Vitamin B6 is necessary for normal membrane function and stability. Here we studied both the function and ultrastructure of aortic and arterial endothelial cells (ECs) in vitamin B6 deficient mice induced by vitamin B6 antagonists, 4-deoxypyridoxine⋅HCl (dPN⋅HCl), and isonicotinylhydrazide (INH). Mice were fed with normal laboratory chow and divided into three groups according to their drinking water. Mice in group I had distilled water and served as a control; group II had 0.1mg dPN HCl/mL H2O; and group III had 0.4mg INH/mL H2O. After 5 mo, plasma concentrations of B6 vitamers pyridoxal-5'-phos-phate (PLP) and pyridoxal (PL) were analyzed by HPLC. With the arachidonic acid (AA) as a precursor, prostacyclin (PGI2) production from ECs assayed by thin-layer chromatography (TLC) was used as an indicator of endothelial function. Aorta and arteriole from foot pad were removed, stained with osmium tetraoxide, and examined under transmission electron microscopy (TEM) to study the ultrastructure of ECs. The results showed that plasma con-centrations of PLP, PL, and total B6 were the lowest for mice fed with INH, followed by that with dPN⋅HCl, compared with that of control. PGI2 production was paralleled with the plasma vitamin B6 status, with the lowest level for INH, followed by the dPN-treated group. Abnormalities in the ultrastructure of ECs were found in both dPN⋅HCl and INH groups, in-cluding cells detached from underlying elastic tissue, with prominent pinocytotic vesicles and swelling and or indistinct cristae of mitochondria. These results suggest that vitamin B6 antagonists induce a deficient status that alters the function and the ultrastructure of ECs detrimental to vascular disease.
The aim of this work was to study intestinal absorption, using the whole intes-tine in vivo with 5-methyltetrahydrofolate (5MTHF), and the subsequent appearance of this compound in the bile, in control and in ethanol-fed rats. The ethanol-fed rats drank ethanol (5 to 30% vol/vol) in tap water for 5 wk. A consumption of 30% was maintained in this group for 20 additional weeks. The two groups of rats were cannulated at the beginning and at the end of the intestine. Three solutions containing 0.5, 1.0, and 2.5μM of cold 5MTHF and 14C-methyltetrahydrofolic acid (0.01μCi/mL) in each were perfused through-out the intestine at a flow rate of 4.5mL/min. The absorption of folate was calculated from the difference between concentrations at the beginning and at the end of the perfusion. A decrease in 5MTHF uptake was observed at the concentration of 1.0 μM (p<0.05); however, folate absorption was not significantly modified at 0.5 and 2.5 μM in the perfusate. Serum folate levels were significantly lower in the ethanol-fed rat group. This fact could be due to a lower intake of folate in the diet and/or to the effect of alcohol on the intestinal absorption. The bile duct was isolated and cannulated with a polyethylene cathether. No significant dif-ferences were noted in the biliary folates between the control and the ethanol-fed rats.
The present study was performed to clarify the effects of dietary oils on phys-iological and metabolic changes induced by a stress, using one-time or repetitive water-im-mersion of restrained rats (single or repetitive stress) as an experimental stress load. In rats fed any test diets containing 20% of the mixture of tripalmitin, tristearin, and corn oil (PSC), olive oil (OLI), safflower oil (SAF), and linseed oil (US) with repetitive stress loading, body weight gains and food intakes were generally reduced. The weights of the thymus and spleen also declined, but the adrenal weights were enhanced. Particularly, the increase in the adrenal weight of rats given the OLI diet was greater than of rats supplied with other diets. When the rats were loaded with the single or repetitive stress, the concentrations of urea, lipid peroxide, and corticosterone in the plasma were increased in rats fed any of di-etary oils. The rise of plasma corticosterone level was especially great in rats fed the OLI diet. The concentrations of total cholesterol (T-CHOL) and triglyceride (TG) in the plasma and liver generally tended to be higher in rats fed the OLI diet than in rats given the other diets with and without stress exposure. Plasma corticosterone concentration was correlated to the adrenal weight (r=0.87, p<0.05). This study showed that OLI especially enhanced the adrenal weight in rats exposed to the repetitive stress and further raised the increased secre-tion of adrenal corticosterone in rats loaded with the single or repetitive stress compared with the other oils. The mechanism explaining these actions of OLI was inferred to be re-lated to the levels of T-CHOL and TG in the plasma and liver generally enhanced by stress.
