Showing papers in "American Journal of Pathology in 1990"

PDGF and FGF stimulate wound healing in the genetically diabetic mouse.

Abstract: To examine the effects of recombinant growth factors in vivo, impaired wound healing was studied in genetically diabetic C57BL/KsJ-db/db mice Large full-thickness skin wounds made on the backs of these mice exhibited significant delays in the entry of inflammatory cells into the wound, the formation of granulation tissue, and in wound closure when compared to their nondiabetic littermates Recombinant human platelet-derived growth factor (rPDGF-BB, 1 or 10 micrograms), recombinant human basic fibroblast growth factor (rbFGF, 1 micrograms), or combinations of both were applied topically to the wounds for 5 to 14 days after wounding Diabetic mouse wounds treated with rPDGF-BB or rbFGF had many more fibroblasts and capillaries in the wound bed at 10 and 21 days than did wounds treated with the vehicle alone The animals treated with growth factors also had significantly greater wound closure at 21 days than those treated with the vehicle Combinations of rPDGF-BB and rbFGF improved all parameters of healing but not to a greater extent than either growth factor alone The effectiveness of rPDGF-BB and rbFGF suggest that recombinant growth factors may be useful in the treatment of patients with deficient wound repair

Expression of the bcl-2 oncogene protein is not specific for the 14;18 chromosomal translocation.

Abstract: It has been reported previously that the bcl-2 protooncogene protein is detectable in neoplastic cells from cases of human lymphoma in which the 14;18 chromosomal translocation is present, but not in lymphomas that lack this chromosomal rearrangement or in normal lymphoid tissue. In the present study we confirmed, by immunohistologic labeling with polyclonal and monoclonal antibodies, that bcl-2 protein is strongly expressed in many cases of follicular lymphoma and that these neoplastic follicles differ clearly from their nonmalignant counterpart (reactive germinal centres) in which bcl-2 protein is undetectable. However we also found bcl-2 protein in normal T- and B-lymphoid cells and in a variety of lymphoproliferative disorders in which the 14;18 translocation is not present. It is therefore concluded that expression of bcl-2 protein is not a specific marker for lymphomas bearing the 14;18 chromosomal translocation and that the observations of other investigators may have reflected the inadequate sensitivity of their staining procedure.

A unique phenotype of skin-associated lymphocytes in humans. Preferential expression of the HECA-452 epitope by benign and malignant T cells at cutaneous sites.

Abstract: It has been proposed that the skin is a functionally unique compartment of the immune system, although little direct evidence supporting this hypothesis has been presented. Here we show that lymphocyte populations at cutaneous sites can be differentiated from otherwise similar populations at noncutaneous sites by their preferential expression of an epitope defined by the MAb HECA-452. This MAb recognizes a predominantly 200-kd cell-surface glycoprotein present on about 16% of peripheral blood T cells, including both CD4+ and CD8+ T cells (17% and 11% HECA-452+, respectively), as well as TCR-delta-bearing T cells (32%+). Most thymocytes (99%) lacked HECA-452 antigen expression, and essentially all the HECA-452+ peripheral blood T cells were found in the adhesion molecule high, CD45R low putative memory cell subset, findings suggesting that HECA-452 expression develops peripherally as a consequence of antigenic stimulation. However, the HECA-452 antigen is not a conventional activation antigen because it was not upregulated with mitogen stimulation of peripheral blood T cells. Most significantly, among 54 diverse specimens of normal/reactive lymphoid tissues and sites of chronic inflammation, there was a clear association of lymphocyte HECA-452 expression and cutaneous location. In extracutaneous sites (n = 38) only about 5% of lymphocytes within the T-cell areas of these tissues expressed this antigen, whereas in inflammatory skin lesions (n = 16), 85% were HECA-452+. The association of HECA-452 expression and cutaneous location was also seen in a series of T-cell lymphomas. The malignant cells of 16 of 18 cases of epidermotropic (patch/plaque) stage mycosis fungoides were HECA-452+, as well as 2 of 7 nonmycosis fungoides peripheral T-cell lymphomas in skin. In contrast, this antigen was not expressed in thymic (lymphoblastic) lymphomas (n = 14), nonepidermotropic (tumor) stage mycosis fungoides (n = 5), and noncutaneous peripheral T-cell lymphomas (n = 15). Among lymphocytes, the preferential expression of the HECA-452 determinant by cutaneous T cells supports the hypothesis that the skin constitutes a immunologically unique lymphoid tissue and suggests that this molecule may play a role in either lymphocyte homing to skin or in lymphocyte interactions with the epidermis.

