The binding of peroxidase-labelled lectins to human breast epithelium. I--Normal, hyperplastic and lactating breast

Lectins as versatile tools to explore cellular glycosylation

Lectins are naturally occurring carbohydrate-binding proteins that are ubiquitous in nature and highly selective for their, often incompletely characterised, binding partners. From their discovery in the late 1880s to the present day, they have provided a broad palette of versatile tools for exploring the glycosylation of cells and tissues and for uncovering the myriad functions of glycosylation in biological systems. The technique of lectin histochemistry, used to map the glycosylation of tissues, has been instrumental in revealing the changing profile of cellular glycosylation in development, health and disease. It has been especially enlightening in revealing fundamental alterations in cellular glycosylation that accompany cancer development and metastasis, and has facilitated the identification of glycosylated biomarkers that can predict prognosis and may have utility in development of early detection and screening, Moreover, it has led to insights into the functional role of glycosylation in healthy tissues and in the processes underlying disease. Recent advances in biotechnology mean that our understanding of the precise binding partners of lectins is improving and an ever-wider range of lectins are available, including recombinant human lectins and lectins with enhanced, engineered properties. Moreover, use of traditional histochemistry to support a broad range of cutting-edge technologies and the development of high throughout microarray platforms opens the way for ever more sophisticated mapping - and understanding - of the glycome.

Lectin histochemistry for light and electron microscopy

Glycoconjugates are complex macromolecules present in all tissues throughout the body. Depending on the tissue region, glycoconjugates express different carbohydrate moieties, which can be used to both distinguish cell type and examine changes in cell phenotype.Although the periodic acid-schiff (PAS) method has long been used to study the distribution of glycoconjugates, the usefulness of the technique is severely limited by its lack of specificity. A more specific technique makes use of the affinity that plant-derived lectins have for different carbohydrate moieties in glycoconjugates. Binding of lectins is therefore a particularly useful adjunct to conventional histology when it is important to characterise cell type. These well-characterised binding patterns have proved particularly valuable in helping us understand the pathogenesis of kidney disease, changes in cell surface carbohydrates on normal and neoplastic cells in tumours, and blood group biology.When labeled with a reporter molecule such as biotin or gold, lectin binding can be easily identified using light and electron microscopy. In this chapter, we describe the appropriate experimental protocols for light and electron microscopic examination of lectin binding, emphasising their utility in characterising nephron segments in renal disease.

The loss of lectin reactivity from human endometrium is a feature of malignant change

Changes in the cell surface glycoproteins were investigated in endometrial adenocarcinomas using eight biotin-labelled lectins (Con A, LCA, WGA, e-PHA, l-PHA, SBA, PNA, LTA) which select for the major classes of N-linked and O-linked oligosaccharides. The tissues studied were 14 normal endometria, 20 cases of simple hyperplasia and 30 endometrial adenocarcinomas. Sections were cut at 5 microns from formalin fixed paraffin embedded blocks and were stained with an avidin-peroxidase method. All normal and hyperplastic endometria contained the full range of expected saccharides (positive staining for Con A, LCA, WGA, SBA, PNA, LTA, e-PHA and l-PHA). By contrast, over half of the endometrial adenocarcinomas exhibited a loss of galactosamine (56.7%) and over a third of them failed to reveal galactose (36.7%) and fucose (30.0%) (negative staining for SBA, PNA and LTA, respectively). Interestingly, following neuraminidase treatment, galactose was identified in all adenocarcinomas studied, but the expression of galactosamine and fucose was unaffected. There was a discrete linear staining at the level of the basement membranes in a proportion of endometrial glands treated with e-PHA, l-PHA and LCA; this was continuous in normal and hyperplastic endometria, while it was fragmentary in endometrial adenocarcinomas. The loss of galactosamine reactivity from endometrial adenocarcinomas was significantly correlated with high grade differentiation, and also with the more frequent occurrence of a poor oestrogen (ER) and progesterone (PR) receptor status and with an unfavourable 5-year survival. No relationship was found between fucose reactivity and tumour differentiation, stage of disease, hormone receptor status or prognosis. It is concluded that galactosamine loss, together with reduced fucose expression, is a common feature of endometrial malignancy, and that galactosamine deficient tumours may reflect a more aggressive biological behaviour.

