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  • 1
    ISSN: 1432-0428
    Keywords: Keywords Advanced glycation end products ; blood retinal barrier ; diabetic retinopathy ; Ne-(carboxymethyl)lysine ; vascular endothelial growth factor.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Both advanced glycation end products and vascular endothelial growth factor are believed to play a role in the pathogenesis of diabetic retinopathy. It is known that vascular endothelial growth factor causes retinal neovascularization and a breakdown of the blood-retinal barrier; how advanced glycation end products affect the retina, however, remains largely unclear. The substance Ne-(carboxymethyl)lysine is a major immunologic epitope, i. e. a dominant advanced glycation end products antigen. We generated an anti-Ne-(carboxymethyl)lysine antibody to investigate the relationship between the localization of advanced glycation end products and that of vascular endothelial growth factor in 27 human diabetic retinas by immunohistochemistry. Nine control retinas were also examined. In all 27 diabetic retinas, Ne-(carboxymethyl)lysine was located in the thickened vascular wall. In 19 of the 27 retinas, strand-shaped Ne-(carboxymethyl)lysine immunoreactivity was also observed around the vessels. In all 27 diabetic retinas, vascular endothelial growth factor revealed a distribution pattern similar to that of Ne-(carboxymethyl)lysine. Vascular endothelial growth factor was also located in the vascular wall and in the perivascular area. Neither Ne-(carboxymethyl)lysine nor vascular endothelial growth factor immunoreactivity was detected in the 9 control retinas. Vessels with positive immunoreactivity for Ne-(carboxymethyl)lysine and/or vascular endothelial growth factor were counted. A general association was noted between accumulation of Ne-(carboxymethyl)lysine and expression of vascular endothelial growth factor in the eyes with non-proliferative diabetic retinopathy (p 〈 0.01) and proliferative diabetic retinopathy (p 〈 0.05). [Diabetologia (1997) 40: 764–769]
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0428
    Keywords: Keywords AGE ; carboxymethyllysine ; diabetes ; peripheral nerve ; neuropathy ; immunohistochemistry ; electron microscopy.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present study was designed to elucidate in situ distribution of advanced glycation end-products (AGE) in human peripheral nerve and whether the reaction products were excessive in the diabetic condition. For the detection of AGE, immunoperoxidase staining was undertaken on peripheral nerve samples obtained from 5 non-insulin-dependent diabetic patients and 5 non-diabetic control subjects. The anti-AGE antibody used in this study contained an epitope against Nɛ-carboxymethyllysine. Light microscopically, AGE localized in the perineurium, endothelial cells and pericytes of endoneurial microvessels as well as myelinated and unmyelinated fibers. At the submicroscopic level, AGE deposition appeared focally as irregular aggregates in the cytoplasm of endothelial cells, pericytes, axoplasm and Schwann cells of both myelinated and unmyelinated fibers. Interstitial collagens, basement membranes of the perineurium also reacted with this antibody. The AGE depositions were detected in both control and diabetic nerves, but were more intense in the latter. The excessive AGE deposition correlated with a reduction in myelinated fiber density. However, the localization of AGE was not directly associated with degeneration of nerve fibers and the link between AGE deposition and nerve fiber degeneration is yet to be determined. The present study thus demonstrated the excessive deposition of intra- and extracellular AGE in human diabetic peripheral nerve and strengthened the contention that the enhanced glycation may play a role in the development of diabetic neuropathy. [Diabetologia (1997) 40: 1380–1387]
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0428
