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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Archives of dermatological research 287 (1994), S. 85-90 
    ISSN: 1432-069X
    Schlagwort(e): Proopiomelanocortin ; Immune neuroendocrine network ; Cytokines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Proopiomelanocortin (POMC) is known to be synthesized in the pituitary gland and is subsequently cleaved by specific prohormone convertases into biologically active peptide hormones such as melanocyte stimulating hormones (MSH), adrenocorticotropin (ACTH) and endorphins (EP). Guanine nucleotide-binding protein (G-protein)-coupled receptors, which have only recently been discovered, are involved in the transmission of their message. There is also evidence indicating that POMC is not only produced by pituitary cells but is an ubiquitous molecule, that is cleaved cell- and tissue-specific. It has also been shown that the epidermis keratinocytes as well as melanocytes express POMC upon stimulation and release αMSH and ACTH. In addition to their function as hormones, POMC peptides have been shown to exert a variety of immunoregulatory effects by modulating the function of immunocompetent cells as well as cytokines. These findings provide further evidence for the immunoneuroendocrine network playing a crucial role during the pathogenesis of immune and inflammatory skin disease.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 32 (1983), S. 211-215 
    ISSN: 1432-0630
    Schlagwort(e): 72.20. Jv ; 72.40. + W
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract The effect of a preliminary illumination on the amount of polarization generated in the subsequently dark-polarized Kapton-H samples has been investigated by using the uv and visible radiations as an excitation source. The magnitude of this effect is governed by the two excitation parameters, viz. duration of the illumination (t ex) and the time interval (Δt) between the end of illumination and the outset of the polarizing electric field. A rise in the operating temperature makes the appearance of the phenomenon more pronounced. The uv radiation has been found more efficient than the visible one for producing the excitation effect.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 35 (1984), S. 267-270 
    ISSN: 1432-0630
    Schlagwort(e): 72.20-Jv ; 72.40.+W
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract The photoinduced polarization in Kapton-H thin film has been studied by analysing the isothermal dark decay characteristics of photo- and dark-polarized specimens for different values of the polarizing parameters. The total polarization induced has been found to increase continuously with polarizing temperature but with polarizing field, it approaches a saturation. The behaviour of dark decay currents for photo and dark polarized identical samples changes with operating temperature. The phenomenon is explained in terms of the shift of electrons and hole demarcation levels under variation of temperature and illumination intensity.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 14
    ISSN: 1573-4838
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Technik allgemein
    Notizen: Abstract Synthetic polymer meshes are widely applied in the modern surgical approach for repairing abdominal wall defects. The implanted material is often observed leading to post-operative complications such as deficient abdominal wall mobility and adhesion formation with the abdominal cavity and/or abdominal organs. However, the functioning of the implant is primarily affected by the wound healing process guided by inflammatory events occurring at the tissue–material interface. This could presumably be influenced by the physicochemical properties of the polymer. With regard to it, the cellular and molecular processes involved in the successful restoration of the abdominal wall function are poorly understood. The present in vivo study, therefore, exemplary investigated in a rat model, the commercially available polymer-meshes Prolene® (polypropylene, PP), Mersilene® (polyester, PE) and Vicryl® (polyglactin 910), as well as new mesh variants consisting either of PP (EB) or a combination of PP and polyglactin 910 (A plus or Vypro®). The implanted material was evaluated by light and electron microscopy, immunohistochemistry as well as morphometry over an implantation period of 90 days. The data show that polymers induce heat shock protein (HSP)70, and its expression at the interface correlates inversely with the activity of the inflammatory reaction in vivo. Further, an ascent in HSP70 expression parallels the increasing implantation period and evolving foreign-body granulomas. Accordingly, a major role for HSP70 in modulating the local acceptance of polymers and as an additional marker for in vivo testing of polymers is suggestive. ©©2000 Kluwer Academic Publishers
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 15
    ISSN: 1573-4838
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Technik allgemein
    Notizen: Abstract For the in vitro study of cell–biomaterial surface interactions, the choice of cell type is crucial. In vivo data indicate that during the healing of the implant in the tissues, the pivotal cell types are the macrophages. These cells, upon interaction with any foreign material, might initiate a spectrum of responses, which could lead to acute and chronic inflammatory changes affecting the biocompatibility of the implant. Whether the mechanisms governing the type of evolving inflammatory reaction could be attributed to the macrophages functional differentiation mirrored by monocyte subsets during the polymer interaction, is poorly described. This in vitro study, therefore, attempted to investigate whether different biomaterials influence monocyte cellular activity, determined by the myeloperoxidase level and mitochondrial XTT cleavage, and phenotype dynamics characterized by the presence of CD14, RM 3/1 and 27E10 antigens. It is shown that different polymers exert differential potential to influence monocytes, both in their cellular activity and their phenotypic pattern. Thus, these findings demonstrating material-induced monocyte activation and monocyte phenotype modulation, are suggestive of the monocyte role as reporter cells in evaluating the biocompatibility of a synthetic medical device.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Tropical animal health and production 12 (1980), S. 95-96 
    ISSN: 1573-7438
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Tropical animal health and production 13 (1981), S. 222-226 
    ISSN: 1573-7438
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Des investigations sérologiques par la méthode de l'agglutination indirecte pour rechercher des anticorps toxoplasmiques ont été faites sur un troupeau de chèvres laitières. Des anticorps ont été mis en évidence chez 34 p.100 des 371 animaux apparemment sains à des titres allant de 1:4 à 1:1024. Des titres élevés d'anticorps atteignant 1:256 ont été relevés chez 18 (soit 4,9 p.100) des animaux comprenant 13 chèvres, ce qui fait penser à une infection récente. L'existence de nombre d'avortements non-brucelliques associés avec des titres sérologiques élevés et l'isolement du parasite des tittus cérébraux d'un foetus avorté suggerent que les Toxoplasmes en ont probablement été le facteur étiologique. Des sérums ayant des taux significativement élevés d'anticorps agglutinants (1:128) ont également été reconnus comme positifs par le test d'agglutination en EAT. Les aspects épidémiologiques et le danger potentiel pour l'homme de ces cas subcliniques de toxoplasmose chez les chèvres laitières sont discutés.
