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  • 1
    ISSN: 1573-2630
    Keywords: proliferative vitreoretinopathy ; epiretinal membranes ; fibronectin ; vimentin ; macrophages
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Proliferative vitreoretinopathy is characterized by cellular proliferations in the periretinal space resulting in traction retinal detachment. Numerous cellular elements and connective tissue components have been identified by morphologic criteria as well as immunochemical techniques. In this study, we used the recently introduced APAAP (alkaline phosphatase - anti-alkaline phosphatase) immunostaining procedure to identify macrophages, T-lymphocytes, the structural proteins fibronectin, vimentin, and cytokeratin, and a proliferating cell antigen, in eleven human epiretinal membranes obtained during vitreoretinal surgery. Our results confirm that the pathologic processes in PVR are not immunologically mediated, but reveal the features of physiologic wound healing and scar formation. Posttraumatic PVR seems to be characterized by a severe initial inflammatory reaction as evidenced by the presence of numerous macrophages, whereas idiopathic PVR, as a complication of retinal detachment, may be caused by different mechanisms in the early pathogenesis.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Documenta ophthalmologica 69 (1988), S. 341-351 
    ISSN: 1573-2622
    Keywords: fibronectin ; ELISA ; vitreous aspirates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Fibronectin, a high-molecular glycoprotein of the extracellular matrix and plasma, has provoked increasing interest in ophthalmology because of its possibly important role in the pathogenesis of proliferative vitreoretinopathy (PVR). A quantitative determination of fibronectin in vitreous aspirates is necessary for the evaluation of this glycoprotein in PVR. A noncompetitive enzyme-linked immunosorbent assay (ELISA) was developed for the quantification of immunoreactive fibronectin in human plasma samples and vitreous as pirates. Here, procedures to establish an ELISA for the clinical laboratory routine are discussed and possible pitfalls during the assay standardization are described.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-2630
    Keywords: integrins ; vitronectin ; fibronectin ; proliferative diabetic retinopathy ; proliferative vitreoretinopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Several cell types participate in the formation of vitreoretinal traction membranes in proliferative intraocular disorders. The communication between these cells involves hormones, growth factors, and the interaction with extracellular matrix molecules. We have previously demonstrated a partial colocalisation of two potent mediators of cell attachment, fibronectin and vitronectin, in periretinal membranes from patients with proliferative vitreoretinopathy (PVR). We found a similar pattern of vitronectin and fibronectin deposition in proliferative diabetic retinopathy (PDR) (n = 6). Now we show the expression of the corresponding cell surface receptors, integrins, for fibronectin and vitronectin by proliferating cells in 22 periretinal membranes, including traumatic (n = 8) and idiopathic (n = 8) PVR as well as PDR membranes (n = 6). Integrins are membrane receptors for extracellular matrix macromolecules which are involved in such basic biological phenomena as embryogenesis and metastasis. Future studies on the pathogenesis of vitreoretinal proliferation will have to focus on the initiation, maintenance, and regulation of this intercellular communication network involving attachment proteins and integrins.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-2630
    Keywords: vitronectin ; fibronectin ; periretinal membranes ; proliferative intraocular disorders ; immunochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The presence of a scaffold for cellular spreading and proliferation is a precondition for the development of traction membranes in proliferative vitreoretinopathy (PVR). This study shows the presence of the serum spreading factor, vitronectin, in the extracellular matrix of periretinal membranes removed during vitreoretinal surgery. By means of a double label immunofluorescence protocol, a partial colocalisation of vitronectin with fibronectin at the magnification of light microscopy can be detected. Fibronectin is a high-molecular glycoprotein with multiple biological functions including the mediation of cell attachment and migration. Both proteins share a special cell recognition site which could be a target for experimental pharmacological approaches to PVR. Preliminary studies of vitreous aspirates using electrophoresis and Western blotting indicate that vitronectin may play a more important role in post-traumatic PVR as compared to PVR following rhegmatogenous retinal detachment.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-2630
