Abstract: A system for comparing two complex entities, particularly appropriate for assisting in matching recipients with potential organ transplant donors or prostheses, utilizes a set of data corresponding to multiple diverse parameters representing a first complex entity, graphically represented on a helical structure having a discrete primary zone for each parameter and a series of secondary zones within each primary zone to establish scale means for quantitative representation of the data. The data is represented in a visual manner by means of shading in the secondary zones, with the shading increasing in hue and density with increasing distance of the secondary zones from the longitudinal axis of the helical structure, and terminating at a quantitative value for each parameter.

Abstract: In combination with a device adapted for at least partial implantation in a living body to perform a function with respect to that body such as introducing a material into the body, relieving the body of a material, monitoring a condition within the body, or introducing electrical stimulus into the body, servicing apparatus is provided in association with the device for maintaining the device in effective operating condition. The device and servicing apparatus may be arranged in a single housing such that a portion of the device extends from the housing into operable position in the body, in separate but operably connected housings, or the servicing apparatus may be split between the device and a separate housing.