bluuebunny/crossref_metadata_2025 huggingface dataset:
Superoxide production by macrophages stimulatedin vivo with synthetic ether lipids
Authors: Schreiber Barbara M. , Layne Matthew D. , Modest Edward J.
Published: November 2006

The anticancer activity of synthetic ether lipids may depend in part upon their ability to activate cells of the monocyte/macrophage lineage. In the present study, we have sought to determine whether 1‐O‐octadecyl‐2‐O‐methyl‐rac‐glycero‐3‐phosphocholine (ET‐18‐OMe) and related ether lipids enhance superoxide production by mouse peritoneal macrophages. Ether lipids were administered intraperitoneally to C57BL/6 mice 4 d after injection with thioglycollate broth. Elicited peritoneal macrophages were harvested and purified one day later, and superoxide production was detected by measuring the superoxide dismutase inhibitable reduction of cytochrome c. Low levels of superoxide were secreted by macrophages in the absence of phorbol 12‐myristate 13‐acetate (PMA). When PMA was addedin vitro to macrophages from ET‐18‐OMe‐treated mice, these cells secreted 194.2 nmol superoxide/mg protein in comparison to 53.5 nmol superoxide/mg protein for PMA‐treated control cells. Thein vitro treatment of the macrophages with ET‐18‐OMe was not effective in stimulating superoxide secretion. Macrophages harvested from mice treated with a series of ether lipids (with and without phosphorus) were examined, and superoxide secretion was found to vary with structure. AM‐18‐OEt and CP‐7 were the most effective compounds, secreting 8.6 and 11.9 times more superoxide, respectively, than PMA‐stimulated control cells. Moreover, direct cytotoxicity of the compounds for HL60 human promyelocytic leukemic cells did not necessarily correlate with the ability of each drug to increase macrophage superoxide production.
Modification of lysine amino groups by the lipid peroxidation product 4,5(E)‐Epoxy‐2(E)‐hepteal
Authors: Zamora Rosario , Hidalgo Francisco J.
Published: November 2006

The reaction between 4,5(E)‐epoxy‐2(E)‐heptenal (EH) andl‐lysine was studied to characterize some of the compounds that may be produced when proteins react with peroxidizing lipids. A mixture of EH and lysine was incubated overnight at room temperature and then fractionated by high‐performance liquid chromatography (HPLC). Fractions were freeze‐dried and characterized by1H and13C nuclear magnetic resonance (NMR) and mass spectrometry. Four major pyrrole derivatives were obtained, namely 1‐(5′‐amino‐1′‐carboxypentyl)‐pyrrole (3), 1‐(5′‐amino‐1′‐carboxypentyl)‐2‐(1″‐hydroxypropyl)pyrrole (diastereomers 5 and 8), 1‐(5′‐amino‐5′‐carboxypentyl)pyrrole (7), and 1‐(5′‐amino‐5′‐carboxypentyl)‐2‐(1″‐hydroxypropyl)pyrrole (9). In addition, several lysine complexes were detected. A polymer (1b) that was responsible for the color and the fluorescence produced in the reaction was isolated by gel filtration chromatography from a fraction obtained by HPLC. Formation of pairs of analogs (5 and 3, 9 and 7) with and without a substituent in position 2 of the pyrrole ring suggested that the compounds were produced by the same mechanism, with the formation of the 2‐unsubstituted pyrroles corresponding to the loss of the 2‐substituent as propanal; propanal was detected by headspace capillary gas chromatography. A reaction mechanism is proposed based on the NMR data obtained when the reaction was monitored in real time in an NMR tube. The results suggest that pyrrolic amino acids 7 and 9 may be present in proteins that have been damaged by peroxidizing lipids.
Blood polyunsaturated fatty acids in patients with peroxisomal disorders. A multicenter study
Authors: Martinez Manuela , Mougan Isabel , Roig Manuel , Ballabriga Angel
Published: November 2006

The purpose of the study was to compare the polyunsaturated fatty acid (PUFA) status in patients with X‐linked adrenoleukodystrophy or adrenomyeloneuropathy (X‐ALD/AMN) with that in disorders of peroxisome biogenesis (PB). Total fatty acids and plasmalogens were quantified in plasma and red cells from 28 patients with X‐ALD/AMN, 26 patients with generalized peroxisomal disorders, and 37 controls. Total fatty acid methyl esters and plasmalogen dimethyl acetals were obtained by direct transmethylation and separated by capillary column gas chromatography. The results confirm previous findings in that docosahexaenoic acid (DHA, 22∶6n−3) was greatly decreased in both plasma and erythrocytes from patients with PB disorders. When nutritional conditions were adequate, patients with X‐ALD/AMN had normal levels of DHA. A highly significant positive correlation was found between the levels of DHA and those of plasmalogens in peroxisomal patients. As in other tissues, the parent n−6 fatty acid, linoleic acid (LA, 18∶2n−6) was significantly increased in red cells from PB patients, whereas arachidonic acid (20∶4n−6) was virtually within normal limits. In clear contrast to red cells and other tissues, arachidonate was significantly lower in plasma from PB patients. The decrease in plasma arachidonate and the high tissue levels of LA suggest a defect of Δ6 desaturase and/or Δ5 desaturase in PB patients. The n−6 fatty acids were normal in X‐ALD/AMN patients. The present data show that X‐ALD/AMN patients do not have the profound PUFA alterations that PB patients have, at least in blood.
Sponge fatty acids. 3. Occurrence of series of n−7 monoenoic andiso‐5,9 dienoic long‐chain fatty acids in the phospholipids of the marine spongeCinachyrella aff.schulzei keller
Authors: Barnathan Gilles , Doumenq Pierre , Njinkoué Jean‐Michel , Mirallès Joseph , Debitus Cécile , Lévi Claude , Komprobst Jean‐Michel
Published: November 2006