    Keywords: vitronectin ; fibronectin ; periretinal membranes ; proliferative intraocular disorders ; immunochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The presence of a scaffold for cellular spreading and proliferation is a precondition for the development of traction membranes in proliferative vitreoretinopathy (PVR). This study shows the presence of the serum spreading factor, vitronectin, in the extracellular matrix of periretinal membranes removed during vitreoretinal surgery. By means of a double label immunofluorescence protocol, a partial colocalisation of vitronectin with fibronectin at the magnification of light microscopy can be detected. Fibronectin is a high-molecular glycoprotein with multiple biological functions including the mediation of cell attachment and migration. Both proteins share a special cell recognition site which could be a target for experimental pharmacological approaches to PVR. Preliminary studies of vitreous aspirates using electrophoresis and Western blotting indicate that vitronectin may play a more important role in post-traumatic PVR as compared to PVR following rhegmatogenous retinal detachment.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-2630
    Keywords: integrins ; vitronectin ; fibronectin ; proliferative diabetic retinopathy ; proliferative vitreoretinopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Several cell types participate in the formation of vitreoretinal traction membranes in proliferative intraocular disorders. The communication between these cells involves hormones, growth factors, and the interaction with extracellular matrix molecules. We have previously demonstrated a partial colocalisation of two potent mediators of cell attachment, fibronectin and vitronectin, in periretinal membranes from patients with proliferative vitreoretinopathy (PVR). We found a similar pattern of vitronectin and fibronectin deposition in proliferative diabetic retinopathy (PDR) (n = 6). Now we show the expression of the corresponding cell surface receptors, integrins, for fibronectin and vitronectin by proliferating cells in 22 periretinal membranes, including traumatic (n = 8) and idiopathic (n = 8) PVR as well as PDR membranes (n = 6). Integrins are membrane receptors for extracellular matrix macromolecules which are involved in such basic biological phenomena as embryogenesis and metastasis. Future studies on the pathogenesis of vitreoretinal proliferation will have to focus on the initiation, maintenance, and regulation of this intercellular communication network involving attachment proteins and integrins.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 3697-3705 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stable Copper and Silver Derivatives of Phosphorus YlidesTrimethylmethylenephosphorane has been shown to form an ionic 2:1 complex with (CH3)3PCuCl, of the formula [(CH3)3PCH2CuCH 2P(CH3)3]Cl (1). With (CH3)3SiCH2Cu, the molecular species (CH3)3SiCH2CuCH2P(CH3)3 (4) has been isolated, while with CuCl a novel eight-membered heterocycle [(CH3)2P(CH2)2Cu]2 (5)ist formed in a trans-ylidation reaction. The composition and structure of these unusual organocopper compounds have been proved by analytical and spectroscopic methods. The crystal structure of compound 5 has been determined elsewhere. - A silver analogue of 5 (6) is obtained from (CH3)3PAgCl (or AgCl) and (CH3)3PCH2. The detection of 1H-C-107, 109Ag and 31P-C-107,109Ag spin-spin-interactions in the n. m. r. spectra of 6 provided direct evidence for covalent C-Ag bonding in these molecules. The ylides C6H5(CH3)2PCH2 and CH3(C6H5)2PCH2 are forming similar Cu- and Ag-heterocycles (7a, b, 8a, b), but these compounds are of a markedly reduced thermal and chemical stability if compared with 5 and 6.
