bluuebunny/crossref_metadata_2025_split huggingface dataset:
Serum cholesterol predictive equations with special emphasis on Trans and saturated fatty acids. An analysis from designed controlled studies
Authors: Müller Hanne , Kirkhus Bente , Pedersen Jan I. 
Published: November 2006

AbstractThe effects of dietary trans fatty acids on serum total and low density lipoprotein (LDL) cholesterol have been evaluated by incorporating trans fatty acids into predictive equations and comparing their effects with the effects of the individual saturated fatty acids 12∶0, 14∶0, and 16∶0. Trans fatty acids from partially hydrogenated soybean oil (TRANS V) and fish oil (TRANS F) were included in previously published equations by constrained regression analysis, allowing slight adjustments of existing coefficients. Prior knowledge about the signs and ordering of the regression coefficients was explicitly incorporated into the regression modeling by adding lower and upper bounds to the coefficients. The amounts of oleic acid (18∶1) and polyunsaturated fatty acids (18∶2, 18∶3) were not sufficiently varied in the studies, and the respective regression coefficients were therefore set equal to those found by Yu et al. [Yu, S., Derr, J., Etherton, T.D., and Kris‐Etherton, P.M. (1995) Plasma Cholesterol‐Predictive Equations Demonstrate That Stearic Acid Is Neutral and Monounsaturated Fatty Acids Are Hypocholesterolemic, Am. J. Clin. Nutr. 61, 1129–1139]. Stearic acid (18∶0), considered to be neutral, was not included in the equations. The regression analyses were based on results from four controlled dietary studies with a total of 95 participants and including 10 diets differing in fatty acid composition and with 30–38% of energy (E%) as fat. The analyses resulted in the following equations, where the change in cholesterol is expressed in mmol/L and the change in intake of fatty acids is expressed in E%: Δ Total cholesterol=0.01 Δ(12∶0)+0.12 Δ(14∶0)+0.057 Δ(16∶0)+0.039 Δ(TRANS F)+0.031 Δ(TRANS V)−0.0044 Δ(18∶1)−0.017 Δ(18∶2, 18∶3) and ΔLDL cholesterol =0.01 Δ(12∶0)+0.071 Δ(14∶0)+0.047 Δ(16∶0)+0.043 Δ(TRANS F)+0.025 Δ(TRANS V)−0.0044 Δ(18∶1)−0.017 Δ(18∶2, 18∶3). The regression analyses confirm previous findings that 14∶0 is the most hypercholesterolemic fatty acid and indicate that trans fatty acids are less hypercholesterolemic than the saturated fatty acids 14∶0 and 16∶0. TRANS F may be slightly more hypercholesterolemic than TRANS V or there may be other hypercholesterolemic fatty acids in partially hydrogenated fish oil than those included in the equations. The test set used for validation consisted of 22 data points from seven recently published dietary studies. The equation for total cholesterol showed good prediction ability with a correlation coefficient of 0.981 between observed and predicted values. The equation has been used by the Norwegian food industry in reformulating margarines into more healthful products with reduced content of cholesterol‐raising fatty acids.
Comparative bioavailability of dietary α‐linolenic and docosahexaenoic acids in the growing rat
Authors: Poumès‐Ballihaut Carine , Langelier Bénédicte , Houlier Françoise , Alessandri Jean‐Marc , Durand Georges , Latge Christian , Guesnet Philippe 
Published: November 2006

