bluuebunny/crossref_metadata_2025 huggingface dataset:
Occurrence of 22∶3n−9 and 22∶4n−9 in the lipids of the topminnow (Poeciliopsis lucida) hepatic tumor cell line, PLHC‐1
Authors: Tocher Douglas R. , Dick James R. , Sargent John R.
Published: November 2006

The lipids of the hepatic tumor cell line, PLHC‐1, from the topminnow (Poeciliopsis lucida), were found to contain considerable amounts of a range of n−9 polyunsaturated fatty acids despite culture in serum containing significant amounts of essential fatty acids. The structural identity of all the n−9 polyunsaturated fatty acids was confirmed by gas chromatography/mass spectrometry. Of particular interest, PLHC‐1 cell total lipid contained 1.9% of 22∶3n−9 and 3.3% of 22∶4n−9. As the culture medium contained virtually no n−9 polyunsaturated fatty acids, these fatty acids are all formed by the PLHC‐1 cells, presumably form 18∶1n−9. The 22∶3n−9 and 22∶4n−9 are presumably formed by processes of elongation and “Δ4” desaturation of Mead acid, 20∶3n−9, present at over 11% in fatty acids of total lipid. Both 22∶3n−9 and 22∶4n−9 were primarily located in phosphatidylserine (4.1 and 8.5% respectively) and, to a lesser extent, in phosphatidylethanolamine (2.2 and 6.5%, respectively), in common with the C22derivatives of the n−3 and n−6 series, whereas 20∶3n−9 was preferentially located in phosphatidylinositol (31.2%). The results establish that long‐chain polyunsaturated fatty acids of the n−9 series can be formed in vertebrate tissue other than in conditions of classical essential fatty acid deficiency.
Very long chain fatty acids in higher animals—A review
Authors: Poulos Alf
Published: November 2006

Fatty acids with greater than 22 carbon atoms (very long chain fatty acids, VLCFA) are present in small amounts in most animal tissues. Saturated and monoenoic VLCFA are major components of brain, while the polyenoic VLCFA occur in significant amounts in certain specialized animal tissues such at retina and spermatozoa. Biosynthesis of VLCFA occurs by carbon chain elongation of shorter chain fatty acid precursors while β‐oxidation takes place, almost exclusively in peroxisomes. Mitochondria are unable to oxidize VLCFA because they lack a specific VLCFA coenzyme A synthetase, the first enzyme in the β‐oxidation pathway. VLCFA accumulate in the tissues of patients with inherited abnormalities in peroxisomal assembly, and also in individuals with defects in enzymes catalyzing individual reactions along the β‐oxidation pathway. It is believed that the accumulation of VLCFA in patient tissues contributes to the severe pathological changes which are a feature of these conditions. However, little is known of the role of VLCFA in normal cellular processes, and of the molecular basis for their contribution to the disease process. The present review provides an outline of the current knowledge of VLCFA including their biosynthesis, degradation, possible function and involvement in human disease.
Trans fatty acid isomers in Canadian human milk
Authors: Chen Z. ‐Y. , Pelletier G. , Hollywood R. , Ratnayake W. M. N.
Published: November 2006

The fatty acid composition, totaltrans content (i.e., sum of all the fatty acids which may have one or moretrans double bonds) and geometric and positional isomer distribution of unsaturated fatty acids of 198 human milk samples collected in 1992 from nine provinces of Canada were determined using a combination of capillary gas‐liquid chromatography and silver nitrate thin‐layer chromatography. The mean totaltrans fatty acid content was 7.19±3.03% of the total milk fatty acids and ranged from 0.10 to 17.15%. Twenty‐five of the 198 samples contained more than 10% totaltrans fatty acids, and thirteen samples contained less than 4%. Totaltrans isomers of linoleic acid were 0.89% of the total milk fatty acids with 18∶2Δ9c, 13t being the most prevalent isomer, followed by 18∶2Δ9c, 12t and 18∶2Δ9t, 12c. Using the totaltrans values in human milk determined in the present study, the intake of totaltrans fatty acids from various dietary sources by Canadian lactating women was estimated to be 10.6±3.7 g/person/d, and in some individuals, the intake could be as high as 20.3 g/d. The 18∶1trans isomer distribution differed from that of cow's milk fat but was remarkably similar to that in partially hydrogenated soybean and canola oils, suggesting that partially hydrogenated vegetable oils are the major source of thesetrans fatty acids.
Thermal acclimation and dietary lipids alter the composition, but not fluidity, of trout sperm plasma membrane
Authors: Labbe C. , Maisse G. , Müller K. , Zachowski A. , Kaushik S. , Loir M.
Published: November 2006

The effect of a long‐term adaptation of rainbow trout to 8 and 18°C combined with a corn oil‐or a fish oil‐supplemented diet on the characteristics of the spermatozoan plasma membrane was investigated. The experiment lasted up to 22 mon during which spermatozoa were collected from the mature males. Spermatozoan plasma membranes were isolated by nitrogen cavitation, and the cholesterol content, phospholipid composition and fatty acid pattern were investigated. Membrane viscosity was assessed on whole cells by electron spin resonance using spin‐labeled phospholipids. Neither diet nor rearing temperature influenced the cholesterol content of the plasma membrane nor the phospholipid class distribution. The rearing temperature of the broodstock only slightly affected the phospholipid fatty acids. A minor decrease in 18∶0 and increase in monounsaturated fatty acids was observed for the cold‐adapted fish. These modifications were not sufficient to affect membrane fluidity, and we conclude that trout spermatozoa do not display any homeoviscous adaptations in these conditions. On the contrary, the dietary fatty acid intake greatly modified the fatty acid profile of plasma membrane phospholipids. The fish oil‐fed trout displayed a much higher n−3/n−6 fatty acid ratio than did the corn oil‐fed ones, but the 22∶6n−3 levels remained unchanged. Modifications in plasma membrane composition by the diet were obtained although neither of the two diets was deficient in essential fatty acids. The enrichment in n−3 fatty acids, however, did not affect plasma membrane fluidity which was unchanged by the diets.
ω‐3 Fatty acids in smooth muscle cell phospholipids increase membrane cholesterol efflux
Authors: Dusserre Eric , Pulcini Thérèse , Bourdillon Marie‐Claude , Ciavatti Maryvonne , Berthezene François
Published: November 2006

