The α-tocopherol stereoisomers in biological specimens were investigated using high-performance liquid chromatography. All-rac-α-T oc acetate was separated into four peaks (peak area ratio: 4:2:1:1) by Chiralpak OP(-f-) HPLC. 2R-isomers constituted the first peak and 2S isomers were separated into three peaks (peak area ratio:2:1:1). 2-Ambo-α-T oc acetate was completely separated into RRR- and SRR-a-Toc acetate by this method. The present HPLC method was used for the separation of all-rac-α-Toc in blood and tissues of rat. The analytical recoveries of RRR- and SRR-a-Toc acetate added to blood and tissues were 90.5-98.2% for RRR-a-Toc and 93.7-100.5% for SRR-α-Toc. The distribution of α-Toc stereoisomers in the blood and tissues from rats administered all-rac-a-Toc acetate was investigated by HPLC. The concentrations of the 2R-isomers in the blood and tissues were markedly higher than the concentrations of the 2S isomers, and the levels of a-Toc stereoisomers showed marked differences between blood and tissues.

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A series of acid homologs with longer side chain length was synthesized and their biological activities to inhibit growth and to induce differentiation of human acute promyelocytic leukemia cell line HL-60 were analyzed. It was found that ethyl α-retinylidene propionate (E) shows interesting activity. This compound inhibited growth of HL-60 cells with almost the same potency of retinoic acid. However, unlike retinoic acid, the potency of this compound to induce differentiation of HL-60 cells into neutrophiles was almost negligible. Ethyl α-retinylidene propionate (E) is an unprecedented retinoid which inhibits growth of HL-60 cells without inducing cell differentiation. The Z isomer [ethyl α-retinylidene propionate (Z)] also showed similar unique effects on HL-60 cells. Interestingly, both of the E and Z isomers of α-retinylidene propionic acid showed only very weak activities to inhibit growth and to induce differentiation of HL-60 cells. It was suggested that ethyl α-retinylidene propionate acts on HL-60 cells in the intact form without suffering hydrolysis, and also that the ester group plays important role for the unique activity. Biological activities of retinylidene acetic acid (E and Z) which lacks methyl group at α-position of α-retinylidene propionic acid, on HL-60 cells were weaker than those of the isomers of α-retinylidene propionic acid. Esterification of the isomers of retinylidene acetic acid resulted in further decrease of biological activities. Biological activities of ethyl retinoate on HL-60 cells were also very weak. It was indicated that methyl group present at a-position of ethyl α-retinylidene propionate plays an important role for the unique biological activity. It was further indicated that the effect of esterification of carboxyl group of retinoids on the biological activity is not constant, but varies depending on the structure. Pretreatment of HL-60 cells with ethyl α-retinylidene propionate (E) apparently did not influence the process of induction of differentiation of HL-60 cells into neutrophiles by retinoic acid. It was further shown that ethyl α-retinylidene propionate (E) prolongs the time necessary for induction of differentiation of HL-60 cells by retinoic acid, but does not influence the level of final rate of differentiation.

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The relationships of cigarette smoking, exercise, and body mass index (BMI) to the serum levels of high-density lipoprotein (HDL) cholesterol, apolipoprotein AI (Apo AI), apolipoprotein All (Apo All), and % of HDL cholesterol to total cholesterol (%HDL-C) were assessed in 495 employees of a telephone company in Japan. They were subdivided into four groups by frequency of alcohol intake: nondrinkers (n=28), those who drank once per week (n=78), those who drank 2 to 5 times per week (n=245), and those who drank b to 7 times per week (n=144). Although univariate analysis before grouping showed a positive correla-tion between Apo All and BMI, multiple analysis examined in each group showed the positive relationship only in the nondrinking group. The relationship between BMI and Apo All would thus appear to depend on drinking habits.