    Kurzfassung: Resumen Se realizaron investigaciones serológicas de toxoplasmosis mediante la prueba indirecta de hemaglutinación en un rebaño de cabras lecheras. Se encontraron títulos de 1:4 a 1:1024 en 34% de 371 animales aparentemente sanos. Títulos de 1:256 sugestivos de infecciones recientes, se encontraron en 18 (4.9%) animales, incluyendo 13 hembras paridas. La ocurrencia de un significativo número de abortos no asociados con brucela, títulos serológicos altos de toxoplasmosis y el aislamiento del parásito del cerebro de fetos abortados, sugiere que eltoxoplasma es el factor etiológico más importante. Se discuten aspectos epidemiológicos de importantcia para la salud pública, relacionados con el potencial de la toxoplasmosis (subclínica) en cabras lecheras.
    Notizen: Summary Serological investigation by the indirect haemagglutination test forToxoplasma antibodies was carried out in a flock of dairy goats. Antibody titres ranging from 1:4 to 1:1,024 were found in 34% of 371 apparently healthy animals. High antibody titres of 1:256 suggestive of recent infection were noted in 18 (4.9%) animals including 13 nannies. The occurrence of a number of non-brucella abortions associated with high serological titres and the isolation of the parasite from the brain tissues of an aborted foetus suggestedToxoplasma as a probable aetiologic factor. Sera having significant levels of haemagglutinating antibodies (≥1:128) were also found positive to the card agglutination test. Epidemiological aspects and the public health potential of subclinical toxoplasmosis in dairy goats are discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Flow, turbulence and combustion 45 (1988), S. 233-250 
    ISSN: 1573-1987
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract Turbulence in decaying swirl flow through a pipe is studied experimentally by using a single rotating inclined hot-wire probe and the results are presented in the form of profiles of the three mean velocities and the six components of the stress tensor. The results indicate that all the nine components are very weakly influenced by the Reynolds number, but strongly depend on the initial swirl. The swirling stream develops two regions of flow which are characterized by the variation of the tangential velocity and the Reynolds stresses. It was also found that the turbulence intensities are higher at the core and with the decay of the swirl their magnitudes reduce markedly at the core while they change slightly near the wall.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Langenbeck's archives of surgery 382 (1997), S. 87-94 
    ISSN: 1435-2451
    Schlagwort(e): Hernia repair ; Mesh ; Complications ; Biocompatibility ; Rat model ; Hernienchirurgie ; Netz ; Komplikationen ; Biokompatibilität ; Ratte
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die moderne Hernienchirurgie bedient sich zunehmend Kunstnetzkonstruktionen zur Bauchwandrekonstruktion. Trotz der unbestrittenen Vorteile der z.Z. verfügbaren Kunstnetze mehren sich Berichte über Spätkomplikationen nach der Implantation. Eine Optimierung der Kunstnetze ist notwendig, bedingt aber ein standardisiertes Tiermodell zur Evaluierung der Biokompatibilität auf funktioneller und morphologischer Ebene. In der vorliegenden Studie werden z.T. handelübliche Polypropylen-und Polyesternetze in einem standardisierten Rattenmodell implantiert und detailliert morphologisch und morphometrisch analysiert. Die morphologisch-morphometrischen Daten werden in Anschluß mit der Funktion der künstlichen Bauchwand korreliert. Zusammenfassend zeigen die Daten, daß die z.Z. gebräuchlichen Netzkonstruktionen überdimensioniert sind und zu einer deutlichen Funktionseinschränkung der künstlichen Bauchwand führen. Die Funktion wird dabei entscheidend durch den Entzündungs- und Fibrosegrad, durch das Fibrosemuster und durch die Zusammensetzung der Extrazellularmatrix beeinflußt. Fibrose und Entzündung werden jedoch weniger durch das Material an sich bestimmt, sondern durch die Materialdichte,-verarbeitung und-ober-fläche. Zukünftige Netzkonstruktionen der 2. Generation sollten zur Verbesserung der funktionell-morphologisch definierten Biokompatibilität eine Reduzierung der Materialmenge und eine materialspezifische Verarbeitung anstreben.
