桑蚕蛹的脂质营养组成

目的分析桑蚕蛹脂类营养组成,综合评价其营养价值。方法分别采用GC、TLC、HPLC法分析氯仿/甲醇萃取的蚕蛹脂质脂肪酸、生育酚、甾醇、磷脂含量及组成。结果蚕蛹的总脂质含量32.79%,蚕蛹油中最主要的脂肪酸有α-亚麻酸、油酸、棕榈酸、其次为亚油酸和硬脂酸。甾醇中胆固醇含量最高,其次为β-谷甾醇,分别占总甾醇的67.35%、19.21%。菜油甾醇、菜籽甾醇含量甚微。蚕蛹油中总生育酚含量为486mg/kg,其中α-,γ(+β)及δ-生育酚分别占总甾醇的44.85%、44.57%和10.85%.蚕蛹磷脂种类丰富,总磷脂水平为1.17mg/goil,其中磷酯酰胆碱含量最高(41.8%)。结论蚕蛹油含有丰富的功能因子,尤其富含α-亚麻酸、α-生育酚、β-谷甾醇及卵磷脂,是潜在的高营养价值的食用油。     

Liver X receptor modulators: Effects on lipid metabolism and potential use in the treatment of atherosclerosis

Liver X receptors (LXRs) are nuclear receptors that play a crucial role in regulating the expression of genes involved in lipid metabolism. Ligand activation of LXRs improves cholesterol homeostasis via multiple coordinated effects, and this function is likely to explain in part the protective effects of LXR activation on atherosclerosis reported in animal models. However, LXR activation may also induce undesirable side effects, such as lipogenesis and hypertriglyceridemia. This review discusses the potential to develop LXR modulators as therapeutic agents for atherosclerosis.     

Scavenger receptors as regulators of natural antibody responses and B cell activation in autoimmunity

Innate immune activation is crucial in defense against invading pathogens, including recognition by pattern recognition receptors, such as scavenger receptors. The scavenger receptor family was originally defined by their ability to bind oxidized LDL and thus the majority of research on this set of receptors has been done in association with cardiovascular disease. However, these receptors also bind an array of other modified self and foreign ligands and have for this reason the ability to regulate the immune response, including B cell activation. In this respect, increasing evidence suggests that these receptors are involved in autoimmunity and might provide a link between autoimmune disease and atherosclerosis. In this review, we will summarize how scavenger receptors can regulate activation of B cells both through their expression on this cell type but also by functions mediated by expression on cells interacting with B cells. Recent evidence of scavenger receptor function reveals how the transition from natural and polyreactive antibody responses towards potentially pathogenic B cell activation occurs. This translates to a new role for scavenger receptors in atherosclerosis and autoimmune disease, such as systemic lupus erythematosus.     

N-(4-iodophenyl)-N'-(2-chloroethyl)urea as a microtubule disrupter: in vitro and in vivo profiling of antitumoral activity on CT-26 murine colon carcinoma cell line cultured and grafted to mice

The antitumoral profile of the microtubule disrupter N-(4-iodophenyl)-N'-(2-chloroethyl)urea (ICEU) was characterised in vitro and in vivo using the CT-26 colon carcinoma cell line, on the basis of the drug uptake by the cells, the modifications of cell cycle, and beta-tubulin and lipid membrane profiles. N-(4-iodophenyl)-N'-(2-chloroethyl)urea exhibited a rapid and dose-dependent uptake by CT-26 cells suggesting its passive diffusion through the membranes. Intraperitoneally injected ICEU biodistributed into the grafted CT-26 tumour, resulting thus in a significant tumour growth inhibition (TGI). N-(4-iodophenyl)-N'-(2-chloroethyl)urea was also observed to accumulate within colon tissue. Tumour growth inhibition was associated with a slight increase in the number of G2 tetraploid tumour cells in vivo, whereas G2 blockage was more obvious in vitro. The phenotype of beta-tubulin alkylation that was clearly demonstrated in vitro was undetectable in vivo. Nuclear magnetic resonance analysis showed that cells blocked in G2 phase underwent apoptosis, as confirmed by an increase in the methylene group resonance of mobile lipids, parallel to sub-G1 accumulation of the cells. In vivo, a decrease of the signals of both the phospholipid precursors and the products of membrane degradation occurred concomitantly with TGI. This multi-analysis established, at least partly, the ICEU activity profile, in vitro and in vivo, providing additional data in favour of ICEU as a tubulin-interacting drug accumulating within the intestinal tract. This may provide a starting point for researches for future efficacious tubulin-interacting drugs for the treatment of colorectal cancers.     

Effects of antipsychotic treatment on membrane phospholipid metabolism in schizophrenia

Summary. Several studies have shown an increased membrane phospholipid turnover in brain and blood cells of schizophrenic patients. However the specificity of these findings for schizophrenia and the effects of longterm antipsychotic treatment had yet to be demonstrated. In the present study we measured the concentrations of phospholipids in platelet membranes from 67 neuroleptic-free schizophrenic patients compared to both healthy and psychiatric controls, followed by repeated measurements during a 6 months antipsychotic treatment period. At baseline, levels of the main phospholipid components phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were decreased and lysophosphatidylcholine (LPC), a major breakdown product of phospholipid metabolism, was increased in schizophrenic patients compared to healthy and to psychiatric controls, suggesting a specificity of the findings for schizophrenia. During the first 3-weeks on antipsychotic drug treatment LPC levels decreased to control values, but increased again during the following 6 months, reaching significantly higher levels than controls at the end of this period. Thus, at least in peripheral cells an increased breakdown of phospholipids in schizophrenia appears to be present during the acute episode, being influenced only by initial antipsychotic treatment, but without evidence of a long lasting treatment effect on membrane metabolism. Received October 10, 2000; accepted March 13, 2001     