Cytokine-activated human endothelial cells synthesize and secrete a monocyte chemoattractant, MCP-1/JE

Abstract: We have demonstrated inducible expression of the mRNA encoding the monocyte chemoattractant MCP-1, the human homolog of the JE gene, in endothelial cells within 3 hours of treatment with IL-1 beta and tumor necrosis factor. IFN-gamma also induced expression of this mRNA after 24 hours, but to a lesser extent. MCP-1/JE protein steadily accumulated in the medium of endothelial cells during a 48-hour exposure to IL-1 beta. Medium conditioned by IL-1 beta-treated endothelial cells contained monocyte chemoattractant activity that was immunoadsorbed by anti-MCP-1 antibodies. These results suggest that endothelial cells secrete a monocyte chemoattractant, MCP-1/JE, in response to inflammatory mediators, and thus may contribute to the accumulation of monocytes at sites of inflammation.

Human abdominal aortic aneurysms. Immunophenotypic analysis suggesting an immune-mediated response.

Abstract: Cellular immunity may play a role in the pathogenesis of atherosclerosis. In this report the potential role of these cells in the formation of abdominal aortic aneurysms by immunohistochemistry was investigated. Aortic tissues from 32 patients were examined: 4 normal aortas, 6 aortas with occlusive atherosclerotic disease, 17 abdominal aortic aneurysms, and 5 inflammatory abdominal aneurysms. Using monoclonal anti-CD3 (T cells), anti-CD19 (B cells), anti-CD11c (macrophages), anti-CD4 (T helper cells), and anti-CD8 (T suppressor cells), several distinctions among these groups were found. The amount of inflammatory cell infiltrate was as follows: inflammatory aneurysms more than abdominal aortic aneurysms more than occlusive aortas more than normal aortas. CD3-positive T lymphocytes rarely were found in the adventitia of normal or occlusive aortas. In contrast, abdominal aortic aneurysms and inflammatory aneurysms exhibited most of the CD3-positive infiltrates in the adventitia. CD19-positive B lymphocytes were present mainly in the adventitia of all pathologic tissues. The CD4-positive:CD8-positive ratio was greater in abdominal aortic aneurysms and inflammatory aneurysms than in the other groups, both in the adventitia and in the media of the aortas. CD11c-positive macrophages were present throughout the diseased tissues, often surrounded by lymphoid aggregates; the greatest numbers of macrophages were found in the inflammatory aneurysm group. Our data suggests that the aneurysmal disease may progress from occlusive disease and is accompanied by an increase in chronic inflammatory cells as well as a redistribution of these cell types. Therefore it is suggested that aneurysmal disease may represent an immune-mediated event.

Intercellular adhesion molecule-1 (ICAM-1) in cellular immune reactions in the human central nervous system.

Abstract: Cryostat sections of human central nervous system (CNS) tissue samples from 10 cases of multiple sclerosis (MS), 11 cases with inflammation and necrosis, and 24 normal controls were immunostained with antibodies to intercellular adhesion molecule-1 (ICAM-1) and its integrin ligand lymphocyte function-associated molecule-1 (LFA-1). In 18 controls, small numbers of CNS microvessels were ICAM-1-positive. There were more numerous ICAM-1-positive vessels in active MS plaque edges, viral encephalitis lesions, infarcts, and in six controls. Within active MS plaques and in viral infections, mononuclear cells and some glia also were ICAM-1-positive. Mononuclear but not CNS resident cells were LFA-1-positive. Thus, CNS vessel ICAM-1 expression is variable in amount in postmortem samples of normal human CNS tissue, may increase early and focally in cellular immune reactions, and, via binding of LFA-1, may promote leukocyte influx into the CNS. Intercellular adhesion molecule-1 expression on parenchymal cells may indicate additional interactions with LFA-1 on inflammatory cells in diverse CNS lesions.

Phototoxic damage to sebaceous glands and hair follicles of mice after systemic administration of 5-aminolevulinic acid correlates with localized protoporphyrin IX fluorescence.

Abstract: The skin of albino mice given 5-aminolevulinic acid (ALA) by intraperitoneal injection rapidly developed the characteristic red fluorescence of protoporphyrin IX. Fluorescence microscopy of frozen tissue sections revealed intense red fluorescence within the sebaceous glands and a much weaker fluorescence within the epidermis and hair follicles. Little or no fluorescence was detected in the dermis, blood vessels, or cartilage of the ear. Light microscopy of skin taken at intervals after whole-body exposure of ALA-injected mice to photoactivating light revealed destruction of sebaceous cells, focal epidermal necrosis with a transient acute inflammation, and diffuse reactive changes in the keratinocytes. The dermis showed transient secondary edema and inflammation. The location and severity of the phototoxic damage correlated well with the location and intensity of the red fluorescence. The light-exposed skin appeared to recover completely except for a persistent reduction in the number of hair follicles.

Immunohistochemical distribution of type IV collagenase in normal, benign, and malignant breast tissue.

