bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trans‐ and cis‐octadecenoic acid isomers in the hump and milk lipids from Camelus dromedarius
Authors: Wolff Robert L. , Precht Dietz , Nasser Boubker , Said El Kebbaj M'hamed 
Published: November 2006

AbstractThe distribution profiles of individual trans‐ as well as cis‐18∶1 isomers from the fat prepared from the hump adipose tissue and the milk from Camelus dromedarius (the single‐humped Arabian species) are described. Gas‐liquid chromatography on two capillary columns with different polarities and lengths were used for this purpose in combination with argentation thin‐layer chromatography. A comparison of the profiles established is made with that of true ruminant fats. In the fats from the dromedarius as well as from true ruminants, the trans‐18∶1 isomers have their ethylenic bonds in all positions between Δ4 and Δ16. The prominent trans isomer is the 11–18∶1 (vaccenic) acid in all species, and the complete distribution profiles are quite similar. Concerning the cis isomers, the prominent isomer is oleic acid, followed by cis‐vaccenic acid, as in true ruminant fats. Other cis isomers encompass the Δ6–8 and the Δ12 to Δ15 isomers. Camelidae (suborder Tylopoda) and Bovidae (suborder Ruminantia) have evolved independently since the Eocene, that is for approximately 50 million years. Despite this considerable period, and the profound differences in anatomy, morphology, physiology, ecological and dietary habits between the extant species of these suborders, the rumen microflora has continued to synthesize the same trans‐ and cis‐octadecenoic acid isomers, in comparable proportions, at least as deduced from their composition profiles. We conclude that the trans‐18∶1 acid profile is not intrinsically species‐dependent, but it can be affected by the nature and the proportions of dietary unsaturated fatty acids that themselves depend on the feed, and that may be species‐specific.
Lipid remodeling in mouse liver and plasma resulting from Δ6 fatty acid desaturase inhibition
Authors: Duffin Kevin L. , Obukowicz Mark G. , Salsgiver William J. , Welsch Dean J. , Shieh Caroline , Raz Amiram , Needleman Philip 
Published: November 2006

AbstractElectrospray/tandem mass spectrometry was used to quantify lipid remodeling in mouse liver and plasma during inhibition of polyunsaturated fatty acid synthesis by the Δ6 fatty acid desaturase inhibitor, SC‐26196. SC‐26196 caused increases in linoleic acid and corresponding decreases in arachidonic acid and docosahexaenoic acid in select molecular species of phosphatidylcholine, phosphatidylethanolamine, and cholesterol esters but not in phosphatidylserine, phosphatidylinositol, or triglycerides. For linoleic acid‐, arachidonic acid‐, and docosahexaenoic acid‐containing phospholipid species, this difference was, in part, determined by the fatty acid at thesn‐1 position, namely, palmitic or stearic acid. An understanding of phospholipid remodeling mediated by Δ6 desaturase inhibition should aid in clarifying the contribution of arachidonic acid derivedvia de novosynthesis or obtained directly in the diet during inflammatory responses.
Soluble fiber and soybean protein reduce atherosclerotic lesions in guinea pigs. Sex and hormonal status determine lesion extension
Authors: Cos Edward , Ramjiganesh Tripurasundari , Roy Suheeta , Yoganathan Subbiah , Nicolosi Robert J. , Fernandez Maria Luz 
Published: November 2006

AbstractThese studies were undertaken to assess guinea pigs as potential models for early atherosclerosis development. For that purpose, male, female, and ovariectomized (to mimic menopause) guinea pigs were fed a control or a TEST diet for 12 wk. Differences between diets were the type of protein (60% casein/40% soybean vs. 100% soybean) and the type of fiber (12.5% cellulose vs. 2.5% cellulose/5% pectin/5% psyllium) for control and TEST diets, respectively. Diet had no effect on plasma cholesterol or triacylglycerol (TAG) concentrations; however, there were significant effects related to sex/hormonal status. Ovariectomized guinea pigs had higher plasma cholesterol and TAG concentrations than males or females (P<0.01). In contrast to effects on plasma lipids, hepatic cholesterol and TAG were 50% lower in the TEST groups (P<0.01) compared to controls. Low density lipoproteins (LDL) from guinea pigs fed the TEST diet had a lower number of cholesteryl ester (CE) molecules and a smaller diameter than LDL from controls. Atherosclerotic lesions were modulated by both diet (P<0.0001) and sex (P<0.0001). Guinea pigs fed the TEST diet had 25% less lesion extension whereas males had 20% larger occlusion of the arteries compared to both female and ovariectomized guinea pigs. Significant positive correlations were found between LDL CE and atherosclerotic lesions (r=0.495, P<0.05) and LDL size and fatty streak area (r=0.56, P<0.01). In addition, females fed the TEST diet had the lowest plasma and hepatic cholesterol concentrations, the smallest LDL particles, and the least atherosclerosis involvement compared to the other groups. These data indicate that dietary factors and sex/hormonal status play a role in determining plasma lipids and atherosclerosis in guinea pigs.
Incorporation of dietary linoleic and conjugated linoleic acids and related effects on eggs of laying hens
Authors: Schäfer Klaus , Männer Klaus , Sagredos Angelos , Eder Klaus , Simon Ortwin 
Published: November 2006

