Among the series of metabolic analogs of the eccentric cleavage pathway of β-carotene with different side chain lengths, retinoic acid was shown to have exceedingly higher molecular flexibility to undergo photoisomerization into the geometrical isomers under white fluorescent light. When irradiated with white fluorescent lamps (1, 200lx), the velocity of photoisomerization of all-trans-retinoic acid (8.4×10-⁷mol/L⋅min) was exceedingly higher than those of the other analogs: ionylideneacetic acid (4×10-⁸ mol/L⋅min), ionylidenecrotonic acid (3.0×10-⁷ mol/L⋅min), all-trans-β-apo-14'-carotenoic acid (1.7×10-⁷ mol/L⋅min), all-trans-β-apo-12'-carotenoic acid (1.3×10-⁷ mol/L⋅min), and all-traps-l-apo-8'-carotenoic acid (0.1×10-⁷ mol/L⋅min). β-Carotene did not un-dergo photoisomerization under the experimental conditions. The mo-lecular flexibility of retinoic acid is assumed to be an important basis of the mechanism of action of retinoic acid.

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We previously demonstrated that the large intestine com-pensated for decreased calcium (Ca) absorption caused by renal failure in rats fed a highly fermentable dietary fiber. In this study, we examined whether the large intestine compensated for insufficient Ca absorption in the rat small intestine without ingestion of a fermentable dietary fiber. Rats were fed one of four test diets containing either insoluble (carbonate) or soluble (gluconate, lactate, or citrate) Ca sources. The dietary Ca level was 2.0g/kg, which is lower than the minimum requirement for rats (3.0g/kg), to conduct the present study under a condition in which rats can maximally absorb Ca. To prevent Ca absorption in the small intestine, we replaced a primary phosphate (KH₂PO₄) with secondary phosphates (K₂HPO₄ and Na₂HPO₄) in diets. The apparent Ca absorption in the small intestine was estimated by adding chromic oxide (Cr₂O₃) as an insoluble and an unabsorbed marker to test diets and by measuring the ratio of Ca:Cr in the cecal content. The apparent Ca absorption in the whole intestine was estimated by the intake and fecal excretion of Ca. The apparent Ca absorption in the small intestine was significantly lower from the Ca carbonate diet than from the Ca gluconate, lactate, or citrate diets. The apparent Ca absorption in the whole intestine was not significantly different among the four groups, and the values were similar to the absorption rates in the small intestines of rats fed diets containing soluble Ca sources. These results show the following: (a) In rats fed 0.2% Ca diets containing soluble Ca salts, Ca is mostly absorbed in the small intestine, even in secondary phosphate intakes; (b) In contrast, in rats fed a 0.2% Ca diet containing an insoluble Ca salt (carbonate), Ca is not sufficiently absorbed in the small intestine. However, the large intestine compensates for the small intestinal Ca absorption decreased by dietary secondary phosphates.

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The effects of 1% arachidonic acid ethyl ester (AA) ad-ministration on the liver prostanoid metabolites and on serum and liver lipids in 3g/kg ethanol-administered rats fed 10% lard or corn oil were studied. The rats were divided into 6 groups: lard-sucrose (Lard-Suc); lard-ethanol without AA (Lard-Et); lard-ethanol with AA (Lard-EtAA); corn oil-sucrose (Corn-Suc); corn oil-ethanol without AA (Corn-Et); and corn oil-ethanol with AA (Corn-EtAA). Liver triglyceride increased in Corn-EtAA compared with Corn-Et. Arachidonic acid (20:4n-6) levels in liver phospholipid were significantly decreased in Corn-Et, but elevated in Lard-Et. The levels of 20:4n-6 were significantly increased with AA administration in both ethanol groups. Liver 6-keto-prostaglandin F1α (6-keto-PGF1α) in Corn-Suc (24.7±5.1 pg/mg protein) was markedly higher than in Lard-Suc (4.5±1.2pg/mg protein), and the 6-keto-PGF1α lowered significantly with the addition of ethanol (9.3±0.9pg/mg protein), but it increased with AA administration (21.6±4.9pg/mg protein). In Lard-EtAA, a significant increase in 6-keto-PGF1α was observed compared with Lard-Suc. The liver leukotriene B₄ (LTB₄) level in Lard-Suc was significantly lower than that of Corn-Suc. In the corn oil group, ethanol feeding was associated with a significant increase in liver LTB₄. AA administration to Corn-Et suppressed the elevated LTB₄. Serum thiobarbituric acid-reactive substance (TBARS) concentrations in the corn oil group were higher than in the lard group, and these concentrations were not altered by AA administration. From these results, we concluded that the administration of AA in rats treated with ethanol increased 20:4n-6 in liver phospholipid and liver PGI₂ levels, irrespective of dietary fat, and may protect against alcoholic liver injury. AA with a diet rich in linoleic acid (18:2_n-6), however, may increase fat in the alcoholic liver.

