Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Rat  (2)
  • X-ray solution scattering  (2)
  • 1
    ISSN: 1432-2277
    Schlagwort(e): Key words Implantation model ; Aortic valves ; Valve dysfunction ; Rejection ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Structural failure of heart valve allografts may be related to technical factors or immunological reactions. To circumvent nonimmunological factors a new rat implantation model was developed to study whether alloreactivity results in histopathological changes and valve dysfunction. Syngeneic (WAG-WAG, DA-DA) and allogeneic (WAG-BN, WAG-DA) transplantation was carried out using this new technique, and the function of explanted valves was assessed 21 days later by retrograde comptence testing. Additionally, grafts were examined using standard histological and immunohistochemical techniques. There was no leakage during retrograde injection in nine of tem syngeneic and two of ten allogeneic grafts. Microscopically, syngeneic valves appeared normal without fibrosis or intimal thickening, although CD8+ lymphocytes and macrophages were found in necrotic myocardial rim and adventitia. In contrast, allogeneic valves were deformed and noncellular, with extensive infiltration of CD4+, CD8+ and CD68+ cells in adventitia and media. Absence of fibrosis and intimal thickening in syngeneic transplanted valves indicated circumvention of nonimmunological factors. Allogeneic valve transplantation induces cellular infiltration in the graft with subsequent graft failure.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    Springer
    European biophysics journal 17 (1989), S. 245-255 
    ISSN: 1432-1017
    Schlagwort(e): X-ray solution scattering ; synchrotron radiation ; electric dichroism ; chicken erythrocyte chromatin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Physik
    Notizen: Abstract Electric dichroism and X-ray scattering measurements on solutions of uncondensed and condensed chicken erythrocyte chromatin were interpreted on the basis of model calculations. Information about the state of uncondensed fibers in the conditions of electric dichroism measurements was obtained from scattering patterns recorded as a function of pH, in the presence of spermine and at very low monovalent cation concentrations. Electric dichroism measurements on a complex of uncondensed chromatin with methylene blue were made to determine the contribution of the linker and of the nucleosomes to the total dichroism. A new approach to calculate the dichroism from realistic structural models, which also yields other structural parameters (radius of gyration, radius of gyration of the cross-section, mass per unit length) was used. Only a restricted range of structures is simultaneously compatible with all experimental results. Further, it is shown that previous interpretations of dichroism measurements on chromatin were in contradiction with X-ray scattering data and failed to take into account the distribution of orientation of the nucleosomes in the fibers. When this is done, it is found that the linker DNA in chicken erythrocyte and sea urchin chromatin must run nearly perpendicularly to the fibre axis. Taken together with the dependence of the fibre diameter on the linker length, these results provede the strongest evidence hitherto available for a model in which the linker crosses the central part of the fibre.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    Springer
    European biophysics journal 16 (1988), S. 177-185 
    ISSN: 1432-1017
    Schlagwort(e): X-ray solution scattering ; synchrotron radiation ; sea urchin chromatin ; solubility ; condensation ; electric dichroism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Physik
    Notizen: Abstract Comparison between the internucleosomal distance found by X-ray solution scattering for chicken erythrocyte (23 nm) and sea urchin (30 nm) chromatin indicates that this distance is proportional to the linker length. The diameter of the condensed sea urchin chromatin fibers is about 45 nm which is significantly larger than in chicken erythrocyte chromatin (35 nm). Trivalent cations (Gd, Tb, Cr) and the polyamines spermine and spermidine were found to induce compaction at much lower concentrations than the divalent cations but Gd, Tb and Cr induce aggregation before full compaction of the fibers. The influence of hydrogen bonding is illustrated by comparison of the effects of NaCl, ammonium chloride and alkylammonium chlorides on condensation. Solubility experiments indicate that there is a nearly linear dependence of the Mg-- concentration at which precipitation occures on chromatin concentration and confirm the differences between cations observed by X-ray scattering. The chicken erythrocyte chromatin samples were further characterized by their reduced electric dichroism. The values found are consistent with the model derived from X-ray scattering and are compared with those reported in the literature.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Surgical endoscopy and other interventional techniques 10 (1996), S. 490-494 
    ISSN: 1432-2218
    Schlagwort(e): Laparoscopy ; Rat ; Tumor take ; Weight loss ; Pneumoperitoneum ; Bowel resection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: The ability of laparoscopic techniques to treat malignant disease is controversial. We developed a rat model to assess metabolic and oncological effects of laparoscopic surgery. Methods: Experiment I. The postoperative body weight in 10 rats having laparoscopic bowel resection (group I), 10 rats having open bowel resection (group II) and 5 rats having anesthesia only (group III) was determined. Experiment II. Tumor take was scored in 11 rats having laparoscopic bowel resection (group IV), 11 rats having open bowel resection (group V), 6 rats having CO2 pneumoperitoneum without bowel resection (group VI) and 6 rats having anesthesia only (group VII). All rats had CC531 cancer cells injected intraperitoneally postoperatively. Results: Experiment I. Body weight loss in group I compared to group II (p〈0.036). Rats of group III lost no weight postoperatively. Experiment II. Tumor take was less in the subcutis (p=0.005), parietal peritoenum (p〈0.001) and bowel anastomosis (p=0.021) in group IV compared to group V. Tumor take was significantly greater at all sites except for subcutis in group VI compared to VII (all p〈0.022). Conclusions: Laparoscopic surgery is associated with less postoperative weight loss and less tumor take compared to open surgery. CO2 insufflation appears to increase tumor take.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...