The effect of a voluntary running exercise on blood pressure and renin-an-giotensin system (RAS) Was studied in male spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). SHR and WKY Were assigned to either voluntary running exercise or sedentary control groups at 5 wk of age. The systolic blood pressure in the exercised group for both strains of rats was significantly lower than in the sedentary control group. The plasma renin activity (PRA) and plasma renin concentration (PRC) were significantly lower in voluntary running exercised SHR than in sedentary SHR, whereas the same exercise did not result in a lower PRA and PRC in WKY. These results suggested that the blood pressure lowering effect of voluntary running exercise is related to the suppres-sion of RAS in SHR.
Hyperhomocysteinemia in chronic alcoholics has been reported, but it re-mains unclear whether relatively low alcohol intake compared with the previous reports af-fects the plasma homocysteine level. To investigate this issue, we performed two studies, a population-based study and an alcohol withdrawal study. An analysis of plasma homocys-teine levels in a population of 2 3 6 healthy males showed no significant association between alcohol consumption and other tested parameters. In the withdrawal study, the subjects with a history of daily alcohol consumption (81.8±33.0g/d, mean±SD, 40-150g/d, range) abstained from alcohol for 4 wk. After withdrawal, the levels of serum γ-glutamyl transpeptidase, aspartate aminotransferase, triglycerides, and high-density lipoprotein cho-lesterol significantly decreased, but the plasma homocysteine level did not change. These re-sults suggest that alcohol intake, at least as far as the amount of beverages our study sub-jects consumed, has no effect on the plasma homocysteine level in healthy males.
The effects of nucleotide and nucleoside supplementation on the formation of tight junctions and the expression of microvilli, as indexes of morphological differentiation were studied by using a human colon adenocarcinoma cell line (Caco-2 cells). The forma-tion of tight junctions and the expression of microvilli were evaluated by measuring the transepithelial electrical resistance (TEER) and observing the cell surface under electron mi-croscopic analysis, respectively. To clarify the nutritional significance of human milk nu-cleotides, we used a nucleotide mixture (and a corresponding nucleoside mixture) with a composition similar to that found in human milk. Nucleotides had no effect on TEER, but nucleosides markedly promoted the increase of TEER. When alkaline phosphatase activity in the brush border membrane was enhanced by the addition of triiodothyronine (TIT), nu-cleotides also promoted the increase of TEER. Cytidine and CMP predominant in the mix-ture influenced the increase of TEER materially. Furthermore, an electron microphotograph of the cell surface showed that nucleosides contributed to the expression of microvilli. Thus the results presented in this study suggest that nucleotide and nucleoside supplementation may enhance the morphological differentiation of Caco-2 cells.
The effects of the low-molecular-weight fraction of Papain-hydrolyzed pork meat (LMF) on the plasma cholesterol level and the generation of atherosclerosis were studied in rabbits fed a cholesterol-enriched diet. In LMF-fed rabbits, the plasma and liver cholesterol concentrations were both significantly lower (p<O.Ol) than in rabbits fed untreated pork meat (PM). Similarly, the cholesterol concentrations of the chylomicron and VLDL fractions were significantly lower in LMF-fed rabbits than in rabbits fed PM. Deposition of lipid in transverse sections of the aortic arch was significantly less in rabbits fed LMF than in those fed PM. Electron microscopic studies revealed preventive effects against premature atherosclerotic lesions in the aorta of rabbits fed LMF. These results indicate that LMF has a hypocholesterolemic action and preventive effects against premature atherosclerosis.
The daily energy expenditure and physical activity index of institutionalized Japanese elderly women were measured. One hundred and thirteen Japanese elderly women (aged 79.5±7.0 y) who live in institutions for the elderly and receive meal services partici-pated voluntarily. A dietary survey, energy metabolic study, and time study were carried out over three consecutive days, and the basal metabolic rate (BMR) and energy expenditure by physical activity were measured. The intensity of daily physical activity was based on the physical activity index (PAT: total/basal energy expenditure), The mean BMR was 881±145 kcal/d (20.9±3.8 kcal/kg BW). The PAT in individuals ranged from 1.01 to 1.5 7, the mean value was 1.26±0.14, and 64% of the subjects examined showed a lower value than 1.3 of PAT. From these values, the mean total energy expenditure was calculated as 1, 112±231 kcal/d (26.2±5.2 kcal/kg BW).
