36 research outputs found
Chemoattractant Receptor Homologous to the T Helper 2 Cell (CRTH2) Is Not Expressed in Human Amniocytes and Myocytes
BACKGROUND: 15-deoxy-Δ 12,14- Prostaglandin J2 (15dPGJ2) inhibits Nuclear factor kappa B (NF-κB) in human myocytes and amniocytes and delays inflammation induced preterm labour in the mouse. 15dPGJ2 is a ligand for the Chemoattractant Receptor Homologous to the T helper 2 cell (CRTH2), a G protein-coupled receptor, present on a subset of T helper 2 (Th2) cells, eosinophils and basophils. It is the second receptor for Prostaglandin D2, whose activation leads to chemotaxis and the production of Th2-type interleukins. The cellular distribution of CRTH2 in non-immune cells has not been extensively researched, and its identification at the protein level has been limited by the lack of specific antibodies. In this study we explored the possibility that CRTH2 plays a role in 15dPGJ2-mediated inhibition of NF-κB and would therefore represent a novel small molecule therapeutic target for the prevention of inflammation induced preterm labour. METHODS: The effect of a small molecule CRTH2 agonist on NF-κB activity in human cultured amniocytes and myocytes was assessed by detection of p65 and phospho-p65 by immunoblot. Endogenous CRTH2 expression in amniocytes, myocytes and peripheral blood mononuclear cells (PBMCs) was examined by PCR, western analysis and flow cytometry, with amniocytes and myocytes transfected with CRTH2 acting as a positive control in flow cytometry studies. RESULTS: The CRTH2 agonist had no effect on NF-κB activity in amniocytes and myocytes. Although CRTH2 mRNA was detected in amniocytes and myocytes, CRTH2 was not detectable at the protein level, as demonstrated by western analysis and flow cytometry. 15dPGJ2 inhibited phospho-65 in PBMC'S, however the CRTH2 antagonist was not able to attenuate this effect. In conclusion, CRTH2 is not expressed on human amniocytes or myocytes and plays no role in the mechanism of 15dPGJ2-mediated inhibition of NF-κB
The what and why of perceptual asymmetries in the visual domain
Perceptual asymmetry is one of the most important characteristics of our visual
functioning. We carefully reviewed the scientific literature in order to examine
such asymmetries, separating them into two major categories: within-visual field
asymmetries and between-visual field asymmetries. We explain these asymmetries
in terms of perceptual aspects or tasks, the what of the
asymmetries; and in terms of underlying mechanisms, the why of
the asymmetries. Tthe within-visual field asymmetries are fundamental to
orientation, motion direction, and spatial frequency processing. between-visual
field asymmetries have been reported for a wide range of perceptual phenomena.
foveal dominance over the periphery, in particular, has been prominent for
visual acuity, contrast sensitivity, and colour discrimination. Tthis also holds
true for object or face recognition and reading performance. upper-lower visual
field asymmetries in favour of the lower have been demonstrated for temporal and
contrast sensitivities, visual acuity, spatial resolution, orientation, hue and
motion processing. Iin contrast, the upper field advantages have been seen in
visual search, apparent size, and object recognition tasks. left-right visual
field asymmetries include the left field dominance in spatial (e.g.,
orientation) processing and the right field dominance in non-spatial (e.g.,
temporal) processing. left field is also better at low spatial frequency or
global and coordinate spatial processing, whereas the right field is better at
high spatial frequency or local and categorical spatial processing. All these
asymmetries have inborn neural/physiological origins, the primary
why, but can be also susceptible to visual experience, the
critical why (promotes or blocks the asymmetries by
altering neural functions)