bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intralipid alters macrophage membrane fatty acid composition and inhibits complement (C2) synthesis
Authors: Strunk R. C. , Kunke K. S. , Kolski G. B. , Revsin B. K. 
Published: December 2006

AbstractIntralipid (IL) is a soybean oil emulsion commonly used as a parenteral nutrient. IL is taken up by macrophages. These cells are a site of synthesis of several of the proteins in the complement system, a major mediator of the humoral system. These studies were undertaken to determine whether IL has an effect on the production of the second (C2) and the fourth (C4) components of complement by guinea pig and human macrophages in vitro. Guinea pig macrophages incubated with IL, in concentrations from 5 to 40 mg/dl, produced significantly decreased amounts of C2 and C4 when compared with controls (decreases from 40% at 5 mg/dl to 60% at 40 mg/dl). Human macrophages incubated in IL, 19 or 38 mg/dl, also produced significantly decreased amounts of C2 when compared to controls (decreases were 45 and 50% at 19 and 38 mg/dl, respectively). The maximum concentration of IL used in these studies did not significantly affect cell viability, or the production of lysozyme or β‐glucosaminidase. For human macrophages, which were studied more thoroughly, the inhibition of C2 production was reversible. C2 levels returned to normal after removal of IL. Cells stimulated with opsonized zymosan produced levels of C2 comparable to stimulated control cells, despite the continued presence of IL within the cells. Human macrophages incubated with arachidonic acid, in addition to IL, produced C2 as well as control cells did. Thus, IL appears to have a selective, reversible effect on C2 production. It is possible that a general increase in fat metabolism, in response to the ingestion of IL, nonspecifically consumed arachidonic acid, decreasing its availability as a substrate for a cell product important in production of C2. Since the effects on C2 production were seen with concentrations of IL commonly seen in plasma of infants receiving IL intravenously, these studies have implications for the clinical use of oil emulsions in parenteral nutrition.
Stearoyl‐CoA desaturase activity in adipose tissue and liver of the cardiomyopathic hamster
Authors: Barakat Hisham A. , Brown William E. , Debnath Sadhana 
Published: December 2006

AbstractStearoyl‐CoA desaturase activity and the fatty acid composition of lipids of adipose tissue and liver were determined in 35‐ and 180‐day‐old cardiomyopathic hamsters and age‐matched normal controls. Enzyme activity was unchanged in the adipose tissue of 35‐day‐old animals but was significantly depressed in the 180‐day‐old cardiomyopathic hamsters. In the liver, stearoyl‐CoA desaturase activity was significantly lower in the 35‐day‐old disease animals but was unchanged in the 180‐day‐old animals. The analysis of the fatty acid composition of the lipids isolated from adipose tissue showed an increase in the relative percentage of saturated fatty acids accompanied by a decrease in the relative percentage of unsaturated fatty acids in both age groups of the cardiomyopathic hamsters. However, linoleic acid content was increased in the diseased animals. Similar changes in fatty acid composition of lipids from the livers of 35‐day‐old cardiomyopathic hamsters were observed, but no significant differences in the fatty acid composition between 180‐day‐old cardiomyopathic hamsters and normal controls were observed. The changes in the fatty acid composition appear to be related to the observed changes in desaturase activity. In is concluded that such changes in desaturase activity and fatty acid composition could affect the normal structure and functions of membranes and membrane‐related processes.
Gas chromatographic separations of di‐ and monoacylglycerols based on the degree of unsaturation and positional placement of acyl groups
Authors: Itabashi Yutaka , Takagi Toru 
Published: December 2006

AbstractGas liquid chromatographic analysis of diacylglycerols (DGs) and monoacylglycrols (MGs) prepared by Grignard degradation of the triacylglycerols of plant and fish oils was examined as acetate and trimethylsilyl (TMS) ether derivatives on several polar cyanosiloxanes. Satisfactory separations of mixtures of DGs or MGs from simple plant oils based on carbon number and degree of unsaturation, as either acetates or TMS ethers, were obtained on SILAR 10C. In addition, the TMS ethers were effectively separated on the basis of the positional distribution of fatty acid in the acylglycerol molecule, but the acetates of the positional isomers overlapped. The equivalent chain lengths (ECLs) of DGs with 28–42 total acyl carbons and 0–6 double bonds, and MGs with 14–22 acyl carbons and 0–6 double bonds, are presented for both derivatives. The influence of column temperature on the ECLs is discussed.
Effect of dietary taurine on bile acid metabolism in guinea pigs
Authors: Kibe Akihiro , Wake Chieko , Kuramoto Taiju , Hoshita Takahiko 
Published: December 2006