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Because of an increase in the number of elderly and the problems of nutrition associated with them, we considered it of interest to study the eating habits of 352 elderly persons (134 males and 218 females) 65 to 95 years of age in an urban area in the north of Spain (Oviedo). The purpose of this study was specifically to describe the differences in the eating habits of elderly institutionalized persons and those resident at home and to detect the nutritional status of 161 subjects living in institutions and 191 living at home. The weight, height, body mass index (BMI), and triceps skinfold (PTP) of each were recorded. To determine the eating habits, a questionnaire measuring the frequency of food consumption was distributed to the subjects. The mean age of the institutionalized elderly was greater than those living independently. The mean values of BMI indicated overweight in all cases, with values around those of obesity in independent females (BMI=29.97). The value of PTP was found to be within normal limits, but a greater percentage of institutionalized subjects showed PTP values of less than P10 (males, 10.2%; females, 11%). Food habits showed that the consumption of fish and margarine/oil was greater in institutionalized subjects of both sexes. Independent males consumed more vegetables; females consumed more milk and greens. Milk, vegetables, fruit, and fish were the food groups with consumption frequencies less than those recommended. A greater percentage of noncompliance was seen among the institutionalized elderly.

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The effects of dietary catechins and α-tocopherol on inflammatory bowel disease in rats were examined. Male 9-week-old rats were intracolonically administrated trinitrobenzene sulfonic acid (TNBS) and fed the experimental diets containing 0.05% catechin and 0.025% α-tocopherol for 1 week, then dissected. The extent of colitis-induced TNBS was assessed macroscopically. The supplementation of catechins and α-tocopherol significantly decreased colonic damage compared with the group fed the basal diet (the disease control). In particular, catechin feeding completely inhibited the development of colon adhesions. Colonic myeloperoxidase (MPO) activity, which is a marker of neutrophil infiltration into the colonic mucosa, was lower in the groups that had been given catechins and α-tocopherol. The levels of thiobarbituric acid reactive substances in colon was highest in the disease control group; however, the differences among the groups were not significant. Plasma alkaline phosphatase activity was maintained at normal levels in the rats supplemented with catechins and α-tocopherol. These results suggest that catechins and α-tocopherol have anti-inflammatory effects on TNBS-induced rat colitis.

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The purpose of this study was to investigate the effect of vitamin E on oxidative stress in the skeletal muscle of glucocorticoid-treated rats. Male Sprague-Dawley rats (5 weeks of age) were fed a basal diet or a diet supplemented with vitamin E (5, 000 mg DL-α-tocopheryl acetate/kg diet) for 10 d. The rats of both diet groups received subcutaneous injections of corticosterone (CTC) (0, 25, and 100mg/kg body weight/d) during the final 4d. Weights of the extensor digitorum longus and gastrocnemius (CAST) muscles were dose-dependently reduced by CTC. However, the muscle weight losses in rats fed the vitamin E diet were smaller than those in rats fed the basal diet. Protein carbonyl content in the GAST muscle, which was determined as an index of oxidatively modified protein, was increased by 100mg of CTC, and the increment was significantly (p<0.01) reduced by vitamin E supplement. Hypergly-cemia was induced by 100mg of CTC, but it was not affected by vitamin E. Lipid peroxide (TBARS) in plasma and in GAST muscle was elevated by 100mg of CTC, and vitamin E significantly (p<0.001) suppressed the formation of TBARS in the muscle. The change in TBARS paralleled that in protein carbonyl. These results show that CTC leads to oxidative stress in rat skeletal muscles and that vitamin E has roles in reducing the oxidative stress which causes muscle atrophy.

