Ulex europeus I--peroxidase as a marker of vascular endothelium: its application in routine histopathology

Bone marrow hypervascularity in patients with myelofibrosis identified by infra-red thermography

Infra-red thermography was used to assess bone marrow vascularity in six patients with myelofibrosis secondary to myeloproliferative disorders (four primary myelofibrosis and two primary proliferative polycythaemia). The technique was evaluated with conventional static and dynamic radio-isotopic imaging and with immunohistochemical staining of bone marrow biopsies. Infra-red thermography identified increased bone marrow blood flow in patients with established myelofibrosis and correlated with dynamic radio-isotopic studies of blood flow and hypervascularity identified by immunohistochemistry. Increased bone marrow blood flow and vascular proliferation was not confined to the central bone marrow but also extended into the peripheral marrow of the long bones. Endothelial cell proliferation may be an initiating event in the pathogenesis of myelofibrosis but evaluation of bone marrow vascularity and blood flow has hitherto relied on invasive and complicated techniques. This study has identified bone marrow hypervascularity in patients with myelofibrosis and shown infra-red thermography to be a simple non-invasive method of assessing vascularity. This non-invasive technique may be used to study disease progression and response to therapeutic regimens in patients with myelofibrosis and to study bone marrow blood flow in other bone marrow disorders.

Lymphangiogenesis in the bone-implant interface of orthopedic implants: importance and consequence

The lymphatic system plays an essential physiological role in homeostasis, interstitial fluid composition, and immunity while impaired lymphatic function has been implicated in a number of pathological conditions, including arthritis and delayed wound healing. This study investigated lymphatic capillary growth and lymphangiogenesis pathways in the bone-implant interface from patients with aseptically loosened prosthetic joints. The newly developed lymphatic specific marker, podoplanin, has enabled the first demonstration of lymphatic capillaries in peri-prosthetic tissues (60% of cases contained podoplanin positive vessels). The pro-lymphangiogenic factor (VEGF-C) and its receptor VEGFR-3 showed high level of expression in these tissues, (often in areas of high levels of wear debris). However despite the upregulation of the lymphangiogenesis pathway by a VEGF-C/VEGFR-3-mediated mechanism, there were relatively few podoplanin positive lymphatic vessels in the bone-implant interface (3.4% of total vessels). This may have important pathological consequences in terms of perpetuating inflammation and edema by inhibiting the removal of macromolecules, cells, and interstitial fluid. The identification of lymphatic vessels with internalized polyethylene wear particles provides evidence of this route of wear debris transportation to distal sites. This paper highlights the importance of lymphatic vessels in the maintenance of local and distal inflammatory responses to prosthetic wear particles.

Cutaneous lymphangiosarcoma in a young dog: clinical, anatomopathological and lectinhistochemical description

Lymphangiosarcoma is a rare tumour in domestic animals arising from lymphatic endothelial cells. Occasionally, microscopic differentiation with haemangiosarcoma may be difficult. The aim of the present study was to describe a lymphangiosarcoma in a 1-year-old female Doberman Pinscher dog and to characterize its lectinhistochemical binding pattern as compared with that of haemangiosarcoma. The dog was presented because of a cutaneous painful swelling located in the left axilla. Histological diagnosis confirmed lymphangiosarcoma. The dog was killed. Necropsy revealed mediastinal lymph nodes' involvement. Twenty lectins were tested in tissue sections of this case as well as in four haemangiosarcomas from other dogs. Staining intensity was issued upon optical density determinations. Percentage of lectinhistochemical staining area was also conducted. RCA-I showed the most intense and wide distributed labelling pattern for lymphangiosarcoma. PHA-E was the counterpart for haemangiosarcoma. Should similar results be obtained in further studies, such differences could aid in the differential diagnosis between lymphangiosarcoma and haemangiosarcoma when histological pictures were not conclusive.

Markers for the lymphatic endothelium: in search of the holy grail?