The fatty acid composition of phospholipids from the New Caledonian spongeCinachyrella aff.schulzei Keller was studied. More than 60 fatty acids were identified as methyl esters andN‐acyl pyrrolidides by gas chromatography and gas chromatography/mass spectrometry. Two isoprenoid fatty acids also were shown to be present, namely 4,8,12‐trimethyltridecanoic and 5,9,13‐trimethyltetradecanoic acids. The unusual 6‐tetradecenoic, 6‐pentadecenoic, 12‐nonadecenoic and 26‐methylheptacosanoic (iso‐28∶0) acids were found for the first time in sponge phospholipids. A series of six n−7 monoenoic long‐chain fatty acids (C23 to C28) were identified, including the rare 16‐tricosenoic, 18‐pentacosenoic and 21‐octacosenoic acids. Fifteen fatty acids possessing the typical 5,9 dienoic moiety accounted for 30% of the total fatty acid mixture. Two new fatty acids were identified, namely 5(Z)‐octacosenoic and 27‐methyl‐5(Z),9(Z)‐octacosadienoic (iso‐5,9‐29∶2). Based on gas chromatography/Fourier transform infrared experiments, the double bonds were assigned the (Z) configuration.
A simple and precise method for the routine determination of platelet‐activating factor in blood and urine
Authors: Demopoulos Constantinos A. , Andrikopoulos Nikolaos K. , Antonopoulou Smaragdi
Published: November 2006

A simple and precise method is described for the measurement of platelet‐activating factor (PAF) in blood and urine. The method involves the isolation of PAF from blood samples by two successive steps. In the first step, blood proteins are precipitated with ethanol and the “free” PAF, i.e. the PAF which is extractable with ethanol, is recovered. In the second step, “bound” PAF, i.e., PAF not extractable with ethanol, is extracted from the protein precipitate with chloroform/methanol/water. The extraction of PAF from urine samples requires only the ethanol extraction step. “Free” and “bound” PAF are then each fractionated by silicic acid column chromatography, and the methanol/water eluent containing PAF is then further fractionated by high‐performance liquid chromatography using an isocratic solvent system of acetonitrile/methanol/water. PAF is then quantitated by measuring its ability to induce platelet aggregation in an aggregometer. Application of the method to blood and urine samples from twenty‐three healthy volunteers revealed PAF levels in blood of 140–480 pg/mL (630–254.4 pg “free” PAF/mL and 64–225.6 pg “bound” PAF/mL), and of 1.2–4.0 pg PAF/mL in urine. The method overcomes various technical problems and was shown to be very precise. It should prove useful for monitoring PAF levels in various disease conditions.
Lipid composition of platelets from patients with atherosclerosis: Effect of purified eicosapentaenoic acid ethyl ester administration
Authors: Kamido Hiroshi , Matsuzawa Yuji , Tarui Seiichiro
Published: November 2006

Although eicosapentaenoic acid (EPA) has been shown to have beneficial effects in the prevention of atherosclerosis, the mechanism by which these effects occur is not entirely clear. We investigated the lipid composition of platelets in paired subjects with and without atherosclerotic disease, either hypercholesterolemic (low density lipoprotein [LDL] cholesterol [Chol]≥170 mg/dl) or normocholesterolemic (LDL‐Chol<170 mg/dl). Platelets from patients with atherosclerotic disease had a lower phosphatidylcholine (PC)/Chol ratio, when compared with those from patients without atherosclerotic disease, irrespective of LDL‐Chol levels. Eleven patients with atherosclerotic disease were treated with purified. EPA ethyl ester (1.8 g/day), and changes in lipid composition of platelets were investigated. Plasma levels of total Chol and LDL‐Chol decreased significantly after EPA administration. The phospholipid (PL)/Chol ratio and the PC/Chol ratio in platelets from patients with atherosclerotic disease increased significantly after 4–10 wk EPA treatment. The EPA content in platelets increased, while the arachidonic acid (AA) content decreased. EPA‐induced changes in the PL/Chol and the PC/Chol ratios of platelets, as well as fatty acyl chain shifts, may be related to the beneficial effects in preventing atherosclerosis, possibly by increase in the membrane fluidity.
Induction of long‐lasting hypercholesterolemia in the rat fed a cystine‐enriched diet
Authors: Sérougne C. , Mathé D. , Lutton C.
Published: November 2006

The influence of dietary excess (5%) of L‐cystine on rat plasma lipoproteins was examined. After only one week of cystine feeding, an increase in the plasma cholesterol level and a decrease in triglyceride levels were observed. The increase in cholesterol level became greater when the duration of cystine‐enriched diet increased until eight weeks (+131% after eight weeks), but no further increase occurred between 8 and 20 weeks. This change was essentially due to the progressive increase in cholesterol levels in high density lipoproteins (HDL) and in lipoproteins isolated between 1.040 and 1.063 g/ml, i.e., certain low density lipoproteins (HDL2), and containing mainly apoE‐rich lipoproteins (HDL1). The decrease in plasma triglycerides resulted from that of chylomicrons and very low density lipoproteins (VLDL). The effects observed after four or eight weeks of cystine feeding were maintained for eight weeks after replacing the cystine diet by the standard diet. Ingestion of the standard diet containing either cholestyramine (2%) or probucol (0.25%) following eight weeks of cystine feeding significantly decreased plasma cholesterol levels. It is concluded that cystine‐fed rats are a useful tool of investigation for understanding mechanisms leading to increased plasma cholesterol level and for hypocholesterolemic drug trials.
Arachidonic acid uptake by phospholipids and triacylglycerols of rat brain subcellular membranes
Authors: Lin Teng‐Nan , MacQuarrie Ronald , Sun Grace Y.
Published: November 2006