AbstractAnimal and human studies have indicated that developing mammals fed only α‐linolenic acid (18∶3n−3) have lower docosahexaenoic acid (22∶6n−3) content in brain and tissue phospholipids when compared with mammals fed 18∶3n−3 plus 22∶6n−3. The aim of this study was to test the hypothesis that low bioavailability of dietary 18∶−3 to be converted to 22∶6n−3 could partly explain this difference in fatty acid accretion. For that purpose, we determined the partitioning of dietary 18∶3n−3 and 22∶6n−3 between total n−3 fatty acid body accumulation, excretion, and disappearance (difference between the intake and the sum of total n−3 fatty acids accumulated and excreted). This was assessed using the quantitative method of whole‐body fatty acid balance in growing rats fed the same amount of a 5% fat diet supplying either 18∶3n−3 or 22∶6n−3 at a level of 0.45% of dietary energy (i.e., 200 mg/100 g diet). We found that 58.9% of the total amount of 18∶3n−3 ingested disappeared, 0.4% was excreted in feces, 21.2% accumulated as 18∶3n−3 (50% in total fats and 46% in the carcass‐skin compartment), and 17.2% accumulated as long‐chain derivatives (14% as 22∶6n−3 and 3.2% as 20∶5n−3+22∶5n−3). Similar results were obtained from the docosahexaenoate balance (as % of the total amount ingested): disappearance, 64.5%; excretion, 0.5%; total accumulation, 35% with 30.1% as 22∶6n−3. Thus, rats fed docosahexaenoate accumulated a twofold higher amount of 22∶6n−3, which was mainly deposited in the carcass‐skin compartment (68%). Similar proportions of disappearance of dietary 18∶−3 and 22∶6n−3 lead us to speculate that these two n−3 polyunsaturated fatty acids were β‐oxidized in the same amount.
Evidence for specific ceramidase present in the intestinal contents of rats and humans
Authors: Duan Rui‐Dong , Cheng Yajun , Yang Liping , Ohlsson Lena , Nilsson Åke 
Published: November 2006

AbstractA neutral ceramidase activity stimulated by bile salt was previously identified in the intestinal content. Recently, bile salt stimulated lipase (BSSL) was found to have ceramidase activity. It is unknown whether the ceramidase activity previously found is attributable to BSSL. To address this question, we compared the behaviors of high quaternary aminoethyl (HQ) anion exchange chromatography, the distributions, the stability, and the responses to lipase inhibitor between ceramidase and pancreatic BSSL. The proteins from whole small intestinal contents of humans and rats were precipitated by acetone and dissolved in 20 mM Tris buffer pH 8.2. These proteins had neutral ceramidase activity but not BSSL activity against p‐nitrophenyl acetate. When the proteins were subject to HQ chromatography, two peaks of ceramidase activity were identified, which had acid and neutral pH optima, respectively. Neither of them had BSSL activity against p‐nitrophenyl acetate. Western blot using BSSL antiserum failed to identify BSSL protein in the fractions, with high neutral ceramidase activity. In rat intestinal tract, pancreatic BSSL activity was high in the duodenum and declined rapidly in the small intestine, whereas neutral ceramidase activity was low in the duodenum and maintained a high level until the distal part of the small intestine. In addition, orlistat, the inhibitor of lipase, abolished human BSSL activity against p‐nitrophenyl acetate and slightly reduced its activity against ceramide but had no inhibitory effect on ceramidase activity isolated by HQ chromatography. In conclusion, we provide the evidence for a specific ceramidase other than pancreatic BSSL present in the intestinal content. The enzyme may play important roles in digestion of dietary sphingolipids.
Incubation of lipid emulsions with plasma lipoproteins modifies the fluidity of each particle
Authors: Chanson Nathalie F. , Lontie Jean‐François , Carpentier Yvon A. , Motta Claude 
Published: November 2006