AbstractIn the present study, laying hens received 29 g per kg diet of a preparation containing either 70% linoleic acid (LA) or approximately the same amount of conjugated linoleic acid (CLA) in the control and experimental treatments, respectively. The CLA preparation consisted predominantly of cis‐9,trans‐11 and trans‐10,cis‐12 fatty acid isomers as free fatty acids in a ratio of 1∶1. The diets were fed for 8 wk to determine the effect of dietary CLA on quality characteristics of eggs. In addition, the fatty acid composition of liver and heart was analyzed. Performance parameters (egg weight, feed efficiency) were not significantly affected by feeding the diets supplemented with CLA. The overall amount of CLA that was incorporated into yolk was 7.95 g CLA/100 g total fatty acids, or approximately 400 mg CLA/egg. The transfer efficiency of the cis‐9,trans‐11 isomer was higher than that of the trans‐10,cis‐12 isomer; however, the transfer rate of CLA isomers into yolk and tissues was significantly lower than that of linoleic acid. Dietary CLA increased the concentration of saturated fatty acids in yolk and tissues at the expense of monounsaturated fatty acids. The proportions of myristic, palmitic, and stearic acids in yolk lipids were also changed by dietary CLA. Additionally, long‐chain polyunsaturated fatty acids (arachidonic acid and docosahexaenoic acid) were decreased without changing the balance of the n−6/n−3 ratio in egg yolk. The inclusion of CLA in layer diets altered the shape of the yolk and various egg parameters (albumen height, foam index, and yolk index). The results of this study indicate that CLA induces various changes in lipid and fatty acid metabolism of laying hens and affects quality characteristics of eggs.
Trans‐10,Cis‐12 conjugated linoleic acid reduces triglyceride content while differentially affecting peroxisome proliferator activated receptor γ2 and aP2 expression in 3T3‐L1 preadipocytes
Authors: Evans M. , Park Y. , Pariza M. , Curtis L. , Kuebler B. , McIntosh M. 
Published: November 2006

AbstractA series of experiments was conducted using 3T3‐L1 preadipocytes as the cell model to determine: (i) whether the triglyceride (TG)‐lowering effects of a crude mixture of conjugated linoleic acid (CLA) isomers were due to a specific isomer of CLA and the timing of treatment, (ii) if CLA reduced TG content by inhibiting a key regulator of adipogenesis, (iii) if CLA incorporated into either neutral lipid or phospholipid cell fractions, and (iv) whether the effects of CLA treatment were reversible. Trans‐10,cis‐12 CLA reduced TG content, whereas the cis‐9,trans‐11 isomer increased TG content compared to vehicle [bovine serum albumin (BSA)] controls. Treatment with 50 μM trans‐10,cis‐12 CLA during the entire 6 d of differentiation reduced TG content to a greater extent than treatment during either the first 3 d or last 3 d of differentiation. Trans‐10,cis‐12 CLA treatment of preadipocyte cultures for 48 h increased peroxisome proliferator activated receptor γ2 (PPARγ2) protein expression compared to cultures treated with linoleic acid (LA) or the BSA controls. CLA had no effect on adipose P2 (aP2), a fatty acid‐binding protein regulated by PPARγ2. Both the cis‐9,trans‐11 and the trans‐10,cis‐12 isomers of CLA were incorporated into neutral lipids and phospholipids. However, cis‐9,trans‐11 CLA levels were one‐ to twofold higher than trans‐10,cis‐12 CLA levels. Moreover, trans‐10,cis‐12 CLA treatment reduced cis‐11 18∶1 concentrations in both neutral lipids and phospholipids while increasing cis‐9 18∶1 and 18∶2 concentrations. Palmitoleic acid (16∶1) levels were also lower in the neutral lipid fraction of cultures treated with trans‐10,cis‐12 CLA. Supplementing trans‐10,cis‐12 CLA‐treated cultures (50 μM) with increasing levels of LA resulted in a dose‐dependent increase in TG content compared to cultures treated with 50 μM CLA alone. LA supplementation also prevented some of the morphological changes associated with trans‐10,cis‐12 CLA treatment as seen with scanning electron microscopy. Treatment with 50μM trans‐10,cis‐12 CLA for 6 d decreased PPARγ2 levels, and supplementation of CLA‐treated cultures with LA increased PPARγ2 levels compared with cultures treated with CLA alone. Taken together, these data indicate that in cultures of 3T3‐L1 preadipocytes: (i) trans‐10,cis‐12 CLA is the TG‐lowering isomer of CLA, and its effects are dependent on dose, duration of treatment, and the amount of LA in the cultures; (ii) trans‐10,cis‐12 CLA treatment alters the monounsaturated fatty acid profile of neutral‐ and phospholipids of the cultures; and (iii) although acute (2−d) trans‐10,cis‐12 CLA treatment increased PPARγ2 protein levels, chronic (6−d) treatment decreased PPARγ2 levels.
Growth modulation of low density lipoprotein receptor sterol sensitivity in cultured human fibroblasts
Authors: Tatidis Loukas , Vitols Sigurd 
Published: November 2006