    Keywords: Keywords Advanced glycation end products ; aminoguanidine ; nitric oxide ; diabetic nephropathy.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims/hypothesis. Advanced glycation end products are believed to contribute to diabetic microvascular complications by inducing glomerular damage but their role has not been fully clarified. In this study, we explain their central role in the induction of inducible nitric oxide synthase and production of nitric oxide (NO) in streptozotocin-induced diabetic rat glomeruli. Methods. Localization of carboxymethyllysine, which is one of the chemical components of advanced glycation end products, glomerular expression of inducible nitric oxide synthase and urinary excretion and glomerular production of NO2 –/NO3 – were examined at 0, 26, 51, and 52 weeks after the induction of diabetes. Therapeutic effects of aminoguanidine were also examined. Results. Carboxymethyllysine was detected in the mesangial area in glomeruli and it progressively accumulated during 52 weeks of observation. Immunohistochemistry and hybridization studies in situ showed that the number of inducible nitric oxide synthase-positive cells was notably increased in diabetic rat glomeruli at 52 weeks. Further, this augmented expression paralleled intraglomerular expression of TNF-α and NO2 –/NO3 – in diabetic rat glomeruli. Treatment with aminoguanidine reduced the expression of TNF-α, inducible nitric oxide synthase and intraglomerular NO2 –/NO3 – production. It also ameliorated proteinuria in diabetic rats. Conclusion/interpretation. This study showed that carboxymethyllysine possibly enhances the expression of inducible nitric oxide synthase by stimulating the expression of TNF-α in diabetic rat glomeruli. The carboxymethyllysine-cytokine-NO sequence pathway could be one of the major mechanisms in the development of diabetic nephropathy. [Diabetologia (1999) 42: 878–886]
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0533
    Keywords: Key words Amyotrophic lateral sclerosis ; Imidazolone ; Nɛ-carboxymethyl-lysine ; Pyrraline ; Superoxide dismutase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To assess a role for oxidative stress in the pathogenesis of amyotrophic lateral sclerosis (ALS), we analyzed the immunohistochemical localization of 8-hydroxy-2′-deoxyguanosine (OHdG) as a nucleic acid oxidation product, acrolein-protein adduct and 4-hydroxy-2-nonenal (HNE)-protein adduct as lipid peroxidation products, N ɛ-carboxymethyl-lysine (CML) as a lipid peroxidation or protein glycoxidation product, pentosidine as a protein glycoxidation product, and imidazolone and pyrraline as nonoxidative protein glycation products in the spinal cord of three familial ALS patients with superoxide dismutase-1 (SOD1) A4V mutation, six sporadic ALS patients, and six age-matched control individuals. The spinal cord sections of the control cases did not show any distinct immunoreactivities for these examined products. In the familial ALS cases, intense immunoreactivities for pyrraline and CML were confined to the characteristic Lewy body-like hyaline inclusions, and imidazolone immunoreactivity was located in the cytoplasm of the residual motor neurons. No significant immunoreactivities for other examined products were detected in the familial ALS spinal cords. In the sporadic ALS cases, intense immunoreactivities for pentosidine, CML and HNE-protein adduct were seen in the cytoplasm of the degenerated motor neurons, and OHdG immunoreactivity was located in the cell nuclei of the residual neurons and glial cells. The present results indicate that oxidative reactions are involved in the disease processes of sporadic ALS, while there is no evidence for increased oxidative damage except for CML deposition in the familial ALS spinal cords. Furthermore, it is likely that the accumulation of pyrraline and imidazolone supports a nonoxidative mechanism in SOD1-related motor neuron degeneration.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 37 (1981), S. 809-811 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We describe a highly sensitive assay method for tyrosine hydroxylase (TH) using high-performance liquid chromatography with amperometric determination. This assay method could be applicable to any tissues with low enzyme activity, such as rat cerebellum. We also describe the kinetic properties of TH in rat cerebral cortex.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 31 (1975), S. 660-664 
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Under irradiation by an intense electron beam a V6O13 crystal reacts with the carbon deposited on the surface during microscopic observation. The structural changes during the reaction were directly observed by means of lattice images, in which the array of VO6 octahedra was resolved. At the initial stage cavities smaller than 20 Å in diameter appear preferentially in the thin part of the crystal and some crystallographic shear planes are formed in their wall. The cavities with the heavily distorted surroundings are seen as white regions. Kinks in lattice fringes, indicating the occurrence of stacking faults, are simultaneously found in the matrix. At the advanced stage the VO2 phase and its twin component are produced. The mechanism of the transition of V6O13 to VO2 can be interpreted in terms of the cooperative movement of octahedra.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 32 (1976), S. 558-565 
