We investigated the interaction between low density lipoproteins (LDL) and cultured Mahlavu hepatoma cells, which are a novel model of human hepatocytes. When Mahlavu cells were incubated with ¹²⁵I-LDL at 4°C, ¹²⁵I-LDL bound to the cells with high affinity, showing saturation kinetics (K_d=2×10^-8M, B_max=170ng LDL protein/mg cell protein).
At 37°C, ¹²⁵I-LDL bound to Mahlavu cells was subsequently internalized and degraded. When incubated with 20-fold concentrations of cold VLDL, LDL and HDL, the degradation of ¹²⁵I-LDL was inhibited by 56%, 87% and 25%, respectively, indicating that these binding sites were most specific for LDL.
The degradation of ¹²⁵I-LDL was inhibited by 100μM chloroquine and 10mg/ml diethylaminoethoxyhexestrol (DH), both of which are strong inhibitors of lysosomal hydrolase, suggesting the LDL degradation site was located in the lysosome.
The rate of cholesterol synthesis was inhibited, while the rate of cholesterol esterification was increased by adding LDL to the culture medium in these cells. However, chloroquine reversed both the inhibition of cholesterol synthesis and the enhancement of cholesterol esterification by LDL.
These results suggest that Mahlavu cells have an LDL-receptor pathway which should be identical to those in other cells established by Goldstein and Brown. Mahlavu cells, a new human hepatoma cell line, are thought to be useful in investigating cholesterol metabolism in the liver.

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We examined the suppressive effects of porcine pancreatic elastase and magnesium on experimental atherosclerosis. Five groups of rabbits were studied for 4 months as follows: a control group, two groups on a 1% cholesterol diet with and without porcine pancreatic elastase (Eisai Co. Ltd., 5mg i. m./kg B. W./day) and two groups on a 1% cholesterol diet containing an additional 1% magnesium with and without elastase.
Rabbits fed the cholesterol diet without elastase and/or magnesium showed significantly higher levels of cholesterol, triglycerides and calcium in the aortic tissue and in the elastin fraction than did the control animals. In rabbits on the cholesterol diet with elastase and/or magnesium, these components were reduced in both the aortic tissue and the elastin fraction. This reduction was especially significant in the elastin fraction. The marked suppression of triglyceride accumulations in both the aortic tissue and the elastin fraction was found in elastase-treated rabbits rather than in magnesium-treated rabbits; whereas the considerable suppression of calcium deposits in aortic tissue was found in magnesium-treated rabbits rather than in elastase-treated rabbits. In the elastin fraction, however the suppression effect of magnesium on calcium deposition was similar to that of elastase. There were an increase in polarr amino acids and a decrease in cross-linking amino acids in the isolated elastin from the aortas of untreated rabbits on the cholesterol diet. However, these changes were suppressed by treatment with elastase and/or magnesium. Furthermore, combined treatment with elastase and magnesium was more effective in both suppressing the increase of triglycerides in the elastin fraction and the changes in elastin amino acids and restoring the elastin content in the aortic tissue.
These results suggest that magnesium and elastase might be useful agents to suppress atherosclerosis.

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To determine the most effective index for predicting coronary sclerosis, various lipoproteins and apoproteins were examined. The study subjects included the following four groups: (1) 395 males and 127 females who underwent physical examinations, (2) 49 males and 10 females who were diagnosed as old myocardial infarction confirmed by coronary arteriography, (3) 45 males and 15 females with effort angina, and (4) 49 males and 10 females with vasospastic angina. Our results can be summaried as follows.
1) Using a box-whisker plot indicated that the LDL-C/HDL-C ratio and the Apo-B/Apo-AI ratio adequately reflected the level of coronary sclerosis.
2) An ROC curve demonstrated that the Apo-B/Apo-AI ratio was most accurate in discriminating coronary heart diseases.
3) The study on the effects of background factors on the Apo-B/Apo-AI ratio which used LOWESS and Q-Q plots did not disclose any factors that would affect the ratio except obesity which tended to elevate it.

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