In the presence of ATP, MgCl2 and CoASH, different subcellular membrane fractions isolated from rat cerebral cortex exhibited characteristic profiles for the incorporation of [1‐14C]arachidonic acid into phospholipids and triacylglycerols. In general, uptake of label by phosphatidylcholines was higher in the synaptic membranes, and that by phosphatidylinositols was higher in the microsomes and somal plasma membranes. A substantial amount of the labeled arachidonate was also incorporated into triacylglycerols, especially in the somal plasma membranes and microsomes. Enzymes mediating the transfer of arachidonic acid to phospholipids were unstable with respect to sample storage and exposure to elevated temperatures. In contrast, the acyltransferase for triacylglycerols was more stable to these factors. Washing the membranes with bovine serum albumin resulted in an enhancement of the incorporation of label into phosphatidylinositols without affecting that of phosphatidylcholines, but the incorporation into triacylglycerols was inhibited. Treatment of synaptosomes and plasma membranes with saponin resulted in an enhancement in the labeling of phospholipids, but the labeling of triacylglycerols was inhibited. Thus, although labeled arachidonic acid was incorporated into phospholipids and triacylglycerols in brain subcellular membranes, these two types of acyltransferases exhibited different properties and responded differently to membrane perturbing agents.
Eicosanoid synthesis in 7,12‐dimethylbenz(a)anthracene‐induced mammary carcinomas in Sprague‐Dawley rats fed primrose oil, menhaden oil or corn oil diet
Authors: Abou‐El‐Ela Soad H. , Prasse Keith W. , Carroll Richard , Wade Adelbert E. , Dharwadkar Suniti , Bunce Opal R.
Published: November 2006

The comparative effects of high‐fat diets (20%, w/w) on eicosanoid synthesis during mammary tumor promotion in 7,12‐dimethylbenz(a)anthracene (DMBA)‐induced rats were studied using diets containing 20% primrose oil (PO), 20% menhaden oil (MO) or 20% corn oil (CO). Sprague‐Dawley rats fed the PO or MO diet had 21% or 24% fewer adenocarcinomas, respectively, than rats fed the CO diet. Histologically (i.e., mitotic figures, inflammatory cell infiltration and necrosis), the CO‐fed rats exhibited the highest frequency of changes within tumors. Plasma fatty acid composition was significantly altered by diet, reflecting the composition of the oils which were being fed. Only the plasma of PO‐fed rats contained detectable levels of gamma‐linolenic acid (GLA). Arachidonic acid (AA) levels were significantly higher (p<0.05) in PO‐fed than in CO‐ or MO‐fed rats. MO‐fed rats had significantly higher levels of plasma palmitic acid, while palmitoleic, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids were detected only in MO‐fed rats. As expected, linoleic acid (LA) and AA levels were lower (p<0.05) in the MO‐fed rats than in PO‐ or CO‐fed groups. The plasma of the CO‐fed rats contained significantly higher levels of oleic acid. Eicosanoid synthesis in mammary carcinomas of rats fed the 20%‐fat diets was 2–10 times higher than in mammary fat pads of control rats. The synthesis of PGE1 and LTB4 was significantly (p<0.05) higher in PO‐fed rats than in CO‐fed or MO‐fed rats, although PGE values were significantly (p<0.05) higher in CO‐fed rats than in Mo or PO groups. The synthesis of eicosanoids in both mammary fat pads and mammary carcinomas of MO‐fed rats was lower (p<0.05) than in tissues of rats fed either CO or PO diets due to less AA precursor being fed and/or to competition between n−6 and n−3 fatty acids for cyclooxygenase and lipoxygenase. The ratios of monoenoic to dienoic eicosanoids in both mammary fat pads and mammary carcinomas were higher in the PO group than in the MO or CO groups. These results suggest that inclusion of GLA (PO feeding) or EPA and DHA (MO feeding) in the diet may decrease malignancy by altering eicosanoid profiles.
Esterifications of 1‐ andrac‐2‐octanols with selected acids and acid derivatives using lipases
Authors: Sonnet Philip E. , Moore Gordon G.
Published: November 2006

Several aliphatic acids and their ethyl, isopropenyl and 2,2,2‐trichloroethyl esters were allowed to react with 1‐ and 2‐octanols catalyzed by commercial lipase preparations of porcine pancreas and the fungiCandida rugosa, Aspergillus niger andMucor miehei.

Comparisons of reactivity of the acids and esters were made in common organic solvents using the primary alcohol. Reactions of octanoic acid and its esters with 2‐octanol in hexane allowed an evaluation of stereoselectivity of the lipases with different substrates that carried the same (octanoyl) residue. A partial resolution ofrac‐2‐hexadecanol withA. niger lipase is described, and the utility of lipase selectivities (stereo, positional, fatty acid and ester) is discussed with reference to the data presented.
Interaction of rabbit lipoproteins and red blood cells with liposomes of egg yolk phospholipids
Authors: Mendez Armando J. , He Jin Lin , Huang Hui Sheng , Wen Shu Rong , Hsia S. L.
Published: November 2006

After intravenous injection of liposomes prepared from egg yolk phospholipids into rabbits, the phospholipids were readily assimilated by the lipoproteins, and there were increases in the circulating levels of cholesterol and phospholipids. The increases in cholesterol level were mainly due to increases of free cholesterol. Gradient ultracentrifugation showed that the lipoproteins decreased in density, and gel filtration chromatography showed that they increased in particle size. Upon electrophoresis, they exhibited slower mobility. Liposomes recovered from rabbits 3 hr after the injection contained free cholesterol, apolipoproteins A‐I, E and traces of C. The apolipoprotein may target the liposomes for uptake by hepatocytes. Incubation of the liposomes with rabbit red blood cell membranes in vitro caused a decrease in cholesterol content of the membranes. However, the cholesterol/phosphate ratio in red blood cells isolated from the rabbits after the injection of liposomes did not change significantly, suggesting rapid replenishment of red blood cell cholesterol in vivo, possibly by equilibration with lipoprotein cholesterol or tissue cholesterol. These results suggest that the injection of phospholipid liposomes may have an antiatherogenic effect by the removal of tissue cholesterol and enhancing hepatic disposal of cholesterol through the reverse cholesterol transport mechanism.
Docosahexaenoic acid and other dietary polyunsaturated fatty acids suppress leukotriene synthesis by mouse peritoneal macrophages
Authors: Lokesh Belur R. , Black J. Mark , German J. Bruce , Kinsella John E.
Published: November 2006