The aim of our work was to determine whether fatty acid modifications in smooth muscle cell phospholipids affect cholesterol efflux and desorption. [3H]Cholesterol was used to label cholesterol pools in the whole cell or selectively in the plasma membrane. Cells were incubated for 12 h in order to increase oleate, linoleate, arachidonate, eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) in phospholipids. Cholesterol efflux was monitored using native or tetranitromethane modified high‐density lipoprotein3 (HDL3). When all cholesterol pools were labeled, the efflux from cells treated with different fatty acids were not different. Plasma membrane cholesterol efflux remained unchanged after oleate, linoleate or arachidonate treatments, but was markedly increased after EPA and DHA enrichment, both with native HDL3 and with tetranitromethane‐high‐density lipoprotein. These results suggest that the positive effects of n−3 fatty acid consumption on the atherosclerotic process could be linked in part to an increase in plasma membrane cholesterol efflux from vascular smooth muscle cells.
Inhibition of soybean lipoxygenase‐1 by chain‐breaking antioxidants
Authors: Maccarrone Mauro , Veldink Gerrit A. , Vliegenthart Johannes F. G. , Agrò Alessandro Finazzi
Published: November 2006

The aim of this investigation was to determine whether chain‐breaking antioxidants able to prevent lipid peroxidation can inhibit lipoxygenase‐1 (EC 1.13.11.12). Therefore, the effects of ascorbic acid, 6‐palmitoylascorbic acid and trolox on the enzyme activity were analyzed by means of Lineweaver‐Burk double reciprocal plots and Yoshino's graphical method. The effect of these compounds on the formation of free radicals during lipoxygenase‐1 reaction was investigated as well, by monitoring the enzymic formation of oxodienes. We present evidence that the chain‐breaking antioxidants ascorbic acid, 6‐palmitoylascorbic acid and trolox inhibit soybean lipoxygenase‐1 in the micromolar concentration range (Ki 27, 3 and 18 μM, respectively). The inhibition is competitive, complete and reversible. All three compounds trap the free radicals formed during the lipoxygenase‐catalyzed reaction, which might substantially contribute to their inhibitory ability. These findings can have physiological significance in the light of the lipoxygenase involvement in biomembrane remodelling.
A microsomal membrane component associated with iron reduction in NADPH‐supported lipid peroxidation
Authors: Tampo Yoshiko , Yonaha Masanori
Published: November 2006

This study was conducted to determine whether a factor responsible for reduced nicotinamide adenine dinucleotide phosphate (NADPH)‐supported lipid peroxidation in rat liver microsomes is involved in iron reduction by cooperation with NADPH‐cytochrome P450 reductase. Under anaerobic conditions, NADPH‐dependent reduction of ferric pyrophosphate in microsomes was not dependent on cytochrome P450 levels and was not inhibited by carbon monoxide (CO). All of the iron complexes with chelators such as adenosine 5′‐diphosphate, pyrophosphate, nitrilotriacetate, oxalate or citrate were reduced in microsomes, although in the reconstituted system containing purified NADPH‐cytochrome P450 reductase little or no iron reduction was found. A cytochrome P450‐free fraction from a cholate‐solubilized preparation of microsomes after passage through a laurate sepharose column was required for reduction of iron pyrophosphate in the reconstituted system leading to lipid peroxidation. The iron reduction was not inhibited by CO and was destroyed by heat treatment or trypsin digestion of the fraction. All iron complexes were reduced in the presence of the fraction, using a reducing equivalent of NADPHvia NADPH‐cytochrome P450 reductase. The results indicate that a heat‐labile component, which is probably a protein distinct from cytochrome P450, is associated with iron reduction responsible for lipid peroxidation in microsomes.
Zinc deficiency and activities of lipogenic and glycolytic enzymes in liver of rats fed coconut oil or linseed oil
Authors: Eder Klaus , Kirchgessner Manfred
Published: November 2006

In previous studies, zinc‐deficient rats force‐fed a diet with coconut oil as the major dietary fat developed a fatty liver, whereas zinc‐deficient rats force‐fed a diet with linseed oil did not. The present study was conducted to elucidate the reason for this phenomenon. In a bifactorial experiment, rats were fed zinc‐adequate or zinc‐deficient diets containing either a mixture of coconut oil (70 g/kg) and safflower oil (10 g/kg) (“coconut oil diet”) or linseed oil (80 g/kg) (“linseed oil diet”) as a source of dietary fat, and activities of lipogenic and glycolytic enzymes in liver were determined. In order to ensure adequate food intake, all the rats were force‐fed. Zinc‐deficient rats on the coconut oil diet developed a fatty liver, characterized by elevated levels of triglycerides with saturated and monounsaturated fatty acids. These rats also had markedly elevated activities of the lipogenic enzymes acetyl‐CoA carboxylase, fatty acid synthase (FAS), glucose‐6‐phosphate dehydrogenase (G6PDH), 6‐phosphogluconate dehydrogenase (6PGDH), and citrate cleavage enzyme, whereas activities of malic enzyme and glycolytic enzymes were not different compared with zinc‐adequate rats on the coconut oil diet. In contrast, rats receiving the linseed oil diet had similar triglyceride concentrations regardless of zinc status, and activities of lipogenic enzymes and glycolytic enzymes were not different between the two groups. Zinc‐deficient rats fed either type of dietary fat exhibited statistically significant correlations between activities of FAS, G6PDH, 6PGDH and concentrations of saturated and monounsaturated fatty acids in liver. The concentrations of serum lipids were elevated in zinc‐deficient rats fed either type of dietary fat. These results demonstrate that fatty liver in zinc‐deficient rats on the coconut oil diet is caused by elevated activities of lipogenic enzymes, and not by disturbed lipid secretion from liver. Dietary linseed oil prevents both the elevation of lipogenic enzyme activity and fatty liver in zinc‐deficient rats.
Synthesis and metabolism of sodium 3α,7α‐dihydroxy‐25,26‐bishomo‐5β‐cholane‐26‐sulfonate in the hamster
Authors: Mikami Takahiro , Mosbach Erwin H. , Cohen Bertram I. , Ayyad Nariman , Yoshii Michiko , Kihira Kenji , Hoshita Takahiko
Published: November 2006