AbstractSterols regulate low density lipoprotein (LDL) receptor and 3‐hydroxy‐3‐methylglutaryl coenzyme A (HMG‐CoA) reductase gene expressions by end product repression. Studies on cultured cells have shown that growing cells have a higher LDL uptake than quiescent cells and that incubation of cells with growth factors or mitogenic compounds leads to sterol‐resistant upregulation of LDL receptor gene expression. The recent finding that elevated LDL receptor activity in acute myelogenous leukemia cells was characterized by a decreased sensitivity to downregulation by sterols raises the possibility that the mechanism behind this is related to the cellular growth rate. By using cultured human fibroblasts as a model system we therefore studied whether growth modulation of sterol sensitivity takes place in normal actively growing cells. Judging from the ability of sterols (25‐hydroxycholesterol+cholesterol) to inhibit 125I‐LDL degradation, we found that the sensitivity to sterols varied markedly between cells of different densities. The lowest sensitivity to sterols and highest 125I‐LDL degradation rate were found in subconfluent cells, whereas sparse and confluent cells were the most sensitive ones. In contrast to the LDL receptor, HMG‐CoA reductase sterol sensitivity did not appear to be growth regulated. We conclude that growth‐dependent modulation of sterol sensitivity and LDL receptor activity takes place in normal human fibroblasts. Modulation of sterol sensitivity may be an important mechanism to ensure an adequate cholesterol supply in growing cells.
Regiospecific analysis of conifer seed triacylglycerols by gas‐liquid chromatography with particular emphasis on Δ5‐olefinic acids
Authors: Destaillats Frédéric , Angers Paul , Wolff Robert L. , Arul Joseph 
Published: November 2006

AbstractDibutyroyl derivatives of monoacylglycerols (DBMAG) from conifer seed oil triacylglycerols (TAG) were prepared by partial deacylation of TAG with ethylmagnesium bromide followed by diesterification with n‐butyryl chloride. The resulting mixtures were analyzed by gas‐liquid chromatography (GCL) with 65% phenylmethyl silicon open tubular fused‐silica capillary column operated under optimal conditions and separated according to both their fatty acid structures and their regiospecific distribution. Seed oils of 18 species from 5 conifer families (Pinaceae, Taxaceae, Cupressaceae, Cephalotaxaceae, and Podocarpaceae) were analyzed. The chromatograms showed a satisfactory resolution of DBMAG containing palmitic (16∶0) stearic (18∶0), taxoleic (cis‐5, cis‐9 18∶2), oleic (cis‐9 18∶1), cis‐vaccenic (cis‐11 18∶1), pinolenic (cis‐5, cis‐9, cis‐12 18∶3), linoleic (cis‐9, cis‐12 18∶2), α‐linolenic (cis‐9 cis‐12, cis‐15 18∶3), and an almost baseline resolution of DBMAG containing gondoic (cis‐11 20∶1), cis‐5, cis‐11 20∶2, sciadonic (cis‐5, cis‐11, cis‐14 20∶3), dihomolinoleic (cis‐11 cis‐14 20∶2), juniperonic (cis‐5, cis‐11, cis‐14, cis‐17 20∶4), and dihomo‐α‐linolenic (cis‐11, cis‐14, cis‐17 20∶3) acids. We have observed that results for Pinus pinaster and P. koraiensis seed oils obtained with this new simple method compared favorably with literature data established with other usual regiospecific analytical techniques. Δ5‐Olefinic acids are esterified mainly at the external positions of the glycerol backbone in all cases, in agreement with data obtained by other methodologies allowing validation of the GLC regiospecific method. To date, 45 gymnosperm species (mostly Coniferophytes) from 21 genera belonging to 9 families have been analyzed, all of them showing a definite enrichment of Δ5‐olefinic acids in the external positions of TAG. These fatty acids (FA), with one exception only, represent between‐2 and 8% of FA esterified to the internal positions. For some species, i.e., P. koraiensis and P. pinaster, this asymmetrical distribution was established by at least three analytical procedures and confirmed by stereospecific analysis of their seed TAG.
Quantitative determination of 13C‐labeled and endogenous β‐carotene, lutein, and vitamin A in human plasma
Authors: Kelm Mark A. , Flanagan Vincent P. , Pawlosky Robert J. , Novotny Janet A. , Clevidence Beverly A. , Britz Steven J. 
Published: November 2006