    Notizen: Abstract Modern surgical hernia repair depends increasingly on synthetic meshes for reconstruction of the abdominal wall. Despite the undisputed advantages of the synthetic meshes currently available, reports of late complications after implantation are accumulating. It is essential that the synthetic meshes be improved, but this makes a standardized animal model necessary for evaluation of their biocompatibility on both functional and morphological levels. In the present study, commercially available polypropylene and polyester meshes were implanted in a rat model, and detailed morphological and morphometric analysis were carried out. Correlations between the morphological and morphometric data and the function of the artificial abdominal wall were then sought. In summary, the data show that the mesh constructions currently available are oversized and definitely restrict the function of the artificial abdominal wall. The degree of inflammation and fibrosis, the pattern of fibrosis, and the composition of the extracellular matrix exert decisive influences on the function. Fibrosis and inflammation are caused less by the material itself, however, than by its density, the way it is processed, and its surface. Future, that is to say second-generated, mesh constructions should be designed with the aims of reducing the amount of material used and finding material-specific processing methods in mind, to improve the functionally and morphologically defined biocompatibility.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Langenbeck's archives of surgery 382 (1997), S. 87-94 
    ISSN: 1435-2451
    Schlagwort(e): Key words Hernia repair ; Mesh ; Complications ; Biocompatibility ; Rat model ; Schlüsselwörter Hernienchirurgie ; Netz ; Komplikationen ; Biokompatibilität ; Ratte
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die moderne Hernienchirurgie bedient sich zunehmend Kunstnetzkonstruktionen zur Bauchwandrekonstruktion. Trotz der unbestrittenen Vorteile der z.Z. verfügbaren Kunstnetze mehren sich Berichte über Spätkomplikationen nach der Implantation. Eine Optimierung der Kunstnetze ist notwendig, bedingt aber ein standardisiertes Tiermodell zur Evaluierung der Biokompatibilität auf funktioneller und morphologischer Ebene. In der vorliegenden Studie werden z.T. handelübliche Polypropylen- und Polyesternetze in einem standardisierten Rattenmodell implantiert und detailliert morphologisch und morphometrisch analysiert. Die morphologisch-morphometrischen Daten werden in Anschluß mit der Funktion der künstlichen Bauchwand korreliert. Zusammenfassend zeigen die Daten, daß die z.Z. gebräuchlichen Netzkonstruktionen überdimensioniert sind und zu einer deutlichen Funktionseinschränkung der künstlichen Bauchwand führen. Die Funktion wird dabei entscheidend durch den Entzündungs- und Fibrosegrad, durch das Fibrosemuster und durch die Zusammensetzung der Extrazellularmatrix beeinflußt. Fibrose und Entzündung werden jedoch weniger durch das Material an sich bestimmt, sondern durch die Materialdichte, -verarbeitung und -oberfläche. Zukünftige Netzkonstruktionen der 2. Generation sollten zur Verbesserung der funktionell-morphologisch definierten Biokompatibilität eine Reduzierung der Materialmenge und eine materialspezifische Verarbeitung anstreben.
    Notizen: Abstract Modern surgical hernia repair depends increasingly on synthetic meshes for reconstruction of the abdominal wall. Despite the undisputed advantages of the synthetic meshes currently available, reports of late complications after implantation are accumulating. It is essential that the synthetic meshes be improved, but this makes a standardized animal model necessary for evaluation of their biocompatibility on both functional and morphological levels. In the present study, commercially available polypropylene and polyester meshes were implanted in a rat model, and detailed morphological and morphometric analysis were carried out. Correlations between the morphological and morphometric data and the function of the artificial abdominal wall were then sought. In summary, the data show that the mesh constructions currently available are oversized and definitely restrict the function of the artificial abdominal wall. The degree of inflammation and fibrosis, the pattern of fibrosis, and the composition of the extracellular matrix exert decisive influences on the function. Fibrosis and inflammation are caused less by the material itself, however, than by its density, the way it is processed, and its surface. Future, that is to say second-generated, mesh constructions should be designed with the aims of reducing the amount of material used and finding material-specific processing methods in mind, to improve the functionally and morphologically defined biocompatibility.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
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