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  • 1
    ISSN: 1432-0428
    Keywords: Pancreas ; endocrine cells ; morphometry ; development ; Beckwith-Wiedemann syndrome ; immunofluorescence ; pancreatic hormones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The endocrine cell content of the pancreas of two cases of Beckwith-Wiedemann syndrome with islet cell adenomatosis were studied. Insulin, glucagon, somatostatin and pancreatic polypeptide cells were evaluated qualitatively and quantitatively with the indirect immunofluorescence method and morphometry was used to establish the volume density of the four endocrine cell populations. This evaluation showed a marked increase of insulin and glucagon cells and a lesser augmentation of pancreatic polypeptide cells and somatostatin cells. However, the percent of somatostatin cells was decreased in comparison with controls. Qualitatively, the two pancreas were characterized by the lack of segregation of glucagon and pancreatic polypeptide cells to distinct parts of the gland, with each cell type being abundant in the pancreatic region in which they are normally very sparse. The marked increase of endocrine cells often took the form of giant islet-like structures formed by smaller subunits; however, despite this increase, the distribution of insulin cells respected the normal pattern, i.e. clusters of B cells surrounded by non-B cells. These findings indicate that besides the proliferation of pancreatic endocrine cells maintaining a normal topographical distribution of B versus non-B cells, the pancreas of patients with the Beckwith-Wiedemann syndrome may have undergone abnormal development with a consequent lack of segregation of glucagon and pancreatic polypeptide cells to different parts of the gland.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0428
    Keywords: Chinese hamster ; Cricetulus griseus ; endocrine pancreas ; islet of Langerhans ; A-cells ; B-cells ; D-cells ; spontaneous diabetes ; nuclear pores ; plasma membrane ; membrane-associated particles ; glycogen ; ultrastructure ; electron microscopy ; freeze-etching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The nuclear and plasma membranes of islet cells from non-glycosuric and diabetic Chinese hamsters were examined by freeze-etching. The B-cells of diabetic animals presented a slight increase in the number of nuclear pores and marked alterations in the number, size and distribution of membrane-associated particles in the plasma membrane. In A-cells, identified by the presence of characteristic bundles of coarse filaments in the perinuclear region, a definite increase in the number of nuclear pores was found in the most severely diabetic animals. These preliminary findings point to alterations in the membrane systems as possible determinants for the abnormalities of islet function in diabetes mellitus.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0428
    Keywords: Diabetes ; EMC-virus ; islet cells ; immunofluorescence ; morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The endocrine cell populations of pancreatic islets in encephalomyocarditis (EMC)-virus infected mice were assessed quantitatively by immunofluorescence using specific antisera against 4 islet hormones. A marked reduction of the volume of insulin-containing (B-) cells (up to one tenth of control values) was observed at all stages studied in the hyperglycaemic mice. This was accompanied by the inversion of the normal ratio between B- and non B-cells. The volume of the latter cell types was also modified at different time points after infection: glucagon-cells were augmented 14 days after infection; PP-cells were decreased 2–3 days and 21 days after infection; somatostatin-cells decreased to one-fourth of control values in hyperglycaemic animals 21 days after infection. The latter results suggest that non B-cells are also involved in islet reaction to virus infection.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 16 (1979), S. 135-138 
    ISSN: 1432-0428
    Keywords: Membrane ; cell coat ; lectin-binding sites ; exocytosis ; cell web ; B-cell ; islet of Langerhans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using ferritin-labelledRicinus communis agglutinin to detect lectin-binding sites of the pancreatic B-cell surface, we show that limited regions of the plasma membrane are deprived of lectin-binding sites over marginated secretory granules. Such deprived regions increased during glucose stimulation of B-cells in monolayer culture: 56±8 of them were found in high (300 mg/100 ml) glucose as compared to only 27±5 in low (50 mg/100ml) glucose (p〈0.005). In addition, non-membrane, intracytoplasmic bridges were detected between the plasma membrane and the membrane of the marginated granule suggesting the involvement of cell web components in promoting the change in surface labelling.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0428
