A method and apparatus for clearing memory, or portions thereof, in a fast and efficient manner begins by representing a group of memory locations by a representative value. An endovascular device has an elongate body with a proximal end and a distal end; a non-imaging ultrasound transducer on the elongate body; and an endovascular electrogram lead on the elongate body in a position that, when the endovascular device is in the vasculature, the endovascular electrogram lead is in contact with blood. Translation of the title and the abstract as they were when originally filed by the Applicant. Another preferred method comprises, in part, contacting a cell with a vector comprising first and second recombining sites in antiparallel orientations such that the vector is internalized by the cell.