The ability to discriminate reliably at the histological level between blood and lymphatic microcapillaries would greatly assist the study of a number of biological and pathological questions and may also be of clinical utility. A structure-function comparison of these types of microcapillary suggests that differences which could function as markers to allow discrimination between blood and lymphatic endothelium should exist. Indeed, to date a variety of such markers have been proposed, including basement membrane components, constituents of junctional complexes such as desmoplakin and enzymes such as 5'-nucleotidase. Additionally, a variety of cell surface molecules are thought to be differentially expressed, including PAL-E, VEGFR-3, podoplanin, and LYVE-1. Several of the lymphatic markers proposed in the literature require further characterization to demonstrate fully their lymphatic specificity and some have proven not to be reliable. The relative merits and drawbacks of each of the proposed markers is discussed.

An IgG monoclonal antibody against Dictyostelium discoideum glycoproteins specifically recognizes Fucalpha1,6GlcNAcbeta in the core of N-linked glycans. Localized expression of core-fucosylated glycoconjugates in human tissues

Core fucosylation of N-linked oligosaccharides (GlcNAcbeta1, 4(Fucalpha1,6)GlcNAcbeta1-Asn) is a common modification in animal glycans, but little is known about the distribution of core-fucosylated glycoproteins in mammalian tissues. Two monoclonal antibodies, CAB2 and CAB4, previously raised against carbohydrate epitopes of Dictyostelium discoideum glycoproteins (Crandall, I. E. and Newell, P. C. (1989) Development 107, 87-94), specifically recognize fucose residues in alpha1,6-linkage to the asparagine-bound GlcNAc of N-linked oligosaccharides. These IgG3 antibodies do not cross-react with glycoproteins containing alpha-fucoses in other linkages commonly seen in N- or O-linked sugar chains. CAB4 recognizes core alpha1,6 fucose regardless of terminal sugars, branching pattern, sialic acid linkage, or polylactosamine substitution. This contrasts to lentil and pea lectins that recognize a similar epitope in only a subset of these structures. Additional GlcNAc residues found in the core of N-glycans from dominant Chinese hamster ovary cell mutants LEC14 and LEC18 progressively decrease binding. These antibodies show that many proteins in human tissues are core-fucosylated, but their expression is localized to skin keratinocytes, vascular and visceral smooth muscle cells, epithelia, and some extracellular matrix-like material surrounding subpopulations of lymphocytes. The availability of these antibodies now allows for an extended investigation of core fucose epitope expression in development and malignancy and in genetically manipulated mice.

The early stages of the repair of adult human diaphyseal fractures

Periosteum was obtained within 10 days of injury from the site of 17 adult tibial diaphyseal fractures during internal fixation. Osteogenic cells, non-osteogenic cells and vascular elements were identified in situ using a variety of techniques. In all cases, the periosteum was thickened with randomly distributed plaques of cartilage and bone. Cells covering newly formed bone trabeculae expressed osteocalcin. Lectin-binding revealed high vascularity. Few mast cells were observed. Macrophages and acid phosphatase positive cells, some multinucleate, were observed in abundance. These findings suggest that the repair of the adult human diaphyseal fracture is similar to that of experimental fractures in rapidity of onset, high vascularity and in bone and cartilage formation. They differ in the fact that chondrogenesis and osteogenesis appear to be simultaneous in human fractures but sequential in experimental fractures. The paucity of mast cells suggests that they probably play no significant role in the repair of the human fractures.

Human capillary endothelial cells from abdominal wall adipose tissue: isolation using an anti-pecam antibody

We have developed a novel isolation technique for harvesting human capillary endothelial cells. We compared the use of either Ulex Europaeus Agglutinin (UEA) lectin or anti-platelet endothelial cell adhesion molecule (PECAM) antibody conjugated to magnetic beads for the ability to isolate and maintain pure cultures of human capillary endothelial cells. Cells isolated using either method actively scavenged DiI-acetylated-low density lipoprotein and expressed von Willebrand factor (vWf) up to four passages as assessed by immunofluorescent labeling. Endothelial cells isolated using the anti-PECAM antibody method maintained these endothelial-specific properties for up to 12 passages while the percentage of UEA selected cells expressing these properties decreased during increasing passage number. Furthermore, while both techniques yielded cells that bind UEA at Passage six, only the antibody selected cells expressed the normal pattern of endothelial-specific cellular adhesion molecules as assessed by flow cytometry. Both cell isolates were cultured within a three-dimensional matrix of type I collagen, the antibody selected cells formed tubelike structures within 2 days, while the lectin selected cells did not. The antibody selected capillary endothelial cells were transduced with a retroviral vector containing the human growth hormone cDNA and were found to secrete growth hormone from both two- and three-dimensional cultures. We propose that anti-PECAM antibodies linked to a solid support provide a highly selective step in the isolation and maintenance of pure populations of human capillary endothelial cells from abdominal wall liposuction remnants.

