Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • 2000-2004  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Mitogen-Activated Protein Kinase Mediates Epidermal Growth Factor-Induced Morphogenesis in Pituitary GH3 Cells (2002)
    Oxford, UK : Blackwell Science, Ltd
    Journal of neuroendocrinology 14 (2002), S. 0 
    Details
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Epidermal growth factor (EGF) causes pituitary GH3 cells to change from their normal predominantly rounded morphology to much more elongated cells with extensive filopodia, and this effect is accompanied by a parallel increase in cell volume. In view of this, and because EGF receptor expression is increased in some pituitary tumours, we examined the mechanism of this EGF-induced morphological effect as it may play a role in tumour invasiveness. The effect of treatment of the cells with EGF (1 nm, 4 days) was determined visually (expressed as percent non round cells) and by measuring the cell volume by Coulter Counter analysis. EGF treatment caused the cells to change their morphology with percent non round cells increasing from 37% in control cells to 74% in EGF-treated cultures; this was accompanied by a parallel increase in cell volume. Treatment of the cells with EGF in the presence of the MEK1 inhibitor (PD98059) completely blocked the EGF-induced morphological changes, showing that activation of the mitogen-activated protein kinase (MAPK) pathway is necessary to mediate this effect. Transfection of the cells with a constitutively activated mutant of MEK1 produced a similar morphological change to that produced by EGF treatment, with the proportion of non round cells increasing to 62% with a parallel increase in cell volume compared to cells transfected with the empty vector, demonstrating that direct activation of MAPK pathway is sufficient to mediate the observed morphological effects. The effects produced by activated MEK1 transfection could be blocked by PD98059. EGF had opposing effects on prolactin and growth hormone (GH) secretion by the cells, increasing prolactin release and inhibiting GH release. Transfection of the cells with activated MEK1 produced similar effects on hormone release as EGF treatment. In conclusion, the morphological effects of EGF on GH3 cells are mediated by activation of the MAPK pathway as blockade of this pathway abolished the observed effect, and direct activation of this pathway by transfection with an activated mutant of MEK1 was able to duplicate these effects. This mechanism may contribute to the growth and possibly local invasiveness of some pituitary tumours that express the EGF receptor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.0007-1331.2002.00786.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Joseph Bryennius and the text of Marcus Aurelius’ Meditations (2000)
    Cambridge : Cambridge University Press
    The @classical quarterly 50 (2000), S. 584-596 
    Details
    ISSN: 0009-8388
    Source: Cambridge Journals Digital Archives
    Topics: Classical Studies
    Notes: A neglected source for the text of Marcus Aurelius’ Meditations is to be found in the writings of the Byzantine theologian Joseph Bryennius, who seems to have been born about 1350 (details of his early life are obscure) and to have died before the Council of Florence (1438), probably in 1430/1. He was a monk who was also a scholar, a theologian, and an ecclesiastical diplomat. He spent the years 1382–1402 in Crete (then under Venetian rule), and was sent in 1406 on a mission of ecclesiastical diplomacy to Cyprus. Otherwise the greater part of his life was spent in Constantinople; from about 1402 to 1406 he lived at the monastery of Stoudios, from 1416 to 1427 at that of Charsianeites. He was a court preacher, and as a theologian upheld the claims of the Greek Church against the Roman; among his published works are twenty-one Discourses on the Trinity maintaining the Greek Orthodox position.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1093/cq/50.2.584
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The onset of Darcy-Bénard convection in an inclined layer heated from below (2000)
    Springer
    Acta mechanica 144 (2000), S. 103-118 
    Details
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary We present an, account of the linear instability of Darcy-Boussinesq convection in a uniform, unstably stratified porous layer at arbitrary inclinations α from the horizontal. A full numerical solution of the linearized disturbance equations is given and the detailed graphical results used to motivate various asymptotic analyses. A careful study shows that at large Rayleigh numbers two-dimensional instability can only arise when α≤31.30°. However it is also demonstrated that the maximum inclination below which this instability may be possible is the slightly greater value of 31.49° which corresponds to a critical Rayleigh number of 104.30.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01181831
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The Effect of Time-Periodic Surface Temperature Oscillations on Free Convection from a Vertical Surface in a Porous Medium (2000)
    Springer
    Transport in porous media 39 (2000), S. 119-130 
    Details
    ISSN: 1573-1634
    Keywords: unsteady ; natural convection ; vertical surface
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract In this paper, we consider the unsteady free convection boundary layer flow which is induced by time-periodic variations in the surface temperature of a vertical surface embedded in a porous medium. The basic steady flow is that of a power-law distribution where the surface temperature varies as the nth power of the distance from the leading edge. Small-amplitude time-periodic disturbances are added to this basic distribution. Both the low- and high-frequency limits are considered separately, and these are compared with a full numerical solution obtained by using the Keller-box method. Attention is restricted to the cases n≤1; when n=1, the flow is locally self-similar for any prescribed frequency of modulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006692124087
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...