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  • Electronic Resource  (3)
  • 1990-1994  (3)
  • Chiral separation  (2)
  • Diabetes mellitus  (1)
  • 1
    ISSN: 1432-2307
    Keywords: Islet amyloid polypeptide ; Insulinoma ; Pancreatic islet ; Diabetes mellitus ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Amyloid deposition is a common pathological feature in insulinoma and in the islets of the pancreas in type-2 diabetic patients. The present immunohisto-chemical study revealed that normal B-cells, insulinoma, and amyloid deposits in insulinoma and diabetic pancreatic islets were commonly immunoreactive with antiserum to C-terminal synthetic tetradecapeptide of human islet amyloid polypeptide (IAPP) (24–37). Amyloid fibrils in insulinoma were also positive to IAPP by immunoelectron microscopy. A high level of IAPP was detected in the plasma and tissue of a insulinoma patient by radioimmunoassay suggesting that amyloid deposition in insulinoma is due to overproduction of IAPP. Amyloid deposits immunoreactive to IAPP were also seen in all diabetic pancreatic islets, but in no non-diabetic islets. There was much amyloid deposition in the islets of severe diabetics, whose B-cells demonstrated decreased immunoreactivities for IAPP and insulin. The IAPP content of the pancreas was 649.0 and 847.7 pg/mg wet weight in each of two diabetic patients, and 1034.6 and 1447.7 pg/mg wet weight in two non-diabetic patients. The present study revealed that IAPP is a bioactive peptide secreted from islet B-cells and are amyloidogenic peptide concerned in diabetogenensis and/or the progression of type-2 diabetes mellitus.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chiral separation ; Alpha 1-acid glycoprotein-bonded column ; Propranolol ; Propranolol ester derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention, enantionselectivity and enantiomeric elution order of racemic propranolol (PP) and its ester derivatives (O-acetyl,-propionyl,-butyrul and-valeryl PP) on an α1-acid glycoprotein (AGP)-bonded column have been investigated by changing eluent composition (eluent pH, buffer concentration, type and content of organic modifier). The retention of these cationic solutes, PP and its ester derivatives, was influenced by eluent pH, ionic strength and organic modifier content. The enantioselectivity was dependent on eluent pH and type of organic modifier. Reversal of the enantiomeric elution order of ester derivatives of PP (O-propionyl-butyryl) and-valeryl PP) occurred around eluent pH 6–7. These results suggst that chiral recognition or binding properties may be altered by the change in eluent composition, espeically eluent pH and type of organic modifier.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ovomucoid-bonded silica ; Chiral separation ; Propranolol ; Propranolol ester derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention, enantioselectivity and enantiomeric elution order of racemic propranolol (PP) and its ester derivatives (O-acetyl,-propyl,-butyl and-valeryl PP) on an ovomucoid-bonded silica column have been investigated with respect to pH, ionic strength and organic modifier. For these cationic solutes, an increase in the organic modifier content and/or a decrease in the pH result in a decreased retention of both enantiomers. Enantioselectivity of the ester derivatives was higher than of underivated PP. The enantiomeric elution order was (S)/(R) for PP and (R)/(S) for the four ester derivatives, when ethanol or 2-propanol was used as the organic modifier. When methanol or acetonitrile was used as the organic modifier, inversion of the enantiomeric elution order was observed for O-valeryl PP with the use of methanol and for PP and O-propyl PP with acetonitrile. These results suggest that at least two chiral binding- or recognitionsites are present in a protein molecule and/or conformational changes occur in the chiral binding- or recognition-site(s) of the protein molecule bonded to a silica matrix.
    Type of Medium: Electronic Resource
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