The efficacy of individual ω‐t‐3 polyunsaturated fatty acids (PUFA) in altering eicosanoid synthesis in peritoneal macrophages was studied by feeding mice for 10 days a diet containing 2 wt% fat, which included 0.5 wt% ethyl esters of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) or linolenic acid (LNA). Upon stimulation with calcium ionophore A23187, macrophages from these animals produced significantly lower amounts of leukotriene C4, leukotriene B4 and 12‐hydroxyeicosatetraenoic acid, prostaglandin E2 and 6‐keto prostaglandin F1α compared with those obtained from animals on the diets containing olive oil or safflower oil. The decrease in leukotriene synthesis was similar in the animals fed DHA, EPA or LNA diets. This depression of eicosanoids by DHA and EPA was associated with decreased levels of arachidonic acid (AA); however, LA that altered eicosanoids did not have the same effect on AA levels.
Serum fatty acid proportions are altered during the year following acute Epstein‐Barr virus infection
Authors: Williams Lowell L. , Doody Dennis M. , Horrocks Lloyd A.
Published: November 2006

Because abnormal serum fatty acid (FA) proportions had been found at three months after infectious mononucleosis (IM) in a pilot study, serum total FA profiles of 20 normal college students were measured at monthly intervals for one year following an acute Epstein‐Barr virus (EBV) infection. Below normal proportions of arachidonic acid and a reversal of the usual serum ratio of linoleic and oleic acids were maximal during the third month after acute IM. These FA abnormalities coincided with the symptom of increased physical malaise, despite apparent clinical recovery, common after IM. Persistence of low linoleic acid content beyond six months postinfection occurred in all seven students who showed continued clinical symptoms. Estimation of FA enzyme activities over the post‐IM year suggested that FA elongation function was normal, but that FA desaturation enzyme activities were lower than normal, particularly early after EBV infection. An inability of the host to normalize the serum total linoleic/oleic acid ratio may parallel a delayed recovery from EBV infection and may offer insight into its pathogenesis.
Thiophosphoester analogs of phosphatidic acids: Spectrophotometric substrates for phosphomonoesterases
Authors: Nyquist David A.
Published: November 2006

Thiophosphoester analogs of dioctanoyl and didecanoyl phosphatidic acids were synthesized for use as substrates in spectrophotometric assays. These substrates are easily dispersable in aqueous media and release thiodiacylglycerols after phosphomonoesterase catalyzed hydrolysis. The free sulfhydryl of these thiodiacylglycerols reacts with the colorimetric reagent 5,5′‐dithiobis(2‐nitrobenzoic acid) (DTNB), allowing the reaction to be followed. These analogs were shown to be good substrates for calf intestine alkaline phosphatase (highest activity at alkaline pH) and phosphomonoesterases of partially purified beef brain cytosol (highest activity at physiologic pH). Cationic amphiphilic drugs inhibit the actions of alkaline phosphatase on the dioctanoyl analog, but did not inhibit enzymatic hydrolysis ofp‐nitrophenyl phosphate. In contrast, the beef brain cytosolic fractionp‐nitrophenyl phosphate hydrolysis was mildly inhibited, and the phosphatidic acid analog hydrolysis was increased slightly. Tetramisole inhibited all enzyme activities withp‐nitrophenyl phosphate, but was inhibitory only to the alkaline‐phosphatase activity with the phosphatidic acid analog.
Increased amounts of cholesterol precursors in lipoproteins after ileal exclusion
Authors: Koivisto Pekka V. I. , Miettinen Tatu A.
Published: November 2006

Serum cholesterol precursor sterols reflect the activity of cholesterol synthesis. In this study, squalene, methyl sterol and lathosterol contents were studied in very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL) of heterozygous familial hypercholesterolemia patients without and with ileal bypass. The contents of lathosterol and all methyl sterols (lanosterol, Δ8,24‐dimethylsterol, Δ8‐dimetylsterol, Δ8‐methostenol and methostenol), but not of squalene were increased in all lipoproteins by ileal bypass. The increase in the free methyl sterols was more marked than that in the esterified ones. The percentage esterification of the methyl sterols was highest in HDL and lowest in VLDL. Lipoprotein methyl sterol contents were positively correlated with each other and with cholesterol synthesis. The methyl sterols were slightly concentrated in LDL, and squalene strongly concentrated in VLDL. It is concluded that long‐term stimulation of cholesterol synthesis increases the methyl sterols in all lipoproteins.
Incorporation of oleic acid and eicosapentaenoic acid into glycerolipids of cultured normal human fibroblasts
Authors: Miller Michael , Motevalli Mahnaz , Westphal David , Kwiterovich Peter O.
Published: November 2006

Confluent skin fibroblasts from normal humans were incubated in serum free medium with up to 100 nmole/mL eicosapentaenoic acid (EPA; bound to albumin in a 4.6∶1 ratio) and compared with cells incubated with oleic acid (OA) at similar concentrations. The rate of [14C]OA incorporation into triacylglycerol (TG) (nmol/mg/h) was approximately 5‐fold greater than that of [14C]EPA. The mass of TG formed after incubation of fibroblasts with EPA was also significantly lower than that formed with OA (43.2 ±9.3vs. 59.5±6.6 μg/mg cell protein, respectively,P=0.006). The addition of excess, unlabeled EPA reduced the rate of incorporation of [14C]OA into TG whereas unlabeled OA stimulated incorporation of [14C]EPA into TG. When the cells were preincubated with human serum basic proteins (BP I, II and III), the mass of TG formed (compared to baseline) was significantly higher with the basic proteins whether OA or EPA was studied. Only BP I significantly stimulated the mass of cell phospholipids, an effect that occurred with either OA or EPA in the medium. The results suggest that in cultured normal human fibroblasts, OA is a better substrate for TG synthesis than EPA and that this effect may be accentuated by the presence of the basis proteins.
1‐O‐alk‐1′‐enyl‐2‐acyl‐glycerophosphoethanolamine content and molecular species composition in fish brain
Authors: Bell M. V. , Dick J. R.
Published: November 2006

