Bibliothek

X
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
  • 1985-1989  (6)
  • Topography  (3)
  • LPS  (1)
  • LTC4/D4 and TxB2 synthesis  (1)
  • Stable laws  (1)
  • Survival  (1)
  • disorder  (1)
Datenquelle
Materialart
Erscheinungszeitraum
  • 1985-1989  (6)
Jahr
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Effect of bacterial endotoxin on lipoxygenase and cyclo-oxygenase metabolites by rat neutrophils and correlation with cellular functional parameters (1988)
    Springer
    Research in experimental medicine 188 (1988), S. 9-17 
    Details
    ISSN: 1433-8580
    Schlagwort(e): Endotoxin ; LPS ; Rat PMN ; LTC4/D4 and TxB2 synthesis ; PMN functions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effect ofSalmonella enteritidis endotoxin on in vitro rat neutrophil cyclo-oxygenase and lipoxygenase metabolism, phagocytic activity, superoxide (O 2 - ) generation, and microbicidal activity was investigated. Incubation of polymorphonuclear leukocytes (PMN) with 5, 25, and 50 µg of endotoxin significantly enhanced synthesis of immunoreactive (i) leukotriene (LT)C4/D4 and thromboxane (Tx)B2 (P 〈 0.001) as compared to control cells. Endotoxin 5 µg/ml produced optimal stimulation of the arachidonic acid metabolites. Calcium ionophore, A23187, significantly enhanced iLTC4/D4 and iTxB2 synthesis more than that elicited with endotoxin. Although phagocytic function was not significantly altered by endotoxin, intracellular killing ofC. albicans demonstrated enhanced microbicidal activity at 5 µg/ml of endotoxin. Superoxide generation was significantly enhanced in neutrophils stimulated with phorbol myristate acetate (PMA). Endotoxin (5 µg/ml) further potentiated superoxide generation by these cells when stimulated by PMA. These findings demonstrate that endotoxin directly enhances neutrophil iLTC4/D4 and iTxB2 synthesis. The enhanced arachidonic acid metabolism elicited by endotoxin in these cells parallels increased microbicidal activity and superoxide generation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01852089
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Polymers on disordered hierarchical lattices: A nonlinear combination of random variables (1989)
    Springer
    Journal of statistical physics 57 (1989), S. 89-139 
    Details
    ISSN: 1572-9613
    Schlagwort(e): Stable laws ; disorder ; polymer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The problem of directed polymers on disordered hierarchical and hypercubic lattices is considered. For the hierarchical lattices the problem can be reduced to the study of the stable laws for combining random variables in a nonlinear way. We present the results of numerical simulations of two hierarchical lattices, finding evidence of a phase transition in one case. For a limiting case we extend the perturbation theory developed by Derrida and Griffiths to nonzero temperature and to higher order and use this approach to calculate thermal and geometrical properties (overlaps) of the model. In this limit we obtain an interpolation formula, allowing one to obtain the noninteger moments of the partition function from the integer moments. We obtain bounds for the transition temperature for hierarchical and hypercubic lattices, and some similarities between the problem on the two different types of lattice are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01023636
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    Role of thromboxane, prostaglandins and leukotrienes in endotoxic and septic shock (1986)
    Springer
    Intensive care medicine 12 (1986), S. 116-126 
    Details
    ISSN: 1432-1238
    Schlagwort(e): Eicosanoids ; Survival ; Clinical ; Animal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Intravenous bolus endotoxin elicits a marked but transient increase in plasma TxB2 and 6-keto-PGF1α in a large number of species. A smaller, delayed and more prolonged increase in TxB2 and 6-keto-PGF1α are reported in animals with septic shock, i.e., those with fecal peritonitis or cecal ligation. Thromboxane synthetase inhibitors or antagonists attenuate endotoxin-induced acute cardiopulmonary changes, the delayed increase in serum lysosomal enzymes, fibrin/fibrinogen degradation products and the thrombocytopenia in a number of species. While these drugs increase survival of rats or mice following endotoxin they do not alter survival of rats in septic shock. These results support the hypothesis that TxA2 exerts a pathophysiologic effect in shock following bolus endotoxin. In contrast, nonsteroidal antiinflammatory drugs (NSAID) and dietary essential fatty acid deficiency increase survival of rats subjected to endotoxin shock, and survival time in models of septic shock. These results also suggest that some other cyclooxygenase product(s) is involved in septic shock due to fecal peritonitis or cecal ligation. Preliminary experimental studies indicate salutary effects of leukotriene inhibitors and antagonists in endotoxin shock and in models of acute pulmonary injury. Clinical studies have demonstrated elevated plasma TxB2 and 6-keo-PGF1α concentrations in patients with septic shock, and elevated LTD4 in pulmonary edema fluid of patients with the adult respiratory distress syndrome. In view of these clinical and experimental results, clinical trials of NSAID and/or leukotriene inhibitors/antagonists should be considered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00254925
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 4
    Digitale Medien
    Digitale Medien
    A sharp retinal image increases the topographic precision of the goldfish retinotectal projection during optic nerve regeneration in stroboscopic light (1987)
    Springer