Biochemical, histochemical and cell biological investigations on the actions of mistletoe lectins I, II and III with human breast cancer cell lines

Cytotoxicity of the mistletoe lectins I, II and III towards six human breast cancer cell lines was assessed using the Mossman assay. In addition, binding of the three mistletoe lectins to the separated membrane glycoproteins of these cell lines, the binding and uptake of these lectins into the cells in tissue culture and the binding of the lectins to histological preparations of these cell lines were analysed. The results indicate that there are quantitative differences concerning the toxicity of these three lectins towards the different cell lines. Furthermore, the lectin binding pattern in the cell lines differed. In Western blots, several membrane glycoproteins were labelled by the lectins. Our results indicate subtle differences between the three lectins with regard to the parameters mentioned above; however, the toxicity of all three lectins from mistletoe is so similar that they all seem suitable for the construction of immunotoxins.

Histochemical study of lectin binding in the human fetal minor salivary glands

The emerging synthesis of glycoconjugates containing specific oligosaccharides in developing human fetal labial and lingual salivary glands has been investigated by lectin histochemistry. An avidin-biotin technique was used to study the binding of lectins from Ulex europeus I (UEA-I), Dolichos biflorus (DBA), Glycine maximus (SBA), Helix pomatia (HPA), Arachis hypogaea (PNA) and Triticum vulgare (WGA) to specific sugars on sections of tissue from labial glands, glands of Blandin and Nuhn, glands of von Ebner and the dorsoposterior lingual salivary glands. Incipient synthesis of glycoconjugates in early glands and their presence in the cells and ducts of the later glands was shown. The study also showed a time-related increase in both staining intensity and binding sites of serous acinar cells from all glands and for all lectins used. For mucous cells, peak intensity of staining was reached by the middle phase of development. During later gland development this intensity was maintained in dorsoposterior lingual glands but tended to decline in labial glands. The various lectins showed different degrees of binding but UEA-I lectin generally bound the L-fucose sugar group in all salivary glands at all gestational ages. The results showed that lectins appear to bind to the oligosaccharides on epithelial cell surfaces of fetal salivary glands at all stages of development. The degree of change depends upon the stage of differentiation and maturation of the glands.

Expression of lectin-specific cellular glycoconjugates during oral carcinogenesis

The binding pattern of two lectins, concanavalin A (ConA) and peanut agglutin (PNA), in various phases of tumour progression in the oral epithelium was studied. These included non-dysplastic, dysplastic and neoplastic lesions as well as normal tissue. ConA and PNA showed intense staining in the basement membrane of all types of lesions. Little difference was observed in the staining patterns between different stages of oral carcinogenesis, either with ConA or PNA. ConA showed mild cytoplasmic and membrane staining in all types of lesions while PNA showed moderate to intense staining in both the cytoplasm and membrane of lower-layer cells in all histological groups. The present study therefore shows that these lectins have limited value in the elucidation of oral carcinogenesis and are of insignificant diagnostic value.

Endothelial cell seeding: a review

The concept of endothelial cell seeding, designed to provide vascular grafts with a nonthrombogenic lining, has progressed from crude animal experiments during the past two decades to detailed in vitro functional studies using human cells. Although favorable results have been obtained in animal studies this has yet to be translated to humans, where current application of these techniques has been limited to a very few clinical trials. The history, current status and future directions are reviewed herein.

Lectin binding patterns in normal liver, chronic active hepatitis, liver cirrhosis, and hepatocellular carcinoma. An immunohistochemical and immunoelectron microscopic study

We studied the binding patterns of 14 lectins in human normal and cirrhotic liver (LC) tissues and hepatocellular carcinomas (HCC) using the ABC method. Lectins were divided into 4 groups according to their binding patterns in normal tissues: (A) PHA, MPA, LcH, RCA-I, and WGA, which bound to hepatocytes and all three types of sinusoidal cells; (B) BPA, GS-I, PNA, and SBA, which bound to Kupffer cells and endothelia of interlobular arteries and veins and bile duct epithelia in the portal tract, but not to hepatocytes; (C) UEA-I, which bound only to endothelia of interlobular arteries and veins and bile duct epithelia in the portal tract; (D) LBA, Lotus, LPA, and SJA, which showed no binding. Thus group B lectins may be useful markers of Kupffer cells. Only electron microscopic examination revealed the precise binding sites of lectins in sinusoidal cells and hepatocytes. Hepatocyte cell surface polarities demonstrated by lectin binding in LC and HCC were different from those in the normal liver. The binding pattern of PHA to LC hepatocytes changed from a membranous to both a membranous and a cytoplasmic pattern, and that of LcH to HCC cells changed to dot-like staining in the cytoplasm. These changes of polarities in LC and HCC might be caused by changes in the distribution of lectin-binding carbohydrates or by the altered glycosylation of glycoconjugates.