Human microvessel endothelial cells: isolation, culture and characterization

Over recent years, interest in endothelial cell biology has increased dramatically with our ability to grow and study endothelial cells in vitro. While large veins and arteries remain a quick and convenient source of endothelial cells, the great morphological, biochemical and functional heterogeneity that endothelial cells express has necessitated the development of techniques to isolate microvessel endothelial cells from different tissues to create more realistic in vitro models. The majority of isolation procedures employ selective methods to enrich microvessel endothelial cells from tissue homogenates directly, or after a period in culture. These include sieving/filtration, manual weeding, isopycnic centrifugation, selective growth media, and the use of flow cytometry or magnetic beads coupled with specific endothelial cell markers. The establishment of pure endothelial cell populations is important for studying their biochemistry and physiology and there are many morphological, immunological and biochemical criteria which can be used to characterize human endothelial cells. These range from classical markers such as von Willebrand Factor and angiotensin-converting enzyme to novel markers like platelet endothelial cell adhesion molecule-1 (CD31) and the expression of E-selectin on cytokine-activated endothelial cells.

Isolation and characterization of microvessel endothelial cells from human mammary adipose tissue

A method for the isolation and long-term culture of human microvessel endothelial cells from mammary adipose tissue (HuMMEC) obtained at breast reduction surgery has been developed. Pure cultures of HuMMEC were isolated by sequential digestion of the fat with collagenase and trypsin followed by specific selection of microvessel fragments with Ulex europaeus agglutinin-1 coated magnetic beads (Dynabeads). The resulting cells formed contact-inhibited monolayers on gelatin and fibronectin substrates and capillary-like "tubes" on Matrigel; they also expressed von Willebrand factor, angiotensin-converting enzyme, and accumulated acetylated low density lipoprotein. Further immunofluorescence characterization revealed the presence of antigens for the endothelial cell specific monoclonal antibodies EN4 and H4-7/33. In addition, the origin of these cells was confirmed by the demonstration of the cell adhesion molecules, platelet endothelial cell adhesion molecule-1 (CD31), and endothelial leukocyte adhesion molecule-1 (ELAM-1/E-selectin) upon stimulation with tumor necrosis factor (TNF) alpha. HuMMEC were found to express-1 ELAM-1 at lower levels of TNF alpha (< 10 ng/ml) than required by human umbilical vein endothelial cells. These cells should provide a useful in vitro model for studying various aspects of microvascular biology and pathology.

Kaposi's sarcoma: a review of gene expression and ultrastructure of KS spindle cells in vivo

The ultrastructural features and the gene expression pattern of Kaposi's sarcoma (KS) spindle cells in vivo suggest that KS is a tumor of the mixed cell type. The expression pattern of cytokines and cytokine receptors in the tumor lesion, together with the results obtained from in vitro characterization of KS-derived cells, provide evidence that paracrine mechanisms of growth factor action are important for the maintenance of KS. The reports on virus infection of KS cells suggest an indirect role of virus infection in the induction of KS, most likely mediated by immunostimulation and subsequent production of cytokines.

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.

[The heterogenicity of the vascular endothelium]

The vascular endothelium has long been considered to be a homogeneous cell type. It is only recently that its remarkable heterogeneity has been shown. The selective and organ-specific adhesion of cells of the immune system, of metastasizing tumor cells and of microorganisms underscores the central position of the endothelium between the circulation and each organ. The use of antibodies and lectins led to the recognition of species-, organ-, and age-specific endothelial cell surface receptors. Identification of the endothelial adhesion molecules and -mechanisms, which are part of the "endothelial organ- and tissue address" would lead to the possibility of blocking the adhesion of cells, such as e.g. tumor cells.