AbstractLipid emulsions (LE) contain triglyceride (TG)‐rich particles (TGRP) and phospholipid‐rich particles (PLRP). Various lipid and protein exchanges take place during in vitro incubations of LE with lipoproteins. These composition changes affect physical properties of particles. The aim of this study was to determine the role of different LE particles and the effect of TG composition on physical modifications. Low density lipoproteins (LDL: 1.025<d<1.040 g/mL) or high density lipoproteins (HDL: 1.085<d<1.150 g/mL) were incubated with the following four LE or their TGRP or PLRP, which were manufactured with the same phospholipid emulsifier: long‐chain triglycerides (LCT): 100% soybean oil; medium‐chain triglycerides (MCT)/LCT (MCT/LCT, 5∶5, w/w); FO (100% fish oil); and MLF541 (MCT/LCT/FO, 5∶4∶1, by wt). After incubation, modified LE particles and lipoproteins were analyzed by fluorescence polarization. Observed physical modifications were significant in emulsion particles (ordering effect) but not in lipoporteins and also were significant for TG composition effect. Since intact emulsion contained a large excess of TGRP over PLRP, it is not surprising that intact emulsion had the same behavior as TGRP alone, and that PLRP had the same physical characteristics as lipoproteins. TG loss and cholesterol and protein acquisitions by emulsion particles rigidify their envelope. The two emulsions containing FO were less ordered after incubation. In conclusion, incubation of LE with lipoproteins changes physical properties of each kind of particle, and TG composition of the emulsion affects emulsion particle changes but has no effect on LDL and HDL. These order modifications induce more effective exchanges between LE particles and lipoproteins and modify their metabolism; HDL changes may increase the reverse cholesterol transport.
Comparative studies on individual isomeric 18∶1 acids in cow, goat, and ewe milk fats by low‐temperature high‐resolution capillary gas‐liquid chromatography
Authors: Precht Dietz , Molkentin Joachim , Destaillats Frédéric , Wolff Robert L. 
Published: November 2006

AbstractThe trans‐ as well as the cis‐18∶1 isomer profiles were established in cow, goat, and ewe cheese fats, with the assumption that these are representative of the corresponding milks. Argentation thin‐layer chromatography was combined with low‐temperature high‐resolution gas‐liquid chromatography on 100‐m highly polar capillary columns, thus adding precision to earlier data for these species. Despite differences in the absolute content of trans‐18∶1 isomers between species, the relative profiles were essentially similar. Except for the minor trans Δ6–Δ8 group, all trans‐18∶1 isomers with their ethylenic bonds between positions Δ4 and Δ16 (including the resolved critical pair Δ13/Δ14) were separated and quantitated individually. As expected, vaccenic (trans Δ9−18∶1) acid was the main isomer, accounting for as much as 37 to 50% of the total fraction. It was observed that the goat trans‐18∶1 isomer profile was usually rather close to that of cows in winter (barn feeding), whereas that of the ewe shows a seasonal dependence. The trans‐18∶1 profile of ewe milk fats from this study resembles that of cows in the transition period between winter and summer (pasture) feeding. Regarding the cis‐18∶1 acid fraction, two isomers (oleic and cis‐vaccenic acids) accounted for ca. 97% of that fraction for the three species, with the cis‐Δ12 isomer ranked third. The analytical procedure employed here appears a convenient alternative to oxidative‐based procedures (generally ozonolysis), taking less time and alleviating some draw‐backs of the latter procedure.
Enrichment of eggs with n−3 polyunsaturated fatty acids: Effects of vitamin E supplementation
Authors: Grune Tilman , Krämer Klaus , Hoppe Peter P. , Siems Werner 
Published: November 2006

