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Biomedical subjects

Stephan Soullier

Publications and source records attributed to Stephan Soullier.

3 recordsLinked to original sources

[Molecular mechanisms involved in kidney ischemia-reperfusion].

Acute renal failure (ARF) is still associated with high mortality. It is the consequence of a set of phenomena leading to a low glomerular filtration rate resulting, at least partly, from a misregulation of renal blood flow resulting itself from injuries at the epithelial and endothelial level. The outer medulla seems to be the region of the kidney the most affected by ischemia. Investigation at the histological level reveals a partial destruction of the renal epithelium generated by necrosis and/or apoptosis, loss of cell polarity, cell desquamation into the lumen and endothelial cell swelling. The recent advances in the comprehension of this pathology underline the major role of inflammation, which is probably responsible for the worsening and the persistence of ARF. Studies at the molecular level have pinpointed the implication of many signalling pathways such as apoptosis, G-protein signalling, various receptor and kinase activation. The characterisation of the molecular events involved in ARF should help in our approaches to prevent and treat ARF. The understanding of the adaptation mechanisms to ischemic stress (conditioning) is probably one of the most promising research area of this field in terms of medical applications.

Animals↗

Foxn1 is required for tissue assembly and desmosomal cadherin expression in the hair shaft.

The mouse nude mutation inactivates the gene encoding the Foxn1 transcription factor, causing defective hair morphogenesis. Here, we show for the first time that Foxn1 is required for proper assembly of the hair medulla, and we identify Foxn1-regulated genes by transcript profiling. One such gene encodes the desmosomal cadherin, Dsc2. Significantly, Foxn1-dependent Dsc2 expression is restricted to the hair medulla, and within these cells, Dsc2 protein is predominantly localized to specialized adhesion junctions between the cortex and the medulla. Our results reveal Foxn1 as an essential regulator of tissue assembly in the growing hair shaft and implicate Dsc2 as a downstream effector of this activity.

Animals↗

Reducing the variability in cDNA microarray image processing by Bayesian inference.

MOTIVATION: Gene expression levels are obtained from microarray experiments through the extraction of pixel intensities from a scanned image of the slide. It is widely acknowledged that variabilities can occur in expression levels extracted from the same images by different users with the same software packages. These inconsistencies arise due to differences in the refinement of the placement of the microarray 'grids'. We introduce a novel automated approach to the refinement of grid placements that is based upon the use of Bayesian inference for determining the size, shape and positioning of the microarray 'spots', capturing uncertainty that can be passed to downstream analysis. RESULTS: Our experiments demonstrate that variability between users can be significantly reduced using the approach. The automated nature of the approach also saves hours of researchers' time normally spent in refining the grid placement.

Algorithms↗