20 
CARDIAC MODELS 
49. St. Clair, R. W., MacNintch, J. E., Middleton, 
C. C, Clarkson, T. B., and Lofland, H. B. 
Changes in serum cholesterol levels of squirrel 
monkeys during importation and acclimation. Lab. 
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50. Middleton, C. C, Clarkson, T. B., Lofland, H. B., 
and Prichard, R. W. Diet and atherosclerosis of 
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51. Maruffo, C. a. and Portman, O. W. Nutritional 
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1968. 
52. Clarkson, T. B., Lofland, H. B., Bullock, B. C, 
and Goodman, H. O. Genetic control of plasma 
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53. Lofland, H. B., Clarkson, T. B., St. Clair, R. W., 
and Lehner, N. D. M. Studies on the regulation of 
plasma cholesterol levels in squirrel monkeys of 
two genotypes. J. Lipid Res. 1971. (In Press) 
54. DiETSCHY, J. M., and Wilson, J. D. Cholesterol 
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synthesis in various tissues and mechanisms of con- 
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55. Wilson, J. D. Biosynthetic origin of serum choles- 
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187, 1968. 
56. Lofland, H. B., Clarkson, T. B., and Bullock, 
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57. St. Clair, R. W., Lofland, H. B., and Clarkson, 
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58. Webster, W. S., Clarkson, T. B., and Lofland, 
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59. Lehner, N. D. M., Clarkson, T. B., and Lof- 
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DISCUSSION 
Chairman Kezdi: Thank you Dr. Clarkson. 
C. Grant La Faroe, Children's Hospital 
Medical Center, Boston, Mass. : The non-human 
primates have always been very appealing to 
everybody because they are readily available 
and cheap in spite of the fact that they are not 
very consistent. While I grant you that the per- 
fect model is worth any price, can you give us 
an idea of how expensive they are? 
T. B. Clarkson : Yes, I can give approximate 
figures. Squirrel monkeys cost about $40 to $45, 
cebas monkeys about $45 to $50, and adult size 
rhesus monkeys perhaps $75 to $80. 
D. M. Kramsch, Boston University: (Ques- 
tion on cholesterol in milk. ) 
T. B. Clarkson: You mean: have we exam- 
ined whether the amount of cholesterol in the 
milk makes any difference? Well, this study is 
underway at the moment. I don't feel that I'm 
clear enough on the results to make a comment 
on that matter. We do have some hand-reared 
animals with and without cholesterol. We 
should be able to piece that together fairly soon. 
P. Somani, Abbott Laboratories, North Chi- 
cago: I was struck by the slide of the heart 
where the coronary arteries were very well oc- 
cluded and yet the myocardium seemed normal. 
Is that peculiar to rhesus monkey, or what is 
the reason for this ? Do you have some explana- 
tion? 
T. B. Clarkson : Yes ; my explanation is that 
slides can be deceptive if you show them fast 
enough. These arteries are deceptive insofar as 
the lipid which you see is correlated with the 
adventitial accumulation of lipids. The lumens 
are not as stenosed as you would think they 
might be from the gross photograph. They're 
more often of the nature that I showed you in 
the histologic section, with about 75% occlusion 
of the lumen. In effect, a fixed preparation. But 
I think these gross photographs of Macacs are 
deceptive because of the amount of adventitial 
lipids. I expect that Dr. Kramsch would agree. 