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The transitory laxative threshold of a partially digestible disaccharide, trehalose, and an undigestible disaccharide, lactulose, was estimated by the dose-response relation between the test substance and the prevalence of diarrhea in 20 healthy female subjects. The subjects ingested several indicated amounts of trehalose or lactulose once daily 2 to 3 h after a meal. The intake of the test substance was stopped at the dose level that caused diarrhea or when the dose reached the maximal level. A record of physical conditions, gastrointestinal symptoms, and fecal conditions was made by all subjects before and after each ingestion of the test substance. Half the subjects experienced no diarrhea even with the ingestion of the maximal dose level (60 g) of trehalose in this study, and the ingestion of up to 40 g of lactulose caused diarrhea in 75% of all subjects. Abdominal symptoms such as flatus, distension, and borborygmus appeared at high prevalence with lactulose and trehalose ingestion, and the effect of lactulose was significantly stronger than that of trehalose at the same dose level (p<0.05). The quantity of trehalose and lactulose that induced diarrhea differed greatly from person to person. The transitory laxative threshold was estimated as 0.65g/kg body weight for trehalose and 0.26g/kg body weight for lactulose by using the regression equation between the dose levels of the test substances and the cumulative incidence of diarrhea. These results suggest that it would be quite acceptable to administer trehalose up to 33 g and lactulose up to 13 g in a person weighing 50 kg.

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The effects of thyroxine (T₄) and triiodothyronine (T₃) on growth, muscle protein degradation, and proteases activities in cultured chick muscle cells were studied. The cells were treated with a physiological level of T₄ (60ng/mL) or T₃ (12ng/mL) for 6d. Calpain, cathepsins, and proteasome activities and N^τ-methylhistidine release were measured as indexes of myofibrillar protein breakdown. Creatine kinase activity was also measured as an index of myotube formation. Calpain activity was increased by T₄ and T₃. Cathepsin D and proteasome activities and N^τ-methylhistidine release were increased by T₃, but not by T₄. Neither were cathepsin B and B+L activities affected by T₃ or T₄. Creatine kinase activity was increased by T₄ and T₃. The results suggest that myotube formation is accelerated by T₄ and T₃, whereas myofibrillar protein degradation is accelerated by T₃, but not by T₄.

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Abnormal phospholipid metabolism may play an important role in the progression of atherosclerosis in renal failure. We analyzed plasma phospholipid and lysophospholipid contents and fatty acid composition in the phospholipids of 18 patients with renal failure on hemodialysis (HD) and compared the levels with those of healthy controls. HD patients had a notably higher molar ratio of the plasma lyso-phosphatidylcholine (lysoPC)/phosphatidylcholine (PC) distributed from 0.072 to 0.207, and the control group showed a ratio lower than 0.150. Plasma phosphatidylethanolamine (PE) concentration significantly increased in HD patients compared with control subjects. A much higher level of plasma lysophosphatidic acid (lysoPA) (1.41±0.16nmol/mL) was observed in HD patients compared with controls (0.54±0.08 nmol/mL). A strong correlation was found between plasma lysoPA and lysoPC concentrations (r=0.609, p<0.01) in HD patients. Serum inorganic phosphate (P) concentration was associated with the abnormal plasma lysoPC/PC, PE, and lysoPA levels in HD patients. Important decreases in eicosapentaenoic acid (EPA) of plasma PC and of dietary intake were observed in HD patients. Plasma thiobarbituric acid reactive substance (TBARS) concentration was negatively correlated with the amount of vitamin E intake in both subjects. These findings demonstrated the specific characteristics of the abnormal phospholipid metabolism in HD patients. The cause and consequences of elevated lysoPC/PC molar ratio and lysoPA in the plasma of HD patients remain to be established.

