used for the investigation of developmental processes of the central nervous system.     

Rod and cone specific domains in the interphotoreceptor matrix

The insoluble matrix domain of the interphotoreceptor matrix (IPM) from normal dog, cat, and mouse retinae were characterized using lectin cytochemistry. The lectins WGA (wheat germ agglutinin) and PNA (peanut agglutinin) were used to label interphotoreceptor matrix microdomains in cryosections of retinal tissue and in extracted insoluble matrix. Retinal cryosections and extracted matrix were examined by epifluorescence microscopy and scanning confocal laser microscopy, the latter allowed for the removal of all background fluorescence and gave increased resolution. The insoluble matrix was extracted as a continuous sheet that was comprised of two photoreceptor-specific matrix domains distinguished both by the size of the domains, and by differential binding of WGA and PNA lectins. Each domain encloses a photoreceptor inner and outer segment. Individual rod-associated domains were connected into a hexagonal lattice and this pattern was regularly interrupted by the larger cone-associated domains which have 8-10 surrounding rod domains. The PNA lectin primarily labeled the cone-associated matrix with faint binding to the rod matrix; the WGA lectin labeled both the rod- and cone-associated matrix.     

Lectin histochemistry of the metathoracic ganglion of the locust Schistocerca gregaria before and after axotomy of the tympanal nerve

The thoracic ganglia of insects exhibit a highly ordered organization. It seems possible that the information underlying the emergence of this order during development and its maintenance throughout insect life is given via a distinct pattern of molecules distributed within the ganglion. The question we asked was whether the adult insect ganglion is subdivided by the distribution of specific carbohydrates and furthermore whether or not this distribution changes during degeneration and regeneration of neurons. In order to determine the normal carbohydrate distribution, we stained sections of the intact metathoracic ganglion of the locust Schistocerca gregaria with fluorescence-coupled lectins. We succeeded in labeling three sensory neuropil areas with either peanut agglutinin (PNA): Phaseolus vulgaris erythrolectin (PVE), soybean agglutinin, wheat germ agglutinin (WGA), or Vicia villosa agglutinin. Apart from this, PNA, WGA, and succinylated WGA also selectively labeled some neuronal cell bodies, including dorsal unpaired median neurons. Datura stramonium lectin (DSL), Griffonia simplicifolia lectin II, and Solanum tuberosum lectin (STL) bound to glial cells or glia surrounding extracellular matrix. A few lectins stained all structures within the ganglion; some showed no binding at all. In the second part of our study, we tested whether carbohydrates were differentially regulated during transient deafferentation after the axotomy of the tympanal nerve. Binding of PNA and PVE within the auditory neuropil did not change. However, binding of the two glia-associated markers, DSL and STL, clearly differed from that found in intact animals; they bound transiently (day 3–4 until day 10–20 post-surgery) to axonal tracts and neuropils of the axotomized sensory afferents. J. Comp. Neurol. 387:255–265, 1997. © 1997 Wiley-Liss, Inc.     

Microscopic and biochemical characterization of lectin binding sites in the cephalopod retina

Using light and electron microscope cytochemistry and lectin blotting techniques, we have shown that the lectins concanavalin A (Con A), Ricinus communis agglutinin (RCA), and peanut agglutinin (PNA) bind to specific glycoconjugants in the adult cephalopod retina. For light microscope lectin cytochemistry, aldehyde-fixed, frozen, or Araldite-embedded, etched sections of cephalopod retinas were incubated with FITC- or TRITC-conjugated lectins and examined by using epifluorescence microscopy. Con A labeled structures in the entire retina including the inner limiting membrane (ILM), rhabdomeric membranes, interphotoreceptor matrix (IPM), and structures in the photoreceptor inner segments. RCA labeling was similar to that of Con A except that there was a decrease in the staining of the rhabdom tips near the ILM. PNA labeled only the interphotoreceptor matrix between apposing rhabdomeres. The intensity of staining of the IPM by PNA also decreased or was absent toward the rhabdom tips. None of the lectins labeled the myeloid bodies located in the photoreceptor inner segments. Electron microscope (EM) lectin cytochemistry was performed on aldehyde-fixed, LR White-embedded tissue or on Araldite-embedded, periodate-etched sections by using gold-conjugated lectins. EM results confirmed the observations made by light microscopy. Lectin blots with a retinal extract or light-sensitive membrane fraction revealed a variety of protein bands labeled by all three lectins. Con A and RCA labeled opsin and its aggregates whereas PNA did not. None of the lectins labeled retinochrome. The labeling of the cephalopod IPM by PNA suggests a structural similarity between the IPM of vertebrates and invertebrates. In other studies, we have demonstrated the presence of a retinoid binding protein in the IPM of cephalopods.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lectin binding sites and anionic components related to differentiation in the prenatal rat cerebral cortex

