Lectin-binding spectra in the hyperplastic human tonsil. Effect of formalin fixation and paraffin embedding on lectin affinity of tissue components

A study of glycoconjugates in nasopharyngeal carcinoma with correlation to clinical transformation

Little is known about the glycoconjugate changes in human nasopharyngeal epithelium following neoplastic changes. Glycoconjugate histochemistry (Glycine maximus (SBA), Griffonia simplicifolia II (GSA-II), Ulex europaeus (UEA-I), Arachis hypogaea (PNA) and Canavalia ensiformis (ConA)) were performed on the following nasopharyngeal biopsies: 10 adenoid tissues (benign controls), 10 chronic inflammation, 20 squamous metaplasia, 20 undifferentiated carcinoma and 5 squamous cell carcinoma. These results were correlated with the clinical transformations findings. Strong ConA and PNA staining (after neuraminidase treatment (NA)) characterized a subpopulation of squamous metaplasia subjects who later transformed to nasopharyngeal carcinoma. Strong ConA and PNA (before and after NA) depicted the majority of undifferentiated carcinoma subjects having local recurrence following irradiation therapy. In squamous metaplasia, ConA and PNA (after NA) staining may serve as a warning sign for neoplastic changes. Strong stainings for ConA and PNA (before and after NA) in undifferentiated carcinoma subjects may predict a risk for local recurrence.

Peanut agglutinin lectin immunohistochemical staining of normal and neoplastic canine tissues

Peanut lectin binding sites were demonstrated in normal canine tissues and in 114 canine tumors by avidin biotin complex immunohistochemical staining on unfixed cryostat tissue sections. Peanut agglutinin (PNA) receptors occurred in a variety of normal cells and tissues, including lymphoid follicle center cells; cortical thymocytes; basal cells and the stratum spinosum of stratified squamous epithelium; columnar epithelium of the gastrointestinal tract; parietal cells and chief cells of the stomach; some endothelial cells; myelin; chondrocytes; spermatogenic cells; cells of the adrenal medulla; Bowman's capsule and the distal convoluted tubules of the kidney; prostatic, perianal and endometrial epithelium; and the extracellular matrix of connective tissues. Neoplastic cell staining was sporadic and was most often observed in benign or well-differentiated neoplastic tissues in which the corresponding normal cells also expressed PNA binding sites. However, PNA also bound to some tumor cells in which the analogous normal tissues were unstained, including cells of some fibrosarcomas, rhabdomyosarcomas, hemangiopericytomas and proliferating myoepithelial cells in mixed mammary tumors. Although PNA binding is complex and heterogeneous in canine tissues and does not appear to immunohistochemically detect a moiety associated with neoplastic transformation per se in the majority of canine tumors, the expression of PNA receptors may be associated with neoplastic changes in some mesenchymal cell populations.

Altered lectin binding sites in keratoconus corneas

We investigated the glycoconjugates in frozen sections of keratoconus corneas, using a panel of 12 biotin- or fluorescein isothiocyanate-labeled lectins. No differences between the lectin binding sites of the epithelium, endothelium and Descemet's membrane of normal and keratoconus corneas could be observed. However, in contrast to normal corneas, intense staining with peanut agglutinin (PNA) could be detected at breaks in Bowman's layer, in scar tissue and in the adjacent stroma. Furthermore, in the majority of cases binding sites for Phaseolus vulgaris erythroagglutinin (PHA-E) and increased staining with Ricinus communis agglutinin I (RCA-I) and Lens culinaris agglutinin (LCA) could also be detected in ruptures in Bowman's layer and in scar tissue. These data suggest that the scarred regions of the anterior stroma in keratoconus corneas may contain oligosaccharides with terminal D-galactose (beta 1-3)-D-N-acetylgalactosamine disaccharides (recognized by PNA), increased amounts of glycoconjugates with terminal beta-galactose residues (recognized by RCA-I), increased amounts of glycoconjugates with glucose/mannose residues (recognized by LCA), and finally, biantennary complex-type glycopeptides containing two outer galactose residues and a residue of N-acetylglucosamine (recognized by PHA-E). Since corneal scars due to causes other than keratoconus revealed lectin binding sites (particularly for PNA and to a lesser extent also for PHA-E, LCA and RCA-I) similar to those seen in scar tissue of keratoconus corneas, we conclude that it is mainly scar formation that may be responsible for the altered lectin binding sites in keratoconus.

Pulmonary tumor thrombotic microangiopathy with pulmonary hypertension

Pulmonary tumor thrombotic microangiopathy is characterized by fibrocellular intimal proliferation of small pulmonary arteries and arterioles in patients with metastatic carcinoma. Its morphologic features, including precursor lesions, were studied in 21 patients diagnosed in 630 consecutive autopsy cases with carcinoma (3.3%). Nineteen of 21 patients had adenocarcinoma and 11 of these 19 patients had gastric carcinoma. The pathogenetic events start with microscopic tumor cell embolism. Tumor emboli do not occlude affected vessels but induce both local activation of coagulation and fibrocellular intimal proliferation, which lead into stenosis or occlusion. Hemodynamically, an increase in vascular resistance results in pulmonary hypertension. In three patients, metastatic carcinoma was unknown before death, and the condition was diagnosed as pulmonary hypertension of unknown origin. Thus, pulmonary tumor thrombotic microangiopathy should be considered in the differential diagnosis of primary pulmonary hypertension, particularly in patients with well-known carcinoma who develop acute or subacute cor pulmonale.

