bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reaction of α‐tocopherol with alkyl and alkylperoxyl radicals of methyl linoleate
Authors: Yamauchi Ryo , Miyake Nobuyuki , Kato Koji , Ueno Yoshimitsu 
Published: November 2006

Abstractα‐Tocopherol was reacted with alkyl and alkylperoxyl radicals at 37°C in bulk phase. The lipid‐free radicals were generated by the reaction of methyl linoleate with the free radical initiator, 2,2′‐azobis(2,4‐dimethylvaleronitrile) (AMVN) under air‐insufficient conditions. The products were isolated by high‐performance liquid chromatography. Their structures were identified as 2‐(α‐tocopheroxy)‐2,4‐dimethylvaleronitrile (1), a mixture of methyl 9‐(8a‐peroxy‐α‐tocopherone)‐10(E),12(Z)‐octadecadienoate and methyl 13‐(8a‐peroxy‐α‐tocopherone)‐9(Z),11(E)‐octadecadienoate (2), methyl 9‐(α‐tocopheroxy)‐10(E),12(Z)‐octadecadienoate (3a), methyl 13‐(α‐tocopheroxy)‐9(Z),11(E)‐octadecadienoate (3b), α‐tocopherol spirodiene dimer (4) and α‐tocopherol trimer (5). When methyl linoleate containing α‐tocopherol was oxidized with AMVN under airsufficient conditions, the main products were 8a‐alkyl‐peroxy‐α‐tocopherones (2). In addition to these compounds, 6‐O‐alkyl‐α‐tocopherols (1, 3a and 3b) were formed when the reaction was carried out under air‐insufficient conditions. The results indicate that α‐tocopherol can react with both alkyl and alkylperoxyl radicals during the autoxidation of polyunsaturated lipids.
Analysis of low erucic acid turnip rapeseed oil (Brassica campestris) by negative ion chemical ionization tandem mass spectrometry. A method giving information on the fatty acid composition in positionssn‐2 andsn‐1/3 of triacylglycerols
Authors: Kallio Heikki , Currie Graeme 
Published: November 2006

AbstractA tandem mass spectrometric method is described for the rapid analysis of fatty acid combinations in mixtures of triacylglycerols. Triacylglycerols were introduced into a triple quadrupole mass spectrometervia a direct exposure probe and deprotonated using ammonia negative ion chemical ionization. Collisionally activated spectra were obtained and the resulting fragments used to identify the fatty acid constituents, and the fatty acids preferentially located at thesn‐2 position of the triacylglycerols. Fourteen major molecular weight species of purified triacylglycerols of a supercritical fluid extract of low erucic acid turnip rapeseed oil (Brassica campestris) were analyzed. The five major combinations of fatty acids comprised two thrids of the total triacylglycerols and contained oleic, linoleic and α‐linolenic acids with linoleic acid favoring thesn‐2 position.
Triacylglycerols of human milk: Rapid analysis by ammonia negative ion tandem mass spectrometry
Authors: Currie Graeme J. , Kallio Heikki 
Published: November 2006