This paper reports the chemical synthesis of a new bile acid analogue, namely sodium 3α,7α‐dihydroxy‐25,26‐bishomo‐5β‐cholane‐26‐sulfonate (bishomoCDC‐sul) from chenodeoxycholic acid and describes its metabolism in the hamster. The structure of the new compound was confirmed by proton and carbon‐13 nuclear magnetic resonance spectroscopy. After intravenous infusion of [3H]‐labeled sulfonate into bile fistula hamsters, it was extracted by the liver and secreted into the bile; more than 65% of the radioactivity was recovered in the bile within 1 h. Following intraduodenal administration of the [3H]sulfonate and [14C]chenodeoxycholyltaurine, both compounds were excreted into the bile more slowly; only 41 and 43% of the radioactivity, respectively, were recovered in the bile during the four‐hour experimental period. In contrast, when the labeled compounds were injected into the terminal ileum, both the sulfonate and chenodeoxycholyltaurine were repidly absorbed and secreted into the bile; 84 and 97%, respectively, of the radioactivity were recovered during a four‐hour period. Chromatographic analysis demonstrated that in these short‐term experiments most (>95%) of the sulfonate was secreted into the bile without biotrasformation regardless of the route of administration. When infused intravenously at increasing doses, bishomoCDC‐sul induced cholestasis at an infusion rate of 1 μmol/min/kg. These results suggest that sodium 3α,7α‐dihydroxy‐25,26‐bishomo‐5β‐cholane‐26‐sulfonate was absorbed from the terminal ileum by active transport, extracted by the liver, and secreted into the bile in a manner similar to that of the natural bile acids.
Chemical and enzymatic preparation of acylglycerols containing C18 furanoid fatty acids
Authors: Lie Ken Jie Marcel S. F. , Syed‐Rahmatullah M. S. K.
Published: November 2006

C18 furanoid triacylglycerol [glycerol tri‐(9,12‐epoxy‐9,11‐octadecadienoate)] was prepared by chemical transformation of triricinolein isolated from castor oil. The procedure involved oxidation, epoxidation and cyclization of the epoxy‐keto intermediate with sodium azide and ammonium chloride in aqueous ethanol. The furanoid triacylglycerol was also obtained by esterification of C18 furanoid fatty acid with glycerol using Novozyme 435 (Novo Nordisk A.S., Bagsvaerd, Denmark) as biocatalyst. When Lipozyme (Novo Nordisk A.S.) was used, a mixture of the furanoid 1(3)‐rac‐monoacylglycerol and 1,3‐diacylglycerol was obtained. In order to obtain the C18 furanoid 1,2(2,3)‐diacylglycerol, selective hydrolysis of the furanoid triacylglycerol was achieved using procine pancreatic lipase intris(hydroxymethyl) methylamine buffer. Interesterification of triolein with methyl C18 furanoid ester in the presence of Lipozyme showed maximum incorporation of 34% of furanoid fatty acid. Extension of the interesterification to vegetable oils (olive, peanut, sunflower, corn and palm oil) allowed a maximum of 24% furanoid acid incorporation to be achieved.
Comparative studies of metabolism of 4‐desmethyl, 4‐monomethyl and 4,4‐dimethyl sterols inManduca sexta
Authors: Svoboda James A. , Ross Samir A. , Nes W. David
Published: November 2006

To investigate the metabolism and possible deleterious effects of 4‐methyl and 4,4‐dimethyl steroids inManduca sexta, the 4,4‐dimethyl sterols lanosterol and cycloartenol, the 4‐methyl sterol obtusifoliol and the 4,4‐dimethyl pentacyclic triterpenoid α‐amyrin were fed in an artificial agar‐based diet at various concentrations. Utilization and metabolism of these four compounds were compared with sitosterol, stigmasterol, brassicasterol, ergosterol and 24‐methylenecholesterol, 24‐alkyl sterols that are readily dealkylated and converted to cholesterol inManduca and in most phytophagous insects. None of the 4‐methylated compounds significantly inhibited development except at very high dietary concentrations. The Δ24‐bonds of lanosterol and cycloartenol were effectively reduced by theManduca Δ24‐sterol reductase enzyme, as is the Δ24‐bond of desmosterol which, in most phytophagous insects, is an intermediate in the conversion of sitosterol, stigmasterol and other C28 and C29 phytosterols to cholesterol. On the other hand, the 24‐methylene substituent of obtusifoliol was not dealkylated. Each of the 4‐desmethyl C28 and C29 sterols was readily converted to cholesterol, and a significant amount of 7‐dehydro‐cholesterol was derived from ergosterol metabolism. The reason for the differences in substrate specificity of these sterols is not clear, but the information may be useful in the development of new, specific, mechanism‐based inhibitors of sterol metabolism.
Lipids of selected molds grown for production of n−3 and n−6 polyunsaturated fatty acids
Authors: Kendrick Andrew , Ratledge Colin
Published: November 2006

