DATTA questions are addressed by physician consultants with expertise on the clinical issue being evaluated. These consultants are selected from a DATTA panel that includes more than 1000 physicians. Members of the DATTA panel have been nominated after solicitation by medical specialty societies, by medical schools throughout the AMA's Section on Medical Schools, by all councils and sections of the AMA, and by state medical societies. Solicitation for nominations specifies only that those nominated be adjudged by their peers as being experts in their particular field of medicine. Nominees are confirmed as members of the DATTA panel when their professional credentials have been verified. Membership or affiliation with the American Medical Association is not a consideration. Expertise regarding and selection for response to particular questions are determined by key word sampling of designated physician specialty, subspecialty, or special interest. An effort is made to reflect a national geographic spectrum of diverse practice settings. This report is not intended to be construed or to serve as a standard of medical care. Standards of medical care are determined on the basis of all of the facts and circumstances involved in an individual case and are subject to change as scientific knowledge and technology advance and patterns evolve. This report reflects the views of the DATTA panelists and reports in the scientific literature as of Aug 2,1987. DATTA-related inquiries should be submitted to