Comprehensive lectin histochemistry of normal and neoplastic human choroid plexus cells: alternation of lectin-binding patterns through neoplastic transformation

Lectin histochemistry of the normal and neoplastic human choroid plexus cells [six choroid plexus papillomas (CPPs) and three choroid plexus carcinomas (CPCs)] was performed using eight representative lectins to study the development of sugar chain structures and also to determine whether lectins were useful for a histopathological diagnosis of choroid plexus neoplasms (CPNs). The normal choroid plexus cells reacted with Ricinus communis (RCA-I). Canavalia ensiformis (Con A), Limax flavus (LFA) and Triticum vulgaris (WGA), while Arachis hypoaea (PNA) stained them only after the removal of sialic acid. Human fetal choroid plexus cells at 8 weeks gestation already showed the same lectin-binding patterns as adult ones. All CPNs were stained by RCA-I and Con A in a similar manner as the normal choroid plexus cells. Although seven CPNs were positive for LFA, two CPCs were not stained by LFA, which bound to sialic acid. Two LFA-positive CPPs were stained by PNA before the removal of sialic acid. Moreover, unlike the normal choroid plexus cells, Ulex europaeus-, Glycine maximus- and Dolichos biflorus-binding sites often appeared, and WGA-binding sites of three CPNs remained even after sialic acid removal. In conclusion, the glycosialylation in normal choroid plexus cells was completed during the early embryonic stage. The lectin-binding patterns of CPNs were heterogenous in each case. The alternation of the glycosialylation and/or acquisition of binding sites for some lectins was sometimes observed through a neoplastic transformation.

The use of lectins in histopathology

Lectins are proteins and glycoproteins extracted predominantly from plants which have the capacity to bind sugars specifically. This property makes them of interest for histopathology since they will bind to saccharides forming parts of glycoproteins and glycolipids of tissue constituents. Lectins have and can be used as reagents for mucin histochemistry, to identify specific cells, in the recognition of glycoprotein alterations in disease states, in studies of infectious diseases, and in the assessment of glycoconjugate alterations occurring with malignancy. They can be used for both light microscopic and ultrastructural localisation and various methods are available. It is important though, to consider the nature of the glycoconjugates under study and select lectins appropriately because of their varying specificities and binding characteristics. A panel of lectins should be used to study a particular configuration. Care should be taken with tissue fixation and processing. It must be remembered that an open and critical mind should be kept concerning interpretation of results. At the present time lectins have a limited value diagnostically, but the binding of Ulex europeus agglutinin to endothelium is certainly of value.

Lectin binding in tissues from hydatidiform mole, invasive mole and choriocarcinoma to concanavalin-A, wheat germ agglutinin and peanut agglutinin

A light microscopic analysis of lectin receptors in normal placenta and trophoblastic disease was performed utilizing biotinylated Concanavalin-A (Con-A), wheat germ agglutinin (WGA), and peanut agglutinin (PNA), in conjunction with an avidin-biotin peroxidase complex. Hydatidiform mole, invasive mole and choriocarcinoma exhibited increased receptors to Con-A and WGA compared to normal placenta. Increased reactivity to Con-A and WGA was associated merely with increased growth and proliferation of trophoblasts rather than a malignant transformation. Normal placenta, partial and complete mole generally showed moderate to strong binding with PNA after neuraminidase treatment, while invasive mole and choriocarcinoma (11 of 15 cases) generally showed minimal to absent reaction with PNA. Heterogeneity of PNA binding in choriocarcinoma was manifested by the presence of PNA reactivity in the trophoblast membrane in 2 cases wherein no prior neuraminidase treatment was given. This suggests that in some malignant trophoblasts, there is absence of sialic acid in the terminal cell surface carbohydrate groups resulting in the exposure of N-acetylgalactoseamine.

Studies of lectin binding to the human cervix uteri: II. Cervical intraepithelial neoplasia and invasive squamous carcinoma

The cell surface carbohydrate profile of formalin-fixed paraffin-embedded tissue sections of neoplastic cervical squamous epithelium was evaluated using lectins of Bauhinia purpurea (BPA), Canavalin ensiformis (Con A), Griffonia simplicifolia I (GS I), Griffonia simplicifolia II (GS II), Maclura pomifera (MPA), Archis hypogaea (PNA), Glycine max (SBA), Ulex europaeus I (UEA I) and Triticum vulgaris (WGA). Three lectins (BPA, Con A and PNA) showed a similar pattern of staining in both normal squamous epithelium and in cervical intraepithelial neoplasia (CIN). Variable alterations were seen in lectin-binding patterns in CIN with seven lectins (GS I, GS II, MPA, PNA, SBA, UEA I and WGA). A significant difference was seen between the intensity of staining of normal squamous epithelium and CIN with all lectins except WGA. The alteration in GS II-binding pattern and intensity was significantly related to grade of CIN. No correlation was found between lectin binding and the presence of koilocytes in squamous epithelium. Cases of invasive squamous carcinoma showed a heterogeneous lectin-binding pattern and no significant association was found between lectin binding and tumour differentiation of patient survival. These results indicate that neoplasia in cervical squamous epithelium is associated with alterations in terminal alpha-Man residues, alpha- and beta-GalNAc residues, alpha- and beta-GlcNAc residues, alpha- and beta-Gal residues, and alpha-Fuc-containing residues, present in the outer parts of both N-linked and O-linked glycoconjugates. The implications of these findings are discussed.