Triacylglycerides and Phospholipids from Egg Yolk Differently Influence the Immunostimulating Properties of Egg White Proteins

As part of a whole egg, egg white proteins are embedded in a lipid matrix that could modify their presentation to the immune system and their allergenic properties. The present study examines the impact of the main egg lipid components, triacylglycerides and phospholipids, in the early events of sensitization to egg. To this end, BALB/c mice were exposed intragastrically to egg lipids and egg lipid fractions, alone and in mixtures with egg white proteins, and Th2-promoting and proinflammatory effects were investigated. Our results highlight that the egg lipid fraction is responsible for Th2 adjuvant effects and point at a different influence of triacylglycerides and phospholipids on the bioavailability and immunomodulating properties of egg white proteins. While triacylglycerides promote type 2 responses at the small intestine level, phospholipids reduce the solubility of EW proteins and induce Th2 skewing in lymphoid intestinal tissues, which may have a direct impact on the development of egg allergy.     

Proportions of Polyunsaturated Fatty Acids in Umbilical Cord Blood at Birth Are Related to Atopic Eczema Development in the First Year of Life

Atopic eczema, the most common atopic disease in infants, may pave the way for sensitization and allergy later in childhood. Fatty acids have immune-regulating properties and may regulate skin permeability. Here we examine whether the proportions of fatty acids among the infant and maternal plasma phospholipids at birth were associated with maternal dietary intake during pregnancy and development of atopic eczema during the first year of age in the Nutritional impact on Immunological maturation during Childhood in relation to the Environment (NICE) birth cohort. Dietary data were collected with a semi-quantitative food frequency questionnaire, fatty acids were measured with GC-MS and atopic eczema was diagnosed by a pediatric allergologist at 12 months of age. We found that higher proportions of n-6 PUFAs (including arachidonic acid) but lower proportions of n-3 PUFAs (including DPA) in the infant’s phospholipids at birth were associated with an increased risk of atopic eczema at 12 months of age. The n-6 and n-3 PUFAs were related to maternal intake of meat and fish, respectively. Our results suggest that prenatal exposure to unsaturated fatty acids is associated with eczema development in the infant. Maternal diet during pregnancy may partly explain the fatty acid profiles in utero.     

Total Fatty Acid and Polar Lipid Species Composition of Human Milk

Human milk lipids are essential for infant health. However, little is known about the relationship between total milk fatty acid (FA) composition and polar lipid species composition. Therefore, we aimed to characterize the relationship between the FA and polar lipid species composition in human milk, with a focus on differences between milk with higher or lower milk fat content. From the Norwegian Human Milk Study (HUMIS, 2002–2009), a subset of 664 milk samples were analyzed for FA and polar lipid composition. Milk samples did not differ in major FA, phosphatidylcholine, or sphingomyelin species percentages between the highest and lowest quartiles of total FA concentration. However, milk in the highest FA quartile had a lower phospholipid-to-total-FA ratio and a lower sphingomyelin-to-phosphatidylcholine ratio than the lowest quartile. The only FAs associated with total phosphatidylcholine or sphingomyelin were behenic and tridecanoic acids, respectively. Milk FA and phosphatidylcholine and sphingomyelin species containing these FAs showed modest correlations. Associations of arachidonic and docosahexaenoic acids with percentages of phosphatidylcholine species carrying these FAs support the conclusion that the availability of these FAs limits the synthesis of phospholipid species containing them.     

Interactions of anti-DNA antibodies with Z-DNA

Systemic lupus erythematosus (SLE) sera, two classes of serum lipoproteins, and IgG antibodies from SLE and normal sera were tested for their reactivity with a Z-DNA polymer, Br-poly (dG-dC). In all cases preferential binding to Z-DNA over B-DNA was observed. This interaction, for the most part, could be inhibited by the negatively charged phospholipid, cardiolipin, which suggests that most of the anti-Z-DNA activity associated with sera arises from relatively non-specific ionic interactions between proteins and polyanionic molecules. An assay has been described that can eliminate proteins cross-reactive with negatively charged phospholipids.     

Phospholipid composition and organization in model β-thalassemic erythrocytes

The membrane phospholipid organization in human red blood cells (RBC) is rigidly maintained by a complex system of enzymes. However, several elements of this system are sensitive to oxidative damage. An important component in the destruction of β-thalassemic RBC is the generation of reactive oxygen species and the release of redox-active iron by the unpaired α-hemoglobin chains. Consequently, we hypothesized that the presence of this oxidative stress to the RBC membrane could lead to alterations in membrane lipid organization. Model β thalassemic RBC, prepared by the introduction of excess α-globin in the cell, have previously been shown to exhibit structural and functional changes almost identical to those observed in β-thalassemic cells. After 24 hr at 37°C, the model β thalassemic cells exhibited a significant loss of deformability, as measured by ektacytometric analysis, indicative of extensive membrane damage. However, a normal steady-state distribution of endogenous phospholipids was found, as evidenced by the accessibility of membrane phospholipids to hydrolysis by phospholipases. Similarly, the kinetics of transbilayer movement of spin-labeled phosphatidylserine (PS) and phosphatidylethanolamine (PE) in all samples was in the normal range and was not affected by the presence of excess α-globin chains. In contrast, a faster rate of spin-labeled phosphatidylcholine (PC) transbilayer movement was observed in these cells. While control RBC exhibited a complete loss of their initial (2 mol%) lysophosphatidylcholine (LPC) levels following 24 hr of incubation at 37°C, 1.5 mol% LPC was still present in model β-thalassemic cells, suggesting an altered phospholipid molecular species turnover, possibly as a result of an increased repair of oxidatively damaged phospholipids. © 1996 Wiley-Liss, Inc.