Organ-derived microvessel endothelial cells exhibit differential responsiveness to thrombin and other growth factors

To investigate the relationship between endothelial cells and organ-associated vascular physiology, microvascular endothelial cells were isolated from murine brain, lung, and liver tissues. During culture, these endothelial cells maintained certain differentiated characteristics common to all endothelial cells, but also showed organ-specific characteristics, with distinct patterns of responsiveness to various growth factors. Microvascular endothelial cells from all organs responded to endothelial cell growth factor (ECGF), but lung (LE-1) and brain (MBE-12) endothelial cells showed different responsiveness to thrombin (10-60 nM), combinations of thrombin and ECGF, or thrombin and extracellular matrix. Liver sinusoidal endothelial cells (HSE) were relatively unresponsive to thrombin, but were the most responsive of the endothelial cells to EGF. Endothelial cells isolated from lung and brain, where fluxes in vascular permeability are observed following injury, showed dramatic morphological alterations in response to nanomolar concentrations of thrombin. These cells also exhibited the highest amount of 125I-thrombin binding at these concentrations. Scatchard analysis of 125I-thrombin binding indicated that LE cells have the highest affinity for thrombin, followed by MBE, with HSE exhibiting significantly lower affinity. The binding of 125I-thrombin to these cells was inhibited by the TR-9 monoclonal antibody directed against fibroblast high-affinity thrombin receptors involved in thrombin-stimulated mitogenesis. The results suggest that the differences in growth stimulation observed between organ-derived endothelial cells in response to thrombin, ECGF, and EGF may relate to differential expression of receptors for these factors. These observations demonstrate yet another aspect of the functional heterogeneity of the microvascular endothelium.

Immunocytochemistry of eruptive haemangiomas (pyogenic granulomas)

Eight eruptive haemangiomas (pyogenic granulomas) were stained immunocytochemically. Many of the cells reacted with markers for endothelial cells. The reactions with anti-vWF antibody were weaker than those with UEA-I-lectin and with the monoclonal antibody BMA 120. These results probably reflect reduced capability for storage of vWF by proliferating endothelial cells. Many cells were negative for endothelial-cell markers, and they reacted with a monoclonal antibody against muscle actin. These cells may be myofibroblasts and pericytes. The studies indicate that eruptive haemangiomas are composed of pericytes, myofibroblasts and endothelial cells.

Carbohydrate analysis of human von Willebrand factor with horseradish peroxidase-conjugated lectins

Human von Willebrand factor (vWF) immobilized on a polyvinylidene difluoride membrane was subjected to binding assay with a series of horseradish peroxidase-conjugated lectins. The protein was reactive with concanavalin A, Ricinus communis agglutinin 120, wheat germ agglutinin and Ulex europaeus agglutinin I (UEA-I) but not with peanut agglutinin before sialidase treatment. These reactivities were consistent with the major oligosaccharide structure reported except for UEA-I. The reactivity with UEA-I was greatly decreased after digestion of the protein with either alpha-L-fucosidase or peptide-N-glycosidase F, but no significant decrease was observed after mild alkaline treatment or delipidation. vWF and UEA-I have been independently used as a good marker for human endothelial cells. Our results indicate that vWF itself contains UEA-I reactive sugar chains in its Asn-linked oligosaccharides.

Naevocytic naevi with vascular-like spaces

Fourteen cases of naevocytic naevi with anastomising lacunae suggestive of vascular spaces are reported. The cells lining these lacunae were consistent with naevus cells, being positive for vimentin and S100 protein and negative for factor VIII-related antigen and Ulex europaeus I. The cells were not surrounded by laminin or type IV collagen. We suggest the formation of these vascular-like spaces may be due to defective production or increased degradation of components of the basement membrane with a consequent lack of cohesion.