Studies of lectin binding to the human cervix uteri: I. Normal cervix

Lectins of Bauhinia purpurea (BPA), Canavalin ensiformis (Con A), Griffonia simplicifolia I (GS I), Griffonia simplicifolia II (GS II), Maclura pomifera (MPA), Arachis hypogaea (PNA), Glycine max (SBA), Ulex europaeus I (UEA I) and Triticum vulgaris (WGA) were used to evaluate cell surface carbohydrates in formalin-fixed paraffin-embedded tissue sections of normal human cervix uteri. Consistent patterns of staining of the squamous epithelium were obtained in all 30 cases with BPA, GS II, MPA, PNA, SBA and WGA. A variable distribution of lectin binding was seen in squamous epithelium with Con A, GS I and UEA I. The patterns of GS I and GS II binding reflected squamous epithelial maturation. Columnar epithelium did not stain with GS II, stained variably with Con A, and stained consistently with the remaining seven lectins in all cases. No association between lectin binding and blood group or phase of the menstrual cycle was found. These findings may be used as a baseline for evaluation of lectin binding in both preinvasive and invasive lesions of the cervix uteri.

The binding of peroxidase-labelled lectins to human endometrium in normal cyclical endometrium and endometrial adenocarcinoma

The nature of endometrial glycoconjugates throughout the menstrual cycle was investigated using a panel of lectins directed against specific sugar groups. This approach was also applied to a series of endometrial adenocarcinomas the findings for which were compared with those of normal controls. A change in the expression of glycosubstances was found in relation to the phase of the menstrual cycle; that there was increasing sialylation of terminal galactose groups during the secretory phase. This change may be influenced by progesterone. One group of endometrial adenocarcinomas exhibited binding patterns similar to those seen in secretory endometrium and this may be related to progesterone receptor state. Expression of fucose containing glycosubstances was identified in half of the carcinomas but not in the normal control tissue, thus indicating that a change in fucosylation occurs with endometrial neoplasia. None of the lectin binding patterns, however, correlated with variables in the patients themselves or within the tumours.

Cellular carbohydrate components in human, rabbit and rat lacrimal gland. Studies using fluorescein and peroxidase labelled lectins

Orbital lacrimal glands from adult male and female rabbits, rats and humans were examined for the presence of intracellular receptors of four lectins: concanavalin-A agglutinin, lutus tetragonolobus agglutinin, ricinus comunis-60 agglutinin and wheat-germ agglutinin using fluorescein-conjugated lectin and peroxidase labelling methods for fluorescence and electron microscopy, respectively. Lectins were used as specific probes to detect carbohydrate moiety of the lacrimal gland. The pattern of labelling with the lectins suggests that N-acetyl-glucosamine, N-acetyl-D-galactosamine, D-galactose, D-mannose, sialic acid and L-fucose are contained in the lacrimal gland of the three species. The significance of these findings is discussed.

Analysis of glycoproteins released from benign and malignant human breast: changes in size and fucosylation with malignancy

Radiolabelled glycoproteins released into media from benign and malignant human breast tissue after 48 h organ culture have been analysed using SDS polyacrylamide gel electrophoresis and fluorography. Major differences were identified between benign and malignant tissues: (i) a considerably higher incidence of glycoproteins in the molecular weight range 210-280 kDa detected from carcinomas than benign samples, with incidence being greater in poorly differentiated tumours; (ii) fucosylation of these glycoproteins released from carcinomas but not benign breast; (iii) heterogeneity, particularly of fucosylation, between the carcinomas but consistency amongst benign breast. A glycoprotein of MW 230 kDa was of particular interest since it was not detected from any benign samples but was present in 11 of 17 carcinomas, when it was almost always fucosylated. This could prove to be a useful tumour marker.

