Histologic sections of the aortic arches from guinea pigs were stained with nile red to verify the possibility of quantitating the earliest changes in the arterial wall. Nile red fluorescence intensity was quantitated by conversion to electric signal. Fluorescence in a group fed cholesterol and casein was significantly higher than that in a control group. Its dependence on the logarithm of serum cholesterol concentrations between 1.33 and 7.67 mmol/l was found. Small fluorescence intensity differences far beyond the possibilities of visual observation were detected by the method.

Institute of Human Nutrition Bratislava Czechoslovakia