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  • 1
    Electronic Resource
    Electronic Resource
    Localisation of islet amyloid polypeptide and its carboxy terminal flanking peptide in islets of diabetic man and monkey (1991)
    Springer
    Diabetologia 34 (1991), S. 449-451 
    Details
    ISSN: 1432-0428
    Keywords: Islet amyloid polypeptide ; islet amyloid ; Type 2 (non-insulin-dependent) diabetes mellitus ; Beta cell ; pancreas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Islet amyloid polypeptide is a normal constituent of islet Beta cells and is derived from a larger precursor by removal of flanking peptides at the carboxy (C) and amino (N) terminals. The role of these flanking peptides in the formation of amyloid in Type 2 (non-insulin-dependent) diabetes mellitus and in insulinomas is unknown. The C-terminal flanking peptide of islet amyloid polypeptide was localised by immunocytochemistry in human and monkey pancreatic islets from Type 2 diabetic and non-diabetic individuals by use of specific polyclonal antisera. Immunoreactivity for the C-terminal peptide was found in insulincontaining cells in both diabetic and non-diabetic tissue: no antibody binding was detected in islet amyloid of Type 2 diabetic man or of monkeys although a positive reaction occurred with antisera for islet amyloid polypeptide. The C-terminal peptide was localised by immunogold electron microscopy in the insulin granules in both diabetic and nondiabetic individuals but, unlike islet amyloid polypeptide, was not detected in lysosomes. The absence of immunoreactivity for the C-terminal peptide in amyloid suggests that incomplete cleavage of this flanking peptide from islet amyloid polypeptide is not a factor in the formation of islet amyloid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403186
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Chronic overproduction of islet amyloid polypeptide/amylin in transgenic mice: lysosomal localization of human islet amyloid polypeptide and lack of marked hyperglycaemia or hyperinsulinaemia (1993)
    Springer
    Diabetologia 36 (1993), S. 1258-1265 
    Details
    ISSN: 1432-0428
    Keywords: Islet amyloid polypeptide ; amylin ; transgenic mouse ; islet beta cell ; islet amyloid ; glucose metabolism ; insulin resistance ; Type 2 (non-insulin-dependent) diabetes mellitus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Type 2 (non-insulin-dependent) diabetes mellitus is characterised by hyperglycaemia, peripheral insulin resistance, impaired insulin secretion and pancreatic islet amyloid formation. The major constituent of islet amyloid is islet amyloid polypeptide (amylin). Islet amyloid polypeptide is synthesized by islet beta cells and co-secreted with insulin. The ability of islet amyloid polypeptide to form amyloid fibrils is related to its species-specific amino acid sequence. Islet amyloid associated with diabetes is only found in man, monkeys, cats and racoons. Pharmacological doses of islet amyloid polypeptide have been shown to inhibit insulin secretion as well as insulin action on peripheral tissues (insulin resistance). To examine the role of islet amyloid polypeptide in the pathogenesis of Type 2 diabetes, we have generated transgenic mice with the gene encoding either human islet amyloid polypeptide (which can form amyloid) or rat islet amyloid polypeptide, under control of an insulin promoter. Transgenic islet amyloid polypeptide mRNA was detected in the pancreas in all transgenic mice. Plasma islet amyloid polypeptide levels were significantly elevated (up to 15-fold) in three out of five transgenic lines, but elevated glucose levels, hyperinsulinaemia and obesity were not observed. This suggests that insulin resistance is not induced by chronic hypersecretion of islet amyloid polypeptide. Islet amyloid polypeptide immunoreactivity was localized to beta-cell secretory granules in all mice. Islet amyloid polypeptide immunoreactivity in beta-cell lysosomes was seen only in mice with the human islet amyloid polypeptide gene, as in human beta cells, and might represent an initial step in intracellular formation of amyloid fibrils. These transgenic mice provide a unique model with which to examine the physiological function of islet amyloid polypeptide and to study intracellular and extracellular handling of human islet amyloid polypeptide in pancreatic islets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400803
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Development of microglia and macrophages in the postnatal rat pituitary (1996)
    Springer
    Cell & tissue research 286 (1996), S. 347-355 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Microglia ; Macrophages ; Pituitary ; Neurohypophysis ; Adenohypophysis ; Phagocytosis ; Perivascular space ; Rat (Long Evans)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Microglia and macrophages, immunolabelled with F4/80 (which binds a 160-kDa plasmalemmal glycoprotein) and OX-42 (which labels the complement type 3 receptor, CR3), were identified in the neuro- and adenohypophyses, respectively, of postnatal rats from day 1 to adulthood. In the neurohypophysis, the numerical density (cells/mm2) of microglia increased from postnatal day 1 to day 7 but was then unchanged from the adult density. In the adenohypophysis, the numerical density of macrophages increased from postnatal day 1 to day 21. The increasing size of the pituitary meant that the total number of such cells increased rapidly in the neurohypophysis up to day 14, but was then essentially unchanged; in the adenohypophysis macrophages increased in proportion to the increasing size of the gland up to day 21. Proliferation of the mononuclear cells was analysed by the immunodetection of bromodeoxyuridine incorporation into the nuclei of microglia and macrophages. F4/80-immunoreactive cells incorporating bromodeoxyuridine were found on all the postnatal days studied. The proportion of such cells in the neurohypophysis was high from postnatal