Abstract: Production of type IV collagenase by tumor cells has been linked to their metastatic potential in several experimental models A possible role for this enzyme in basement membrane type IV collagen turnover has also been suggested Two recently developed affinity-purified, monospecific antibodies directed against the amino terminus (H1), or an internal active site domain (metal binding region [MBR]) of human type IV collagenase, were employed in the avidin-biotin-immunoperoxidase technique in formalin-fixed, paraffin-embedded breast tissue samples from 55 patients Intense cytoplasmic immunostaining of myoepithelial cells was found in normal and hyperplastic tissue, and discontinuous staining was noted in intraductal carcinomas Luminal epithelial cells were negative or weakly positive in large- or medium-sized ducts but reacted frequently in normal terminal ducts and hyperplastic lesions Epithelial cells in intraductal carcinomas exhibited immunoreactivity in 20 of 23 cases Invasive carcinomas were positive in 36 of 40 cases, and metastatic cells in lymph nodes stained in 10 of 12 cases These results support a role for type IV collagenase in the basement membrane remodeling of normal breast Our findings suggest that myoepithelial cells play a pivotal role in this enzymatic activity The high percentage of positive cells in invasive carcinomas and the strong immunoreactivity of lymph node metastases support the role of the enzyme in tumor invasion and metastasis and suggest that tumor cells are the essential source of the enzyme in these processes

High prevalence of latently present cytomegalovirus in arterial walls of patients suffering from grade III atherosclerosis.

Abstract: The presence of cytomegalovirus (CMV) nucleic acids was demonstrated in arterial walls of patients with grade III and with maximally grade I atherosclerosis by dot blot and in situ DNA hybridization and by polymerase chain reaction (PCR) using probes and primers derived from immediate early (IE) and late (L) genomic regions. The presence of the complete viral genome could be demonstrated by both dot blot DNA hybridization and PCR. IE mRNA but not L mRNA could be demonstrated by in situ DNA hybridization, indicating the presence of latent CMV in the human arterial wall. By PCR 90% of the samples obtained from atherosclerotic patients were shown to contain viral nucleic acids as compared to 53% of patients with maximally grade I atherosclerosis, thus substantiating a role for this virus in the pathogenesis of atherosclerosis.

Relationship between high-grade lymphoma and low-grade B-cell mucosa-associated lymphoid tissue lymphoma (MALToma) of the stomach.

Abstract: The distinctive low-grade B-cell mucosa-associated lymphoid tissue lymphoma (MALToma) of the stomach has been well characterized in recent years, but its relationship with the more commonly occurring large B-cell gastric lymphoma has not been clarified. This study aimed to elucidate their relationship. Among 48 consecutive cases of primary malignant lymphoma found in gastrectomy specimens, there were 10 cases showing coexistence of these two elements, which were further studied in detail. The high-grade component predominated in six cases, the low-grade component predominated in two cases, and the two components were intermingled in two cases. In the low-grade component, the small neoplastic cells possessed irregular nuclei (centrocytelike), and glandular invasion was a prominent feature. In the high-grade component, the blasts occurred in clusters or sheets, and often possessed plasmacytoid cytoplasm; glandular invasion was a rare event. In both components, the neoplastic cells frequently showed formation of nodules suggestive of colonization of reactive lymphoid follicles. Immunohistochemical studies showed that the neoplastic cells in the low- and high-grade components expressed the same class of immunoglobulin light chain in eight of the nine cases studied; staining in one case was unsatisfactory. Their intimate relationship as well as identical light chain restriction suggests that the high-grade component arises through blastic transformation of the low-grade component.

Development of neuroendocrine tumors in the gastrointestinal tract of transgenic mice. Heterogeneity of hormone expression.

Abstract: Expression of hormones in endocrine tumors and derived cell lines of transgenic mice carrying insulin-promoted oncogenes has been investigated by histochemical, immunohistochemical, ultrastructural, and radioimmunologic means Tumors of the pancreas, small intestine, mesentery, and liver were examined Insulin-immunoreactive cells were prevalent in pancreatic tumors, with a significant subpopulation of pancreatic polypeptide-immunoreactive elements Conventional ultrastructural and immunogold analysis identified insulin-storing beta granules in pancreatic tumor cells In contrast, the largest immunoreactive subpopulation of intestinal tumors expressed secretin (53% of total cells), followed by proglucagon-related peptides (15%), glucose-dependent insulinotropic polypeptide (7%), gastrin (7%), pancreatic polypeptide (2%), neurotensin (2%), and somatostatin (1%) No detectable immunoreactivity for either insulin or serotonin was observed Electron microscopy and immunogold labeling showed that intestinal tumor cells contained secretin-storing S-type granules Lymph node and liver tumors contained secretin-immunoreactive cells with ultrastructural features similar to those of intestinal tumors In addition, high levels of circulating insulinlike and secretinlike immunoreactants were detectable Analogous hormone profiles were identified in tumor cell lines and culture media Large T-antigen immunoreactivity was detected in all the nuclei of neoplastic cells, as well as in insulin-immunoreactive elements of non-neoplastic islets and pancreatic ducts and in some secretin-immunoreactive cells of small intestinal mucosa These data indicate that neuroendocrine tumors arise both in beta cell and S-cell subpopulations of transgenic mice

Neutrophil chemotactic factor (IL-8) gene expression by cytokine-treated retinal pigment epithelial cells.

