K. T. LEE, J. JARMOLYCH, D. N. KIM AND W. M. LEE 
97 
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Figure 3. — Low power light micrograph of one of the 
points of near-occlusion of a coronary artery by a 
proliferative lesion. Foamy, fat-filled cells can be 
seen, mainly in the media, but most of the lesion is 
made up of smooth muscle cells. Severe diet-fed, X- 
irradiated swine. 
weeks or longer after the first x-irradiation 
showed spindle cell intimal SMC proliferation 
of one or two cells thick. This degree of cellular 
proliferation is a common finding even in nor- 
mal control swine. Acute radiation vasculitis af- 
fecting capillaries in rabbit heart as reported 
by Fajardo and Steward^ was not seen in our 
x-irradiated swine. 
Electron micrographs of coronary lesions 
showed extensive proliferation of SMC and a 
large amount of collagen (Figure 8). Many of 
the SMC were filled with lipid. These features 
are also seen in human atherosclerosis but the 
amount of lipid in SMC is greater in the rapidly 
produced coronary lesions in the swine. 
The coronary angiograms showed extensive 
luminal narrowing of all coronary arteries 
(Figure 9 A, B, C, D). 
In one swine fed the severe diet in Series I, 
electrocardiographic evidence suggesting my- 
ocardial infarction was obtained and this was 
later confirmed anatomically. Isoelectric or in- 
verted T waves were common in swine even be- 
fore they were put on experimental diets. 
RESULTS— SERIES II 
The studies in Series II have not been com- 
pleted as yet and only the results obtained thus 
X 
Figure 4. — Very low-power light micrograph of a cor- 
onary artery in the epicardial fat. The lesion is simi- 
lar to that in Fig. 3 but shows, in addition, an area of 
hemorrhage in the intima and media (dark area at 
lower right). Severe diet-fed, X-irradiated swine. 
Figure 5. — -Very low power light micrograph of a cor- 
onary artery with a lesion similar to those in Figs. 3 
and 4 but in addition showing extensive calcium de- 
posits in the outer intima and inner media. Severe 
diet-fed, X-irradiated swine. 
