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Biomedical subjects

D Bani

Publications and source records attributed to D Bani.

68 records · Page 4Linked to original sources
PubMed1989

A malignant tumor of the pancreas producing glucagonoma syndrome: coexistence of glucagon and pancreatic polypeptide (PP) in the tumor cells.

A malignant tumor of the pancreas producing the glucagonoma syndrome and associated with high plasma levels of glucagon and pancreatic polypeptide was studied histologically, ultrastructurally, and immunocytochemically. The histologic and ultrastructural features were closely similar to those of previously reported malignant glucagonomas. However, immunolabeling with specific antisera revealed that, in addition to cells having only glucagon- or only pancreatic polypeptide-immunoreactivity, other cells were also present, showing a co-existence of both peptides. These findings indicate that the tumor contains a cell population with a phenotype similar to that of intestinal L-cells rather than to pancreatic A-cells.

Adenoma, Islet Cell↗
PubMed1989

Differentiation of interdigitating reticulum cells and Langerhans cells in the human skin with T-lymphoid infiltrate. An immunocytochemical and ultrastructural study.

The differentiation of two types of T-lymphocyte accessory cells, i.e., interdigitating reticulum cells and Langerhans cells, was studied immunocytochemically and ultrastructurally on cutaneous lesions from patients with mycosis fungoides, a neoplasm of mature T-lymphocytes. In such a condition the lymphoid infiltrate creates, adjacent to the epidermis, a microenvironment in the dermis similar to that of T-cell areas of lymphoid organs. Immunocytochemistry revealed that CD11c+ CD1a- putative monocytic cells co-exist with CD11c+ CD1a+ putative mature accessory cells. By electron microscopy, large numbers of interdigitating reticulum cells in the dermal infiltrate and Langerhans cells in the epidermis were found. Furthermore, monocytes were frequently observed, at times with cells showing intermediate features between monocytes and interdigitating reticulum cells on the one hand and Langerhans cells on the other. In the absence of proliferative phenomena of the above cells, it is conceivable that both interdigitating reticulum cells and Langerhans cells originate from locally migrated monocytes. A possible role of the local tissue micro-environment--namely the T-lymphoid microenvironment for interdigitating reticulum cells and the epidermal microenvironment for Langerhans cells--in inducing the differentiation of monocytes into the two kinds of accessory cells is proposed.

Cell Differentiation↗
PubMed1989

The endocrine pancreas in patients with insulinomas. An immunocytochemical and ultrastructural study of the nontumoral tissue with morphometrical evaluations.

The nontumoral endocrine pancreas was studied immunocytochemically and ultrastructurally in 12 patients with isolated insulinomas. Changes affecting hormone content and secretion of B-, A-, and D-cells were found in the islets of insulinoma-bearing patients when compared with controls, in terms of a significant decrease of the insulin-immunoreactive tissue areas and an increase in the glucagon- and somatostatin-immunoreactive ones. Conversely, only in two of the patients examined were PP-immunoreactive tissue areas augmented. Diffuse ducto-endocrine proliferation (nesidioblastosis) was also a common feature in the tumor-associated pancreas. Both morphometry and qualitative features revealed that islet cell hyperplasia occurs in the presence of insulinoma. Ultrastructural examination revealed that the functional activity of B-cells is substantially depressed in the insulinoma-bearing patients, whereas it is maintained or even enhanced in the other cell types. The islet content in immunoreactive insulin decreases along with duration of hypoglycemic symptoms. The present findings indicate that, in the presence of an insulinoma, the endocrine pancreas undergoes changes that can be regarded as an adaptive response to the chronic excess of insulin and are possibly responsible for the patients' postoperative clinical course.

Adenoma, Islet Cell↗
PubMed1988

Interdigitating reticulum cells in the dermal infiltrate of mycosis fungoides. An ultrastructural and immunohistochemical study.