Abstract: The neural-derived retinal pigment epithelium (RPE) underlies the sensory retina and is central to both retinal homeostasis and many common retinal diseases. Retinal pigment epithelium cells are actively phagocytic and share several features with macrophages that have recently been shown to produce a neutrophil chemotactic factor (NCF), also known as interleukin-8, after cytokine stimulation. Because RPE cell responses to cytokines are largely unknown, human RPE cell NCF production was monitored after interleukin-1-beta (IL-1 beta), tumor necrosis factor-alpha, or lipopolysaccharide stimulation. RPE NCF mRNA expression and RPE production of biologically active NCF was time and concentration dependent. Maximal NCF mRNA expression occurred at 20 ng/ml for IL-1 beta. Messenger RNA expression in RPE cells and biologically active NCF in RPE cell supernatants were found 1 hour after stimulation and were maintained for 24 hours. These findings demonstrate that cytokine-stimulated RPE cells may evoke or augment neutrophil-mediated inflammation by synthesizing NCF, a cytokine that may be important in ocular disease mechanisms.

Expression of the high molecular weight melanoma-associated antigen by pericytes during angiogenesis in tumors and in healing wounds.

Abstract: In the course of immunohistochemical characterization of murine monoclonal antibodies recognizing the human high molecular weight-melanoma associated antigen (HMW-MAA), a striking reactivity with blood vessels in the tumor stroma was noted. Immunocytochemical analysis by light and electronmicroscopy of a panel of tissues and cell lines showed that the staining of microvessels by anti-HMW-MAA monoclonal antibodies was restricted to pericytes. Correspondingly, anti-HMW-MAA monoclonal antibodies were found to react with cultured pericytes from human brain, but not with endothelial cells in serologic assays, and to immunoprecipitate from biosynthetically labeled pericytes an antigen with the characteristic structural profile of HMW-MAA. At the subcellular level, the expression of HMW-MAA in cultured pericytes was mainly restricted to microspikes that are localized in clusters on the cellular membrane. Staining by anti-HMW-MAA monoclonal antibodies of pericytes was not only found in the tumor stroma, but also in other lesions associated with angiogenesis, such as granulation tissue of wound healing and synovitis. In these lesions, microvascular staining for another marker of pericytes, ie, alpha-smooth muscle actin, also was observed. These results suggest that, in conditions associated with vascular proliferation, 1) pericytes acquire HMW-MAA and 2) the number of pericytes may be increased as compared with normal tissues.

Intrathecal application of interferon gamma. Progressive appearance of MHC antigens within the rat nervous system.

Abstract: Intrathecal injection of interferon-gamma induced a significant increase of the number of class I and class II major histocompatibility complex (MHC)-expressing cells within the rat nervous system. A progressive appearance of MHC-antigen-positive cells was found by light- and electron microscopic immune histology. The first level comprised cells that constitutively expressed MHC antigens in normal animals (meningeal and endoneural monocytes, some perivascular dendritic cells, and few parenchymal microglia cells, especially in the lumbar spinal cord and in the cerebellar white matter). The second level represented cells readily expressing MHC antigens after stimulation with interferon-gamma (all perivascular, dendritic cells, and microglia). The third level included ependymal cells, astrocytes, and Schwann cells. After stimulation with interferon-gamma, these neuroectodermal cells expressed MHC antigens inconsistently, usually in a low density and patchy distribution. The progressive appearance of MHC antigens may be reflected by the variances of lesional patterns found in experimental allergic encephalomyelitis of different histologic severity.

High glucose causes an increase in extracellular matrix proteins in cultured mesangial cells.

Abstract: Diabetic nephropathy is a major cause of the increased morbidity and mortality in insulin-dependent diabetes mellitus. The most significant renal lesion of diabetic nephropathy is expansion of the glomerular mesangium. Thickening of the glomerular basement membrance is also apparent. Mesangial expansion is largely due to the accumulation of extracellular matrix (ECM) proteins such as fibronectin, laminin, and type IV collagen. To determine whether high glucose is responsible for the observed increase in mesangial cell ECM protein accumulation, mesangial cells were grown in tissue culture medium containing 10 mmol/l (millimolar) glucose (normal) or 30 mmol/l glucose (high). The degree of ECM protein accumulation was determined by immunocytochemistry and a solid-phase enzyme-linked immunosorbent assay (ELISA) developed in the laboratory. Mesangial cells cultured for 1 week contained fibronectin as the most abundant ECM protein, followed by laminin and type IV collagen. Type IV collagen was seen only after the cells had piled up into 'hillocks' (approximately 4 weeks of continuous growth without passaging). After 4 weeks in 30 mmol/l glucose, mesangial cells contained increased amounts of all three matrix proteins. Fibronectin and laminin were increased by approximately 60%, while type IV collagen was increased 50%. Cells subcultured in medium containing 30 mmol/l glucose for 8 months displayed a twofold increase in fibronectin and laminin. Thus, high glucose per se can cause changes in mesangial cell ECM. This cell culture model should be useful in elucidating the mechanisms involved.