day 1 to day 14 and in the adenohypophysis was maximal on day 14, decreasing in both parts of the pituitary by day 21. The estimated total number of proliferating cells was maximal in both parts of the pituitary on day 14. In both parts, OX-42-immunoreactive cells were less numerous than F4/80-immunoreactive cells up to postnatal day 14; CR3 expression may therefore be associated with maturation of these cells. Neurohypophysial microglia increased in size to postnatal day 7, consistent with the assumption of a ’compact’ microglial morphology; adenohypophysial macrophages did not change in size over the postnatal period. Throughout the period studied, neurohypophysial microglia were significantly more densely distributed and larger in size than adenohypophysial macrophages. Neurohypophysial microglia phagocytose terminals of neurosecretory neurons from day 7, concurrent with the development of a distinct perivascular space. In the adenohypophysis, the perivascular space was present from birth and macrophages were not phagocytic. There are, therefore, considerable differences in the density, morphology and activity between the populations of myelomonocytic cells in the postnatal rat neuro- and adenohypophyses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050704
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Immunophenotypic evidence for distinct populations of microglia in the rat hypothalamo-neurohypophysial system (1995)
    Springer
    Cell & tissue research 280 (1995), S. 665-673 
    Details
    ISSN: 1432-0878
    Keywords: Microglia ; Hypothalamo-neurohypophysial system ; Antigen-presenting cells ; Blood-brain barrier ; Phagocytosis ; Immunohistochemistry ; Rat (Long Evans)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The morphology, distribution and immunophenotype of microglia throughout the adult rat hypothalamo-neurohypophysial system was examined. Four macrophage-associated antibodies (OX-42, F4/80, ED1 and ED2) were used; the expression of major histocompatibility complex antigens was investigated by use of antibodies against OX-6, OX-17 (MHC class II) and OX-18 (MHC class I). Three distinct types of microglia were identified. The first was located in the magnocellular nuclei; these ‘radially branched’ (‘ramified’) microglia had round cell bodies and long branched processes, and were strongly immunoreactive only for OX-42. The second was located outside the blood-brain barrier in the median eminence, pituitary stalk and neurohypophysis often close to blood vessels; these ‘compact’ microglia had irregular cell bodies and shorter processes, and were strongly labelled by OX-42 and F4/80, weakly labelled by OX-18, and generally unlabelled by ED1, ED2, OX-6 and OX-17. The third type was found in small numbers throughout the system at the surface of the neurvous tissue or around blood vessels; these ‘perivascular’ microglia were elongated cells with no branching processes, and were strongly labelled by ED1, ED2, OX-18, OX-6, OX-17 and F4/80 antibodies but showed variable OX-42 immunoreactivity. Cells in a perivascular location were heterogeneous with respect to their immunophenotype. The presence in the normal adult rat hypothalamo-neurohypophysial system of MHC class-II molecules (OX-6 and OX-17) on a sub-set of perivascular microglia suggests that these cells are capable of presenting antigen to T lymphocytes. The microglia, which lie on either side of the blood-brain barrier, are well placed to facilitate interaction between the immune and neuroendocrine systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318369
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Immunophenotypic evidence for distinct populations of microglia in the rat hypothalamo-neurohypophysial system (1995)
    Springer
    Cell & tissue research 280 (1995), S. 665-673 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Microglia ; Hypothalamo-neurohypophysial system ; Antigen-presenting cells ; Blood-brain barrier ; Phagocytosis ; Immunohistochemistry ; Rat (Long Evans)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The morphology, distribution and immunophenotype of microglia throughout the adult rat hypo- thalamo-neurohypophysial system was examined. Four macrophage-associated antibodies (OX-42, F4/80, ED1 and ED2) were used; the expression of major histocompatibility complex antigens was investigated by use of antibodies against OX-6, OX-17 (MHC class II) and OX-18 (MHC class I). Three distinct types of microglia were identified. The first was located in the magnocellular nuclei; these ’radially branched’ (’ramified’) microglia had round cell bodies and long branched processes, and were strongly immunoreactive only for OX-42. The second was located outside the blood-brain barrier in the median eminence, pituitary stalk and neurohypophysis often close to blood vessels; these ’compact’ microglia had irregular cell bodies and shorter processes, and were strongly labelled by OX-42 and F4/80, weakly labelled by OX-18, and generally unlabelled by ED1, ED2, OX-6 and OX-17. The third type was found in small numbers throughout the system at the surface of the nervous tissue or around blood vessels; these ’perivascular’ microglia were elongated cells with no branching processes, and were strongly labelled by ED1, ED2, OX-18, OX-6, OX-17 and F4/80 antibodies but showed variable OX-42 immunoreactivity. Cells in a perivascular location were heterogeneous with respect to their immunophenotype. The presence in the normal adult rat hypothalamo-neurohypophysial system of MHC class-II molecules (OX-6 and OX-17) on a sub-set of perivascular microglia suggests that these cells are capable of presenting antigen to T lymphocytes. The microglia, which lie on either side of the blood-brain barrier, are well placed to facilitate interaction between the immune and neuroendocrine systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318369
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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