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  • Analytical Chemistry and Spectroscopy  (12)
  • Altersabhängige Makuladegeneration  (3)
  • Organic Chemistry  (3)
  • 1
    ISSN: 1433-0423
    Keywords: Key words Scanning laser ophthalmoscopy ; Fluorescein angiography ; Indocyanine green angiography ; Choroidal neovascularization ; Age-related macular degeneration ; Schlüsselwörter Scanning-Laser-Ophthalmoskopie ; Fluoresceinangiographie ; Indozyaningrünangiographie ; Choroidale Neovaskularisation ; Altersabhängige Makuladegeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Fragestellung: Wir berichten über klinische Erfahrungen mit einem neuen konfokalen Scanning-Laser-Ophthalmoskop zur simultanen Fluorescein- und Indozyaningrün (ICG)-Angiographie. Material und Methode: Die digitalen Aufnahmen erfolgten nach gleichzeitiger Injektion von Fluorescein und ICG mit dem Heidelberg-Retina-Angiograph (HRA). Als Erregerlicht wurden ein Argon- (488 nm) und ein Diodenlaser (795 nm) angewendet. Die Emission wurde zwischen 500 und 650 nm bzw. über 810 nm erfaßt. Ergebnisse: Insgesamt wurden 295 simultane Angiogramme bei verschiedenen Fundusveränderungen einschließlich exsudativer altersabhängiger Makuladegeneration durchgeführt. Die Aufnahmen zeichneten sich durch einen hohen Kontrastreichtum aus. Die Mischung und gleichzeitige Injektion beider Farbstoffe war nicht mit zusätzlichen Nebenwirkungen assoziiert. Schlußfolgerung: Mittels des HRA ist eine simultane Fluorescein- und ICG-Angiographie möglich. Im Vergleich zu konsekutiven Angiographien mit beiden Farbstoffen besitzt sie den Vorteil des geringeren Zeitaufwands, einer nur 1maligen Farbstoffinjektion sowie eine einfachere Interpretation aufgrund der simultanen Darstellung der jeweils farbstofftypischen Befunde.
    Notes: Background: We report on our clinical experience with a recently developed confocal scanning laser ophthalmoscope for simultaneous fluorescein and indocyanine-green (ICG) angiography. Materials and methods: Following injection of fluorescein and ICG mixed in one syringe simultaneous confocal scanning laser fluorescein and ICG angiography were carried out using the Heidelberg Retina Angiograph (HRA). An argon laser (488 nm) and a diode laser beam (795 nm) from an external source were delivered via single-mode fibers. Emission was recorded between 500 and 650 nm and above 810 nm, respectively. Digital images were displayed simultaneously on a monitor during angiography. Results: A total of 295 simultaneous angiograms in 268 patients with various retinal and choroidal diseases, including exudative age-related macular degeneration with occult and classic choroidal neovascularization, were obtained. High-contrast images during all phases of the angiography were obtained. Besides mild side effects in similar frequency known from individual injections, no additional toxic or allergic reactions from simultaneous injections of the two dyes were observed. Conclusions: Confocal laser scanning angiography allows for simultaneous fluorescein and ICG angiography. Compared with consecutive investigations using both dyes, simultaneous angiography requires only one injection, and offers identical digital frames. Simultaneous injection is not associated with additional side effects.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1433-0423
    Keywords: Schlüsselwörter Autofluoreszenz ; Lipofuszin ; Retinales Pigmentepithel ; Altersabhängige Makuladegeneration ; Makuladystrophie ; Key words Autofluorescence ; Lipofuscin ; Retinal pigment epithelium ; Age-related macular degeneration ; Macular dystrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Background: We investigated fundus autofluorescence in vivo using a novel scanning laser ophthalmoscope. Materials and methods: A total of 550 patients with various retinal diseases were examined and compared with normal eyes. Autofluorescence was detected after excitation with an argon blue laser (488 nm), and emission was recorded with a short wavelength cut off above 500 nm. Results: Reduced autofluorescence was observed in the foveal and parafoveal region due to retinal xanthophyll, along the retinal vessels, at the optic nerve head and in areas with atrophy of the retinal pigment epithelium (RPE). Autofluorescence intensity was increased either focally or diffusely in certain degenerative (AMD) or genetically determined retinal diseases (e. g., Stargardt's disease, Best's disease). Conclusions: These findings are in accordance with the view that in vivo fundus autofluorescence originates at the level of the RPE and suggest that it is derived from lipofuscin.