Decreased expression of integrin adhesive protein receptors in adenocarcinoma of the breast.

Abstract: The integrin superfamily represents a major class of receptors mediating cell-substrate adhesion. Our recent study of the tissue distribution of the alpha 2 beta 1 integrin, a cell-surface collagen receptor, revealed that high levels of receptor expression were associated with orderly, regulated epithelial cell proliferation. Those observations prompted the present investigation of alpha 2 beta 1 and other integrins in adenocarcinoma of the breast. The alpha 2 beta 1 integrin was highly expressed on the epithelium of the ducts and ductules of normal breast tissue. Normal or nearly normal levels of the receptor were expressed in fibroadenomas. In contrast, markedly decreased or undetectable alpha 2 beta 1 expression was typical of poorly differentiated adenocarcinomas. Well-differentiated lesions exhibited intermediate levels of expression. Similar, but less extensive, decreases in expression were observed for the alpha 5 beta 1 (fibronectin receptor) and alpha v beta 3 (vitronectin receptor). Significant expression of the beta 1 subunit on even poorly differentiated tumors suggests that the expression of other undefined members of the beta 1 family is not reduced to the same low level as alpha 2 beta 1 and alpha 5 beta 1. Expression of the alpha 2 beta 1 integrin was highly correlated with estrogen-receptor expression. Decreased expression of alpha 2 beta 1 and other integrin adhesive protein receptors probably contributes to the altered adhesive properties of tumor cells characteristic of the malignant phenotype.

Early accumulation of heparan sulfate in neurons and in the beta-amyloid protein-containing lesions of Alzheimer's disease and Down's syndrome.

Abstract: A monoclonal antibody (HK-249) that recognizes a glucosamine sulfate alpha 1----4 glucuronic acid-containing determinant in heparan sulfate (HS) chains of a basement membrane-derived heparan sulfate proteoglycan identified and immunolocalized HS specifically to the amyloid deposits in neuritic plaques (NPs), congophilic angiopathy (CA), as well as in neurofibrillary tangles (NFTs) and non-tangle-bearing neurons in the brains of Alzheimer's and Down's syndrome (DS) patients. Ultrastructural immunohistochemistry demonstrated that HS within neurons of Alzheimer's disease (AD) brain was localized to lipofuscin granules, an aging pigment previously shown also to contain beta-amyloid protein (BAP). Heparan sulfate also was localized to neurite-containing, nonfibrillar 'primitive' plaques that also demonstrated positive BAP immunoreactivity in both AD and DS brains. Antibodies to laminin, fibronectin, and a chondroitin sulfate proteoglycan failed to show positive immunostaining of the HS-containing sites described above. Analysis of DS patients at different ages revealed that HS accumulated within neurons of the hippocampus and amygdala as early as 1 day after birth. Young age-matched controls did not demonstrate similar positive HS immunoreactivity in neurons, whereas positive immunostaining for HS was observed in other regions thought to normally contain HS. The earliest deposition of BAP was first observed as 'amorphous' or 'diffuse' cortical deposits in DS brain in patients aged 18 and 24 years before the accumulation of fibrillar amyloid (observed in DS patients who are 35 years and older). These cortical deposits also contained positive HS immunoreactivity, implying that HS accumulation in conjunction with the BAP is an early event that ultimately may contribute to the early age-related accumulation (ie, as early as 35 years of age in DS) of NPs, NFTs, and/or CA. Furthermore the colocalization of HS and BAP in a number of specific locales in AD and DS brain indicates a possible interaction between these two macromolecules that may be important in lesion development in these two diseases.

Inhibition of angiogenesis and tumor growth in the brain. Suppression of endothelial cell turnover by penicillamine and the depletion of copper, an angiogenic cofactor.

Abstract: Microvascular proliferation, a hallmark of malignant brain tumors, represents an attractive target of anticancer research, especially because of the quiescent nonproliferative endothelium of the normal brain. Cerebral neoplasms sequester copper, a trace metal that modulates angiogenesis. Using a rabbit brain tumor model, normocupremic animals developed large vascularized VX2 carcinomas. By contrast, small, circumscribed, relatively avascular tumors were found in the brains of rabbits copper-depleted by diet and penicillamine treatment (CDPT). The CDPT rabbits showed a significant decrease in serum copper, copper staining of tumor cell nuclei, microvascular density, the tumor volume, endothelial cell turnover, and an increase in the vascular permeability (breakdown of the blood-brain barrier), as well as peritumoral brain edema. In non-tumor-bearing animals, CDPT did not alter the vascular permeability or the brain water content. CDPT also inhibited the intracerebral growth of the 9L gliosarcoma in F-344 rats, with a similar increase of the peritumoral vascular permeability and the brain water content. CDPT failed to inhibit tumor growth and the vascularization of the VX2 carcinoma in the thigh muscle or the metastases to the lung, findings that may reflect regional differences in the responsiveness of the endothelium, the distribution of copper, or the activity of cuproenzymes. Metabolic and pharmacologic withdrawal of copper suppresses intracerebral tumor angiogenesis; angiosuppression is a novel biologic response modifier for the in situ control of tumor growth in the brain.