The location of lectin binding sites and of anionic components was studied in the embryonic rat cerebral cortex after the formation of the cortical plate at embryonic day 18. The cortical layers advanced in differentiation, i.e. the sub-plate region and the marginal zone, showed a predominant staining with peroxidase conjugates of wheat germ agglutinin (WGA), peanut agglutinin (PNA), and after immunocytochemical detection of PNA binding sites. This pattern was obtained also with the colloidal iron hydroxide staining method. In contrast to this, the binding of concanavalin A and of succinylated WGA did not reveal a prevalent staining of the sub-plate region and the marginal zone. The further histochemical analysis of the substances responsible for the selective staining of these layers was performed by lipid extractions and by enzymatic treatment of the tissue sections with trypsin, hyaluronidase or neuraminidase prior to the binding of lectins or colloidal iron. The results obtained indicated high concentrations of sialylated galactosylglycoproteins in coexistence with glycosaminoglycans. Electron microscopy was performed with peroxidase conjugates of WGA and PNA. Binding sites of both of the lectins in the sub-plate region and in the marginal zone were located mainly at cell surfaces of the different cellular structures. The most intensive binding of WGA and PNA was detected at the surface membranes and at intracellular material of amoeboid microglial cells and astrocyte-like cell processes. It can be concluded that in distinct brain areas during early differentiation specific glycoproteins in coexistence with glycosaminoglycans are situated at, or associated with cell surfaces in high concentrations. The identical histochemical features previously described in mesenchymal tissues suggest that these glycoconjugates might be related to common morphogenetic processes in which non-neuronal cells of brain and body are specifically involved.     

Lectin staining of saccharides in the normal and hypothyroid developing organ of Corti

Lectin staining has been used to detect mono- and oligosaccharides in normal and hypothyroid developing organs of Corti in the rat. Eight developmental stages were studied (1, 5, 8, 10, 15, 20, 50 and 60 days after birth). Congenital hypothyroidism was induced by oral administration of propylthyouracil to pregnant rats. Labelling of the tectorial membrane with 3 lectins, Ulex europaeus agglutinin-I (UEA-I), Lens culinaris agglutinin (LCA) and Ricinus communis agglutinin-I (RCA-I) showed no significant differences between normal and hypothyroid animals. Staining with peanut agglutinin (PNA) showed that the hypothyroid adult tectorial membrane (but not the normal one) possesses the disaccharide galactose + N-acetyl galactosamine. Phaseolus vulgaris agglutinin-L (PHA-L) labels the whole tectorial membrane in both groups of animals, but the staining is more intense in the hypothyroid one for a narrow band of oligosaccharide located just between the tectorial membrane and the underlying organ of K?lliker. Both soybean agglutinin (SBA) and succinylated wheat germ agglutinin (WGA) stain the tectorial membrane as well as the cytoplasm of the cells constituting the inner portion of the organ of K?lliker; this latter feature disappears in the normal animals about the 8th postnatal day, but it is abnormally preserved until the 60th postnatal day in the hypothyroid ones. In the adult hypothyroid animals, 3 of the lectins (LCA, PHA-L and WGA) stain extracellular conglomerates located under the synaptic pole of the outer hair cells.     

Changes in glucidic radicals in contused human brains

Changes in carbohydrate metabolism in brain injury and the involvement of numerous glycoproteins in the subsequent restoration phenomena orientated this paper towards reporting on glucidic radical distribution in postinjured brain tissue. Samples from nine patients suffering severe head injuries and three matched controls were studied. Autopsies were performed up to 24 h postmortem; brains were fixed in formalin and samples were taken from contusional, pericontusional and different brain regions including the anterior cingulum and corpus callosum, parasagittal gyrus, putamen, hippocampus and opercular areas embedded in paraffin. Hematoxylin-eosin staining, immunoreaction with glial fibrillary acid protein (GFAP) and biotin-conjugated lectins (RCA, UEA, PNA, concanavalin A (Con A) and WGA) were used. Contusion and related phenomena such as ischemia induced changes in lectin expression in several elements of the nervous tissue. Endothelial cells of contused areas were positive for RCA, UEA and progressively for WGA and Con A, which could be related to hemorheological disturbances inducing secondary brain damage. Neurons in affected areas were also stained for Con A and UEA, with some processes being delineated. Axonal swellings showed particular affinity to any lectin. Reactive astrocytes displaying only mild staining to WGA in cell bodies were strongly positive for GFAP, showing different patterns of reactivity in the cortex and in white matter.     

Lectin histochemistry of the rat brain following thioacetamide-induced hepatic failure

Biotinyl derivatives of several lectins were used to study the localization of glycoconjugates in the cerebral microcapillaries and various brains of rats given at 24-h intervals two ip administrations of a hepatotoxin-thioacetamide (TAA) and examined 21 d posttreatment. At this time, the rats were asymptomatic with regard to hepatic encephalopathy but showed specific and selective changes in the blood-brain-barrier (BBB) transport of basic amino acid, but no BBB damage, and region-specific neuronal injury in the hippocampus and neocortex. The lectins tested recognized the following sugar residues: β-d-galactosyl (Ricinus communis agglutinin [RCA-1]);N-acetyl-glucosaminyl andN-acetyl-neuraminic acid (wheat-germ agglutinin [WGA]);N-acetyl-d-galactosaminyl (Helix pomatia agglutinin [HPA]); β-d-galactosyl andd-galactosyl neuraminic acid (peanut agglutinin [PNA]), and α-d-galactosyl and α-d-mannosyl (concanavalin A [Con A]). The treatment markedly decreased the binding to the cerebromicrovascular network of the hippocampus and neocortex of RCA-1 and WGA. The binding of these two lectins to their complementary monosaccharide residues appears to reflect subtle changes in BBB function, with a detection threshold below the conventional BBB permeability tests. The changes in the binding of the other two lectins: an increase of HPA binding and a decrease of Con A binding, confined to neocortical neurons and pyramidal cells of hippocampus injured by TAA treatment.