Post cricoid lymphangioma

A 69-year-old female patient presented with symptoms characteristic of globus pharyngeus and barium swallow examination was normal. Her symptoms persisted and pharyngoscopy was undertaken; a post-cricoid polyp was found and removed. Histological examination revealed this to be a lymphangioma. Histological appearances, pathogenesis and treatment are discussed. The case illustrates that persisting symptoms presenting as globus pharyngeus should be further investigated to exclude rare lesions.

A light microscopical, immunohistochemical, and ultrastructural comparison of hemangiomata and lymphangiomata

In this study we have compared the light microscopical, immunohistochemical, and ultrastructural features of five hemangiomata of the dermis with five lymphangiomata of the dermis and subcutaneous tissue. We have attempted to define differentiating features with regard to the ultrastructural appearances and the immunohistochemical staining for the endothelial markers factor VIII-related antigen (FVIII:RAg) and Ulex europaeus agglutinin I (UEA-I). In addition, immunolocalization of FVIII:RAg at the ultrastructural level was performed to compare its distribution within endothelial cells of neoplastic blood vessels and lymphatic vessels. The results show that immunohistochemical staining for FVIII:RAg and UEA-I does not differentiate between blood and lymphatic vessels. However, the presence of a fragmented basal lamina and anchoring filaments does distinguish lymphatic vessels from blood vessels ultrastructurally.

Irradiation-induced penile angiosarcoma

We report a case of angiosarcoma of the glans penis in a 77 year old male Caucasian. The tumour developed 18 years after a course of radiotherapy for a penile ulcer which was an intra-epidermal squamous carcinoma. The differential diagnosis and the concept of radiotherapy-induced angiosarcomas are discussed.

Lectin histochemistry in brains with juvenile form of neuronal ceroid-lipofuscinosis (Batten disease)

Defective utilization of dolichols in the synthesis of glycoprotein leads to an accumulation of the storage, pigment "ceroid" lipofuscin, containing high-mannose-type glycoconjugates, in brains affected by neuronal ceroid-lipofuscinoses (NCL). We have employed lectin histochemistry to study the distribution of such compounds and the composition of other glycoconjugates in brains of patients with a juvenile form of the disease (JNCL). Concanavalin A detected the high-mannose glycoconjugates in all neurons of brains with JNCL, in lipofuscin-containing neurons of aging brains and in some neurons of age-matched control brains. Three other lectins (soybean agglutinin, Peanut agglutinin and Ulex europaeus agglutinin-I) recognized sugar moieties in neurons containing lipofuscin in patients only with JNCL and not in age-matched or aging brains. The results led to the conclusion, that the binding pattern of these three lectins may differentiate between storage materials of NCL and aging brains.

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.

Microvascular endothelial cell heterogeneity: interactions with leukocytes and tumor cells

Endothelium constitutes a highly specialized organ that lines the vascular system and lymphatic channels. This organ is a complex network of arteries, veins, and microvessels that differ in size, structure, and function. The unique and strategic location imposes functional demands on the endothelium that are far greater than just being a passive barrier. Endothelial cells have the ability to differentiate both in structure and function in response to the needs of diverse tissue environments, making this organ extremely heterogeneous. Although vascular endothelial cells share certain common properties, they differ in regard to structure, antigenic and cell surface determinants, adhesion molecules, and metabolic function. The unique cell surface profiles expressed by endothelial cells in different tissue locations can be recognized by specific populations of circulating leukocytes or tumor cells, which contribute to their arrest and invasion patterns. This article attempts to review our current understanding of endothelial cell heterogeneity and its significance to patterns of leukocyte and tumor cell trafficking.

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.

Subinvolution of the uteroplacental arteries in the human placental bed

Subinvolution of the uteroplacental arteries of the placental bed is a recognized cause of post partum haemorrhage causing significant morbidity. Whilst the physiological changes in these arteries during pregnancy and the part played by endovascular trophoblast migration are well documented, the sequence of events during involution and the pathophysiology of subinvolution are unknown. Using immunohistochemical techniques we have studied uteroplacental arteries in the placental bed in 25 cases of post partum haemorrhage and compared the subinvoluted vessels with normally involuted vessels. Non-involuted vessels were present in 22 test cases; these abnormal vessels were filled with thrombus and no endothelial lining was detected. Extravillous perivascular trophoblast was usually present in the walls of these abnormal vessels and in some cases was seen in an endovascular position. Subinvolution of placental site vessels may represent an abnormal interaction between maternal uterine cells and fetal trophoblast.