Phenotypic characterization of normal and neoplastic canine endothelial cells by lectin histochemistry

Cell surface glycoconjugate expression of endothelial cells in canine cutaneous hemangiomas and hemangiosarcomas was compared to normal cutaneous endothelial cells using eight different lectins (with and without neuraminidase pretreatment) in an indirect immunoperoxidase technique. Direct comparison of lectin binding pattern of neoplastic endothelial cells with adjacent normal endothelial cells revealed minor changes in the binding intensity of several lectins (enhanced: Wheat germ agglutinin [WGA]; reduced: Griffonia simplicifolia-I [GS-I], Ricinus communis agglutinin-I [RCA-I], Soybean agglutinin after neuraminidase pretreatment [Neu-SBA], and Wheat germ agglutinin after neuraminidase treatment [Neu-WGA]). Neoplastic endothelial cells in some tumors exhibited varying binding of Ulex europaeus agglutinin-I (UEA-I; not binding to normal canine endothelial cells) and no Soybean agglutinin (SBA) binding (variably binding to normal endothelial cells in small cutaneous vessels). Lectin binding of neoplastic cells was rather heterogenous within one tumor compared to the uniform binding pattern of normal endothelial cells. These lectin binding studies demonstrate the phenotypic heterogeneity of neoplastic endothelial cells, indicating changes of cell surface glycosylation during neoplastic transformation.

Histocytochemistry of glycoconjugates in tonsillar tissues

Glycoproteins in palatine tonsillar epithelium were examined histochemically using seven different kinds of lectins to elucidate their functional morphology. UEA-I and WGA affinities, which might be altered due to an inflammatory reaction of the stroma, were detected selectively in the epithelial cell surface. Reacting products of SBA and GS-II were observed characteristically in the spinous and granular layers. No PNA, BPA and DBA activities were found in the tonsillar epithelium. These results suggest that carbohydrates on cell membranes might be changed according to the epithelial cell differentiation and some factors from the stroma.

The effects of various fixatives on subsequent lectin binding to tissue sections

The effects of ten fixation protocols on the subsequent binding of eight lectins to various mouse tissue sites have been systematically evaluated. The fixatives used were neutral and buffered formalin-saline, Bouin's fluid, 95% ethanol, Carnoy's fluid, calcium acetate-paraformaldehyde, and mercuric chloride both before and after removal of mercury pigment. These were compared with frozen sections of unfixed tissue and frozen sections post fixed in paraformaldehyde. Lectins used were PNA, DBA, SBA, BPA, UEA 1, GS I, GS II and MPA. Ethanol was found to be the superior fixative, closely followed by mercuric chloride. Paraformaldehyde was a poor fixative of both paraffin and frozen sections. It is recommended that, where a choice is possible, the fixation protocol appropriate to the particular lectin and tissue binding site is selected. Within certain limitations, formalin-saline proved an adequate fixative for the study of routine paraffin-processed tissue sections.

Lectin binding and surface glycoprotein pattern of human macrophage populations

In the present study unstimulated and stimulated human blood monocytes, untreated and phorbol ester treated U-937 cells, as well as human peritoneal and alveolar macrophages were studied with respect to their surface membrane properties. Binding of different lectins and electrophoretic patterns of tritium labeled surface glycoproteins were compared. The analysis of surface glycoproteins could be interpreted as evidence for a common origin of the analysed cell populations. Furthermore, banding patterns of glycoproteins might be useful to define certain activation states within monocyte/macrophage differentiation. In contrast, lectin binding pattern did not clearly discriminate macrophage subpopulations.

Affinity cytochemistry of vascular endothelia in brain tumors by biotinylated Ulex europaeus type I lectin (UEA I)

The vascularization of 50 tumors of the central nervous system (CNS) including 17 meningiomas, 25 neuroectodermal tumors, i.e., astrocytomas, oligodendrogliomas, mixed gliomas, glioblastomas, medulloblastomas, seven metastatic carcinomas, and one malignant hemangioendothelioma were investigated using biotinylated Ulex europaeus type I lectin (UEA I) in an indirect avidinbiotin-peroxidase procedure. The cytochemical staining pattern of UEA I on paraffin sections was compared with that of biotinylated Dolichos biflorus lectin (DBA), and with the immunocytochemical staining of factor VIII related antigen (F VIII/RAG) by polyclonal antisera using the PAP technique. UEA I visualized the endothelia of blood vessels with equal intensity, sensitivity, and reliability in normal brain and in tumor tissue with neovascularization. While large, medium, and small vessels were equally well demonstrated by UEA I and antibodies against FVIII/RAG, capillaries and endothelial sprouts were stained more consistently and intensely by UEA I. No reliable cytochemical staining could be obtained by DBA regardless of tissue or cell type investigated. It is concluded that UEA I is a highly useful cytochemical marker for the identification of vascular endothelia in paraffin sections of human brain tumors.

Lymphoepithelial carcinoma (Schmincke type) as a derivate of the tonsillar crypt epithelium

Ten tumours of tonsillar or epipharyngeal localization showing the histological picture of "lymphoepithelial carcinoma" (Schmincke 1921) were examined immunohistochemically using Peanut lectin, Ulex europaeus lectin-I and an antiserum to S-100 protein. The findings suggest a close relationship of this type of carcinoma to the normal tonsillar crypt epithelium. The majority of tumour cells are UEA-I-positive and PNL-negative, as is the crypt epithelium, while oral mucosa is both PNL- and to a lesser extent UEA-I-reactive. Tumour areas expressing this pattern contain a large number of asteroid-shaped PNL-positive histiocytes and arachnoid-shaped histiocytes reacting with anti-S-100 protein; both cell types being probably identical and representing typical elements of the normal tonsillar crypt epithelium. Consequently, the WHO-term "nasopharyngeal carcinoma, undifferentiated type" seems to be inadequate for this type of tumour.