Fluorescein angiography of canine conjunctival auto- and allografts. Analysis by sequential, still photographic recording of the spreading of fluorescence over the graft surfaces following intravenously administered fluorescein.

Two autologous and 4 allogeneic conjunctival grafts have been transplanted to the corneal-scleral region in 6 dogs. The animals with the autografts and 2 of the allografts were untreated, while the animals with the other 2 allografts were treated with azathioprine and prednisolone. The grafts were followed with daily sequential, still photographic recording of the spreading of the fluorescence over the graft surfaces after fluorescein sodium had been given intravenously. A motordriven camera, with automatically timed exposures at very short intervals down to 1 sec, was used in combination with a fast recycling flash unit. The behaviour of the circulation seemed to be the same in auto- and in allografts during the first 8 days of healing. One day before showing signs of rejection at oridinary inspection, the two untreated allografts, on photographic analysis of the spreading of fluorescence, showed minute areas of non-fluorescence in an early stage of the procedure. The same type of local impairment of the circulation, manifested by slower uptake of dye in limited areas, was noted in the treated allografts, appearing 2-3 days before severe signs of rejection were noted at orinary inspection. These areas, however, gradually filled with dye during the further course of the test, to such a degree that the irregularities in the spreading of the fluorescence might easily have been overlooked in an oridinary fluorescein test. The disturbance of the circulation gradually increased during the course of the rejection and, at the stage when changes were observed at ordinary inspection, the circulation was severely impaired, as indicated by a complete non-appearance of fluorescence in certain areas, or in the whole graft. It is suggested that the modification of the classic fluorescein test described here, in detecting the early circulatory irregularities, indicates more precisely the start of the rejection process than do the criteria of allograft rejection used so far, and that it is, therefore, a sensitive means of evaluating the effects of various immunosuppressive procedures.