AbstractHuman milk traicylglycerols (TAG) were analyzed by ammonia negative ion chemical ionization tandem mass spectrometry. The deprotonated molecular ions of triacylglycerols were fractionated at the first mass spectrometry (MS) stage. Twenty‐nine of the deprotonated TAG ions were further analyzed based on their collisionally activated (CA) spectra. The tandem MS analysis covered eleven major acyl carbon number fractions, two of which contained odd carbon number fatty acids. Fatty acids of 28 different molecular weights were recorded from the daughter spectra. Hexadecanoic acid was present in all CA spectra, octadecenoic acid in the CA spectra of all mono‐ and higher unsaturated TAG, and octadecadienoic acid in the CA spectra of all di‐ and higher unsaturated TAG. The major fatty acid combinations in triacylglycerols were: with 0 double bonds (DB), 12∶0/12∶0/16∶0; with 1 DB, 12∶0/16∶0/18∶1; with 2 DB, 16∶0/18∶1/18∶1; with 3 DB, 16∶0/18∶2/18∶1; with 4 DB, 18∶2/18∶1/18∶1; and with 5 DB, 18∶2/18∶2/18∶1; hexadecanoic acid typically occupied thesn‐2 position. The most abundant TAG was shown to besn‐18∶1–16∶0–18∶1, comprising about 10% of all triacylglycerols.
Hypolipidemic activity of 6‐alkoxycarbonyl‐3‐aryl‐1,3,5‐triazabicyclo[3.1.0]hexane‐2,4‐diones and 2‐alkoxycarbonyl‐5‐aryl‐1,3,5‐triazine‐4,6(1H,5H)‐diones in rodents
Authors: Izydore Robert A. , Wong O. T. , Hall Iris H. 
Published: November 2006

AbstractSignificant hypolipidemic activity was demonstrated by 6‐ethoxycarbonyl‐3‐phenyl‐1,3,5‐triazabicyclo[3.1.0]hexane‐2,4‐dione, 2‐ethoxycarbonyl‐5‐phenyl‐1,3,5‐triazine‐4,6(1H,5H)‐dione and 2‐ethoxycarbonyl‐5‐(4‐chlorophenyl)‐1,3,5‐trizine‐4,6(1H,5H)‐dione in rodents at 20 mg/kg/day. These agents lowered serum cholesterol and triglyceride levels by approximately 40% in mice after 16 d. Tissue lipids in rat liver, small intestinal mucosa, aortic wall and feces were reduced by treatment with the agents. Very low density lipoprotein (VLDL) and low density lipoprotein (LDL) cholesterol levels were reduced in the rat; high density lipoprotein (HDL) cholesterol levels were elevated after 14 d of treatment. The activities of regulatory enzymes,e.g., acetyl‐CoA synthetase, acyl‐CoA:cholesterol acyltransferase, cholesterol 7α‐hydroxylase,sn‐glycerol‐3‐phosphate acyltransferase, phosphatidylate phosphohydrolase and heparin‐induced lipoprotein lipase, involved inde novo synthesis of hepatic lipids were affected by the agents. The new compounds may represent another class of potentially useful hypolipidemic agents for the treatment of atherosclerosis since HDL cholesterol levels were increased and VLDL and LDL cholesterol levels were lowered by some of the agents.
Simultaneous determination of the main molecular species of soybean phosphatidylcholine or phosphatidylethanolamine and their corresponding hydroperoxides obtained by lipoxygenase treatment
Authors: Therond Patrice , Couturier Martine , Demelier Jean‐François , Lemonnier Frédérique 
Published: November 2006

AbstractA method for the simultaneous determination of the main molecular species of soybean phosphatidylcholine or phosphatidylethanolamine and their corresponding hydroperoxides is described. Hydroperoxides were formed by incubation of phospholipids with lipoxygenase at pH 9.2. Silicic acid column chromatography (silica Sep‐Pak column) was used to separate the phospholipids into phosphatidylcholine and phosphatidylethanolamine. A single C−18 reverse‐phase column was employed to separate the main molecular species of soybean phosphatidylcholine or phosphatidylethanolamine and their hydroperoxides by high‐performance liquid chromatography. The mobile phase consisted of 5% 10 mM ammonium acetate at pH 5 and 95% methanol. The molecular species of phosphatidylcholine and phosphatidylethanolamine were detected at 205 nm; the eluate was mixed with a chemiluminescence reagent (isoluminol and microperoxidase) and monitored by fluorometry. Under the experimental conditions used, three individual molecular species of both soybean phosphatidylethanolamine and phosphatidylcholine (18∶3/18∶2, 18∶2/18∶2 and 16∶0/18∶2), together with their corresponding hydroperoxides, were identified and quantitated.
Enantiomeric resolution of diacylglycerol derivatives by high‐performance liquid chromatography on a chiral stationary phase at low temperatures
Authors: Takagi Toru , Suzuki Toshiyuki 
Published: November 2006

