Biomedical subjects

S A Hearn

Publications and source records attributed to S A Hearn.

14 recordsLinked to original sources

PubMed1991

Primary localized amyloidosis of the lacrimal glands.

Primary localized amyloidosis causing bilateral lacrimal enlargement is rare. The pathogenesis of amyloid deposition within the orbit and other body tissues has not been fully elucidated. The authors report the case of a 72-year-old woman who presented with bilateral lacrimal gland enlargement secondary to amyloid infiltration. The chemical nature of the deposit was characterized using light microscopy, immunohistochemistry, and immunoelectron microscopy. The primary (immunocytic) nature of the amyloid was confirmed by immunohistochemistry demonstrating the presence of monoclonal lambda light chains in the amyloid deposits and in the plasma cells. Using immunoelectron microscopy, amyloid deposits were seen containing lambda light chains in macrophages. It has been postulated that the macrophage has a role in amyloid deposition. The authors believe this to be the first published report of immunoelectron microscopy use in orbital amyloidosis, and that this technique has helped further their understanding of the nature and pathogenesis of this condition.

Aged↗

PubMed1991

Immunoelectron microscopic localization of chlamydial lipopolysaccharide (LPS) in McCoy cells inoculated with Chlamydia trachomatis.

Interactions between Chlamydia trachomatis, host cells, and the immune system are believed to involve lipopolysaccharide (LPS). We used immunogold techniques to study the distribution of chlamydial LPS in cultured cells infected with C. trachomatis LGV-L1. McCoy cells inoculated with C. trachomatis were cultured and then fixed and embedded in situ with acrylic resins. Sections were immunolabeled with a protein A-gold method using antisera to the genus-specific, periodate-sensitive epitope on chlamydial LPS. Pre-embedding immunogold labeling on permeabilized cells was also done. By post-embedding methods, labeling for LPS was equally abundant over the outer membranes of elementary (EB) and reticulate bodies (RB). By post-embedding labeling, the sub-surface side of the EB outer membrane was more heavily labeled than the surface side. By pre-embedding labeling, LPS was found to be less abundant on the surface of EBs than RBs. Labeling for LPS was found over apparent lysosomes in McCoy cells and over electron-dense blebs on or near the surface of the plasma membranes of McCoy cells. These results indicate that the concentration of LPS in chlamydial membranes is constant during development but that with development its location changes from being mostly cell-surface to sub-surface. These results show that the post-embedding immunogold technique can be a useful approach for the cell culture-based study of chlamydial LPS.

Acrylic Resins↗

PubMed1990

Primary endodermal sinus tumor of the endometrium. A clinicopathologic, immunocytochemical, and ultrastructural study.

We report a case of primary endodermal sinus tumor (EST) of the endometrium in a 42-year-old female. Although numerous extragonadal EST have been reported, primary EST of the endometrium is exceedingly rare. To our knowledge this is the fourth documented case of this nature. The tumor had the typical microscopic features of EST, with papillary, tubular, reticular, and solid growth patterns; occasional Schiller-Duval bodies and many intracellular and extracellular periodic-acid Schiff positive hyaline globules were seen. The neoplastic cells stained positively for alpha-fetoprotein (AFP), alpha-1-antitrypsin (A1AT), cytokeratin, and placental alkaline phosphatase. The globules were positive for AFP, A1AT, albumin, transferrin, and fibronectin. The tumor cells were negative for type IV collagen and the beta subunit of human chorionic gonadotropin (B hcG). Electron microscopic examination showed intracellular and extracellular basement membrane-like material, intracytoplasmic lumina with microvilli, and glycogen. The patient was treated with total abdominal hysterectomy and bilateral salpingo-oophorectomy, followed by four cycles of adjunct chemotherapy (vinblastine, bleomycin, and cisplatinum) repeated every 3 weeks. The serum AFP level was elevated significantly before the surgery and the tumor response was monitored by serial determination of serum AFP level. There was no evidence of recurrence 24 months after surgery.