Ethanolamine glycerophospholipids from the brains of both trout and cod comprised 36–38% of 1‐O‐alk‐1′‐enyl‐2‐acyl‐glycerophosphoethanolamine (GPE) determined using two methods. In 1‐O‐alk‐1′‐enyl‐2‐acyl‐GPE from trout brain, the main molecular species were 18∶1a/18∶1, 18∶0a/18∶1 and 16∶0a/18∶1, which totalled 63.3%, while polyunsaturated fatty acid (PUFA) containing species totalled only 18.2%. 1‐O‐Alk‐1′‐enyl‐2‐acyl‐GPE from cod brain was much more unsaturated with PUFA containing species totalling 52.6%, of which 18∶0a/20∶5n−3, 18∶1a/20∶5n−3 and 18∶1a/22∶6n−3 were predominant. In cod 18∶1a/18∶1, 18∶0a/18∶1 and 16∶0a/18∶1 were the only other species present at over 5% each, totalling 31.8%. In both cod and trout, small amounts of species containing 22∶4n−6 were found. The results of this and earlier studies indicate that there is considerable specificity of composition at the level of molecular species between different lipid classes and subclasses.
Phospholipids inDrosophila heads: Effects of visual mutants and phototransduction manipulations
Authors: Stark William S. , Lin Teng‐Nan , Brackhahn David , Christianson J. Scott , Sun Grace Y.
Published: November 2006

A procedure was developed to label phospholipids inDrosophila heads by feeding radioactive phosphate (32Pi). High‐performance thin‐layer chromatography showed label incorporation into various phospholipids. After 24 h of feeding, major phospholipids labeled were phosphatidylethanolamine (PE), 47%; phosphatidylcholine (PC), 24%; and phosphatidylinositol (PI), 12%.Drosophila heads have virtually no sphingomyelin as compared with mammalian tissues. Notable label was in ethanolamine plasmalogen, lysophosphatidylethanolamine, lysophosphatidylcholine and lysophosphatidylinositol. Less than 1% of the total label was in phosphatidylinositol 4‐phosphate and phosphatidylinositol 4,5‐bisphosphate. Other lipids labeled included phosphatidylserine, phosphatidic acid and some unidentified lipids. A time course (3–36 h) study revealed a gradual decrease in proportion of labeled PI, an increase in proportion of labeled PC and no obvious change in labeled PE. There were no significant differences in phospholipid labeling comparing theno receptorpotential (norpA) visual mutant and wild type under lightvs. dark conditions. However, overall32P labeling was higher in the wild type fed in the light as compared to the dark and tonorpA either in light or dark. This suggests that functional vision facilitates incorporation of label. Differences in phospholipid labeling were observed between young and aged flies, particularly in lysophospholipids and poly‐PI, implicating phospholipase A2 function in recycling. Manipulations such as theouterrhabdomeresabsent andeyesabsent mutants and carotenoid deprivation failed to yield notable differences in phospholipid labeling pattern, suggesting that phospholipids important to vision may constitute only a minor portion of the total labeled pool in the head.
Stereospecificity of monoacylglycerol and diacylglycerol acyltransferases from rat intestine as determined by chiral phase high‐performance liquid chromatography
Authors: Lehner Richard , Kuksis Arnis , Itabashi Yataka
Published: November 2006

Using chiral phase high‐performance liquid chromatography of diacylglycerols, we have redetermined the ratios of 1,2‐/2,3‐diacyl‐sn‐glycerols resulting from acylation of 2‐monoacylglycerols by membrane bound and solubilized triacylglycerol systhetase of rat intestinal mucosa. With 2‐oleoyl[‐3H]glycerol as the acyl acceptor and oleoyl‐CoA as the acyl donor, 97–98% of the diacylglycerol product was 1,2(2,3)‐dioleoyl‐sn‐glycerol, 90% of which was thesn‐1,2‐and 10% thesn‐2,3‐enantiomer. The remaining diacylglycerol (less than 3%) was thesn‐1,3‐isomer. The overall yield of acylation products was 70%, of which 60% were diacylglycerols and 40% triacylglycerols. With 2‐oleylglycerol ether as the acyl acceptor and [1‐14C]oleoyl‐CoA as the acyl donor, 90% of the diradylglycerol was 1‐oleoyl‐2‐oleyl‐sn‐glycerol and 10% was the 2‐oleyl‐3‐oleoyl‐sn‐glycerol. The diradylglycerols made up 96% and the triradylglycerols 4% of the radioactive product. With 1‐palmitoyl‐sn‐glycerol as the acyl acceptor and [1‐14C]oleoyl‐CoA as the acyl donor, the predominant reaction product was 1‐palmitoyl‐3‐oleoyl‐sn‐glycerol. The 3‐palmitoyl‐sn‐glycerol was not a suitable acyl acceptor. Both 1,2‐ and 2,3‐diacyl‐sn‐glycerols were substrates for diacylglycerol acyltransferase as neither isomer was favored when 1,2‐dioleoyl‐rac‐[2‐3H]glycerol was used as the acyl acceptor. There was a marked decrease in the acylation of the 1(3)‐oleoyl‐2‐oleyl‐sn‐glycerol to the 1,3‐dioleoyl‐2‐oleyl‐sn‐glycerol. It is concluded that neither monoacylglycerol nor diacylglycerol acyltransferase exhibit absolute stereospecificity for acylglycerols as fatty acid acceptors.
Structural analysis of oxidation products of urofuran acid by hypochlorous acid
Authors: Ohki Toyokazu , Maeda Kenji , Sakakibara Jinsaku , Suzuki Eiji , Yamanaka Naoki
Published: November 2006

