Radioiodinated rose bengal kinetics in extrahepatic biliary obstruction and hepatic homograft rejection in the dog.

Three groups of animals were studied: group 1, six normal control dogs; group 2, six dogs that had ligation of the common bile duct; group 3, six dogs that had received orthotopic hepatic homografts. The dogs in the last group received postoperative immunosuppression with azathioprine 1-8 mg/kg/day. The radioisotope studies were carried out one-three times weekly, for one month in the animals of group 2 and until death of the animal of rejection or other causes in group 3. Following intravenous injection of 200 micro curies of the rose bengal I 131, the intravascular retention was assessed by monitoring radioactivity over the heart with a scintillation camera and data storage system. Liver uptake and bowel appearance of the radioisotope was followed by serial scintiphotos. Intravascular retention was expressed in percentage as the ratio between the activity at 20 vs 5 min after the isotope injection. Standard biochemical liver functi6n tests were performed frequently, and postmortem liver specimens were studied with light microscopy.