Adult↗

PubMed1990

Immunogold labelling of tumour cells during NK/target cell interactions.

Using a system of immunocolloidal gold labelling, we have monitored the expression and distribution of transferrin receptors (TfRs) within the K562 cell line, during NK/target cell interactions. An indirect method of immunolabelling was used to effectively immunolabel tumour cells without disrupting the natural effector:target interactions. Successful localization of TfRs demonstrates the potential of the described technique for discerning antigenic distribution of other cell:cell interactions. Immunolabelling has also provided a useful method for demonstrating receptor down-regulation within NK target cells, as a proposed cause of reduced receptor expression by TPA-treated cells. Following 30 and 60 min incubation periods with TPA, approximately 15 and 30%, respectively, of the gold/antibody complexes were relocated from the surface membrane to an intracellular location within endocytotic vesicles. The demonstration of receptor down-regulation is important as a proposed cause of TPA-induced tumour cell resistance to NK-mediated cytolysis.

Cytotoxicity, Immunologic↗

PubMed1990

Immunogold quantitation of immunoglobulin light chains in renal amyloidosis and kappa light chain nephropathy.

By quantitative immunoelectron microscopy using protein A-gold, the authors compared the content and distribution of immunoglobulin light chain (LC) antigens in glomeruli from 11 cases of renal amyloidosis with that in two cases of kappa LC glomerulopathy and two cases of diabetic glomerulosclerosis. In a supplementary study and using a similar immunogold technique, the authors identified amyloid A in deparaffinized renal tissue from three of the 11 cases of renal amyloidosis. Each patient had similar clinical manifestations (chronic renal failure with proteinuria) and similar glomerular morphology (thickened glomerular basement membranes and nodular expansion of the mesangium). In 12 cases (10 amyloid, 2 kappa LC), immunoelectron microscopy localized LC antigens over the glomerular deposits and allowed indirect tissue quantitation of each LC antigen to the various cellular and interstitial compartments. In 6 of the 11 cases of renal amyloidosis, the amyloid labeled only for lambda, and in one, only for kappa. In one patient with Waldenström's macroglobulinemia, who had a biclonal gammopathy, both LC were identified in the amyloid. In two cases, both of whom had a history of chronic suppurative lung disease, both LC antigens as well as amyloid A were localized to the amyloid fibrils. In only one case, in which glomerular amyloid labeled for amyloid A, the amyloid did not label for either LC. Whereas lambda LC-derived fibrils often appeared as spicules in the glomerular subepithelial space, other amyloid deposits usually accumulated in the subendothelial zone and did not form spicules. The epimembranous location of spicules suggested that the amyloid precursor protein transformed into amyloid fibrils after filtration into the urinary space. Presence of epimembranous spicules may explain the more severe proteinuric renal failure and the more rapid progression to glomerulosclerosis described in primary amyloidosis.

Amyloidosis↗

PubMed1990

Human monoclonal antibodies to neuroendocrine granules derived from tumor-infiltrating lymphocytes isolated from a primitive neuroectodermal tumor.

Tumor-infiltrating lymphocytes were isolated from a primitive neuroectodermal tumor and fused with GM4672 cells, resulting in hybrids secreting human IgM-kappa antibody, which is reactive to olfactory neuroblastoma tumor cells. Hybridoma clones 4F and 9G produce human monoclonal antibodies reactive to autologous and allogeneic neuroblastoma tumor cells and subsets of pancreatic islet cells in formalin-fixed tissues. They react specifically with dense core granules of glucagon and insulin-producing islet cells, but not with those in cells producing somatostatin. Calcitonin granules are not recognized by these antibodies. The area of localization of the granules is distinct from the component labeled by murine monoclonal antibodies to chromogranin A. The clones have remained stable in culture for over two years and continue to secrete up to 60 micrograms/mL of human IgM. This study demonstrates the possibility of directly analyzing the antibody repertoire of tumor-infiltrating B cells, and this technique may allow the development of human monoclonal antibodies to other novel cellular antigens.