AbstractThe effect of oral administration of taurine (200–300 mg daily) on the metabolism of bile acids was studied in male guinea pigs which have predominantly glycine conjugated bile acids. The results were summarized as follows: (a) oral administration of taurine for 10 days increased taurine‐conjugated bile acids and the ratio of glycine‐to taurine‐conjugated bile acids (G:T ratio) shifted from 3.95 to 0.19; (b) in taurine fed guinea pigs, the half‐life of chenodeoxycholic acid (CDC) was about 40% shorter than that in controls and the fractional turnover rate increased by 70%; (c) the synthetic rate (mg/day/500 g body weight) of bile acids increased from 4.28 to 7.27 by taurine feeding; (d) hepatic cholesterol 7α‐hydroxylase activity was increased 2.4‐fold by taurine feeding; (e) the total pool size of bile acids did not change significantly but the amount of lithocholic acid in the caecum and large intestine increased by about 40%; (f) neither free cholesterol nor cholesterol ester levels in liver and serum changed significantly. Results of this study suggest that changing the G:T ratio in the bile acid conjugation pattern may influence the rate of hepatic bile acid synthesis.
Effects of diet and high density lipoprotein subfractions on the removal of cellular cholesterol
Authors: Jackson Richard L. , Glueck Charles J. , Mathur Satya N. , Spector Arthur A. 
Published: December 2006

AbstractThe effects of isocaloric substitutions of dietary polyunsaturated and saturated fat on the composition and function of plasma high density lipoproteins (HDLs) were studied in 3 normal subjects who were fed saturate‐rich and polyunsaturate‐rich diet programs. Compared to the saturated diets (P/S=0.4), polyunsaturated fat diets (P/S=4 or 2) reduced both plasma cholesterol and triglyceride levels. In 2 of the subjects, HDL cholesterol concentrations increased with polyunsaturated fat caused a reduction in HDL fatty acyl content of oleate and an increase in linoleate. To determine whether the altered composition affected the removal of cell membrane cholesterol, HDL and their subfractions, HDL2 and HDL3, which were isolated from each of the diets, were incubated with Ehrlich ascites cells in vitro. The cells were prelabeled with [3H] cholesterol, and the release of labeled cholesterol from the cells into the medium containing the various HDL fractions was determined. HDL, irrespective of the type of dietary fat, caused a release of [3H] cholesterol from the cells into the medium. The amount of [3H] cholesterol recovered in the medium was dependent on the absolute concentration of HDL cholesterol added to the cells and was independent of the type of diet. These results indicate that HDL facilitates the removal of cholesterol from cells, but that the amount and rate of removal are independent of the changes in HDL composition that can be obtained by dietary perturbations.
Erucic acid‐induced alteration of cardiac triglyceride hydrolysis
Authors: Stam Hans , Geelhoed‐Mieras Tiny , Hülsmann Willem C. 
Published: December 2006

AbstractMale Wistar rats were fed for 3 or 10 days with high erucic acid rapeseed oil (HEAR) or trierucate (TE). These diets produced increased myocardial triglyceride (TG) levels. Cardiac lipid accumulation was related to basal‐and hormone‐ (glucagon, norepinephrine) stimulated lipolysis, determined as glycerol release, which proved to be enhanced in isolated, perfused hearts from HEAR‐ and TE‐fed rats. Endogenous TG levels in isolated hearts from rats fed the stock and the sunflowerseed oil (SSO) diet were low and probably rate‐limiting for tissue lipolytic activities. HEAR feeding of rats did not modify the rate of erucic acid (22∶1) oxidation in heart. Prolonged HEAR and TE feeding led to a decrease in the endogenous TG level, a process in which the increased rate of TG hydrolysis might play an important role. The enhanced breakdown of tissue TG in hearts from TE‐and HEAR‐fed rats was accompanied by an increased release of fatty acids into the coronary effluent. Erucic acid was a major constituent of the perfusate fatty acids. Evidence is presented that the site of the intracellular TG breakdown is associated with lysosomes, since a subcellular fraction enriched in acid lipase, N‐acetyl‐β‐glucosaminidase and TG could be isolated from heart homogenates of TE‐fed rats. Fatty acids seemed to be an important regulator of tissue lipase activity: palmitate inhibited glucagon‐stimulated lipolysis, which suggests the tissue lipase is subject to product inhibition by fatty acids.
Lipids of myelin, white matter and gray matter in a case of generalized deficiency of cytochrome b5 reductase in congenital methemoglobinemia with mental retardation
Authors: Hirono H. 
Published: December 2006