The oxidation of urofuran acid derivatives (1–2) by hypochlorous acid (HOCl) was investigated with the goal to possibly simplify the detection of their metabolites in biological materials. The oxidation products of 3‐carboxy‐4‐methyl‐5‐propyl‐2‐furanpropionic acid (1) were obtained as an isomeric mixture and confirmed to exist ascis (3a) andtrans (3b) isomers, based on their13C nuclear magnetic resonance (NMR) spectra. Similarly, the products of 5‐H substituted acid 2 obtained by oxidation with HOCl were identified as 4a and 4b by13C and1H NMR which indicated the presence ofcis andtrans hemiacetal hydrogens at C‐5 in a ratio of 2.11∶1. The oxidation was found to proceed in a manner different from that of the F‐acid, because of the presence of the electron withdrawing COOCH3 group at C‐3 which favored the nucleophilic attack on the carbonyl group to affordcis‐ andtrans‐2,5‐dihydroxy‐2,5‐dihydrofurans (3a−b, 4a−b).
Synthesis of phenyl substituted C18 furanoid fatty esters
Authors: Lie Ken Jie Marcel S. F. , Wong K. P.
Published: November 2006

Methyl 9,12‐epoxy‐10‐phenyl‐9,11‐octadecadienoate was prepared by acid catalyzed cyclization of methyl 9,12‐dioxo‐10‐phenyloctadecanoate, which was derived from the oxidation of methyl 9‐hydroxy‐12‐oxo‐10‐phenyloctadecanoate. The latter was exclusively obtained from methylcis‐9,10‐epoxy‐12‐oxooctadecanoate with phenyllithium in the presence of copper (I) bromide. A mixture of positional isomers, methyl 9,12‐epoxy‐10(11)‐phenyl‐9,11‐octadecadienoates, was also prepared by another route. The spectroscopic properties of the various intermediates and products were studied. The positional isomers of the phenyl substituted furanoid fatty esters were characterized by13C nuclear magnetic resonance spectrometry.
The enrichment of n−3 polyunsaturated fatty acids using aminopropyl solid phase extraction columns
Authors: Wilson Robert , James Henderson R. , Burkow Ivan C. , Sargent John R.
Published: November 2006

A rapid, simple and reliable method is described for the preparation of concentrates of methyl or ethyl esters of n−3 polyunsaturated fatty acids by solid phase extraction using aminopropyl bonded silica columns. After applying mixtures of fatty acid esters in hexane, saturated and monounsaturated fatty acid esters are preferentially eluted with hexane whereas polyunsaturated fatty acids (PUFA) can subsequently be eluted with dichloromethane. Concentrates containing 80–90% n−3 PUFA can thus be obtained using fish oil fatty acids esters as a starting material.
Release of lipoprotein lipase from cardiac myocytes by low‐molecular weight heparin
Authors: Braun J. E. A. , Severson D. L.
Published: November 2006

Incubation of cardiac myocytes from rat heart with low‐molecular weight heparin (LMWH; Mr approx. 3 kDa) for 30 min resulted in a concentration‐dependent release of lipoprotein lipase (LPL) activity into the incubation medium. The release of lipoprotein lipase from cardiac myocytes isolated from both control and diabetic rat hearts induced by LMWH (10 μg/mL) following incubation times of 10 or 30 min was significantly greater than that produced by unfractionated heparin (10 and 30 μg/mL) or decavanadate (1 mM). Since LMWH released more LPL activity into the incubation medium than unfractionated heparin following a short (10 min) incubation time, LMWH is probably more effective in displacing LPL bound to heparan sulfate proteoglycan binding sites on the cell surface of cardiac myocytes.
Effect of simvastatin on desaturase activities in liver from lean and obese zucker rats
Authors: Georges B. , Blond J. P. , Maniongui C. , Bézard J.
Published: November 2006

The effect of simvastatin, a hypocholesterolemic drug, on the biosynthesis of arachidonic acid was studied in obese and lean Zucker rats. After administration of 2 mg/kg body weight/d for 13 d, Δ6 and Δ5 desaturase activities were measured in liver microsomes at two substrate concentrations. In untreated rats, the Δ6 desaturation rate was similar in the obese and lean rats when measured at saturating substrate levels, whereas Δ5 desaturation was lower in the obese animals. Treatment with simvastatin did not change Δ6 desaturation in either phenotype but increased Δ5 desaturation in obese rats to reach the unchanged rate observed in lean animals. The changes were not reflected in the fatty acid composition of liver microsomal phospholipids when expressed as μg fatty acid/g of liver.
A simple and efficient synthesis of fatty thioacids
Authors: Shin Hyeon‐Cheol , Quinn Daniel M.
Published: November 2006

A rapid and high‐yielding two‐step synthesis of fatty thioacids from readily available staring materials has been devised. In the first step, an acid chloride is reacted with thioacetic acid at room temperature to produce a mixed thioanhydride, which in the second step is nucleophilically deacetylated with propylamine or butylamine at 5°C. Each step is complete in five minutes and proceeds in quantitative yield. The versatility of the procedure is demonstrated by the synthesis of fatty thioacids from six to sixteen carbons in length.
Characterization of a cytosolic protein in rat liver inhibiting neutral cholesteryl ester hydrolase
Authors: Shand J. H. , West D. W.
Published: November 2006