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The contrast of electron microscope lattice images of a vanadium monosulphide with superstructures was dynamically calculated on the basis of the multislice method. Interactions of 80 waves were analysed. It was shown that the vacancy-rich vanadium sites were imaged as white spots not only at the very thin part but also at the thicker part inside the first equal-thickness contour, which appeared at the thickness of 60 Å. A non-stoichiometric vanadium monosulphide, VS1.155, quenched imperfectly from the preparation temperature at 1217 °C, was examined on the basis of the lattice image observation by a 100 kV high-resolution electron microscope. Orderings in the inter- as well as intralayers could be recognized directly from the arrangement of the white spots. Interpretable lattice images appeared exclusively inside the first equal-thickness contour. A mixture of some different types of images was observed in a crystal fragment; in some band-like regions the 4C-type superstructure was found with almost the same structure as Fe7S8. Each band extended parallel to the (001) plane with thickness of at most 50 Å and the orientation was in a twin relation to that of the adjoining one. The other regions showed less well-defined lattice images, although they gave the broad diffraction peaks ranging from the 4C- to 3C-type reflexions. In order to determine the phase relations at high temperatures the specimen was heated by focusing an electron beam on the portion slightly apart from the area under examination. The technique enabled us to observe only the heating effect. Upon heating, the 4C type first increased in volume, seen by the thickening of some bands. On further heating the 3C type increased in intensity on the diffraction pattern. The structure of the 3C type was estimated to be almost the same as Fe7Se8 except that the vacancy concentration fuctuated among the partially occupied vanadium layers.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 35 (1979), S. 564-569 
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The superstructure of titanium sesquisulfide, TiS1.46, is derived on the basis of 1 MV and 100 kV high-resolution electron microscope images. The crystal has monoclinic symmetry (pseudo-hexagonal) with lattice parameters a = 5-92, b = 10.3, c = 22.8 Å and β = 90°. The space group is Cc. The metal vacancies are confined to every second metal layer and ordered within the layer. They are arranged in a stacking sequence of the 4C-type along the c axis. The sulfur atoms are in the 4H-type stacking sequence along the c axis.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 35 (1979), S. 142-145 
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The crystal structure of bismuth tungstate, Bi2W2O9, has been examined by 1 MV high-resolution electron microscopy. The symmetry is orthorhombic with lattice parameters a = 5.43, b = 5.41 and c = 23.7 Å and space group Pna21. The point group is determined directly from the images in which each cation site is resolved. The structure is similar to that of conventional layered Bi compounds with respect to the Bi2O2 sheets normal to the c axis; however, the layer between the sheets is of a deformed ReO3 type. The strong chemical bonds between the Bi ions and the apex O atoms cause the rotation of the WO6 octahedron about the c axis. W ions are displaced antiparallel in the WO3 layer.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 34 (1978), S. 939-946 
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Images of pale yellow crystals of 4Nb2O5. 9WO3, obtained with a 1 MV high-resolution electron microscope revealed twinned domains of a tetragonal tungsten bronze structure with a superlattice of 3 x 1 subcells. Comparison with computer calculations suggests that the cations filling the pentagonal tunnels include both Nb and W. Crystals darkened due to reduction on longer heating included no domains and were sensitive to electron irradiation; cations were knocked on from the filled to the vacant pentagonal tunnels. This suggests that some oxygens are released from the -M-O-M-O-M- strings in the tunnels on reduction to weaken the chemical bonding. The number of deficient oxygens is known from the weight gain on oxidizing the crystal. Some additional experiments reveal that there is no '6Nb2O5. 1 IWO3' phase. The resolving power of the present microscope is discussed on the basis of the analysis of the chromatic aberration.
    Type of Medium: Electronic Resource
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