AbstractThe lipid classes and fatty acid compositions of myelin, white matter and gray matter were analyzed in a case of generalized deficiency of cytochrome b5 reductase in congenital methemoglobinemia with mental retardation. When compared with normal data, the percentage of 24∶1 was considerably decreased and diminished unsaturation was observed in cerebrosides, whereas the sum of 24∶0 and 24∶1 was the same as in normals. The ratio of hydroxy fatty acids to total fatty acids in cerebrosides was low. The contents of cholesterol and phospholipids in white matter were reduced to 80% of the normal, whereas cerebroside was reduced to 48% of the normal.
Phospholipid composition of liver in rats fed high levels of 13‐cis retinoic acid
Authors: Alam Bassima S. , Alam Syed Q. 
Published: December 2006

AbstractThe composition of liver phospholipids was studied in rats fed for 4 weeks diets containing 0, 100 or 300 mg 13‐cis retinoic acid per kg diet. There was a significant decrease in phosphatidylcholine content, whereas the levels of phosphatidylethanolamine were slightly increased in liver phospholipids of rats fed 13‐cis retinoic acid. The fatty acid composition of total phospholipids, PC, PE, and PI+PS fractions revealed a general increase in the levels of 18∶2 and 20∶3ω6, whereas the levels of 20∶4ω6 and C22 fatty acids were reduced in most of the hepatic phospholipids isolated from rats fed 13‐cis retinoic acid containing diets. A decrease in the double‐bond index of fatty acids was also observed in phospholipids of rats fed 13‐cis retinoic acid. The data suggest that high levels of 13‐cis retinoic acid may possibly be influencing the activities of microsomal desaturating and chain‐elongating enzymes in the liver.
Effect of dietary vitamin E on sulfolipid synthesis in rat submandibular salivary gland
Authors: Pritchard E. T. , Chan A. C. 
Published: December 2006

AbstractThe effect of feeding diets containing various levels of vitamin E for 6 months on the in vitro synthesis of sulfolipids in rat submandibular salivary glands (SMG) was elucidated. The incorporation of [35S]sulfate into sulfolipid of SMG from rats on deficient or “normal” vitamin E diets was quite similar, however, the uptake was significantly increased in glands from rats on diets high in vitamin E. Whereas, in many instances, antioxidants can mimic the effect of vitamin E, in the present study, the antioxidant N,N′‐diphenyl‐ρ‐phenylene diamine (DPPD) was actually found significantly to depress sulfolipid‐labeling below that noted in SMG from all other diets. The results suggest that in the synthesis of SMG sulfolipid the action of vitamin E may be more than that of a simple antioxidant.
Differential effects of eicosapentaenoic acid and docosahexaenoic acid on human skin fibroblasts
Authors: Brown Eric R. , Subbaiah Papasani V. 
Published: December 2006

AbstractTo better understand the mode of action of ω3 fatty acids in cell membranes, human foreskin fibroblasts were grown in serum‐free medium supplemented with 50 μM oleic acid linoleic acid, eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), and the effects on membrane composition, fluorescence polarization and enzyme activities were followed. The cells were enriched with EPA and DHA up to 7 and 13% of total lipids, respectively, of which >95% was associated with phospholipids. In addition, the concentration of 22∶5n−3 increased with both EPA and DHA to 7.5, and 2.1% of the total fatty acids, respectively. When compared to controls (oleic acid), cells treated with DHA showed a decrease in cholesterol, phospholipids, arachidonic acid (AA) and free cholesterol/phospholipid ratio (P<0.05). In the presence of EPA, only decreases in AA and cholesterol were significant (P<0.05). Membrane fluidity, assessed by fluorescence anisotropy, was increased 16% in cells enriched with DHA (P<0.05), but showed no change with EPA or linoleic acid. There was an increase in membrane‐associated 5′‐nucleotidase (+27%) and adenylate cyclase (+19%) activities (P<0.05), in DHA‐enriched, but not in EPA‐enriched cells, when compared with oleate controls. The studies show that incorporation of DHA, but not EPA, into cell membranes of fibroblasts alters membrane biophysical characteristics and function. We suggest that these two major n−3 fatty acids of fish oils have differential effects on cell membranes, and this may be related to the known differences in their physiological effects.
Comparison of linoleic acid and eicosapentaenoic acid incorporation into human breast cancer cells
Authors: Hatala Mary Ann , Rayburn Jodie , Rose David P. 
Published: December 2006

