Locally Regularized Smoothing B-Snake

<p/> <p>We propose a locally regularized snake based on smoothing-spline filtering. The proposed algorithm associates a regularization process with a force equilibrium scheme leading the snake's deformation. In this algorithm, the regularization is implemented with a smoothing of the deformation forces. The regularization level is controlled through a unique parameter that can vary along the contour. It provides a locally regularized smoothing B-snake that offers a powerful framework to introduce prior knowledge. We illustrate the snake behavior on synthetic and real images, with global and local regularization.</p

Calcul De Cylindricité Basé Sur Les Moments Géométriques.

International audienc

Combined hypervolemia and hypoosmolality alter hypothalamic-pituitary-adrenal axis response to endotoxin stimulation

Changes in corticotropin (ACTH) and glucocorticoid secretion have been described during disturbances of body fluid homeostasis and attributed to alterations in arginine vasopressin (AVP) secretion from magnocellular hypothalamic neurons. In order to further characterize the mechanisms involved in the interactions between body fluid alterations and pituitary adrenal function, we manipulated osmolality and volemia in sheep under stimulation of the pituitary-adrenal axis by acute injection of endotoxin. We have recently shown that endotoxin injection induces a long-lasting release of both corticotropin releasing hormone (CRH) and AVP into hypophysial portal blood, and an early stimulation of AVP secretion into peripheral vessels, thus suggesting a joint activation of magnocellular and parvocellular neurons of the PVN. We used the same experimental model to investigate the effect of combined volume loading and plasma dilution (achieved by 1-deamino-8-D-arginine (dDAVP) administration together with infusion of 2 liters of 2.5% glucose solution) on CRH, AVP, ACTH and cortisol responses to endotoxin stimulation. In volume-loaded animals, ACTH and cortisol responses to endotoxin were significantly blunted and we observed a parallel decrease in portal CRH and jugular and portal AVP levels. These data show that hypoosmolality and/or hypervolemia reduce(s) ACTH and cortisol response to stress in sheep as in other species. They strongly suggest that this reduction in ACTH and cortisol responses to endotoxin involve not only magnocellular hypothalamic neurons secreting AVP, as usually assumed, but also PVN parvocellular neurons secreting both CRH and AVP