We studied the effects of specific inhibitors of methanogenesis (2-bromo-ethane sulfonate, BES) and sulfate reduction (sodium molybdate) on volatile sulfur production in batch cultures of pig cecal bacteria. The volatile sulfur concentration in head-space gas was determined by flame-photometric detector gas chromatography. BES stimulated production of hydrogen sulfide (H2S) and methanethiol, and sodium molybdate completely inhibited the production of these volatile sulfur compounds. The results indicated that dissimilate sulfate reduction is mainly responsible for volatile sulfur production in the hindgut. Therefore the extracts of herbs, food colors, and aroma chemicals were tested for their inhibitory effects on H2S production by a dissimilatory sulfate-reducing bacteria, Desulfovibrio desulfuricans DSM642. H2S was measured by the chromatography of the headspace gas, using a flame photometric detector. Of 306 herbal extracts tested, 69 extracts from 38 herbs inhibited H2S production at 1.0mg/mL. Sisymbrium officinale (hedge mustard) was the most potent inhibitor. Six pigments inhibited H2S release. Erythrosine and rose Bengal showed inhibitory effects at 0.01mg/mL. Peppermint oil and 96 aroma chemicals were assayed for their effects on H2S release. Thirty-two aroma chemicals suppressed H2S production at 0.1mg/mL, and camphene, l-decanol, and 2-nonanone were effective at 0.01mg/mL.
Cacao is rich in polyphenols such as (-)-epicatechin, and a colored compo-nent of cacao (cacao-red) is polyphenol, which is an antioxidant. These properties stimu-lated an investigation of the effects of cacao liquor polyphenols (CLP) on low-density lipoprotein (LDL) oxidation. The 2, 2'-azobis(4-methoxy-2, 4-dimethylvaleronitrile) (AMVN-CH3O)-induced oxidizability of LDL was assessed by monitoring the absorbance at 234 nm. In vitro, 0.1-0.5mg/dL CLP prolonged the oxidation lag time of LDL in a dose-dependent manner. Compared with the controls, it was prolonged 1.7-fold in the presence of 0.1mg/dL CLP, 2.9-fold at 0.2mg/dL, 3.8-fold at 0.3mg/dL, 5.4-fold at 0.4mg/dL, and 6.4-fold at 0.5mg/dL. Furthermore, we enlisted 13 male volunteers to consume 3 5 g delipidated cocoa. Venous blood samples were taken before and at 2 h and 4 h after consuming the cocoa. The oxidation lag time of LDL before cocoa ingestion was 59.0±6.3 min, but it was prolonged at 2 h after cocoa (68.3±6.0 min); before returning to the initial lag time (61.7±5.7min) before consumption. Thus we have shown that cocoa inhibited LDL oxidation both in vitro and ex vivo.
Oxidative stress has been postulated to play important roles in the pathogenesis of various diseases such as atherosclerosis in hyperlipidemic subjects. Although the possible role of oxidation of low-density lipoprotein (LDL) in the etiology of atherosclerosis has been studied extensively, the turnover of endogenous antioxidants, which is an important protection system against oxidative stress, remains to be elucidated. The aim of our study was to determine the change of the turnover of endogenous antioxidants such as glutathione and ascorbic acid in case of hyperlipidemia, using Japanese white rabbits (JW) and Watanabe heritable hyperlipidemic rabbits (WHHL). The levels of total glutathione and low molecular weight thiols in the liver, kidney, and other organs in both strains of rabbits were similar. However, a kinetic analysis using L-buthionine-(S, R)-sulfoximine revealed that the rate of glutathione turnover in the liver and kidney of WHHL was about 50% lower than that of JW Furthermore, intravenously administered ascorbic acid disappeared more slowly in WHHL than in JW These results indicate that the turnovers of both glutathione and ascorbic acid in WHHL are depressed in comparison with that in JW. These changes would be closely related to the increased oxidizability of lipids in the circulation of hyperlipidemic subjects.
Cottonseed kernels are rich in protein, but they have not been effectively utilized as a foodstuff because of the occurrence of glands that secrete gossypol, a toxic yellow pigment. Glandless cottonseeds (GLCS) are now available, and their kernels or flour are sold as a foodstuff. For this reason, a GLCS-tempe was prepared after the pattern of a traditional food called “Tempe” in Indonesia (fermented with Rhizopus oligosporus), and any gossypol remaining in GLCS proved to be lost in the process. Corn has not yet been used for tempe because of its difficulty to dehull; nevertheless, corn tempe was satisfactorily made from corn grits. Although GLCS-tempe was good, it smelled slightly unique just at swallowing. The preference for GLCS-tempe was correlated to the smell and taste. A combination of GLCS and defatted soybeans or corn at ratio of 1:1 led to many good effects on GLCS-tempe; e.g., favorable improvement in smell, taste, amino acid score, nutrient balance, and decrease of oligosaccharides related to the flatulence of the GLCS-tempe. Thus GLCS-tempe containing defatted soybeans or corn half of what can be expected to serve as a nutritious tasty food.