AbstractQuantitative procedures employing liquid‐chromatography/particle beam mass spectrometry (LC/PB‐MS) and gas chromatography‐mass spectrometry (GC‐MS) were applied to the determination of the endogenous and 13C‐labeled β‐carotene, lutein, and retinol in plasma of a subject who consumed kale (Brassica oleracea) that had been grown in a 13CO2‐enriched atmosphere. All compounds were analyzed in the negative chemical ionization (NCI) mode using methane as the moderating reagent gas. β‐Carotene and lutein were analyzed using LC/PB‐MS applying reversed‐phase high‐performance liquid chromatography (HPLC) separation procedures to resolve the analytes. The concentrations of the β‐carotene isotopomers in the plasma over a several‐week period were determined using 2H8‐β‐carotene as an internal standard. The total plasma concentrations of all trans‐lutein were quantified by HPLC analysis with a photodiode array detector using β‐apo‐8′‐carotenal as an internal standard, and the ratio of the 13C∶12C isotopomers of lutein was determined by PB‐MS. The retinol isotopomers were collected from individual HPLC fractions of the plasma extract and then analyzed as the trimethylsilyl ethers by GC‐MS in the NCI mode. The 13C‐and 12C‐retinol isotopomers were quantified using 2H4‐retinol as an internal standard. These methods demonstrate the application of highly sensitive procedures empolying NCI MS for the quantitative determination of carotenoids and vitamin A for the purpose of conducting metabolism studies of phytonutrients.
Comparison of the bligh and dyer and folch methods for total lipid determination in a broad range of marine tissue
Authors: Iverson Sara J. , Lang Shelley L. C. , Cooper Margaret H. 
Published: November 2006

AbstractFor many studies, it is important to measure the total lipid content of biological samples accurately. The Bligh and Dyer method of extraction was developed as a rapid but effective method for determining total lipid content in fish muscle. However, it is also widely used in studies measuring total lipid content of whole fish and other tissues. Although some investigators may have used modified Bligh and Dyer procedures, rarely have modifications been specified nor has their effectiveness been quantitatively evaluated. Thus, we compared this method with that of the classic. Folch extraction in determining total lipid content of fish samples ranging from 0.5 to 26.6% lipid. We performed both methods as originally specified, i.e., using the chloroform/methanol/water ratios of 1∶2∶0.8 and 2∶2∶1.8 (before and after dilution, respectively) for Bligh and Dyer and of 8∶4∶3 for Folch, and with the initial solvent/sample ratios of (3+1)∶1 (Bligh and Dyer) and 20∶1 (Folch). We also compared these with several other solvent/sample ratios. In samples containing <2% lipid, the results of the two methods did not differ. However, for samples containing <2% lipid, the Bligh and Dyer method produced significantly lower estimates of lipid content, and this underestimation increased significantly with increasing lipid content of the sample. In the highest lipid samples, lipid content was underestimated by up to 50% using the Bligh and Dyer method. However, we found a highly significant linear relationship between the two methods, which will permit the correction of reported lipid levels in samples previously analyzed using an unmodified Bligh and Dyer extraction. In the future, modifications to procedures and solvent/sample ratios should be described.
Variation in molecular species of polar lipids from Thermoplasma acidophilum depends on growth temperature
Authors: Uda Ikuko , Sugai Akihiko , Itoh Yuko H. , Itoh Toshihiro 
Published: November 2006