Antibodies, Monoclonal↗

PubMed1990

Proteinaceous lymphadenopathy due to monoclonal nonamyloid immunoglobulin deposit disease.

We report two cases of lymph node enlargement due to massive extracellular nonamyloid immunoglobulin deposits that obscured the underlying cellular pathologic condition. In both cases, the deposits were demonstrated to be restricted to a single heavy and light chain, consistent with a monoclonal paraprotein, and cytoplasmic staining in the lymphocytes or plasma cells was identical to that of the paraprotein. The use of the protein A-gold technique was instrumental in revealing a monoclonal pattern in one case in which light microscopic immunohistochemistry did not reveal a clear-cut monoclonal pattern in the extracellular deposits. This case was subsequently shown to have multiple myeloma, while the second case has had an unusual history of hypocomplementemic vasculitis and normal bone marrow. Neither case had evidence of significant renal disease.

Adult↗

PubMed1989

Neuropathy in IgM lambda paraproteinemia. Immunoreactivity to neural proteins and chondroitin sulfate.

In axonal neuropathies associated with IgM paraproteinemia, reports of antigen specificity of the M-protein are few. A patient with IgM paraproteinemia presented with progressive mononeuritis multiplex. IgM was found deposited in striking amounts in endoneurium and shown to bind specifically to neural proteins and chondroitin sulfates. Direct immune mechanisms, as well as the physical effects of IgM deposition, likely contributed to the development of the neuropathy.

Aged↗

PubMed1989

Postembedding immunogold electron microscopy for S100, tubulin, and cytoskeletal proteins in an amelanotic malignant melanoma.

A postembedding Protein A-colloidal gold technique was used for the ultrastructural immunocytochemical investigation of S100, tubulin, and cytoskeletal proteins in a Lowicryl K4M-embedded melanoma with numerous microtubules. S100 protein was localized in the cytoplasm and the nuclei of tumor cells. Melanosomes were not labeled with S100. Perinuclear intermediate filaments and filaments in cytoplasmic processes reacted positively for vimentin. The straight, rod-shaped, parallel intracisternal microtubules failed to react with antisera to tubulin, S100, vimentin, cytokeratin, neurofilaments, desmin, glial fibrillary acidic protein, and immunoglobulin light chains. These results give an improved correlation between the ultrastructural and immunocytochemical characteristics of the tumor, confirm the melanocytic origin of it, and demonstrate the application and usefulness of the postembedding immunogold method in the investigation of the protein composition of subcellular structures.

Cytoskeletal Proteins↗

PubMed1988

Calcitonin and chromogranin A localization in medullary carcinoma of the thyroid by immunoelectron microscopy.

We used a post-embedding immunoelectron microscopy method, using protein A-gold, to detect calcitonin and chromogranin A immunoreactivity in three cases of human medullary thyroid carcinoma. Because the epoxy-embedded tissue had been fixed (glutaraldehyde or formaldehyde) and osmicated before embedment, the proteins were identified in optimally preserved tissue. Uranyl and lead staining was used after immunolabeling, so that the tissue was also optimally contrasted. The morphological advantage provided by osmication was tested by labeling rat thyroid gland C-cells for calcitonin. The protein A-gold technique allowed localization of both antigens to the contents of membrane-bound secretory granules in the tumor cells. In one case, labeling density for each antigen was measured over several intercellular compartments and the interstitium. Calcitonin, but not chromogranin A, reactivity was also identified in intracellular amyloid fibrils in two cases, showing that the constant region of calcitonin is preserved in amyloid deposits related to the tumor cells.

Calcitonin↗

PubMed1987

Electron microscopic localization of chromogranin A in osmium-fixed neuroendocrine cells with a protein A-gold technique.