    Notes: Trimethylmethylenphosphoran bildet mit (CH3)3PCuCl einen ionogenen 2:1-Komplex der Formel [(CH3)3PCH2CuCH 2P(CH3)3]Cl (1), mit (CH3)3SiCH2Cu die Molekülverbindung (CH3)3SiCH2CuCH 2P(CH3)3 (4) und mit CuCl unter Umylidierung den neuartigen achtgliedrigen Heterocyclus [(CH3)2P(CH2)2Cu]2 (5). Die Zusammensetzung und Konstitution dieser kupferorganischen Verbindungen mit stabilisierendem Oniumzentrum wurden mit analytischen und spektroskopischen Methoden sichergestellt. Für 5 liegt von anderer Seite eine Röntgenstrukturanalyse vor. - Aus (CH3)3PCH2 und (CH3)3PAgCl entsteht nur die zu 5 analoge Silberverbindung 6, in deren NMR-Spektren die über echte Ag-C-σ-Bindungen vermittelten Spin-Spin- Wechselwirkungen 1H-C-107,109Ag und 31P-C-107,109Ag beobachtet werden können. Auch die Ylide C6H5(CH3)2PCH2 und CH3(C6H5)2PCH2 bilden derartige Cu- und Ag- Heterocyclen, die jedoch im Gegensatz zu 5 und 6 nur geringe thermische und chemische Beständigkeit aufzuweisen haben (7a, b, 8a, b).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 2696-2701 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Properties of Some Silacyclic Phosphorus YlidesA disilacyclobutane derivative with an exocyclic function (1) has been synthesized by the reaction of double-lithiated (CH3)3P = CH2 with CH2[Si(CH3)2Cl]2 and characterized by 1H, 13C, and 31P NMR spectroscopy. In this reaction varying amounts of an isomer 2 are also formed, in which the functional group is an integral part of the six-membered ring. Transsilylation of the same halosilane with (CH3)3P = C[Si(CH3)3]2 is accompanied by transylidation, yielding the octalene-analogous bicyclic ylide 4, the P = C moiety being shared by both rings. In corresponding reactions with the components (CH3)2Si[CH2Si(CH3)Cl2]2 and [CH2Si(CH3)2Cl]2 the strain-free ylides 5 and 6 are obtained.
    Notes: Durch die Umsetzung von doppelt lithiiertem (CH3)3 P = CH2 mit CH2[Si(CH3)2Cl]2 wurde ein Disilacyclobutanderivat (1) mit exocyclischer Ylidfunktion synthetisiert und 1H-, 13C- und 31P-NMR-spektroskopisch charakterisiert. Bei der gleichen Reaktion entstehen wechselnde Mengen eines Isomeren 2, in dem die funktionelle Gruppe in das Sechsringsystem integriert ist. Die Umsilylierung des gleichen Halogensilans mit (CH3)3P = C[Si(CH3)3]2 liefert unter nachfolgender Umylidierung den octalin-analogen Bicyclus 4, in dem die P = C-Einheit beiden Ringen gemeinsam ist. Mit den Komponenten (CH3)2Si[CH2Si(CH3)2Cl]2 und [CH2Si(CH3)Cl2]2 entstehen bei entsprechenden Ansätzen die spannungsfreien silacyclischen Ylide 5 und 6.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 98 (1965), S. 1949-1955 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Borsäure bzw. Bortrioxid bildet mit Carbonsäureanhydriden bzw. Carbonsäuren gemischte Anhydride, die mit β-Diketonen über deren Enolform zu Borkomplexen reagieren. Diese sind eine wichtige Zwischenstufe bei der durch Borsäure katalysierten Synthese von α- und γ-Pyronen aus Fettsäuren oder Fettsäureanhydriden. Der Mechanismus dieser Reaktion wird diskutiert.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 98 (1965), S. 114-119 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quercetin läßt sich mit Allylbromid zum 6-C-Allyl-quercetin-3.7.3′.4′-tetraallyläther (II) umsetzen, Quercetin-pentaacetat zum 7-O-Allyl-quercetin-3.5.3′.4′-tetraacetat (IV), das zum 7.4′-Di-O-allyl-quercetin-triacetat (VII) weiter allyliert werden kann. 3.4′-Dihydroxy-flavon wurde zum 3.4′-Diallyloxy-flavon (X) allyliert. Durch Claisen-Umlagerung wurde aus 7-O-Allyl-quercetin-3.5.3′.4′-tetramethyläther der 8-C-Allyl-quercetin-3.5.3′.4′-tetramethyläther gewonnen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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