7 research outputs found
PACAP application improves functional outcome of chronic retinal ischemic injury in rats – evidence from electroretinographic measurements
Retinoprotective effects of pituitary adenylate cyclase activating polypeptide (PACAP) are well-known and have been demonstrated in various pathological conditions, such as diabetic retinopathy, excitotoxic retinal injury, UV light-induced degeneration and ischemic retinal lesion. The neuronal degeneration observed in the different retinal layers under the above pathological conditions can be successfully decreased by PACAP, however, whether this morphological improvement is also reflected in functional amelioration remains unknown. Therefore, our purpose was to investigate the protective effect of PACAP on the rat retina after bilateral common carotid artery occlusion (BCCAO) with electroretinography (ERG) to parallel the functional data with the previous morphological and neurochemical observations. Control eyes received saline treatment while PACAP was injected into the vitreous space of the other eye immediately after the induction of ischemia. Retinal damage and protective effects of PACAP were quantified by the changes in the wave forms and amplitudes. On postoperative days 2 and 14 several parameters were assessed with special attention to the changes of b wave. The results confirm that the previously described morphological protection induced by PACAP treatment is reflected in functional improvement in ischemic retinal lesions
Heat shock partially dissociates the overlapping modules of the yeast protein-protein interaction network: a systems level model of adaptation
Network analysis became a powerful tool in recent years. Heat shock is a
well-characterized model of cellular dynamics. S. cerevisiae is an appropriate
model organism, since both its protein-protein interaction network
(interactome) and stress response at the gene expression level have been well
characterized. However, the analysis of the reorganization of the yeast
interactome during stress has not been investigated yet. We calculated the
changes of the interaction-weights of the yeast interactome from the changes of
mRNA expression levels upon heat shock. The major finding of our study is that
heat shock induced a significant decrease in both the overlaps and connections
of yeast interactome modules. In agreement with this the weighted diameter of
the yeast interactome had a 4.9-fold increase in heat shock. Several key
proteins of the heat shock response became centers of heat shock-induced local
communities, as well as bridges providing a residual connection of modules
after heat shock. The observed changes resemble to a "stratus-cumulus" type
transition of the interactome structure, since the unstressed yeast interactome
had a globally connected organization, similar to that of stratus clouds,
whereas the heat shocked interactome had a multifocal organization, similar to
that of cumulus clouds. Our results showed that heat shock induces a partial
disintegration of the global organization of the yeast interactome. This change
may be rather general occurring in many types of stresses. Moreover, other
complex systems, such as single proteins, social networks and ecosystems may
also decrease their inter-modular links, thus develop more compact modules, and
display a partial disintegration of their global structure in the initial phase
of crisis. Thus, our work may provide a model of a general, system-level
adaptation mechanism to environmental changes.Comment: 24 pages, 6 figures, 2 tables, 70 references + 22 pages 8 figures, 4
tables and 8 references in the enclosed Supplemen