In order to provide insight into the role of accessory cells in lymphoproliferative neoplasms, 7 cases of mycosis fungoides at various clinical stages--patches, plaques and nodules--were studied ultrastructurally and immunohistochemically. The aim was to establish whether interdigitating reticulum cells are a constant finding in the dermal infiltrate. Their possible relationships with mycosic cells were also investigated. This study revealed that interdigitating reticulum cells were present in all the skin lesions examined, were present in considerable number in the patches and plaques and became sparse in the nodules. Furthermore, in the lesions at various clinical stages these cells showed varying ultrastructural features, probably related to different developmental stages. The close contacts between interdigitating reticulum cells and mycosic cells, the expression of antigenic markers of activation by mycosic cells and the morphological and immunohistochemical signs of progressive de-differentiation of mycosic cells in the more advanced stages suggest that interdigitating reticulum cells are involved in stimulating proliferation and--possibly--neoplastic progression of mycosic cells. A role for the T-cell microenvironment created in the dermis by lymphoid infiltrate in inducing the differentiation of interdigitating reticulum cells from their precursors is proposed.

Adult↗
PubMed1986

The effects of relaxin on the mouse mammary gland. II. The epithelium.

The study deals with the effects of relaxin (RLX) on epithelial cells of the mammary ducts in ovariectomized virgin mice, evaluated by light and electron microscopy. One microgram (3 GPU) pure porcine RLX (NIH-RXN-P1) was administered either alone or after pretreatment with estrogen. The possibility of a non specific binding of RLX to insulin receptors on the mammary epithelial cells was excluded by comparing the effects of the administration of the two hormones at the same doses. Our findings indicate that RLX greatly enhances the growth of the mammary duct epithelial cells, as demonstrated by the extensive branching and elongation of the ducts, and by the rather frequent occurrence of mitoses in the epithelial cell precursors and of the intermediate stages of their differentiation into mature duct cells. Three GPU RLX, administered alone, had only an inconstant and slight effect on the epithelial cell growth, a priming dose with estrogen being necessary to obtain the highest levels of duct growth. Moreover the treatment with 1 microgram of insulin for the same time showed a very inconstant and lesser effect in comparison to RLX. We did not find any evidence of alveolar maturation and milk secretion in the RLX-treated mice. The recognition of a stimulatory role of RLX on the proliferation and growth of the mammary duct epithelium may be of a certain importance in the understanding of hormonal control of the mammary development in physiological conditions and the genesis and growth of mammary neoplasms.

Animals↗
PubMed1985

Nesidioblastosis and intermediate cells in the pancreas of patients with hyperinsulinemic hypoglycemia.

The pancreases of three patients with hyperinsulinemic hypoglycemia were studied: one of these patients was a child born to a diabetic mother, the other two were adults with insulinomas. All the patients had nesidioblastosis, namely the presence of a number of pancreatic endocrine cells spread throughout the exocrine tissue singly or clustered in small groups. In the hypoglycemic child the endocrine cells scattered in the acinar tissue were mostly A cells, whereas in the patients with insulinomas both A and B cells were found with a similar frequency. Intermediate cells (acinar-islet cells) were found in all the cases. These findings suggest that nesidioblastosis and the de novo formation of intermediate cells are associated phenomena. Possible mechanisms for the genesis of the islet cell types spread throughout the exocrine parenchyma and of the intermediate cells are discussed and their possible clinical implications are suggested.

Adenoma, Islet Cell↗
PubMed1985

Nesidioblastosis and islet cell changes related to endogenous hypergastrinemia.

The endocrine pancreas from four hypergastrinemic patients with recurrent peptic ulceration has been studied by light and electron microscopy. Greatly increased numbers of ducts and centroacinar cells have been observed associated with a striking increase in the number of islets and endocrine cells scattered in the acinar tissue (nesidioblastosis). The islet cells scattered throughout the exocrine parenchyma are of all the known islet cell types, with a prevalence of B and especially A cells. Many islets, probably formed de novo, are of a considerable size, have irregular contours and are in close apposition to centroacinar cells and ducts. The degree of nesidioblastosis and islet hyperplasia does not seem to be related to the plasma gastrin levels. Cytological changes have also been found in the islet cells of the hypergastrinemic patients compared with controls. These changes mainly affect the B cells and consist of a striking decrease in the number of mature secretory granules associated with a fairly extended ergastoplasm and Golgi apparatus and with a relevant increase in the number of immature granules. In two of the four patients examined, who had more severe hypergastrinemia, cytological signs of enhanced secretion are also recognized in A cells. The features indicating hypersecretion of B and A cells seem to be related to the plasma gastrin levels. The above findings indicate that chronic endogenous hypergastrinemia promotes proliferation and differentiation of islet cells and stimulates the secretory function of B cells and, to a lesser extent, of A cells, thus providing evidence for a trophic and secretagogue action of gastrin on the endocrine pancreas.

