Effects of ML-236b (compactin) on sterol synthesis and low density lipoprotein receptor activities in fibroblasts of patients with homozygous familial hypercholesterolemia.

We studied biochemical genetics of low density lipoprotein (LDL) receptor mutations in fibroblasts from six homozygous and five heterozygous patients with familial hypercholesterolemia (FH). Three of six homozygotes are receptor-negative type and the other three homozygotes are receptor-defective type. In the cells from three receptor-negative homozygotes, the receptor binding, internalization, and degradation of (125)I-LDL were 0.5+/-0.3 ng/mg protein (mean+/-SEM), 14+/-8 and 8+/-6 ng/mg protein per 6 h (four normal cells; 44+/-3, 386+/-32, and 1,335+/-214 ng/mg protein per 6 h), respectively. In the cells from three receptor-defective homozygotes, the receptor binding, internalization, and degradation of (125)I-LDL were 6+/-2, 29+/-8, and 90+/-32 ng/mg protein per 6 h, respectively. In these six homozygotes, two pairs of siblings are included. Two siblings in the same family were classified as receptor-negative and two siblings in another family were classified as receptor-defective. The receptor-negative phenotypes and the receptor-defective phenotypes bred true in individual families. The cells from five heterozygotes showed approximately 46% of the normal activities of receptor.ML-236B, competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase), completely inhibited the incorporation of [(14)C]acetate into digitonin-precipitable sterols in fibroblasts from normal subjects and heterozygous and homozygous patients with FH with the concentration of 0.5 mug/ml. However, at 0.05 mug/ml of ML-236B sterol synthesis in fibroblasts from homozygotes was not completely suppressed in contrast to normal and heterozygous cells. Moreover, after preincubation with 0.05 mug/ml of ML-236B for 24 h in medium containing lipoproteins, sterol synthesis in the cells from receptor-negative homozygote showed 75% of the initial activity compared with that of 25% without preincubation. In the cells from a normal subject and a heterozygote, sterol synthesis was inhibited even after preincubation. These results suggest that (a) the inhibitory effect of ML-236B is overcome in homozygote cells by their high intracellular levels of HMG-CoA reductase and (b) that a higher dose of ML-236B may be required to lower serum cholesterol levels in FH homozygotes than in heterozygotes.

Serum lipids and coronary heart disease in heterozygous familial hypercholesterolemia in the Hokuriku District of Japan.

The serum cholesterol and triglyceride levels and the incidence of ischemic heart disease were studied in 122 (55 men and 67 women) consecutive heterozygous familial hypercholesterolemic patients in the Hokuriku district of Japan. (1) The mean +/-SD of serum cholesterol level was 354.0 +/- 71.0 mg/100 ml, which was lower than those of the Western countries by about 60--70 mg/100 ml. (2) The mean +/-SD of serum triglyceride level was 116.5 +/- 54.0 mg/100 ml. (3) The average serum cholesterol values in the 20--50-year-old group showed no differences from those of the Western countries. However, in the above 50 years of age group the serum cholesterol levels were much lower than those in the United States. (4) The occurrence of ischemic heart disease in 83 heterozygous familial hypercholesterolemic patients was 43.3%. The incidence of myocardial infarction was 20.5%. Thus, familial hypercholesterolemia is as highly atherogenic as that of the Western countries even in Japan where the low incidence of coronary heart disease in the general population has been attributed to the low level of serum cholesterol.

Serum lipids, lipoprotein lipids and coronary heart disease in patients with xanthelasma palpebrarum.

Serum lipids and lipoprotein lipids were studied in 53 patients (21 males and 32 females) with xanthelasma palpebrarum and 40 age-matched normal controls (20 males and 20 females). Patients were subdivided into patients with normolipidemia, hyperlipidemia or familial hypercholesterolemia (FH). In both male and female patients with hyperlipidemia or FH, the serum cholesterol (Chol) levels were significantly higher than in normal controls. In both male and female patients with normolipidemia or hyperlipidemia, the VLDL-Chol levels were significantly higher than in normal controls. Male patients with FH showed significantly higher levels of VLDL-Chol than normal controls. Both male and female patients with normolipidemia, hyperlipidemia or FH showed significantly higher levels of LDL-Chol, lower HDL-Chol levels and lower HDL-Chol/LDL-Chol ratios than normal controls. In both male and female patients with hyperlipidemia and in male patients with FH, the serum triglyceride (TG) levels were significantly higher than in normal controls. Both male and female hyperlipidemic patients showed significantly higher levels of VLDL-TG than normal controls. In male patients with FH, the VLDL-TG levels were significantly above the control levels. In male patients with normolipidermia, the LDL-TG levels were significantly higher than in normal controls. In both male and female patients with hyperlipidemia or FH, the LDL-TG levels were significantly higher than in normal controls. The HDL-TG levels in patients with normolipidemia (males) or FH (females) were significantly lower than in normal controls. The prevalence of coronary heart disease in patients with normolipidemia, hyperlipidemia or FH was 29.4%, 24.0% and 45.4%, respectively.

Studies on the synthesis of chemotherapeutics. 10. Synthesis and antitumor activity of N-acyl- and N-(alkoxycarbonyl)-5-fluorouracil derivatives.

A number of N-acyl and N-(alkoxycarbonyl)-5-fluorouracil derivatives possessing, for example, benzoyl, o-toluyl, acetyl, propionyl, heptanoyl, ethoxycarbonyl, phenoxycarbonyl, and benzyloxycarbonyl groups as N1 and/or N3 substituents were synthesized, and their antitumor activities were evaluated. The synthesis was achieved by a direct and two-step acylation of 5-fluorouracil and by selective N1-deacetylation of N1-acetyl-N3-substituted-5-fluorouracil under appropriate reaction conditions. Several N3-benzoyl- and N3-o-toluyl-5-fluorouracil derivates and showed significant activity against experimental tumor, and N1-acetyl-N3-o-toluyl-5-fluorouracil was found to be most promising among them. Further investigation revealed 12 to retain higher activity toward various tumors, with lower toxicity and good blood level, than either 1 or FT-207, even for oral administration.

[A case of lung cancer with hypercalcemia and renal failure responsive to pamidronate].

A 46-year-old man was diagnosed as Stage IV lung cancer with neck lymph node and bilateral adrenal metastases. He was treated with seven courses of combined chemotherapy (CDDP + etoposide), until he showed extreme hypercalcemia and acute renal failure. The bisphosphonate, pamidronate with elcatonin and prednisolone dramatically lowered his serum calcium level and normalized his renal function. This is a representative case of humoral hypercalcemia of malignancy whose serum calcium could be safely and effectively controlled with pamidronate.