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The milk fatty acid compositions of mothers fed on a fatfree or various fat diets, and the effects on growth and fatty acid compositions of their pups were studied. Even the milk of essential fatty acid-deficient mothers fed on a fat-free or hydrogenated fat diet contained about 3 and 1.7%, n-6 and n-3 fatty acids, respectively. In the plasma of the suckling pups, however, the proportions of n-6 and n-3 fatty acids rapidly increased to about 20 and 3-5%, respectively, at 1 week after birth. In particular, the PUFAs markedly increased in the liver PC and PE, and the high levels were maintained until weaning. Although the PUFA compositions of suckling pups were influenced with those of maternal diet, small amounts of n-6 and n-3 fatty acids were usually maintained in the plasma and liver. After weaning to the same diets (without PUFAs) as the mothers, however, the n-3 and n-6 fatty acids rapidly decreased and endogenous n-9 eicosatrienoic acid appeared. On the other hand, the growth during suckling was not significantly different among the litters of mothers fed on diets with or without n-3 or n-6 fatty acids. After the weaning, however, the growth was improved in the following order: corn oil, perilla oil>fish oil>fat-free, hydrogenated fat diet group. n-3 fatty acids appeared to be used partially as substitutes for n-6. However, the essentiality was not clear, as the n-3 fatty acids always coexisted with the n-6. Thus, it appeared that small amounts of n-3 and n-6 fatty acids in milk were supplied to the suckling animals regardless of maternal diet and supported growth.

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Effects of endogenous and exogenous polyunsaturated fatty acids (PUFA) on microsomal synthesis of docosahexaenoic acid (DHA) from eicosapentaenoic acid (EPA) in vitro were studied using rat livers. Liver microsomes prepared from three groups of rats which had been fed n-3/n-6 ratios of 0.01, 0.39, and 2.70, respectively, for 1 month, were incubated with [1-¹⁴C] EPA at 37°C for 30 min. There were no significant differences between the formations of docosapentaenoic acid (DPA) or DHA in the groups. Liver microsomes from rats fed a diet with an n-3/n-6 ratio of 2.70 for 3 weeks were then incubated with [ 1-¹⁴C] EPA in the presence of unlabeled DHA or arachidonic acid (AA). The additional DHA did not have any effect. However, a significant inhibition of DHA synthesis was observed by addition of AA (EPA/AA=5:2). These results suggest that the microsomal biosynthesis of DHA in rat liver is not susceptible to feedback inhibition.

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A method was introduced for the estimation of total diet-ary fiber (TDF) intake of a population using a menu-oriented question-naire and a menu-based calculation table. TDF intake correlated well with age in a population investigated, and in younger generations TDF consumption was very low (less than 11.5 g/day in teenagers). The similar results were obtained from the calculation using data of National Nutri-tion Survey (10.7 g/day). The foodstuffs they consumed were more processed and refined. This fact suggested that in younger generations a future resumption of their present eating habits might produce a serious lack of TDF intake in later years. To clarify the optimal level of TDF intake for the upper limit of recommended daily allowance (RDA) of an average Japanese, the following were measured and calculated. (I) Estimation of recent TDF intake (1990) and of 30 and 50 years ago (1955, 1935), based on TDF data of foodstuffs by the enzymatic-gravimetric method. (II) Measurement of the TDF of model duplicate meals and model composite diets for the average Japanese in 1985 using the same assay method. (III) Conversion of a recommendation of 20-35 g/day for American into RDA for Japanese considering energy consump-tion and lower fat intake. (IV) Re-estimation of the literature data on the adverse effects of DF on the human mineral balance considering the insufficient calcium intake of Japanese. The results indicated an RDA of 10-12g TDF/1, 000 kcal fit better for an average Japanese.

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The effects of transgalactosylated disaccharide (TD) intake on human fecal microflora and their metabolism were investigated in 12 Japanese males. TD is a mixture of sugars, galactosyl galactose, and galactosyl glucose, synthesized from lactose through the transgalactosyla-tion reaction of Streptococcus thermophilus β-galactosidase. Volunteers took 15 g of the test sugar daily for 6 days. The TD ingestion increased the number of bifidobacteria and lactobacilli, but decreased the number of Bacteroidaceae and Candida spp. in the feces. The ratio of bifidobacteria to total bacteria increased from 0.28 to 0.51. TD decreased the fecal concentrations of propionic acid, isobutyric acid, isovaleric acid, and valeric acid. This sugar also lowered the fecal pH, and the concentrations of fecal ammonia, p-cresol, and indole. Moreover, a positive correlation was found between the concentration of ammonia, and that of branched-chain fatty acids (isobutyric acid and isovaleric acid), p-cresol, and indole. All of these compounds are produced from amino acids through deamination by the intestinal bacteria. The depression of amino acid fermentation by intestinal bacteria may be involved in the reduction of fecal ammonia. These results suggest that a part of the trans-galactosylated disaccharides passes into the colon, inducing changes in the colonic microflora composition, hastening carbohydrate fermentation, and depressing amino acid fementation in the human gut.

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