The lipid classes and component fatty acids of seven fungi were examined. Three marine fungi,Thraustochytrium aureum, Thraustochytrium roseum andSchizochytrium aggregatum (grown at 30, 25 and 25°C, respectively), produced less than 10% lipid but contained docosahexaenoic acid (DHA) up to 30% and eicosapentaenoic acid (EPA) up to 11% of the total fatty acids.Mortierella alpinapeyron produced 38% oil containing solely n‐6 polyunsaturated fatty acids (PUFA) with arachidonic acid (AA) at 11% of the total fatty acids.Conidiobolus nanodes andEntomorphthora exitalis produced 25% oil and contained both n−3 and n−6 PUFA, with AA at 16% and 18%, respectively.Saprolegnia parasitica produced 10% oil and contained AA and EPA, respectively, at 19% and 18%. The triacylglycerol fraction always represented the major component at between 44% and 68% of the total lipid. Each fungus, exceptT. aureum, had the greatest degree of fatty acid unsaturation in the phospholipid fraction. The triacylglycerol fraction ofT. aureum was the most unsaturated with DHA representing 29% (w/w) of all fatty acids present. The presence of the enzyme ATP:citrate lyase correlated with the ability of molds to accumulate more than 10% (w/w) lipid when the fungi were grown in nitrogen‐limiting media. In those molds that failed to accumulate more than 10% lipid, the enzyme was absent.
Linoleoyl‐enriched triacylglycerol species increase in maternal liver during late pregnancy in the rat
Authors: Chen Zhen‐Yu , Yang Jilin , Menard Chantale R. , Cunnane Stephen C.
Published: November 2006

In view of the previously reported changes in the fatty acid composition of maternal liver triacylglycerols in late pregnancy, changes in the composition of maternal liver triacylglycerol species were assessed in rats fed a semipurified diet during pregnancy. Between day 18 and day 21 of pregnancy, total maternal liver triacylglycerols increased by 50%. Triacylglycerol species with a total acyl carbon number (C) of 50 or 60 (C50, C60) remained unchanged while C48 and C52–C58 were relatively increased. The individual triacylglycerol species containing one, two or three linoleoyl moieties were incompletely recovered using a polar high temperature gas‐liquid chromatography (GLC) column. Nevertheless, at day 21 compared to day 18, the linoleoyl‐containing species were relatively increased by 62–463%, while tripalmitin was decreased by 38%. Our data suggest that despite an adequate intake of linoleic acid (25 g/kg in the diet), maternal hepatic triacylglycerol content of linoleic acid decreased during mid‐pregnancy but increased significantly toward term possibly in preparation for the transfer of linoleic acid to the neonate during lactation.
Alteration in mouse splenic phospholipid fatty acid composition and lymphoid cell populations by dietary fat
Authors: Huang Shu‐Cai , Fritsche Kevin L.
Published: November 2006

The fatty acid composition of diacyl‐ and alkylacylglycerophosphocholine (PC), phosphatidylinositol (PI), phosphatidylserine (PS), alkenylacyl‐glycerophosphoethanolamine (aPE), and diacyl‐ and alkylacyl‐glycerophosphoethanolamine (dPE) was assessed in isolated splenocytes from C3H/Hen mice fed one of four purified isocaloric diets for six weeks. Diets contained 20% by weight of either a high‐linoleate sunflower oil (Hi 18∶2), a high‐oleate sunflower oil (Hi 18∶1), a mixture of 17% menhaden fish oil and 3% high‐linoleate sunflower oil (Hi n−3), or a mixture of 17% coconut oil and 3% high‐linoleate sunflower oil (Hi SFA). Spleen weight and immune cell yield were significantly higher (P<0.05) in mice fed the Hi 18∶1 or the Hi n−3 diets compared with those fed the Hi 18∶2 and Hi SFA diets. Distinctive patterns of fatty acids were observed for each phospholipid in response to dietary fatty acids. Dietary fat significantly affected (P<0.05) total polyunsaturated fatty acids (PUFA) in PC and dPE, total saturated fatty acids (SFA) in PC, total monounsaturated fatty acids (MUFA), and n−3 PUFA in all phospholipid classes examined. In mice fed the Hi n−3 diet, n−3 PUFA were significantly elevated, whereas n−6 PUFA decreased in all of the phospholipids. In these mice, eicosapentaenoic acid (EPA) was the predominant n−3 PUFA in PC and PI, whereas docosahexaenoic acid (DHA) was the major n−3 PUFA in aPE and PS. Interestingly, the ratios of n−3/n−6 PUFA in the phospholipids from these mice were 3.2, 2.4, 1.8, 0.8 and 0.8 for aPE, PS, dPE, PC and PI, respectively. These data suggest a preferential incorporation of n−3 PUFA into aPE, PS and dPE over PC and PI.
Comparative uptake of α‐ and γ‐tocopherol by human endothelial cells
Authors: Tran Khai , Chan Alvin C.
Published: November 2006

The intake of γ‐tocopherol by North Americans is generally higher than that of α‐tocopherol. However, the levels of α‐tocopherol in human blood have consistently been shown to be higher than those of γ‐tocopherol suggesting differential cellular retention of the two tocopherol forms. We sought to resolve this question by studying tocopherol metabolism by human endothelial cells in culture. The time‐ and dose‐dependent uptake of γ‐tocopherol by endothelial cells was similar to that of α‐tocopherol. To determine the comparative uptake between α‐ and γ‐tocopherol, we adopted two approaches in which cells were enriched with either increasing concentrations of an equimolar mixture of α‐ and γ‐tocopherol; or cells were enriched with a fixed concentration of tocopherols in which the α to γ ratio was varied. Our results indicated that there was a preferential uptake of γ‐tocopherol by the cells. When cells were enriched with either α‐ or γ‐tocopherol and the disappearance of individual tocopherols was monitored over time, γ‐tocopherol exhibited a faster rate of disappearance. The faster turnover of γ‐tocopherol can explain the discrepancy between high intake and low retention of γ‐tocopherol in man.
The quantitation of long‐chain acyl‐CoA in mammalian tissue
Authors: Tardi Paul G. , Mukherjee Jagat J. , Choy Patrick C.
Published: November 2006