AbstractEggs enriched with n−3 polyunsaturated fatty acids (PUFA) could contribute to dietary intake of these healthful fatty acids (FA). Because n−3 PUFA are highly susceptible to peroxidation, a first part of the study with Leghorn laying hens was carried out to investigate the influence of different levels of fish oil (0, 0.7, 1.4, 2.8, or 5.6%, respectively) in the diet on n−3 PUFA, cholesterol, vitamin E, and lipid peroxidation product contents in eggs. Addition of fish oil to a complete diet based on wheat, rye, tapioca, and soybean constituents containing 11 IU vitamin E/kg resulted in increased n−3 PUFA content in egg yolk, mainly due to accumulation of docosahexaenoic acid. Cholesterol was not altered up to 2.8% fish oil in the diet. The vitamin E content of the yolk was insufficient for the protection of PUFA from peroxidation. Addition of up to 2.8% fish oil to laying hen diets increased the n−3 PUFA content of yolks with a concomitant imbalance between vitamin E and PUFA, leading to increased levels of cytotoxic aldehydic lipid peroxidation products such as malondialdehyde (MDA). In a second part of the studies, the balance between vitamin E, PUFA, and lipid peroxidation was analyzed during the period of storage of n−3 PUFA‐enriched eggs produced after feeding the laying hens with 1.5% fish oil diets with different concentrations of vitamin E (0, 5, 10, 20, 40, 80, 160 IU/kg). Storage of eggs resulted in a marked loss of vitamin E in yolk. In stored eggs, the cytotoxic lipid peroxidation products MDA, 4‐hydroxynonenal, and 4‐hydroxyhexenal were reduced in response to vitamin E supplementation. To prevent the increase of cytotoxic aldehydic lipid peroxidation during production and storage of n−3 PUFA‐enriched eggs, a high vitamin E supplementation with at least 80 IU vitamin E/kg is needed.
Diferuloylputrescine and p‐coumaroyl‐feruloylputrescine, abundant polyamine conjugates in lipid extracts of maize kernels
Authors: Moreau Robert A. , Nuñez Alberto , Singh Vijay 
Published: November 2006

AbstractExtraction of corn bran or corn fiber with polar solvents such as methylene chloride, ethanol or chloroform/methanol yielded common lipids and two unknown high‐performance liquid chromatography (HPLC) peaks, each with an ultraviolet absorbance maximum at 320 nm. HPLC‐mass spectrometry revealed that the unknowns were diferuloylputrescine (DFP) and p‐coumaroyl‐feruloylputrescine (CFP). When compared to extracts of corn fiber (a pericarp‐enriched fraction from the wet milling of corn), comparable extracts of corn bran (a pericarp‐ enriched fraction from the dry milling of corn) yielded three‐ to eightfold higher levels of DFP and CFP. Extraction of corn bran or fiber with an accelerated solvent extractor revealed that elevated temperatures greatly enhanced the extraction of DFP and CFP by methylene chloride and ethanol. “Corn bran oil,” prepared by extraction of corn bran with hot methylene chloride, contained 14 wt% DFP and 3 wt% CFP. However, when hexane was used as a solvent, accelerated solvent extraction of the corn bran or fiber did not extract any DFP or CFP. Extraction of wheat bran or psyllium hulls with hot methylene chloride did not yield any detectable DFP or CFP. Because it has been suggested that polyamine conjugates such as DFP and CFP may function as natural pesticides, a rapid method was developed to purify them so that their biological activity could be evaluated.
Characterization of lipoxygenase oxidation products by high‐performance liquid chromatography with electron impact‐mass spectrometric detection
Authors: Nuñez Alberto , Foglia Thomas A. , Piazza George J. 
Published: November 2006

AbstractLipoxygenase (LOX) is an enzyme that oxygenates polyunsaturated fatty acids to their corresponding hydroperoxy derivatives. For example LOX found in plants produce the corresponding 13‐ and 9‐hydroperoxide derivatives of linoleic acid (13‐HPOD and 9‐HPOD). Identification of the HPOD products is usually accomplished by using gas chromatography with mass spectrometric (MS) detection, which requires extensive derivatization of the thermally unstable hydroperoxy group. Here we report a high‐performance liquid chromatographic method in combination with electron impact (EI)‐MS detection that separates and characterizes the HPOD isomers generated by soybean LOX type I oxygenation of linoleic (LA) and linolenic acids as well as HPOD products produced by photosensitized oxidation of LA. The method does not required derivatization of the hydroxyperoxide group, and location of its position can be determined by the EI‐MS fragmentation pattern. The method has been used for the analysis of HPOD produced by action of partially purified LOX from the micro‐alga Chlorella pyrenoidosa on LA. The study suggests the presence of two LOX isozymes in the micro‐alga that oxygenate LA to its 13‐HPOD and 9‐HPOD derivatives. Moreover, the 9‐LOX isozyme under anaerobic conditions cleaves 13‐HPOD to 13‐oxo‐tridecadienoic acid and pentane but does not cleave 9‐HPOD.
Mixed‐chain phospholipids: Structures and chain‐melting behavior
Authors: Huang Ching‐hsien 
Published: November 2006