Histogenesis of Kaposi's sarcoma and angiosarcoma of the face and the scalp

This study reviews data on the histogenesis of Kaposi's sarcoma and angiosarcoma derived from clinical features, histology, electron microscopy, enzyme histochemistry, and immunochemistry of both diseases. Their hemorrhagic clinical appearance contrasts the predominantly lymphatic histologic features of vessels in early lesions. Investigations performed to resolve the debate whether these tumors arise from blood vessel or lymphatic endothelium show remarkably similar results for both conditions. Electron microscopy reveals Weibel - Palade bodies in a minority of cases, but features consistent with less well-differentiated blood vessel endothelium may be seen in a greater proportion of tumors. Enzyme histochemistry generally shows absence of adenosine triphosphatase and alkaline phosphatase in tumor cells; a pattern of enzymes similar to that found in normal lymphatic endothelium. Conflicting data arises from the large number of immunohistochemical studies performed on both conditions. Factor VIII-related antigen and Ulex europaeus agglutinin-I have been most frequently employed, but the specificity of these agents for blood vessel endothelium is debatable. Panendothelial markers show consistent labeling of both tumors, but marker studies employing a wide range of monoclonal antibodies specific for blood vessel endothelium have shown occasional positive labeling of tumor cells. A number of studies have claimed absence of labeling with specific blood vessel monoclonal antibodies, but at present no study employing a specific marker for lymphatic endothelium has been reported. Although the demonstration of specific markers for blood vessel endothelium in these tumors has been variable, the data would be compatible with lesions arising from undifferentiated stem cells that proliferate with varying degrees of differentiation toward blood vessel endothelium. An alternative hypothesis for the histogenesis of Kaposi's sarcoma would be one of multicentric hyperplasia containing lymphatic venular anastamoses with elements of both lymphatic and blood vessel endothelium.

Endometrial stromal sarcoma of low-grade malignancy. Immunohistochemical and three-dimensional reconstruction study with special emphasis on the inadequate terminology of endolymphatic stromal myosis

We report two cases of endometrial stromal sarcoma of low-grade malignancy (so-called endolymphatic stromal myosis) with special emphasis on the histogenesis and mode of invasion. The microscopic and immunohistochemical features of the tumor cells resembled those of endometrial stromal cells. A three-dimensional reconstruction study of the tumor disclosed that it grew by forming a horn- or crown-like structure between and along the vessels. The tumor then protruded into the vascular lumina with a covering of endothelial cells. Immunohistochemical study showed that the vascular system was not lymphatic but venous. We therefore think that "endolymphatic stromal myosis" is a misnomer.

Immunohistochemical differentiation between lymphangiographically verified lymphatic vessels and blood vessels

In order to investigate the antigen profile in human lymphatic vessels when compared with blood vessels, postmortem retrograde lymphangiography was done via the thoracic duct on six patients. Formalin fixed, paraffin embedded tissue was stained immunohistochemically for Factor VIII-Related antigen (F VIII R:Ag), with Ulex Europaeus 1 lectin (UEA-1) and for laminin. The results show that the endothelium of blood vessels and lymphatics at all levels of the lymphatic system react positively following staining for Factor VIII-R:Ag and with UEA-1 lectin. The staining for F VIII R:Ag was generally weaker in the endothelial cells lining lymphatic vessels. Staining for the basement membrane component laminin can be used to distinguish lymphatic capillaries and smaller lymphatic collecting vessels from blood vessels.

