Kazuo Ishiwata

Validation of the Friedewald Equation for Evaluation of Plasma LDL-Cholesterol

In most clinical laboratories, low density lipoprotein (LDL) cholesterol is usually estimated indirectly with the Friedewald equation or directly with the N-geneous assay. We assessed LDL-cholesterol values obtained by both methods to find an appropriate fasting period and to assess the influence of the energy content of the last meal. Blood samples were taken from 28 healthy volunteers who had consumed a standard meal (107 g of carbohydrate, 658 kcal) followed by a fasting period of 12 and 18 h, or a high-energy meal (190 g of carbohydrate, 1011 kcal) with a fasting period of 12 h. Prolongation of the fasting period from 12 h to 18 h decreased glucose level, but did not decrease triacylglycerol, total cholesterol, or high density lipoprotein (HDL) cholesterol. LDL-cholesterol levels measured with the N-geneous assay did not change (94.0 ± 21.5 to 96.3 ± 19.1 mg/dl). LDL-cholesterol levels calculated with the Friedewald equation were also similar after fasting periods of 12 h (98.5 ± 21.4 mg/dl) and 18 h (99.7 ± 20.2 mg/dl). The high-energy meal did not change the level of LDL-cholesterol measured with the N-geneous assay (96.1 ± 21.2 mg/dl), or the glucose, triacylglycerol, total cholesterol, or HDL-cholesterol level, but LDL-cholesterol levels evaluated from the Friedewald equation (92.6 ± 20.3 mg/dl) became significantly lower. A fasting time longer than 12 h is not necessary to obtain reasonable blood lipid levels. The Friedewald equation gave higher LDL-cholesterol levels than N-geneous assay in young Japanese females who had eaten a low-energy meal, and lower values when they had eaten a high-energy meal. Thus, it may be necessary to pay attention to energy of nigh meal prior to blood withdrawal.

Apolipoprotein-E phenotype and basal activity of low-density lipoprotein receptor are independent of changes in plasma lipoprotein subfractions after cholesterol ingestion in japanese subjects

We investigated whether the apolipoprotein-E (apoE) phenotype and the basal activity of low-density lipoprotein (LDL) receptor, which were reported to be the major determinants for increase in plasma LDL levels by cholesterol ingestion, have the same role in Japanese subjects whose diet is low in fat and cholesterol. Cholesterol (750 mg/d) was added to the ordinary diet as a dried egg-yolk supplement for 4 wk to 110 subjects. Plasma levels of lipids, apolipoproteins, and cholesterol in lipoprotein subfractions were measured at the beginning and end of the test period. Phenotyping of apoE was determined by an isoelectric focusing-immunoblotting method, and LDL receptor activity in lymphocytes was determined by flow cytometry. Plasma levels of cholesterol in less-dense LDL (LDL(1)) and less-dense high-density lipoprotein (HDL(2)) were slightly but significantly increased, 3.4% and 4.1%, respectively, by cholesterol ingestion, but the increases were not statistically significant in any of E2, E3, and E4 groups. The distribution of the apoE phenotype was equivalent in all three LDL-cholesterol groups (no change, increase, and decrease by cholesterol ingestion). Plasma levels of LDL, LDL(1), and LDL(2) cholesterol were not significantly increased in the three groups of subjects with lymphocyte LDL-receptor activities (low, medium, and high). As with apoE phenotype, LDL-receptor activities were the same in all three LDL-cholesterol groups. In addition, there were no significant correlations between LDL-receptor activity and changes in plasma levels of lipids, apolipoproteins, and cholesterol in lipoprotein subfractions. Therefore, we concluded that cholesterol ingestion significantly increases plasma levels of less-dense LDL and HDL, but neither apoE phenotype nor basal LDL-receptor activity explain the variability in changes in plasma lipoprotein subfractions by cholesterol ingestion in Japanese subjects.

Protective effects of fermented rice vinegar sediment (Kurozu moromimatsu) in a diethylnitrosamine-induced hepatocellular carcinoma animal model

Low-dose acetylsalicylic acid has been widely used. We evaluated small bowel and gastric injuries during acetylsalicylic acid administration using video capsule endoscopy and gastroduodenal endoscopy. We also investigated blood flow using contrast-enhanced ultrasonography. Six healthy volunteers were enrolled in this preliminary study. The subjects were administered 100 mg of enteric-coated aspirin daily for 14 days. Video capsule endoscopy and gastroduodenal endoscopy were simultaneously performed before administration and on days 1, 3, 7 and 14. Contrast-enhanced ultrasonography was performed before administration and on day 2, and 8. Video capsule endoscopy after administration of low-dose acetylsalicylic acid revealed small bowel mucosal damages of petechiae and erythema in all cases, and denuded area in one case. The total number of lesions in the small bowel increased according to duration of low-dose acetylsalicylic acid administration. However, the total number of lesions in the stomach peaked on day 3. Contrast-enhanced ultrasonography showed that the time-intensity curve peak value and Areas under the curves after acetylsalicylic acid administration were reduced. We observed not only gastric mucosal injuries but also small intestinal injuries with short-term low-dose acetylsalicylic acid administration. Acetylsalicylic acid administration also caused a decrease in small intestinal blood flow. Contrast-enhanced ultrasonography is useful for evaluation blood flow in the small bowel mucosa.

Inducible nitric oxide synthase knockout mouse and low-density lipoprotein oxidation

We have presented experimental procedures that examine macrophage-mediated LDL oxidation using Hams F-10 medium. By comparing iNOS-/- and iNOS+/+ macrophages, an antioxidant effect for NO and a prooxidant effect for IFN-gamma were demonstrated. The methods outlined here should allow for the investigation on the mechanism of in vitro LDL oxidation and how the macrophage-mediated LDL oxidation process is affected by various factors, one of which was the effect of iNOS induction by IFN-gamma.