The present invention relates to medical devices that are inserted or implanted into patients and that have antimicrobial coatings that release free radicals into the vicinity of the device. The GLP-1 can be self-administered, and can be administered in one or more doses, as needed, on an intermittent or continuous basis, to optimize metabolism in cardiac tissue and to prevent cardiac damage associated with ischemia. A plunger assembly is slidably mounted to the housing adjacent the second end of the housing and in the direction transverse to the channel axis. The user would remove the shelf 16 from the stored position and slide the tongues 38 into the grooves until the covers 36 engage the tops 30 for supporting the shelf 16 in the cantilevered position. The accumulator has increased tray capacity because of the multiple tray-holding cages and the two transverse legs of the drive path.