Lectin binding in the male breast

Twenty-four male breast lesions including ten normal, ten gynaecomastia, and four infiltrating carcinomas were studied for the presence and distribution of lectin binding carbohydrates. For comparison, tissue sections of five normal female breast lesions, ten each of fibrocystic disease, fibroadenoma, and carcinoma, were also included in this study. Formalin-fixed, paraffin-embedded tissues were tested with Glycine maximus (SBA), Dolichos biflorus (DBA), Triticum vulgaris (WGA), Concanavalia ensiformis (Con A), Lotus tetragonolobus (LTA), Arachis hypogaea (PNA), and Bandeiraea simplicifolia (BSAI). The lectin-binding patterns were similar in normal, gynaecomastia, and carcinoma, and were not pathognomonic to any male breast lesion. These lectin reactive patterns in the male breast appear to be similar to those reported for the female breast lesions.

The distribution of lectin receptor sites in human breast lesions

Conflicting data regarding the status of A, B, H and T antigens in epithelium of normal, mastopathies, fibroadenomas and carcinomas of the breast stimulated us to re-examine the carbohydrate residues in these condition. Currently, we extended the number of carbohydrate residues studied by using ten different biotinylated lectins as probes and avidin-biotin-peroxidase complex (ABC) as a visualant. In addition, the pattern of lectin staining of cancerous cells in primary and metastatic sites was compared. In primary and metastatic breast carcinomas, lectin receptor sites were stained more intensely with Concanavalia ensiformi agglutinin (*Con A), Ricinus communis agglutinin-I (RCA-I) and wheat germ agglutinin (WGA), than in normal breast, in mastopathies or in fibroadenomas. Cryptic receptor sites for peanut agglutinin (PNA) were stained in all cases of breast carcinomas, while free PNA sites stained only in a few cases of well-differentiated carcinomas. Receptors sites for Ulex europaeus agglutinin-I (UEA-I) stained non-malignant epithelium of patients with blood group H but did not stain malignant cells. The results show significant differences in lectin-binding patterns and staining intensities between normal and non-malignant, and malignant epithelial breast cells. Furthermore, these results indicate that in malignant cells, there is an increased content of sialic acid-rich carbohydrates but not of asialylated glycoconjugates.

Endothelial cell adhesion to vascular prosthetic surfaces

Improving the long term patency of small diameter prosthetic grafts remains an important but elusive objective in vascular surgery. In pursuit of a non-thrombogenic surface, we have cultured human-adult endothelial cells, examined their adhesive properties and their ability to colonize the inner surface of a Dacron graft. To examine cell adhesion, endothelial cells were labelled with 111In-oxine and inoculated onto prosthetic wells previously prepared with either cold insoluble globulin (CIG), 1% gelatin, alginate or left untreated as a control. At 100 min, mean percentage adhesion to CIG and gelatin precoated wells was 86.0 +/- 9.9% (+/- SD) and 81.6 +/- 2.9% respectively, whereas alginate at 57.5 +/- 7.5% and the control well at 48.3 +/- 9.9% showed significantly less adhesion. Further experiments examined the adhesion of Indiumoxine labelled endothelial cells to Dacron graft (2 cm X 6 mm ID) placed in an in vitro arterial circuit. An immediate loss of approximately 20% of the cells occurred within the first 30 s, whereafter, a stable population were adherent to the graft material. By 102 min, 73.4 +/- 1.8% of cells remained attached when exposed to tissue culture medium, but only 64.1 +/- 6.9% after exposure to blood. Cultured human adult endothelial cells adhere most effectively to prosthetic surfaces precoated with CIG or gelatin, and remain attached following exposure to shear forces.

Elastosis in breast carcinoma: II. Association of protease inhibitors with immature elastic fibres

The elastosis of 11 invasive ductal and infiltrative lobular carcinomas of the breast was specifically immunostained for the plasma protease inhibitors alpha-1 antitrypsin, alpha-1 antichymotrypsin, alpha-2 macroglobulin, inter alpha trypsin inhibitor and C1 esterase inhibitor. None of these components was detected in the elastic fibres of normal ducts or blood vessels in the breast. The elastosis in breast carcinomas was also stained by Concanavalin A and Triticum vulgaris lectins. Such lectin staining probably represents binding to the microfibrillar component of elastic fibres, which is increased in immature elastic fibres, thus suggesting that the elastotic fibres of breast carcinoma are recently synthesised. It is suggested that the presence of protease inhibitors may influence the metabolism of elastic fibres, facilitating elastic fibre proliferation by the inhibition of elastinolytic enzymes.

Helix pomatia and Ulex europeus lectin binding in human breast carcinoma

Formalin fixed, paraffin embedded tissue from 100 consecutive cases of breast carcinoma were studied for binding with Helix pomatia (HPA) and Ulex Europeus (UEA1) lectins. Serial sections were pretreated with trypsin or neuraminidase to determine the effect of these enzymes on lectin binding. The lectins were visualized by the peroxidase antiperoxidase technique and the cell staining proportion assessed in a semi-quantitative manner under the light microscope. Correlating staining with prognostic factors and patient follow-up details showed that UEA1 related to disease-free interval and survival, and HPA to lymph node stage, time to loco regional recurrence and to survival. Relationships with both lectins were abolished by pretreatment with neuraminidase. The study demonstrates that a simple assessment of lectin binding can provide prognostic information in breast cancer. This may be useful particularly when conservational surgical practice restricts the amount of nodal tissue for staging.