Use of monoclonal antibodies to keratin 7 in the differential diagnosis of adenocarcinomas.

Abstract: Monoclonal antibodies (MAbs) to specific keratin subtypes were prepared and characterized by immunoblotting and immunohistochemical assays on human cell cultures and normal and malignant human tissues. Chain-specific MAbs to keratin 7 (RCK 105, OV-TL 12/30) and keratin 18 (RGE 53, RCK 106, CK18-2), as well as broadly cross-reacting keratin MAbs (RCK 102, OV-TL 12/5) could be shown to react with different types of human epithelial tissues and were therefore tested for their usefulness in the differential diagnosis of carcinomas. The two broad-spectrum antibodies stained virtually all of the more than 350 carcinomas tested, especially when combined, and distinguished them from most nonepithelial tumors. The keratin 18 MAbs distinguished adenocarcinomas (which are keratin 18 positive) from most squamous cell carcinomas (which are generally keratin 18 negative). The MAbs to keratin 7 could be shown to recognize specific subtypes of adenocarcinoma and could, for example, distinguish between ovarian carcinomas (keratin 7 positive) and carcinomas of the gastrointestinal tract (keratin 7 negative), or between transitional cell carcinomas (keratin 7 positive) and prostate cancer (keratin 7 negative). In general, malignancies showed the expected keratin reactivity pattern as concluded from the keratin pattern of its cell of origin or its type of differentiation. The use of an extended series of malignancies did, however, also illustrate that exceptions to this rule exist. For example, certain antibodies to keratin 18 stained tumor areas in squamous cell carcinomas of the lung. Also a certain percentage of tumors, which generally showed no keratin 7 expression, were positive with RCK 105 or OV-TL 12/30. On the other hand, a certain percentage of tumors, which were generally positive for keratin 7, did not show a staining reaction with these MAbs. Furthermore subtle differences between reactivity patterns of different MAbs recognizing the same keratin protein were observed, both in the normal and malignant human tissues, indicating that specific keratin epitopes may be masked in certain tissues and that unmasking of such epitopes can occur with malignant progression. This phenomenon may be of some use in a further subtyping of carcinomas, especially those of the gastrointestinal tract. Despite these exceptional staining patterns, the keratin MAbs described above have proved to be useful tools in the characterization of epithelial tumors in routine histopathology and cytopathology, in which they add to a more refined diagnosis of (adeno)carcinomas.

High incidence of Epstein-Barr virus genomes in Hodgkin's disease.

Abstract: Tissue specimens from 198 cases of Hodgkin's disease and 151 non-Hodgkin lymphomas, as well as 34 nonmalignant lymph node biopsies were examined for the presence of Epstein-Barr virus (EBV) DNA by polymerase chain reaction. Epstein-Barr virus-specific DNA sequences were detected in DNA extracts from frozen and/or paraffin-embedded tissues of 58% of Hodgkin's disease cases. High and low grade non-Hodgkin lymphomas as well as chronic lymphocytic leukemia biopsies contained EBV DNA in 26%, 14%, and 7% of the cases, respectively. Ten percent of the control lymph nodes with normal histology were EBV positive. In Hodgkin's disease biopsies, subsequent in situ hybridization revealed an exclusive localization of the viral DNA in the tumor cells. These findings suggest an involvement of EBV in the pathogenesis of Hodgkin's disease in a substantial proportion of cases.

Diffuse plaques do not accentuate synapse loss in Alzheimer's disease.

Abstract: Applying the relatively new technique of laser confocal imaging, vibratome sections which were double immunolabeled for amyloid beta protein and the presynaptic terminal marker synaptophysin were examined. It was found that while synaptic density was generally diminished in Alzheimer's disease (AD) cortical neuropil as compared to controls, the reduction was no greater within the diffuse plaques than outside them. Synapse loss was accentuated, however, within immature and mature plaques. These findings suggest that the pathogenetic process in AD might commence with synapse loss and neurodegeneration rather than with deposition of amyloid beta protein.

Detection of HLA-DR on microglia in the human brain is a function of both clinical and technical factors.