    Keywords: Pancreas ; islets of Langerhans ; insulin ; glucagon ; somatostatin ; pancreatic polypeptide ; immunohistochemistry ; embryology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Systematic sampling of human necropsy pancreases has revealed that pancreatic polypeptide (PP) cells are not distributed equally in the gland. PP-cells are the most abundant cell type in the posterior part of the pancreatic head while they are scarce or absent in the remainder of the gland. The PP-rich part of the head can be separated by blunt dissection from the pancreas as a discrete lobe. This lobe probably originates from the ventral pancreatic bud during embryogenesis. A quantitative study of the immunofluorescent endocrine cell types (insulin, glucagon, somatostatin and pancreatic polypeptide cells) in PP-rich and PP-poor regions of pancreases in 8 subjects with ages ranging from 33 fetal weeks to 80 years, showed that the proportions of the cell types were different in youngs and adults.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0428
    Keywords: Insulin receptor ; internalization ; endocytosis ; hepatocytes ; binding ; insulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary By quantitative electron microscopic autoradiographic technique, we have previously shown that125I-insulin initially localizes to the plasma membrane of isolated rat hepatocytes and is subsequently internalized in a limited region of the peripheral cytoplasm. In the present study, we have shown that when cells are incubated at 20 °C, steady state binding is reached by 60 minutes and maintained up until 120 minutes of incubation while at 37 °C steady state binding is reached by 10 minutes and maintained for 30 minutes. Under both of these conditions, internalization of the labelled material occurs as a constant function of the binding. These data suggest that under normal conditions the binding of the ligand is an important rate limiting determinant of the internalization process.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0428
    Keywords: Myelin membrane ; freeze-fracture ; streptozotocin diabetic rats ; insulin ; myoinositol ; nerve conduction velocity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Replicas of the freeze-fracture surfaces of the internodal myelin membranes of large sciatic nerve fibres from normal and diabetic rats were compared by quantitative electron microscopy. The internodal myelin of the diabetics was examined 14 days after streptozotocin (70 mg/kg IV) induced persistent hyperglycaemia, conditions under which sciatic motor nerve conduction velocity (MNCV) is consistently decreased by 20%. The number of intramembranous particles per unit area of both the P-face and the E-face of the internodal myelin membrane was significantly decreased in the diabetics. This alteration in the structure of the internodal myelin membrane was not found in large sciatic nerve fibres from diabetic rats treated with insulin from day 3 through 14, or from diabetic rats fed a diet containing 1% myoinositol; these are conditions under which the development of decreased sciatic MNCV is prevented or ameliorated. An alteration in internodal myelin structure occurs in acute streptozotocin diabetes which may explain the associated decreased sciatic MNCV.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 18 (1980), S. 263-274 
    ISSN: 1432-0428
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0428
    Keywords: B-cell microtubules ; spontaneous diabetes ; spiny mice (Acomys cahirinus) ; DBM mice ; isolated islets ; vincristine-induced crystals ; electron microscopy ; morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The pancreatic B-cell contains microtubules, which are thought to participate in the process of insulin release. In order to disclose a possible abnormality of this B-cell microtubular system in animals with islet dysfunction, isolated islets from normal rats and mice, as well as from diabetic mutant mice (DBM mice) and from spiny mice (Acomys cahirinus) were incubated in the presence of vincristine, which causes the precipitation of the microtubular protein into paracrystalline deposits. Ultrastructural examination of the islets indicated that the volume-density of vincristine-induced deposits was markedly reduced in B-cells of spiny mice, when compared to that found in normal rats and mice and DBM mice. Exposure of the islets from spiny mice to a high glucose concentration, concomittantly to vincristine, caused a further reduction in vincristine-induced crystals content of the B-cell. It is speculated that an impairment of the B-cell microtubular system may account for the deficiency of insulin release found in spiny mice.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0428
    Keywords: Immuno-fluorescence ; gastro-intestinal tract ; somatostatin ; gastrin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Evidence is presented that somatostatin-containing cells are present in the gastro-intestinal tract of the dog. Thus immuno-fluorescent cells were detected by the use of antiserum to cyclic somatostatin. These cells were mainly encountered in the antral mucosa and in the neighbourhood of gastrin-producing cells. No cross reaction was observed between gastrin and somatostatin. It is suggested that locally produced somatostatin controls gastrin secretion, and, more generally, that somatostatin-containing cells, multifocally distributed, modulates secretion of a large number of glands.
    Type of Medium: Electronic Resource
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