摘要:

Consumption of eggs for a long period was shown to result in hypercholesterolemia and is generally restricted for this reason. In the present study we analyzed the effect of eggs consumption for 3 weeks on lipoprotein atherogenicity. Consumption of 2 eggs per day with the meals, for 3 weeks resulted in a minor elevation in plasma glucose and urea concentrations. Plasma cholesterol concentration increased by 11 % (p < 0.05) as a result of increased plasma low-density lipoprotein (LDL) cholesterol levels. Plasma triglycerides decreased by 13% (p < 0.01), but there were no significant alterations in plasma apolipoproteins A-I or B-100 concentrations. Plasma high-density lipoprotein (HDL) cholesterol decreased by 11 % (p < 0.05). There was a 13% reduction, though not significant, in the cholesterol efflux from J-774 A.l macrophages by HDL that was derived after eggs consumption in comparison to HDL that was obtained at baseline. The susceptibility of plasma [using 100 mMof 2,2’ azobis 2-amidinopropane (AAPH)] as well as that of LDL (using 10 µM of copper ions) to lipid peroxidation was increased by 42% and 34%, respectively, as measured by the thiobarbituric acid reactive substance (TBARS) assay (p < 0.01). Kinetic analysis of LDL oxidation by copper ions revealed a 37% reduction in the lag time required for the initiation of LDL oxidation after 3 weeks of eggs consumption. The total plasma fatty acids concentration increased from 2.2 ± 0.5 to 3.2 ± 0.6 mg/ml. The plasma antioxidants, vitamin E and carotenoids were not significantly affected by eggs consumption. We conclude that eggs consumption, in addition to its hypercholesterolemic effect, increases plasma and LDL oxidizability, a phenomenon which was shown to enhance the progression of atherosclerosis. These atherogenic properties may contribute to the accelerated atherosclerosis prevalent in populations with high cholesterol in

ISSN:0250-6807    

DOI:10.1159/000177964

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

In this study, glycoproteins and oligosaccharides with sialyl Lewis a, sialyl Lewis x, Lewis x, and Lewis y epitopes were isolated by ultracentrifugation and fast-protein liquid chromatography from human milk of mothers with term or preterm infants. The identification of these epitopes on whey proteins was achieved by monoclonal antibodies and lectins after Western blotting. Lactose-derived oligosaccharides were characterized by high-performance thin-layer chromatography and high-pH anion-exchange chromatography with pulsed amperometric detection. These carbohydrate epitopes which are potential ligands for selectins are not of cellular origin but appear in the soluble fraction of milk. Here, they are present as lactose-derived oligosaccharides (molecular weight 100 kD). Lewis antigens might represent another category of protective nonimmunological substances in human milk with the potential to influence inflammatory processes in human milk fed infants.

ISSN:0250-6807    

DOI:10.1159/000177965

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

The influence of docosahexaenoic acid (DHA) and sardine oil diets on the ultrastructure of jejunal absorptive cells was studied. Adult male Crj:CD-l (ICR) mice were fed a fat-free semi-synthetic diet supplemented with 5% (by weight) purified DHA ethyl ester, refined sardine oil, or palm oil. The mice received the DHA or palm oil diets for 7 days (groups 1 and 2) and the refined sardine oil or palm oil diets for 30 days (groups 3 and 4). There were significant ultrastructural changes in the jejunal absorptive cells between the mice fed on the palm oil diet and those receiving the DHA and sardine oil diets. The endoplasmic reticulum and Golgi apparatus of some jejunal absorptive cells in the mice fed on the palm oil diet for 7 and 30 days developed vacuolation on the upper site of the nucleus. In contrast, many granules, which appeared to be lip-id droplets, were observed in the endoplasmic reticulum and Golgi apparatus of the jejunal absorptive cells in the DHA and sardine oil diet groups. These results suggest that ultrastructural differences in the jejunal absorptive cells between mice in the omega-3 fatty acid and palm oil diet groups may be associated with the changes in lipid metabolism.

ISSN:0250-6807    

DOI:10.1159/000177966

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

The effect of dietary fats on the chemical composition and enzyme activities has been studied in intestinal brush border membranes (BBM) of rats. Animals were given commercial rat pellet diet (RP) or semisynthetic diet rich in either saturated [coconut oil (CCO)] or polyunsaturated [n-6, corn oil (CO) or n-3, fish oil (FO)] fat at the 10% level for 5 weeks. The membrane cholesterol/phospholipid ratio was augmented in CO- or RP-fed rats. There was an increase in level of saturated fatty acids in BBM from CCO- or FO-fed animals, n-3 polyunsaturated fatty acid content was raised in FO-fed rats, while the proportion of linoleic acid and arachidonic acid was enhanced in animals given a CO diet. Membrane fluidity was in the order of CCO < RP = CO < FO. The membrane hexose content was high (p < 0.05) in the CCO group. Hexosamines were elevated (p < 0.05) in CCO- or FO-fed rat brush borders. Membrane fucose was unaltered, while sialic acid content was elevated in CO- (p < 0.05) and FO- (p < 0.01) fed vs. CCO-fed rats. Lectin binding to brush borders corroborated these findings. The activities of alkaline phosphatase, sucrase and lactase were augmented (p < 0.001) in CCO-fed animals. Leucine-aminopeptidase and sucrase activities were depressed by FO feeding. The activities of PNP-β-glycosidases were the highest in FO-fed rats. These results indicate that dietary fat quality markedly affects microvillus membrane lipid composition, glycosylation and enzyme functions in rat intestine

