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Biomedical subjects

D Bani

Publications and source records attributed to D Bani.

At least 55 records · Page 3Linked to original sources
PubMed1992

Characterization of a novel cell line from pleomorphic adenoma of the parotid gland with myoepithelial phenotype and producing interleukin-6 as an autocrine growth factor.

A cell line was obtained from a primary culture of a pleomorphic adenoma of the parotid gland in a 24-year-old woman. The cells of the line (PA 16/23) grew spontaneously in minimal culture conditions and showed stable morphologic characteristics over 30 passages. PA 16/23 cells had immunophenotypic and ultrastructural features similar to those of transformed myoepithelial cells, which are regarded as the precursors of pleomorphic adenomas. Furthermore, these cells have been demonstrated immunocytochemically to contain interleukin-6 (IL-6) on light and electron microscopic examination. IL-6 also has been found by enzyme-linked immunosorbent assay in the culture supernatant and has been proven to be capable of stimulating growth of the PA 16/23 cells.

Adenoma, Pleomorphic↗
PubMed1992

Detection of P-glycoprotein on endothelial and endocrine cells of the human pancreatic islets by C 494 monoclonal antibody.

P-glycoprotein, an integral membrane protein acting as an energy-dependent efflux pump, has been detected immunocytochemically in the human pancreatic islets using C 494 monoclonal antibody. Intense P-glycoprotein immunoreactivity was found in both endothelial cells of islet blood capillaries and in endocrine cells. Strong expression of P-glycoprotein has been found in the capillary blood vessels at blood-tissue barrier sites and in numerous kinds of cells with secretory/excretory function. Therefore the present findings suggest that P-glycoprotein may play a role in controlling the composition of the extracellular fluids and the intracellular milieu of endocrine islet cells and possibly in regulating their secretory activity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

Structural changes of the exocrine pancreas in a patient with cholecystolithiasis.

The exocrine pancreas has been studied histologically, morphometrically, and ultrastructurally in a patient with cholecystolithiasis in comparison with three control patients free from gastrointestinal or pancreatic diseases. In the gallstone-bearing patient, acinar cells undergo a significant increase in the average cell area and average zymogenic area (i.e., the portion of acinar cell cytoplasm occupied by zymogen granules). In addition, these cells showed cytological signs of enhanced synthesis of secretory proteins and increased formation and release of zymogen granules. The findings concerning centroacinar/ductular cells are consistent with a significant increase in their number and average cell area that is associated with ultrastructural signs of enhanced functional activity.

Adult↗
PubMed1992

Are pancreatic VIPomas paraneuron neoplasms? A clue to the neuroectodermal origin of these tumors.

Three pancreatic vasoactive intestinal polypeptide (VIP)-producing tumors associated with the watery diarrhea-hypokalemia-achlorhydria syndrome were studied histologically, ultrastructurally, and immunocytochemically. All the tumors contained varying numbers of cells arranged in pseudoglandular structures. The cells showed a polar organization, with apical tuft of microvilli and basal VIP-containing, synaptic vesicle-like granules. Based on the morphology of the VIPoma cells typical of recepto-secretory cells, together with the ability to synthesize and release a peptide that in normal conditions is expressed exclusively by neurons, and the absence of VIP-producing endocrine cells in normal pancreas and gastrointestinal mucosa, the hypothesis is drawn that the pancreatic VIPomas reported here are paraneuron neoplasms, which possibly originate from neuroectodermal ancestors.

Adult↗
PubMed1992

Immunocytochemical and ultrastructural abnormalities of islet tissue in patients with VIP-producing tumors of the pancreas.

Nontumoral endocrine pancreas from three patients with malignant vasoactive intestinal polypeptide (VIP)-omas and the Verner-Morrison (watery diarrhea, hypokalemia, and hypoachlorhydria) syndrome was studied immunocytochemically, ultrastructurally, and morphometrically. Compared with normal islets from control subjects, those of the VIPoma-associated pancreas showed a decrease of immunoreactive insulin in B-cells associated with cytological features indicative of enhanced insulin synthesis and secretion and an increase in the number of immunoreactive somatostatin- and pancreatic polypeptide-containing cells, in the absence of ultrastructural signs of modified secretory activity. No substantial alterations of A-cells were observed. In addition, images of diffuse de novo formation of ducts and islet tissue were often found. Possible mechanisms involved in determining the above changes are discussed.