Female↗
PubMed1985

Effects of relaxin on the mouse mammary gland. I. The myoepithelial cells.

Myoepithelial cells (MEC) were studied in the mammary gland of ovariectomized virgin mice without any hormonal treatment and following the administration of either estrogen or estrogen plus relaxin (either purified porcine relaxin standard or partially purified human relaxin extracted from decidua). Changes in MEC lineage were observed at both the light and electron microscopic levels in the hormonally treated animals as compared with the untreated controls. After 7 days of estrogen administration, there was a moderate elongation and branching of ducts. At the growing tips and buds undifferentiated precursors and promyoepithelial cells at various stages of their differentiation were seen with some frequency. After relaxin administration (18-20 hrs) to mice pre-treated with estrogen, branching and elongation of ducts were greatly increased as compared to mice treated with estrogen alone. At the growing points the ducts showed multi-layered walls and undifferentiated precursors were quite frequently found with some mitotic figures. Moreover several promyoepithelial cells at various stages of differentiation were observed. These findings, which were similar after administration of the two different relaxin preparations, indicate a high rate of proliferation and differentiation of MEC in these experimental conditions and hence suggest that relaxin greatly enhances the de novo formation of MEC. A stimulatory effect of relaxin on MEC growth is discussed in terms of a possible role of this hormone in the genesis of benign and malignant neoplasms of the mammary gland, in which MEC proliferation can be recognized.

Animals↗
PubMed1985

New views on the identification of the various cell types in the pancreatic islets of the rat. An ultrastructural and morphometrical study.

Islets of Langerhans taken from different parts of the pancreas have been studied ultrastructurally in adult rats. Five different islet cell types were identified in each islet with the aid of morphometrical analysis of their specific secretory granules. Previous immunohistochemical findings concerning the amount and location of insulin-, glucagon-, somatostatin- and pancreatic-polypeptide-containing cells and their ultrastructurally recognizable counterparts were compared, and it was possible to identify four main islet cell types with the electron microscope. Moreover, cells quite similar to the enterochromaffine cells described elsewhere in the exocrine pancreas and in the gastrointestinal tract were found to normally occur in the pancreatic islets of the rat.

Animals↗
PubMed1984

The exocrine pancreas of patients with WDHA syndrome. A light and electron microscopical study.

The exocrine pancreas of two patients with WDHA syndrome was studied by light and electron microscopy and by morphometrical methods. Compared to the controls, centroacinar and ductular cells were increased in number and richer in organelles, and acinar cells were markedly degranulated with well-developed ergastoplasm and Golgi apparatus. These findings suggest enhanced secretion of bicarbonate and enzymes in patients with WDHA syndrome. These results are discussed in the light of the complex metabolic and endocrine conditions occurring in this syndrome.

Achlorhydria↗
PubMedDate not supplied

Relaxin, a potent microcirculatory effector, is not angiogenic.

The ability of relaxin (RLX), which is a potent microcirculatory effector in many species including the rat, to induce de novo angiogenesis in vascularized mammalian tissue was tested using the rat mesenteric-window angiogenesis assay. RLX was administered intraperitoneally on days 1-5 at doses of 0.33, 3.3 and 33 nM. Controls received the vehicle by the same route. Groups of animals were sacrificed at the end of the 1st, 2nd and 3rd weeks. Using computer-aided microscopic morphometry including image analysis, the response was quantified by sensitive, technically independent, highly reproducible methods in terms of the vascularized area (VA), a measure of microvascular spatial extension, and the microvascular length (MVL), a measure of microvascular density. The total MVL was computed from VA x MVL. The results obtained show that RLX did not cause significant changes in any of the variables tested, regardless of dose and observation time. These findings indicate that RLX is apparently unable to mediate significant de novo angiogenesis in the system used in contrast to previously tested angiogens such as basic fibroblast growth factor, vascular endothelial growth factor, isoform 165, and tumor necrosis factor-alpha. In previous studies, RLX has been shown to exert antitumor activity on breast cancer cells in vitro. In the search for a possible role for RLX as an anticancer agent in vivo, it is important to know that this peptide is not angiogenic, since de novo angiogenesis is known to be a prerequisite for tumor growth and metastatic spread.

Animals↗