AbstractSeparation of 1,2‐diacylglycerol (DG) enantiomers as their 3,5‐dinitrophenylurethane derivatives by high‐performance liquid chromatography on a chiral column (Sumichiral OA‐4100) was significantly improved at low temperature,e.g., at −30°C. A linear relationship between logarithmic retention volumes and the number of carbons and olefinic bonds of the DG enantiomers was obtained. The effects of temperature on the separation are discussed.
On‐line straight‐phase liquid chromatography/plasmaspray tandem mass spectrometry of glycerolipids
Authors: Valeur Anders , Michelsen Peter , Odham Göran 
Published: November 2006

AbstractClass separation of common glycerolipids on a diol‐phase liquid chromatography column with a gradient of the mixed solvents hexane/isopropanol/acetic acid/triethylamine is compatible with on‐line plasmaspray ionization mass spectrometry. The positive ion mass spectra exhibit prominent diacylglycerol and monoacylglycerol derived fragments, which can be utilized for quantification. In the selected‐ion monitoring mode, the detection limit for phospholipids is in the low nanogram range. The abundance of the diacylglycerol and monoacylglycerol fragments reflects the relative fatty acid composition of the phospholipid classes. Collision‐induced decomposition of diacylglycerol fragments with argon as collision gas unambiguously reveals the chain length and degree of unsaturation of the esterified fatty acids in the native lipid.
HDL3‐mediated cholesterol efflux from cultured enterocytes: The role of apoproteins A‐I and A‐II
Authors: Herold Gerhard , Hesse Uta , Wisst Frank , Fahr Carl , Fahr Milena , Rogler Gerhard , Geerling Irmlind , Stange Eduard F. 
Published: November 2006

AbstractHigh density lipoproteins (HDL) were recently demonstrated in an enterocyte model (CaCo‐2 cells) to mediate reverse cholesterol transport by retroendocytosis. The present study was carried out to define the role of the major HDL apoproteins (apo) A‐I and apo A‐II in this pathway. HDL3 was fractionated by heparin affinity chromatography into the two main fractions containing either apo A‐I only (fraction A) or both apo A‐I and apo A‐II (fraction B). In addition, liposomes were reconstituted from purified apo A‐I or apo A‐II and dimyristoyl phosphatidylcholine. The cell binding properties and cholesterol efflux potential were studied in the lipoprotein fractions and the liposomes. Both fractions exhibited similar maximal binding capacities of 4427 (A) and 5041 (B) ng/mg cell protein, but their dissociation constants differed (40.5 and 167.7 μg/mL, respectively). Fraction A induced cholesterol efflux and stimulated cholesterol synthesis more than did fraction B. Fraction A mobilized both cellular free and esterified cholesterol, whereas fraction B preferentially mobilized cholesteryl esters. Liposomes, containing either apo A‐I or apo A‐II, showed specific binding, endocytosis and endosomal transport, and were released as intact particles. Apo A‐I liposomes also mediated cholesterol efflux. In conclusion, there is evidence that the HDL3 subfractions A and B, as well as reconstituted liposomes containing either apo A‐I or apo A‐II, were specifically bound and entered a retroendocytosis pathway which was directly linked to cholesterol efflux. Quantitatively, the apo A‐I subfraction appeared to play the dominant role in normal enterocytes. The apo A‐II content of fraction B was related to the mobilization of cholesteryl esters.
Liver, serum and adipose tissue fatty acid composition in suckling zucker rats
Authors: Cleary Margot P. , Phillips Frederick C. , Morton Ruth A. 
Published: November 2006

