[Pyoderma gangrenosum revealing Takayasu's arteritis].

Background: Pyoderma gangrenosum is a form of neutrophilic dermatosis often associated with inflammatory disease or blood dyscrasias. We report a case of pyoderma gangrenosum revealing Takayasu's arteritis.

Observation: A 26 year-old woman was followed since 2002 for pyoderma gangrenosum occurring during pregnancy and regressing under general corticosteroids.

Non-linear analysis of the arterial pulsatile flow: assessment of a model allowing a non-invasive ultrasonic functional exploration.

Ultrasonic measurements and modelling of blood flow in large vessels allows non-invasive evaluation of clinically interesting hemodynamic variables. To this aim, a non-linear mathematical model for the pulsatile arterial flow is proposed using the approximation of "local flow" theory. The model requires only measurements of instantaneous radius and centre-line blood velocity, and the knowledge of the tube distensibility to calculate blood velocity profiles, pressure gradient and wall shear stress.