Abstract: Detection of HLA-DR, a class II major histocompatibility antigen, on glial cells is dependent not only on duration and type of tissue fixation and processing, but also on clinical factors. Glial cells labeled by anti-HLA-DR were consistent with microglia by light microscopic and ultrastructural criteria, and were colabeled with other microglial markers, including LN-1, Leu-M5, and leukocyte common antigen (LCA). In young and elderly subjects who died suddenly, anti-HLA-DR labeled microglia in the white matter, but far fewer cells in the gray matter. In subjects who died of chronic debilitating illness, such as Alzheimer's disease and carcinomatosis, anti-HLA-DR labeled numerous microglia throughout both the gray and white matter. In Alzheimer's disease, microglia were aggregated in compact senile plaques, but loosely associated with diffuse amyloid deposits. These results suggest that HLA-DR may be constitutively expressed in white matter, but induced in gray matter microglia in chronic disease states or in association with amyloid deposits.

Influence of the angiotensin system on endothelial and smooth muscle cell migration.

Abstract: The blood vessel wall's response to injury is an important determinant of luminal size and vessel function. The physiologic migration of endothelial cells from the edges of a wound and the pathophysiologic migration of medial smooth muscle cells into the intima are two important components of the vessel wall's response to injury. The influence of the angiotensin system on endothelial and smooth muscle cell migration have not been examined. In the present study, the influence of angiotensin system components on bovine aortic endothelial cell (BAEC) and bovine aortic smooth muscle cell (BASMC) migration after release of cultured cell monolayers from contact inhibition was determined. The angiotensin-converting enzyme (ACE) inhibitor lisinopril increased BAEC migration 41% +/- 3% (P less than 0.001), as did the specific angiotensin II antagonist sar1, ile8-angiotensin II (SAR) (41% +/- 3% (P less than 0.001). Exogenous angiotensin I and angiotensin II did not affect BAEC migration. Exogenous angiotensin II abolished the effect of lisinopril on BAEC migration. Lisinopril increased cell-associated u-plasminogen activator (u-PA) 23% +/- 3% (P less than 0.001) in migrating BAEC and angiotensin II abolished this increase. SAR increased u-PA 33% +/- 0% (P less than 0.001). In contrast, these agents had the opposite effect on smooth muscle cells. Angiotensin II increased smooth muscle cell migration 40% +/- 3% (P less than 0.001), and this effect was abolished by SAR. Angiotensin II also increased cell-associated u-PA 83% +/- 7% (P less than 0.001) in migrating BASMC. The increase in BAEC migration with inhibition of endothelial cell angiotensin II stimulation, either with lisinopril or SAR, also was associated with an increase in cell-associated u-PA. These results indicate that lisinopril interrupts an autocrine pathway in endothelial cells, in which endothelial cell-derived angiotensin I is converted to angiotensin II by ACE, and imply that angiotensin-converting enzyme inhibitors in vivo would act to reduce vessel wall injury by directly increasing the rate of endothelial cell wound closure; by increasing the antithrombotic tendency of the endothelium via enhanced u-PA; and indirectly, by decreasing production of angiotensin II and thereby the rate of smooth muscle cell migration into the intima.

Intercellular adhesion molecule-1 (ICAM-1) expression is upregulated in autoimmune murine lupus nephritis.

Abstract: Intercellular adhesion molecule-1 (ICAM-1) is a cell-surface protein regulating interactions among immune cells. To determine whether altered expression of ICAM-1 occurs in autoimmune lupus nephritis, we studied ICAM-1 expression in kidneys of normal and autoimmune MRL-lpr and (NZBX NZW)F1 (NZB/W) mice. By immunoperoxidase staining, ICAM-1 is constitutively expressed at low levels in proximal tubules (PT), endothelium and interstitial cells in normal C3H/FeJ mice. In nephritic MRL-lpr and NZB/W kidneys, staining for ICAM-1 is increased in the PT, particularly in the brush border, and is prominent in the glomerular mesangium and the endothelium of large vessels. By Western blot analysis, ICAM-1 is not detected in the urine of normal BALB/c and C3H/FeJ or autoimmune MRL-lpr. By Northern blot analysis, nephritic MRL-lpr and NZB/W have a two- to fivefold increase in steady state levels of ICAM-1 transcripts in the kidney as compared with normal or prenephritic mice. This is paralleled by an increase in MHC class II transcripts. In cultured PT cells, ICAM-1 is expressed at basal levels in PT and is increased by the cytokines interferon-gamma, IL-1 alpha, and TNF-alpha. Thus cytokine-mediated upregulation of ICAM-1 in lupus nephritis may promote interaction of immune cells with renal tissue. The predominant apical expression of ICAM-1 opposite to the basolateral Ia expression suggests a novel role for this adhesion molecule in PT.

