JAMES D. HARDY 
339 
ANTERIOR 
Rr. 
DOG # 8 
ONE STAGE BILATERAL REPLANT 
JAN. 14 / 70 
PRE -OP 
DOG # 8 
ONE STAGE BILATERAL REPLANl 
FEB 3/70 
ONE WEEK POST-OP 
Figure 13. — Lung scans before and one week following bilateral lung replantation at one operation. 
azathioprine, prednisone and mediastinal radia- 
tion. At the present time, we have one animal 
surviving 7 months after simultaneous bilateral 
lung allotransplantation, the immunosuppres- 
sion therapy having consisted of prednisone and 
antilymphocyte serum (Figures 15 and 16) . 
Bilateral Lung Allotransplantation 
The detection of lung rejection, when only one 
lung was allografted with one of the recipient's 
own lungs remaining intact, had always posed a 
problem. Since the animal could readily survive 
on his remaining lung, one had to resort to 
studies such as roentgenograms, scans, and 
differential bronchospirometry to estimate the 
function of the allografted lung.^^'*'^ Even with 
these measures, however, the precise functional 
contribution of the allograft lung was fre- 
quently in doubt. In marked contrast, the ani- 
mal that has received two allotransplants is 
clearly surviving completely on allotrans- 
planted tissue. Thus, we consider the bilateral 
simultaneous allotransplanted animal to repre- 
sent the optimal model for future studies of im- 
munosuppressive regimens to prevent lung al- 
lograft rejection. In such animals a routine 
monitoring of chest x-ray, lung scans and ar- 
terial blood gas values can give much valid 
information regarding the pulmonary function 
of the recipient. The risky techniques such as 
bronchospirometry which require anesthetiza- 
tion of the animal are thus avoided. As in- 
dicated above, there is at present no satisfactory 
method for identifying the degree or rapidity 
of rejection of a single lung allotransplant when 
the animal's own lung remains in place. The ef- 
fectiveness of ventilation and perfusion can be 
measured by radioisotope scans, bronchospiro- 
metry and arteriograms, but it is difficult to dif- 
ferentiate atelectasis, pneumonitis, or ischemic 