AbstractYoung adult obese Zucker rats have altered tissue fatty acid (FA) composition. The present study was aimed at determining whether such changes were seen in either liver, serum or adipose tissue obtained from 17‐day‐old obese (fafa) rats in comparison to both homozygous (FaFa) and heterozygous (Fafa) lean rats. Body weights of obese pups (30.3 g) were significantly greater than those of homozygous lean rats (25.2 g) (P<0.05). Liver weight and lipid content were similar in all groups. Inguinal fat pad weight and lipid content were greatest in obese pups (573 mg) followed by heterozygous lean pups (303 mg); homozygous lean pups (146 mg) had the lowest values. There were no differences among the groups in hepatic FA composition in either triacylglycerol (TG) or phospholipid fractions. Serum TG was similar among the groups, while serum phospholipid was greater (P< 0.05) in obese (269 mg/dL) than in homozygous lean pups (184 mg/dL); heterozygous lean pups had an intermediate value not significantly different from either homozygous group. On a percent basis, there were no differences in FA composition in either serum lipid fraction among the three groups. There were a number of significant differences in adipose tissue FA composition between the groups on a percent basis. The adipose tissue FA composition on a percent basis reflected that of maternal milk. The results indicate that suckling obese Zucker rats do not have tissue FA profiles that are characteristic of essential FA deficiency.
Composition and structure of triacylglycerols in brown adipose tissue of rats fed fish oil
Authors: Raclot Thierry , Groscolas René , Leray Claude 
Published: November 2006

AbstractThis study examines the incorporation of highly unsaturated n−3 fatty acids (HUFA) into triacylglycerols (TAG) of brown adipose tissue (BAT), and their effect on the positional distribution of saturated (SFA) and of unsaturated (UFA) 16‐ or 18‐carbon fatty acids. To this end, rats were fed a fish oil diet for up to four weeks. The stereospecific analysis of TAG was based on generation ofsn‐1,2‐ andsn‐2,3‐acylglycerols by Grignard degradation, followed by synthesis of phosphatidic acid and specific hydrolysis with phospholipase A2. From the end of the first week of fish oil feeding, a steady‐state in the fatty acid composition of TAG in BAT was reached. HUFA concentration increased 30‐fold, mainly at the expense of n−9 UFA and of SFA. The amount of SFA decreased selectively at position 3, where these fatty acids were progressively replaced by n−3 HUFA. By contrast, the amount of UFA decreased at all positions, and their positional distribution was not affected. About 60% of HUFA was incorporated at position 3. Nearly twice as much 22∶6n−3 was incorporated into TAG than had been previously observed in white adipose tissue (WAT) [Leray, C., Raclot, T., and Groscolas, R. (1993)Lipids 28, 279–284]. At the steady‐state, the distribution of HUFA was characterized by high proportions of 22∶6n−3 and 20∶5n−3 in position 3. Moreover, in each position of TAG, a steady level was reached rapidly (within 1 wk). It is concluded that, during fish‐oil feeding, fatty acids in TAG of BAT show characteristic time‐course changes that lead to a characteristic composition and a tissue‐specific positional distribution. This suggests that adipose tissue has its own specificity in controlling the build‐up of TAG stores, which is likely to be regulated by the specificity of acylating enzymes as well as molecular rearrangements.
n‐3 fatty acids inhibit defects and fatty acid changes caused by phenytoin in early gestation in mice
Authors: High Kim A. , Kubow Stan 
Published: November 2006

