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DISCUSSION 
Chairman Hawthorne: Thank you Dr. 
Sandler. Do you keep these chimps in the 
squeeze cages all of the time? 
Dr. Sandler: Yes, we've not been turning 
them loose in the runs. 
Chairman: Would the pressures change 
more if you let them run around for awhile? 
Dr. Sandler : This is what we would like to 
do. But, initially we had a lot of trouble getting 
the units working. Now we have a reliable im- 
plantable telemetry unit which can operate for 
periods in excess of one year. The range of 
transmission of the telemetry units is 50 to 100 
feet which limits us to a certain extent because 
if we turn them loose in a compound, there 
would be areas in the compound where we 
would have trouble picking up a signal. This 
would require the use of a transponder or a re- 
transmitter. In other words, the animal would 
have to probably wear some little jacket or unit 
and carry something about the size of a ciga- 
rette lighter in the unit to pick up the weaker 
implanted signal and then retransmit for as far 
as we need. We have not done that particular 
part of it, that's why we've stuck with the 
squeeze cage. 
Chairman: Well I'm glad to see that the 
chimp is not habitually hypertensive. 
SOMANI, PiTAMBAR, Abbott Laboratories, 
North Chicago, 111. : I was stuck by your find- 
ings that isoproterenal did not seem to produce 
as much effect as we expect it to in other ani- 
mals. Were you anesthetizing these chimpan- 
zees ? And the response was unexpected because 
in the dog and other animals during the anes- 
thetizing stage we get an increase in cardiac 
output, increase in left ventricle pressure, in- 
crease in mean arterial pressure and it in- 
creases peripheral resistance. In looking at your 
slide, there was only an increase in peripheral 
resistance and mean arterial pressure. 
Dr. Sandler: When one studies awake and 
anesthetized dogs, one can obtain the types of 
response you mentioned here. I will agree with 
you that you could predict that isoproterenal 
would do the things that you said. But it did not 
occur in this animal and it is of interest to think 
that the chimp is not controlled or driven in the 
manner in which man or the dog is. I think, we 
find the dog could be characterized in his con- 
trol system as being primarily parasympathetic, 
man is mixed, and that most primates, and I 
think the chimp is a classic example of this, 
would be primarily sympathetically driven. 
We're seeing some evidence of this primary 
sympathetic drive in the response of isoproter- 
enal, but the small number of animals we have 
here is not enough to make any statement as 
strong as that yet. But our findings make us 
think that we should do more work in that area. 
Dr. SoMANi: Which beta blocking drug are 
you using ? 
Dr. Sandler: Propranolol. 
Dr. SoMANi: Do you have any idea about 
coronary occlusions in the chimpanzee ? 
Dr. Sandler : No. We have not done this nor 
is there anything, unless we've missed it, in the 
literature which would make us believe this. 
We're interested about coronary occlusions in 
the chimpanzee especially in evaluation of how 
good a cardiac model the chimpanzee is for 
man. We found that, first of all, the control sys- 
tem is not a direct analog. The second, that 
when we went to do angiocardiograph studies 
we found the chimp has a completely horizontal 
heart. When the chimp is laying on his back, the 
heart is just like a gun barrel, where man's 
heart position is different. We're also finding 
slight differences in the dynamic geometry with 
the contraction pattern. But, these are very 
early findings. 
J. T. Reeves, University of Kentucky, Lex- 
ington, Ky. : In your best animals, how do you 
feel that you are approaching normal in regards 
to respiration, arterial blood gases, and other 
vital measurements ? 
Dr. Sandler: We've only had four aninals 
live beyond thirty-eight weeks, but the one ani- 
mal that has survived from our first studies, 
who is now two years exactly post-op, has 
gained thirty kilo in weight. He started out 
being about forty pounds and now he's almost 
100 pounds, besides being difficult to handle. I 
think that gives us one piece of information. 