An altered lectin binding to mucus glycoprotein in goblet cells of human tracheobronchial epithelium among former mustard-gas workers

Lectins, which are well known to have an ability to bind with specific carbohydrate residues of glycoprotein, have been used to examine cellular changes associated with malignant transformation. For the analysis of mucus glycoprotein of goblet cells in the tracheobronchial epithelium, 192 paraffin-embedded sections from 54 autopsy cases including the cases with a history of mustard-gas (MG) exposure were stained with seven plant lectins using PAP method. PNA binding with no neuraminidase treatment as well as BSA-1 binding was observed most frequently in MG-exposed lung cancer cases. The proportion of cases positive for SBA binding in MG-exposed and/or lung cancer cases had a statistical difference from non-MG-exposed non-lung cancer cases. These observations may indicate a large heterogeneity in oligosaccharide chains of mucus glycoprotein and suggest its incomplete or abnormal synthesis, which is most likely to be due to previous exposure to carcinogen, such as MG.

Peroxidase-labelled lectin binding of human extravillous trophoblast

The binding of four peroxidase-conjugated lectins, concanavalin A (Con-A), wheat germ agglutinin (WGA), peanut agglutinin (PNA) and soybean agglutinin (SBA), in both fixed and frozen tissue sections of human extravillous trophoblast (EVT) was determined. On the basis of its lectin binding properties the EVT cell population was found to be heterogeneous. PNA and SBA did not bind to any of the EVT cells. Con-A and WGA bound to most EVT cells, with the exception of the trophoblast of the chorion laeve. The trophoblast giant cells bound only Con-A and not WGA. The villous cytotrophoblast, from which the EVT cells are said to derive, does not express the sugar groups detected by the above lectin probes. The expression of mannosylated and di-N-acetylchitobiosyl residues by a fetally derived cell invites speculation that such expression enables it both to invade host maternal tissues and to avoid any adverse host immunological response.

Occlusion of intra-acinar pulmonary arteries in pulmonary hypertensive congenital heart disease

Lung biopsy specimens from 10 consecutive cases of congenital heart disease and pulmonary hypertension (2 months-6.5 years) were examined by light and electron microscopy. By light microscopy, 8 cases showed a reduction in number of patent alveolar wall arteries associated with the structural features of early pulmonary vascular disease-extension of muscle, a significant increase in pulmonary arterial medial thickness (P less than 0.001) and little if any intimal proliferation (Heath & Edwards Grade I or II). In one additional child with Grade IV disease, arterial number could not be determined accurately. For all 10 cases, all blocks of tissue examined by light and electronmicroscopy showed absence of any lumen in structures identified as alveolar wall arteries by their position, shape and the presence of an external (or single) elastic lamina. In 3 additional similar cases, endothelial cells of narrowed and occluded arteries were marked by labelling with the lectin Ulex europaeus. Occluded arteries were identified consisting of mature smooth muscle cells and remnants of degenerating endothelial cells. Occlusion of alveolar wall arteries appears to be an early event in the development of pulmonary vascular disease, is associated with differentiation of smooth muscle cells in normally thin walled precapillary arteries and precedes significant obliterative intimal changes in more proximal vessels.

Lectin histochemistry of galactose and N-acetyl-galactosamine glycoconjugates in normal gastric mucosa and gastric cancer and the relationship with ABO and secretor status

The histochemical binding of four lectin-peroxidase conjugates to normal human gastric mucosa and gastric carcinoma is described. The lectins were peanut agglutinin (PNA) which is specific for galactose residues and soy bean agglutinin (SBA), Dolichos biflorus agglutinin (DBA) and Helix pomatia agglutinin (HPA) which are specific for N-acetylgalactosamine. Binding of PNA to surface mucous cells or normal gastric mucosa occurred in non-secretors but not secretors and was independent of ABO blood group at all sites. PNA binding was unrelated to the immunohistochemical demonstration of Thomsen-Friedenreich (T) antigen. DBA and HPA bound selectively to surface mucous cells in normal gastric mucosa from group A secretors but binding at other sites was independent of ABO status. SBA binding showed no relationship with blood group or secretor status. In gastric cancers the major finding was the occurrence of extensive masking of lectin binding sites by sialic acid which was not seen in normal mucosa. Sialic acid masking was most marked with PNA and least marked with DBA. There was no correlation between lectin binding patterns and the stage or differentiation of tumours. Results are consistent with in vitro studies demonstrating increased sialation of membrane glycoproteins following malignant transformation. Difficulties in interpreting the histochemical demonstration of lectin binding in terms of specific glycoconjugates are discussed.