Intracellular long‐chain acyl‐CoA esters are key metabolites in lipid metabolism. A rapid procedure was developed for the isolation of long‐chain acyl‐CoA from mammalian tissues. Acyl‐CoA was extracted from the tissue with chloroform/methanol and separated from other lipid‐containing metabolites by phase partition with solvents. The content and the molecular species of acyl‐CoA were determined by gas‐liquid chromatography. In rat liver and hamster heart, the total acyl‐CoA content was estimated to be 83±11 and 61±9 nmol/g wet weight, respectively. The results obtained are comparable to those reported in previous studies. The relative ease of this procedure would permit the determination of acyl‐CoA contents in a large number of samples.
Incorporation of cyclic fatty acid monomers in lipids of rat heart cell cultures
Authors: Ribot E. , Grandgirard A. , Sébédio J. L. , Grynberg A. , Athias P.
Published: November 2006

Primary cultures of newborn rat cardiomyocytes were grown in medium supplemented with cyclic fatty acid monomers (CFAM) which had been isolated from heated linseed oil. The cells were harvested, and lipids were extracted and fractionated using silica cartridges and high‐performance liquid chromatography. The CFAM structures isolated from cellular lipids were determined and compared to those that had been supplemented to the medium, using gas‐liquid chromatography coupled with mass spectrometry (GC/MS). We found that CFAM were incorporated into phospholipids and neutral lipids of cardiomyocytes. Furthermore, CFAM with a cyclopentyl ring structure were more abundant in cardiomyocytes than were the cyclohexyl ring isomers. Our data suggest that CFAM of the 5‐carbon and 6‐carbon ring series are metabolized differently in newborn rat cardimyocytes.
Gamma linolenic acid (GLA) content of encapsulated evening primrose oil products
Authors: Gibson Robert A. , Lines David R. , Neumann Mark A.
Published: November 2006

The fatty acid composition of 16 brands of evening primrose oil (EPO) capsules was determined by capillary gas chromatography. Fourteen of these EPO brands contained γ‐linolenic acid (GLA) levels between 7% and 10% (mean, 8.7; range, 1.9–10.5%) and there was generally good agreement between the level of GLA claimed by the manufacturer and the level determined by analysis. Low levels of the monoenes 22∶1 and 24∶1 found in some brands may indicate contamination of EPO with borage oil.
Dietary arachidonic and linoleic acids: Comparative effects on tissue lipids
Authors: Whelan J. , Broughton K. S. , Surette M. E. , Kinsella J. E.
Published: November 2006

The effects of preformed dietary arachidonic acid (AA, 20∶4n−6) on murine phospholipid fatty acid composition in tissues capable (liver) and incapable (peritoneal exudate cells, PEC) of desaturating and elongating linoleic acid (LA, 18∶2n−6) to AA were investigated. The results were compared with those obtained on matched animals on LA diets by either substituting or supplementing dietary LA with AA. Modest amounts of AA ethyl ester (0.5 wt%) included in the diet significantly increased tissue phospholipid AA levels by 39% and 57% in the liver and in PEC, respectively. The changes were further enhanced when dietary LA and AA intakes were equivalent,i.e., 57% and 68% in liver and PEC, respectively. This enrichment was observed in all phospholipid classes analyzed, with the greatest impact on phosphatidylcholine. In addition, the doubling of dietary LA had little effect on tissue phospholipid AA levels. The data suggest that while the level of n−6 PUFA may have an important effect on tissue fatty acid composition, the type of n−6 PUFA in the diet could be of greater significance.
Agonist‐induced lipoxin A4 generation: Detection by a novel lipoxin A4‐ELISA
Authors: Levy Bruce D. , Bertram Sherry , Tai H. H. , Israel Elliot , Fischer Andrew , Drazen Jeffrey M. , Serhan Charles N.
Published: November 2006

Lipoxin A4 (LXA4) possesses potent bioactions. To facilitate its detection, an enzyme‐linked immunosorbent assay (ELISA) was developed that proved sensitive and selective. Quantitation by ELISA of LXA4 generated from cellular sources strongly correlated (r=0.99) with values obtained by high‐pressure liquid chromatography (HPLC). We used this LXA4‐ELISA to examine parameters influencing LXA4 generation from endogenous substrates during human platelet‐neutrophil (PLT‐PMN) interactionsin vitro. Agonist‐induced LXA4 production was clearly evident at a PLT‐PMN ratio of 10∶1, and recombinant human granulocyte/monocyte colony stimulating factor‐priming of PMN augmented LXA4 generation 5–6 fold. The chemotactic peptide formylmethionyl‐leucyl‐phenylalanine, platelet‐derived growth factor and arachidonic acid (20∶4n−6) each stimulated formation of immunoreactive LXA4 (iLXA4) in these co‐incubations. The presence of iLXA4 was also evaluatedin vivo in aspirin‐sensitive asthmatic patients who, in a randomized, double‐blind crossover design, underwent nasal lavage after they each ingested a predetermined threshold dose of aspirin or placebo. Aspirin challenge provoked statistically significant increases in iLXA4 in each patient (P<0.005). These results validate the use of a solid‐phase ELISA for detection of LXA4. Furthermore, the use of this ELISA has allowed the first documentation of iLXA4 formation in human subjects with aspirin‐sensitive asthma following specific antigenic challenge.
Triacylglycerol assembly from binary mixtures of fatty acids byApiotrichum curvatum
Authors: Lee Inmok , Hammond Earl G. , Cornette James L. , Glatz Bonita A.
Published: November 2006