Cellular localization of an HIV-1 antigen in subacute AIDS encephalitis using an improved double-labeling immunohistochemical method

Abstract: Among 102 brains obtained from patients with acquired immune deficiency syndrome (AIDS), 34 cases with subacute AIDS encephalitis were characterized by immunohistochemistry using an antibody that binds to a human immunodeficiency virus-1 (HIV-1) envelope glycoprotein, gp41. This glycoprotein was detected in mononucleated and/or multinucleated cells in 90% of adult and 50% of pediatric brains with subacute AIDS encephalitis. In addition, many gp41-positive cells with bipolar or multipolar processes were found in 10 cases, and these cells occurred most frequently in the basal ganglia and internal capsule. The phenotype of the gp41-positive cells was determined using an improved double-labeling immunohistochemical technique that employed beta-galactosidase and peroxidase conjugated reagents. Cell-type specific markers for double-labeling included: Ricinus communis agglutinin-1 (RCA-1) for macrophages and microglia; Ulex europaeus agglutinin-1 for endothelium; anti-glial fibrillary acidic protein (GFAP) for astrocytes; anti-amyloid precursor protein for neurons; and anti-leukocyte common antigen for leukocytes. Results of double-immunostaining revealed that gp41-positive cells of all morphologic types, including cells with bipolar or multipolar processes, were double-labeled with RCA-1, but not with markers for astrocytes, neurons, or endothelia. These findings support the contention that HIV-1 infection of the CNS is predominantly restricted to cells of the macrophage/microglia lineage.

Heparin modulates the composition of the extracellular matrix domain surrounding arterial smooth muscle cells.

Abstract: Heparin and related molecules influence vascular wall structure by their ability to inhibit smooth muscle cell (smc) proliferation and migration. However, little is known as to whether heparin has an effect on the extracellular matrix. In the present study, the effect of heparin on the content and regional distribution of elastin, collagen, and proteoglycans (PGs) in blood vessels following experimental injury was determined. Two groups of rats were subjected to left common carotid balloon injury and were infused with either 0.9% saline or heparin in a saline solution, for 2 weeks. Using a new morphometric method of analysis, the authors determined changes in volumes of elastin, collagen, and PGs contained within an 'extracellular matrix domain (ECM domain),' the average envelope of connective tissue surrounding each smc. Heparin treatment inhibited intimal thickening and decreased the elastin content in the ECM domain in the upper and lower arterial intima. Collagen also was found to be significantly decreased 5.0-fold and 7.6-fold in the ECM domains of upper and lower intima, respectively, of heparin-treated animals. The decrease in both elastin and collagen was balanced by a significant increase in amorphous and filamentous electron-dense material. Heparin also caused a significant 1.8-fold and 1.9-fold increase in the PG content in the ECM domain in the upper and lower intima, respectively. Immunohistochemical analysis, using antibodies to elastin and PG subclasses, supported the morphometric observations. This study has shown that heparin administered in vivo can alter the accumulation and distribution of each of the major vascular ECM components in a specific and differential manner.

Platelets mediate glomerular cell proliferation in immune complex nephritis induced by anti-mesangial cell antibodies in the rat.

Abstract: We investigated whether platelets, which are rich in growth factors, could mediate glomerular cell proliferation in immune complex glomerulonephritis (GN) in the rat induced with an antibody directed against the Thy-1 antigen present on mesangial cells. Rats were depleted of platelets (mean platelet count less than 20,000/mm3) with goat anti-rat platelet IgG before induction of GN and platelet depletion was maintained for 48 hours. At 72 hours sections were immunostained for cyclin, an S-phase-related nuclear antigen, to identify proliferating cells, and for the common leukocyte antigen (CD45) to identify infiltrating leukocytes. Platelet depleted rats had fewer proliferating resident glomerular cells (CD45-, cyclin+) compared to controls (0.8 +/- 0.5 vs. 2.8 +/- 1.4 cells/glom cross section, P less than 0.01) and better renal function (creatinine 1.07 +/- 0.12 vs. 1.27 +/- 0.15 mg/dl, P less than 0.05). These effects were not due to changes in circulating or glomerular leukocyte counts, complement, or glomerular antibody binding. These studies provide the first direct evidence that platelets mediate glomerular (probably mesangial cell) proliferation in antibody-mediated GN.

Tumor necrosis factor gene expression in human vascular intimal smooth muscle cells detected by in situ hybridization.

Abstract: We used immunohistochemistry to detect tumor necrosis factor (TNF) and in situ hybridization to detect TNF messenger RNA (mRNA) in the intimal mesenchymal-appearing cells and in the medial smooth muscle cells of human atherosclerotic arteries. Medial smooth muscle cells showed localization of immunoreactive TNF on the cell surface and did not express TNF mRNA. Conversely, in intimal mesenchymal-appearing cells, TNF was localized in the cytoplasm and TNF mRNA was expressed by in situ hybridization. Thus 89% of intimal cells were immunohistochemically positive for TNF, 96% of them were positive by in situ hybridization, and 76% were positive for the smooth muscle cell marker, HHF35. Our results suggest that intimal mesenchymal-appearing cells are mostly, but not exclusively, derived from smooth muscle cells. These cells express TNF, whereas the medial smooth muscle cells in the atherosclerotic human arteries do not. The expression of TNF by these mesenchymal-appearing cells may have implications regarding the evolution of the atherosclerotic plaque.