Adult↗
PubMed1991

Human bone marrow non-B, non-T cells produce interleukin 4 in response to cross-linkage of Fc epsilon and Fc gamma receptors.

Human bone marrow (BM) cells lacking T- and B-cell markers expressed RNA encoding interleukin (IL) 4 and secreted detectable amounts of IL-4 in supernatants in response to Fc epsilon or Fc gamma receptor (Fc epsilon R or Fc gamma R) cross-linking. In some experiments, IL-5 RNA expression in response to Fc epsilon R cross-linkage could also be detected. In contrast, RNA transcripts for, and secretion of, IL-2, IL-6, and interferon gamma were never observed. The presence of IL-3 in the cultures was essential for IL-4 production by non-B, non-T BM cells in response to Fc gamma R cross-linking and enhanced IL-4 RNA expression in response to Fc epsilon R cross-linking. Under the same experimental conditions, BM T and B lymphocytes, as well as peripheral blood T, B, and non-B, non-T cells, did not express IL-4 RNA. Prolonged incubation of non-B, non-T cells in IgE-free medium followed by extensive washing did not inhibit IL-4 production induced by anti-IgE antibodies, suggesting that the Fc epsilon R involved in the response has the characteristics of a high-affinity receptor. The Fc epsilon R+ cells were separated from the Fc epsilon R- cells by sorting non-B, non-T BM cell suspensions with fluorescein isothiocyanate-conjugated IgE and then assessed for both IL-4 RNA expression and alcian blue staining. Both IL-4-producing and alcian blue-positive cells segregated with the Fc epsilon R+ fraction. These data suggest that human BM cells, probably belonging to the mast cell and/or basophil lineage, are capable of producing IL-4 in response to Fc epsilon R or Fc gamma R cross-linkage.

Antigens, Differentiation↗
PubMed1991

Morphological changes in the human endocrine pancreas induced by chronic excess of endogenous glucagon.

The non-tumoral endocrine pancreas from a patient with elevated plasma levels of glucagon due to a malignant glucagonoma was studied immunocytochemically, ultrastructurally and morphometrically. Compared with normal pancreatic islets from control subjects, those of the pancreas from the patient with a glucagonoma showed an almost complete disappearance of A cells, a decrease in immunoreactive insulin in B cells associated with cytological features indicating enhanced synthesis and secretion of this hormone, and an increase in immunoreactive somatostatin and pancreatic polypeptide (PP) accompanied by unusually high numbers of D and PP cells. In addition, numerous B cells were found outside the islets, either forming micro-islets or scattered in the exocrine tissue (nesidioblastosis). The possible mechanisms involved in determining the changes in the secretory activity of B cells and the alterations in the cell composition of the islets are discussed.

Adolescent↗
PubMed1991

Does the epithelium play a central role in the immune function of rhinopharyngeal tonsils? An immunocytochemical and ultrastructural study.

Enlarged adenoids from 10 children with chronic rhinitis and otitis media with effusion have been studied immunocytochemically and ultrastructurally, to better define the possible role of the epithelium and the dendritic accessory cells in the immune activation of lymphoid cells, and provide further insight into the pathogenesis of the disease. The presence within the columnar epithelium of lymphocytes positive for CD8 antigen, and which electron microscopically have been found frequently apposed to degenerating epithelial cells suggests that the latter cells are targets for cytotoxic activity of intraepithelial lymphocytes, rather than being engaged in antigen presentation. Furthermore, the finding of typical dendritic accessory cells, recognized by their typical immunophenotypic and ultrastructural features, in the lamina propria, indicates that antigen presentation is more likely exerted by dendritic accessory cells. This is further supported by the fact that these cells express major histocompatibility (MHC) class II molecules, which are needed for antigen presentation, whereas epithelial cells do not. A possible relationship between epithelial damage and the pathogenesis of adenoidal enlargement is discussed.

Adenoids↗
PubMed1991

Interdigitating cells in the peritumoral infiltrate of laryngeal carcinomas: an immunocytochemical and ultrastructural study.