Cervical intraepithelial glandular neoplasia (adenocarcinoma in situ and glandular dysplasia). A correlative study of 23 cases with histologic grading, histochemical analysis of mucins, and immunohistochemical determination of the affinity for four lectins

Twenty-three cases of cervical intraepithelial glandular neoplasia (CIGN)--a term encompassing adenocarcinoma in situ and glandular dysplasia of the uterine cervix--were studied histologically, histochemically for mucins (neutral mucins, sialomucins and sulfomucins), and immunohistochemically for the affinity of four lectins (WGA, PNA, RCA, UEA). For comparison, six cases of cervical invasive adenocarcinoma and ten cases of cervices without tumor were similarly studied. Criteria for histologic grading of CIGN into three degrees were proposed according to the hyperchromasia and the stratification of nuclei, number of mitoses, and amount of intracellular mucin. Two different types of CIGN were distinguished according to their histological aspect and their mucin pattern: CIGN type A, where the mucin pattern was qualitatively similar to that of normal endocervical mucosa, i.e., neutral mucins, sulfomucins and sialomucins; and CIGN type B, where the glandular cells resembled small intestinal goblet cells and the mucins consisted of neutral mucins and sialomucins with the absence of sulfomucins. Nine cases of CIGN were of type A, 2 of type B, and 12 of both type A and B. Differences in lectin binding existed between normal columnar cells, CIGN, and invasive adenocarcinomas, as well as between CIGN of type A and B. The intensity of the positive immunochemical reaction varied, as well as the type of binded lectin and its localization in the cell. There was a great heterogeneity in the same histologic group from one case to another, and even in the same case from one cell to another.

Changes in lectin binding patterns in the developing pulmonary vasculature of the pig lung

Lectin binding patterns to the developing pulmonary vasculature were studied in 10 Large White pigs aged 1 min to 1 week and in three adult animals. Paraffin-embedded tissue sections were exposed to eight lectin peroxidase conjugates: Dolichos biflorus, Triticum vulgaris, Concanavalin A, Ricinus communis type 2, Arachis hypogaea, Ricinus communis type 1, Tetragonolobus purpureas and Ulex europeus. Lectin binding patterns to the pulmonary arterial and venous endothelium, to smooth muscle cells (SMCs) and to the arterial connective tissue were age-related. Changes occurred during the first week of life and between 1 week and adult life. Neither the endothelial binding patterns in the adult nor the SMC patterns in the immature and adult lung conformed to known morphological differences between the different segments of the arterial and venous pathways. Heterogeneity for endothelial binding was seen in the immature lung. These studies indicate biochemical differences in surface structure between the endothelium, SMCs and connective tissue of the immature and mature lung. Ultrastructural localization of the lectins in the vasculature of the developing animal lung ought to help interpret similar data obtained on the vessels of the immature human pulmonary hypertensive lung using lectins which show similar binding patterns in both species.

The utilization of [3H] sugars by non-malignant and malignant human breast

The utilization of [3H] sugars and leucine by non-malignant and malignant human breast has been assessed using an organ culture technique with subsequent tissue autoradiography. The uptake of sugars by normal and hyperplastic breast was generally constant, with some differences observed in the utilization of galactose by acini of normal and hyperplastic tissues. After 24 h incubation localization was predominantly at the luminal cell periphery. The utilization of sugars by carcinomas was much more variable. Differences were observed between adjacent cells and cell groups of the same tumour. The uptake of individual sugars within a carcinoma was also varied being either similar to, or greater or lesser than normal breast. Variation between carcinomas was also present. No correlation between type and differentiation was noted in this respect, but there was between localization of sugars and differentiation. Better differentiated areas in tumours showed patterns similar to non-malignant breast whilst localization in poorly differentiated cell groups was cytoplasmic. The uptake of leucine was more constant and proved to be a useful indicator of viability. While this approach cannot give information with regard to differences in glycoprotein structure between non-malignant and malignant breast, it has been of value in determining the heterogeneity of tumour cells with regard to the enzymes involved in glycosylation. As such it would be of use in assessing the uniformity of response to agents modifying glycosylation.