    Notes: Hintergrund: Wir untersuchten die Erfassungsmöglichkeiten der Fundusautofluoreszenz und deren topographische Verteilung mit einem neuen konfokalen Scanning-Laser-Ophthalmoskop. Material und Methode: 550 Augen normaler Probanden und Patienten mit verschiedenen retinalen Erkrankungen wurden mit dem Heidelberg-Retina-Angiograph (HRA) untersucht. Die Fundusautofluoreszenz wurde nach Exzitation mit einem Argonlaser (488 nm) und Detektion des emittierten Lichts oberhalb von 500 nm erfaßt. Ergebnisse: Im Bereich makulären Xanthophylls, retinaler Gefäße, der Papille und Atrophie des retinalen Pigmentepithels (RPE) war die Autofluoreszenz vermindert. Genetisch determinierte und degenerative retinale Veränderungen gingen z. T. mit erhöhter, irregulärer Autofluoreszenzintensität einher (u. a. Morbus Best, Morbus Stargardt, AMD). Schlußfolgerung: Der Heidelberg-Retina-Angiograph ermöglicht die topographische Erfassung der Fundusautofluoreszenz in vivo. Die Befunde unterstützen die Annahme, daß die Autofluoreszenz durch Akkumulation von Lipofuszingranula im RPE induziert wird.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1433-0423
    Keywords: Schlüsselwörter Indozyaningrünangiographie ; Heidelberg-Retina-Angiograph ; Choroidale Neovaskularisation ; Altersabhängige Makuladegeneration ; Key words Indocyanine green angiography ; Heidelberg Retina Angiograph ; Choroidal neovascularization ; Age-related macular degeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: ``Classic'' choroidal neovascularization (CNV) has a relatively uniform appearance in fluorescein angiography. In contrast, indocyanine green (ICG) angiography shows variable features of well-defined CNV. We examined 31 classic CNV patients secondary to age-related macular degeneration using a confocal laser scanning ophthalmoscope (Heidelberg Retina Angiograph) in order to determine ICG characteristics of classic CNV. Vascular patterns (97%), a hypofluorescent rim (84%), a hyperfluorescent margin (42%), late ICG leakage (32%) and ``feeder vessels'' were identified in variable frequency. Some of the ICG characteristics may correlate with histological features of the membrane and reflect proliferative activity. Extrafoveal ``feeder vessels'' may be amenable to laser photocoagulation in the presence of subfoveal CNV.