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We examined the physical constitution, serum lipids, fasting serum insulin (IRI), food intake, and physical activity in 1, 330 children in three age groups (6-7, 9-10, and 12-13) in Nagao village for the period 1994-1996. Serum total cholesterol (TC) and high-density lipoprotein-cholesterol (HDL-C) levels were positively correlated, and HDL-C and TG were negatively correlated in all age groups. IRI was significantly higher among the elder children, and it was also higher in girls than in boys. IRI was positively correlated with the body mass index (BMI) and triceps skinfold thickness in ages 9-10 and 12-13, but no significant correlation was noted with waist/hip ratio (W/H ratio). In ages 12-13, IRI was positively correlated with TC and TG and negatively correlated with HDL-C. In high-IRI children (above 11.4μU/mL) ages 12-13, the high-fat diet (fat-energy ratio above 30%) and low physical activity children (physical activity score below 10 points) were more frequent, and the mean levels of triceps skinfold were higher. The positive correlation between TC and HDL-C was not significant among high-IRI children. We concluded that a high-fat diet, low physical activity, and body fat accumulation influence the IRI level, which is closely related to serum lipid levels.

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We investigated the ameliorating effects of the three groups of water-soluble polysaccharides, a mixture of crude polysaccharides (FA), acidic polysaccharide fractions (FA-A), and neutral polysaccharide fractions (FA-N), obtained from the hot water extracts of the fruit bodies of Auricularia auricula-judae Quel. in genetically diabetic KK-A^y mice from 6 to 11 weeks of age. Male mice were divided into five dietary groups: 1) control group, given a basal diet; 2) FA group, given an FA diet (15g FA/kg diet); 3) FA-A group, given an FA-A diet (8g FA-A/kg diet); 4) low FA-N group, given a low FA-N diet (2g FA-N/kg diet); and 5) high FA-N group, given a high FA-N diet (8g FA-N/kg diet). Compared with the control diet, FA supplementation had significant effects in lowering fasting and nonfasting blood glucose, HbA_1c, urinary glucose, food intake, and water intake. FA administration also improved glucose tolerance to intraperitoneal glucose loading, but it did not affect the nonfasting insulin level. FA-N supplementation had dose-dependent effects in lowering fasting and nonfasting blood glucose, insulin, HbA_1c, urinary glucose, food intake, and water intake. However, the glucose tolerance was not ame-liorated by either the low or the high FA-N diet. FA-A administration showed no beneficial effects in KK-A^y mice.

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In the present study, we investigated antibody productions of IgA and other classes, such as IgE and IgGI, in mice as possible evidence of the protective effects of Spirulina toward food allergy and microbial infection. An increase of IgE antibody level in the serum was observed in the mice that were orally immunized with crude shrimp extract as an antigen (Ag group). The antibody level, however, was not further enhanced by treatment with Spirulina extract (SpHW). IgG1 antibody, on the other hand, which was increased by antigen administration, was further enhanced by Spirulina extract. It was noted that the IgA antibody level in the intestinal contents was significantly enhanced by treatment with Spirulina extract concurrently ingested with shrimp antigen, in comparison with that of the Ag group treated with shrimp antigen alone. An enhancement of IgA antibody production by Spirulina extract was also observed in culture supernatant of lymphoid cells, especially in the spleen and mesenteric lymph node from mice treated with Spirulina extract for 4 weeks before antigen stimulation. These results suggest that Spirulina may at least neither induce nor enhance allergic reaction such as food allergy dependent on an IgE antibody, and that when ingested both concurrently with antigen and before antigen stimulation, it may significantly enhance the IgA antibody level to protect against allergic reaction.

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To examine the relationship between serum vitamin C concentration and blood pressure level, a cross-sectional study was conducted. The subjects were 919 men and 1, 266 women aged 40 years and over in a Japanese provincial city, Shibata, Niigata Prefecture. The mean and standard deviation of systolic blood pressure (SBP) were 134.0±20.0 mmHg for men and 128.3±20.8 mmHg for women, and those of diastolic blood pressure (DBP) were 81.0±11.7 mmHg and 75.8±11.4 mmHg, respectively. The mean and standard deviation of serum vitamin C were 42.5±18.6 μmol/L for men and 56.8±16.5 μmol/L for women. SBP and DBP were both inversely correlated with serum vitamin C concentration. The means of SBP or DBP were calculated for quartiles of serum vitamin C, and the significant inverse relationship was observed in any sex and age group. The inverse association persisted after adjustment for possible confounders: body mass index, serum total cholesterol, alcohol consumption, smoking, physical activity, anti-hypertensive medication, and dietary intake of salt, calcium, and potassium. Serum vitamin C appeared to be inversely related with both SBP and DBP in this Japanese population, although further intervention and experimental studies were required to establish the cause-effect relationship.