Neutral cholesteryl ester hydrolase activity (EC 3.1.1.13) present in microsomes isolated from lactating rat mammary glands was found to be inhibited by a factor (or factors) occurring in the cytosolic fraction of male rat liver. The inhibitor was heat‐labile, non‐dialyzable, destroyed by proteolysis, and was stable following preparation of an acetone/diethyl ether powder of the cytosolic fraction. The protein also inhibited the activity of hormone‐sensitive lipase (HSL) (from bovine adipose tissue) and esterase fromCandida cylindracea, but seemed to be more active against the neutral hydrolase found in rat liver microsomes. For the mammary gland microsomal cholesteryl ester hydrolase, the extent of the inhibitory effect was dependent on the concentration of the cytosolic protein, 50% inhibition being achieved by about 100 μg of cytosolic protein, and on the method of initiating the enzyme assay. Kinetic analysis indicated that, under circumstances where the reaction was initiated by the addition of substrate, the inhibition was characterized as “uncompetitive”. When an inhibitor/substrate complex was allowed to form in the absence of enzyme, an element of “competitive” inhibition was introduced into the reaction. Food withdrawal reducted the activity of the inhibitor in live by 56%, but activity was fully restored by short‐term re‐feeding. In contrast, feeding a diet high in fat led to a 34% increase in activity. The present findings suggest that the inhibitory factor(s) may be involved in the regulation of the hydrolysis of cholesteryl esters in the liver and also in other cell types.
The inhibition of neutral cholesteryl ester hydrolase by a cytosolic protein factor in female rat liver: The influence of varying hormonal and nutritional conditions on the inhibitory activity
Authors: Shand J. H. , West D. W.
Published: November 2006

A cytosolic protein, that is inhibitory to neutral cholesteryl ester hydrolase, has been investigated in the livers of female rats using microsomes isolated from the mammary gland of lactating rats as an enzyme source. To facilitate comparisons, inhibitory activity is expressed in terms of the amount (μg) of cytosolic protein required to reduce esterase activity by 50% and is compared to the hepatic content of both cholesterol and cholesteryl esters. The experiments revealed a sexual difference in the level of inhibitory activity, with the livers of both suckling and mature male animals containing less of the material than the corresponding females. Alterations in the physiological status of the females, such as pregnancy and lactation, led to a decrease in the activity of the protein. This was reversed by blocking lactation with a combination of an antiserum to rat growth hormone and the anti‐prolactin drug, bromcoriptine, but not by premature weaning of the animals. Food withdrawal for 24 hr also had the effect of increasing inhibitory activity. In general the cholesteryl ester content of the livers correlated with the level of inhibitory activity. Thus the activity of the cytosolic inhibitor of neutral cholesteryl ester hydrolase responded to changes in both the hormonal and the nutritional status of the female animal. It is suggested that the presence of the greater cholesteryl ester hydrolase inhibitory activity in the female liver may help to explain the lower risk of coronary heart disease in premenopausal females by facilitating increased hepatic storage of the sterol in the form of the ester.
Cholestane as a digestibility marker in the absorption of polyunsaturated fatty acid ethyl esters in Atlantic salmon
Authors: Sigurgisladottir Sjofn , Lall Santosh P. , Parrish Christopher C. , Ackman Robert G.
Published: November 2006

Salmonid fish require long‐chain n−3 fatty acids in their diet. The digestibility of different chemical forms of fish oil fatty acids, fed as triacylglycerols, free fatty acids or ethyl esters, was examined in 300 g farmed Atlantic salmon (Salmo salar) using cholestane as an indicator of fat absorptionin lieu of the chromium oxide (Cr2O3) which is commonly used as a marker in digestibility studies. It was established that the two digestibility markers gave similar results. Conveniently, cholestane does not require a separate analysis if fatty acids are to be determined by appropriate gas‐liquid chromatography. The long‐chain polyunsaturated fatty acids were particularly well absorbed, the apparent digestibility being 90–98% when feeding triacylglycerols or free fatty acids. However, the digestibility of monounsaturated fatty acids (75–94%) was lower, and lower still for saturated fatty acids (50–80%). Ethyl esters of fatty acids were significantly less well absorbed (P<0.05) than were the corresponding fatty acids in free acid or triacylglycerol form. Irrespective of dietary fat type, only free fatty acids were identified in feces, indicating total hydrolysis of triacylglycerols and ethyl esters.
Comparison of the effects of dietary fish oils with different n−3 polyunsaturated fatty acid compositions on plasma and liver lipids in rats
Authors: Banerjee I. , Saha S. , Dutta J.
Published: November 2006

The effects of dietary fish oils with different n−3 polyunsaturated fatty acid compositions on plasma lipid profiles in rats have been studied. Forty‐eight male rats, previously maintained on a cholesterol‐free diet for 15 days, were fed for 60 days with diets supplemented with 10% fat of either marine hilsa fish (Hilsa ilisa, family clupeidae) or fresh‐water chital fish (Notopterus chitala, family notopteridae). The diets had similar levels of total saturated (35–41%), monounsaturated (43–47%) and n−3 polyunsaturated (9–10%) fatty acids. Cholesterol contents of the diets were adjusted to 0.85%; γ‐linolenic acid (3.3%) in chital oil and eicosapentaenoic acid (4.9%) in hilsa oil diets were the major n−3 contributors. The percentage of eicosapentaenoic acid in the chital oil diet was 0.57 times that of the hilsa oil diet, but the eicosapentaenoic (EPA) to arachidonic acid (AA) ratio in the latter (4.08) was 3.2 times that of the former (1.27). Sixty days of hilsa oil diet feeding decreased the levels of cholesterol (53.3±2.9 to 50.0±1.1 mg/dL), triacylglycerol (75.7±3.8 to 64.3±2.6 mg/dL) and phospholipid (55.8±1.5 to 51.7±3.1 mg/dL) in rat plasma. Similar treatment with chital oil diet elevated the plasma cholesterol level (53.3±2.9 to 62.3±7.6 mg/dL) while triacylglycerol and phospholipid contents remained unaltered. Both the dietary treatments decreased the levels of linoleic and arachidonic acids in liver but only under the hilsa oil diet did the eicosapentaenoic acid percentage increase markedly (0.8±0.06% to 5.5±0.06%) at the expense of arachidonic acid. This study strongly suggests that the hypolipidemic effect depends on the composition of the n−3 polyunsaturated fatty acids rather than on the total n−3 polyunsaturated fatty acid content of the dietary fish oil.
Characterization of triacylglycerols in the seeds ofAquilegia vulgaris by chromatographic and mass spectrometric methods
Authors: Demirbüker Mustafa , Blomberg Lars G. , Olsson N. Urban , Bergqvist Magnus , Herslöf Bengt G. , Alvarado Jacobs Fernando
Published: November 2006