To observe how the stereospecific distribution of acyl groups in triglycerides is affected by the composition of fatty acids available for esterification, the oleaginous yeastApiotrichum curvatum was grown on various binary mixture of palmitic, stearic, oleic and linoleic acids as carbon sources, and the yeast triglycerides were analyzed. When oleic acid‐linoleic acid mixtures in various ratios were used as substrates, the yeast grew well, and the composition of the intracellular triglycerides reflected the substrate composition, but more linoleate than oleate was deposited in the triglycerides. Oleate was favored over linoleate at thesn‐2 position of the glycerol. With substrates containing palmitic and stearic acids, the yeast accumulated less oil, and incorporation of stearic acid into the triglycerides also was very limited. When mixtures of palmitic acid‐oleic acid and palmitic acid‐linoleic acid were used as substrates, the yeast triglyceride composition did not reflect that of the substrate, and the accumulation in the yeast of the unsaturated acid in the substrate was favored. Possibly, the yeast had more limited access to solid than to liquid substrates. For oleic acid‐linoleic acid substrates, when the percentages of oleate and linoleate at the three glycerol positions were plottedvs. the percentage of these acyl groups in the total triglyceride, apparent linear relations were observed for most of the range, and the sums of the intercepts and slopes of the three lines for each acyl group were 0 and 3, respectively. Two mathematical models of triglyceride assembly are proposed, both of which fit the experimental data. One model assumes that for a certain proportion of the glycerol molecules, the acyl composition of the threesn positions is rigidly controlled independently of the substrate concentration. The other assumes that the various acyl groups are distributed on the threesn positions of glycerol with different affinities.
Different mechanisms of uptake of stearic acid and cholesterol into rabbit jejunal brush border membrane vesicles
Authors: Burdick S. , Keelan M. , Thomson A. B. R.
Published: November 2006

The rate of uptake of stearic acid and cholesterol solubilized in taurocholic acid (TC) was examined in rabbit jejunal brush border membrane vesicles (BBMV). For stearic acid (18∶0) or cholesterol there was an initial rapid rate of uptake, which reached a plateau within approximately 1 min and remained stable thereafter. At low concentrations of 18∶0 and 20 mM, but not 2 mM, TC, there was a curvilinear relationship between the concentration of 18∶0 and uptake, whereas the relationship between cholesterol uptake and concentration was linear over a wide range of values. When the concentration of TC was held constant at increasing concentrations of 18∶0 or cholesterol, there was a linear increase in the rate of uptake. When the concentration of 18∶0 or cholesterol was held constant and the concentration of TC was increased from 2 to 20 mM, the uptake of 18∶0 declined, but the rate of uptake of cholesterol increased. When the concentrations of 18∶0 plus TC, or cholesterol plus TC, were both increased in unison and their ratio was held constant, their rate of uptake increased. Thus, (i) BBMV may be used to assess the rate of uptake of lipids; (ii) the partitioning of cholesterol from bile acid micelles into the BBMV appears to be by way of “collision” of the cholesterol with the membrane. In contrast, the uptake of 18∶0 from the micelle into the membrane vesicles may be by both the collision and the aqueous/dissociation models; and (iii) 18∶0 uptake may be mediated by both a concentration‐dependent and a concentration‐independent component. Thus, stearic acid and cholesterol seem to be taken up from bile acid micelles into rabbit BBMV by different mechanisms.
Effects oftrans fatty acids on lipid accumulation in 3T3‐L1 cells
Authors: Panigrahi Kalpana , Sampugna Joseph
Published: November 2006

Previous work had shown that dietarytrans fatty acids (tFA) resulted in decreased fat deposition in adipose tissue. This study was conducted to see iftFA influence lipid accumulation in Swiss mouse fibroblast 3T3‐L1 cells, which are widely used as an adipocyte model. Cells were cultured in the presence of experimental or control growth media supplemented with fatty acids complexed to bovine serum albumin. Fatty acid compositions of experimental and control growth media were similar except that the octadecenoates in the control growth media werecis fatty acids, whereas those in the experimental media contained bothcis andtrans fatty acids. Cell‐conditioned media and cellular lipids at the preadipocyte and differentiating adipocyte stages were analyzed. At both stages of development, less fat accumulated, in cells cultured in the presence oftFA, due primarily to a decrease in the nonpolar lipid content of cells exposed totFA, and linoleate to arachidonate ratios were higher in cells supplemented withtFA. Calculations comparing sums of saturated and monounsaturated fatty acids in cells at the differentiating adipocyte stage suggested thattFA may have replaced monoun‐saturated fatty acids in the nonpolar lipid fraction and saturated fatty acids in the polar lipid fraction. The results of these studies are in good agreement with thein vivo effects oftFA seen in previous work with mouse adipose tissue. It was concluded that the 3T3‐L1in vitro model is an appropriate system for further studies oftFA and lipid metabolism in adipose tissue.
Depletion of adipose tissue and peripheral nerve α‐tocopherol in adult dogs
Authors: Pillai Shreekumar R. , Traber Maret G. , Steiss Janet E. , Kayden Herbert J.
Published: November 2006

To assess the relationship between tissue α‐tocopherol depletion and histopathologic or functional changes in nervous tissue, a longitudinal study of male 1‐year‐old beagle dogs, two fed a vitamin E‐deficient diet (0.05±0.02 mg α‐tocopherol/kg;—E dogs) and two fed a vitamin E‐supplemented diet (114±14 mg α‐tocopherol/kg; +E dogs), was carried out. Plasma and adipose tissue α‐tocopherol concentrations neurological examinations, and sensory and motor nerve conduction velocities were determined at approximately 8‐wk, intervals over 109 wk. Tibial nerve α‐tocopherol concentrations were measured at 65 and 109 wk; adjacent sections were examined for histologic changes. In the two—E dogs, plasma α‐tocopherols declined linearly on a semilog plot to <0.1 μg/mL by 109 wk. Plasma α‐tocopherol concentrations were depleted to half of the initial concentrations in approximately 87 d. Adipose tissue α‐tocopherol concentrations (based on wet weight, cholesterol or triglyceride) also declined linearly on semilog plots, and were deleted to half of the initial concentrations in approximately 120 d. Tibial nerve α‐tocopherols (ng/μg cholesterol) in—E dogs decreased to 16% of average +E at 65 wk, and to 2% at 109 wk. neurologic examinations, histologies and nerve conduction velocities were normal in all dogs throughout the study. Our results demonstrate in dogs that depletion of plasma, adipose tissue and nerve α‐tocopherol precedes histologic and functional changes in peripheral nerves during vitamin E deficiency.
α‐tocopherol concentrations of the nervous system and selected tissues of adult dogs fed three levels of vitamin E
Authors: Pillai Shreekumar R. , Traber Maret G. , Steiss Janet E. , Kayden Herbert J. , Cox Nancy R.
Published: November 2006