AbstractFive types of molecular species of C40 isoprenoid chains, having different numbers of cyclopentane rings, were detected in the ether core lipid of Thermoplasma acidophilum. The average cyclization number of the hydrocarbon chains in the lipids increased with increasing growth temperatures.
Exercise training‐induced changes in sensitivity to endothelin‐1 and aortic and cerebellum lipid profile in rats
Authors: Latorre Eduardo , Marán María , Aragonés M. Dolores , Saborido Ana , Fernandez Inmaculada , Delgado Jerónimo , Catalan R. Edgardo , Megías Alicia 
Published: November 2006

AbstractThe purpose of this work was to study whether exercise training induces changes in the lipid profile of rat aorta and nervous system and in the in vitro intrinsic responsiveness of these tissues to endothelin‐1 (ET‐1) treatment. The exercise program performed successfully produced the characteristic metabolic alterations of the trained state. Exercise training induced a large and significant increase in the levels of both aortic ethanolamine plasmalogens (PlasEtn) and glucosylceramides. In contrast, a decrease of aortic ceramide and cholesterol levels was evoked by exercise training. ET‐1 increased PlasEtn content only in sedentary animals. An exercise‐induced increase in cerebellum levels of ceramides and ceramide monohexosides was found. The cerebellum ceramide content was increased by FT‐1 more noticeably in sedentary rats than in trained animals. In contrast, cerebral cortex was observed to be largely insensitive to both exercise training and ET‐1 treatment. It was concluded that exercise training (i) induces changes in both vascular and cerebellar lipid profiles, the former being much more pronounced than the latter, and (ii) diminishes the aortic and cerebellar sensitivity to ET‐1 action.
A new cytotoxic fatty acid (5Z,9Z)‐22‐methyl‐5,9‐tetracosadienoic acid and the sterols from the far Eastern sponge Geodinella robusta
Authors: Makarieva Tatyana N. , Santalova Elena A. , Gorshkova Irina A. , Dmitrenok Andrei S. , Guzii Alla G. , Gorbach Vladimir I. , Svetashev Vassilii I. , Stonik Valentin A. 
Published: November 2006

AbstractA new fatty acid, (5Z,9Z)‐22‐methyl‐5,9‐tetracosadienoic acid (1a), and a rare fatty acid, (5Z,9Z)‐23‐methyl‐5,9‐tetracosadienoic acid (2a), the predominant constituents of the free fatty acid fraction from the lipids of the sponge Geodinella robusta, were isolated and partly separated by reversed phase high‐performance liquid chromatography, followed by multifold crystallization from MeOH to give 1a and 2a in 70% and 60% purity, respectively. These fatty acids were identified as (5Z,9Z)‐22‐and (5Z,9Z)‐23‐methyl‐5,9‐tetracosadienoic acids by nuclear magnetic resonance techniques, including distortionless enhancement by polarization transfer, heteronuclear multiple quantum connectivity, and correlation spectroscopy experiments, as well as from mass‐spectrometric data for their methyl esters, the methyl esters of their perhydro derivatives, and their pyrrolidides. Mixtures of 1a and 2a showed cytotoxic activity against mouse Ehrlich carcinoma cells and a hemolytic effect on mouse erythrocytes. The sterol fraction from the same sponge was analyzed by gas liquid chromatography mass spectrometry, and 24‐methylenecholesterol was identified as a main constituent of this fraction. The implications of the co‐occurrence of membranolytic long‐chain fatty acids and 24‐methylenecholesterol as a main membrane sterol are discussed in terms of the phenomenon of biochemical coordination.
Fast and reproducible method for the direct quantitation of adipose tissue in newborn infants
Authors: Harrington T. A. M. , Thomas E. L. , Modi N. , Frost G. , Coutts G. A. , Bell J. D. 
Published: November 2006

AbstractThe role of body fat content and distribution in infants is becoming an area of increasing interest, especially as perception of its function appears to be rapidly evolving. Although a number of methods are available to estimate body fat content in adults, many are of limited use in infants, especially in the context of regional distribution and internal depots. In this study we developed and implemented a whole‐body magnetic resonance imaging (MRI)‐based protocol that allows fast and reproducible measurements of adipose tissue content in newborn infants, with an intra‐observer variability of<2.4% and an inter‐observed variability of<7%. The percentage total body fat for this cohort of infants ranged from 13.3–22.6% (mean and standard deviation: 16.6±2.9%), which agrees closely with published data. Subcutaneous fat accounted for just over 89% of the total body fat, whereas internal fat corresponded to almost 11%, most of which was nonabdominal fat. There were no gender differences in total or regional body fat content. These results show that whole‐body MRI can be readily applied to the study of adipose tissue content and distribution in newborn infants. Furthermore, its noninvasive nature makes it an ideal method for longitudinal and interventional studies in newborn infants.