AbstractIt has long been established that diacyl phospholipids isolated from animal cell membranes are predominantly of a mixed‐chain variety, meaning that the sn‐1 and sn‐2 acyl chains are saturated and unsaturated acyl chains, respectively. In general, monoenoic and dienoic acids are found in the sn‐2 acyl chain of phosphatidylcholine (PtdCho), whereas polyenoic acids are in phosphatidylethanolamine (PtdEth). These unsaturated chains contain only cis‐double bonds, which are always methylene‐interrupted. In recent years, the structures and the chain‐melting behavior of mixed‐chain PtdCho and PtdEth have been systematically studied in this laboratory. Specifically, we have examined the effects of chain unsaturation of the sn‐2 acyl chain on the phase transition temperature (Tm) of many PtdCho and PtdEth by high‐resolution differential scanning calorimetry (DSC). The Tm values, for instance, obtained from all‐unsaturated mixed‐chain PtdEth derived from a common precursor can be grouped together according to their chemical formula to form a Tm‐diagram. Hence, all the Tm values can be compared simply, systematically, and simultaneously using the Tm‐diagram. In addition, the energy‐minimized structures of mixed‐chain phospholipids containing different numbers/positions of methylene‐interruped cis‐double bonds have been simulated by molecular mechanics calculations (MM). In this review, the results of our MM and DSC studies carried out with various mixed‐chain phospholipids are summarized. In addition, we emphasize that the combined approach of MM and DSC yields unique uniformation that can correlate the various Tm‐profiles seen in the Tm‐diagram with the structural variation of mixed‐chain lipids as caused by the introduction of different numbers/positions of methylene‐interrupted cis‐double bonds.
Inhibitory effect of conjugated linoleic acid on linoleic acid elongation in transformed yeast with human elongase
Authors: Chuang Lu‐Te , Leonard Amanda E. , Liu Jim‐Wen , Mukerji Pradip , Bray Tammy M. , Huang Yung‐Sheng 
Published: November 2006

AbstractConjugated linoleic acid (CLA; 18∶2) refers to a group of positional and geometric isomers derived from linoleic acid (LA; Δ9, 12–18∶2). Using a growing baker's yeast (Saccharomyces cerevisiae) transformed with human elongase gene, we examined the inhibitory effect of CLA at various concentrations (10, 25, 50, and 100 μM) on elongation of LA (25 μM) to eicosadienoic acid (EDA; Δ11,14–20∶2). Among four available individual CLA isomers, only c9,t11‐ and t10,c12‐isomers inhibited elongation of LA to EDA. The extent of inhibition (ranging from 20 to 60%) was related to the concentration of CLA added to the medium. In the meantime, only these two isomers, when added at 50 μM to the media, were elongated to conjugated EDA (c11,t13‐ and t12,c14–20∶2) by the same recombinant elongase at the rate of 28 and 24%, respectively. The inhibitory effect of CLA on LA elongation is possibly due to competition between CLA isomers and LA for the recombinant elongase. Thus, results from this study and a previous study suggest that the biological effect of CLA is exerted through its inhibitory effect on Δ6‐desaturation as well as elongation of LA which results in a decrease in long‐chain n−6 fatty acids and consequently the eicosanoid synthesis.
A unique antioxidant activity of phosphatidylserine on iron‐induced lipid peroxidation of phospholipid bilayers
Authors: Dacaranhe Clemente Dique , Terao Junji 
Published: November 2006

