3D Coronary Vessel Tree Tracking in X-Ray Projections

International audience.CTA angiography brings potentially useful information forguidance in an interventional procedure. It comes with the challenge ofregistering this 3D modality to the projection of the coronary arterieswhich are deforming with the cardiac motion. A tree-spline i.e. a treewith a spline attached to each edge and shared control points betweenthese points describes a 3D coronary tree and is able to represent itsdeformation along the time. We combine this description with a registra-tion algorithm operating between the tree-spline and the angiographicprojection of the coronary tree. It starts by the estimation of a rigidtransformation for the iso cardiac phase time followed by a non-rigiddeformation of the tree driven by the pairings formed between the pro-jection of the edges of the tree-spline and the observed x-ray projectionof the coronary arteries. The pairings are built taking into account thetree topology consistency. Anatomical constraints of length preservationis enforced when deforming the arteries. The proposed approach hasbeen evaluated with clinical data issued from ten different clinical caseswhich enabling to form twenty three different experimental conditions.Encouraging results have been ob

TGFβ/SMAD signalling modulates MLL and MLL-AF4 mediated 5-lipoxygenase promoter activation

5-Lipoxygenase (5-LO) catalyzes the initial two steps of the conversion of arachidonic acid to leukotrienes which represent a group of pro-inflammatory lipid mediators involved in immune defense reactions as well as inflammation, allergy and cancer. Transforming growth factor-β (TGFβ) and calcitriol strongly upregulate 5-LO expression during myeloid cell differentiation and MLL-AF4 has been shown to strongly activate the 5-LO promoter. Here, we investigated the role of TGFβ/SMAD signalling in 5-LO promoter activation. We identified two functional SMAD binding elements in the proximal part of the 5-LO promoter which significantly induce 5-LO promoter activity via TGFβ and SMAD3/4. Since aberrant 5-LO gene expression has been linked with mixed lineage leukemia (MLL) which is characterized by the presence of MLL fusion proteins (e.g. MLL-AF4), we also investigated the influence of TGFβ/SMADs on MLL- and MLL-AF4-mediated 5-LO promoter activation. Our data show that induction of 5-LO promoter activity by SMAD3/4 is MLL-dependent and that knockdown of the MLL complex component MEN1 attenuates the SMAD effect. Our data suggest that induction of 5-LO gene expression by TGFβ is at least in part due to stimulation of transcript initiation