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  • Aromaticity  (1)
  • Autoantibody  (1)
  • 1995-1999  (2)
  • 1980-1984
  • 1955-1959
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 1434-1948
    Keywords: Phosphorus heterocycles ; Aromaticity ; Phosphenium cations ; Ab initio calculations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The aromatic stabilization of cyclic phosphenium cations (general type C2N2P+) was studied by experimental methods (synthesis, multinuclear NMR, single crystal X-ray crystallography) and quantum chemical calculations (ab initio methods). The structures of the 1,3,2-diazaphosphole derivatives [(tBuN-CH=CH-NtBu)P+]Cl- (1), (tBuN-CH2-CH2-NtBu)P-Cl (2), [(tBuN-CH=CH-NtBu)P]+PF6- (3) and [(tBuN-CH2-CH2-NtBu)]P+PF6- (4) were examined by single crystal X-ray diffraction. The chloro phosphane [(tBuN-CH=CH-NtBu)P]+Cl- (1) has an ionic P-Cl bond and contains an aromatically stabilized phosphenium cation [shortest distance P···Cl = 275.9(2) pm], while the CC-saturated compound (tBuN-CH2-CH2-NtBu)P-Cl (2) is covalent. The two chloro-phosphanes 1 and 2 differ sharply in their volatility and solubility in organic solvents. Compound 2 is soluble in hydrocarbons and sublimes readily at 90 °C/0.1 Torr but 1 is insoluble in hexanes and not volatile below 180 °C/0.1 Torr. The degree of aromatic stabilization in the phosphenium cation 1 was investigated by ab initio methods. For the model cations [RN-CH2-CH2-NR]P+ and [(RN-CH=CH-NR)P]+, thermochemical stabilization energies of 25.8 kcal · mol-1 (R = H) and 28.1 kcal · mol-1 (R = Me) were obtained from isodesmic hydrogenation reactions at the RHF/MP2/6-31G*//RHF/6-31G* level.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1433-0423
    Keywords: Schlüsselwörter Episkleritis ; Skleritis ; Systemerkrankung ; Autoantikörper ; Key words Episcleritis ; Scleritis ; Systemic disease ; Autoantibody
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Background: Episcleritis and scleritis can be caused by various systemic disorders, which can be triggered by infectious diseases. We studied the autoantibody pattern against various organ-specific and non-organ-specific antigens in episcleritis and scleritis patients. Material and methods: Sera from 46 patients (episcleritis n = 28, scleritis n = 18) were studied for antibodies against nuclei, smooth muscle cells, mitochondria, endothelial cells, sarcolemma, liver cells, heart muscle fibrils, parietal cells and thyroid cells by immunofluorescence testing. Titers of antibodies against thyroglobulin, laminin, keratin and microsomes were evaluated by ELISA. Results: In patients with episcleritis the pattern of autoantibodies found was different from that in scleritis patients. Thus, in epi-scleritis the levels of antibodies against sarcolemma (32%), parietal cells (25%), laminin (38%), keratin (58%) and microsomes (28%) were elevated, while scleritis patients, besides keratin antibodies (50%), demonstrated anti-nuclear antibodies (ANA) in 28% of cases. These differences were not significant. Approximately 5% of normal control patients show these antibodies. Conclusions: Previous studies have shown that episcleritis rarely develops into scleritis. Our results suggest that this may be due to different underlying diseases. While 28% of scleritis patients had ANA, which may suggest an autoimmune disposition related to collagenosis, episcleritis patients had a different autoantibody pattern such as has been found in various infectious diseases and diseases for which triggering by infectious organisms seems possible, such as anterior uveitis, ankylosing spondylitis and Behçet disease. Investigations in larger groups of patients are needed to check the statistical significance of these differences.
    Notes: Fragestellung: Episkleritis und Skleritis können zahlreiche Systemerkrankungen zugrundeliegen, die teilweise durch Infektionen ausgelöst sein können. Wir haben bei diesen Patienten das Autoantikörpermuster gegen zahlreiche organspezifische und organunspezifische Antigene untersucht. Material und Methodik: Seren von 46 Patienten (Episkleritis n = 28, Skleritis n = 18) wurden mittels Immunfluoreszenztest untersucht hinsichtlich Antikörpern gegen Kerne, glatte Muskelzellen, Mitochondrien, Endothelzellen, Sarkolemm, Leberzellen, Herzmuskelfibrillen, Parietalzellen und Schilddrüsenzellen. Mittels ELISA wurden die Titer gegen Thyreoglobulin, Laminin, Keratin und Mikrosomen bestimmt. Ergebnisse: Es ergab sich bei Episkleritispatienten ein anderes Autoantikörperprofil als bei Skleritispatienten. So ließen sich bei Episkleritis Antikörper gegen Sarkolemm (32%), Parietalzellen (25%), Laminin (38%), Keratin (58%) und Mikrosomen (28%) nachweisen, während bei Skleritispatienten neben ebenfalls erhöhten Keratintitern (50%) antinukleäre Antikörper (28%) gefunden wurden. Allerdings sind die Unterschiede nicht signifikant. Gesunde Kontrollpersonen weisen diese Antikörper zu ca. 5% auf. Schlußfolgerung: Frühere Studien haben gezeigt, daß eine Episkleritis nur selten in eine Skleritis übergeht. Unsere Ergebnisse lassen vermuten, daß dies u. a. an der zugrundeliegenden Erkrankung liegt. Während sich bei Skleritispatienten zu 28% antinukleäre Antikörper nachweisen ließen, die auf eine autoimmune Disposition für Erkrankungen aus dem Kreis der Kollagenosen hindeuten, zeigten die Episkleritispatienten ein Autoantikörpermuster, wie es bei zahlreichen Systemerkrankungen gefunden wurde, bei denen eine infektiöse Genese diskutiert wird, wie anteriore Uveitis, ankylosierende Spondylitis und Morbus Behçet. Größere Patientengruppen sind notwendig, um eine klarere statistische Aussage zu treffen.
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