The effects of dietary vitamin E levels on tissue α‐tocopherol (α−T) concentrations in different parts of the nervous system are largely unknown. Therefore, we measured the α−T contents of nervous and other tissues obtained from beagle dogs fed for two years a vitamin E‐deficient diet (−E, 0.05±0.02 mg vitamin E/kg diet, n=2), a vitamin E‐supplemented diet (+E, 114±14 mg/kg, n=2), or a standard chow diet (En, 74±6 mg/kg, n=3). Brain regions and spinal cords of +E dogs contained about double the α−T concentrations of En dogs, and about 10‐fold those of −E dogs. The various brain regions of −E dogs, compared with En dogs, retained 12–18% of the α−T concentrations, with the exception of the caudal colliculus, which retained 48%. Peripheral nerve α−T concentrations in +E dogs (67 ng/mg wet weight) were nearly 5‐fold higher than in En dogs (13.4±5.9 ng/mg) and 80‐fold higher than in −E dogs (0.8 ng/mg). Within each dietary group, the lowest α−T concentrations in the central nervous system (CNS) were in the spinal cord. Peripheral nerves were the most susceptible to vitamin E repletion or depletion: in +E dogs, nerves contained higher concentrations of α−T than most brain regions; in En dogs, they contained similar concentrations; but in −E dogs, they contained less α−T than most brain regions. Muscles and other tissues of −E dogs retained from 1 to 10% of En values. The studies demonstrate that the CNS conserved α−T compared to peripheral nerves and nonnervous tissues in adult dogs, but contained lower absolute concentrations of α−T compare with most other tissues.
γ‐tocotrienol as a hypocholesterolemic and antioxidant agent in rats fed atherogenic diets
Authors: Watkins T. , Lenz P. , Gapor A. , Struck M. , Tomeo A. , Bierenbaum M.
Published: November 2006

This study was designed to determine whether incorporation of γ‐tocotrienol or α‐tocopherol in an atherogenic diet would reduce the concentration of plasma cholesterol, triglycerides and fatty acid peroxides, and attenuate platelet aggregability in rats. For six weeks, male Wistar rats (n=90) were fed AIN76A semisynthetic test diets containing cholesterol (2% by weight), providing fat as partially hydrogenated soybean oil (20% by weight), menhaden oil (20%) or corn oil (2%). Feeding the ration with menhaden oil resulted in the highest concentrations of plasma cholesterol, low and very low density lipoprotein cholesterol, triglycerides, thiobarbituric acid reactive substances and fatty acid hydroperoxides. Consumption of the ration containing γ‐tocotrienol (50 μ/kg) and α‐tocopherol (500 mg/kg) for six weeks led to decreased plasma lipid concentrations. Plasma cholesterol, low and very low density lipoprotein cholesterol, and triglycerides each decreased significantly (P<0.001). Plasma thiobarbituric acid reactive substances decreased significantly (P<0.01), as did the fatty acid hydroperoxides (P<0.05), when the diet contained both chromanols. Supplementation with γ‐tocotrienol resulted in similar, though quantitatively smaller, decrements in these plasma values. Plasma α‐tocopherol concentrations were lowest in rats fed menhaden oil without either chromanol. Though plasma α‐tocopherol did not rise with γ‐tocotrienol supplementation at 50 mg/kg, γ‐tocotrienol at 100 mg/kg of ration spared plasma α‐tocopherol, which rose from 0.60±0.2 to 1.34±0.4 mg/dL (P<0.05). The highest concentration of α‐tocopherol was measured in plasma of animals fed a ration supplemented with α‐tocopherol at 500 mg/kg. In response to added collagen, the partially hydrogenated soybean oil diet without supplementary cholesterol led to reduced platelet aggregation as compared with the cholesterol‐supplemented diet. However, γ‐tocotrienol at a level of 50 mg/kg in the cholesterol‐supplemented diet did not significantly reduce platelet aggregation. Platelets from animals fed the menhaden oil diet released less adenosine triphosphate than the ones from any other diet group. The data suggest that the combination of γ‐tocotrienol and α‐tocopherol, as present in palm oil distillates, deserves further evaluation as a potential hypolipemic agent in hyperlipemic humans at atherogenic risk.
Inhibition by cardiolipins of platelet‐activating factor‐induced rabbit platelet activation
Authors: Tsoukatos Demokritos , Demopoulos Constantinos A. , Tselepis Alexandros D. , Moschidis Michael C. , Donos Andreas , Evangelou Angelos , Benveniste Jaques
Published: November 2006

Evidence is presented that cardiolipin, a naturally occurring phospholipid, inhibits the aggregatory effect of platelet‐activating factor (paf) on rabbit plateletsin vitro. Bovine heart cardiolipin was shown to inhibit the aggregation of washed rabbit platelets induced by 1×10−10 M and 2×10−10 M paf with IC50 values (doses for half‐maximal inhibition) of 8.4±0.8×10−7 M and 2.6±0.6×10−6 M, respectively. Phosphonocardiolipin was also able to inhibit platelet aggregation induced by 1× 10−10 M paf with an IC50 value of 3±1×10−7M. Both compounds, in concentrations up to 1×10−5 M, were unable to aggregate washed rabbit platelets and failed to inhibit the aggregation induced by 0.9 and 1.8 μM adenosine diphosphate or 0.2–1.0 μM arrchidonic acid. By contrast, the acetylated derivative of cardiolipin exerted an aggregatory effect on aspirin‐treated rabbit platelets in the presence of creatine phosphate/creatine phosphokinase. This aggregation was inhibited by the specific paf antagonists BN 52021 and WEB 2086. Also, platelets treated with acetyl‐cardiolipin were insensitive to the aggregatory effect of paf. Phosphatidic acid, phosphatidylglycerol,bis(dipalmitoylglycero)phosphate and their phosphono analogues were totally inactive. Similar data were obtained when platelet‐rich plasma was used instead of washed rabbit platelets. Our results support the hypothesis that the effect of cardiolipin is mediated through specific paf receptors that act on the rabbit platelet membrane.
Synthesis of deuterated cyclopropene fatty esters structurally related to palmitic and myristic acids
Authors: Gosalbo Laura , Barrot Mireia , Fabriás Gemma , Arsequell Gemma , Camps Francisco
Published: November 2006

