Physiological Basis of the Radioisotope Renogram

A model elucidating the relationships between blood radioactivity, the renogram curve, and urine radioactivity, as a function of time, is derived. Estimation procedures have been devised which use the data from three curves at once to estimate parameters common to the three curves, and which also estimate parameters unique to the individual curves. A program has been written for the RPC 4000 computer to perform the estimation. It was found that some model in which six different exponential parameters could be justified instead of the two proposed by the model could provide a significantly better fit of the data (P \u3c .001), but that the fit under the hypothesis was still quite good

Laboratory and Clinical Studies of Cardiac Transplantation

Cardiac transplantation was carried out on four patients at the Medical College of Virginia between May and October of 1968, in an effort to salvage them from the terminal stages of otherwise uncorrectable heart disease. Despite a strikingly good early recovery from operation in each case, three of the patients died of acute homograft rejection in one to three weeks; our second case is living and well, ten months after operation, and is at this writing the world\u27s third longest survivor. The world experience to June of 1969 includes about 130 cardiac transplants. Of the first 100 patients operated on over six months ago, 20 are surviving, and the majority of these have returned to a productive existence, demonstrating the feasibility of complete rehabilitation of at least some terminal patients after cardiac transplantation. The high mortality rate--significantly higher than was anticipated--has resulted from acute and chronic homograft rejection and from the equally difficult problem of infection. Certain lessons have been learned from our own experience and from the world experience with this procedure, and these will be reviewed in an attempt to establish the current status and future potential of cardiac transplantation