Tennessee Gov. Phil Bredesen and Nashville Mayor Karl Dean have scheduled an announcement that is expected to feature architectural renderings of a redesigned Nashville Convention Center and a lease agreement with the Dallas-based company planning to open a medical trade center in the city. The announcement is billed as "a major investment linked to healthcare in downtown Nashville." Dallas-based Market Center Management Co. has been looking at the convention center and other downtown properties as potential sites for the medical trade center, which would showcase healthcare products and services.