AbstractOur previous work has shown that n‐3 fatty acids exert a protective effect against phenytoin‐induced cleft palate when phenytoin was administered midgestation [gestational days (GD) 12 and 13] to CD‐1 mice. The effects of dietary n‐3 fatty acids on phenytoin teratogenicity were investigated at an earlier gestational period (GD 9) to examine whether n‐3 fatty acids could exert protective action against other teratogenic effects of phenytoin apart from cleft palate. The effect of phenytoin exposure on maternal hepatic polyunsaturated fatty acid composition was also studied since Δ6 desaturase activity has been shown to be modified by pharmacological action. Female CD‐1 mice were fed a standard laboratory diet (SLD), safflower oil (SAFF) or a cod liver/linseed oil (CLO/LO)‐based diet for three weeks prior to impregnation and throughout pregnancy. Pregnant mice were administered a single i.p. dose of phenytoin on GD 9, and teratological assessments were performed on GD 19. Tissues were harvested on GD 10 for maternal hepatic phospholipid fatty acid analysis from another group of phenytoin‐treated mice. The CLO/LO and the SLD mice, as compared to the SAFF‐fed antimals, showed a reduction in total malformations and fetal growth retardation due to phenytoin. Open eye defect was the only anomaly induced by phenytoin in the CLO/LO fetuses while phenytoin produced a variety of malformations in the SAFF fetuses such as tail defects, cleft palate, open eye and absence or blockage of the ureter. Dietary n‐6/n‐3 fatty acid ratios were reflected in maternal hepatic phospholipids; however, phenytoin exposure appeared to inhibit the conversion of 18∶2n‐6 to 20∶4n‐6 in the SAFF dams only. These results indicate that the overall protective effects of dietary n‐3 fatty acids on phenytoin embryo‐toxicity are observed at an early gestational period.
Adipose monoacylglycerol: Acyl‐coenzyme a acyltransferase activity in the white‐throated sparrow (Zonotrichia albicollis): Characterization and function in a migratory bird
Authors: Mostafa Nadia , Ganesh Bhat B. , Coleman Rosalind A. 
Published: November 2006

AbstractAlthough migrating birds use stored triacylglycerol as their primary fuel for flight, they must retain sufficient stores of ω6 and ω3 fatty acids to sustain reproduction after the spring migration. Hepatic monoacylglycerol:acyl‐coenzyme A acyltransferase (EC 2.3.1.22) (MGAT) activity is associated with physiological periods in which lipolysis and β‐oxidation are prominent, and it may also play a role in the selective retention of certain essential fatty acids. Therefore, we characterized MGAT activity in adipose tissue from the whitethroated sparrow (Zonotrichia albicollis), a migratory bird. MGAT specific activity from adipose tissue and liver, respectively, was 22.2±7.27 and 0.79±0.35 nmol/min/mg of total particulate protein. Activity did not vary seasonally or between male and female birds. Specific activity increased 4.3‐fold in the presence of 75 μg of phosphatidylcholine and phosphatidylserine (1∶1, w/w). MGAT acylatedsn‐1(3)‐monooleoyglycerol,sn‐2‐monoolyelglycerol ether andsn‐1(3)‐monooleylglycerol ether at 7.5, 5.7 and 1.7%, respectively, of the rate observed withsn‐2‐monooleoylglycerol. An initial lag phase observed at low concentrations of palmitoyl‐CoA was corrected by adding 2 mM MgCl2 Mg(NO2)2 or CaCl2, suggesting a requirement for divalent cations. MGAT acylatedsn‐2‐monolinolenoylglycerol andsn‐2‐monolinoleoylglycerol in preference tosn‐2‐monooleoylglycerol. Specificity of MGAT forsn‐2‐monoacylglycerols and the probable enhanced affinity forsn‐2‐monoacylglycerols of specific acyl chains may allow selected ω6 and ω3 fatty acids to be retained within the adipocyte, white nonessential fatty acids are released for β‐oxidation in flight muscles.
Inhibition of human neutrophil leukotriene B4 synthesis in essential fatty acid deficiency: Role of leukotriene a hydrolase
Authors: Cleland Leslie G. , James Michael J. , Proudman Susanna M. , Neumann Mark A. , Gibson Robert A. 
Published: November 2006