    Notes: Klassische choroidale Neovaskularisationen (CNV) stellen sich in der Fluoresceinangiographie relativ uniform dar, während sie in der Indozyaningrün (ICG)-Angiographie unterschiedliche Aspekte zeigen. Zur weiteren Bestimmung ICG-angiographischer Charakteristika wurden 31 Patienten mit klassischer CNV bei altersabhängiger Makuladegeneration mittels eines konfokalen Scanning-Laser-Ophthalmoskops (Heidelberg-Retina-Angiograph) untersucht. In unterschiedlicher Häufigkeit wurden abgrenzbare Gefäßmuster (97%), ein hypofluoreszenter Randsaum (84%), ein hyperfluoreszenter Membranrand (42%), ICG-Leckagen (32%) und umschriebene Feeder vessels (29%) erkannt. Die ICG-angiographischen Besonderheiten einzelner CNV gehen auf histologische Merkmale der Membran zurück und lassen ggf. Rückschlüsse auf das Ausmaß der proliferativen Aktivität zu. Extrafoveal darstellbare sog. Feeder vessels könnten insbesondere bei subfovealer CNV einer Laserkoagulation zugänglich sein.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The solid-state CP/MAS 13C-NMR spectra (cross-polarization/magic-angle spinning 13C-NMR) of eight lower cyclic and one linear oligomers and several polymers of (R)-3-hydroxybutanoic acid (3-HB) are reported. The polymeric samples of different origin and molecular weight give remarkably similar and well resolved spectra, indicating considerable similarity in the conformations of the molecules and homegeneity in the solid-state environment. The crystalline cyclic oligomers 1-8 containing 3-9 units of 3-HB give very well resolved spectra. The number of nonequivalent positions in the solid state can be identified and is in accord with structures from X-ray diffraction where these were determined. The spectra of the oligolides become increasingly similar to those of the polymer as the ring size increases. This spectral evidence supports the view of a homogeneous and well defined conformation for the polymeric material (as proposed previously, based on other experiments).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 716 (1968), S. 29-36 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stannyl-alkine reagieren mit Phenylisocyanat überraschenderweise zu 5-Alkylidenhydantoinen 3, mit Diphenyl-tetrazin in einer Diels-Alder-Reaktion zu Pyridazinen 6, mit Jod zu Jod-alkinen; Carbonsäure-chloride führen zu Alkinyl-ketonen, polarisierte Carbonyl-Verbindungen analog einer Grignard-Reaktion zu substituierten Propargylalkoholen.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 716 (1968), S. 19-28 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stannylierte Alkine RnSn(C = C - R′)4-n mit n = 0, 2, 3 (Tabb. 2, 3) werden einfach und schonend dargestellt durch azeotropen Wasser-Entzug aus dem freien Alkin und Dialkyl(bzw. -aryl)-zinnoxid oder Trialkyl(bzw. -aryl)-zinnoxid. Der Rest R′ kann funktionelle Gruppen tragen, z.B. OCH3, CONH2, CO2CH3 und CN. Das Verfahren ist auch auf Pb- und Hg-Alkin-Verbindungen anwendbar. Der Mechanismus von Knüpfung und Hydrolyse der C≡C-Sn-Gruppe wird untersucht. Sowohl aus vergleichenden IR-Studien wie aus Valence-Bond-Berechnungen (VB + CI-Methode) folgt, daß am Bindungssystem eine Struktur C≡C-Sn beteiligt ist.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 300 MHz 1H NMR spectrum of 4-vinylbutyrolactone has been recorded and analysed. The results showed that the compound is a mixture of two rapidly interconverting envelope forms in which (C-3) is the flap atom. The vinyl group favours the pseudo-equatorial orientation by 1·9 ± 0.3 kJ mol-1, as shown by the dependence of the vicinal coupling constants on temperature.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 14 (1980), S. 324-326 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nitrogen inversion barriers of nine 3,6-dihydro-1,2-oxazines are discussed. Polar solvents were found to increase the nitrogen inversion barriers which, in turn, decrease with increasing size of the N-substituent.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 33 (1995), S. 600-602 
    ISSN: 0749-1581
    Keywords: NMR ; 13C NMR ; Tetrahydro-1, 3-oxazines ; ring chain tautomerism, solid-state NMR ; kinetics ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Condensation of cis-2-aminomethylcyclohexanol with p-nitrobenzaldehyde under mild conditions initially gives the imine as the kinetically controlled product. The imine undergoes a solid-state rearrangement to the bicyclic tetrahydro-1, 3-oxazine. The kinetics of the rearrangement were followed by solid-state CP/MAS 13C NMR spectroscopy over the temperature range 283-297 K and the reaction was shown to have an activation energy of 85.0 ± 14.7 kJ mol-1. The probable reaction mechanism is discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 33 (1995), S. 841-843 
    ISSN: 0749-1581
    Keywords: NMR ; solid-state NMR ; CP/MAS NMR ; dynamic NMR ; phenyl rotation ; trimethylammonium rotation ; methyl rotation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 13C CP/MAS NMR spectra of trimethyl(3-phenylpropyl)ammonium bromide show evidence of three independent rotational processes in the solid: methyl rotation, trimethylammonium rotation and phenyl rotation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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