AbstractTo gain some insight into the mechanisms involved in the opposing effects of linoleic acid (LA) and eicosapentaenoic acid (EPA) on the growth and invasiveness of MDA‐MB‐435 human breast cancer cells, the dynamics of the uptake by cells and the incorporation of [14C]LA and [14C]EPA into major lipid and phospholipid pools, as well as the effects of unlabeled EPA or LA on the uptake and distribution of [14C]LA or [14C]EPA, respectively, were examined. Cells were exposed to [14C]LA (1.28 μg/mL) or [14C]EPA (1.0 μg/mL) and unlabeled EPA or LA, respectively, at 0, 1, 4 and 16 μg/mL for 24 h in serum‐free media. The uptake of each fatty acid (FA) was linear over time and was not affected by the presence of the opposing FA. For both FA, 80–90% was incorporated into the phospholipid fraction with the remaining 10–20% in neutral lipids. The relative distribution profile of [14C]LA among the phospholipid classes indicated a preferential incorporation into phosphatidylcholine (65%), whereas [14C]EPA was mostly found in phosphatidylethanolamine (58%). In the presence of unlabeled EPA or LA at various concentrations, corresponding dose‐dependent shifts of [14C]LA or [14C]EPA from the phospholipid to the neutral lipid pool were noted, which did not alter the relative distribution of the FA among the phospholipid classes. Exogenous exposure to EPA or LA increased its content in membrane phospholipids while concurrently decreasing LA or EPA content, respectively, in a dose‐dependent manner. Arachidonic acid content of membrane phospholipids remained constant. The divergent distribution profiles of LA and EPA within the phospholipid compartment provides some insight into the mechanisms of their opposing effects on MDA‐MB‐435 cell growth and invasiveness. Also, the effects of LA and EPA on the uptake and distribution of their opposing FA shed some light on the mechanisms mediating their competitive effects.
Dietary ω3 fatty acids and cholesterol modify enterocyte microsomal membrane phospholipids, cholesterol content and phospholipid enzyme activities in diabetic rats
Authors: Keelan M. , Doring K. , Tavernini M. , Wierzbicki E. , Clandinin M. T. , Thomson A. B. R. 
Published: December 2006

AbstractDiabetes‐associated changes in intestinal uptake of nutrients are modified by isocaloric variations in the type of dietary lipids, and are associated with alterations in the phospholipid and fatty acyl content of the intestinal brush border membrane. The present study was designed to test the hypothesis that diet‐ and diabetes‐associated changes in enterocyte microsomal membrane phospholipids are due to variations in the activity of two phospholipid metabolizing enzymes, 1,2‐diacylglycerol: CDP choline cholinephosphotransferase (CPT) and phosphatidylethanolamine methyltransferase (PEMT). Adult female Wistar rats were fed one of four semisynthetic diets—beef tallow low in cholesterol (BT), beef tallow high in cholesterol (BTC), fish oil low in cholesterol (FO) or fish oil high in cholesterol. In half of the animals, diabetes mellitus was produced by injection of streptozotocin. Jejunal and ileal enterocyte microsomes (EMM) were isolated and analyzed for cholesterol and phospholipids, as well as for CPT and PEMT activities. In control animals, feeding FO reduced EMM total phospholipids including phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol. Feeding FO resulted in a greater than 95% reduction in the activity of CPT. Diabetes was associated with increased jejunal EMM total phospholipids including sphingomyelin (SM) and PE, without associated changes in CPT or PEMT. Dietary cholesterol supplementation did not effect EMM total cholesterol or phospholipid composition in control rats fed BT or FO, but was associated with an increase in EMM cholesterol in diabetic rats fed BT or FO. A decrease in total phospho‐lipids due to a decline in SM, PC and PE in diabetic rats fed FO was not associated with changes in the activities of CPT or PEMT in EMM. Thus (i) enterocyte microsomal membrane cholesterol and phospholipid contents are influenced by diabetes, dietary cholesterol and the type of fatty acid in the diet, and (ii) changes in phospholipid composition are not fully explained by alterations in the activities of CPT and PEMT.
Peroxidation reactions in plant membranes: Effects of free fatty acids
Authors: Barclay Katherine D. , McKersie Bryan D. 
Published: December 2006