AbstractA female subject dependent on long‐term total parenteral nutrition developed an aversion and noncompliance to a prescribed weekly lipid infusion designed to meet essential fatty acid (EFA) requirements. Fatty acids (FA) in the subject's plasma and isolated peripheral blood neurophils were analyzed in search of biochemical evidence of EFA deficiency. Neutrophil 5‐lipoxygenase metabolism was examined to assess the possible effects of EFA deficiency on neutrophil eicosanoid metabolism. EFA deficiency was confirmed by marked depletion of linoleic acid (18∶2n−6) and accumulation of eicosatrienoic acid (ETrA; 20∶3n−9) in plasma and neutrophil phospholipids. In the neutrophils, ETrA comprised 5.2% of phospholipid FA (normal reference values <0.1%), and arachidonic acid (AA; 20∶4n−6) comprised 8.6% of phospholipid FA (normal reference range 10–16%). When stimulated by A23187in vitro on three separate occasions, the subject's neutrophils displayed impaired synthesis of leukotriene B4 (LTB4), but produced normal amounts of 5‐hydroxyeicosatetraenoic acid andall‐trans isomers of LTB4 formed nonenzymatically from leukotriene A4 (LTA4). This pattern of synthesis suggested inhibition of LTA hydrolase and was also seen in neutrophils from healthy subjects by addition of exogenous ETrAin vitro. Comparative studies of the effects of ETrA and eico‐sapentaenoic acid (20∶5n−3) on neutrophilsin vitro suggested that ETrA is the more potent inhibitor. Accumulation of ETrA, rather than depletion of AA, appears principally responsible for the observed impairment of neutrophil LTB4 synthesis seen in this EFA‐deficient subject.
The effect of linoleic, arachidonic and eicosapentaenoic acid supplementation on prostacyclin production in rats
Authors: Mann Neil J. , Warrick Glenda E. , O'Dea Kerin , Knapp Howard R. , Sinclair Andrew J. 
Published: November 2006

AbstractWe examined the effect of dietary supplementation of linoleic acid (LA), arachidonic acid (AA) or eicosapentaenoic acid (EPA) to rats fed a diet low in linoleic acid onin vitro andin vivo production of prostacyclin. Male Sprague Dawley rats were fed a high‐fat diet (50% energy as fat, 1.5% linoleic acid) for two weeks. Three of the groups were then supplemented orally with either 90 mg/d of LA, AA or EPA, all as the ethyl esters, for a further two weeks while remaining on the high‐fat diet. Forty‐eight hour urine samples were collected at the end of the second and fourth weeks.In vivo prostacyclin production was determined by a stable isotope dilution, gas chromatography/mass spectrometry assay for the major urinary metabolite of prostacyclins (2,3‐dinor‐6‐keto‐PGF1α or PGI2‐M and Δ17‐2‐3‐dinor‐6‐keto‐PGF1α or PGI3‐M).In vitro prostacyclin production was determined by radioimmunoassay of the stable metabolite (6‐keto‐PGF1α) following incubation of arterial tissue. Oral supplementation with AA resulted in a rise in plasma and aorta 20∶4n−6, and increasedin vitro prostacyclin and urinary PGI2‐M production. EPA supplementation resulted in a rise in plasma and aorta 20∶5n−3 and 22∶5n−3, and a decline in plasma 20∶4n−6, but not in the aorta. In the EPA‐supplemented group, thein vitro prostacyclin and the urinary PGI3‐M increased, but urinary PGI2‐M decreased. The increase inin vitro prostacyclin production in the EPA‐supplemented rats was unexpected and without obvious explanation. Supplementation with LA had minimal effect on fatty acid composition of plasma or aorta and caused no change in prostacyclin production with either method. Thein vivo measure of prostacyclin production was positively correlated with aorta AA levels, and negatively correlated with aorta levels of EPA. There was a significant positive correlation between thein vitro production of prostacyclin and thein vivo production (as measured by the urinary prostacyclin metabolite level), despite the differences observed in the EPA‐fed group. There was a high inter‐animal variability in prostacyclin production using either method. These results indicate that dietary AA stimulates and dietary EPA reducesin vivo PGI2 production in the rat. An equivalent amount of dietary LA was without effect.