Interdigitating cells (IDCs) have been found in the peritumoral infiltrate of 18 patients with squamous cell carcinoma of the larynx. These cells have a dendritic shape and are characterized by the expression of S-100 protein and CD1a antigens. By electron microscopy, these cells are seen to establish intimate contacts with the apposed lymphocytes, which sometimes show signs of functional activation and proliferation. These findings indicate that IDCs may play a role in setting up a T-cell immune reaction against neoplastic cells, which may influence the biological behaviour and/or local growth of the tumour. Moreover, monocytes and cells with intermediate features between monocytes and IDCs are also found in the peritumoral infiltrate, thus suggesting that IDCs differentiate in situ from monocytic precursors, possibly under the influence of either tumour-derived factors or the local lymphoid microenvironment.

Aged↗
PubMed1990

Interleukin 1 is an autocrine regulator of human endothelial cell growth.

Proliferation of endothelial cells is regulated through the autocrine production of growth factors and the expression of cognate surface receptors. In this study, we demonstrate that interleukin 1 (IL-1) is an inhibitor of endothelial growth in vitro and in vivo. IL-1 arrested growing, cultured endothelial cells in G1 phase; inhibition of proliferation was dose dependent and occurred in parallel with occupancy of endothelial surface IL-1 receptors. In an angiogenesis model, IL-1 could inhibit fibroblast growth factor-induced vessel formation. The autocrine nature of the IL-1 effect on endothelial proliferation was demonstrated by the observation that occupancy of cell-surface receptors by endogenous IL-1 depressed cell growth. The potential significance of this finding was emphasized by the detection of IL-1 in the native endothelium of human umbilical veins. A mechanism by which IL-1 may exert its inhibitory effect on endothelial cell growth was suggested by studies showing that IL-1 decreased the expression of high-affinity fibroblast growth factor binding sites on endothelium. These results point to a potentially important role of IL-1 in regulating blood vessel growth and suggest that autocrine production of inhibitory factors may be a mechanism controlling proliferation of normal cells.

Animals↗
PubMed1990

Immunocytochemical and ultrastructural changes of islet cells in rats treated long-term with cyclosporine at immunotherapeutic doses.

Daily cyclosporine doses of 10 mg/kg body weight for 21 days in Wistar rats cause impairment in glucose homeostasis and changes in the amount of immunostainable hormones and in the ultrastructure of the cells of the pancreatic islets. CsA induces hyperglycemia and reduced glucose tolerance, and causes a decrease in immunoreactive insulin and an increase of somatostatin and pancreatic polypeptide (PP) immunoreactivities, leaving glucagon immunoreactivity unaffected. Ultrastructurally, different degrees of dilation of rough endoplasmic reticulum cisternae and enlargement of Golgi apparatus can be observed in B cells, together with a pronounced reduction in the number of secretory granules. Nevertheless, there were no apparent morphological changes of the other cytoplasmic organelles, suggesting that the drug, besides a depression of protein synthesis, as previously stated, also induces a substantial defect in granulogenesis, probably due to impairment in the intracellular transport of the hormone from the sites of synthesis to the secretory granules. The B cell alterations are not accompanied by any sign of B cell degeneration or death. Non-B cells did not show any of the ultrastructural changes found in B cells and were similar to those of the control rats. The above findings indicate that CsA at immunotherapeutic doses causes impairment in the secretory processes of B cells specifically. An hypothesis on the mode of action of CsA on B cells is drawn.

Animals↗
PubMed1990

Morphological changes in rat pancreatic acinar cells induced by long-term treatment with cyclosporine and their reversal after withdrawal.

Cyclosporine (CsA), administered to rats at daily doses of 10 and 50 mg/kg body weight, for 21 days, influenced negatively the structures involved in the synthesis, storage and secretion of digestive enzymes in pancreatic acinar cells. A dose-related, significant reduction in basophilic cell regions, secretion granule content, and overall size of acinar cells was appreciable by light microscopy and morphometry. By electron microscopy, the acinar cells of the rats given 10 mg/kg/day CsA were similar to the controls, whereas with the higher dose most cells showed reduction in the size of nucleoli, increase in the number of lysosomes, and evidence of autophagy. In only a few cells was autophagy particularly severe and involved almost the entire cytoplasm. Nine weeks after withdrawal from CsA treatment, the structural recovery of acinal cells was complete, and features indicating enhanced protein synthesis and mitochondrial multiplication were observed by electron microscopy. In conclusion, prolonged administration of CsA to rats induces changes in the acinar cells indicating a depression of their activity, without substantial impairment in the viability of the most of them, even at high doses. This accounts for complete restoration of the acinar tissue upon withdrawal.

