Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Distribution Properties of Benzene Derivatives. III. On the Kinetics of the Diffusion-controlled Distribution of Mono- and Disubstituted Benzene Derivatives in the System n-Octanol/WaterThe kinetics of the diffusion-controlled distribution of 22 mono- and disubstituted benzenes in the solvent system n-octanol/water were investigated spectrophotometrically in the UV-VIS range at various temperatures between 288 and 333 K.The first-order rate constants k1 and k2 and the activation parameters were determined graphically.In this way, an interesting deviation from theory could be observed in the temperature range from 300 up to 308 K, which is discussed on the basis of known anomalies of water at the interface.Studies on relationships between rate constants (lg k1, lgk2) and hydrophobicity (lgP) show a nearly constancy of k1, while the rate of transport from the organic to the aqueous phase (k2) strongly depends on hydrophobicity described by lgP.The calculated regression equations correspond to analogous relationships found for mechanically influenced distributions and can therefore be explained by the same kinetical model.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: 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.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: 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
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1435-2451
    Keywords: Hernia repair ; Mesh ; Complications ; Biocompatibility ; Rat model ; Hernienchirurgie ; Netz ; Komplikationen ; Biokompatibilität ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: 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.
    Notes: 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.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1435-2451
    Keywords: Key words Hernia repair ; Mesh ; Complications ; Biocompatibility ; Rat model ; Schlüsselwörter Hernienchirurgie ; Netz ; Komplikationen ; Biokompatibilität ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: 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.
    Notes: 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.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...