1. The effects of edible oyster mushroom Pleurotus ostreatus on plasma and liver lipid profiles and on the plasma total anti-oxidant status were estimated in hyper- and normocholesterolaemic Long Evans rats. 2. The feeding of 5% powder of the fruiting bodies of P. ostreatus mushrooms to hypercholesterolaemic rats reduced their plasma total cholesterol by approximately 28%, low-density lipoprotein-cholesterol by approximately 55%, triglyceride by approximately 34%, non-esterified fatty acid by approximately 30% and total liver cholesterol levels by > 34%, with a concurrent increase in plasma high-density lipoprotein-cholesterol concentration of > 21%. However, these effects were not observed in mushroom-fed normocholesterolaemic rats. 3. Mushroom feeding significantly increased plasma fatty acid unsaturation in both normo- and hypercholesterolaemic rats. 4. Plasma total anti-oxidant status, as estimated by the oxidation of 2,2'-azino-bis-[3-ethylbenz-thiazoline-6-sulphonic-acid], was significantly decreased in mushroom-fed hypercholesterolaemic rats, concomitant with a decrease in plasma total cholesterol. 5. The present study suggests that 5% P. ostreatus supplementation provides health benefits, at least partially, by acting on the atherogenic lipid profile in the hypercholesterolaemic condition.

Dutch-belted rabbits fed a 2% cholesterol diet for 8 weeks developed atherosclerotic lesions that covered 37.2% +/- 3.5% of the aortic luminal surface. In samples of aortic arch, accumulation of cholesterol and triglyceride was also observed. Oral administration of nicardipine or nifedipine at dosages of 40 mg/kg twice daily for 8 weeks reduced plaque area by 49.2% and 58.7%, respectively. Nicardipine and nifedipine reduced cholesterol accumulation in the aortic arch by 74.5% and 69%, respectively. Triglyceride accumulation was totally abolished. Neither drug significantly altered cholesterol concentration of plasma low density lipoprotein or high density lipoprotein, although nicardipine produced a 42% reduction in cholesterol concentration of the d less than 1.006 g/ml fraction. The above results suggest potential therapeutic utility of nicardipine in atherosclerosis.

The cytosol fraction of human platelets did not convert prostaglandin (PG) H 2 to PGD 2 . However, a homogenate of human megakaryoblastic CMK cells (precursor cells of platelets) produced PGD 2 from PGH 2 . The PGD synthase activity was localized in the cytosol of CMK cells, and absolutely required glutathione. The catalytic properties and Western and Northern blottings indicated that the enzyme was PGD synthase of the hematopoietic type rather than the lipocalin type. When CMK cells were differentiated to megakaryocytes with phorbol ester along with induction of cyclooxygenase-1, the PGD synthase activity increased about 2-fold for 2 days and then decreased. In another human megakaryoblastic cell line, Dami, the PGD synthase increased about 10-fold by the addition of phorbol ester. Thus, the PGD synthase, which was undetectable in platelets, appeared during differentiation of megakaryoblasts to megakaryocytes.

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