C. STOUT AND F. BOHORQUEZ 
855 
Figure 14. — (Z 497) Chimpanzee (Pan troglodytes). 
Nine-year old female. Hypocellular, lipid-rich plaque 
from the Intracranial internal carotid artery. H & E 
160. (Reproduced Avith permission from Exp. Molec. 
Path., Academic Press, New York). 
in appropriate organs or vascular beds. The ef- 
fects of various therapeutic agents on specific 
vascular beds could then be measured. In addi- 
tion, portions of the central nervous system 
could be chronically stimulated to produce cer- 
tain emotional states or behaviour patterns, 
with parallel measurements of vasomotor tone 
in appropriate vascular beds, and so on. 
SUMMARY 
The material presented was gathered during 
a five-year period from autopsies on animals 
dying in the Oklahoma City Zoo and the psycho- 
logical research laboratory of Dr. W. B. Lem- 
mon at the University of Oklahoma. Aortas 
and epicardial coronary arteries from large 
hearts were removed, flattened on cardboard, 
stained with Sudan IV and graded for intimal 
involvement using a modification of the method 
originally described by Holman. Contiguous mi- 
croscopic sections of the various arterial lesions 
were stained with Oil Eed 0, H & E and Weig- 
ert's elastic stain. Typical atherosclerotic le- 
sions were found in many of the birds, and 
smaller atherosclerotic lesions were found in a 
variety of other mammals, including anteaters, 
aardvarks and a Zebu cow. Atherosclerotic le- 
sions were also present in non-human primates, 
particularly squirrel monkeys and chimpanzees. 
Chimpanzees were the only animals in which 
significant atherosclerotic lesions were present 
in the large coronary and cerebral arteries. 
None of these lesions were of clinical impor- 
tance, however. Proliferative intimal lesions 
consisting primarily of smooth muscle cells 
were found in almost every species examined. 
In seals and sealions, these lesions were distrib- 
uted in the aorta in a fashion similar to that 
seen in atherosclerosis in man. It was interest- 
ing that no lipid was present in the lesions of 
the seals and sealions, particularly since lipid 
Figure 15. — A. (Z 446) Sea lion (Zalophus californi- 
anus). Young adult male. Small lipid-free intimal 
plaque composed of smooth muscle cells. H & E x 
160. 
B. (Z 415) Sea lion (Zalophus californianus) . 
Young adult female. Large lipid-free musculoelas- 
tic intimal plaque. Weigert's elastic stain x 25. 
(Reproduced with permission from Amer. J. Path., 
Harper and Row, Hagerstown, Maryland), 