A combination of analytical techniques is generally necessary to properly characterize complex lipid materials. Chromatographic separation in conjunction with spectroscopic characterization was utilized for the analysis of the triacylglycerols in the seeds ofAquilegia vulgaris. Reversed‐phase high‐performance liquid chromatography (HPLC), micropacked argentation supercritical fluid chromatography (SFC), and combinations of the two techniques were used. The fatty acid profile was determined by gas chromatography/mass spectrometry of the picolinyl esters and by gas chromatography/flame‐ionization detection of the methyl esters. The major components were also identified by direct inlet mass spectrometry. The excellent selectivity of packed fused silica argentation SFC for the separation of triacylglycerols was demonstrated.
Triester glycerothiophosphates of cholecalciferol (vitamin D3)
Authors: Stamatov Stephan D. , Gronowitz Salo
Published: November 2006

Tris(N,N‐dimethyl)amide of phosphorous acid activated by addition of iodine at an optimal molar ratio of 1.05∶0.05 was used as a phosphorylating reagent to synthesize cholecalciferyl‐3‐O‐(1‐2‐isopropylidene‐rac‐glycero‐3‐O‐)‐thiophosphate and cholecalciferyl‐3‐O‐(1,2‐dipalmitoyl‐rac‐glycero‐3‐O‐)thiophosphate of methyl alcohol, 2‐dimethylaminoethanol, 3‐dimethylamino‐1‐propanol and 1,2‐isopropylidene‐rac‐glycerol in a “one‐pot procedure” in overall yields of 60–80%. Activation of the reaction with an equimolar mixture of imidazoeland carbon disulfide at the triester formation step permits selective phosphorylation at room temperature. The compounds synthesized represent new triester phospholipid model compounds in which (in addition to glycerol and another requisite alcohol) a steroid and an element other than oxygen are bond to phosphorus.
A colorimetric assay for measuring cell‐free and cell‐bound cholesterol oxidase
Authors: Kreit Joseph , Lefebvre Gérard , Elhichami Abdelhak , Germain Pierre , Saghi Mohamed
Published: November 2006

Cholesterol oxidase (cholesterol:oxygen oxidoreductase, EC 1.1.3.6) catalyzes the conversion of sterol Δ5‐3β‐alcohol to the corresponding Δ4‐3‐ketone with the reduction of oxygen to hydrogen peroxide.Rhodococcus species GK 1, a soil isolated microbe, produces an extracellular and a membrane‐bound cholesterol oxidase; the latter is bound to the outer surface of the microbial cell membrane. A simple and sensitive assay is described to measure the two enzyme types; no enzyme extraction is needed for measuring the membrane‐bound cholesterol oxidase. In this assay, hydrogen peroxide is reduced by the chromogen 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonate) (ABTS) in the presence of horseradish peroxidase, and the increased absorbance is followed continuously at 600 nm (εm = 1.82×104 M−1·cm−1 at pH 7.0 and 30°C). The standardized assay medium contained 46.9 mM sodium‐potassium phosphate buffer pH 7.0, 0.16% Triton X‐100, 312.5 μM ABTS, 50 μg peroxidase (12.5 units at 25°C), 6.25% isopropanol, 306.3 μM cholesterol or other sterols (kept in solution with isopropanol), and cholesterol oxidase. Oxidation of one molecule of cholesterol by cholesterol oxidase gives one molecule of hydrogen peroxide which reacts with two molecules of ABTS. The method is reproducible and the results correlate well with those obtained by measuring the absorbance of Δ4‐cholest‐3‐one at 240 nm (εm = 1.40×104 M−1·cm−1 at pH 7.0 and 30°C) and by the method of Allainet al. (Clin. Chem. 20, 470–475, 1974). In terms of efficiency, simplicity, and time saved, this coupled assay is expected to be a useful method for monitoring microbial production of cholesterol oxidase on an industrial scale, and for determining cholesterol or other sterols in biological fluids.
The effect of amino acids on choline uptake and phosphatidylcholine biosynthesis in mammalian hearts
Authors: Chan Monroe , Karmin O , Man Adrian S. , Choy Patrick C.
Published: November 2006

The uptake of choline in mammalian hearts in the presence of amino acids was examined. Isolated hamster, guinea pig, rat and rabbit hearts were perfused with labeled choline in the presence and absence of amino acids. Neutral amino acids enhanced choline uptake in the hamster heart, but not in the guinea pig, rat and rabbit hearts. Phosphatidylcholine biosynthesis in these hearts was not affected by the presence of amino acids. Choline uptake in the hamster myocytes was also enhanced by neutral amino acid. The enhancement of choline uptake suggests a direct interaction between the amino acid and the transport of choline into the myocardiac cells. The different responses in choline uptake to neutral amino acids indicate that the regulation of choline uptake in the hearts may be different between mammalian species.
Changes in lipid content, fatty acid composition and lipoprotein lipase activity in dry goat omental adipose tissue according to tissue site
Authors: Bas P. , Gallouin F. , Morand‐Fehr P.
Published: November 2006

Water and lipid contents, fatty acid distribution, and lipoprotein lipase activity were determined in 11 samples taken from theOmentum Majus of five dry Alpine goats. Samples were chosen to standardize sampling sites using geometric guide marks representative of different adipose tissue sites. Sample location explained between 20% and 30% of the total variance in water and lipid contents and in lipoprotein lipase activity, and from 5.5% to 45.4% of the total variance in fatty acid distribution. Increased sample thickness was associated with an increase in lipid content and in saturated fatty acid percentages. Samples taken in proximity of the omentum tissue attached to the rumen and abomasum had the highest content. We furthermore found that the levels of 18∶2n−6, 18∶1n−7, and of branched chain fatty acids were high close to a pila of the rumen which also corresponded to high lipoprotein lipase activity. Concomitant high levels of 16∶1n−7, 17∶1n−8, and 18∶1n−9 may reflect high levels of Δ9 desaturase activity.