Angiogenic properties of Kaposi's sarcoma-derived cells after long-term culture in vitro

Cells derived from lung biopsies and pleural effusions from AIDS patients with Kaposi's sarcoma (KS) of the lungs were established in long-term culture with the aid of conditioned medium from HTLV-II-transformed T cells (HTLV-II CM). These AIDS-KS cells were similar to the so-called spindle cells in KS lesions and had some of their features. They produced factors that supported their own growth (autocrine) and the growth of other cells (paracrine), including umbilical vein endothelium and fibroblasts. That the AIDS-KS cells also expressed potent angiogenic activity was demonstrated by the chorioallantoic membrane assay and by subcutaneous inoculation of AIDS-KS cells into nude mice, which resulted in the development of angiogenic lesions composed of mouse cells and showing histological features similar to those of human KS lesions. These data suggest that AIDS-associated KS and possibly other types of KS may be initiated by signals that induce the growth of particular cells (spindle cells of lymphatic or vascular origin) and the expression of autocrine and paracrine activities.

Malignant haemangiopericytomas and haemangioendotheliosarcomas: an immunohistochemical study

Formalin-fixed, paraffin-embedded material from 15 haemangioendotheliosarcomas and eight malignant haemangiopericytomas was stained with an immunohistochemical technique for the presence of factor VIII-related antigen (F VIII-RAg), actin, laminin and for reactivity with the lectin Ulex europaeus I (UEA-I). Haemangioendotheliosarcomas stained with both F VIII-RAg and UEA-1; however, UEA-I was found to be the more sensitive of the two, reacting also with the poorly differentiated tumours. Haemangiopericytomas reacted negatively with UEA-I; surprisingly, some of these tumours exhibited a weak positivity in staining for F VIII-RAg, possibly supporting the theory about intermediate forms between haemangioendotheliosarcomas and haemangiopericytomas. Laminin was found in most of the haemangioendotheliosarcomas and was useful in illustrating their vascular growth pattern. Haemangiopericytomas also reacted positively for laminin, but the intensity of staining was less pronounced. Positive staining for actin was demonstrated in both tumour types.

Benign cystic mesothelioma of the peritoneum: immunohistochemical and ultrastructural features in a child

Benign cystic mesothelioma of the peritoneum is a well-defined but rare entity. A total of 35 instances have been reported, almost all in adults, the majority females. Cystic mesotheliomas have, until recently, been labeled cystic lymphangiomas or lymphohemangiomas. We report the case of a 14-year-old boy who, despite only subtotal resection of his abdominal mass, is well and recurrence free 9 months after surgery. The role of immunohistochemistry and electron microscopy in diagnosis is emphasized.

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.

Vascularization of the embryonic kidney. Detection of endothelial cells with Ulex europaeus I lectin

Frozen sections of human fetal kidneys were studied for the appearance of vascular elements to the developing glomeruli using Ulex europaeus (UEA-I) lectin as a marker for endothelial cells. Chains of UEA-I-positive cells, seen to extend from larger vessels, could be observed among the uninduced cells of the nephrogenic mesenchyme. During the S-shaped body stage of nephrogenesis, the cleft of the comma-shaped cluster of epithelial cells was invaded by the UEA-I-positive cells, and during further glomerular development, the UEA-I-positive cells were seen to grow in number, prior to the appearance of visible lumina to the capillaries. The present results show, in addition to revealing the vascularization pattern of developing glomeruli, that endothelial cells obtain some of their characteristic glycoconjugates during early stages of differentiation. Thus, UEA-I seems to be a valuable tool to study in detail the vascularization of various developing human tissues.

Orbital angiosarcoma with subconjunctival presentation. Report of a case and literature review

An otherwise healthy 37-year-old woman had, over the course of 2 years, a recurring subconjunctival lesion associated with blepharoptosis. Computed tomography (CT) demonstrated a large anterior and superior orbital mass. A diagnosis of angiosarcoma (AS) was made from biopsy material. The patient is alive and well 18 months after exenteration and radiation therapy. The clinical and histopathologic features of this tumor are discussed with emphasis on the differential diagnosis of malignant vascular tumors of the orbit.