AbstractFree fatty acids accumulate in plant membranes after exposure of plants to environmental stress, such as freezing and desiccation. Fatty acid accumulation has been linked to various biophysical changes and to the occurrence of lipid peroxidation, but the relationships appear complex and inconsistent. The interactions between oxygen free radicals, free fatty acids and lipid peroxidation in plant membranes were examined further by studying peroxidation reactions in a model membrane system composed of a complex mixture of plant phospholipids, including various free fatty acids. Multilamellar liposomes were treated with oxygen free radicals generated from iron ascorbate. Increased concentrations of free palmitic acid up to 10 mol% (fatty acid/phospholipid) reduced the production of aldehydes detected by the thiobarbituric acid assay, but enhanced the production of fluorescent products. By contrast, increased concentrations of free linolenic acid increased aldehyde production and reduced the formation of fluorescent products. The two free fatty acids both enhanced the susceptibility of phospholipids to degradation as shown by the reduced recovery of esterified polyunsaturated fatty acids (linoleic and linolenic). The free radical reactions with or without free fatty acid additions catalyzed the selective degradation of phospholipids in the order phosphatidylethanolamine > phosphatidylcholine > phosphatidylinositol > phosphatidylglycerol. Selective degradation of phospholipids is often observed after periods of environmental stress or during senescence of plants, and has been cited as evidence for the involvement of phospholipases in these degenerative processes. The results indicate that selectivity is not a criterion for eliminating the involvement of oxygen free radicals in these degenerative processes. Furthermore, the results suggest that modifications of lipid composition during a plant's acclimation to adverse environments may determine the types of free radical reactions that occur due to stress.
Ultrasound in fatty acid chemistry: Synthesis of a 1‐pyrroline fatty acid ester isomer from methyl ricinoleate
Authors: Lie Ken Jie Marcel S. F. , Syed‐Rahmatullah M. S. K. , Lam C. K. , Kalluri P. 
Published: December 2006

AbstractA novel 1‐pyrroline fatty acid ester isomer [viz. 8‐(5‐hexyl‐1‐pyrrolin‐2‐yl)octanoate] has been synthesized from methyl ricinoleate by two routes with an overall yield of 42 and 30%, respectively. Most of the reactions are carried out under concomitant ultrasonic irradiation (20 KHz,ca. 53 watts/cm2). Under such a reaction condition, the reaction time is considerably shortened, and product yields are high. Dehydrobromination under concomitant ultrasonic irradiation of methyl 9,10‐dibromo‐12‐hydroxyoctadecanoate with KOH in EtOH furnishes methyl 12‐hydroxy‐9‐octadecynoate (66%) within 15 min. Hydration of the latter under ultrasound with mercury(II)acetate in aqueous tetrahydrofuran yields exclusively methyl 12‐hydroxy‐9‐oxo‐octadecanoate (95%) in 30 min. The hydroxy group in the latter compound is transformed to the azido functionvia the mesylate, and treatment of the azido‐oxo intermediate (methyl 12‐azido‐9‐oxooctadecanoate) with Ph3P under ultrasonic irradiation furnishes the requisite 1‐pyrroline fatty acid ester (77%). The same azido‐oxo intermediate has also been obtained by the oxidation of methyl 12‐azido‐9‐cis‐octadecenoate using benzoquinone and a catalytic amount of Pd(II)chloride in aqueous tetrahydrofuran under concomitant ultrasonic irradiation (90 min) to give the product in 45% yield. The latter reaction does not take place even under prolonged silent stirring of the reaction mixture.
An addition compound of oxidized tocopherol and linoleic acid
Authors: Porter W. L. , Levasseur L. A. , Henick A. S. 
Published: December 2006

AbstractThere is evidence that an addition compound of oxidizeddl‐alpha‐tocopherol and linoleic acid is formed when the components are absorbed in mixed monolayer on silica gel at a molecular ratio of 1∶20, and subjected to heating in air at 80C. A relatively nonpolar tocopheryl quinone is also formed in smaller amounts. These are the major tocopherol oxidation products isolated in this system and do not correspond to any known to the authors. The addition compound has about the same mobility as linoleic acid in most thin layer chromatography (TLC) and chromatographic systems, but can be isolated by successive chromatography on silica and gel filtration on Sephadex LH‐20. It yields a single spot in TLC in several systems. The elemental analysis is reproducible and consistent with a simple addition compound of linoleic acid and bivalently oxidized tocopherol. The compound has a carboxyl group which can be esterified. The ester has about the same TLC mobility as methyl linoleate. The molecular weight of the ester is 722.6. The UV spectrum shows a single peak, 2maxETOH=3000 Å, E=4.74. The IR spectrum shows a very strong chroman ether band at 9.12 μ, a strong methyl band at 7.24 μ and carboxyl but no hydroxyl absorption. The NMR spectrum shows, in contrast to that of tocopherol, a reduction in aromatic methyl protons, a carboxyl proteon exchangeable with deuterium oxide, but no hydroxy proton. The compound does not reduce Emmerie‐Engel reagent prior to treatment with concentrated hydriodic acid, nor do the ether‐extractable products after such treatment. The present data are consistent with an addition product whose bridging group is a new chroman ring.