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The effect of dietary L-lactic acid (LA) (0.5, 1, 0, or 2.5g/100g of diet) on the absorption of calcium in gastrectomized rats was evaluated for 28d. Calcium phosphate was used as a source of calcium. The apparent calcium absorption ratio and the calcium contents of the femur and tibia in gastrectomized rats fed the control diet were significantly less than those in sham-operated rats. In the gastrectomized rats, the apparent calcium absorption ratio and the calcium contents of bone in the rats fed the lower doses of LA diets (LA 0.5 or 1.0g/100g of diet) were not affected; however, the apparent calcium absorption ratio and the calcium contents of bone in the rats fed the highest doses of LA diet (LA 2.5g/100g of diet) were greater than those in gastrectomized rats fed the control diet. Dietary LA (2.5g/100g of diet) also enhanced the phosphorus absorption and bone phosphorus content in the gastrectomized rats. We speculated that the highest dose of dietary LA might be associated with the dissolving of a water-insoluble form of calcium salt in the diet, thereby facilitating the calcium absorption and resulting in increased bone calcium content in gastrectomized rats.

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Soybean flour was fermented with Aspergillus usamii to improve the availabilities of dietary zinc and iron through the degradation of phytate. Three kinds of experimental diets that differed in protein sources were prepared: one consisting of 40% regular soybean flour (RS diet), one consisting of 40% fermented soybean flour (FS diet), and one consisting of 20% regular soybean flour and 20% fermented soybean flour (RF diet). Zinc solubilities in the upper and the lower segments of the small intestine were higher in rats fed the FS diet than in rats fed the RS diet. The FS group showed higher solubility of iron in the lower small intestine than the RS group did. Zinc concentrations in the femur and plasma and iron concentrations in the liver and plasma were higher in the FS group than in the RS group. These results suggested that the fermentation of soybean flour improved the availabilities of dietary zinc and iron, which may be induced by increasing the solubilities of these minerals in the small intestine through the reduction of phytate content. Femoral and plasma zinc concentrations in the RF group were higher than in the RS group, but lower than in the FS group. No difference was noted in liver and plasma iron concentrations between the RF group and the FS group. Although phytase activity in FS degrades phytate in the RF diet, higher activity may be needed to degrade phytate completely.

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Powdered bovine marrow-free bone was completely solubilized with lactic and citric acids under reduced pressure. The resulting solution was lyophilized to obtain a stable powder form (total bone extract, TBE), and the calcium (Ca) absorbability of TBE from intestine was investigated in normal rats. Each animal perorally received 10mg of Ca in 1mL of distilled water as extrinsic ⁴⁵Ca-labeled TBE, intrinsic ⁴⁵Ca-labeled Ca lactate, or intrinsic ⁴⁵Ca-labeled Ca carbonate. The amount of radioactivity in plasma was measured periodically up to 34h after dosing, and pharmacokinetic parameters were calculated from the radioactivity in plasma. The time taken to reach the maximal ⁴⁵Ca level (Tmax) did not differ among the three groups. The area under the plasma ⁴⁵Ca level/time curve (AUC∞) and the radioactivity at Tmax (Cmax) values for the TBE group were significantly higher than those of the Ca carbonate group. Similar results were observed between the Ca lactate and the Ca carbonate groups. No significant difference was observed in the AUC∞ and the Cmax values between the TBE and the Ca lactate groups. Radioactivity in a femur 34h after dosing was highest in the Ca lactate group and lowest in the Ca carbonate group among the three groups. Both the TBE and the Ca lactate groups showed significant higher whole-body ⁴⁵Ca retention than the Ca carbonate group did, although no significant difference was found between the TBE and the Ca lactate groups. These findings indicate that the Ca absorbability of TBE is almost comparable with that of Ca lactate and higher than that of Ca carbonate. Therefore TBE would be useful as a Ca supplement with relatively high absorbability from intestine.

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