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  • 1
    Electronic Resource
    Electronic Resource
    4,4′-Distyrylazobenzol als Chromophor (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 889-892 
    Details
    ISSN: 0009-2940
    Keywords: Wittig reaction ; Siegrist reaction ; Azo compounds ; Photochemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 4,4′-Distyrylazobenzene as Chromophore4,4′-Distyrylazobenzenes are prepared from 4,4′-dimethylazobenzene. Whereas the Siegrist method furnishes stereoselectively the (E,E,E) configuration, a Wittig olefination leads to a mixture of (Z,E,Z), (Z,E,E) and (E,E,E) isomers which can be easily separated. Irradiation of the intense absorption at λ ≈ 400 nm causes a selective (E) → (Z) isomerization of the N = N bond of all three isomers. The reverse reaction takes part in the photochemical equilibration, moreover, it is a thermal process with a relatively low activation barrier.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250420
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  • 2
    Electronic Resource
    Electronic Resource
    Development of the high endothelial venule in rat lymph node autografts (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 238 (1994), S. 473-479 
    Details
    ISSN: 0003-276X
    Keywords: High endothelial venules ; Autograph ; Lymph node ; RAF ; Regeneration ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Vascular reconstruction during rat lymph node regeneration was investigated in autotransplanted mesenteric lymph node fragments, which had been implanted in the renal parenchyma. In addition to light microscopy, vascular casting and transmission electron microscopy were used. From day 3 onwards capillaries grew into the autografts together with lymphatic vessels. The capillaries showed obvious signs of proliferation by day 5. The surviving interstitial cell at the outer border of the transplant produced extracellular substance. High endothelial venules (HEV) differentiated from capillaries from about day 7. A first sign of their development was a vessel with a narrow, branching luminal space and with endothelial cells containing rich cytoplasm and small Golgi complexes. As the Golgi complexes grew and the cisternae and vesicles increased, the lumen dilated, the cell coat on the luminal surface became prominent, and, finally, lymphocytes emigrated through these venules from around day 10. The typical lymph node structure was complete by day 28. These results suggest that the interaction among the remaining interstitial cells, invading capilaries, and lymphatic penetration results in differentiation and maturation of HEV in lymph node regeneration. The development of Golgi complexes is strongly associated with lymphocyte emigration from the blood. © 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092380406
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Embryological development of the arterial system of the forelimb in Tupaia (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 240 (1994), S. 416-422 
    Details
    ISSN: 0003-276X
    Keywords: Tupaia ; Forelimb ; Artery ; Comparative embryology ; Three-dimensional reconstruction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: The arterial system of the upper extremities in man shows drastic developmental changes and many individual variations related to interspecific variations in primates. The ontogenetic development in Tupaia was examined from the viewpoint of comparative embryology.Methods: Histological specimens of 39 embryos were observed and reconstructed in three dimensions using a computer program. Four adult animals were dissected and examined with angiography to ascertain the end stage of development.Results: At the proximal end of the upper arm the deep brachial artery appears first as a concomitant vessel with the radial nerve. It becomes reduced in size and is succeeded by the posterior circumflex humeral artery, which is accompanied initially by the axillary nerve and finally by the radial nerve. The main arterial passageway to the fingers consists of the brachial and interosseous arteries during early development. The superficial brachial artery and median artery are formed later, and their connection becomes the main route of blood supply for the finger arteries up to the adult stage. The ulnar artery is formed at the end of arterial development to form the ulnar end of the superficial palmar arch. The superficial antebrachial arteries are also recognized.Conclusions: All the arterial elements of the forelimb in Tupaia are observed in a variety of primates, including man, and the characteristics of Tupaia are thought to represent the primitive conditions of the common ancestor of tree shrews and primates. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092400314
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  • 4
    Electronic Resource
    Electronic Resource
    Three-dimensional detection of the expression of intercellular adhesion molecule-1 (ICAM-1) in the high endothelial venule (HEV) of the rat lymph node (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 25 (1993), S. 264-265 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070250308
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of cytokines on synthesis and function of the hepatic asialoglycoprotein receptor (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 158 (1994), S. 527-534 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In this study we have investigated whether cytokines, critical mediators of the immune response, might have a direct effect on the expression and/or function of the human hepatic asialoglycoprotein receptor (ASGPR). Binding and uptake of asialoglycoproteins by the human hepatoma cell line, HepG2, and by freshly isolated rat hepatocytes were inhibited by 50% after 3-6 hours and completely abolished following a 24 hour exposure to tumor necrosis factor (TNF) α, interferon (INF) α or γ, or interleukin-2 (IL-2). The loss of ASGPR binding activity mediated by IL-2 was reversible up to 4 hours of exposure and accompanied by the selective phosphorylatior, of the cell-surface receptor. Steady-state levels of total cellular ASGPR protein remained unchanged over the first 6 hours of IL-2 incubation but declined in a dose dependent manner thereafter. This down regulation of ASGPR expression was due to reduced synthesis as a result of reduced receptor transcript levels. No loss was detected, however, of cell surface-associated receptor protein even after 24 hours of IL-2 incubation, suggesting that cytokine induced phosphorvlation constitutes a mechanism to regulate receptor activity. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041580319
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  • 6
    Electronic Resource
    Electronic Resource
    High resolution biological scanning electron microscopy: A comparative study of low temperature metal coating techniques (1991)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 18 (1991), S. 440-449 
    Details
    ISSN: 0741-0581
    Keywords: High resolution SEM ; Cryomethods ; Double-axis rotary shadowing ; Unidirectional shadowing ; Planar-magnetron sputtering ; Chromium ; Platinum/carbon ; T4 phages ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Structural information on the surface of biological specimens can be resolved within molecular dimensions by “in-lens” field emission scanning electron microscopes when cryo-methods are used to adequately preserve the native state of the specimen. The visual definition of molecular surface structures depends largely on the metal coating. The thickness of the coating, as well as the temperature at which it is deposited, are among the most important parameters affecting visual definition. These were evaluated on T4 polyheads and T4D phages using chromium double-axis rotary shadowing (DARS). Micrographs of optimally DARS coated T4 polyheads and T4D phages were compared with chromium planar-magnetron sputtering (PMS) and unidirectional shadowing with platinum/carbon. Metal deposition was carried out at low temperatures during all three procedures.Optimal visual definition of structural details on the surface of DARS coated T4 polyheads and T4D phages (capsomeres of T4 polyheads and their subunits with diameters of 8 and 3 nm; T4D phage tail fibres with a thickness of 3 nm) is achieved at a thickness of the chromium film greater than the minimum required for metal film coalescence. Chromium DARS coating at room temperature resulted in poor structural definition, whereas DARS at specimen temperatures of -85°C and -150°C, with the chromium thickness optimized for each temperature, yielded good visual detail of polyhead substructures. The visual definition was slightly reduced when DARS coating was carried out at a specimen temperature of -250°C. Adequate structural visibility of T4D phage and T4 polyhead surface structures was achieved with the three coating techniques tested. Smaller filamentous structures, however (e.g., phage tail fibres), were more clearly identified after chromium DARS coating or unidirectional platinum/carbon shadowing than after optimized PMS with chromium. Each method has its own merits.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1060180414
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