ISSN:0250-6807    

DOI:10.1159/000177967

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

This study sought to determine the intestinal in vivo absorption of folic acid and methyltetrahydrofolate (MTHF) by jejunum surface at different times, after 20 weeks of 30% ethanol ingestion. The absorption results were compared with the data of control rats. In general after ethanol treatment jejunal folic acid absorption was higher than in control rats. When the folic acid concentrations in the perfusion medium were 0.5 µM an increase at later times in ethanol-fed rats was found. At 1 µM the folic acid absorption values were significantly higher at the earlier time. When the concentration assayed was 2.5 µM, significant modifications were only seen at 30 min. Results of MTHF absorption by jejunum of ethanol-fed rats were similar to absorption values of control rats. No significant differences between both groups were found. The results obtained in the present work suggested a different absorptive behavior of both substrates and a different effect of ethanol on folic acid and MTHF absorption in the jejun

ISSN:0250-6807    

DOI:10.1159/000177968

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

This study was designed to determine the intestinal in vivo absorption of folic acid and methyltetrahydrofolate (MTHF) by the caecum surface at different times after 20 weeks of 30% ethanol ingestion. The absorption results were compared to the data of control rats. Chow and fluid consumption and body weight were significantly lower in ethanol-fed rats. The absorption of folic acid and MTHF by the caecum surface (pmol/cm2) was generally decreased in ethanol-fed rats at all concentrations assayed with respect to control animals (except for absorption of 0.5 and 2.5 µM folic acid at 15-min intervals). The results obtained in the present work also suggest a different absorptive behaviour of folic acid and MTHF in the caecum under the influence of chronic alcohol ingestion

ISSN:0250-6807    

DOI:10.1159/000177969

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

The development of pig adipose tissues is influenced by several factors such as localisation and dietary fat. The neck and backfat subcutaneous adipose tissues consist of two layers with different chemical compositions, and it is not yet known whether such variations are due to differences in lipogenic enzyme activities or to other factors. The aim of the present study was to compare the lipogenic activities of tissues from different sites (Longissimus dorsi muscle, liver, subcutaneous backfat) and between the outer and inner backfat layers. The effects of dietary fat from two animal sources on the lipogenic activities and fatty acid composition of these tissues were also compared. 28 Large White × Pietrain cross-bred swine, averaging 75 (initial) to 108 kg (final) live weight, were allocated into 2 groups. They were fed diets with the same energy and lipid contents but provided either by goat’s milk or cow’s milk. The lipid content and fatty acid composition of the tissues were determined and the following lipogenic enzymes activities measured: acetyl-CoA carboxylase (CBX); glucose-6-phosphate dehydrogenase (G6PDH) and malic enzyme (ME). Both groups showed similar average daily gain, carcass composition and tissue lipid contents. Lipogenic activities were highest in backfat (p < 0.001), intermediate in Longissimus dorsi muscle and lowest in liver. The lipogenic activities in backfat tissue were greater (p < 0.001) in the inner than in the outer layer in both groups. Animals fed on goat’s milk exhibited greater (p < 0.05) CBX and ME activities in the backfat, and CBX (p < 0.05) activity in the Longissimus dorsi muscle. In backfat tissue of animals fed on goat’s milk, CBX, G6PDH (p < 0.01) and ME (p < 0.05) were greater in the inner than in the outer layer, whereas in animals fed on cow’s milk the inner backfat layer exhibited the slightly higher (p < 0.05) lipid content. Differences in CBX activity between the two dairy diets tended to be greater (p < 0.001) in the inner backfat than in the outer layer. This suggests that the inner layer might be more sensitive to dietary source fat. It is concluded that the layers of pig subcutaneous backfat should not be considered as a single entity, but rather as two separa

ISSN:0250-6807    

DOI:10.1159/000177970

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Selenium (Se) is vital for animals and humans, as it is an essential component of Se-dependent glutathione peroxidase (GPx), an enzyme that reduces peroxides and protects cells against the damaging effects of oxidation. Se has, however, been found in rat plasma even when the enzymatic activity of GPx is very low, supporting the hypothesis that Se is also bound to other proteic structures. The purpose of this work was partially to purify the selenium-containing proteins in plasma, without denaturation, by isoelectrofocusing. We observed two pH intervals in the plasma where Se-containing proteins concentrated upon focusing: the first, at pH 6.0 ± 0.2 and with GPx activity, and the second, between pH 4.6 and 5.4, with no enzymatic activity. We can infer therefore that other Se-containing proteins are present at a lower pH than 6, and in particular between 4.6 and 5.4

ISSN:0250-6807    

DOI:10.1159/000177971

出版商:S. Karger AG    

年代:1996

数据来源: Karger