Animals↗
PubMed1990

Langerhans cells and mycosis fungoides--a critical overview of their pathogenic role in the disease.

Skin biopsies from seven patients with mycosis fungoides in various clinical stages (patches, plaques, nodules) were studied immunohistochemically and ultrastructurally, with the aim of investigating and quantifying the distribution of Langerhans cells and their relationships to mycosis cells. Our findings have revealed that in patches and plaques both Langerhans cells and mycosis cells were numerous in the epidermis. Notwithstanding this, in all the specimens examined, only one Langerhans cell forming close contact with a mycosis cell was detected. In the nodules, Langerhans cells and mycosis cells were sparse in the epidermis and no contacts were seen between them. Moreover, in all the patients studied, only a single Langerhans cell was found in the dermal infiltrate without any closely related mycosis cells. Conversely, numerous interdigitating cells have been found in the dermis of patches and plaques, often tightly adhering to mycosis cells. In the nodule, a few scattered interdigitating cells were seen, but often these had close contacts with neoplastic lymphoid cells. These findings indicate that close apposition between Langerhans cells and mycosis cells, which led previous authors to hypothesize a persistent stimulatory action of Langerhans cells on T lymphocytes, eventually leading to the malignant transformation of the latter, is unusual in mycosis fungoides. Therefore, if such a pathogenic role may be attributed to accessory cells in mycosis fungoides it is more probably exerted by dermal interdigitating cells and not by Langerhans cells, as previously proposed.

Humans↗
PubMed1990

Intermediate cell tumour of the pancreas in rat.

A malignant tumour of the rat pancreas with features of both acinar and endocrine cells is presented. This consisted of a continuous cytoplasmic mass with numerous dispersed nuclei and branches protruding from its borders invading the surrounding exocrine tissue. The most prominent characteristic of the tumour was the co-existence of zymogen and endocrine secretory granules and cytoplasmic organelles typical of both acinar and islet cells. Some hypotheses are put forward concerning the origin of the tumour and its vasculature.

Animals↗
PubMed1989

The exocrine pancreas in patients with hyperinsulinemic hypoglycemia. A morphometrical and ultrastructural study.

The exocrine pancreas has been studied morphometrically and ultrastructurally in 12 patients with insulin-producing tumors in comparison with control patients free from gastrointestinal or pancreatic diseases and with normal glucose homeostasis. Light microscopical examination and morphometrical data revealed that in the insulinoma-bearing patients acinar cells undergo a marked and significant decrease in zymogen granule content, together with a slight reduction in the mean cell area. Such changes were accompanied by ultrastructural features indicating increased production and exocytosis of zymogen granules. The findings concerning centroacinar/ductular cells are consistent with an increase in their number and mean cell area, and an enhancement of their functional activity. In synthesis, both the enzyme- and bicarbonate-secreting cells appear to be greatly stimulated in conditions of chronic hyperinsulinemic hypoglycemia owing to the presence of insulinomas.

Adenoma, Islet Cell↗
PubMed1989

A malignant tumor of the pancreas producing glucagonoma syndrome: immunocytochemistry and ultrastructure of liver metastases and comparison with the primary tumor.

In this study, liver metastases from a patient with a pancreatic glucagonoma producing the syndrome have been investigated histologically, ultrastructurally, and immunocytochemically. A comparison has also been made between the metastases and the primary pancreatic tumor investigated in a parallel study. In the metastatic tissue, glucagon-, pancreatic polypeptide (PP)-, and somatostatin-containing cells were found together with a majority of cells without any immunoreactivity. Glucagon-positive cells were much more numerous than PP- and somatostatin-immunoreactive cells. As in the primary tumor, double immunogold staining of ultrathin sections demonstrated the co-existence of glucagon and PP immunoreactivities in most of the granulated cells, but PP immunolabeling was often faint, so that it probably could not be revealed by the PAP method in light microscopical sections. Such a finding, together with the histological and ultrastructural features, is consistent with an ontogenic and phylogenetic primitiveness of the metastatic cell population.

Adenoma, Islet Cell↗