AbstractThe relationship between the antioxidant effect of acidic phospholipids, phosphatidic acid (PA), phosphatidylglycerol (PG) and phosphatidylserine (PS), on iron‐induced lipid peroxidation of phospholipid bilayers and their abilities to bind iron ion was examined in egg yolk phosphatidylcholine large unilamellar vesicles (EYPC LUV). The effect of each acidic phospholipid added to the vesicles at 10 mol% was assessed by measuring phosphatidylcholine hydroperoxides (PC‐OOH) and thiobarbituric acid‐reactive substances. The addition of dipalmitoyl PS (DPPS) showed a significant inhibitory effect, although the other two acidic phospholipids, dipalmitoyl PA (DPPA) and dipalmitoyl PC (DPPG), did not exert the inhibition. Neither dipalmitoyl PC (DPPC) nor dipalmitoyl phophatidylethanolamine (DPPE) showed any remarkable inhibition on this system. None of the tested phospholipids affected the lipid peroxidation rate remarkably when the vesicles were exposed to a water‐soluble radical generator. The iron‐binding ability of each phospholipid was estimated on the basis of the amounts of iron recovered in the chloroform/methanol phase after separation of the vesicle solution to water/methanol and chloroform/methanol phases. EYPC LUV containing DPPS, DPPA, and DPPG had higher amounts of bound iron than those containing DPPC and DPPE, indicating that these three acidic phospholipids possess an iron‐binding ability at a similar level. Nevertheless, only DPPS suppressed iron‐dependent decomposition of PC‐OOH significantly. Therefore, it is likely that these three acidic phospholipids possess a significant iron‐binding ability, although this ability per se does not warrant them antioxidative activities. The ability to suppress the iron‐dependent decomposition of PC‐OOH may explain the unique antioxidant activity of PS.
Antioxidative activity of 3,4‐dihydroxyphenylacetic acid and caffeic acid in rat plasma
Authors: Raneva Violeta , Shimasaki Hiroyuki , Ishida Yumi , Ueta Nobuo , Niki Etsuo 
Published: November 2006

AbstractThe purpose of the present paper is to study and compare in vitro the inhibitory effect of 3,4‐dihydroxyphenylacetic acid (DOPAC) and caffeic acid (CA) on lipid peroxidation in rat plasma. Rat plasma was oxidized at 37°C by the radical initiators 2,2′‐azobis(2‐amidinopropane) dihydrochloride (AAPH) or 2,2′‐azobis(4‐methoxy‐2,4‐dimethylvaleronitrile) (MeO‐AMVN). The consumption of endogenous α‐tocopherol (α‐TOH) and the accumulation of conjugated diene hydroperoxides were measured by high‐performance liquid chromatography and by ultraviolet spectroscopy, respectively. α‐TOH was consumed at the same rate in the presence of 20 mM AAPH or 2 mM MeO‐AMVN. DOPAC and CA suppressed the α‐TOH consumption in a dose‐dependent manner. A concentration of 50 μM of both phenolic acids was sufficient to induce a lag phase and to delay the rate of α‐TOH consumption. The effect was more pronounced in rat plasma oxidation by AAPH than by MeO‐AMVN. CA spared vitamin E more effectively than DOPAC in both oxidations. DOPAC and CA suppressed the formation of conjugated diene hydroperoxides. DOPAC and CA at concentration 50 μM suppressed α‐TOH consumption during oxidation of soybean phosphatidylcholine (2.8 mM) multilamellar vesicles containing 15 μM α‐TOH, in which the lipophilic initiator 2,2′‐azobis (2,4‐dimethylvaleronitrile) (6 mM) was incorporated. In conclusion, we demonstrated that DOPAC and CA in micromolar concentrations have antioxidant activity in rat plasma, a medium very close to the conditions in vivo, suggesting that supplementation with the phenolic acids will provide significant antioxidant protection.