To develop a synthesis of tritiated cyclopropene fatty acids (CPFA), compounds that should prove useful for affinity labeling of desaturases in insect pheromone biosynthetic studies, a series of novel, selectively deuterated CPFA analogues was prepared and characterized. In methyl [16‐2H]12,13‐methylene‐12‐hexadecenoate, the incorporation of deuterium was achieved by treatment of the corresponding ω‐chloro derivative with sodium borodeuteride in dimethylsulfoxide at 70°C for 24 h (67% yield) following conventional procedures. Alkylation of the tetrahydropyranyl derivative of 13‐tridecynol in the presence of lithium diisopropylamide in tetrahydrofuran at −20°C with 1‐chloro‐3‐iodopropane in hexamethylphosphoramide, followed by Jones oxidation of the crude product, yielded 16‐chloro‐12‐hexadecynoic acid (54%), which was esterified to the corresponding methyl ester by treatment with potassium carbonate and methyl iodide in dimethylformamide. Treatment of this acetylenic ester with ethyldiazoacetate in the presence of activated copper‐bronze as catalyst followed by hydrolysis in KOH solution at room temperature yielded 16‐chloro‐12,13‐(carboxymethylene)‐12‐hexadecenoic acid. This diacid was treated with excess oxalyl chloride to give the corresponding diacyl chloride, which was decarbonylated in a diethyl ether solution with zinc chloride, and the cyclopropenium ions thus formed were added at −40°C to a methanolic sodium hydroxide solution of sodium borohydride to give methyl 16‐chloro‐12,13‐methylene‐12‐hexadecenoate. Analogous procedures were followed to prepare methyl [17‐2H]10,11‐methylene‐10‐hexadecenoate, methyl [17‐2H]11,12‐methylene‐11‐hexadecenoate and methyl [17‐2H]12,13‐methylene‐12‐hexadecenoate from the corresponding diacids using sodium borodeuteride in the reduction of the cyclopropenium ions. Alternatively, methyl [2,2,3,3‐2H4]hexadecynoate, prepared by reaction of methyl 2,11‐hexadecadiynoate with magnesium in deuterated methanol at room temperature, was submitted to the above cyclopropenylation and reductive decarbonylation sequence to give methyl [2,2,3,3,17‐2H5]‐11,12‐methylene‐11‐hexadecenoate. In summary, complementary methods for the selective incorporation of one to five deuterium atoms into cyclopropene fatty acids, at different sites, in moderate to high yields have been developed. The methods should easily be applicable to the preparation of the corresponding tritiated analogues.
Synthesis of arachidonic acid metabolites by syrian hamster platelets and peritoneal cells
Authors: Surette Marc E. , Whelan Jay , Lu G. ‐P. , Kinsella John E.
Published: November 2006

In this study, the metabolism of arachidonic acid by hamster platelets and peritoneal macrophages was assessed. Peritoneal macrophages stimulatedin vitro with the calcium ionophore A23187 or stimulatedin vivo by intraperitoneal injections of opsonized zymosan produced prostaglandin E2, thromboxane B2 (TxB2) and 6‐keto‐prostaglandin F1α, as determined by radioimmuno assays. Leukotriene B4 (LTB4), and 11‐ and 15‐hydroxyeicosatetraenoic acids (HETE), which were identified by reverse‐phase highperformance liquid chromatography coupled with diode array detection, were produced by peritoneal cells stimulatedin vitro with A23187 but were not found in the peritoneal exudate followingin vivo stimulation with opsonized zymosan. Synthesis of 11‐ and 15‐HETE, but not LTB4, was inhibited by 1 μM indomethacin but not by 10 μM nordihydroguaiaretic acid, which did inhibit LTB4 synthesis. Washed hamster platelets were prepared and shown to synthesize TxB2, 12‐HETE and 12‐hydroxyheptadecatrienoic acid following stimulation with thrombin. This paper is the first to report on eicosanoid metabolism in tissues related to atherosclerosis, thrombosis and inflammation in hamsters.
Gangliosides and atherosclerosis
Authors: Prokazova N. V. , Bergelson L. D.
Published: November 2006

The ganglioside levels in atherosclerotic lesions of human aorta are considerably higher than those in unaffected areas of aorta, and atherosclerotic patients frequently have increased concentrations of serum gangliosides. The present review summarizes recent findings that suggest the possible involvement of aortic gangliosides in platelet activation and adhesion of platelets to the vessel wall. The effect of gangliosides on the structure of low density lipoproteins (LDL), on the interaction of LDL with macrophages and hepatic cells and on the LDL‐regulated biosynthesis of cholesterol is also discussed.In vitro experiments have demonstrated that a major ganglioside of the intima of atherosclerotic aorta induces rapid adhesion, aggregation and spreading of platelets. Moreover, gangliosides present in elevated amounts in the intercellular space of atherosclerotic aortic tissue modify the surface structure and stimulate aggregation of LDL. Ganglioside‐modified LDL are readily recognized and taken up by macrophages, while preincubation of LDL with low concentrations of gangliosides inhibits LDL binding to hepatic cells. Thus, ganglioside enrichment of LDL is likely to interfere with LDL clearancevia the hepatic cells. Thus, ganglioside enrichment of LDL is likely to interfere with LDL clearancevia the hepatic LDL receptor, and to stimulate binding of LDL to the scavenger receptor of macrophages. It is postulated that high ganglioside levels in the aorta and serum may be an additional risk factor in atherosclerosis.