    Experimental brain research 68 (1987), S. 319-328 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Retinotectal projection ; Topography ; Correlated activity ; Goldfish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Locally-correlated neural activity appears to play a key role in refining topographically mapped projections. The retinotectal projection of the goldfish normally regains a high degree of spatial precision after regeneration of a cut optic nerve, but it fails to do so if retinal ganglion cell activity is blocked by tetrodotoxin, or if local correlations in activity are masked by the synchronizing effect of stroboscopic light. A sharp retinal image is not normally needed for a sharp map because local correlation occurs even in darkness or diffuse light, but the possibility that a sharp image might restore local correlation and sharpen the map in stroboscopic light, though taken into account in earlier experiments, has not previously been tested. The precision of the retinotectal map was therefore studied, by retrograde transport of WGA-HRP from a standard tectal injection site and quantitative analysis of the labelled ganglion cell distribution, after regeneration of a cut optic nerve for 83–84 days in either continuous stroboscopic light or normal diurnal light. The lens of the eye was either ablated to blur the retinal image or sham-operated. Two different strobe flash patterns used in previous experiments were also compared. With the lens ablated, stroboscopic light impaired map refinement significantly, confirming previous results. A rapid, irregular flash pattern averaging about 5 Hz was rather more effective than a regular 1 Hz pattern. With the lens intact, however, neither pattern had any detectable effect. The significant gain in precision resulting from a sharp retinal image in these circumstances suggests that common mechanisms could underlie both the internal refinement of the retinotectal map and such directly experience-sensitive processes as the experimental realignment of binocular maps in the frog Xenopus, and of auditory and visual maps in the barn owl.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00248798
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 5
    Digitale Medien
    Digitale Medien
    Topographic refinement of the regenerating retinotectal projection of the goldfish in standard laboratory conditions: a quantitative WGA-HRP study (1986)
    Springer
    Experimental brain research 63 (1986), S. 409-420 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Retinotectal projection ; Regeneration ; Topography ; Goldfish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The topographic precision of the regenerating retinotectal projection of the goldfish was studied between 18 and 524 days (at 20° C) after optic nerve cut, using retrograde transport of wheatgerm agglutinin conjugated to horseradish peroxidase (WGA-HRP) from one of two standardized tectal injection sites. All labelled ganglion cells in each flat-mounted retina were plotted individually, and their degree of dispersion was assessed by a statistical method based on distance to nearest neighbour. Labelled cells in normal fish were clustered tightly, covering on average only 1.3% of the retina. Early in regeneration (18–28 days) they were widely dispersed, covering up to 75.2%, and they did not begin to form recognizable clusters at appropriate sites until about 35 days after nerve cut. Between 18 and 70 days, the proportion of retina covered by labelled cells fell dramatically, halving about every 14 days. Between 70 and 524 days, no further reduction could be demonstrated: overall, clusters remained significantly larger than normal, though a few individual retinae were virtually normal. Several others, labelled from similar single injections between 56 and 524 days after nerve cut, showed pairs of cell clusters; a sign that persistent errors in topography are common. The very wide initial scatter of labelled cells reflects a striking lack of ‘goal-directedness’ in regenerative axon growth. Extensive branching in the optic nerve, tract and tectum, for which there is already evidence, must contribute to this. Though uptake of some WGA-HRP by non-synaptic growth cones cannot be ruled out, other evidence for mislocated functional synapses at early stages encourages us to favour ‘trial and error’ synapse formation as the likely basis of map refinement.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00236860
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 6
    Digitale Medien
    Digitale Medien
    Impaired refinement of the regenerated retinotectal projection of the goldfish in stroboscopic light: a quantitative WGA-HRP study (1986)
    Springer
    Experimental brain research 63 (1986), S. 421-430 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Retinotectal projection ; Topography ; Correlated activity ; Goldfish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The retinotectal projection of the goldfish was studied after regeneration of a cut optic nerve in stroboscopic light, constant light or diurnal light, with the lens removed to blur the retinal image. Retrograde transport of wheatgerm agglutinin, conjugated to horseradish peroxidase, from a standard tectal injection site was used to measure the topographic precision of the projection. The dispersion of labelled retinal ganglion cells, which reflects this precision, was assessed by a method based on distance to nearest neighbour. In normal fish treated similarly, these cells are known to be clustered into about 1% of the retinal area. Early in regeneration, however, they are widely dispersed. The projection map then re-acquires its precision over two or three months. In diurnal light, lens ablation had no effect on refinement of the regenerated map. Constant light increased the number of labelled cells but also had no significant effect on the map. But in stroboscopic light with a continuous pseudorandom pattern of flash intervals (average rate 4.8 Hz), much less refinement was seen. Even after 70–98 days of regeneration, labelled cells remained scattered, on average, over 20% of the retinal area. These retinae were indistinguishable by several criteria from those obtained in diurnal light after only 32–39 days. Mislocated axon terminals, which are largely eliminated during the second and third months of regeneration in diurnal light, evidently persist much longer in stroboscopic light that synchronizes ganglion cell activity across the retina. These results, like previous ones obtained by blocking the transmission of activity to the tectum, support a model of map refinement based on correlation in the firing of neighbouring neurons, which may have wide application within the nervous system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00236861
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...