An antibody (LK2H10) to chromogranin A has been recommended for use in ultrastructural identification of neuroendocrine secretory granules. Previous studies have demonstrated immunoreactive chromogranin A in specimens prepared for electron microscopy by glutaraldehyde fixation only. In this study, the effect of specimen post-fixation by osmium tetroxide on post-embedding localization of chromogranin A was evaluated. Human tissues from benign endocrine glands, neuroendocrine tumors, and non-neuroendocrine tumors were post-fixed in osmium, embedded in epoxy resin, and the sample thin sections immunolabeled using a protein A-gold technique. Chromogranin A-positive neurosecretory granules were detected in pancreatic islets, adrenal medulla, stomach, ileum, anterior pituitary, and parathyroid. Mid-gut carcinoids, bronchial carcinoids, pheochromocytomas, paragangliomas, carotid body tumors, and thyroid medullary carcinomas contained immunoreactive granules. Cytoplasmic granules in non-neuroendocrine tumors did not react for chromogranin A. Tissues post-fixed in osmium tetroxide had optimally preserved ultrastructural features, and use of this fixative is compatible with postembedding localization of chromogranin A in neurosecretory granules.

Carcinoid Tumor↗

PubMed1987

Postembedding immunoelectron microscopy using protein A-gold.

Immunogold techniques offer the advantage of identifying antigens in tissues that show optimal ultrastructural morphology. The technique is applicable to any antigen that can be shown to withstand the denaturizing effects of fixation, osmication, dehydration, and embedding in epoxy resin. The list of antigens that survive these procedures is long and growing.

Antigens↗

PubMed1986

Renal and systemic kappa light chain deposits and their plasma cell origin identified by immunoelectron microscopy.

Kappa light chain determinants were identified by immunoelectron microscopy in nodular glomerulosclerotic lesions and systemic interstitial deposits from a man who died several years after the onset of proteinuric renal failure treated by hemodialysis. He developed adrenal and hepatic failure preterminally but not overt malignant myeloma. Specific labeling was most concentrated over the inner aspect of glomerular basement membrane and the mesangium, which suggested that the protein was nonfiltrable. Tubular basement membrane labeling was densest over the outer aspect, which suggested that the protein perfused from the interstitium rather than from the tubular lumen. We identified the source of the protein as a population of plasma cells present within bone marrow and renal interstitium; these showed specific immunogold labeling for kappa light chain protein over organelles concerned with protein synthesis, secretion, and storage. This appears to be the first identification of light chain determinants in human interstitial para-amyloid deposits with the use of immunogold ultrastructural techniques in tissues prepared for electron microscopy by standard methods and stored as epoxy resin blocks.

Adrenal Glands↗

PubMed1985

Immunoelectron microscopic labeling of immunoglobulin in plasma cells after osmium fixation and epoxy embedding.

Previous studies have found that immunoglobulin cannot be immunolabeled in tissues prepared for electron microscopy by usual methods. To test this conclusion, we used a protein A-gold postembedding immunolabeling method on tissues that were fixed in glutaraldehyde, post-fixed in osmium tetroxide, and embedded in epoxy resin; sections were pretreated with sodium metaperiodate. A variety of common fixation protocols were also used and the most suitable conditions for immunolabeling were determined. This technique permitted the ultrastructural localization of immunoglobulin light chains in optimally preserved and contrasted plasma cells from human tonsil, lymph nodes, plasmacytomas, and a renal biopsy. We were able to demonstrate multiple antigens in the same tissue and label antigens in tissues that had been stored for many years in epoxy resin. The technique allows quantitation of the gold label over plasma cell organelles and therefore gives information about the immunoglobulin secretory pathway in these cells. We found that the protein A-gold procedure compares favorably in technical ease with the immunoperoxidase, avidin-biotin peroxidase, and immunoglobulin-colloidal gold immunolabeling methods, and has added advantages in allowing precise localization and quantitation of the labeled antigen.

Epoxy Compounds↗