Breast carcinoma with stromal multinucleated giant cells--a light microscopic, histochemical and ultrastructural study

A rare form of infiltrating ductal carcinoma of the breast containing numerous benign stromal multinucleated giant cells (MNGC) is described. Giant cell tumours of the breast are usually the result of stromal metaplasia or fusion of malignant cells or occur as extraskeletal giant cell tumours. Benign multinucleated cells in breast carcinoma, however, are a very unusual phenomenon and have been said to arise from the fusion of mononuclear cells, in response to increased vascularity. The present investigation by light and electron microscopy, in part, supports an origin for the multinucleated giant cells from mononuclear cells, but immunohistochemistry surprisingly failed to confirm this observation. Also, the formation of the multinucleated giant cells did not show any direct relationship with tumour vascularity.

A monoclonal antibody reacting with endothelial cells of budding vessels in tumors and inflammatory tissues, and non-reactive with normal adult tissues

This report describes a monoclonal antibody (MAb) generated by immunization of mice with cell suspensions of capillary-rich fragments of mammary carcinomas. The antibody (EN 7/44) belongs to the IgM class and detects a 30.5 kDa antigen which is found in the cytoplasm of human placental and umbilical vein-endothelial cells (HUVEC) and on the surface of tumor endothelium. Using indirect immunofluorescence and immunoperoxidase techniques, we did not find the MAb in peripheral blood cells or in any human cell lines tested, nor in endothelial cells from normal, nonproliferating adult tissues. Positively staining endothelium was found in the placenta, the umbilical vein and in proliferating normal tissues (intestine). Positive endothelial cells were found in acute inflammatory reactions and in tumors. In the latter, the strongest reactions were seen in newly formed budding capillaries, which were identified by their reactivity with Ulex europaeus I-lectin and antibodies against F VIII-RAG. In tumor tissues, large vessels could be positively stained with the EN 7/44 antigen, in contrast to inflammatory tissues. It is concluded that endothelial cells at the tip of a budding capillary express distinct phenotypic characteristics.

The detection of endothelial cell antigens in cutaneous tissue using methacarn and periodate lysine paraformaldehyde fixation

The use of monoclonal antibodies with endothelial cell specificity has prompted a search for methods of fixation which combine the morphology of paraffin-embedded tissue, with preservation of labile membrane antigens. Immunohistochemical staining using a variety of endothelial cell markers was compared in tissue fixed in formalin, methacarn, periodate lysine paraformaldehyde (PLP) and in frozen tissue. Whilst lectin-binding with Ulex europaeus agglutinin I (UEA) and localisation of Factor VIII-related antigen (FVIII RA) and laminin was well-visualised in methacarn-fixed and PLP-fixed tissue, fixation in PLP was necessary for the two monoclonal antibodies, PAL-E and EN4. PLP fixation has considerable potential for investigating the histogenesis of vascular tumours, particularly in Kaposi's sarcoma where frozen tissue represents a biological hazard. The normal staining pattern of human dermal vasculature is described in relation to the above endothelial cell antigens.

Histogenesis of Kaposi's sarcoma in patients with and without acquired immune deficiency syndrome (AIDS)

Immunohistochemical studies were performed in thirty skin biopsies from patients with Kaposi's sarcoma, who did and did not have the acquired immune deficiency syndrome (AIDS). Tumour histogenesis was rigorously tested using a battery of endothelial cell markers, which included two new monoclonal antibodies, EN4 and PAL E. These are both specific for endothelial cells and can be visualised in appropriately fixed paraffin embedded tissue. Whereas EN4 labels all endothelial cells, PAL E is negative in endothelium of lymphatic derivation. Lectin binding with Ulex europaeus agglutinin 1 (UEA-1) and the presence of factor VIII related antigen (FVIIIRA) and laminin were also examined. In nodular lesions of Kaposi's sarcoma the spindle cell areas were positive with EN4 and UEA-1, negative with PAL E, and showed focal staining for FVIIIRA and laminin. These results confirm that the tumour is of endothelial cell origin. Six patch stage lesions showed a network of angulated spaces, lined by cells that were positive with EN4 and UEA-1, negative with PAL E and anti-FVIIIRA, and showed only weak staining for laminin. This pattern was observed in both AIDS and non-AIDS related cases and strongly favours a lymphatic derivation for the tumour. This has important implications as it suggests that lymphatic endothelium may have special characteristics that lead to neoplastic transformation in patients with retrovirus infection.