Lectin binding and steroid receptors in human breast carcinomas

A series of breast carcinomas of known steroid receptor status have been examined for evidence of binding of the lectins peanut agglutinin, soy bean agglutinin and wheat germ agglutinin. Correlations were found between oestrogen receptor status and reactivity of carcinomas to peanut agglutinin and soy bean agglutinin but these were not absolute. Wheat germ agglutinin binding was unrelated to the presence of oestrogen receptors. No relationship was evident between progestogen receptors and the binding of any lectin. It therefore seems unlikely that lectin histochemistry can replace steroid receptors as markers of hormone dependence in breast carcinomas.

The binding of peroxidase-labelled lectins to human breast epithelium. IV--The reactivity of breast carcinomas to peanut, soy bean and Dolichos biflorus agglutinins

The binding of the lectins from peanut, soy bean and Dolichos biflorus (specific for galactose and/or N-acetyl-D-galactosamine), to human breast carcinomas has been investigated. In contrast to the consistent pattern found in normal breast the reactivity of carcinomas to peanut lectin is varied, the most striking differences being prominent binding without desialation in some tumours and virtual lack of reactivity in others. There tends to be a greater degree of binding of soy bean agglutinin to carcinomas than normal although this is not absolute, and the reverse applies to Dolichos biflorus agglutinin. Comparison of the binding of the three lectins has revealed a complex heterogeneity of the carbohydrate chains within individual tumours and between different carcinomas. A significant relationship between peanut lectin binding, with the use of neuraminidase, and tumour differentiation as been found, and to a lesser extent with soy bean agglutinin when desialation is performed. However, the pattern of reactivity of the carcinomas with these three lectins does not appear to be related to local lymph node metastasis.

Lectin binding in human skeletal muscle: a comparison of 15 different lectins

Fifteen lectin-horseradish peroxidase conjugates have been used in a comprehensive histochemical study of human skeletal muscle. The staining patterns of many lectins were found to be coincident with the known distributions of types I, III, IV and V collagen, fibronectin and laminin. One lectin, Bandeiraea simplicifolia (BSA I), selectively stained capillaries in a blood group-specific manner, the significance of which is unknown. The results show that although lectins are useful cytochemical probes for identifying tissue glycoconjugates, lectin binding is not solely determined by monosaccharide specificity as lectins which interact with the same sugars may have completely different staining patterns. Factors such as accessibility, glycan conformation and oligosaccharide sequence also affect lectin binding in tissues. For these reasons, we conclude that a comprehensive histochemical investigation of tissue glycoconjugates should employ a large number of lectins, preferably with overlapping sugar specificities.

The binding of peroxidase-labelled lectins to human breast epithelium. III--Altered fucose-binding patterns of breast carcinomas and their significance

Tissue sections from 80 human breast carcinomas have been examined for evidence of binding of the two fucose-specific lectins, Lotus tetragonolobus and Ulex europeus I, with enzymes utilized as an indicator system. Both single-staining and double-staining methods (Lotus tetragonolobus-peroxidase and Ulex europeus I-alkaline phosphatase) have been employed. In contrast to normal breast in which there is consistent reactivity of all epithelium with Lotus tetragonologus a variable loss of binding has been found within carcinomas. Surprisingly, this bears no relationship to tumour differentiation; nor does it correlate with local lymph node metastasis. Ulex europeus I has a variable reactivity with carcinomas, as it does with normal breast epithelium, and this likewise has no correlation with differentiation. However, a relationship has been found between specific patterns of binding and axillary lymph node status. The value of using two lectins with the same major sugar specificity but having different binding affinities is illustrated in this study, in which differences in behavioural characteristics have been identified between fucose-containing glyco-conjugates having minor structural variations.

The binding of peroxidase-labelled lectins to human breast epithelium. II—the reactivity of breast carcinomas to wheat germ agglutinin

The binding of peroxidase-labelled wheat germ agglutinin (WGA) to a series of 125 human breast carcinomas has been studied. Routine fixation and processing has been shown to have no deleterious effect on reactivity. In contrast to the homogeneous binding of WGA to normal and hyperplastic human breast previously reported, the binding of WGA to breast carcinomas exhibits heterogeneity. This is of two forms: (1) in relation to cell reactivity, which is significantly correlated to tumour differentiation, with fewer cells reacting in those carcinomas showing loss of histological differentiation; (2) with regard to the interaction between WGA and specific saccharides of cellular glycan-components, binding to sialic acid appearing to be of significance to varying degrees in some carcinomas but not in others nor, as previously reported, in normal breast. The alteration in WGA-saccharide interaction is an indicator of the heterogeneity of the carbohydrate chains of glycoproteins within neoplastic cells of the same tumour and between carcinomas. The other finding of note has been that of the significant association between heterogeneity of cellular reactivity to WGA and the presence of axillary lymph node metastasis, but a lack of correlation between virtual absence of reactivity and nodal metastasis.